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ater Supplies

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The Cooperative Research Centre (CRC) for Water Quality andTreatment is Australia's national drinking water research centre.An unincorporated joint venture between 30 different organisationsfrom the Australian water industry, major universities, CSIRO, andlocal and state governments, the CRC combines expertise in waterquality and public health.

The CRC for Water Quality and Treatment is established andsupported under the Federal Government's Cooperative ResearchCentres Program.

A Guide To HazardIdentification &Risk Assessment ForDrinking WaterSupplies

A Guide To Hazard Identification &

Risk Assessment For Drinking Water Supplies

Peter Nadebaum, Michael Chapman,Robert Morden and Samantha Rizak

CRC for Water Quality and Treatment

Research Report Number 11

APRIL 2004

Cooperative Research Centre for Water Quality and Treatment Private Mail Bag 3Salisbury SA 5108AUSTRALIA

Telephone: +61 8 8259 0211Fax: +61 8 8259 0228E-mail: [email protected] site: www.waterquality.crc.org.au

2

DISCLAIMER

• The Cooperative Research Centre for Water Quality and Treatment and individual contributors are not responsible for the outcomes of any actions taken on the basis of information in this research report, nor for any errors and omissions.

• The Cooperative Research Centre for Water Quality and Treatment and individual contributors disclaim all and any liability to any person in respect of anything, and the consequences of anything, done or omitted to be done by a person in reliance upon the whole or any part of this research report.

• The research report does not purport to be a comprehensive statement and analysis of its subject matter, and if further expert advice is required, the services of a competent professional should be sought.

© CRC for Water Quality and Treatment 2004

A Guide To Hazard Identification & Risk Assessment For Drinking Water Supplies

Research Report 11ISBN 1876616121


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Foreword

A Guide to Hazard Identification & Risk Assessment for Drinking Water Supplies

Research Officers: Michael Chapman, Robert Morden

Project Leader: Dr Peter R. Nadebaum

Research Node: Egis Consulting Australia Pty Ltd

CRC for Water Quality and Treatment Project No. 1.1.6 – Drinking Water Quality Risk Guidance


4

The Cooperative Research Centre for Water Quality and Treatment, in collaboration with the National Health and Medical Research Council/Natural Resource Management Ministerial Council (NHMRC/NRMMC) and key stakeholders, has developed a Framework for Management of Drinking Water Quality (the Framework) for incorporation into the Australian Drinking Water Guidelines most recent revisions. The Framework promotes increased awareness of a comprehensive preventive strategy for drinking water quality management based on quality and risk management principles. It provides guidance on a proactive approach for minimising health risk in water supply systems and provides greater attention and better measures of control for system management, extending from the catchment to the consumer.

The Framework was developed as a quality management approach designed specifically for drinking water systems and addressed several elements considered good practice in system management of drinking water supplies. A key feature of the Framework is system analysis and system management. This involves understanding the entire water supply system, the hazards and events that can compromise drinking water quality, and the preventive measures and operational control necessary for assuring safe and reliable drinking water.

Many of the larger drinking water suppliers across Australia have already undertaken some form of drinking water quality hazard identification and risk assessment, and review of their management strategies. Many of the smaller drinking water suppliers and local councils are equally interested in the Framework but have been slower to explore its implementation due to limitations in resources and technical knowledge. Provision of technical information to adequately identify hazards and prioritise

risk (quantifying likelihood, impact and uncertainties), and to develop specific preventive measures is considered highly beneficial in achieving the goal of a safe water supply.

This document is intended to provide water authorities and other organisations with guidance which will assist in their assessment and management of risks to water quality, with particular emphasis on conducting hazard identification and risk assessment. Preventive measures and management strategies necessary for controlling hazards are also highlighted. Additional information and guidance on the Framework are provided in the current revisions to the Australian Drinking Water Guidelines.

This document includes:

• a methodology for conducting hazard identification and risk assessment;

• checklists of common sources of hazards to water quality and hazardous events;

• hazard fact sheets outlining issues associated with common sources and hazardous events, and possible preventive measures for managing the risk;

• various case studies to illustrate consequences from unforeseen and rare events;

• a summary of hazards to assist understanding of the various contaminants that may be found in drinking water.

The outcomes of this process include understanding the characteristics of the drinking water system, what hazards may arise, how these hazards create risks, the processes and practices that affect drinking water quality, and where improvements may be needed.

Executive Summary


55

Table of Contents

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

TABLE OF CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

INDEX OF HAZARD FACT SHEETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

1.1 Scope of Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

1.2 Preparation of Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

1.3 Limitations of Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

2 HAZARD IDENTIFICATION AND RISK ASSESSMENT METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . .11

2.1 Understand Your Water Supply System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

2.2 Identify Hazards, Hazardous Events and Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

2.3 Estimate Risk for Each Identified Hazard/Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

2.4 Plan Preventive Measures for Each Identified Hazard/Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

2.5 Implement and Monitor Preventive Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

2.6 Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

LIST OF TABLES

Table 1.1 Framework for Management of Drinking Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Table 1.2 Terminology – Hazard Identification and Risk Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Table 2.1 Key Characteristics of the Drinking Water Supply System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Table 2.2 Examples of Potential Sources of Hazards and Hazardous Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Table 2.3 Qualitative Measures of Likelihood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Table 2.4 Qualitative Measures of Consequence or Impact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Table 2.5 Qualitative Risk Analysis Matrix – Level of Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Table 2.6 Example Hazard Identification and Risk Assessment Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Table 2.7 Example Process Control Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

APPENDIX A: HAZARD FACT SHEETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

APPENDIX B: CASE STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71

APPENDIX C: SUMMARY OF HAZARDS (CONTAMINANTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101


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Index Of Hazard Fact SheetsCatchments and Groundwater Systems

1. Agriculture within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2. Environmental Hazards within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3. Human Access to Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4. Industrial Development within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5. Forestry within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

6. Waste Management / Wastewater Facilities within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

7. Land Use within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

8. Roads within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9. Urban Development within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Reservoirs and Basins

10. Algal Blooms within Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

11. Residence Time, Short Circuiting and Stratifi cation of Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

12. Contaminated Infl ows into Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

13. Excessive Draw or Fill of Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Water Treatment Plants (WTPs)

14. WTP Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

15. WTP Design Capability – Toxins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

16. WTP Design Capability – Alkalinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

17. WTP Design Capability – Colour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

18. WTP Design Capability - Iron & Manganese . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

19. WTP Design Capability - Industrial Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

20. WTP Design Capability – Microbiological Contamination (Pathogens) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

21. WTP Design Capability - Taste and Odour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

22. WTP Design Capability – Turbidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Disinfection Systems

23. Disinfection System Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

24. Disinfection System Design Capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Service Reservoirs and Tanks

25. Contamination of Service Reservoirs and Tanks with Floating Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

26. Contamination of Timber Service Reservoirs and Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

27. Internal Contamination of Service Reservoirs and Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

28. External Contamination of Service Reservoirs and Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Pipelines and Distribution Systems

29. Pipeline Repairs and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

30. Cleaning of Mains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

31. Pipe Materials, Private Mains and Customer Plumbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

32. High Flow in Pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

33. Backfl ow and Cross Connections in Pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

34. Reverse Flow in Pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

35. Stagnant Water in Pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

36. Aqueducts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70


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1 Introduction

The Australian Drinking Water Guidelines recognise the primary importance of a preventive, multi-barrier approach for the protection of public health in drinking water supply and has incorporated a Framework for Management of Drinking Water Quality (the Framework) in its most recent revisions. The Framework, developed by the NHMRC/NRMMC in collaboration with the CRC for Water Quality and Treatment and key stakeholders, promotes increased awareness of a comprehensive preventive strategy for drinking water quality management based on quality and risk management principles. It provides guidance on a proactive approach for minimising health risk in water supply systems and provides greater attention and better measures of control for system management, extending from the catchment to the consumer.

The Framework addresses four general areas and includes twelve elements considered good practice in system management of drinking water supplies (Table 1.1). The Framework was developed as a quality management approach designed specifically for drinking water systems. It includes principles of established systems such as ISO 9001 (Quality Management), ISO 14001 (Environmental Management), AS/NZS 4360 (Risk Management), and the Hazard Analysis and Critical Control Point (HACCP) system (as used in the food industry) but applies these in a drinking water supply context to support consistent and comprehensive implementation by drinking water suppliers.

The Framework outlines principles of management applicable for all water supply systems regardless of size or system complexity, and it is intended to allow sufficient flexibility for individual organisations to implement it in

a manner that suits their own circumstances. Current management applied by most drinking water suppliers and associated agencies will already incorporate many of the elements specified in the Framework. In many instances, all that may be needed is to review, document and formalise these practices and address any areas where improvements are required.

Furthermore, many of the larger drinking water suppliers across Australia have already undertaken some form of drinking water quality hazard identification and risk assessment, and review of their management strategies. Many of the smaller drinking water suppliers and local councils are equally interested in the Framework but have been slower to explore its implementation due to limitations in resources and technical knowledge. Provision of technical information to adequately identify hazards and prioritise risk (quantifying likelihood, impact and uncertainties), and to develop specific preventive measures is considered highly beneficial in achieving the goal of a safe water supply.

This document is intended to provide complimentary guidance on Element 2, Assessment of the Drinking Water Supply System, with particular emphasis on conducting hazard identification and risk assessment. The methodology and technical guidance in this document can assist drinking water suppliers in understanding their water supply system, the hazards and events that can compromise drinking water quality, and the preventive measures necessary for assuring safe and reliable drinking water. Additional information and guidance on the Framework are provided in the current revisions to the Australian Drinking Water Guidelines.


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Table 1.1 Framework for Management of Drinking Water Quality

COMMITMENT TO DRINKING WATER QUALITY MANAGEMENT Element 1 Commitment to Drinking Water Quality Management

Drinking Water Quality Policy Regulatory and Formal Requirements Engaging Stakeholders

SYSTEM ANALYSIS AND MANAGEMENT Element 2 Assessment of the Drinking Water Supply System

Water Supply System Analysis Assessment of Water Quality Data Hazard Identification and Risk Assessment

Element 3 Preventive Measures for Drinking Water Quality Management Preventive Measures and Multiple Barriers Critical Control Points

Element 4 Operational Procedures and Process Control Operational Procedures Operational Monitoring Corrective Action Equipment Capability and Maintenance Materials and Chemicals

Element 5 Verification of Drinking Water Quality Drinking Water Quality Monitoring Consumer Satisfaction Short-term Evaluation of Results Corrective Action

Element 6 Management of Incidents and Emergencies Communication Incident and Emergency Response Protocols

SUPPORTING REQUIREMENTS Element 7 Employee Awareness and Training

Employee Awareness and Involvement Employee Training

Element 8 Community Involvement and Awareness Community Consultation Communication

Element 9 Research and Development Investigative Studies and Research Monitoring Validation of Processes Design of Equipment

Element 10 Documentation and Reporting Management of Documentation and Records Reporting

REVIEW Element 11 Evaluation and Audit

Long-term Evaluation of Results Audit of Drinking Water Quality Management

Element 12 Review and Continual Improvement Review by Senior Executive Drinking Water Quality Management Improvement Plan


9

• “Hazards” are biological, chemical, physical or radiological agents that have the potential to cause harm and/or can give rise to water quality which is unacceptable for consumers. An example of a hazard is the protozoan parasite Cryptosporidium parvum which, if present in suffi cient numbers, can cause illness.

• “Hazardous events” and “sources of hazards” are those incidents or situations that can contribute to the presence of a hazard (what can happen and how). This may include point sources of pollution such as human and industrial waste discharge as well as diffuse sources such as those arising from agricultural and animal husbandry activities. Other examples include continuous, intermittent or seasonal pollution patterns as well as extreme and infrequent events such as droughts or fl oods. Using Cryptosporidium as an example, failure at a water treatment plant leading to C. parvum passing into the distribution system is a hazardous event.

• “Hazard identifi cation” is the systematic evaluation of a water supply system to recognise existence of hazards and defi ne their characteristics.

• “Preventive measures” are any planned actions, activities or processes used to prevent hazards from occurring or reduce them to acceptable levels. Preventive measures should be comprehensive from catchment to consumer for each identifi ed hazard.

• “Risk” is the probability or likelihood of an identifi ed hazard causing harm in exposed populations, including the magnitude of that harm, i.e. the severity of the consequences or the effect. For example, the likelihood of C. parvum being present in source waters and passing though the treatment plant in suffi cient numbers and infectivity to cause illness is the risk. Consequence may be established by considering factors such as the number of people who may get ill, degree of public outrage, size of the system contaminated, extent of boil water notices which would need to be issued, and any costs that may be incurred (e.g. fi nes, compensation, water treatment facilities upgrades, etc).

• “Risk assessment” is the systematic process of using available information to predict how often identifi ed hazards or specifi ed events may occur (likelihood) and the magnitude of their consequences. Risk should be assessed at two levels: maximum risk in the absence of preventive measures, and residual risk after consideration of existing preventive measures.

• “Risk management” refers to the overall process of evaluating the water supply system, identifying hazards, sources and hazardous events, assessing and prioritising risks, and developing and implementing effective preventive measures and strategies to manage the risks.

Table 1.2 Terminology – Hazard Identifi cation and Risk Assessment

1.1 Scope of Document

The objective of this document is to provide drinking water suppliers and other organisations with a reference document and technical guidance which will assist in their assessment and management of risks to drinking water quality, as required by the Framework for Management of Drinking Water Quality. The document includes:

1. a methodology for conducting hazard identification and risk assessment, in accordance with the Framework for Management of Drinking Water Quality which is derived from AS/NZS 4360 (Risk Management) and Hazard Analysis and Critical Control Point (HACCP) principles and the multiple barrier approach promoted within the Australian Drinking Water Guidelines.

2. checklists of key characteristics and common sources of hazards to water quality and hazardous events for the major components of water supply systems (eg catchments, source waters, storage reservoirs, major transfer pipelines/aqueducts, treatment systems, service reservoirs/tanks/basins, distribution system and consumers).

3. hazard fact sheets for each of these potential sources and hazardous events, outlining issues

associated with each source, the resultant hazards, and possible preventive measures for managing the risk. These fact sheets include information to assist organisations in understanding and evaluating situations to determine the levels of severity, impact and likelihood associated with the appearance of various water quality hazards found in drinking water in typical Australian situations. This enables an estimation of the risk for the hazard so that priorities for risk management can be established.

4. case studies detailing potential risks from unforeseen and rare events in water supply systems. And

5. summary of hazards to assist in understanding the contaminants that may be found in drinking water, their occurrence in Australia and their effects.

Terminology of drinking water quality hazard identifi cation/risk assessment can be confusing but should be clearly understood. Defi nitions of important terminology from the Framework which are used in this document are included in Table 1.2.


10

1.2 Preparation of Document

The methodology and information outlined in this document has developed from a number of sources over the period 1999 - 2002:

• The Framework for Management of Drinking Water Quality developed by the NHMRC Drinking Water Review Coordinating Group in collaboration with the CRC for Water Quality and Treatment; and

• Water quality hazard identifi cation and risk assessments of water supply systems carried out by Egis Consulting Australia for drinking water suppliers in Western Australia, South Australia, ACT, New South Wales, Queensland, Victoria and New Zealand.

The development of the approach used for assessment of the water supply system has evolved over the period 1997 - 2002. It has been found that the practical requirements of water quality hazard identifi cation and risk assessment represent a balance between:

• Suffi cient depth of analysis to understand the important issues and allow the setting of priorities for risk management for each water supply system without becoming too detailed to inhibit progress;

• Providing an understanding of the way in which hazards are reduced through a series of preventive measures or barriers, and where these measures may need improvement; and

• Time and cost and availability of staff and resources to carry out the assessment.

The preparation of this document has involved a continuing process of development, drawing on the experience and fi ndings or each new water quality hazard identifi cation and risk assessment undertaken.

1.3 Limitations of Document

This document should not be viewed as a comprehensive and complete source that outlines all relevant information and every potential risk to drinking water quality. Rather, it is intended to provide a sound starting point for a review of hazards, assessment of risks and evaluation of preventive measures for common drinking water quality hazards, and also to provide a basis for investigating other sources of hazards outside those defi ned in this document. It outlines a methodology which can provide a consistent systematic approach to risk management for Australian drinking water suppliers.

Risk assessment and risk management are not static and should be capable of accommodating change. These involve an ongoing and iterative process of improvement achieved by regularly evaluating and reviewing knowledge.


11

The methodology for assessing the water supply system and conducting hazard identifi cation/risk assessment outlined in the Framework for Management of Drinking Water Quality incorporates the multiple barrier approach and the catchment to consumer philosophy of the Australian Drinking Water Guidelines and was derived from the following risk management systems and methodologies:

• Australian/New Zealand Standard for Risk Management (AS/NZS 4360:1999); and

• Hazard Analysis and Critical Control Point (HACCP) as used in the food industry and adapted for drinking water quality management.

The resultant methodology can be described by the following schematic. It highlights steps in undertaking a hazard identifi cation/risk assessment that can be followed by drinking water suppliers to ensure all signifi cant hazards and risks to drinking water quality in their particular water supply system are identifi ed and adequately addressed.

This assessment of the drinking water supply system should be documented and recorded to provide an information base and to demonstrate how the process was carried out. Documentation also provides written evidence which justifi es the conclusions drawn and to satisfy audit and review requirements.

2 Hazard Identifi cation and Risk Assessment Methodology

Implement and monitor preventive measuresThis correlates with elements of ‘risk treatment’ and ‘monitor and review’ in AS/NZS 4360 and Principles 3-7 of HACCP

(establish critical limits and monitoring systems, corrective action and verifi cation procedures, and documentation).

Understand the water supply systemThis correlates with establishing the context in AS/NZS 4360 and preliminary steps in HACCP.

Identify hazards, hazardous events, and sourcesThis correlates with ‘risk identifi cation’ in AS/NZS 4360 and Principle 1 ‘Hazard Identifi cation’ in HACCP.

Estimate the level of risk for each identifi ed hazard/event(Consider likelihood and consequence/impact/severity)

This correlates with ‘risk analysis’ and ‘risk evaluation’ in AS/NZS 4360 and Principle 1 ‘Hazard Identifi cation’ in HACCP.

Identify and plan preventive measures for each hazard/eventThis correlates with elements of ‘risk analysis’ and ‘risk treatment’ in AS/NZS 4360 and Principle 1 ‘Hazard Identifi cation’ and

Principle 2 ‘Critical Control Points’ in HACCP.


12

2.1 Understand Your Water Supply System

To prepare for a hazard identifi cation and risk assessment, assemble a team and collect pertinent information on the water supply system from catchment to consumer.

Effective system management needs, fi rst and foremost, an understanding of the drinking water supply system. The drinking water supply system is defi ned as everything from the point of collection of water to the consumer and can include:

• catchments including groundwater systems,• source waters,• storage reservoirs and intakes,• treatment systems,• service reservoirs and distribution systems, and• consumers.

Each component of the water supply system should be characterised with respect to drinking water quality and the factors that affect it. This characterisation promotes understanding of the water supply system, and assists with identifi cation of hazards and assessment of risks to water quality.

Firstly, a team with appropriate knowledge and expertise should be assembled to carry out the assessment. The team should include management and operations staff from the drinking water supplier as well as representatives from relevant agencies (e.g. catchment and planning agencies, natural resource and environment departments). In most cases, consultation with other agencies will be required for the analysis of catchments including the potential impacts of land uses on water quality and stream and river fl ows. Health and other regulatory agencies should also be involved to increase communication and understanding of the water supply system.

A generalised fl ow diagram of the water supply system from catchment to consumer should be constructed and key characteristics documented. This diagram should:

• outline all activities, steps and processes regardless if they are not under control of the drinking water supplier,

• summarise the basic characteristics of each component,

• make explicit any characteristics that are unique to the system; and

• be verifi ed by fi eld audits and checked by those with specifi c knowledge of the system.

The purpose of this step is to develop a broad overview and basic understanding of the water supply system. It is not intended to be an extensive data collection exercise but rather the characterisation of the system at an appropriate level of detail to provide a useful information base to make effective decisions. Table 2.1 (see page12) provides examples of some key characteristics to be considered.

This characterisation should be reviewed on a periodic basis to incorporate any changes that occur (e.g. land use, treatment processes, consumer distribution).

2.2 Identify Hazards, Hazardous Events and Sources

Review potential hazardous agents in drinking water and identify the sources of hazards and hazardous events that can lead to the presence of these hazards throughout the drinking water supply system (what can happen and how).

The purpose of this step is to identify and document all potential hazards, hazardous events and sources so that associated risks can be estimated and prioritised and effective risk management strategies developed. All potential hazards, hazardous events and sources should be included in the assessment regardless of whether or not they are under the direct control of the drinking water supplier. Continuous, intermittent or seasonal pollution patterns should also be considered as well as extreme and infrequent events such as droughts, fl oods or bushfi res.

A structured approach is important to ensure that signifi cant issues are not overlooked and that areas of greatest risk are identifi ed. There is no single right way to perform these tasks, however, the process should involve a structured and comprehensive evaluation of the water supply system. A checklist of some important sources of hazards and hazardous events is provided in Table 2.2 (see page 13). This checklist should be regarded as a prompt, and may not constitute a comprehensive list. Information collected during activities associated with ‘understanding your water supply system’ should be reviewed to identify additional sources of hazards to water quality that are specifi c to the system under consideration.

Additionally, interviews of people with knowledge of the water supply system such as operational and maintenance staff (including contractors) and representatives from relevant external agencies (eg catchment management and planning authorities, neighbouring water authorities) can provide valuable information on the specifi c hazards relevant to the water supply system in question, as well as the controls that are currently in place to manage the associated risks. These interviews will involve using the information provided in this manual as a spring-board for discussion of the hazards specifi c to the system, and to ensure that key issues are not overlooked. Interviews should involve a review of any history of “near misses” and past events where specifi c hazards appeared or associated issues were witnessed or reported.

Inspections of key locations or operational activities can also provide further information on potential hazards. It is also valuable to conduct spot-checks of existing treatment or control measures to confi rm their effectiveness. Where resources are limited, review of regular site inspection reports, unplanned maintenance records and operator log books may be used to replace a detailed site inspection. Available reports and other documentation should be collected and reviewed to obtain a good understanding of the hazards.

The hazard identifi cation and risk assessment should be reviewed and updated on a periodic basis; changing conditions may introduce important new hazards or modify risks associated with identifi ed hazards.


13

Table 2.1 - Key characteristics of the drinking water supply system

Catchments

• Geology and soils• Topography and drainage patterns (hydrology)• Streams and rivers• Meteorology and weather patterns (climactic and

seasonal variations)• Riparian conditions • Vegetative cover • General catchment and river health • Wildlife (eg native and feral animals) • Historical contaminated sites • Competing water uses • Land irrigation practices

• Nature and intensity of development / land use activities:- Agricultural, dairy and animal husbandry- Land clearing - Forestry- Mining- Industrial- Rural and urban development / residential- Sewage treatment works and septic tanks- Recreational activity

• Intermittent or seasonal use practices• Future planning activities • Development and planning restrictions

Source Water

• Surface water (river, reservoir, dam)• Groundwater• Flow and reliability of source water • Seasonal and event changes (including infrequent

events such as droughts or fl oods) • Spatial variations

• General and unique constituents (physical, chemical, microbial):- Major ions and pH- Salinity, hardness- Turbidity- Bacteria, viruses and protozoa- Naturally occurring organics- Volatile and nonvolatile synthetic organics- Metals and radionuclides

Groundwater Systems

• Geology, homogeneity• Confi ned or unconfi ned aquifer• Depth to water table• Flow rate and direction

• Dilution characteristics• Recharge area• Well-head protection • Depth of casing

Storage Reservoirs and Intakes

• Detention times• Reservoir design:

- size- materials- storage capacity- depth of storage

• Seasonal variations:- stratifi cation- algal blooms

• Treatment effi ciencies (microbial removal)• Protection (e.g. covers, enclosures, access)• Recreational/human activity• Intake location and operation• Bulk transport:

- pipeline material- length- fl owrate and changes in fl owrate- cleaning systems

Treatment Systems

• Treatment processes (including optional processes)• Treatment confi guration• Equipment design:

- size- materials- peak fl ow rates- process change control - backup systems

• Monitoring equipment and automation

• Water treatment chemicals used:- coagulant- fi ltration aids- fl uoride- powdered activated carbon- disinfectant

• Treatment effi ciencies• Disinfection log removals of pathogens • Disinfection residual / contact period time

Service Reservoirs and Distribution Systems

• Reservoir design:- size- materials- storage capacity- depth of storage

• Detention times• Seasonal variations:

- stratifi cation• Protection (e.g. covers, enclosures, access)

• Distribution system design:- size- network- pipe materials- pipe age

• Hydraulic conditions (e.g. detention times, fl ows)• Backfl ow protection• Secondary disinfection practices• Disinfectant residuals • Disinfection byproducts

Consumers

• Consumer distribution (industry, bodies corporate, general community)

• Vulnerable groups (hospitals, nursing homes)

• Water demand and patterns of drinking water consumption (diurnal and seasonal variations)

• Internal plumbing


14

Table 2.2 – Examples of potential sources of hazards and hazardous events

Catchments and Groundwater Systems

1. Agriculture Within Catchments• Intensive animal/crop farming• Entry by grazing animals via breaks in fences (cattle, sheep, kangaroos)• Pesticide/herbicide spraying• Fertiliser transport and application

2. Environmental Hazards Within Catchments• Bush fi re• Storm events causing high pollutant load• Native and feral animal population (including uncollected dead animals)• Geology (slope stability/erosion, sediment, and groundwater, including groundwater contamination/salinity)

3. Human Access to Catchments• Illegal human access to water supply catchment including illegal dumping of chemical, medical, or household waste, and

terrorism.• Bushwalking, camping• Fishing, marroning• Boating• 4WDing, rally driving• Picnics• Swimming

4. Industrial Development Within Catchments• Chemical and sewage waste discharges• Chemical spills and storage• Fire• Erosion• Mining activities and waste

5. Forestry within Catchments• Timber harvesting activities• Tree establishment and maintenance (e.g. fertiliser/pesticide use)• Equipment maintenance and operation

6. Waste Management/Wastewater Facilities Within Catchments• Wastewater facilities (including treatment plants, major waste pipelines, septic tanks)• Waste management facilities (landfi lls, waste recycling centres, waste from medical facilities)

7. Land Use Within Catchments• Large range of land uses within catchment• Level of protection, current/future range of activities in catchment• Inappropriate land use protection requirements

8. Roads Within Catchments• Erosion of roadway or road shoulder• Spills of hazardous materials (chemicals, septic waste, etc.)• Runoff from road

9. Urban Development Within Catchments• Stormwater discharge (direct discharge to catchment and overfl ow into catchment)• Fire (caused by various human activities)


10. Algal Blooms within Reservoirs• Various hazards associated with algal blooms – pathogens, toxins, odour, colour, taste• Filter blocking• Odour, colour and taste from algicide dosing

11. Residence Time, Short Circuiting, and Stratifi cation of Reservoirs• Reduced residence time• Short circuiting• Stratifi cation, destratifi cation, aeration


15

12. Contaminated Infl ows into Reservoirs• Infl ow of contaminated surface water• Ingress of contaminated ground water• Maintenance/cleaning causing re-suspension of sediments

13. Excessive Draw or Fill of Reservoirs• Excessive draw down causing reduced residence time and exposing unstable surfaces for erosion, hazards to animals and

vegetation regrowth • High rates of fi ll inundating large regrowth vegetation areas too quickly• High rates of draw down causing erosion and land slips15

Water Treatment (WTP)

14. Water Treatment Plant (WTP) Reliability• Reliability of plant and equipment• Use of incorrect or contaminated chemicals• Uncontrolled changes in fl owrates of water or dosing chemicals

15. WTP Design Capability – Toxins• Toxins in raw water which exceeds the maximum design level• Toxins in raw water which exceeds the maximum design rate of change• The normal target for toxin levels in treated water is incorrectly set

16. WTP Design Capability – Alkalinity 17. WTP Design Capability – Colour 18. WTP Design Capability – Iron and Manganese 19. WTP Design Capability – Industrial Chemicals 20. WTP Design Capability – Microbiological Contamination (Pathogens) 21. WTP Design Capability – Taste and Odour 22. WTP Design Capability – Turbidity


23. Disinfection System Reliability• Reliability of disinfection plant and equipment• Use of contaminated chemicals• Uncontrolled changes in fl owrates of water or disinfectants

24. Disinfection System Design Capability• Pathogens in raw water which exceeds the maximum design limit• Pathogens in raw water which exceeds the maximum design rate of change• The normal treated water target for pathogen levels is incorrectly set


25. Contamination of Service Reservoirs and Tanks with Floating Covers• Access by animals and birds• Microbial growth under roof/cover• Ingress of contaminated water

26. Contamination of Timber Service Reservoirs and Tanks 27. Internal Contamination of Service Reservoirs and Tanks

• Sediment/biota/slimes accumulation and release• Materials of construction eg. Concrete tanks with long residence time, leaching of timber treatment chemicals from timber

roof• Residence time/short circuiting• Chemical contamination from incorrect chemical dosing eg. spot disinfectant dosing• Corrosion

28. External Contamination of Service Reservoirs and Tanks• Access by animals/birds through fences, roofs, overfl ow drains, etc.• Animal passage through inlet control valves from upstream sources• Access by humans, including sabotage• Ingress of roof drainage• Poor maintenance of fi lters on air vents


16

2.3 Estimate Risk for Each Identifi ed Hazard/Event

Estimate the level of risk for each identifi ed hazard/hazardous event by identifying the likelihood and consequences of the event; determine priorities for risk management.

The objective of the risk assessment is to distinguish between very high and low risks so that priorities for risk management can be established and documented. Once potential hazards and their sources and events have been identifi ed throughout the system, the level of risk associated with each hazard/event needs to be estimated. Not all hazards will require the same degree of attention and risk estimation assists in directing attention and resources to those hazards that are most threatening.

The level of risk for each hazard/hazardous event can be estimated by identifying the likelihood of occurrence (eg certain, possible, rare) and evaluating the severity of consequences if the hazard/event occurred (eg insignifi cant, major, catastrophic). Generally risk assessment will often include subjective judgements based on experience and will at best be qualitative or semi-quantitative. Rarely will enough knowledge be available to complete a detailed quantitative risk assessment. Although numerical rankings can be assigned, these rankings provide a relative indication of the likelihood, consequences (severity) and risk and should not be assumed in subsequent analyses to have accuracy in absolute terms. As indicated, the aim should be to distinguish between very high and low risks.

Therefore, a consistent approach should be established for both hazard identifi cation and risk assessment. This approach needs to be transparent and fully understood by involved parties. An example of an approach to estimating the level of risk is provided in Tables 2.3, 2.4 and 2.5. There is no absolute set of rules to be followed in using these tables; rather they are offered as a general guide for the development of a consistent approach that will be relevant for the water system under study.

The appendices provide information that can assist in assessing the likelihood and consequence/severity associated with each hazard source and event:

• Hazard Fact Sheets for each source of hazard listed in Table 2.2 are provided in Appendix A. The Hazard Fact Sheets provide a more comprehensive checklist of issues that require consideration when carrying out the risk identifi cation process. Both sources of hazard (e.g. erosion) and likely hazards of importance (e.g. turbidity caused by erosion) are identifi ed along with preventive measures that can be used to prevent or minimise the risk.

• Case studies providing details on some real situations where water quality was compromised and the consequences are provided in Appendix B.

Once hazards have been identifi ed throughout the system, risk should be assessed at two levels. Firstly, maximum risk in the absence of preventive measures


29. Pipeline Repairs and Maintenance• Ingress of contaminants resulting from low pressures during pipe burst / repair events• Scour caused by abnormal fl ow during pipe burst / repair• Temporary or alternative supply arrangements during pipe repair• Ingress of contaminants during mains tapping process

30. Cleaning of Mains• Use of improper equipment• Incorrect cleaning method• Lack of cleaning strategy

31. Pipe Materials, Private Mains and Customer Plumbing• Metal corrosion• Leaching of lead or plasticisers

32. High Flow in Pipelines• Unusually high velocities causing scouring and sloughing

33. Backfl ow and Cross Connections in Pipelines• Contaminated water fl owing back out of tank or consumer point into the system

34. Reverse Flow in Pipelines• Flow in opposite direction to normal fl ow causing scouring and sloughing, negative pressures

35. Stagnant Water in Pipelines• Taste and odour problems, high pH, coliform growth

36. Aqueducts• Animal or human access• Sewage, leaking stormwater pipes, or overfl owing catch drains• Tree and plant litter• Pesticide / herbicide drift• Roads, bridges, and spills over or near the aqueduct


17

should be determined to identify the highest priority risks and provide an indication of worst case scenarios in the event of failures. Secondly, residual risk, determined in conjunction with evaluation of existing preventive measures (see Section 2.4), should also be assessed to provide information on the effectiveness of existing strategies and the need for improvements.

Based on the relative ranking of risks (both before and after considering effectiveness of existing preventive measures), signifi cant hazards can be determined and priorities for risk management documented. A likely outcome of the hazard identifi cation and risk assessment process will be the identifi cation of specifi c areas where further information and research are required. Evaluating the major sources and types of uncertainty associated with the hazards can assist in understanding the limitations of the hazard identifi cation and risk assessment as well as how these limitations can be reduced.

An example of an approach to estimating the level of risk is provided in Tables 2.3, 2.4 and 2.5. These tables have been adapted from AS/NZS 4360:1999 Risk Management

and can be modifi ed to meet the needs of an organisation. Details of each hazard source and ranking of its likelihood and signifi cance should be documented (see Section 2.6 Documentation). An example of a hazard identifi cation and risk assessment table is provided in Table 2.6. The specifi c locations of the sources of hazard and the means by which important hazards can enter the water supply should be recorded where possible, as this will assist with the development of appropriate preventive measures and effective monitoring programs.

Continual improvement is an essential feature of the Framework for Management of Drinking Water Quality and it is important that this exercise be reviewed and updated on a periodic basis as changing conditions may introduce important new hazards or modify risks associated with identifi ed hazards.

Table 2.3 Qualitative Measures of Likelihood

Level Descriptor Example Description

A Almost certain Is expected to occur in most circumstances

B Likely Will probably occur in most circumstances

C Possible Might occur at some time/the event should occur at some time

D Unlikely Could occur at some time

E Rare May occur only in exceptional circumstances

Table 2.4 Qualitative Measures of Consequence or Impact

Level Descriptor Example Description

1 Insignifi cant insignifi cant impact, little disruption to normal operation, low increase in normal operating costs

2 Minor minor impact for small population, some manageable operation disruption, some increase in operating costs

3 Moderate minor impact for large population, signifi cant modifi cation to normal operation but manageable, operating costs increased, increased monitoring

4 Major major impact for small population, systems signifi cantly compromised and abnormal operation if at all, high level of monitoring required

5 Catastrophic major impact for large population, complete failure of systems

Table 2.5 Qualitative Risk Analysis Matrix – Level of Risk

Likelihood

Consequences

1Insignifi cant

2Minor

3Moderate

4Major

5Catastrophic

A (almost certain) moderate high very high very high very high

B (likely) moderate high high very high very high

C (moderate) low moderate high very high very high

D (unlikely) low low moderate high very high

E (rare) low low moderate high high


18

2.4 Plan Preventive Measures for Each Identifi ed Hazard/Event

For each signifi cant hazard (source)/hazardous event, identify existing preventive measures from catchment to consumer, assess their overall effectiveness in preventing or reducing risk (i.e. estimate residual risk), and plan improvements where required.

Preventive measures are those actions, activities and processes used to prevent hazards from occurring or reduce them to acceptable levels. In drinking water supply systems, the control of water quality is often achieved though a number of preventive measures each of varying effectiveness in preventing/reducing the likelihood and/or severity of a hazard before it reaches consumers. Many preventive measures cover a broad spectrum and may control more than one hazard. The level of protection planned to control a hazard should be proportional to the associated risk.

For each signifi cant hazard (source)/hazardous event determined (based on the assessment of risk), identify existing preventive measures from catchment to consumer and estimate residual risk, ie evaluate whether the set of preventive measures, when considered together, are effective at reducing the risk to an acceptable level. Existing preventive measures should consider both measures applied at the source point to prevent hazards from occurring (e.g. fencing of the reservoir to prevent animal access) and downstream measures to minimise the likelihood of hazards passing through the system and being present in suffi cient numbers to cause harm to consumers (e.g. chlorination to disinfect water taken from reservoir).

If the preventive measures are not fully effective at reducing risk to acceptable levels then improvement is required. Alternate and additional preventive measures that could be applied should be identifi ed and evaluated. Wherever possible, the multiple barrier approach should be employed and preventive measures should be comprehensive from catchment to consumer. Preventive measures, by their nature, should focus on prevention in catchments rather than relying solely on downstream control where possible.

Typical preventive measures and suggestions for consideration are provided in the Hazard Fact Sheets in Appendix A.

2.5 Implement and Monitor Preventive Measures

Develop operational procedures and process control plans for the implementation and monitoring of preventive measures to ensure that processes and activities are continually carried out effectively and effi ciently.

Preventive measures should be carefully managed to ensure that appropriate practices are employed and

performance monitored to demonstrate that the hazard(s) is under control. Operational procedures and process control plans support preventive measures by detailing the specifi c operational factors to provide effective control over the process or activity.

These plans require a description of preventive measures and their functions, together with:

ß Operational procedures (both ongoing and periodic) including identifi cation of responsibilities and authorities.

ß Operational monitoring plans including the identifi cation of appropriate operational parameters that can be measured and for which target criteria and critical operating limits can be set to measure operational effectiveness and provide an indication when the process or activity is out of control and an unacceptable health risk results. For preventive measures which can signifi cantly prevent or reduce hazards, online and continuous monitoring should be used.

ß Planned corrective action procedures that can be implemented in response to deviation from target criteria and critical operating limits.

ß Appropriate documentation and record-keeping to demonstrate performance and provide an accountability mechanism.

ß Verifi cation methods including additional monitoring, inspection and auditing to assess the performance of the system and assure that preventive measures are effective and implemented appropriately.

Process control plans should be documented for appropriate preventive measures (see Section 2.6 Documentation). Table 2.7 provides an example of a process control plan for fl ushing after repairs of pipe bursts.

2.6 Documentation

Develop and document a risk management plan to address the issues identifi ed in the risk assessment.

Appropriate documentation is an important aspect of system analysis and management. This requires documenting a plan which includes the hazard identifi cation and risk assessment process and outcomes, priorities for risk management, and a description of preventive measures and their functions, together with the operational procedures and process control plans, with assigned responsibilities and timeframes, to ensure their effective implementation.

Table 2.6 provides example documentation of a hazard identifi cation and risk assessment process. An example of documentation of a process control plan is given in Table 2.7.


19

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20

Activity/Step Flushing (Cleaning) After Pipe Burst Repair

Hazards Microorganisms, chemical contaminants

Preventive measure(s) Documented operational procedure including aspects e.g. - disinfection/disnfection residual - fl ushing - crew control

Process controls Minimum time for fl ushing of mainUnidirectional fl ushing where possible Flushing at > 1.5 m/s to achieve scourDisinfectant dose

Operational monitoring What How When Where Who

Air out/clean water Visual inspectionStart of recharging of mainAt fi nal hydrantService Group

Disinfectant residualResidual analyserStart of recharging of mainUpstream/downstream of burst locationService Group

Target criteria and critical operating limits Set time until air out and clean Set appropriate disinfectant residual

Corrective action What Who

Repeat fl ushing procedureService Group

Documentation What Where Who When

Jobsheets – record of fl ushing/ cleaning activities, operational monitoring resultsWater supply owner’s offi ceAsset management groupAfter burst repair and cleaning

Verifi cation What How When/Where Who

Periodic audit of fl ushing proceduresVisual inspection; review documentation, lab resultsOnce every four-six monthsWater quality manager

Microbiological quality (faecal and total coliforms)Sampling and laboratory analysis After burst repair and cleaningService Group

Table 2.7 Example Process Control Plan


21

Appendix AHazard Fact Sheets


22

Index Of Hazard Fact SheetsCatchments and Groundwater Systems

1. Agriculture within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2. Environmental Hazards within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3. Human Access to Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4. Industrial Development within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5. Forestry within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

6. Waste Management / Wastewater Facilities within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

7. Land Use within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

8. Roads within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9. Urban Development within Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37


10. Algal Blooms within Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

11. Residence Time, Short Circuiting and Stratifi cation of Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

12. Contaminated Infl ows into Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

13. Excessive Draw or Fill of Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Water Treatment Plants (WTPs)

14. WTP Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

15. WTP Design Capability – Toxins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

16. WTP Design Capability – Alkalinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

17. WTP Design Capability – Colour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

18. WTP Design Capability - Iron & Manganese . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

19. WTP Design Capability - Industrial Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

20. WTP Design Capability – Microbiological Contamination (Pathogens) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

21. WTP Design Capability - Taste and Odour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

22. WTP Design Capability – Turbidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52


23. Disinfection System Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

24. Disinfection System Design Capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54


25. Contamination of Service Reservoirs and Tanks with Floating Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

26. Contamination of Timber Service Reservoirs and Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

27. Internal Contamination of Service Reservoirs and Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

28. External Contamination of Service Reservoirs and Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59


29. Pipeline Repairs and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

30. Cleaning of Mains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

31. Pipe Materials, Private Mains and Customer Plumbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

32. High Flow in Pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

33. Backfl ow and Cross Connections in Pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

34. Reverse Flow in Pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

35. Stagnant Water in Pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

36. Aqueducts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70


23

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in

asse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Inte

nsiv

e fa

rmin

g –

redu

ced

vege

tatio

n af

ter

plou

ghin

g an

d ov

ergr

azin

g

• M

icro

biol

ogic

al c

onta

min

atio

n• T

urbi

dity

- f

rom

ero

sion

• S

ee h

azar

ds a

ssoc

iate

d w

ith

‘Pes

ticid

e/ h

erbi

cide

spr

ayin

g’

belo

w• S

ee h

azar

ds a

ssoc

iate

d w

ith

‘App

licat

ion

of F

ertil

iser

s’ b

elow

• Are

a of

farm

ing

land

with

in t

he

catc

hmen

t• W

aste

pro

duct

s an

d m

etho

d of

di

spos

al• F

arm

ing

oper

atio

ns a

nd

man

agem

ent

prac

tices

• Mon

itori

ng o

f far

min

g pr

actic

es• B

uffe

r zo

nes

arou

nd fa

rmin

g ar

eas

• Sep

arat

e di

spos

al s

yste

m fo

r hi

gh-n

utri

ent

was

te fr

om

pigg

erie

s an

d ch

icke

n fa

rms

• Rev

iew

farm

ing

prac

tices

and

app

licat

ion

of p

reve

ntiv

e m

easu

res,

and

iden

tify

pote

ntia

l for

was

te r

un o

ff in

to w

ater

sup

ply

afte

r ra

in

Pest

icid

e/

herb

icid

e sp

rayi

ng

-in

clud

es b

aitin

g

• Che

mic

al c

onta

min

atio

n in

run

off

• Tas

te a

nd o

dour

com

poun

ds -

fr

om c

onta

min

ated

run

off

• Tur

bidi

ty -

fro

m e

rosi

on

• Lev

els

of u

sage

• Typ

es o

f che

mic

als

invo

lved

in e

ach

appl

icat

ion

• Mod

e of

ope

ratio

n of

eac

h ty

pe o

f he

rbic

ide

/ pes

ticid

e• S

easo

nalit

y of

app

licat

ions

• Typ

e of

run

off r

e-us

e sy

stem

s • N

umbe

r of

pro

pert

ies

usin

g he

rbic

ides

/ pe

stic

ides

and

the

ir

prox

imity

to

rese

rvoi

rs a

nd

offt

akes

• App

ropr

iate

her

bici

de /

pest

icid

e us

age

incl

udin

g le

vels

and

tim

ing

of

appl

icat

ions

• Use

of a

ppro

pria

te t

ypes

of

herb

icid

e / p

estic

ide

• Buf

fer

zone

s ar

ound

affe

cted

ar

eas

• Rev

iew

pes

ticid

e us

e in

cat

chm

ents

and

confi r

m t

hat

mon

itori

ng

incl

udes

ana

lysi

s fo

r al

l pes

ticid

es in

pas

t an

d pr

esen

t us

e• D

isco

urag

e ex

cess

ive

use

of p

estic

ides

and

her

bici

des

• Ens

ure

buffe

r zo

nes

exis

t ar

ound

res

ervo

irs

and

wat

erw

ays

to h

elp

redu

ce c

once

ntra

tions

of c

onta

min

atio

n an

d tu

rbid

ity• C

reat

e an

ext

ra b

uffe

r zo

ne (

say

20 m

at

the

bott

om e

nd o

f a fi

eld)

ar

ound

the

affe

cted

are

a• D

elay

irri

gatio

n fo

r at

leas

t 3

days

aft

er a

pplic

atio

n to

red

uce

the

leve

ls

of c

onta

min

ant

in s

urfa

ce r

unof

f• E

nsur

e th

e fi r

st t

wo

irri

gatio

ns a

fter

app

licat

ion

do n

ot p

rodu

ce a

ny

surf

ace

runo

ff• R

e-us

e ru

noff

to p

reve

nt c

onta

min

ated

wat

er r

each

ing

wat

erw

ays

Thi

s al

so r

educ

es t

he le

vels

of h

erbi

cide

/ pe

stic

ide

requ

ired

• Enc

oura

ge u

se o

f her

bici

des

whi

ch k

ill v

eget

atio

n w

hils

t le

avin

g pl

ant

resi

due

and

root

sto

cks

inta

ct t

o ho

ld s

oil i

n pl

ace

and

redu

ce e

rosi

on

and

turb

idity

• Ens

ure

that

any

dis

cree

t fo

rms

of p

estic

ide

(eg

pois

oned

bai

t) a

re

adeq

uate

ly c

lear

ed fr

om t

he s

ite a

fter

app

licat

ion

App

licat

ion

of

fert

ilise

rs• C

hem

ical

con

tam

inat

ion

of r

unof

f (in

clud

ing

nutr

ient

s)• T

aste

and

odo

ur c

ompo

unds

-

from

con

tam

inat

ed r

unof

f• C

yano

bact

eria

tox

ins

• Tas

te a

nd o

dour

com

poun

ds -

fr

om a

lgae

• Lev

els

of u

sage

• Typ

es o

f che

mic

als

invo

lved

in e

ach

appl

icat

ion

• Sea

sona

lity

of a

pplic

atio

ns• T

ype

of r

unof

f re-

use

syst

ems

in

plac

e• N

umbe

r of

pro

pert

ies

usin

g fe

rtili

sers

and

the

ir p

roxi

mity

to

rese

rvoi

rs a

nd o

fftak

es• P

oten

tial f

or s

pill

into

res

ervo

irs

• Pre

senc

e of

sea

sona

l sto

rage

s pr

ior

to w

ater

sup

ply

offt

ake

(alg

ae

grow

th)

• App

ropr

iate

fert

ilise

r us

age

prev

entiv

e m

easu

res

incl

udin

g le

vels

and

tim

ing

of

appl

icat

ions

• Use

of a

ppro

pria

te t

ypes

of

fert

ilise

r• B

uffe

r zo

nes

arou

nd a

ffect

ed

area

s• R

estr

ictio

ns o

n bu

lk s

tora

ge

of fe

rtili

ser

in t

he c

atch

men

t

• Rev

iew

use

of f

ertil

iser

s an

d de

term

ine

thei

r co

mpo

sitio

n• D

isco

urag

e ex

cess

ive

use

of fe

rtili

ser

• Ens

ure

buffe

r zo

nes

exis

t ar

ound

res

ervo

irs

and

wat

erw

ays

to h

elp

redu

ce t

he c

once

ntra

tion

of c

onta

min

atio

n an

d tu

rbid

ity• C

reat

e an

ext

ra b

uffe

r zo

ne (

say

20 m

at

the

bott

om e

nd o

f a fi

eld)

ar

ound

the

affe

cted

are

a. M

ore

cons

erva

tive

dist

ance

s m

ay b

e re

quir

ed

near

spr

ings

, wel

ls o

r bo

reho

les

(say

50

m)

• Del

ay ir

riga

tion

for

at le

ast

3 da

ys a

fter

app

licat

ion

to r

educ

e th

e le

vels

of

con

tam

inan

t in

sur

face

run

off

• Ens

ure

the fi r

st t

wo

irri

gatio

ns a

fter

app

licat

ion

do n

ot p

rodu

ce

surf

ace

runo

ff.• R

e-us

e ru

noff

to p

reve

nt c

onta

min

ated

wat

er r

each

ing

wat

erw

ays

Thi

s al

so r

educ

es t

he le

vels

of f

ertil

iser

req

uire

d

1. A

gri

cult

ure

wit

hin

Cat

chm

en

ts


24

Oth

er

rela

ted

Fac

t S

he

ets

: •

2. E

nvir

onm

enta

l Haz

ards

with

in C

atch

men

ts•

3. H

uman

Acc

ess

to C

atch

men

ts

• 4.

Indu

stri

al D

evel

opm

ent

with

in C

atch

men

ts•

10. A

lgal

Blo

oms

with

in R

eser

voir

s

Use

ful

Lit

era

ture

: •

Ref

er A

ppen

dice

s B,

C•

J Bad

enoc

h (C

hair

man

), C

rypt

ospo

ridi

um in

Wat

er S

uppl

ies:

Sec

ond

Rep

ort

of t

he G

roup

of E

xper

ts, H

MSO

, Lon

don,

Oct

ober

199

5.•

BJ B

ush,

KJ N

exhi

p, N

R A

ustin

, Fer

tilis

er B

est

Man

agem

ent

Prac

tices

For

Irri

gate

d Pa

stur

es, X

th W

orld

Wat

er C

ongr

ess,

Mel

bour

ne, M

arch

200

0.•

JL M

icha

el, H

L G

ibbs

, JB

Fisc

her,

EC W

ebbe

r, Pr

otec

ting

Surf

ace

Wat

er S

yste

ms

on F

ores

t Si

tes T

hrou

gh H

erbi

cide

Use

, Xth

Wor

ld W

ater

Con

gres

s, M

elbo

urne

, Mar

ch 2

000.

• G

reen

op, B

., Lo

vatt

, K. a

nd R

obb,

M., T

he u

se if

art

ifi ci

al o

xyge

natio

n to

red

uce

nutr

ient

ava

ilabi

lity

in t

he C

anni

ng R

iver

, Wes

tern

Aus

tral

ia, W

ater

Sci

ence

and

Tec

hnol

ogy,

133-

144,

200

1.

• Ph

illip

s, N

., Be

nnet

t, J.

and

Mou

lton,

D.,

Prin

cipl

es a

nd T

ools

for

Prot

ectin

g A

ustr

alia

n R

iver

s, Q

ueen

slan

d En

viro

nmen

tal P

rote

ctio

n A

genc

y, La

nd &

Wat

er A

ustr

alia

, 200

1.


25

2. E

nvi

ron

me

nta

l H

azar

ds

wit

hin

Cat

chm

en

tsS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Bushfi r

es•

Turb

idity

- f

rom

par

ticul

ate

fallo

ut•

Turb

idity

-

from

ero

sion

• M

icro

biol

ogic

al c

onta

min

atio

n -

fr

om d

ead

anim

als

• C

hem

ical

con

tam

inat

ion

- f

rom

fi r

e re

tard

ants

• H

uman

act

iviti

es w

ithin

the

cat

chm

ent

and

surr

ound

ing

area

s w

hich

cou

ld c

ause

fi re

s (e

g. ro

ads,

cam

ping

, ind

ustr

ial o

r ur

ban

deve

lopm

ent)

• D

istr

ibut

ion

of fi

re p

rone

are

as w

ithin

the

ca

tchm

ent

and

thei

r pr

oxim

ity t

o re

serv

oirs

and

w

ater

way

s•

Fire

fuel

leve

ls w

ithin

the

cat

chm

ent

• Pr

esen

ce o

f fi r

e br

eaks

• C

atch

men

t pa

rtic

ular

ly p

rone

to fi r

e

• Fi

re b

reak

s•

Coo

rdin

ated

fi re

man

agem

ent

plan

• R

estr

icte

d us

e of

fi re

ret

arda

nt

chem

ical

s

• R

evie

w o

ccur

renc

e an

d ex

tent

of

bushfi r

es•

Rev

iew

pre

vent

ive

mea

sure

s an

d ef

fect

iven

ess

• R

evie

w t

he im

pact

of l

ong-

term

fi re

-re

tard

ant

mea

sure

s

Stor

ms

• Tu

rbid

ity

-

from

ero

sion

• M

icro

biol

ogic

al c

onta

min

atio

n •

See

Fact

She

et o

n ‘R

esid

ence

T

ime,

Sho

rt C

ircu

iting

and

St

ratifi

cat

ion

of R

eser

voir

s’ (

No

11)

• St

orm

eve

nt p

roba

bilit

y•

Flow

res

ultin

g fr

om m

ajor

sto

rm c

ompa

red

with

th

e re

serv

oir

leve

l•

Flow

res

pons

e ch

arac

teri

stic

s of

cat

chm

ent

• Pr

esen

ce o

f sed

imen

t tr

aps

(nat

ural

or

artifi

cia

l)•

Cap

acity

of b

uffe

r zo

nes

in r

educ

ing

sedi

men

t an

d nu

trie

nt lo

ads

in m

ajor

sto

rms

• Ty

pes

of v

eget

atio

n an

d gr

ound

cov

er w

ithin

ca

tchm

ent

• Se

dim

ent

trap

s•

Buffe

r zo

nes

arou

nd r

eser

voir

s an

d w

ater

way

s•

Floo

d m

itiga

tion/

reta

rdat

ion

basi

ns•

Extr

actio

n m

anag

emen

t•

Alte

rnat

e w

ater

sou

rce/

use

of

wat

er s

tora

ge

• D

eter

min

e qu

ality

of s

torm

wat

er d

urin

g st

orm

eve

nts

and

asse

ss s

ignifi c

ance

w

ith r

espe

ct t

o re

ceiv

ing

wat

er•

Rev

iew

effe

ctiv

enes

s of

pre

vent

ive

mea

sure

s

Wild

life

- in

clud

es

fera

l, na

tive,

str

ay a

nd

unfe

nced

farm

ani

mal

s

• M

icro

biol

ogic

al c

onta

min

atio

n -

fr

om w

aste

and

dea

d an

imal

s•

Turb

idity

-

fr

om e

rosi

on d

ue

to o

verg

razi

ng a

nd a

nim

al t

rack

s•

Cya

noba

cter

ia t

oxin

s•

Tast

e an

d od

our

com

poun

ds -

fr

om a

lgae

•

See

‘Pes

ticid

e/ h

erbi

cide

spr

ayin

g’

re b

aitin

g (F

act

Shee

t 1)

• Fr

eque

ncy

of d

etec

tion

of h

igh

risk

fera

l ani

mal

s (e

g. pi

gs, c

attle

, sea

gulls

, dee

r)•

Num

bers

of d

ead

anim

als

foun

d in

aqu

educ

ts,

wat

erco

urse

s an

d re

serv

oirs

• N

umbe

rs o

f wat

er b

irds

roo

stin

g, es

peci

ally

nea

r di

vers

ion

poin

ts•

Shor

elin

e ve

geta

tion

dist

urba

nce

and

anim

al d

ung

dens

ity

• Pa

trol

s to

rem

ove

dead

ani

mal

s•

Fera

l / n

ativ

e an

imal

cul

ls•

Baiti

ng•

Fenc

ing

of c

atch

men

t ar

eas

• Sc

reen

s at

wat

er s

uppl

y in

let

poin

ts•

Aqu

educ

ts w

hich

ani

mal

s ca

n ea

sily

get

out

of

• Pe

riod

ic w

ildlif

e su

rvey

s•

Rev

iew

effe

ctiv

enes

s of

fera

l ani

mal

pr

even

tion

prog

ram

s•

Rev

iew

str

uctu

res

(eg.

aque

duct

s) t

o en

sure

ani

mal

s ca

n ge

t ou

t if

they

fall

in

Geo

logy

- in

rel

atio

n to

gr

ound

wat

er•

Turb

idity

- fr

om d

isso

lved

m

iner

als

(e.

g. ir

on)

• C

hem

ical

con

tam

inat

ion

-

fro

m a

rsen

ic le

achi

ng a

nd

man

gane

se (

caus

ing

stai

ning

) ,

min

eral

s

• Lo

catio

n, a

lignm

ent

and

char

acte

rist

ics

of a

quife

rs

with

in t

he c

atch

men

t•

Pres

ence

of p

oten

tially

haz

ardo

us m

iner

als

with

in

the

catc

hmen

t•

Qua

lity

of g

roun

dwat

er•

Rel

ativ

e fl o

w o

f gro

undw

ater

• Va

riab

ility

of g

roun

dwat

er q

ualit

y an

d fl o

w

• D

epth

to

wat

er t

able

• W

ater

che

mis

try

mon

itori

ng•

Hyd

rolo

gy m

onito

ring

• A

void

ance

of h

igh

arse

nic

or

man

gaan

ese

cont

ent

geol

ogy

• A

erat

ion

for

stri

ppin

g su

lphi

des

• R

emov

al o

f iro

n, m

anga

nese

or

arse

nic

cont

amin

atio

ns

• R

evie

w g

eolo

gy a

nd q

ualit

y of

gr

ound

wat

er a

nd s

urfa

ce w

ater

(eg

m

etal

s, su

lphi

des)

with

res

pect

to

impa

ct o

n w

ater

qua

lity


26

Oth

er

rela

ted

Fac

t S

he

ets

: •

4. In

dust

rial

Dev

elop

men

t w

ithin

Cat

chm

ents

• 9.

Urb

an D

evel

opm

ent

with

in C

atch

men

ts•

10. A

lgal

Blo

oms

with

in R

eser

voir

s•

11. R

esid

ence

Tim

e, S

hort

Cir

cuiti

ng a

nd S

trat

ifi ca

tion

of R

eser

voir

s

Use

ful

Lit

era

ture

: •

Ref

er A

ppen

dice

s B,

C•

Wel

sh, D

.R. a

nd S

tew

art,

D.B

. (19

89):

App

licat

ions

of i

nter

vent

ion

anal

ysis

to

mod

el t

he im

pact

of d

roug

ht a

nd b

ushfi

res

on

wat

er q

ualit

y. Au

stra

lian

Jour

nal o

f Mar

ine

and

Fres

hwat

er R

esea

rch

40: 2

41–

257.

• A

nony

mou

s, A

sses

smen

t of

the

effe

ctiv

enes

s an

d en

viro

nmen

tal r

isk

of t

he u

se o

f ret

arda

nts

to a

ssis

t in

wildfi r

e co

ntro

l in

Vic

tori

a. R

esea

rch

Rep

ort

No.

50, P

repa

red

by C

SIRO

For

estr

y an

d Fo

rest

Pr

oduc

ts fo

r th

e D

epar

tmen

t of

Nat

ural

Res

ourc

es a

nd E

nvir

onm

ent

(Vic

).•

Cra

bb, P

. Im

pact

s of

ant

hrop

ogen

ic a

ctiv

ities

, wat

er u

se a

nd c

onsu

mpt

ion

on w

ater

res

ourc

es a

nd fl

oodi

ng, A

ustr

alia

: Sta

te o

f the

Env

iron

men

t Tec

hnic

al P

aper

Ser

ies

(Inla

nd W

ater

s), D

epar

tmen

t of

th

e En

viro

nmen

t, C

anbe

rra,

1997

.•

Bren

, L.,

et a

l. C

ontr

ollin

g se

dim

ent

and

nutr

ient

mov

emen

t w

ithin

cat

chm

ents

, Coo

pera

tive

Res

earc

h C

entr

e fo

r C

atch

men

t H

ydro

logy

, 199

7.


27

3. H

um

an A

cce

ss t

o C

atch

me

nts

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Illeg

al

acce

ss t

o ca

tchm

ent/

ill

egal

du

mpi

ng o

f w

aste

• Che

mic

al c

onta

min

atio

n

- fr

om d

umpi

ng o

f ch

emic

al a

nd m

edic

al

was

te• M

icro

biol

ogic

al

cont

amin

atio

n -

from

du

mpi

ng o

f hou

seho

ld

was

te a

nd h

uman

was

te• T

urbi

dity

-

due

to

eros

ion

from

4W

D• S

ee b

ushfi

re

haza

rds

in F

act

Shee

t 2.

‘E

nvir

onm

enta

l Haz

ards

w

ithin

Cat

chm

ents

’

• Fre

quen

cy o

f acc

ess,

docu

men

ted

case

s• A

ctiv

ity d

urin

g ac

cess

(eg

fi sh

ing,

shoo

ting,

dum

plin

g of

was

te, 4

WD

)• L

ocat

ion

of a

cces

s re

lativ

e to

res

ervo

ir,

stre

ams

and

offt

ake

• Pot

entia

l for

ero

sion

• P

oten

tial f

or fi

re

• Pot

entia

l for

con

tam

inat

ion

ente

ring

re

serv

oir

and

stre

ams

• Sec

urity

fenc

ing

• Reg

ular

and

ran

dom

pat

rols

• S

igna

ge• P

ublic

edu

catio

n• B

ylaw

s• W

ater

Aut

hori

ty o

wne

rshi

p of

land

• Rev

iew

info

rmat

ion

on il

lega

l acc

ess.

Con

side

r us

e of

ele

ctro

nic

data

col

lect

ion

of r

epor

t by

ran

gers

.• C

onsi

der

effe

ctiv

enes

s of

pre

vent

ive

mea

sure

s• E

xten

d or

impr

ove

fenc

ing,

espe

cial

ly in

hig

hly

illeg

al a

cces

s ar

eas

• Lan

d bu

y ba

ck p

rogr

am• B

ylaw

s an

d pr

osec

utio

n pr

oces

s• M

emor

andu

m o

f Und

erst

andi

ng w

ith o

ther

age

ncie

s• M

inim

ise

exte

nt a

nd u

sage

of r

oadw

ays

in c

atch

men

t• E

ncou

rage

loca

l com

mun

ity p

artic

ipat

ion

in r

epor

ting

of il

lega

l ac

cess

• E

mer

genc

y re

spon

se p

lann

ing

Bush

wal

king

an

d ca

mpi

ng•

Mic

robi

olog

ical

co

ntam

inat

ion

-

from

lit

ter

and

hum

an w

aste

• See

bus

hfi r

e ha

zard

s in

Fac

t Sh

eet

2.

‘Env

iron

men

tal H

azar

ds

with

in C

atch

men

ts’

• Tur

bidi

ty

- f

rom

er

osio

n o

f wal

king

tra

ils,

road

s

• Num

bers

of c

ampe

rs• L

ocat

ion

of c

ampi

ng a

reas

rel

ativ

e to

w

ater

cour

ses,

aque

duct

s, re

serv

oirs

and

of

ftak

es• P

rovi

sion

of f

acili

ties

and

man

agem

ent

of

cam

pers

• Pot

entia

l for

fi re

• Pro

visi

on o

f fi r

e pr

even

tive

mea

sure

s• P

oten

tial f

or e

rosi

on, s

oil t

ype,

use

of

trai

ls

• Inc

iden

ce r

ate

of w

aste

dum

ping

, ille

gal

swim

min

g, an

d di

stur

banc

e of

veg

etat

ion

• Des

igna

ted

cam

ping

are

as lo

cate

d do

wns

trea

m o

f wat

er s

uppl

y di

vers

ion

poin

t an

d aw

ay fr

om w

ater

cour

ses

• Des

igna

ted

trac

ks, c

onst

ruct

ed w

alki

ng

trac

ks

• Pro

visi

on o

f pit

toile

ts

• Toi

lets

loca

ted

dow

nstr

eam

or

far

away

fr

om r

eser

voir

offt

akes

or

wat

erco

urse

s• P

reve

ntiv

e m

easu

res

over

was

te (

carr

y ou

t/bi

ns p

rovi

ded)

• Pro

hibi

tion

of w

ood fi r

es• I

ssui

ng o

f per

mits

• Rev

iew

info

rmat

ion

on b

ushw

alki

ng a

nd c

ampi

ng a

ctiv

ities

in

catc

hmen

t• K

eep

trai

ls a

nd c

amps

ites

at le

ast

300

m a

way

from

str

eam

s an

d re

serv

oirs

• Mem

oran

dum

of U

nder

stan

ding

with

bus

hwal

king

clu

bs• C

amps

ites

dow

nstr

eam

of w

ater

sup

ply

dive

rsio

n po

int

• Tra

ils s

houl

d cr

oss

stre

ams

only

at

brid

ges

or c

ulve

rts

• Im

prov

e si

gnag

e an

d ed

ucat

ion

of p

ublic

, inc

ludi

ng p

ublic

br

iefi n

gs a

nd p

amph

lets

for

wal

kers

• Day

wal

ks o

nly

polic

y• I

mpl

emen

t pe

rmit

syst

em fo

r ca

mpe

rs• N

o fi r

es a

llow

ed in

cat

chm

ent

• Byl

aws

to a

void

per

man

ent

righ

t of

way

s

Fish

ing,

mar

roni

ng• M

icro

biol

ogic

al

cont

amin

atio

n -

fro

m

hum

an a

nd fi

shin

g w

aste

• Tur

bidi

ty

- fr

om

shor

elin

e di

stur

banc

e • S

ee h

azar

ds a

ssoc

iate

d w

ith ‘B

ushw

alki

ng a

nd

cam

ping

’, ‘Bo

atin

g, ‘S

wim

min

g’

• Num

bers

of p

eopl

e in

volv

ed• F

ishi

ng fr

om b

ank

or b

oat

• Inc

iden

ce o

f ill

egal

sw

imm

ing

• Occ

urre

nce

of w

adin

g al

ong

shor

elin

e

• Pro

visi

on o

f pit

toile

ts a

nd fi

sh c

lean

ing

area

s• R

ange

r pa

trol

s• I

ssui

ng o

f per

mits

• See

Typ

ical

Pre

vent

ive

Mea

sure

s fo

r ‘B

ushw

alki

ng a

nd c

ampi

ng’, ‘

Boat

ing’

, ‘S

wim

min

g’

• Rev

iew

info

rmat

ion

on fi

shin

g an

d re

late

d ac

tiviti

es• P

rohi

bit fi s

hing

in s

ome

or a

ll ar

eas

of t

he c

atch

men

t or

re

serv

oir

• Im

plem

ent

a pe

rmit

syst

em fo

r fi s

hing

in t

he c

atch

men

t or

re

serv

oir

• Im

prov

e an

d en

cour

age

alte

rnat

ive fi s

hing

are

as o

utsi

de t

he

catc

hmen

t or

res

ervo

ir• F

ine

scre

ens

on w

ater

sup

ply

dive

rsio

n st

ruct

ures


28

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Boat

ing

• Mic

robi

olog

ical

co

ntam

inat

ion

-

from

lit

ter

and

hum

an w

aste

• Che

mic

al c

onta

min

atio

n

- f

rom

fuel

pet

role

um

hydr

ocar

bons

• T

urbi

dity

-

from

tr

ack

eros

ion

due

to

wal

king

and

dri

ving

, and

di

stur

banc

e of

sho

relin

e

• Num

ber

of b

oats

invo

lved

• Typ

es o

f boa

ts (

win

dsur

fers

, yac

hts,

mot

or b

oats

)• A

ctiv

ities

dur

ing

boat

ing

(eg.

scub

a di

ving

, w

ater

skiin

g, fi s

hing

, rac

ing)

• Lim

itatio

n of

act

iviti

es t

o ar

eas

away

from

of

ftak

es• N

o bo

at la

unch

ing

poin

ts w

ithin

cat

chm

ent

• Lau

nchi

ng p

oint

s di

stan

t to

offt

akes

and

se

aled

• Man

agem

ent

of b

oats

and

faci

litie

s re

quir

ed o

n bo

ats

• Res

tric

tion

on t

ypes

of b

oats

use

d (e

g to

sa

iling

boa

ts w

ithou

t fu

el).

• Ran

ger

patr

ols

• Rev

iew

info

rmat

ion

on b

oatin

g, in

clud

ing

occu

rren

ce o

f spi

lls

and

exte

nt t

o w

hich

sew

age

is m

anag

ed• P

rohi

bit

mot

oris

ed b

oats

to

redu

ce t

he r

isk

of p

etro

leum

spi

lls• R

estr

ict

boat

ing

in s

ome

area

s (e

g. ne

ar s

pillw

ay, n

ear

offt

akes

)• B

oatin

g cl

ub o

r pe

rmit

syst

em• C

onst

ruct

clu

bhou

se o

utsi

de c

atch

men

t• S

eale

d ac

cess

roa

d an

d la

unch

ing

poin

t• D

ay a

cces

s on

ly• S

ubsi

dise

dev

elop

men

t of

nea

rby

stor

age

not

used

for

wat

er

supp

ly p

urpo

ses

Four

-whe

el

driv

ing

and

rally

dri

ving

• Mic

robi

olog

ical

co

ntam

inat

ion

- f

rom

hu

man

was

te• C

hem

ical

con

tam

inat

ion

-

fro

m fu

el a

nd o

ils• T

urbi

dity

- f

rom

ero

sion

of

tra

cks,

dist

urba

nce

of

sedi

men

t in

str

eam

s

• Num

ber

of v

ehic

les

invo

lved

• Typ

e of

use

r (e

g. re

crea

tion,

ral

ly e

vent

)• L

evel

of c

ontr

ol o

ver

activ

ity• L

ocat

ion

of r

oads

• Nat

ure

of r

oads

(se

aled

or

unse

aled

)• L

ocat

ion

of fu

el d

epot

s, ta

nker

rou

tes,

form

of f

uel s

tora

ges

• Alte

rnat

ive

supp

ly d

urin

g m

ajor

4W

D/r

ally

ev

ents

• Pro

visi

on o

f spe

cial

ly d

esig

ned

trac

ks (

away

fr

om w

ater

cour

ses,

with

gra

vel c

over

to

prev

ent

eros

ion)

• Pre

vent

ive

mea

sure

s ov

er r

efue

lling

are

as

(des

igna

ted

area

s w

ith s

pill

cont

ainm

ent,

away

from

wat

er)

• Res

tric

t ac

cess

to

only

com

petin

g ve

hicl

es

and

supp

ort

team

s

• Rev

iew

occ

urre

nce

of 4

WD

ing

in c

atch

men

t• R

estr

ict

or p

rohi

bit

recr

eatio

nal 4

WD

ing

or r

ally

dri

ving

• Dev

elop

and

rev

iew

an

envi

ronm

enta

l man

agem

ent

plan

for

each

ral

ly e

vent

• No

prac

tice

even

ts t

o be

hel

d• N

o ve

hicl

e m

aint

enan

ce w

ithin

the

cat

chm

ent

• Roa

d m

aint

enan

ce t

o be

car

ried

out

imm

edia

tely

aft

er a

n ev

ent

• Per

mit

even

ts o

nly

in d

rier

tim

es o

f the

yea

r• M

emor

andu

m o

f Und

erst

andi

ng w

ith r

ally

org

anis

ers

and

4WD

cl

ubs

Picn

ics

in

desi

gnat

ed

area

s

• Mic

robi

olog

ical

co

ntam

inat

ion

-

from

lit

ter

and

hum

an w

aste

• Att

ract

ion

of fe

ral a

nim

als

(ie w

aste

s, er

osio

n, d

ead

anim

als)

• Dra

inag

e fr

om p

icni

c ar

eas

into

res

ervo

ir• F

eral

ani

mal

pop

ulat

ion

and

rela

tions

hips

to

use

of p

icni

c ar

eas

• Num

bers

and

sea

sona

lity

of p

icni

cker

s • L

ocat

ion

and

num

ber

of p

icni

c ar

eas

avai

labl

e• I

ncid

ence

of h

uman

was

tes

and

erod

ed

shor

elin

e

• Pro

visi

on o

f ade

quat

e w

aste

faci

litie

s• L

imita

tion

of a

ctiv

ities

aw

ay fr

om

wat

erco

urse

s• S

hoot

ing

and

baiti

ng o

f fer

al a

nim

als

• Ran

ger

patr

ols

• Day

acc

ess

only

• Kee

p pi

cnic

site

s aw

ay fr

om o

r do

wns

trea

m o

f offt

akes

• Sel

ect

site

s w

here

cat

ch d

rain

s an

d fe

nces

pre

vent

acc

ess

to

rese

rvoi

r

Swim

min

g• M

icro

biol

ogic

al

cont

amin

atio

n -

fr

om

litte

r an

d hu

man

was

te• T

urbi

dity

-

fro

m

shor

elin

e di

stur

banc

e

• Num

bers

and

sea

sona

lity

of s

wim

mer

s• S

wim

min

g si

tes

avai

labl

e• I

ncid

ence

of h

uman

was

tes

and

erod

ed

shor

elin

e

• Res

tric

tion

of s

ites

avai

labl

e fo

r sw

imm

ing

• Lim

itatio

n of

act

iviti

es a

way

from

offt

akes

• Ran

ger

patr

ols

• Pro

hibi

t sw

imm

ing

with

in c

atch

men

t• P

ublic

edu

catio

n ca

mpa

ign

usin

g si

gnag

e an

d pa

trol

s


29

Oth

er

rela

ted

Fac

t S

he

ets

: •

7. L

and

Use

with

in C

atch

men

ts•

8. R

oads

with

in C

atch

men

ts•

9. U

rban

Dev

elop

men

t w

ithin

Cat

chm

ents

Use

ful

Lit

era

ture

: •

Ref

er A

ppen

dice

s B,

C•

Stir

ling

Dam

Cat

chm

ent A

rea

Dra

ft W

ater

Sou

rce

Prot

ectio

n Pl

an, W

ater

and

Riv

ers

Com

mis

sion

(W

A),

Nov

embe

r 19

99.

• Ta

sman

ian

Wild

erne

ss W

orld

Her

itage

Are

a M

anag

emen

t Pl

an. T

asm

ania

Par

ks a

nd W

ildlif

e Se

rvic

e, T

asm

ania

n G

over

nmen

t, 19

99.

Use

ful

We

bsi

tes:

• ht

tp://

ww

w.s

wrc

b.ca

.gov

/gen

eral

/pub

licat

ions

/inde

x.ht

ml


30

4. I

nd

ust

rial

De

velo

pm

en

t w

ith

in C

atch

me

nts

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Indu

stri

al

chem

ical

was

te

disc

harg

e

cont

amin

atin

g gr

ound

wat

er,

surf

ace

wat

er

• Che

mic

al c

onta

min

atio

n

- n

itrat

es a

nd p

hosp

hate

s, ph

enol

ics,

heav

y m

etal

s, pe

trol

eum

hyd

roca

rbon

s, en

docr

ine

disr

upto

rs• C

yano

bact

eria

tox

ins

• Tas

te a

nd o

dour

co

mpo

unds

- f

rom

alg

ae

• Num

ber

and

prox

imity

of i

ndus

tria

l pl

ants

• Typ

es o

f pro

cess

es a

nd c

hem

ical

s us

ed• M

etho

d of

was

te d

ispo

sal

• Vol

ume

of w

aste

• Pre

caut

iona

ry m

easu

res

impl

emen

ted

by in

dust

ry

• Res

tric

tion

of a

llow

able

dis

char

ges

• Res

tric

tion

of a

llow

able

indu

stri

al p

roce

sses

• Was

te m

anag

emen

t pl

ans

• Rev

iew

loca

tion

and

type

of i

ndus

try

and

pote

ntia

l for

re

leas

es o

f che

mic

als

to r

ecei

ving

wat

ers

• Ide

ntify

any

his

tori

cal r

elea

se o

ccur

renc

es (

eg E

PA)

• Req

uire

was

te m

anag

emen

t pl

ans

to b

e de

velo

ped

whi

ch

clea

rly

and

adeq

uate

ly a

ddre

ss w

ater

qua

lity

issu

es• E

nsur

e th

at b

est

prac

tice

was

te m

anag

emen

t pl

ans

and

prac

tices

are

bei

ng fo

llow

ed b

y vi

sual

insp

ectio

n an

d lia

ison

w

ith in

dust

ry

• Enc

oura

ge d

evel

opm

ent

of p

roce

sses

and

wor

k pr

actic

es

whi

ch r

educ

e w

aste

out

put

• Enc

oura

ge r

emov

al o

f was

te e

ntir

ely

from

the

cat

chm

ent

• Opp

ose

new

indu

stri

al d

evel

opm

ent

and

enco

urag

e re

mov

al o

f exi

stin

g de

velo

pmen

t• E

ncou

rage

indu

stry

aw

aren

ess

of w

ater

qua

lity

issu

esC

hem

ical

sp

ills

-

at

indu

stri

al

site

s or

dur

ing

tran

spor

t

• Che

mic

al c

onta

min

atio

n

- fu

el p

etro

leum

- hy

droc

arbo

ns,

-

PCB’

s /w

aste

oils

-

cyan

ides

(m

etal

s pr

oces

sing

)

- pl

astic

iser

s,

-her

bici

des/

pest

icid

es -

bul

k fl

uori

des

-

fert

ilise

r

• Num

ber

of in

dust

rial

pla

nts

• Typ

es o

f che

mic

als

used

and

vol

ume

pres

ent

on s

ite a

nd in

tra

nspo

rt• M

etho

d of

che

mic

als

tran

spor

t (r

oad,

ra

il, pi

pelin

e)• F

requ

ency

of c

hem

ical

s tr

ansp

ort

• Loc

atio

n of

tra

nspo

rt r

oute

and

pl

ant

with

res

pect

to

wat

erw

ays

and

rese

rvoi

rs• R

oad

acci

dent

his

tory

with

in c

atch

men

t

• Ind

ustr

ial d

evel

opm

ent

only

in h

eadw

ater

s or

low

rai

nfal

l are

as• R

estr

ictio

n of

allo

wab

le in

dust

rial

pro

cess

es

and

chem

ical

s• T

erm

inat

e ab

stra

ctio

n at

raw

wat

er o

fftak

e• B

unde

d ar

eas,

catc

h dr

ains

, and

con

tain

men

t da

ms

• Inc

iden

t an

d em

erge

ncy

resp

onse

pla

ns

• Raw

wat

er b

iolo

gica

l mon

itori

ng fo

r in

dust

rial

spi

lls• R

oads

to

be w

ell a

way

from

wat

erco

urse

s w

ithou

t cr

ossi

ngs

• Pro

hibi

tion

of t

rans

port

of n

omin

ated

goo

ds

alon

g sp

ecifi

c ro

ads

• Reg

iste

r of

acc

iden

ts r

ecor

ding

typ

e an

d lo

catio

n of

spi

ll

• Rev

iew

indu

stry

for

spill

pot

entia

l as

abov

e• P

ursu

e ex

clus

ion

of u

se o

f roa

ds fo

r tr

ansp

ort

of c

erta

in

haza

rdou

s go

ods

• Req

uire

em

erge

ncy

resp

onse

pla

ns t

o be

dev

elop

ed

whi

ch c

lear

ly a

nd a

dequ

atel

y ad

dres

s w

ater

qua

lity

issu

es,

pred

omin

antly

in t

rapp

ing

or m

inim

isin

g th

e sp

ill.

• Mem

oran

dum

of U

nder

stan

ding

with

loca

l em

erge

ncy

serv

ices

• Aud

it sa

fety

pro

cedu

res

for

indu

stri

al c

hem

ical

sto

rage

and

tr

ansp

ort

• Mem

oran

dum

of U

nder

stan

ding

or

mem

bers

hip

of

HA

ZM

AT t

eam

• Est

ablis

h ca

tch

drai

ns a

nd c

onta

inm

ent

dam

s w

here

roa

ds

cros

s or

pas

s ne

ar w

ater

cour

ses

or r

eser

voir

s

Fire

at

indu

stri

al s

ites

• Che

mic

al c

onta

min

atio

n

- fr

om s

prin

kler

s an

d fi r

e ho

se r

unof

f, sp

ills

from

ch

emic

al s

tora

ges

• Typ

es o

f ind

ustr

ial p

lant

s• V

olum

es o

f haz

ardo

us c

hem

ical

s on

site

• Fir

e de

tect

ion

and

supp

ress

ion

syst

ems

in p

lace

• Res

tric

tion

of a

llow

able

indu

stri

al p

roce

sses

an

d ch

emic

als

• Inc

iden

t an

d em

erge

ncy

resp

onse

pla

ns

• See

sug

gest

ions

for

Che

mic

al S

pills

abo

ve

Min

ing

activ

ities

an

d w

aste

s• T

urbi

dity

- f

rom

ero

sion

an

d w

asho

ff fr

om d

ust

supp

ress

ion

syst

ems

• Che

mic

al c

onta

min

atio

n -

fr

om p

etro

chem

ical

s an

d ot

her

mat

eria

ls b

eing

min

ed

• Sca

le o

f min

ing

• Typ

e of

min

ing

(eg.

open

cut

)• M

iner

als

bein

g m

ined

and

ext

ract

ed• M

etho

d of

tra

nspo

rt• P

oten

tial f

or a

cid

min

e dr

aina

ge

• Bun

ded

area

s, ca

tch

drai

ns, a

nd c

onta

inm

ent

dam

s• R

ehab

ilita

tion

of d

isus

ed a

reas

• Rev

iew

occ

urre

nce

and

natu

re o

f min

ing

in t

he a

rea

and

its

prox

imity

to

rece

ivin

g w

ater

s• C

onsu

lt w

ith r

elev

ant

gove

rnm

ent

depa

rtm

ent

(eg

Min

es

Dep

artm

ent)

to

dete

rmin

e po

tent

ial f

or m

inin

g in

the

fu

ture


31

Oth

er

rela

ted

Fac

t S

he

ets

: •

1. A

gric

ultu

re w

ithin

Cat

chm

ents

• 2.

Env

iron

men

tal H

azar

ds w

ithin

Cat

chm

ents

• 10

. Alg

al B

loom

s w

ithin

Res

ervo

irs

Use

ful

Lit

era

ture

:•

Koe

hnke

n L.

, 199

6 M

acqu

arie

Har

bour

- K

ing

Riv

er S

tudy

, Tas

man

ian

Gov

ernm

ent,

Hob

art,

Tasm

ania

.•

Rib

audo

, M. O

, R

. D. H

oran

, and

M. E

. Sm

ith. 1

999.

Eco

nom

ics

of w

ater

qua

lity

prot

ectio

n fr

om n

onpo

int

sour

ces:

The

ory

and

prac

tice.

Res

ourc

e Ec

onom

ics

Div

isio

n, E

cono

mic

Res

earc

h Se

rvic

e, U

.S.

Dep

artm

ent

of A

gric

ultu

re. A

gric

ultu

ral E

cono

mic

Rep

ort

No.

782

• D

irec

tive

2000

/60/

EC o

f the

Eur

opea

n Pa

rlia

men

t an

d of

the

Cou

ncil

esta

blis

hing

a fr

amew

ork

for

the

Com

mun

ity a

ctio

n in

the

fi el

d of

wat

er p

olic

y, O

ffi ci

al Jo

urna

l (O

J L 3

27),

2000

. (r

efer

UR

L: h

ttp:

//eur

opa.

eu.in

t/eu

r-le

x/en

/lif/d

at/2

000/

en_3

00L0

060.

htm

l)


32

5. F

ore

stry

wit

hin

Cat

chm

en

tsS

ou

rce

of

Haz

ard

/Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Tim

ber

harv

estin

g, tr

ee e

stab

lishm

ent

and

mai

nten

ance

• Tur

bidi

ty - fr

om e

rosi

on

and

tru

ck a

nd m

achi

nery

ac

cess

on

unse

aled

roa

ds• C

hem

ical

con

tam

inat

ion

-

pet

roch

emic

als

from

fu

el s

pill,

fert

ilise

r, pe

stic

ide

and

herb

icid

e

• Pro

xim

ity o

f har

vest

ing

area

s to

w

ater

way

s• A

rea

of p

lant

atio

ns w

ithin

cat

chm

ent

• Har

vest

ing

prac

tices

- s

elec

tive

or

clea

r fe

lling

• Mac

hine

ry n

umbe

rs• S

lope

and

soi

l typ

e of

affe

cted

land

• Use

of b

uffe

r zo

nes

betw

een

harv

est

area

s an

d w

ater

way

s• F

ores

try

man

agem

ent

plan

s in

clud

ing

equi

pmen

t m

aint

enan

ce a

nd o

pera

tion

plan

s

• Rev

iew

logg

ing

plan

s an

d pr

actic

es, a

nd in

spec

t pr

otec

tion

mea

sure

s on

the

gro

und

• Ens

ure

fore

stry

man

agem

ent

plan

s ad

dres

s w

ater

qua

lity

issu

es

incl

udin

g ro

ad a

nd e

quip

men

t m

aint

enan

ce, f

uel s

tora

ge a

nd h

andl

ing,

fert

ilise

r, pe

stic

ide

and

herb

icid

e us

e• E

nsur

e fo

rest

buf

fer

zone

s ex

ist

betw

een

all h

arve

st a

nd

esta

blis

hmen

t ar

eas

and

wat

erco

urse

s

Oth

er

rela

ted

Fac

t S

he

ets

: •

4. In

dust

rial

Dev

elop

men

t w

ithin

Cat

chm

ents

• 8.

Roa

ds w

ithin

Cat

chm

ents

Use

ful

Lit

era

ture

:•

Ano

nym

ous,

Cod

e of

For

est

Prac

tices

for T

imbe

r Pr

oduc

tion

- R

evis

ion

No.

2, D

ept.

of N

atur

al R

esou

rces

and

Env

iron

men

t (V

ic.),

199

6.•

Hat

ton,

T. a

nd D

awes

, W. T

he im

pact

of t

ree

plan

ting

in t

he M

urra

y-D

arlin

g ba

sin:

the

use

of t

he T

OPO

G_I

RM

hyd

roec

olog

ical

mod

el in

tar

getin

g tr

ee p

lant

ing

site

s in

cat

chm

ents

, CSI

RO, 1

991.


33

6. W

aste

Man

age

me

nt

/ W

aste

wat

er

Fac

ilit

ies

wit

hin

Cat

chm

en

tsS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Was

tew

ater

faci

litie

s/di

scha

rge

(tre

atm

ent

plan

ts,

was

te p

ipel

ines

, sep

tic

tank

s)

• Nor

mal

, dis

infe

cted

• Mic

robi

olog

ical

co

ntam

inat

ion

• C

hem

ical

con

tam

inat

ion

-

disi

nfec

tion

bypr

oduc

ts,

nutr

ient

s, am

mon

ia,

orga

nics

, end

ocri

ne

disr

upto

rs• C

yano

bact

eria

tox

ins

• Tas

te a

nd o

dour

co

mpo

unds

• Vol

ume

of n

orm

al d

isch

arge

com

pare

d w

ith n

orm

al r

iver

fl ow

or

rese

rvoi

r vo

lum

es• M

icro

bial

det

ectio

n in

effl

uent

• Pho

spho

rus

rem

oval

and

var

iatio

n in

co

ncen

trat

ion

• Nitr

ogen

rem

oval

and

nitr

ifi ca

tion

(am

mon

ia c

once

ntra

tion)

• Re-

use

of w

aste

wat

er d

isch

arge

• Zer

o di

scha

rge

in s

umm

er• S

pray

irri

gatio

n on

fore

sts

with

ca

tchd

rain

s• P

ipe

disc

harg

e ou

t of

wat

er

supp

ly c

atch

men

t• D

isch

arge

to

wet

land

s• U

V d

isin

fect

ion

of d

isch

arge

• Filt

ratio

n

• Rev

iew

dis

char

ges

from

was

tew

ater

faci

litie

s in

cat

chm

ent,

incl

udin

g qu

ality

and

var

iatio

ns in

qua

lity

and

inci

dent

and

em

erge

ncy

resp

onse

pla

ns• A

im fo

r to

tal r

euse

of n

orm

al w

aste

wat

er d

isch

arge

• Enc

oura

ge p

hosp

horu

s re

duct

ion

to <

2m

g/ L

• Ins

tall

UV

dis

infe

ctio

n of

dis

char

ge a

nd c

heck

for

viab

le m

icro

bes

• Req

uire

dri

nkin

g w

ater

to

be fu

lly fi

ltere

d

Was

tew

ater

faci

litie

s/di

scha

rge

• Ove

rfl o

ws

due

to:

- infi l

trat

ion

- bu

rst

pipe

s-

trea

tmen

t fa

ilure

• Cro

ss c

onne

ctio

ns

• Mic

robi

olog

ical

co

ntam

inat

ion

• C

hem

ical

con

tam

inat

ion

-

disi

nfec

tion

bypr

oduc

ts,

nutr

ient

s, am

mon

ia,

orga

nic,

endo

crin

e di

srup

tors

• Cya

noba

cter

ia t

oxin

s• T

aste

and

odo

ur

com

poun

ds

• Vol

umes

dis

char

ged

com

pare

d w

ith

norm

al r

iver

fl ow

or

rese

rvoi

r vo

lum

es• Q

ualit

y of

effl

uent

(eg

. mic

robe

s, nu

trie

nts,

orga

nics

, etc

.)• D

ilutio

n of

was

te in

riv

er, w

ater

way

or

rese

rvoi

r• D

ispe

rsio

n of

was

te in

riv

er• S

hort

cir

cuit

pote

ntia

l acr

oss

rese

rvoi

r• F

easi

bilit

y of

cea

sing

use

of w

ater

so

urce

tem

pora

rily

in e

mer

genc

y

• Ove

rfl o

w b

asin

at

was

tew

ater

pl

ant

• Not

ifi ca

tion

of d

owns

trea

m

wat

er a

bstr

acte

rs• I

nspe

ctio

n an

d pr

essu

re/ l

eak

test

ing

for

all m

ajor

tra

nsfe

r pi

pes

at p

lant

• Lev

el a

larm

s on

ove

rfl o

w

stru

ctur

es• F

iltra

tion

• Rev

iew

rec

ords

of o

verfl

ow

s an

d cr

oss

conn

ectio

ns r

elat

ing

to

was

tew

ater

faci

litie

s• P

rovi

de le

vel a

larm

s on

ove

rfl o

w s

truc

ture

s• U

nder

take

reg

ular

tes

ting

of p

ipel

ines

and

mea

ns t

o de

tect

bre

aks

(eg.

low

fl ow

sw

itch

at in

let

and

outle

t)• P

rose

cute

ille

gal s

torm

wat

er c

onne

ctio

ns• E

nsur

e ov

erfl o

w b

asin

s ar

e th

e co

rrec

t si

ze• C

ompl

ete

time

of t

rave

l / d

ispe

rsio

n st

udie

s to

defi

ne

impa

ct o

f po

tent

ial o

verfl

ow

s• E

stab

lish

inci

dent

and

em

erge

ncy

resp

onse

pro

cedu

res

to c

onta

in

overfl o

w a

nd n

otify

wat

er a

bstr

acte

rs d

owns

trea

m• R

equi

re d

rink

ing

wat

er t

o be

fi lte

red

Was

tew

ater

faci

litie

s/di

scha

rge

• Cro

ss c

onta

min

atio

n of

was

tew

ater

tr

eatm

ent

plan

t la

goon

s an

d dr

inki

ng

wat

er r

eser

voir

s fr

om w

ater

bird

s

• Mic

robi

olog

ical

co

ntam

inat

ion

• Nut

rien

ts• C

yano

bact

eria

tox

ins

• Obs

erve

d bi

rd t

rans

fers

bet

wee

n la

goon

s an

d re

serv

oirs

• Tes

t bi

rds

for

pres

ence

of v

irus

es a

nd

mic

robi

al p

atho

gens

• Alg

al im

pact

s ob

serv

ed in

res

ervo

ir

due

to b

ird

drop

ping

s

• Max

imum

sep

arat

ion

betw

een

lago

ons

and

rese

rvoi

rs• C

over

res

ervo

irs

or a

naer

obic

la

goon

s• D

isin

fect

ion

of r

eser

voir

(in

let

and

outle

t)• F

iltra

tion

of d

rink

ing

wat

er

• Rev

iew

pre

senc

e of

bir

ds a

nd t

heir

mov

emen

ts o

n dr

inki

ng w

ater

re

serv

oir

and

at o

ther

wat

er b

odie

s• M

axim

ise

buffe

r zo

ne b

etw

een

lago

ons

and

rese

rvoi

rs w

here

po

ssib

le• C

over

res

ervo

irs

• Cov

er a

naer

obic

lago

ons

Was

te M

anag

emen

t Fa

cilit

ies

• Lan

dfi ll

• Was

te r

ecyc

ling

cent

res

• Med

ical

was

te

• Mic

robi

olog

ical

co

ntam

inat

ion

-fr

om

bird

dro

ppin

gs a

nd

landfi l

l was

te• C

yano

bact

eria

tox

ins

• Bir

d po

pula

tions

roo

stin

g at

wat

er

supp

ly r

eser

voir

• Dis

infe

ctio

n re

liabi

lity

and

exte

nt (

inle

t an

d ou

tlet)

• Det

ectio

n of

mic

robi

olog

ical

co

ntam

inat

ion

prio

r to

dis

infe

ctio

n• A

lgal

impa

cts

obse

rved

in r

eser

voir

du

e to

bir

d dr

oppi

ngs

• Cov

er w

ater

sup

ply

rese

rvoi

r• M

axim

um s

epar

atio

n be

twee

n op

en la

nd fi

ll an

d w

ater

sup

ply

rese

rvoi

r• C

onve

rt o

pen

landfi l

l to

cove

red

was

te t

rans

fer

cent

res

• Rev

iew

loca

tion

of w

aste

man

agem

ent

faci

litie

s an

d m

axim

ise

buffe

r be

twee

n la

ndfi l

l and

wat

er s

uppl

y re

serv

oirs

whe

re p

ossi

ble

(>10

km

is p

refe

rabl

e)• C

onve

rt la

ndfi l

l to

cove

red

was

te t

rans

fer

stat

ions

• Cov

er w

ater

sup

ply

rese

rvoi

r


34

Oth

er

rela

ted

Fac

t S

he

ets

: •

3. H

uman

Acc

ess

to C

atch

men

ts•

4. In

dust

rial

Dev

elop

men

t w

ithin

Cat

chm

ents

• 8.

Roa

ds w

ithin

Cat

chm

ents

• 9.

Urb

an D

evel

opm

ent

with

in C

atch

men

ts•

10. A

lgal

Blo

oms

with

in R

eser

voir

s

Use

ful

Lit

era

ture

: •

Dill

on, P

. Wat

er r

euse

in A

ustr

alia

, Cur

rent

Sta

tus,

Proj

ectio

ns a

nd R

esea

rch,

Wat

er R

ecyc

ling

Aus

tral

ia, D

illon

P.J.

, (ed

.) C

SIRO

and

AW

A, 2

000.

Use

ful

We

bsi

tes:

• ht

tp://

euro

pa.e

u.in

t/co

mm

/env

iron

men

t/sl

udge

/


35

7. L

and

Use

wit

hin

Cat

chm

en

tsS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Div

erse

land

use

s w

ithin

cat

chm

ent

• Hig

hly

vari

able

wat

er

qual

ity (

espe

cial

ly

duri

ng/a

fter

sto

rm

even

ts)

• Var

iabl

e co

lour

• Var

iabl

e tu

rbid

ity

• Nut

rien

ts, p

H a

nd

alka

linity

• Mic

robi

olog

ical

co

ntam

inat

ion

• Man

y di

ffere

nt la

nd u

ses

mak

e m

anag

emen

t di

ffi cu

lt

• Var

ious

land

use

s ca

n co

mbi

ne t

o ca

use

unfo

rese

en h

azar

ds

• Tre

nds

to la

nd u

se

• Buf

fer

stri

ps a

long

cre

eks

to li

mit

eros

ion

impa

cts

• Reg

iona

l Lan

d Pr

otec

tion

Plan

s to

ov

erlin

e lim

it th

e ra

nge

in la

nd u

se

• Map

ping

of a

ctua

l lan

d us

e an

d pr

esen

tatio

n of

rem

aini

ng s

trea

m

• Inc

entiv

es t

o el

imin

ate

inap

prop

riat

e la

nd u

ses

• Red

uce

rang

e of

land

use

s

• Est

ablis

h ex

tens

ive

cree

k ri

pari

an s

trip

s

• Con

trol

ext

ent

of fa

rm d

ams

and

grou

ndw

ater

use

Inap

prop

riat

e la

nd

use

prot

ectio

n re

quir

emen

ts

• Unp

redi

ctab

le c

hang

es

in w

ater

qua

lity

espe

cial

ly d

urin

g st

orm

ev

ents

• See

mos

t ha

zard

s in

ot

her

Fact

She

ets

1-10

• Ran

ge o

f act

iviti

es a

llow

able

with

one

la

nd u

se t

ype

• Ran

ge o

f lan

d us

es

• Lev

el o

f aut

hori

ty g

iven

to

man

age

catc

hmen

t

• Lev

el o

f reg

ulat

ion

of la

nd u

se z

onin

g

• Abi

lity

to c

ontin

uous

ly m

onito

r w

ater

qu

ality

and

cea

se d

iver

sion

s fo

r w

ater

su

pply

pur

pose

s

• Tre

nds

in la

nd u

se (

eg. d

airi

es r

epla

ced

by

vitic

ultu

re)

• Ext

ent

of fa

rm d

ams

and

ripa

rian

str

ips

• Reg

ular

(5

year

) re

view

and

upd

atin

g of

pro

tect

ion

requ

irem

ents

• Upd

atin

g of

land

use

GIS

dat

a ba

ses

ever

y 5

to 1

0 ye

ars

• Est

ablis

h C

odes

of P

ract

ice

for

criti

cal l

and

uses

• Off

stre

am s

tora

ge t

o bu

ffer

vari

atio

ns a

nd c

ompr

ehen

sive

wat

er

trea

tmen

t do

wns

trea

m o

f div

ersi

on

poin

t fr

om c

atch

men

t

• Red

uce

rang

e of

land

use

s

• Whe

re p

ossi

ble

dive

rt o

r ce

ase

use

duri

ng s

torm

eve

nt fi

rst

fl ush

es a

nd h

igh

turb

idity

per

iods

• Foc

us o

n la

nd u

ses

gene

ratin

g hi

gh m

icro

biol

ogic

al

cont

amin

atio

n (e

g. pi

gger

ies,

dair

ies)

and

tur

bidi

ty /n

utri

ents

(e

g. po

tato

cro

ppin

g, m

acad

amia

s)

Oth

er

rela

ted

Fac

t S

he

ets

: •

1– 9

. See

oth

er fa

ct s

heet

s on

cat

chm

ent-

rela

ted

topi

cs


36

8. R

oad

s w

ith

in C

atch

me

nts

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Seal

ed/u

nsea

led

ro

ads

• Tur

bidi

ty -

from

er

osio

n• L

evel

of r

oad

usag

e• P

urpo

se o

f usa

ge• L

ocat

ion

of r

oads

rel

ativ

e to

res

ervo

ir

and

stre

ams

and

offt

ake

• Typ

es o

f veh

icle

s• T

ypes

and

con

ditio

ns o

f roa

ds

• Spe

ed li

mits

• Roa

d m

aint

enan

ce• S

igna

ge• P

ublic

edu

catio

n

• Rev

iew

roa

d ne

twor

k a

nd c

lose

unn

eces

sary

roa

ds, e

spec

ially

tho

se

clos

e to

res

ervo

irs,

ensu

ring

rec

reat

iona

l nee

ds a

re c

onsi

dere

d.• R

evie

w r

oad

man

agem

ent

prac

tices

and

dev

elop

a m

anag

emen

t pl

an

so r

isk

to w

ater

qua

lity

is m

inim

ised

Eros

ion

of r

oadw

ay

or r

oad

shou

lder

(r

unof

f fro

m r

oad)

• Tur

bidi

ty

• Num

bers

of v

ehic

les

• Typ

es /

wei

ghts

of v

ehic

les

(eg.

4WD

, se

dan,

logg

ing

truc

k)• L

ocat

ion

of r

oads

rel

ativ

e to

str

eam

s, re

serv

oir

and

offt

akes

• Con

ditio

n of

roa

dway

and

roa

d sh

ould

er• S

oil t

ype

• Roa

d dr

aina

ge s

yste

m, e

xist

ence

of

sedi

men

t tr

aps

• Spe

ed li

mits

• Veh

icle

wei

ght

limits

• Roa

d m

aint

enan

ce /

road

sea

ling

• Sed

imen

t tr

aps

on r

oad

drai

nage

pa

ths

• See

abo

ve

Spill

s of

haz

ardo

us

mat

eria

ls• C

hem

ical

co

ntam

inat

ion

-

from

pet

roch

emic

als

and

othe

r ch

emic

als

• Lev

el o

f roa

d us

age

• Lev

el o

f usa

ge o

f roa

d fo

r ch

emic

al

tran

spor

t

• Sed

imen

t tr

aps

on r

oad

drai

nage

pa

ths

• Con

duct

a r

isk

asse

ssm

ent

surv

ey o

f the

use

of r

oads

with

in t

he

catc

hmen

t fo

r fu

el a

nd c

hem

ical

tra

nspo

rt• E

nsur

e in

cide

nt a

nd e

mer

genc

y re

spon

se p

roce

ss is

in p

lace

and

co

ordi

nate

d w

ith lo

cal e

mer

genc

y se

rvic

es

Oth

er

rela

ted

Fac

t S

he

ets

: •

3. H

uman

Acc

ess

to C

atch

men

ts•

4. In

dust

rial

Dev

elop

men

t w

ithin

Cat

chm

ents

• 7.

Lan

d U

se w

ithin

Cat

chm

ents

• 9.

Urb

an D

evel

opm

ent

with

in C

atch

men

ts

Use

ful

Lit

era

ture

:•

Dra

pper

, D., T

omlin

son,

R. a

nd P

. Will

iam

s (2

000)

. Pol

luta

nt C

once

ntra

tions

in R

oad

Run

off:

Sout

heas

t Q

ueen

slan

d C

ase

Stud

y. Jo

urna

l of E

nviro

nmen

tal E

ngin

eerin

g, AS

CE, V

ol.1

26, I

ssue

4, p

p. 3

13-3

20.


37

9. U

rban

De

velo

pm

en

t w

ith

in C

atch

me

nts

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Stor

mw

ater

• Mic

robi

olog

ical

co

ntam

inat

ion

- fr

om li

tter

, pe

t w

aste

• Tur

bidi

ty

- f

rom

in

crea

sed

runo

ff ve

loci

ties

and

fast

er fl

ow r

espo

nse

times

• Che

mic

al c

onta

min

atio

n -

from

pet

roch

emic

als

• Num

ber

of h

ouse

s an

d po

pula

tion

size

• Sta

te o

f roa

ds w

ithin

urb

an a

rea

• Typ

e an

d ca

paci

ty o

f sto

rmw

ater

dr

aina

ge s

yste

m• A

bilit

y to

div

ert

stor

mw

ater

to

dow

nstr

eam

of r

eser

voir

or

out

of

catc

hmen

t co

mpl

etel

y

• Litt

er t

raps

in s

torm

wat

er p

its• S

edim

ent

trap

s• B

uffe

r zo

nes

arou

nd r

eser

voir

• Rev

iew

occ

urre

nce

of s

torm

wat

er d

isch

arge

s to

rec

eivi

ng

wat

ers

• Mon

itor

qual

ity o

f wat

er w

here

dis

char

ges

are

sign

ifi ca

nt in

qu

antit

y• R

evie

w a

ctiv

ities

with

in c

atch

men

t to

det

erm

ine

pote

ntia

l so

urce

s of

pol

lutio

n of

sto

rmw

ater

Fire

- e

g. fr

om

elec

tric

al c

able

s, ga

s fa

cilit

ies,

appl

ianc

es

• Tur

bidi

ty -

fro

m

part

icul

ate

fallo

ut a

nd

resi

dual

was

te• C

hem

ical

con

tam

inat

ion

– fi r

e re

tard

ant

chem

ical

s

• Exi

sten

ce o

f fue

l and

oth

er

com

bust

ible

s an

d fl a

mm

able

s in

are

a• P

roxi

mity

to

rece

ivin

g w

ater

and

po

tent

ial f

or r

un o

ff to

rea

ch w

ater

• Ale

rt fi

re a

utho

rity

• M

easu

res

to r

estr

ict fi r

ewat

er

from

ent

erin

g re

ceiv

ing

wat

ers

• Rev

iew

act

iviti

es a

ssoc

iate

d w

ith u

rban

dev

elop

men

t w

ith

resp

ect

to fi

re p

oten

tial a

nd p

ollu

tion

• Con

sult

with

loca

l fi r

e au

thor

ity• P

ublic

aw

aren

ess

and

educ

atio

n pr

ogra

ms

Oth

er

rela

ted

Fac

t S

he

ets

: •

4. In

dust

rial

Dev

elop

men

t w

ithin

Cat

chm

ents

• 6.

Was

te M

anag

emen

t / W

aste

wat

er F

acili

ties

with

in C

atch

men

ts•

7. L

and

Use

with

in C

atch

men

ts•

8. R

oads

with

in C

atch

men

ts

Use

ful

Lit

era

ture

: •

Ref

er A

ppen

dice

s B,

C•

Dra

nger

t, J.

Goi

ng s

mal

l whe

n th

e ci

ty g

row

s? M

anag

emen

t op

tions

for

the

21st

cen

tury

. In

“Wat

er -

the

wor

ld’s

mos

t im

port

ant

reso

urce

”, ab

stra

cts,

Xth

Wor

ld W

ater

Con

gres

s, IW

RA

, 12t

h -1

6th

Mar

ch, 2

000.

Use

ful

We

bsi

tes:

• ht

tp://

euro

pa.e

u.in

t/co

mm

/env

iron

men

t/w

ater

/wat

er-fr

amew

ork/

over

view

.htm

l


38

10

. Alg

al B

loo

ms

wit

hin

Re

serv

oir

sS

ou

rce

of

Haz

ard

/Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Alg

al b

loom

s •

Che

mic

al

cont

amin

atio

n

-or

gani

cs (

bact

eria

re

grow

th)

• C

yano

bact

eria

tox

ins

• Ta

ste

and

odou

r co

mpo

unds

• C

olou

r•

Dis

infe

ctio

n By

prod

ucts

aft

er

disi

nfec

tion

• Bl

ocke

d fi l

ters

• Fr

eque

ncy

and

spec

ies

of a

lgal

blo

oms

• Ex

tent

of p

oor

tast

e an

d od

our

• Sp

ecie

s of

alg

ae b

lock

ing fi l

ters

•

Exte

nt o

f mon

itori

ng e

mpl

oyed

to

pred

ict

onse

t of

blo

oms

• Fr

eque

ncy

of c

oppe

r su

lpha

te d

osin

g•

Seve

rity

of r

eser

voir

che

mic

al

stra

tifi c

atio

n ov

er s

umm

er (

limits

se

lect

ive

with

draw

al a

nd m

ay

be s

ourc

e of

pho

spho

rous

from

se

dim

ent)

• pr

actic

e / e

xper

ienc

e in

impl

emen

ting

emer

genc

y re

spon

se p

lan

• pr

actic

ality

of i

nter

mitt

ently

not

usi

ng

the

rese

rvoi

r

• Sh

ut d

own

supp

ly w

hen

toxi

c bl

oom

occ

urs

• Bl

ue g

reen

alg

ae e

mer

genc

y re

spon

se p

lan

• PA

C o

r G

AC

/ oz

one

dosi

ng a

t fi l

trat

ion

plan

t•

Sele

ctiv

e w

ithdr

awal

from

nea

r bo

ttom

of r

eser

voir

to

avoi

d al

gae

• R

eser

voir

des

trat

ifi ca

tion

• C

oppe

r su

lpha

te d

osin

g of

offl i

ne r

eser

voir

• M

onito

r al

gal s

peci

es a

nd c

once

ntra

tion

fort

nigh

tly in

sum

mer

to

defi n

e gr

owth

rat

es a

nd s

ucce

ssio

n•

Mon

itor

phos

phor

us a

nd n

itrog

en, e

spec

ially

in s

prin

g •

If a

sign

ifi ca

nt r

isk

exis

ts, i

nsta

ll de

stra

tifi c

atio

n eq

uipm

ent

• C

onsi

der

deve

lopi

ng a

res

ervo

ir m

odel

to

bett

er u

nder

stan

d an

d m

anag

e th

e al

gal b

loom

pot

entia

l•

Avo

id e

xces

sive

cop

per

sulp

hate

dos

ing

(low

dos

es, t

arge

ting

hots

pots

on

ly)

• W

here

blo

oms

occu

r m

ore

freq

uent

ly t

han

1 in

10

year

s an

d ca

nnot

be

prev

ente

d du

e to

the

wat

er s

ourc

e, in

stal

l PA

C o

r G

AC

/ oz

one

dosi

ng

at fi

ltrat

ion

plan

t•

Test

inci

dent

and

em

erge

ncy

resp

onse

pla

n (t

wic

e ye

arly

is p

refe

rabl

e)

Oth

er

rela

ted

Fac

t S

he

ets

: •

11. R

esid

ence

Tim

e, S

hort

Cir

cuiti

ng a

nd S

trat

ifi ca

tion

of R

eser

voir

s•

12. C

onta

min

ated

Infl o

ws

to R

eser

voir

s

Use

ful

Lit

era

ture

: •

Chu

ng, S

. and

Gu,

R. T

wo-

dim

ensi

onal

Sim

ulat

ions

of C

onta

min

ant

Cur

rent

s in

a S

trat

ifi ed

Res

ervo

ir. Jo

urna

l of H

ydra

ulic

Eng

inee

ring

, Am

eric

an S

ocie

ty o

f Civ

il En

gine

ers,

Vol.

124,

No.

7, p

p. 7

04-7

11,

1998

.

Use

ful

We

bsi

tes:

• ht

tp://

ww

w.w

orld

bank

.org

/htm

l/fpd

/em

/hyd

ro/m

ts.s

tm•

http

://w

ww

.dhi

.dk/

Con

sulti

ng/R

iver

sLak

es/S

trat

ifi ac

tion.

htm

(

sic)


39

11

. Re

sid

en

ce T

ime

, S

ho

rt C

ircu

itin

g an

d S

trat

ifi c

atio

n i

n R

ese

rvo

irs

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Shor

t r

esid

ence

tim

e d

ue t

o re

serv

oir

draw

dow

n

• Tur

bidi

ty -

from

larg

e ex

pose

d sh

orel

ine

area

s an

d w

ave

actio

n, le

ss s

ettli

ng t

imes

• Tas

te a

nd o

dour

• Cya

noba

cter

ia t

oxin

s -

from

ve

geta

tion

rott

ing

duri

ng

refi l

ling

• Mic

robi

olog

ical

con

tam

inat

ion

-

from

infl o

w• C

olou

r -

less

tim

e to

de

com

pose

in s

unlig

ht

• Loc

atio

n, s

ize

and

vari

abili

ty o

f re

serv

oir

infl o

ws

rela

tive

to o

utle

t• V

aria

bilit

y of

res

ervo

ir le

vel a

nd

exte

nt o

f sha

llow

em

baym

ents

• Ext

ent

of d

ispe

rsiv

e so

ils a

nd

vege

tatio

n re

grow

th• R

ate

of r

efi ll

ing

and

exte

nt o

f dr

awdo

wn

• Mix

ing

of g

ypsu

m in

to d

ispe

rsiv

e so

il ar

eas

to

redu

ce e

rosi

on• B

each

ing

of s

hore

line

area

s w

ith d

ispe

rsiv

e so

ils a

nd lo

ng w

ave

fetc

hes

• Lim

it ex

tent

of d

raw

and

fi ll

• Veg

etat

ion

regr

owth

con

trol

• Abi

lity

to b

ypas

s st

orag

e w

hen

resi

denc

e tim

e is

ver

y lo

w

• Man

age

all r

eser

voir

s to

min

imis

e ex

tent

of

draw

dow

n an

d po

tent

ial f

or w

ave

actio

n• C

ondu

ct s

hore

line

surv

eys

to d

efi n

e di

sper

sive

so

il ar

eas

and

deve

lop

prev

entiv

e m

easu

res

Shor

t ci

rcui

ting

and

leac

hing

- d

ue t

o th

erm

al s

trat

ifi ca

tion

• Rap

id v

aria

tion

in

Mic

robi

olog

ical

and

Tu

rbid

ity p

aram

eter

s -

from

ra

pid

vert

ical

var

iatio

n in

st

ratifi

cat

ion

or s

mal

l sto

rm

even

ts• C

hem

ical

con

tam

inat

ion

- fr

om

sedi

men

ts le

achi

ng m

anga

nese

an

d ir

on (

sum

mer

)• C

yano

bact

eria

tox

ins

• Tas

te a

nd o

dour

com

poun

ds

- fr

om a

lgae

and

nut

rien

ts

leac

hing

and

war

m s

urfa

ce

wat

er

• Qua

lity

of w

ater

ent

erin

g re

serv

oir

• Qua

lity

of a

ltern

ativ

e w

ater

sup

plie

s• L

evel

of t

reat

men

t ab

le t

o be

ach

ieve

d• A

ccur

ate

know

ledg

e of

wat

er q

ualit

y st

ratifi

cat

ion

cycl

e an

d im

pact

s

• Abi

lity

to b

ypas

s st

orag

e• D

esig

n of

inle

t an

d ou

tlet

stru

ctur

es t

o fo

rce

circ

ulat

ion

• Abi

lity

to m

ix/d

estr

atify

the

res

ervo

ir u

sing

ai

r bu

bble

plu

mes

and

/or

mec

hani

cal m

ixer

s• A

bilit

y to

sel

ectiv

ely

with

draw

• Est

ablis

h ro

utin

e m

onito

ring

of d

epth

profi l

e of

res

ervo

ir fo

r w

ater

tem

pera

ture

, dis

solv

ed

oxyg

en a

nd m

anga

nese

• Est

ablis

h a

daily

win

d ru

n m

onito

ring

sta

tion

Oth

er

rela

ted

Fac

t S

he

ets

: •

2. E

nvir

onm

enta

l Haz

ards

with

in C

atch

men

ts•

12. C

onta

min

ated

Infl o

w in

to R

eser

voir

s

Use

ful

Lit

era

ture

: •

Ano

nym

ous,

Sim

ulat

ion

of R

eser

voir

Sur

face

Mix

ing

for

Des

trat

ifi ca

tion

, Wat

er Q

ualit

y N

ews,

14, 2

001.

• Ta

, C.T

. and

Bri

gnal

, W.J.

App

licat

ion

of c

ompu

tatio

nal fl

uid

dyn

amic

s te

chni

que

to s

tora

ge r

eser

voir

stu

dies

. Wat

er S

cien

ce T

echn

olog

y, 37

(2),

219-

226,

199

8.•

Stef

an, H

. and

Gu,

R. C

once

ptua

l des

ign

proc

edur

e fo

r hy

drau

lic d

estr

atifi

catio

n sy

stem

s in

sm

all p

onds

, lak

es o

r re

serv

oirs

for

wat

er q

ualit

y im

prov

emen

t. W

ater

Res

ourc

es B

ulle

tin, J

ourn

al o

f the

A

mer

ican

Wat

er R

esou

rces

Ass

ocia

tion,

27(

6), 9

67-9

78, 1

991.


40

12

. Co

nta

min

ate

d I

nfl

ow

in

to R

ese

rvo

irs

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Con

tam

inat

ed

surf

ace

wat

er

• Tur

bidi

ty -

from

se

dim

ent

• Mic

robi

olog

ical

co

ntam

inat

ion

- fr

om

oil,

petr

ol fr

om r

oads

an

d ot

her

haza

rdou

s m

ater

ial

• Lan

d us

e su

rrou

ndin

g ba

sin

• Fre

quen

cy o

f act

iviti

es in

are

as

surr

ound

ing

basi

ns (

eg m

aint

enan

ce

and

oper

atio

ns)

• Cap

acity

of c

atch

dra

ins

• Wid

th a

nd t

ype

of b

uffe

r zo

ne (

eg. l

ow

gras

s or

nat

ive

bush

land

)

• Cat

ch d

rain

s to

div

ert

cont

amin

atio

n• B

uffe

r zo

nes

arou

nd t

he r

eser

voir

or

bas

in t

o he

lp fi

lter

surf

ace

wat

er a

nd t

o ex

clud

e hu

man

ac

tiviti

es

• Rev

iew

qua

lity

of w

ater

ent

erin

g re

serv

oir,

espe

cial

ly u

nder

co

nditi

ons

whi

ch c

ould

be

asso

ciat

ed w

ith c

onta

min

atio

n (e

g st

orm

s)• E

nsur

e ad

equa

te b

uffe

r zo

nes

exis

t to

pre

vent

con

tam

inat

ion

occu

rrin

g cl

ose

to b

asin

s or

res

ervo

irs

• Buf

fer

zone

s ar

ound

bas

ins

and

rese

rvoi

rs a

lso

help

to fi l

ter

cont

amin

atio

n of

sur

face

wat

er

Con

tam

inat

ed

grou

ndw

ater

• Mic

robi

olog

ical

co

ntam

inat

ion

• Haz

ardo

us C

hem

ical

co

ntam

inat

ion

• Tur

bidi

ty• C

olou

r

• Ing

ress

of g

roun

dwat

er fr

om

expa

nsio

n / c

ontr

actio

n of

con

cret

e lin

ing

duri

ng d

raw

/ fi l

l• M

icro

-con

tam

inat

ion

can

com

e fr

om

soil,

leak

ing

sew

ers,

sept

ic t

ank

effl u

ent

and

effl u

ent

re-u

se• Q

ualit

y of

gro

undw

ater

in a

rea

as it

co

uld

be c

onta

min

ated

by

haza

rdou

s ch

emic

als

(eg

from

indu

stri

al s

pills

, le

aks)

• Reg

ular

insp

ectio

n of

res

ervo

ir o

r ba

sin

• Pro

mpt

rep

air

of le

aks

• Det

erm

ine

likel

y de

pth

and

qual

ity o

f gro

undw

ater

in t

he a

rea

of

the

rese

rvoi

r ba

sin

• Con

duct

reg

ular

insp

ectio

ns o

f res

ervo

ir (

ever

y 2

– 5

year

s de

pend

ing

on t

he a

ge o

f the

bas

in a

nd t

he r

isk

from

its

loca

tion)

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

1 to

9: R

isks

with

in c

atch

men

ts

Use

ful

Lit

era

ture

: •

Gu,

R.,

McC

utch

eon,

S. a

nd W

ang,

P. F.

Mod

ellin

g re

serv

oir

dens

ity u

nderfl o

w a

nd in

terfl

ow

from

a c

hem

ical

spi

ll. W

ater

Res

ourc

es R

esea

rch,

Jour

nal o

f the

Am

eric

an G

eoph

ysic

al U

nion

, 32(

3),

697-

707,

Mar

ch 1

996.


41

13

. Exc

ess

ive

Dra

w o

r F

ill

of

Re

serv

oir

sS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Exce

ssiv

e dr

awdo

wn

(M

inim

um O

pera

ting

Leve

l) -

les

s th

an

15%

of t

otal

vol

ume

resu

lting

in:

• ex

cess

ive

shor

elin

e er

osio

n at

inle

t po

ints

• re

duce

d re

side

nce

times

and

gre

ater

sh

ort

circ

uitin

g

• Tur

bidi

ty -

from

ero

sion

and

st

orm

eve

nts

• Mic

robi

olog

ical

con

tam

inat

ion

- fr

om r

educ

ed d

ie o

ff du

e to

lo

w r

esid

ence

tim

e)• C

olou

r -

from

red

uced

UV

ex

posu

re t

ime

• man

gane

se, d

isso

lved

iron

, an

d su

lphi

des

due

to n

eed

to

use

bot

tom

out

let

• Loc

atio

n of

last

out

let

abov

e bo

ttom

out

let

• Exp

erie

nces

with

veg

etat

ion

regr

owth

the

n refi l

ling

- c

hang

es in

tas

te, o

dour

, bac

teri

al

and

alga

l con

cent

ratio

ns• E

xten

t of

str

atifi

catio

n in

res

ervo

ir a

nd

dete

rior

atio

n of

bot

tom

sta

gnan

t w

ater

• Abi

lity

of s

torm

eve

nts

to g

ener

ate

turb

idity

whi

ch s

ettle

s sl

owly

• Lev

el o

f dis

colo

urat

ion

and

mic

roor

gani

sm

conc

entr

atio

n in

sto

rm r

unof

f• A

cces

s to

sla

sh r

egro

wth

• Res

ervo

ir a

erat

ion

to a

void

man

gane

se /

iron

/ su

lphi

des

in b

otto

m w

ater

• Mul

tiple

sel

ectiv

e w

ithdr

awal

tow

er t

o av

oid

taki

ng b

otto

m w

ater

• Sla

shin

g re

grow

th a

long

sho

relin

es• R

ock

gabi

on d

issi

patio

n st

ruct

ures

at

maj

or infl o

w g

ullie

s to

min

imis

e er

osio

n• S

et m

inim

um o

pera

ting

leve

ls s

o th

at

bott

om w

ater

is n

ot w

ithdr

awn

• Rec

ord

and

docu

men

t pr

evio

us im

pact

s of

dr

awdo

wn

leve

ls o

n w

ater

qua

lity

• Con

side

r re

serv

oir

aera

tion

whe

re b

otto

m

wat

er m

ay o

ccas

iona

lly n

eed

to b

e dr

awn

duri

ng

times

of l

ow w

ater

leve

ls• E

stab

lish

soil

type

s on

sur

face

s of

sho

relin

e do

wn

to m

inim

um o

pera

ting

leve

l (M

OL)

and

tr

eat

easi

ly e

rode

d or

dis

pers

ive

area

s• E

stab

lish

vege

tatio

n bu

ffer

zone

s do

wn

to fu

ll su

pply

leve

l (FS

P) (

100

m t

o 30

0 m

wid

e)• P

lace

ene

rgy

diss

ipat

ion

stru

ctur

es t

o m

inim

ise

eros

ion

Exce

ssiv

e refi l

l -

resu

lting

in:

• ra

pid

inun

datio

n of

ve

geta

tion

• ra

pid

wet

ting

of la

rge

area

s of

pre

viou

sly

dry

soil

• Mic

robi

olog

ical

con

tam

inat

ion

-Cya

noba

cter

ia t

oxin

s, fu

ngi

and

bact

eria

• T

aste

and

odo

ur c

ompo

unds

• Tur

bidi

ty• C

hem

ical

con

tam

inat

ion

- fr

om o

rgan

ics,

diss

olve

d m

anga

nese

and

iron

• Col

our

• Gro

ss p

artic

ulat

e

• Sho

relin

e m

ater

ial (

eg. d

ispe

rsiv

e cl

ay,

coar

se s

and,

or

impe

rmea

ble

rock

) an

d as

sess

men

t of

soi

l pro

pert

ies

afte

r pr

olon

ged

dry

cond

ition

s fo

llow

ed b

y ra

pid

wet

ting

• Sho

relin

e m

ater

ial a

t di

ffere

nt w

ater

leve

ls

with

in t

he r

eser

voir

esp

ecia

lly n

ear

outle

ts• S

lope

of t

he s

hore

line

whi

ch w

ill a

ffect

the

w

ave

actio

n• P

redo

min

ant

win

d di

rect

ions

and

typ

e of

w

ave

actio

n at

sho

relin

e• P

erio

d of

dra

wdo

wn.

Dur

ing

a lo

ng p

erio

d of

dra

wdo

wn,

sub

stan

tial v

eget

atio

n m

ass

can

esta

blis

h. T

hen,

dur

ing

rapi

d refi l

ling,

orga

nics

, bac

teri

a, fu

ngi,

alga

e an

d di

scol

oura

tion

can

occu

r

• Str

engt

hene

d sh

ore

linin

g eg

. with

co

ncre

te, g

rave

l, ro

ck p

avin

g es

peci

ally

ne

ar o

utle

t an

d in

let

stru

ctur

es• G

ypsu

m m

ixin

g an

d co

mpa

ctin

g in

to t

op

150

mm

dep

th o

f dis

pers

ive

soils

are

as• M

axim

um r

efi ll

rat

es fo

r of

fstr

eam

st

orag

es• I

nitia

l rem

oval

of a

ll la

rge

tree

s fr

om

draw

and

fi ll

zone

• Per

iodi

c sl

ashi

ng o

f reg

row

th w

hile

re

serv

oir

is in

dra

wdo

wn

cond

ition

• Ide

ntify

any

occ

urre

nce

of h

igh

refi l

l rat

e an

d ho

w it

affe

cted

wat

er q

ualit

y • T

reat

or

plac

e lin

ing

(eg.

rock

bea

chin

g) o

ver

disp

ersi

ve s

oil z

ones

esp

ecia

lly n

ear

outle

t st

ruct

ures

and

inle

t zo

nes

• Con

side

r sl

ashi

ng r

egro

wth

ove

r su

mm

er

/ aut

umn

peri

od a

long

exp

osed

, nor

mal

ly

inun

date

d ar

eas

• Con

stru

ct r

ock

pavi

ng a

nd g

royn

es t

o m

inim

ise

wav

e ac

tion

at s

teep

sho

relin

es a

nd p

oint

s• E

stab

lish

max

imum

refi

llin

g ra

tes

for

offs

trea

m

stor

ages

whi

ch li

mit

deca

y ef

fect

s of

inun

date

d ve

geta

tion

• Con

side

r is

olat

ing

any

larg

e, fl

at e

mba

ymen

ts

that

hav

e di

sper

sive

soi

ls, b

ecau

se w

ave

actio

n w

ill s

tir u

p la

rge

area

s of

rec

ently

inun

date

d su

rfac

eU

nusu

ally

rap

id r

ate

of

draw

dow

n

• Tur

bidi

ty -

from

land

slip

s an

d hi

gh r

ates

of e

rosi

on a

t m

ajor

in

let

poin

ts• N

atur

al o

rgan

ic m

atte

r• G

ross

par

ticul

ates

- fr

om

rapi

d di

e of

f of w

ater

ree

ds

and

atta

ched

alg

ae b

eds

• Tas

te a

nd o

dour

com

poun

ds• M

icro

biol

ogic

al c

onta

min

atio

n -fr

om d

ead

anim

als

(incl

fi sh

) ca

ught

in m

ud, f

ungi

• Wat

er s

urfa

ce a

rea

to d

epth

cur

ve E

xten

t of

sho

relin

e re

eds

and

atta

ched

alg

ae b

eds

• Lik

elih

ood

of a

maj

or s

torm

eve

nt w

hen

at

the

end

of a

rap

id d

raw

dow

n pe

riod

• Pre

viou

s ex

peri

ence

with

land

slip

s• P

rese

nce

of la

rge

area

s of

dis

pers

ive

soils

• Ext

ent

of r

ock

beac

hing

and

pav

ing,

espe

cial

ly n

ear

inle

ts a

nd o

utle

ts• P

rese

nce

of s

hallo

w e

mba

ymen

t so

ils w

hich

, w

hen

satu

rate

d, c

an b

e tr

aps

for

anim

als

• Str

engt

hene

d sh

ore

linin

g (e

g ro

ck p

avin

g, gr

avel

bea

chin

g) e

spec

ially

nea

r m

ajor

in

lets

and

out

lets

• Avo

id r

apid

cha

nge

whe

re la

rge

dept

h ch

ange

res

ults

in s

mal

l sur

face

are

a ch

ange

, ie.

ste

ep s

lope

s• R

educ

e ra

te o

f dra

wdo

wn

to a

llow

eq

uilib

rium

of p

ore

pres

sure

in

pote

ntia

lly u

nsta

ble

soils

• Ste

p dr

awdo

wn

to li

mit

exte

nt o

f die

off

of w

ater

wee

ds /

alga

e• R

egul

ar in

spec

tion

and

rem

oval

of d

ead

anim

als, fi s

h an

d de

ad w

ater

ree

ds

• Ide

ntify

any

occ

urre

nces

of r

apid

dra

w d

own

havi

ng a

ffect

ed w

ater

qua

lity

• Est

ablis

h m

axim

um d

raw

dow

n lim

its, s

eque

nces

of

ste

p do

wns

or

hold

poi

nts

• Ide

ntify

vul

nera

ble

soil

zone

s an

d be

ach

or

isol

ate

with

cut

-off

wal

ls• B

each

ing

near

out

let

stru

ctur

es• I

nlet

pip

es, c

oncr

ete

lined

chu

tes

or b

each

ing

whe

re m

ajor

infl o

w o

ccur

s do

wn

to m

inim

um

oper

atin

g le

vel

• Har

vest

sho

relin

e w

ater

ree

d be

ds in

res

ervo

irs

whe

re d

raw

dow

n is

occ

asio

nally

gre

ater

th

an 3

m


42

Oth

er

rela

ted

Fac

t S

he

ets

: •

7. L

and

Use

With

in C

atch

men

ts•

11. R

esid

ence

Tim

e, S

hort

Cir

cuiti

ng a

nd S

trat

ifi ca

tion

of R

eser

voir

s

Use

ful

Lit

era

ture

: •

Nie

nhüs

er A

.E. a

nd B

rach

es P

. Pro

blem

s an

d pr

actic

al e

xper

ienc

es d

urin

g refi l

ling

of t

he K

ersp

e R

eser

voir

und

er u

nfav

oura

ble

clim

atic

con

ditio

ns. I

n: D

olej

s P.,

et

al, R

eser

voir

Man

agem

ent

and

Wat

er S

uppl

y - A

n In

tegr

ated

Sys

tem

, Sel

ecte

d Pr

ocee

ding

s of

the

Fir

st IA

WQ

-IWSA

Join

t Sp

ecia

list

Con

fere

nce

on R

eser

voir

Man

agem

ent

and

Wat

er S

uppl

y Ð

An

Inte

grat

ed S

yste

m. P

ragu

e, C

zech

R

epub

lic, 1

9-23

May

199

7, 1

998.


43

14

. WT

P R

eli

abil

ity

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

as

sess

ing

lik

eli

ho

od

an

d

seve

rity

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Failu

re o

f dos

ing

equi

pmen

t:-

coa

gula

nt / fl o

c ai

d / p

H

corr

ectio

n / fi

lter

aid

/ PA

C

Failu

re o

f mon

itori

ng e

quip

men

t:

- p

H, t

urbi

dity

, dis

infe

ctan

t

re

sidu

al a

naly

sers

Oth

er:

• U

ncon

trol

led fl o

w in

crea

se•

The

rmal

inst

abili

ty in

cla

rifi e

r -

ca

usin

g hi

gh t

urbi

dity

•

Filte

r tu

rbid

ity b

reak

thro

ugh

on

chan

ge in

pla

nt fl

ow r

ate

- fr

om

fi lte

r be

d m

ud b

allin

g, in

corr

ect

back

was

hing

, or

exce

ssiv

e he

ad

loss

• D

isso

lved

air

fl ot

atio

n re

cycl

e fa

ilure

(ai

r di

sper

sion

sys

tem

)

• M

icro

biol

ogic

al

cont

amin

atio

n•

Che

mic

al

cont

amin

atio

n

-al

umin

ium

, iro

n,

man

gane

se

Turb

idity

• C

olou

r•

Tast

e a

nd o

dour

co

mpo

unds

• C

orro

sive

wat

er

• Pr

esen

ce o

f aut

o st

andb

y /

back

up d

osin

g an

d po

wer

• Li

kelih

ood

of p

ower

failu

res

• St

atus

of g

ener

al e

quip

men

t m

aint

enan

ce

• Li

kelih

ood

of t

elem

etry

fa

ilure

• Li

kelih

ood

of c

ontr

ol fa

ilure

(e

g. pr

ogra

mm

able

logi

c co

ntro

ller

PLC

failu

re)

• A

bilit

y to

kee

p pl

ant

oper

atin

g co

ntin

uous

ly w

ith

only

slo

w fl

ow r

ate

chan

ges

• A

larm

s

• A

utom

atic

fl ow

pac

ing

• M

inim

um fl

ow c

rite

ria

for

clar

ifi er

s•

Floc

pH

mon

itori

ng•

Alu

m fl

ow r

ate

mon

itori

ng•

Filte

r tu

rbid

ity m

onito

ring

• Lo

w fl

ow a

larm

at

dose

poi

nt•

Vis

ual m

onito

ring

/insp

ectio

n (e

g. Po

or fl

oc, n

o do

se fl

ow)

• Fi

lter

L/D

(m

edia

dep

th, e

ffect

ive

size

) >

120

0•

Con

tinuo

us fi

lter

head

loss

• Sh

ort

dela

y tim

e an

d ad

equa

te m

ixin

g be

twee

n pH

adj

ustm

ent

poin

t an

d pH

mon

itori

ng p

oint

• un

inte

rrup

ted

pow

er s

uppl

y•

Equi

pmen

t ba

ckup

incl

udin

g m

onito

ring

equ

ipm

ent

• M

inim

ise

plan

t in

terr

uptio

ns•

Plan

t sh

utdo

wn

• A

ltern

ativ

e w

ater

sou

rce

• A

larm

sys

tem

• C

ondu

ct H

AZ

OP

/ HA

ZA

N

(haz

ard

oppo

rtun

ity a

nd a

naly

sis)

to

confi r

m r

elia

bilit

y•

Inst

all i

f not

pre

sent

:•

back

up p

umps

• un

inte

rrup

ted

pow

er s

uppl

y•

Alu

m fl

owm

eter

• Lo

w le

vel a

larm

s•

Dup

licat

e do

sing

line

s•

Vis

ual i

nspe

ctio

n fa

cilit

y to

co

nfi r

m d

osin

g•

Ensu

re a

dequ

ate

prot

ocol

s /

proc

edur

es e

xist

for:

• m

aint

enan

ce•

trai

ning

• de

liver

y ar

rang

emen

ts•

oper

atio

nal c

heck

s of

m

onito

ring

equ

ipm

ent

Che

mic

als

and

Mat

eria

ls:

• us

e of

con

tam

inat

ed c

hem

ical

s•

runn

ing

out

of c

hem

ical

s•

use

of m

ater

ials

, che

mic

als,

or

clea

ning

age

nts

whi

ch le

ach

at

the

WT

P st

ruct

ures

• re

ceiv

ing

inco

rrec

t tr

eatm

ent

chem

ical

or

unlo

adin

g to

in

corr

ect

loca

tion/

sto

rage

• A

ll ha

zard

s ar

e po

ssib

le•

Exte

nt o

f una

tten

ded

plan

t op

erat

ion

• Si

ze o

f che

mic

al s

tora

ges

• N

atur

e of

che

mic

als

(abi

lity

to r

emov

e w

ith t

reat

men

t)•

Oth

er a

ccom

pany

ing

haza

rds

(eg.

tast

e an

d od

our)

•

Abi

lity

to s

top

the

plan

t or

us

e al

tern

ativ

e su

pply

• C

usto

mer

sen

sitiv

ity /

outr

age

• N

umbe

r of

cus

tom

ers

affe

cted

• Po

ssib

ility

of d

ilutio

n or

bl

endi

ng d

owns

trea

m•

Lega

l res

pons

ibili

ty a

nd

liabi

lity

• Fl

oc /

pH m

onito

ring

• A

lum

fl ow

rat

e m

onito

ring

• Fi

lter

turb

idity

mon

itori

ng•

Che

mic

al s

tora

ge t

ank

low

leve

l ala

rm•

Vis

ual m

onito

ring

/insp

ectio

n (e

g. Po

or fl

oc, n

o do

se fl

ow)

• Pl

ant

shut

dow

n•

Alte

rnat

ive

wat

er s

ourc

e•

Che

mic

als

acqu

isiti

on p

ract

ices

req

uiri

ng r

ando

m a

naly

sis

for

trac

e co

ntam

inan

ts (

eg. m

anga

nese

leve

l in

ferr

ic c

hlor

ide

coag

ulan

t)•

Proh

ibit

chem

ical

s an

d m

ater

ials

whi

ch a

re k

now

n to

res

ult

in t

aste

and

odo

ur p

robl

ems

whe

n in

con

tact

with

wat

er (

eg.

xyle

ne s

olve

nts)

• U

se o

nly

copp

er s

ulph

ate

for

alga

e co

ntro

l whe

n pl

ant

is o

ffl in

e an

d m

onito

r fo

r re

sidu

als

• Si

gnag

e to

dir

ect

safe

che

mic

al u

nloa

ding

• D

iffer

ent

cam

lock

fi tt

ings

for

each

che

mic

al s

tora

ge

• D

evel

op in

cide

nt a

nd e

mer

genc

y re

spon

se p

roce

dure

s•

Kee

p re

cord

s of

inci

dent

s•

Ensu

re a

dequ

ate

prot

ocol

s /

oper

atio

nal p

roce

dure

s ex

ist

for:

- sw

itchi

ng t

o al

tern

ativ

e su

pply

- qu

ality

con

trol

of c

hem

ical

s •

Ensu

re a

ll m

ater

ials

in c

onta

ct w

ith

wat

er a

re s

uita

ble

and

appr

oved

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

.•

Fact

She

ets

rela

ting

to W

TP

Cap

abili

ty: 1

5 –

22.

• 23

. Dis

infe

ctio

n Sy

stem

– R

elia

bilit

y•

24. D

isin

fect

ion

Syst

em -

Des

ign

Cap

abili

ty


44

Use

ful

Lit

era

ture

:•

Ren

ner

R.C

., H

egg

B.A

. Sel

f-Ass

essm

ent

Gui

de fo

r Su

rfac

e W

ater

Tre

atm

ent

Plan

t O

ptim

izat

ion.

AW

WA

RF/

AW

WA

, 199

7.•

Wat

er T

reat

men

t Pl

ant

Des

ign,

AW

WA

, 3rd

Edi

tion,

McG

raw

-Hill

Pro

fess

iona

l Pub

lishi

ng, 1

997.

•

Rob

erts

A. B

., D

eLai

ne J.

A., W

ater

Tre

atm

ent

Plan

ts fo

r Sm

all C

omm

uniti

es, R

epor

t 98

, Urb

an W

ater

Res

earc

h A

ssoc

iatio

n of

Aus

tral

ia, 1

995.

• C

MPS

&F

Envi

ronm

enta

l. A

ltern

ativ

e O

vers

eas W

ater

Tre

atm

ent

and

Supp

ly P

ract

ices

, Rep

ort

112,

Urb

an W

ater

Res

earc

h A

ssoc

iatio

n of

Aus

tral

ia, 1

996.

Use

ful

We

bsi

tes:

• ht

tp://

ww

w.a

wa.

asn.

au/e

duca

tion/

• ht

tp://

ww

w.w

ater

qual

ity.c

rc.o

rg.a

u/


45

15

. WT

P D

esi

gn C

apab

ilit

y -

To

xin

sS

ou

rce

of

Haz

ard

/Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Toxi

ns in

raw

wat

er:

• Ex

ceed

ance

of

desi

gn u

pper

lim

it

• Ex

ceed

ance

of

desi

gn r

ate

of

chan

ge

• N

ot d

etec

ted

by m

onito

ring

sy

stem

s

• N

orm

al t

reat

ed

wat

er t

arge

t w

rong

ly s

pecifi e

d

• C

yano

bact

eria

l tox

ins

• D

isin

fect

ion

by-

prod

ucts

(eg

. TH

Ms,

chlo

roac

etic

aci

ds)

• Ta

ste

and

odou

r co

mpo

unds

• T

ime

at w

hich

pro

blem

occ

urs

and

the

dura

tion

of u

natt

ende

d op

erat

ion

• R

ate

of c

hang

e of

tox

in c

once

ntra

tion

• D

urat

ion

and

mag

nitu

de o

f tox

in e

vent

s

• A

bilit

y to

det

ect

toxi

ns

• N

atur

e of

tox

ins

and

abili

ty t

o re

mov

e th

em

with

tre

atm

ent

• O

ther

acc

ompa

nyin

g ha

zard

s, eg

. tur

bidi

ty,

mic

robi

olog

ical

con

tam

inat

ion

• A

bilit

y to

sto

p th

e pl

ant

or u

se a

ltern

ativ

e su

pply

• Su

pern

atan

t an

d w

ashw

ater

rec

ycle

opt

ions

• C

usto

mer

sen

sitiv

ity /

outr

age

• N

umbe

r of

cus

tom

ers

affe

cted

• Ty

pes

of la

rge

cust

omer

s (e

g so

ft d

rink

m

anuf

actu

rers

)

• Po

ssib

ility

of d

ilutio

n or

ble

ndin

g do

wns

trea

m

• Le

gal r

espo

nsib

ility

and

liab

ility

• Se

e Fa

ct S

heet

s 1-

13 r

egar

ding

cat

chm

ents

and

re

serv

oirs

to

dete

rmin

e up

stre

am r

isks

• Pr

e-ch

lori

natio

n

• A

dditi

on o

f PA

C/G

AC

• O

zona

tion

• Po

st c

hlor

inat

ion

• A

dditi

onal

coa

gula

nt

• R

educ

e or

sto

p su

pern

atan

t (s

ludg

e la

goon

) re

cycl

e

• Pl

ant

slow

dow

n / s

hutd

own

• Sw

itch

to a

ltern

ativ

e su

pply

• D

isso

lved

air

fl ot

atio

n to

re

mov

e al

gae

cells

• R

un fi

ltere

d w

ater

thr

ough

G

AC

bed

• R

educ

e or

sto

p w

ashw

ater

re

cycl

e

• C

usto

mer

and

hea

lth

depa

rtm

ent

notifi

cat

ions

• Es

tabl

ish

risk

bas

ed c

rite

ria

for

the

leve

l of t

reat

men

t an

d to

xin

rem

oval

effe

ctiv

enes

s, an

d de

term

ine

effe

ctiv

enes

s of

tr

eatm

ent

agai

nst

the

crite

ria

• Ed

ucat

e cu

stom

ers

abou

t to

xin

risk

s (e

g. if

toxi

n le

vel i

s be

low

tar

get,

then

wat

er is

oka

y)

• M

onito

r al

gae

spec

ies

in r

iver

/ re

serv

oir

upst

ream

of t

he

plan

t

• Im

prov

e se

nsiti

vity

, spe

ed a

nd a

ccur

acy

of t

oxin

m

easu

rem

ent

• En

sure

ade

quat

e in

cide

nt a

nd e

mer

genc

y re

spon

se p

lans

/ op

erat

iona

l pro

cedu

res

exis

t fo

r:

• sw

itchi

ng t

o al

tern

ativ

e su

pply

• sh

ort

term

shu

tdow

n

• au

tom

atic

pla

nt s

hutd

own

• re

duce

d pl

ant fl o

w

• in

cide

nt m

anag

emen

t

• ob

tain

ing

timel

y an

d re

liabl

e to

xin

anal

yses

• R

evie

w r

ecyc

ling

prac

tices

• Es

tabl

ish

suita

ble

criti

cal l

imits

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

• 14

. WT

P R

elia

bilit

y•

23. D

isin

fect

ion

Syst

em –

Rel

iabi

lity

• 24

. Dis

infe

ctio

n Sy

stem

- D

esig

n C

apab

ility


46

16

. WT

P D

esi

gn C

apab

ilit

y -

Alk

alin

ity

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Alk

alin

ity in

raw

w

ater

:•

Exce

edan

ce o

f de

sign

upp

er li

mit

• Ex

ceed

ance

of

desi

gn r

ate

of

chan

ge•

Nor

mal

tre

ated

w

ater

tar

get

wro

ngly

spe

cifi e

d

• C

orro

sion

•

pH o

ut o

f ran

ge•

Mic

robi

olog

ical

co

ntam

inat

ion

- fr

om

- lo

ss o

f coa

gula

tion

lead

ing

to p

roto

zoa

and

viru

ses

not

bein

g re

mov

ed

- in

effe

ctiv

e di

sinf

ectio

n du

e to

pH

to

o hi

gh o

r to

o lo

w• T

aste

and

odo

ur

com

poun

ds -

from

di

sinf

ectio

n re

sidu

als

• A

bilit

y to

acc

urat

ely

mea

sure

pH

• D

urat

ion

and

mag

nitu

de o

f alk

alin

ity

• Ex

tent

of c

oppe

r, ir

on o

r le

ad c

orro

sion

• H

isto

ry a

nd fr

eque

ncy

of p

oor

perf

orm

ance

aga

inst

tar

gets

(eg

. co

rros

ivity

, pH

, alk

alin

ity)

• T

ime

at w

hich

pro

blem

occ

urs

(aft

erno

on

peak

or

nigh

t? Is

ope

rato

r pr

esen

t?)

• R

espo

nd t

hrou

gh a

utom

atio

n•

Leve

l of t

rain

ing

of o

pera

tors

• Tr

eate

d w

ater

tar

get

• Bu

fferi

ng c

apac

ity o

f raw

wat

er•

Oth

er a

ccom

pany

ing

risk

s (e

g. m

icro

bial

br

eakt

hrou

gh a

t fi l

ters

) •

Poss

ibili

ty o

f the

nor

mal

tar

get

bein

g se

t in

corr

ectly

• Ex

tent

and

mag

nitu

de o

f leg

al

resp

onsi

bilit

y an

d lia

bilit

y•

Indu

stry

con

cern

s ab

out

hard

ness

(du

e to

lim

e do

sing

) an

d T

DS

incr

ease

/ va

riat

ion

(eg.

calc

ium

/ lim

e, s

odiu

m /

caus

tic s

oda)

• Se

e fa

ct s

heet

s re

gard

ing

rese

rvoi

rs

and

catc

hmen

ts t

o de

term

ine

upst

ream

al

kalin

ity r

isks

• C

ontin

uous

mon

itori

ng o

f tu

rbid

ity, c

olou

r, an

d pH

with

hig

h an

d lo

w le

vel a

larm

s•

Dec

reas

e fl o

wra

te•

Lim

e / C

O2

stab

ilisa

tion

• A

utom

atic

pH

tri

m a

nd fl

ow

paci

ng t

o co

ntro

l rea

gent

dos

e•

Shut

off

plan

t on

hig

h fi l

ter

turb

idity

or

high

/ lo

w p

H a

larm

• En

sure

the

follo

win

g ha

ve b

een

cons

ider

ed a

nd a

sses

sed:

• co

agul

atio

n, p

H c

ontr

ol a

nd s

tabi

lisat

ion

reag

ent

dosi

ng

relia

bilit

y•

cont

inuo

us p

H m

onito

ring

in r

aw a

nd t

reat

ed w

ater

• re

mot

e co

ntro

l•

upst

ream

con

trol

s (e

g se

lect

ive

with

draw

al, a

ltern

ate

sour

ces,

prev

ent

shor

t ci

rcui

ting,

prev

ent

alga

e)•

Enco

urag

e re

sear

ch a

nd d

evel

opm

ent

of t

reat

men

t pr

oces

s fo

r al

kalin

ity c

ontr

ol•

Esta

blis

h su

itabl

e cr

itica

l lim

its fo

r pH

and

sta

bilis

atio

n co

ntro

l ch

emic

als

• En

sure

app

ropr

iate

pro

toco

ls a

nd o

pera

tiona

l pro

cedu

res

are

in p

lace

for:

• in

cide

nt a

nd e

mer

genc

y m

anag

emen

t•

reco

rdin

g of

inci

dent

s•

usin

g al

tern

ativ

e su

pplie

s•

auto

mat

ic p

lant

ope

ratio

n / s

hutd

own

• re

duce

d pl

ant fl o

w•

oper

atio

n to

cor

rect

alk

alin

ity a

nd p

H t

arge

ts

* Cy

anob

acte

ria (b

lue

gree

n al

gae)

can

raise

pH

dra

mat

ically

in s

oft w

ater

, eg.

from

pH

7 to

pH

10.

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

.•

14. W

TP

Rel

iabi

lity

• 22

. WT

P D

esig

n C

apab

ility

- T

urbi

dity


47

17

. WT

P D

esi

gn C

apab

ilit

y -

Co

lou

rS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Col

our

in r

aw w

ater

:•

Exce

edan

ce o

f de

sign

upp

er li

mit

• Ex

ceed

ance

of

desi

gn r

ate

of

chan

ge•

Nor

mal

tre

ated

w

ater

tar

get

wro

ngly

spe

cifi e

d•

Sele

ctiv

e w

ithdr

awal

from

be

low

res

ervo

ir

ther

moc

line

(Mn,

Fe

rich

zon

e)

• N

atur

al o

rgan

ic

mat

ter

• C

hem

ical

co

ntam

inat

ion

-al

umin

ium

, iro

n,

man

gane

se•

Dis

infe

ctio

n by

-pr

oduc

ts•

Mic

robi

olog

ical

co

ntam

inat

ion

- fr

om b

acte

ria

regr

owth

• Tu

rbid

ity

• Pr

esen

ce a

nd r

elia

bilit

y of

onl

ine

cont

inuo

us

colo

ur m

onito

r on

raw

wat

er•

Rat

e of

cha

nge

• Ty

pe/p

ropo

rtio

n le

ft a

fter

tre

atm

ent

• D

urat

ion

and

mag

nitu

de o

f pea

k•

Targ

et a

nd s

tabi

lity

of fl

occu

latio

n pH

• N

atur

e of

col

our

- e

ase

of fl

occu

latio

n•

Iron

/man

gane

se le

ft a

fter

tre

atm

ent

(col

our

prod

uced

aft

er c

hlor

ine

addi

tion)

• O

ther

acc

ompa

nyin

g ha

zard

s (e

g. pa

thog

ens)

•

Alk

alin

ity o

f raw

wat

er•

Inte

nsity

of r

apid

mix

ing

stag

e an

d or

der

of c

oagu

latio

n an

d pH

con

trol

che

mic

al

addi

tion

• H

ydra

ulic

mix

ing

inte

nsity

und

er a

vera

ge t

o lo

w fl

ow r

ates

• M

inim

um w

ater

tem

pera

ture

dur

ing

fl occ

ulat

ion

• Se

e Fa

ct S

heet

s 1

- 13

reg

ardi

ng c

atch

men

ts

and

rese

rvoi

rs t

o de

term

ine

upst

ream

co

lour

ris

ks

• M

onito

r tu

rbid

ity

(ala

rm)

• D

ecre

ase fl o

wra

te•

Adj

ust

reag

ents

• In

crea

se n

umbe

r of

on

line

clar

ifi er

s / fi

lter

s•

Red

uce

supe

rnat

ant

(slu

dge

lago

on)

recy

cle

• Sh

ut o

ff pl

ant

• C

hlor

amin

atio

n

• En

sure

the

follo

win

g ha

ve b

een

cons

ider

ed a

nd a

sses

sed:

• co

ntin

uous

mon

itori

ng•

upst

ream

pre

vent

ive

mea

sure

s (e

g se

lect

ive

with

draw

al, s

elec

t so

urce

s, pr

even

t sh

ort

circ

uitin

g, ae

ratio

n)•

coag

ulan

t / c

oagu

latio

n•

oper

ator

tra

inin

g / j

ar t

ests

• fl o

c pH

con

trol

• m

echa

nica

l fl a

sh m

ixin

g (G

> 7

50 s

-1)

• fi l

ter

aid

poly

mer

, set

tling

aid

pol

ymer

• U

pgra

de W

TP:

• ad

d di

ssol

ved

air fl o

tatio

n•

incr

ease

fl oc

cula

tion

time

• in

crea

se fi

lters

• En

sure

app

ropr

iate

pro

toco

ls a

nd o

pera

tiona

l pro

cedu

res

exis

t fo

r:•

use

of a

ltern

ativ

e su

pplie

s•

auto

mat

ic p

lant

shu

tdow

n•

redu

ced

plan

t fl o

w•

rem

ote

plan

t op

erat

ion

• ja

r te

sts

to s

et c

oagu

lant

dos

e an

d fl o

ccul

atio

n tim

e•

Esta

blis

h su

itabl

e cr

itica

l lim

its

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

• 14

. WT

P R

elia

bilit

y•

23. D

isin

fect

ion

Syst

em –

Rel

iabi

lity

• 24

. Dis

infe

ctio

n Sy

stem

- D

esig

n C

apab

ility


48

18

. WT

P D

esi

gn C

apab

ilit

y -

Iro

n &

Man

gan

ese

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Iron

or

man

gane

se

(Fe,

Mn)

in r

aw

wat

er:

• Ex

ceed

ance

of

desi

gn u

pper

lim

it•

Une

xpec

ted

incr

ease

not

de

tect

ed•

Nor

mal

tre

ated

w

ater

tar

get

wro

ngly

spe

cifi e

d

• Ir

on, m

anga

nese

-

resu

lting

in b

lack

w

ater

, col

our

afte

r ch

lori

natio

n, s

tain

ed

laun

dry,

off t

aste

s•

Incr

ease

in

chlo

ram

ine

or

chlo

rine

dec

ay r

ate

- lo

w r

esid

uals

at

out

er a

reas

of

dist

ribu

tion

syst

em•

Turb

idity

- fr

om

build

up

of s

limes

/ b

iofi l

ms

in p

ipes

tr

igge

ring

hig

h tu

rbid

ity e

vent

s in

hi

gh fl

ows

• A

bilit

y to

det

ect

cont

inuo

usly

• R

ate

of c

hang

e in

Mn/

Fe c

once

ntra

tion

• D

urat

ion

of h

igh

Mn/

Fe c

once

ntra

tion

• M

agni

tude

of c

once

ntra

tion

• A

bilit

y to

rem

ove

by t

reat

men

t, eg

. oxi

dant

s an

d pH

con

trol

the

n fi l

trat

ion

or D

AF

• A

bilit

y to

sto

p pl

ant

• A

vaila

bilit

y of

alte

rnat

ive

supp

ly•

His

tory

and

freq

uenc

y of

rel

evan

t co

mpl

aint

s (e

g. st

aine

d la

undr

y, hi

gh c

olou

r, ta

ste

and

odou

r)•

Exte

nt o

f dow

nstr

eam

effe

cts

and

issu

es (

eg.

post

chl

orin

atio

n ca

usin

g co

lour

pro

blem

s)•

Leng

th o

f pip

es in

dis

trib

utio

n sy

stem

and

ex

tent

of b

iofi l

m g

row

th•

Abi

lity

to r

e-di

sinf

ect

in o

uter

dis

trib

utio

n ar

eas

• C

usto

mer

out

rage

, num

ber

of c

usto

mer

s af

fect

ed•

Sens

itivi

ty o

f cus

tom

ers,

eg. h

ospi

tals

, be

vera

ge m

anuf

actu

rers

• Le

gal r

espo

nsib

ility

and

liab

ility

• Se

e Fa

ct S

heet

s 1

- 13

reg

ardi

ng c

atch

men

ts

and

rese

rvoi

rs t

o de

term

ine

upst

ream

Fe

and

Mn

risk

s

• O

xida

tion

by p

erm

anga

nate

an

d pr

e-lim

e, t

hen

alum

or

iron

coa

gula

tion,

the

n fi l

ter

• A

ltern

ativ

e su

pply

• C

hlor

amin

atio

n•

Dec

reas

e pl

ant fl o

w r

ate

• Pl

ant

shut

dow

n•

Aer

atio

n of

ser

vice

res

ervo

ir•

Rai

se s

elec

tive

with

draw

al

outle

t at

sup

ply

dam

• pH

con

trol

at

oxid

ant

dose

po

int

• M

n/Fe

mon

itori

ng a

nd a

larm

at

pla

nt in

let

• En

sure

the

follo

win

g ha

ve b

een

cons

ider

ed a

nd a

sses

sed:

• ra

w w

ater

/ fi l

tere

d w

ater

mon

itori

ng fo

r Fe

/Mn

(eg.

cont

inuo

us

with

hig

h le

vel a

larm

)•

rem

ote

cont

rol o

f oxi

dant

and

pre

lim

e do

se a

nd d

ose

poin

ts•

upst

ream

pre

vent

ive

mea

sure

s (e

g se

lect

ive

near

-sur

face

w

ithdr

awal

, sel

ect

sour

ces)

• tr

eatm

ent

relia

bilit

y (e

g. du

ty /

stan

dby

dosi

ng)

• co

nditi

onin

g of

fi lte

rs (

eg. p

ost

lime

plus

chl

orin

e be

fore

fi lte

rs)

• M

onito

r cu

stom

er c

ompl

aint

s an

d as

sess

com

plai

nt t

ypes

to

iden

tify

Fe/M

n pr

oble

ms

eg:

• sw

imm

ing

pool

s tu

rnin

g ye

llow

aft

er a

dditi

on o

f chl

orin

e•

stai

ned

laun

dry

• bl

ack

wat

er•

Rev

iew

des

ign

cont

inge

ncie

s (e

g. te

mpo

rary

or

perm

anen

t do

sing

fa

cilit

ies

at W

TP)

• Es

tabl

ish

suita

ble

targ

ets

and

criti

cal l

imits

• En

cour

age

rese

arch

and

dev

elop

men

t of

tre

atm

ent

proc

ess,

Fe a

nd

Mn

redu

ctio

n, c

ontr

ol a

nd im

pact

s on

pip

e ne

twor

k•

Ensu

re a

ppro

pria

te p

roto

cols

and

ope

ratio

nal p

roce

dure

s ex

ist

for:

• us

ing

alte

rnat

ive

supp

lies

• au

tom

atic

pla

nt s

hutd

own

• re

duce

d pl

ant fl o

w•

rem

ote

plan

t op

erat

ion

• st

art

up o

f req

uire

d ad

ditio

nal o

xida

tion

proc

esse

s•

inci

dent

man

agem

ent

• re

cord

ing

of in

cide

nts

• no

tifi c

atio

n of

pot

entia

lly a

ffect

ed s

ensi

tive

cust

omer

s

Oth

er

rela

ted

Fac

t S

he

ets

: •

14. W

TP

Rel

iabi

lity

• Fa

ct S

heet

s re

latin

g to

WT

P D

esig

n C

apab

ility

: 15

- 22

• Fa

ct S

heet

s re

latin

g to

Cat

chm

ents

and

Res

ervo

irs:

1 –

13

Use

ful

We

bsi

tes:

• ht

tp://

ww

w.ia

nr.u

nl.e

du/p

ubs/

wat

er/g

1280

.htm


49

19

. WT

P D

esi

gn C

apab

ilit

y -

Ind

ust

rial

Ch

em

ical

sS

ou

rce

of

Haz

ard

/Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Indu

stri

al c

hem

ical

s in

raw

wat

er:

• Sp

ill in

cat

chm

ent

• Ex

ceed

ance

of

desi

gn u

pper

lim

it•

Exce

edan

ce o

f de

sign

rat

e of

ch

ange

• N

ot d

etec

ted

by m

onito

ring

sy

stem

s•

Nor

mal

tre

ated

w

ater

tar

get

wro

ngly

spe

cifi e

d

• A

lum

iniu

m•

Die

sel

• C

hrom

ium

• M

ercu

ry•

Her

bici

des

(eg.

atra

zine

)•

Pest

icid

es•

Lead

• M

TBE

• M

anga

nese

• C

lean

ing

agen

ts

(eg.

xyle

ne)

• Ex

tent

of u

natt

ende

d pl

ant

oper

atio

n•

His

tory

of d

etec

tion

of u

nusu

al

chem

ical

s in

raw

/ tr

eate

d w

ater

• R

ate

of c

hang

es•

Dur

atio

n an

d m

agni

tude

of p

ossi

ble

upst

ream

spi

lls•

Abi

lity

to d

etec

t ch

emic

als

• N

atur

e of

che

mic

als

and

the

abi

lity

to

rem

ove

with

tre

atm

ent

• O

ther

acc

ompa

nyin

g ha

zard

s (e

g. ta

ste

and

odou

r co

mpo

unds

) •

Abi

lity

to s

top

the

plan

t, or

use

al

tern

ativ

e su

pply

• C

usto

mer

sen

sitiv

ity /

outr

age,

nu

mbe

r of

cus

tom

ers

affe

cted

• Po

ssib

ility

of d

ilutio

n or

ble

ndin

g do

wns

trea

m•

Lega

l res

pons

ibili

ty a

nd li

abili

ty•

See

Fact

She

ets

1 -

13 r

egar

ding

ca

tchm

ents

and

res

ervo

irs

to

dete

rmin

e up

stre

am r

isks

• A

dditi

onal

PA

C /

GA

C•

Add

ition

al c

oagu

lant

• Pl

ant

slow

dow

n•

Plan

t sh

utdo

wn

• Sw

itch

to a

ltern

ativ

e su

pply

• C

usto

mer

and

hea

lth d

epar

tmen

t no

tifi c

atio

ns

• D

evel

op r

apid

not

ifi ca

tion

syst

em fo

r ch

emic

al s

pills

with

in t

he

catc

hmen

t•

Dev

elop

inci

dent

man

agem

ent

and

emer

genc

y re

spon

se

proc

edur

es•

Educ

ate

cust

omer

s ab

out

chem

ical

ris

ks (

eg. i

f che

mic

al le

vel i

s be

low

tar

get,

then

wat

er is

oka

y)•

Mon

itor

for

unus

ual c

usto

mer

com

plai

nts

Impr

ove

mon

itori

ng (

raw

w

ater

, tre

ated

wat

er, u

pper

cat

chm

ent)

• D

esig

n st

agin

g of

add

ition

al W

TP

syst

ems

• En

sure

rap

id a

nd a

ccur

ate

chem

ical

mea

sure

men

t av

aila

ble

• En

sure

app

ropr

iate

pro

toco

ls a

nd p

roce

dure

s ex

ist

for:

• sw

itchi

ng t

o al

tern

ativ

e su

pply

• au

tom

atic

pla

nt s

hutd

own

• re

duce

d pl

ant fl o

w•

Esta

blis

h su

itabl

e cr

itica

l lim

its•

Kee

p re

cord

s of

inci

dent

s

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

• 14

. WT

P R

elia

bilit

y

Use

ful

We

bsi

tes:

• ht

tp://

ww

w.ia

nr.u

nl.e

du/p

ubs/

wat

er/g

1282

.htm


50

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

• 14

. WT

P R

elia

bilit

y•

22. W

TP

Des

ign

Cap

abili

ty -

Tur

bidi

ty•

23. D

isin

fect

ion

Syst

em –

Rel

iabi

lity

• 24

. Dis

infe

ctio

n Sy

stem

- D

esig

n C

apab

ility

Use

ful

Lit

era

ture

:•

Gel

drei

ch, E

E M

icro

biol

ogic

al q

ualit

y of

sou

rce

wat

ers

for

wat

er s

uppl

y. In

: McF

ette

rs, G

A (

ed),

Dri

nkin

g w

ater

mic

robi

olog

y. Sp

ring

er-V

erla

g, N

ew Y

ork,

USA

. 199

0•

Ros

e, J.

B. O

ccur

renc

e an

d C

ontr

ol o

f Cry

ptos

pori

dium

in W

ater

. In:

Adv

ance

s in

Dri

nkin

g Wat

er M

icro

biol

ogy

Res

earc

h. M

cFet

ers,

G.A

. (ed

.), S

cien

ce T

ech.

Mad

ison

, WI.

p. 2

90-3

17, 1

989.

• Le

Che

valli

er, M

. W. a

nd N

orto

n, W

. D. G

iard

ia a

nd C

rypt

ospo

ridi

um in

raw

and

fi ni

shed

wat

er. A

mer

ican

Wat

er W

orks

Ass

ocia

tion

Jour

nal 8

7(9)

: 54-

68, 1

995.

Use

ful

We

bsi

tes:

• ht

tp://

ww

w.ia

nr.u

nl.e

du/p

ubs/

wat

er/g

989.

htm

20

. WT

P D

esi

gn C

apab

ilit

y –

Mic

rob

iolo

gica

l C

on

tam

inat

ion

(P

ath

oge

ns)

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d

and

se

veri

ty

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Mic

robi

olog

ical

co

ntam

inat

ion

in r

aw

wat

er fr

om:

• Ex

ceed

ance

of d

esig

n up

per

limit

• N

ot d

etec

ted

by

mon

itori

ng s

yste

ms

• Pa

ssth

roug

h af

ter

trea

tmen

t pr

oces

s fa

ilure

• N

orm

al t

reat

ed

wat

er t

arge

t w

rong

ly

spec

ifi ed

•

Path

ogen

s as

soci

ated

w

ith in

effe

ctiv

e co

agul

atio

n re

sulti

ng

from

sto

rm e

vent

s w

ith h

igh

turb

idity

/ co

lour

and

rap

id p

H /

alka

linity

cha

nges

• M

icro

biol

ogic

al

cont

amin

atio

n -

bact

eria

, vir

uses

, pr

otoz

oa

- se

edin

g of

biofi l

ms

in t

he d

istr

ibut

ion

syst

em

- ac

cum

ulat

ion

of

prot

ozoa

in b

iofi l

ms

• Ta

ste

and

odou

r co

mpo

unds

• A

bilit

y to

det

ect

path

ogen

s an

d/or

indi

cato

r or

gani

sms

• Ex

tent

of r

emot

e m

onito

ring

/ co

ntro

l and

of

unat

tend

ed o

pera

tion

of p

lant

• D

urat

ion

and

mag

nitu

de o

f ine

ffect

ive

coag

ulat

ion

and fi l

trat

ion

• N

atur

e of

pat

hoge

ns•

Ass

ocia

ted

effe

cts,

eg. s

ensi

tivity

to

high

pos

t ch

lori

natio

n in

ter

ms

of d

owns

trea

m t

aste

and

od

our

• A

bilit

y to

rem

ove

by t

reat

men

t, eg

. fi lt

er e

ffi ci

ency

, av

aila

ble

cont

act

time

• A

bilit

y to

sto

p pl

ant

• A

vaila

bilit

y of

alte

rnat

ive

supp

ly•

Illne

ss s

urve

illan

ce r

esul

ts a

nd s

urve

y la

g tim

e•

Cus

tom

er o

utra

ge, n

umbe

r of

cus

tom

ers

affe

cted

• Se

nsiti

vity

of c

usto

mer

s to

pat

hoge

ns, e

g. ho

spita

ls,

beve

rage

man

ufac

ture

rs•

Sens

itivi

ty o

f cus

tom

ers

to t

reat

men

t by

-pro

duct

s, eg

. hig

h po

st c

hlor

inat

ion

• Le

gal r

espo

nsib

ility

and

liab

ility

• Se

e Fa

ct S

heet

s 1-

13 r

egar

ding

cat

chm

ents

and

re

serv

oirs

to

dete

rmin

e up

stre

am t

urbi

dity

and

pa

thog

en r

isks

• C

hang

e / i

ncre

ase

disi

nfec

tant

do

se•

Jar

test

ing

to o

ptim

ise

coag

ulat

ion

• Pl

ant fl o

wra

te t

urnd

own

• Pl

ant

shut

dow

n w

hile

sto

rm

even

t pa

sses

• U

se a

ltern

ativ

e su

pply

• Br

ing

addi

tiona

l fi lt

ers

and

sedi

men

tatio

n un

its o

n lin

e•

Filte

r to

was

te w

hen fi l

ter

turb

idity

occ

urs

• Ea

rly

back

was

hing

wel

l bef

ore

part

icle

or

turb

idity

ris

es in

fi l

tere

d w

ater

• Pr

e-ch

lori

natio

n as

wel

l as

post

-ch

lori

natio

n

• En

sure

the

follo

win

g ha

ve b

een

cons

ider

ed a

nd

asse

ssed

:•

mon

itori

ng (

eg. o

f con

tinuo

us r

aw w

ater

, se

ttle

d w

ater

and

tre

ated

wat

er t

urbi

dity

)•

upst

ream

pre

vent

ive

mea

sure

s (e

g se

lect

so

urce

s, se

lect

ive

with

draw

al, a

void

sho

rt

circ

uitin

g, av

oid

pollu

ted

stor

mw

ater

and

se

wag

e tr

eatm

ent

plan

t)•

unde

rsta

ndin

g of

hig

h pa

thog

en c

halle

nge

cond

ition

s in

raw

wat

er a

nd e

ffect

ive

resp

onse

s an

d ac

tions

at

the

WT

P•

disi

nfec

tion

relia

bilit

y•

spee

d an

d ac

cura

cy o

f pat

hoge

n m

easu

rem

ent

• D

esig

n st

agin

g of

add

ition

al W

TP

syst

ems

• R

etrofi t

pla

nt t

o in

clud

e oz

one

and

GA

C s

tage

s or

fi l

tere

d w

ater

UV

• En

sure

app

ropr

iate

pro

toco

ls a

nd o

pera

tiona

l pr

oced

ures

exi

st fo

r:•

use

of a

ltern

ativ

e su

pplie

s•

auto

mat

ic p

lant

shu

tdow

n•

inci

dent

and

em

erge

ncy

man

agem

ent

• re

cord

ing

of in

cide

nts

• no

tifi c

atio

n fr

om h

ealth

aut

hori

ties

of il

lnes

ses

• m

aint

aini

ng o

ptim

um c

oagu

latio

n (ja

r te

sts)

an

d di

sinf

ectio

n (p

lann

ed m

aint

enan

ce)

• Ill

ness

sur

veill

ance

(ra

pid

feed

back

req

uire

d)•

Boil

wat

er n

otic

es•

Educ

ate

cust

omer

s ab

out

path

ogen

ris

ks (

eg. i

f pa

thog

en le

vel i

s be

low

tar

get,

then

wat

er is

oka

y)


51

21

. WT

P D

esi

gn C

apab

ilit

y -

Tas

te a

nd

Od

ou

rS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Poor

tas

te a

nd o

dour

in

raw

wat

er:

• Ex

ceed

ance

of d

esig

n up

per

limit

• Ex

ceed

ance

of d

esig

n ra

te o

f cha

nge

• La

ck o

f ade

quat

e m

onito

ring

and

pr

edic

ting

syst

ems

• N

orm

al t

reat

ed

wat

er t

arge

t w

rong

ly

spec

ifi ed

• Ta

ste

and

odou

r co

mpo

unds

- fr

om

alga

e

• M

icro

biol

ogic

al

cont

amin

atio

n -

from

in

crea

sed

disi

nfec

tant

de

cay

rate

•

Cya

noba

cter

ia•

Dis

infe

ctio

n by

prod

ucts

• C

hem

ical

co

ntam

inat

ion

- fr

om in

dust

rial

ch

emic

al r

esid

ues

(eg.

dies

el, p

heno

ls)

and

disi

nfec

tion

bypr

oduc

ts

• D

urat

ion

of u

natt

ende

d pl

ant

oper

atio

n•

Thr

esho

ld o

f tas

te a

nd o

dour

• D

urat

ion

and

mag

nitu

de o

f eve

nt•

Nat

ure

of t

aste

and

odo

ur a

nd a

bilit

y to

rem

ove

by t

reat

men

t•

Oth

er a

ccom

pany

ing

haza

rds

(eg.

turb

idity

, pat

hoge

ns)

• A

bilit

y to

sto

p pl

ant

or u

se a

ltern

ativ

e su

pply

• Su

pern

atan

t an

d w

ash

wat

er r

ecyc

le

optio

ns•

Cus

tom

er s

ensi

tivity

, num

ber

and

type

of c

usto

mer

s af

fect

ed (

eg. h

otel

s, to

uris

t re

sort

s)•

Cus

tom

er p

erce

ptio

ns o

f sud

den

chan

ges

in t

aste

and

odo

ur•

Poss

ibili

ty o

f dilu

tion

or b

lend

ing

dow

nstr

eam

• Se

e Fa

ct S

heet

s 1-

13 r

egar

ding

ca

tchm

ents

and

res

ervo

irs

to

dete

rmin

e up

stre

am t

aste

and

odo

ur

risk

s

• Pr

e-ch

lori

natio

n•

Add

ition

of P

AC

• A

dditi

on o

f ozo

ne•

Add

ition

al p

ost-

chlo

rina

tion

• A

dditi

onal

coa

gula

nt•

Red

uce

or s

top

supe

rnat

ant

recy

cle(

slud

ge la

goon

) •

Plan

t sl

owdo

wn

/ shu

tdow

n•

Switc

h to

alte

rnat

ive

supp

ly•

Dis

solv

ed a

ir fl

otat

ion

to r

emov

e al

gae

cells

• Fi

ltere

d w

ater

run

thr

ough

GA

C

bed

• M

onito

r cu

stom

er c

ompl

aint

s•

Det

erm

ine

leve

l of c

usto

mer

sen

sitiv

ity t

o ch

ange

s in

tas

te a

nd

odou

r•

Dev

elop

rap

id a

nd a

ccur

ate

tast

e an

d od

our

mea

sure

men

t pr

actic

es•

Esta

blis

h ri

sk b

ased

cri

teri

a fo

r th

e le

vel o

f tre

atm

ent

avai

labl

e at

th

e W

TP

• D

esig

n st

agin

g of

add

ition

al W

TP

equi

pmen

t•

Mon

itor

alga

e sp

ecie

s in

res

ervo

ir /

rive

r up

stre

am o

f the

pla

nt•

Ensu

re a

ppro

pria

te p

roto

cols

and

ope

ratio

nal p

roce

dure

s ex

ist

for: •

switc

hing

to

alte

rnat

ive

supp

ly•

auto

mat

ic p

lant

shu

tdow

n•

redu

ced

plan

t fl o

w•

inci

dent

and

em

erge

ncy

man

agem

ent

• re

port

ing

of in

cide

nts

• cu

stom

er n

otifi

catio

n•

Rev

iew

rec

yclin

g pr

actic

es a

nd c

ontin

genc

ies

for

shor

t te

rm

shut

dow

n•

Esta

blis

h su

itabl

e co

ntro

l poi

nts

/ lim

its

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

• 14

. WT

P R

elia

bilit

y•

23. D

isin

fect

ion

Syst

em –

Rel

iabi

lity

• 24

. Dis

infe

ctio

n Sy

stem

- D

esig

n C

apab

ility

Use

ful

Lit

era

ture

:•

Ritt

man

, D. a

nd T

arqu

in A

. J. U

se o

f Chl

orin

e D

ioxi

de fo

r D

isin

fect

ion

and

Tast

e an

d O

dour

Con

trol

. Pub

lic W

orks

Jour

nal,

1993

.


52

22

. WT

P D

esi

gn C

apab

ilit

y -

Tu

rbid

ity

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Turb

idity

in r

aw w

ater

:•

Exce

edan

ce o

f des

ign

uppe

r lim

it•

Exce

edan

ce o

f des

ign

rate

of c

hang

e•

Nor

mal

tre

ated

w

ater

tar

get

wro

ngly

sp

ecifi

ed•

Filte

r br

eakt

hrou

gh

not

dete

cted

• M

atur

atio

n sp

ike

afte

r fi l

ter

back

was

h to

o lo

ng /

high

• Tu

rbid

ity•

Che

mic

al

cont

amin

atio

n -

alum

iniu

m•

Mic

robi

olog

ical

co

ntam

inat

ion

• T

imin

g of

haz

ard

- e

g af

ter

hour

s du

ring

sto

rm e

vent

s, du

ring

pla

nt

star

tup,

aft

er b

ackw

ash

• Pr

esen

ce o

f ope

rato

r•

Flow

rate

cha

nges

of p

lant

•

Back

was

h ef

fect

iven

ess

• Se

ttlin

g un

it lo

adin

g•

Flas

h m

ixin

g in

tens

ity•

Oth

er a

ccom

pany

ing

haza

rds

(eg.

mic

robe

s)

• Tu

rbid

ity, c

olou

r, pH

, and

alk

alin

ity

vari

atio

n in

raw

wat

er•

Pres

ence

of p

roto

zoa

in t

he r

aw w

ater

• C

hara

cter

istic

s of

fl oc

tur

bidi

ty (

eg.

size

, fra

gilit

y, se

ttle

abili

ty)

• Po

ssib

ility

of t

he n

orm

al t

arge

t be

ing

set

too

high

• Se

e Fa

ct S

heet

s 1

– 13

reg

ardi

ng

catc

hmen

ts a

nd r

eser

voir

s to

de

term

ine

upst

ream

tur

bidi

ty r

isks

• C

ontin

uous

tur

bidi

ty m

onito

r at

ea

ch fi

lter

with

ala

rm•

Dec

reas

e fl o

wra

te•

Adj

ust

coag

ulan

t•

Incr

ease

num

ber

of o

nlin

e cl

arifi

ers

/ fi lt

ers

• R

educ

e su

pern

atan

t (s

ludg

e la

goon

) re

use

• D

uty

/ sta

ndby

coa

gula

nt d

osin

g eq

uipm

ent

• Fi

lter

to w

aste

cap

abili

ty•

Shut

off

plan

t

• En

sure

ade

quat

e m

onito

ring

is c

arri

ed o

ut (

cont

inuo

us r

aw a

nd

sett

led

wat

er, fi

lter

ed w

ater

at

each

fi lte

r)•

Impr

ove

rem

ote

cont

rol o

f pla

nt fl

ow r

ate,

coa

gula

nts, fi l

ter

aid

and

back

was

h cy

cle

• M

aint

ain

upst

ream

pre

vent

ive

mea

sure

s (e

g se

lect

ive

with

draw

al,

sele

ct s

ourc

es, a

void

sho

rt c

ircu

iting

)•

Impr

ove:

• co

agul

ant

/ coa

gula

tion

• fl o

c pH

con

trol

• fl a

sh m

ixin

g• fi l

ter

aid

poly

mer

, set

tling

aid

pol

ymer

• U

pgra

de W

TP:

• ad

d cl

arifi

er s

tage

• in

crea

se n

umbe

r of

fi lte

rs•

Ensu

re a

ppro

pria

te p

roto

cols

and

ope

ratio

nal p

roce

dure

s ex

ist

for:

• al

tern

ativ

e su

pply

• au

tom

atic

shu

tdow

n•

redu

ced fl o

w•

rem

ote

plan

t op

erat

ion

• al

teri

ng c

oagu

lant

and

pol

ymer

dos

es (

jar

test

s)•

inci

dent

and

em

erge

ncy

man

agem

ent

• re

cord

ing

and

repo

rtin

g of

inci

dent

s

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

• 14

. WT

P R

elia

bilit

y•

23. D

isin

fect

ion

Syst

em –

Rel

iabi

lity

• 24

. Dis

infe

ctio

n Sy

stem

- D

esig

n C

apab

ility

Use

ful

Lit

era

ture

:•

Tse

ng, T

., Se

gal,

B.D

. and

Edw

ards

, M. I

ncre

asin

g al

kalin

ity t

o re

duce

tur

bidi

ty. A

WW

A Jo

urna

l, 92

(9),

2000

.•

Hof

f, J.C

. The

rel

atio

nshi

p of

tur

bidi

ty t

o di

sinf

ectio

n of

pot

able

wat

er. P

rese

nted

at

Con

fere

nce

on t

he E

valu

atio

n of

Mic

robi

olog

ical

Sta

ndar

ds fo

r D

rink

ing W

ater

. US

Envi

ronm

enta

l Pro

tect

ion

Age

ncy,

Offi

ce o

f Wat

er S

uppl

y W

ashi

ngto

n D

C. 1

977.


53

23

. Dis

infe

ctio

n S

yste

m R

eli

abil

ity

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Failu

re o

f:•

Dis

infe

ctan

t do

sing

•

Dos

ing

of p

H

corr

ectio

n ch

emic

al•

Pow

erA

lso:

• C

onta

min

ated

ch

emic

als

• Eq

uipm

ent

brea

kdow

n•

Inad

equa

te a

utom

atic

co

ntro

l or

diag

nost

ics

• La

ck o

f bac

kup

dosi

ng,

tele

met

ry, a

nd p

ower

su

pply

equ

ipm

ent

• M

icro

biol

ogic

al

cont

amin

atio

n

- i

nclu

ding

via

ble

infe

ctiv

e ba

cter

ia,

viru

ses,

prot

ozoa

• Ta

ste

and

odou

r co

mpo

unds

• D

irty

wat

er d

ue t

o sl

ough

ing

• A

vaila

bilit

y of

aut

o st

andb

y / b

acku

p do

sing

and

bac

kup

pow

er•

Like

lihoo

d an

d du

ratio

n of

pow

er fa

ilure

• G

ener

al e

quip

men

t m

aint

enan

ce c

ondi

tion

• Li

kelih

ood

of t

elem

etry

failu

re•

Like

lihoo

d of

losi

ng c

ontr

ol (

eg o

f PLC

)•

Ope

rato

r at

tend

ance

and

tra

inin

g -

abili

ty

to u

nder

stan

d te

lem

eter

ed in

form

atio

n an

d to

ant

icip

ate

and

reac

t co

rrec

tly t

o fa

ilure

ris

k•

Deg

ree

of c

ontr

ol o

f inl

et w

ater

fl ow

and

qu

ality

• M

ean

time

betw

een

failu

res

• D

urat

ion

of fa

ilure

s•

Cus

tom

er p

opul

atio

n do

wns

trea

m o

f the

ta

nk /

pipe

line

• Pr

oxim

ity o

f cus

tom

ers

dow

nstr

eam

of

the

tank

/ pi

pelin

e•

Dri

ft o

f res

idua

l ana

lyse

r•

Ala

rms

• In

cide

nt a

nd e

mer

genc

y re

spon

se

prot

ocol

s in

pla

ce a

nd t

heir

effe

ctiv

enes

s

• A

utom

atic

res

idua

l tri

m•

Aut

omat

ic fl

ow p

acin

g•

Mon

itori

ng /

alar

ms

for:

- p

H

-

fl ow

- r

esid

ual d

isin

fect

ant

- t

urbi

dity

- lo

w fl

ow (

for

liqui

ds)

• U

nint

erru

pted

Pow

er S

uppl

y (U

PS)

for

cont

inuo

us m

onito

ring

•

Wat

er fl

ow c

ontr

ol•

Stan

dby

and

auto

cha

ngeo

ver

• A

utom

atic

pla

nt s

hutd

own

• A

ltern

ativ

e w

ater

sou

rce

• Bo

il w

ater

not

ice

• D

ump

wat

er

• C

onfi r

m c

onta

ct t

ime

unde

r al

l ope

ratio

nal r

egim

es•

Ana

lyse

failu

re m

odes

, and

the

ir e

ffect

s on

con

tact

tim

e•

Add

if n

ot p

rese

nt:

• au

tom

atic

dia

lout

/ te

lem

etry

• ba

ckup

/ st

andb

y eq

uipm

ent

• un

inte

rrup

ted

pow

er s

uppl

y•

cont

inuo

us t

ank

leve

l / w

eigh

t m

onito

ring

• lo

w fl

ow a

larm

• lo

w r

esid

ual a

larm

•

low

pre

ssur

e al

arm

• re

mot

e do

se a

djus

tmen

t•

Con

duct

HA

ZO

P / H

AZ

AN

to

confi

rm

rel

iabi

lity

• D

uplic

ate

dosi

ng li

nes

• In

stal

l vis

ual i

nspe

ctio

n fa

cilit

y to

confi r

m d

osin

g •

Ensu

re a

ppro

pria

te p

roto

cols

and

ope

ratio

nal p

roce

dure

s fo

r: • m

aint

enan

ce•

trai

ning

of p

erso

nnel

• co

rrec

t ch

emic

al d

eliv

erie

s•

inci

dent

and

em

erge

ncy

man

agem

ent

• re

cord

ing

and

repo

rtin

g of

inci

dent

s•

Boil

wat

er n

otifi

catio

n pr

oced

ures

• C

usto

mer

sen

sitiv

ity a

naly

sis

Oth

er

rela

ted

Fac

t S

he

ets

: •

WT

P D

esig

n C

apab

ility

Fac

t Sh

eets

14

– 22

.•

24. D

isin

fect

ion

Syst

em -

Des

ign

Cap

abili

ty

Use

ful

Lit

era

ture

:•

AW

WA

Wat

er Q

ualit

y D

ivis

ion

Dis

infe

ctio

n Sy

stem

s C

omm

ittee

, Com

mitt

ee r

epor

t: D

isin

fect

ion

at s

mal

l sys

tem

s. A

WW

A Jo

urna

l 92(

5), 2

000.

• W

inds

or S

ung

et a

l., M

odel

ling

DBP

form

atio

n. A

WW

A Jo

urna

l 92(

5), 2

000.


54

24

. Dis

infe

ctio

n S

yste

m D

esi

gn C

apab

ilit

yS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Failu

re t

o di

sinf

ect

wat

er a

dequ

atel

y du

e to

:•

requ

ired

dos

e ex

ceed

ing

desi

gn

uppe

r lim

it•

rate

of c

hang

e in

req

uire

d do

se

exce

edin

g de

sign

lim

it•

inco

rrec

t no

rmal

do

se u

sed

• in

corr

ect

disi

nfec

tant

us

ed

• M

icro

biol

ogic

al

cont

amin

atio

n

- i

nclu

ding

via

ble

infe

ctiv

e ba

cter

ia,

viru

ses,

prot

ozoa

• C

hem

ical

co

ntam

inat

ion

-

fr

om d

isin

fect

ion

bypr

oduc

ts (

DBP

’s)

• T

imin

g of

pro

blem

s (a

fter

noon

, pea

k,

nigh

t)?

Pres

ence

of o

pera

tor?

•

Rat

e of

cha

nge

in fl

ow r

ate

• D

urat

ion

of e

vent

s ou

tsid

e de

sign

lim

its•

Mag

nitu

de o

f con

tam

inat

ion

even

t•

Num

ber

of c

usto

mer

s w

here

con

tact

tim

e is

insu

ffi ci

ent

• Sh

ort

circ

uitin

g ef

fect

s w

ithin

con

tact

ta

nks

• W

heth

er c

ontin

uous

mon

itori

ng a

nd

alar

ms

exis

t fo

r in

dica

tors

or

cont

rols

(e

g. au

to d

uty/

stan

dby, fl o

w p

ace,

and

re

sidu

al t

rim

)•

Seve

rity

/ fr

eque

ncy

of t

urbi

dity

blip

s•

pH o

f wat

er•

Shie

ldin

g (t

urbi

dity

and

col

our)

• R

esid

ual d

ecay

rat

es•

Com

bina

tion

of d

isin

fect

ants

• Ty

pe o

f dis

infe

ctan

t•

Type

/ pr

opor

tion

of p

atho

gens

left

• Si

ze /

prox

imity

/ se

nsiti

vity

of

dow

nstr

eam

pop

ulat

ions

• Po

ssib

ility

of t

he n

orm

al t

arge

t be

ing

set

too

high

or

too

low

• Se

quen

ce o

f dis

infe

ctan

ts u

sed

(eg.

prefi

lter

chl

orin

e, a

nd p

ostfi

lter

ch

lori

ne, U

V, c

hlor

amin

e)•

See

Fact

She

ets

1 –

13 t

o de

term

ine

upst

ream

tur

bidi

ty r

isks

• M

onito

r an

d al

arm

dis

infe

ctan

t re

sidu

al a

nd fl

ow r

ate

to

cont

inuo

usly

ach

ieve

req

uire

d do

se

rate

and

/or

cont

act

time

• M

onito

r su

rrog

ate

effe

ctiv

enes

s in

dica

tors

(eg

. par

ticle

s, tu

rbid

ity)

• Se

t tr

eate

d w

ater

tar

gets

ap

prop

riat

ely

eg in

dica

tors

for

path

ogen

s su

ch a

s co

lifor

ms

and

spor

es (

log

kill)

• C

hang

e di

sinf

ecta

nt d

ose

/ typ

e to

su

it pa

thog

en a

nd D

BP li

mits

• Pr

ovid

e ad

ditio

nal c

onta

ct t

ime

• A

void

sup

erna

tant

(sl

udge

lago

on)

recy

cle

• Sh

ut o

ff su

pply

whe

n ra

w w

ater

ex

ceed

s lim

its a

t w

hich

effe

ctiv

e di

sinf

ectio

n is

ass

ured

(eg

tur

bidi

ty >

5

NT

U)

• Ba

ck u

p po

wer

sup

ply

for

grav

ity

wat

er s

uppl

y si

tuat

ions

• D

owns

trea

m c

orre

ctiv

e ac

tions

suc

h as

dum

ping

wat

er o

r re

chlo

rina

tion

• Se

e Fa

ct S

heet

s 1

– 22

for

deta

ils o

f up

stre

am c

ontr

ols

whi

ch c

an r

educ

e th

e ri

sk o

f hig

h le

vels

of m

icro

bial

co

ntam

inat

ion

• U

nder

take

ana

lysi

s of

con

tact

tim

e an

d de

cay

rate

s•

Und

erst

and

the

mix

, ran

ge, a

nd fa

ctor

s re

sulti

ng in

hig

h le

vels

of p

atho

gens

in t

he u

pstr

eam

sys

tem

• U

nder

stan

d th

e do

wns

trea

m a

rran

gem

ents

and

the

impa

ct

of d

isin

fect

ion

• Im

prov

e:•

mon

itori

ng -

eg.

prov

ide

cont

inuo

us m

onito

ring

for

disi

nfec

tant

res

idua

l and

cat

chm

ent

fact

ors

• re

mot

e co

ntro

l / a

utom

atio

n•

upst

ream

con

trol

s -

eg

sele

ctiv

e w

ithdr

awal

, sel

ect

sour

ces,

avoi

d sh

ort

circ

uitin

g, fi l

teri

ng•

coag

ulan

t / c

oagu

latio

n / fi

ltra

tion

optim

isat

ion

• pH

con

trol

• co

ntro

l of t

urbi

dity

, col

our

and

orga

nics

•

back

up

pow

er s

uppl

y•

Incr

ease

con

tact

tim

e•

Red

uce

turb

idity

tar

get

leve

l•

Alte

r di

sinf

ecta

nt d

ose

conc

entr

atio

n•

Cha

nge

disi

nfec

tant

to

suit

path

ogen

s an

d w

ater

qua

lity

cond

ition

s•

Ensu

re a

ppro

pria

te p

roto

cols

and

ope

ratio

nal p

roce

dure

s fo

r: • al

tern

ativ

e su

pply

• au

tom

atic

shu

tdow

n•

auto

mat

ic r

educ

ed fl

ow (

incr

ease

con

tact

tim

e)•

supe

rnat

ant

recy

lcle

• re

mot

e pl

ant

oper

atio

n•

inci

dent

and

em

erge

ncy

man

agem

ent

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ting

to C

atch

men

ts a

nd R

eser

voir

s: 1

– 13

• Fa

ct S

heet

s re

latin

g to

WT

P D

esig

n C

apab

ility

: 14

- 22

Use

ful

Lit

era

ture

:•

Whi

te, G

.C. H

andb

ook

of C

hlor

inat

ion

and

alte

rnat

ive

disi

nfec

tant

s. 4t

h Ed

ition

, Wile

y-In

ters

cien

ce, 1

998.


55

25

. Co

nta

min

atio

n o

f S

erv

ice

Re

serv

oir

s an

d T

ank

s w

ith

Flo

atin

g C

ove

rsS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Acc

ess

by a

nim

als

-in

clud

ing

bird

s, es

peci

ally

th

roug

h ov

erfl o

w r

elie

f po

ints

, air

ven

ts a

nd a

cces

s ha

tche

s

• Mic

robi

olog

ical

co

ntam

inat

ion

• H

ighe

r ri

sk t

han

for

rese

rvoi

rs o

r ta

nks

with

fi xe

d co

vers

as

ther

e is

a g

reat

er

likel

ihoo

d of

ani

mal

s/bi

rds

beco

min

g tr

appe

d

• Ins

ect

proo

f scr

eens

at

air

vent

s an

d ov

erfl o

w p

oint

s• G

ood

seal

s at

acc

ess

hatc

hes

• Ins

pect

ion

• Rev

iew

rec

ords

and

exp

erie

nce

rega

rdin

g ac

cess

of a

nim

als

and

bird

s

Mic

robi

al g

row

th u

nder

co

ver

• Mic

robi

olog

ical

co

ntam

inat

ion

• Tas

te a

nd o

dour

co

mpo

unds

• Mic

robi

olog

ical

gro

wth

may

be

wor

se

whe

re c

hlor

amin

atio

n is

use

d as

di

sinf

ecta

nt

• Hig

h ch

lori

ne r

esid

ual (

> 1

mg/

l)• R

egul

ar c

lean

ing

and

mai

nten

ance

• Lim

ited

rese

arch

see

ms

to s

ugge

st r

equi

rem

ent

to

keep

chl

orin

e re

sidu

al a

bove

1.0

mg/

L in

bas

in p

rovi

ded

dete

ntio

n tim

es a

re r

elat

ivel

y lo

w a

nd o

rgan

ic c

onte

nt o

f th

e w

ater

is lo

w (

eg fi

ltere

d w

ater

hel

d fo

r <

2 d

ays)

Acc

ess

by h

uman

s

-va

ndal

ism

lead

ing

to a

pu

nctu

red

cove

r

• Mic

robi

olog

ical

co

ntam

inat

ion

• Che

mic

al c

onta

min

atio

n -in

dust

rial

con

tam

inan

ts

• Loc

atio

n of

bas

in (

eg a

void

pes

ticid

e sp

ray

area

s, he

avily

pop

ulat

ed a

reas

)• P

oten

tial f

or h

uman

acc

ess

and

va

ndal

ism

• Sec

urity

fenc

e• R

egul

ar in

spec

tions

and

m

onito

ring

• App

ropr

iate

des

ign

of c

over

s to

re

sist

pun

ctur

e by

pro

ject

iles

• Rev

iew

rec

ords

and

his

tory

con

cern

ing

vand

alis

m• E

nsur

e re

gula

r in

spec

tions

/ m

onito

ring

are

tak

ing

plac

e

Ingr

ess

of c

onta

min

ated

gr

ound

wat

er (

for

in-

grou

nd c

oncr

ete

tank

s)

• Che

mic

al c

onta

min

atio

n -in

dust

rial

con

tam

inan

ts• M

icro

biol

ogic

al

cont

amin

atio

n

• Loc

al w

ater

tab

le le

vel a

nd w

ater

qua

lity

• Ext

ent

of d

raw

and

fi ll

of b

asin

• Dis

infe

ctan

t re

sidu

al le

vel i

n ba

sin

• Con

stru

ctio

n of

und

er fl

oor

slot

ted

pipe

dra

inag

e sy

stem

w

ith in

spec

tion

pits

and

fl ow

m

easu

rem

ent

/ mon

itori

ng

syst

em• R

egul

ar in

spec

tion

of li

ner

for

hole

s (e

spec

ially

aft

er c

lean

ing)

• Rev

iew

gro

undw

ater

dep

th a

nd q

ualit

y in

the

are

a re

lativ

e to

bas

e of

tan

k• A

void

loca

ting

in h

igh

wat

er t

able

are

as• M

aint

ain

adeq

uate

dis

infe

ctan

t re

sidu

al le

vels

• Des

ign

with

ext

erna

l dra

inag

e sy

stem

, and

mon

itor

its

effe

ctiv

enes

s

Scou

r of

bot

tom

sed

imen

ts

duri

ng h

igh/

low

fl ow

pe

riod

s

• Tur

bidi

ty• M

icro

biol

ogic

al

cont

amin

atio

n• C

olou

r• I

ron

• Alu

min

ium

(po

st

trea

tmen

t fl o

ccul

atio

n)

• Fre

quen

cy o

f cle

anin

g• P

eak

to a

vera

ge fl

ow r

ate

ratio

• Sus

pend

ed m

atte

r co

ncen

trat

ion

of

infl o

w• I

nlet

/out

let

geom

etry

• Use

div

ers

to c

lean

to

avoi

d th

e ne

ed t

o de

wat

er a

nd infl a

te

cove

r

• Rec

ord

sedi

men

t bu

ildup

rat

e an

d cl

ean

whe

n ap

prop

riat

e de

pth

pred

icte

d (e

g 15

-30

mm

dep

th)

• Che

ck c

ompo

sitio

n of

sed

imen

t (A

l, Fe

, Mn,

Si)

to

dete

rmin

e po

ssib

le s

ourc

es

Ingr

ess

of r

ainw

ater

-th

roug

h sp

lits

in c

over

or

drow

ned

acce

ss h

atch

es

• M

icro

biol

ogic

al

cont

amin

atio

n • N

atur

al o

rgan

ic m

atte

r• C

hem

ical

con

tam

inat

ion

-

eg. t

race

pes

ticid

es, l

ead

• Loc

al le

af li

tter

load

ing

• His

tory

of b

lock

ages

• Reg

ular

insp

ectio

n• R

emov

e su

rrou

ndin

g tr

ees

that

pro

duce

a lo

t of

leaf

litt

er

(eg.

pine

tre

es)

whi

ch c

an c

log

rain

wat

er r

emov

al p

umps

• Use

div

ers

to d

o cl

eani

ng t

o av

oid

risk

of t

eari

ng c

over

whe

n infl a

ted

• Rev

iew

rec

ords

and

exp

erie

nce

rega

rdin

g ra

infa

ll in

gres

s to

ta

nks.

• Rem

ove

loca

l tre

es c

ausi

ng le

af li

tter

• Effe

ctiv

e de

sign

of r

ainw

ater

rem

oval

sys

tem

with

ala

rm

tele

met

ry

Oth

er

rela

ted

Fac

t S

he

ets

:•

Fact

She

ets

26-2

8 re

latin

g to

Con

tam

inat

ion

of S

ervi

ce R

eser

voir

s an

d Ta

nks

Use

ful

Lit

era

ture

:•

Flex

ible

-mem

bran

e co

vers

and

lini

ngs

for

pota

ble-

wat

er r

eser

voir

s (A

WW

A M

anua

l, M

25).

2nd

Edi

tion,

AW

WA

, 199

6.


56

26

. Co

nta

min

atio

n o

f T

imb

er

Se

rvic

e R

ese

rvo

irs

and

Tan

ks

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Acc

ess

by a

nim

als

in

clud

ing

bird

s• M

icro

biol

ogic

al

cont

amin

atio

n -

fro

m

was

te a

nd d

ead

anim

als

• Ani

mal

s (t

ypic

ally

rod

ents

and

bir

ds)

able

to

get

in t

hrou

gh t

he g

ap b

etw

een

the

wal

ls a

nd t

he r

oof

• Met

al b

and

arou

nd t

ank

stop

s ac

cess

fr

om g

roun

d, b

ut n

ot fo

r bi

rds

nor

via

roof

if o

verh

angi

ng v

eget

atio

n

• Met

al b

and

arou

nd t

ank

to p

reve

nt

acce

ss fr

om g

roun

d le

vel

• Rem

oval

of o

verh

angi

ng v

eget

atio

n ne

ar t

anks

• Int

erna

l lin

er fo

r ta

nk r

oof

• Rev

iew

exp

erie

nce

and

reco

rds

rela

ting

to a

cces

s by

bir

ds a

nd

anim

als

• Ins

tall

a ro

of li

ner, fi r

mly

hel

d do

wn

with

no

gaps

for

anim

al

acce

ss

Leac

hing

of t

imbe

r tr

eatm

ent

chem

ical

s• C

hem

ical

con

tam

inat

ion

-

arse

nic

and

copp

er

cont

amin

atio

n• T

aste

and

odo

ur

com

poun

ds

• Tim

ber

trea

tmen

t ch

emic

als

typi

cally

in

clud

e ar

seni

c or

cop

per

com

poun

ds• I

nter

nal l

iner

for

tank

roo

f • U

se u

ntre

ated

woo

d• I

f roo

f is

trea

ted

and

unlin

ed, e

nsur

e re

gula

r m

onito

ring

of

wat

er fo

r As

/ Cu

esp

ecia

lly a

fter

hea

vy r

ainf

all

• Ins

tall

a ro

of li

ner

Scou

r of

bot

tom

se

dim

ents

dur

ing

high

/low

fl ow

per

iods

• Tur

bidi

ty• M

icro

biol

ogic

al

cont

amin

atio

n• C

olou

r• I

ron

• Alu

min

ium

(po

st

trea

tmen

t fl o

ccul

atio

n)

• Fre

quen

cy o

f cle

anin

g• P

eak

to a

vera

ge fl

ow r

ate

ratio

• Sus

pend

ed m

atte

r co

ncen

trat

ion

of

infl o

w• I

nlet

/out

let

geom

etry

• Em

pty

to w

ithin

50m

m t

hen

was

hdow

n an

d sc

our

to w

aste

• Slo

ping

fl oo

r an

d sc

our

pit

• Hig

h pr

essu

re w

ater

sup

ply

near

by

and

wel

l ven

tilat

ed a

cces

s po

int

• Rec

ord

sedi

men

t bu

ildup

rat

e an

d cl

ean

whe

n ap

prop

riat

e de

pth

pred

icte

d (e

g 15

-30

mm

dep

th)

• Che

ck c

ompo

sitio

n of

sed

imen

t (A

l, Fe

, Mn,

Si)

to d

eter

min

e po

ssib

le s

ourc

es

Oth

er

rela

ted

Fac

t S

he

ets

:•

Fact

She

ets

25, 2

7-28

rel

atin

g to

Con

tam

inat

ion

of S

ervi

ce R

eser

voir

s an

d Ta

nks


57

27

. In

tern

al C

on

tam

inat

ion

of

Se

rvic

e R

ese

rvo

irs

and

Tan

ks

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

der

in a

sses

sin

g lik

elih

oo

d a

nd

sev

erit

y T

ypic

al P

reve

nti

ve

Mea

sure

sS

ugg

esti

on

s fo

r C

on

sid

erat

ion

Sedi

men

t / s

lime

accu

mul

atio

n an

d re

leas

e

• Mic

robi

olog

ical

con

tam

inat

ion

• Tur

bidi

ty• C

hem

ical

con

tam

inat

ion

-m

anga

nese

and

iron

• Whe

ther

res

ervo

ir is

fi rs

t in

line

sto

rage

af

ter

offta

ke fr

om r

iver

/ da

m /

WT

P • N

omin

al d

eten

tion

time

(mor

e se

ttlin

g oc

curs

in t

anks

with

long

er d

eten

tion

time)

• App

ropr

iate

pro

cedu

res

for

rem

ovin

g se

dim

ent

/ slim

es (

min

imis

e st

ir u

p an

d lo

ss)

• Avo

id v

ery

low

leve

l whe

n th

roug

hput

is h

igh

• Reg

ular

cle

anin

g an

d in

spec

tion

• Mai

nten

ance

of c

hlor

ine

resi

dual

• Mai

ntai

n re

cord

s an

d re

view

exp

erie

nce

rega

rdin

g se

dim

ent/

slim

e bu

ild u

p• R

egul

ar in

spec

tions

of w

alls

and

fl oo

r fo

r si

gns

of s

lime

build

up • Est

ablis

h cl

ear

proc

edur

es fo

r cl

eani

ng a

nd e

nsur

e su

perv

isio

n.

Focu

s on

doc

umen

ting

exte

nt o

f bui

ld u

p, un

usua

l dep

osits

an

d m

etho

ds t

o av

oid

sedi

men

t / s

lime

from

ent

erin

g th

e ou

tlet

pipe

• Rev

iew

mic

robi

olog

ical

and

tur

bidi

ty r

esul

ts o

f out

let

wat

er

for

high

val

ues

• Und

erta

ke r

egul

ar c

lean

ing

of r

eser

voir

s w

ith a

ppro

pria

te

proc

edur

es (

reco

mm

end

ever

y 1

– 5

year

s de

pend

ing

on

qual

ity o

f sou

rce

wat

er, fl

ow

thr

ough

tan

k, po

sitio

n in

sys

tem

, et

c). (

1)

Leac

hing

and

co

rros

ion

of

mat

eria

ls in

co

ntac

t w

ith

wat

er

• pH

var

iabi

lity

• Tas

te a

nd o

dour

com

poun

ds• M

icro

biol

ogic

al c

onta

min

atio

n -

from

loss

of d

isin

fect

ant

resi

dual

• Che

mic

al c

onta

min

atio

n -

fr

om H

azar

dous

sub

stan

ces

from

bre

akdo

wn

of s

eala

nts,

liner

s;ch

lori

nate

d by

-pro

duct

s

• Ris

k fr

om m

ater

ials

of c

onst

ruct

ion

depe

nds

on t

he t

ypic

al r

esid

ence

tim

e in

the

tan

k an

d th

e qu

ality

of t

he s

ourc

e w

ater

(eg

har

dnes

s, te

mpe

ratu

re).

Als

o de

pend

s on

the

age

and

in

tegr

ity o

f the

tan

k• C

ertifi

cat

ion

of m

ater

ials

for

pota

ble

use

can

chan

ge o

ver

time

• Use

of m

ater

ials

cer

tifi e

d fo

r po

tabl

e w

ater

use

• Use

of a

ccre

dite

d co

ntra

ctor

s• R

egul

ar in

spec

tion

• Und

erta

ke r

egul

ar in

spec

tion

of t

ank

inte

grity

• Kee

p re

side

nce

times

in t

anks

to

less

tha

n 12

– 2

4 ho

urs

whe

re p

ossi

ble

(eg

by lo

wer

ing

volu

me

duri

ng lo

w d

eman

d pe

riod

s)• U

se b

est

prac

tice

mat

eria

ls in

con

stru

ctio

n of

new

tan

ks

Vari

able

re

side

nce

time

due

to

inte

rmitt

ent

or

cont

inuo

us s

hort

ci

rcui

ting

• Mic

robi

olog

ical

con

tam

inat

ion

-

due

to

less

con

tact

tim

e fo

r di

sinf

ectio

n• A

lgal

blo

oms

and

cyan

obac

teri

a to

xins

• Tur

bidi

ty -

due

to le

ss s

ettli

ng t

ime

• Tas

te a

nd o

dour

com

poun

ds -

fr

om fl

uctu

atin

g ch

lori

ne r

esid

ual

• Dep

ends

gre

atly

on

sedi

men

t lo

ad a

nd

vari

abili

ty in

qua

lity

of s

ourc

e w

ater

, whi

ch in

tu

rn is

dep

ende

nt o

n up

stre

am W

TP

/ sou

rce

man

agem

ent.

• Vol

ume

to infl o

w r

atio

• Bal

ance

bet

wee

n m

aint

aini

ng lo

w v

eloc

ities

w

hich

opt

imis

e se

ttlin

g of

sed

imen

t an

d in

erts

(eg

. fro

m li

me)

and

hig

h en

ough

to

mai

ntai

n ci

rcul

atio

n (t

ypic

ally

0.1

to

0.3

m/s

)• A

im fo

r w

ell m

ixed

tan

ks r

athe

r th

an p

lug

fl ow

reg

ime

and

allo

w fo

r th

is in

con

tact

tim

e ca

lcul

atio

n

• Des

ign

of t

ank

to fi

ll at

to

p an

d em

pty

at b

otto

m

(sep

arat

e in

let

/ out

let)

• Per

iodi

c is

olat

ion

and

spot

di

sinf

ectio

n of

tan

ks t

hat

have

thi

s pr

oble

m• M

onito

ring

of d

isin

fect

ion

resi

dual

and

/or

mic

robe

s at

tan

k ou

tlet

• Ope

ratio

n of

tan

k to

forc

e re

gula

r m

ixin

g an

d tu

rn-

over

• Ins

tall

baffl

es in

tan

k• S

mal

l circ

ulat

ion

jets

off

high

pre

ssur

e in

let

pipe

, w

ithin

larg

e ta

nks

to

mai

ntai

n ci

rcul

atio

n

• Rev

iew

tan

k de

sign

and

exp

ecte

d re

side

nce

time,

with

pa

rtic

ular

con

side

ratio

n to

sho

rt c

ircui

ting

• Red

esig

n in

let

/ out

let

or in

stal

l baffl e

s to

ens

ure

adeq

uate

co

ntac

t tim

e fo

r di

sinf

ectio

n w

here

req

uire

d, w

hich

is c

ritic

al

for

cont

rolli

ng m

icro

biol

ogic

al r

isk

• Avo

id s

cour

vel

ociti

es w

hich

re-

susp

end

colle

ctin

g se

dim

ents

. C

onsi

der

havi

ng in

lets

and

out

lets

off

the fl o

or.

• Run

at

low

leve

ls w

hen

dem

and

is lo

w, a

nd o

rien

t in

let

and

outle

t to

mai

ntai

n ci

rcul

atio

n• I

nsta

ll hi

gh v

eloc

ity je

t ty

pe in

let

to e

ntra

in a

nd m

ix.

• Pro

vide

sep

arat

e in

let

and

outle

t ar

rang

emen

t w

ith m

axim

um

sepa

ratio

n• A

dopt

mul

tiple

tan

ks w

here

dem

and

rang

e is

larg

e an

d se

ason

al (

ie. t

ake

tank

s ou

t of

ser

vice

in w

inte

r)• R

un m

ultip

le t

anks

in s

erie

s (n

ot p

aral

lel)

to a

void

sho

rt

circ

uitin

g• M

aint

ain

unifo

rm fl

ow r

ate

into

tan

k an

d pe

rmit

redu

ced

dept

h op

erat

ion

unde

r lo

w fl

ow d

eman

d


58

No

te:

(1)

Goo

d in

dust

rial

pra

ctic

e su

gges

ts t

hat

tank

s w

ith u

nfi lt

ered

sou

rce

wat

er s

houl

d be

cle

aned

eve

ry o

ne t

o th

ree

year

s, an

d fi l

tere

d su

pply

tan

ks e

very

thr

ee t

o fi v

e ye

ars.

Oth

er

rela

ted

Fac

t S

he

ets

:•

Fact

She

ets

25-2

6, 2

8 re

latin

g to

Con

tam

inat

ion

of S

ervi

ce R

eser

voir

s an

d Ta

nks

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

der

in a

sses

sin

g lik

elih

oo

d a

nd

sev

erit

y T

ypic

al P

reve

nti

ve

Mea

sure

sS

ugg

esti

on

s fo

r C

on

sid

erat

ion

Che

mic

al

cont

amin

atio

n fr

om in

corr

ect

chem

ical

dos

ing

at t

anks

eg.

duri

ng s

pot

disi

nfec

tion

• Tas

te a

nd o

dour

com

poun

ds

- fr

om a

dditi

onal

dis

infe

ctan

t, bl

endi

ng c

hlor

ine

/ chl

oram

ine

and

slim

e / d

isin

fect

ant

reac

tions

• Tur

bidi

ty -

from

slim

e de

tach

men

t• C

hem

ical

con

tam

inat

ion

- if

wro

ng c

hem

ical

use

d; d

isin

fect

ion

bypr

oduc

ts (

incr

ease

d)

• Hig

hest

ris

k fr

om u

se o

f poo

rly

trai

ned

peop

le o

n an

irre

gula

r ba

sis.

• Lev

el o

f sup

ervi

sion

and

ver

ifi ca

tion

(cro

ss-

chec

ks)

prio

r to

add

ition

of c

hem

ical

s im

port

ant.

• Deg

ree

of m

ixin

g in

the

tan

k pr

ior

to o

utle

t• D

egre

e of

ble

ndin

g do

wns

trea

m w

ith w

ater

s co

ntai

ning

a d

iffer

ent

disi

nfec

tant

• Doc

umen

ted

oper

atin

g pr

oced

ures

• Ope

rato

r tr

aini

ng• I

nspe

ctio

ns b

y su

perv

isor

s• I

sola

tion

of t

ank

if re

quire

d an

d po

ssib

le

• Onl

y us

e ap

prop

riat

ely

trai

ned

pers

onne

l for

the

tas

k of

ad

ding

che

mic

als

to p

otab

le w

ater

sup

plie

s• E

nsur

e cl

ear

inst

ruct

ions

and

ope

ratio

nal p

roce

dure

s gi

ven

on

the

type

and

qua

ntity

of c

hem

ical

to

be u

sed

• Dev

elop

a d

ocum

enta

tion

syst

em fo

r th

is a

ctiv

ity w

hich

in

volv

es s

ever

al v

erifi

catio

n po

ints

, esp

ecia

lly fo

r ca

lcul

atio

ns

of q

uant

ities

req

uire

d• E

stab

lish

degr

ee o

f sho

rt c

ircui

ting

likel

y in

tan

k an

d ad

just

do

sing

pro

cess

acc

ordi

ngly


59

28

. Ex

tern

al C

on

tam

inat

ion

of

Se

rvic

e R

ese

rvo

irs

and

Tan

ks

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Acc

ess

by a

nim

als

- in

clud

ing

bir

ds

thro

ugh

open

ings

in

fi xe

d co

vers

or

at o

pen

rese

rvoi

rs/

tank

s

• M

icro

biol

ogic

al

cont

amin

atio

n -

from

w

aste

and

dea

d an

imal

s •

Turb

idity

- fr

om s

tir-

up o

f tan

k se

dim

ents

• Ta

ste

and

odou

r co

mpo

unds

- al

gae

• C

olou

r

• Fr

eque

ncy

of d

etec

tion

of c

olifo

rms

or

plat

e co

unts

, esp

ecia

lly fa

ecal

col

iform

s or

nec

rotic

bac

teri

a•

Num

ber

of a

nim

als

/ ske

leto

ns fo

und

in

tank

s du

ring

pas

t in

spec

tions

• Le

vel o

f dis

infe

ctio

n re

sidu

al•

Freq

uenc

y of

spo

t do

sing

of c

hlor

ine

in r

espo

nse

to u

nusu

al o

dour

in z

one

supp

lied

from

tan

k•

Exte

nt o

f sou

rce

wat

er s

cree

ning

fo

r ex

clus

ion

of fi

sh a

nd a

nim

als

(eg.

zoop

lank

ton,

wat

er fl

eas)

• N

utri

ent

cont

ent

of w

ater

• R

emai

ns o

f nes

ts, b

ird

drop

ping

s on

w

alls

and

roo

f sup

port

str

uctu

res

• Lo

catio

n an

d nu

mbe

r of

hol

es in

any

co

vers

and

at

roof

/ w

all j

unct

ions

• Sc

reen

s (2

-3m

m a

pert

ure

size

) on

air

ven

ts•

Ensu

re c

hlor

ine

resi

dual

• C

over

tan

ks•

Vert

ical

ove

rfl o

w p

ipe

with

gr

ill•

Take

offl

ine

and

add

algi

cide

or

spo

t ch

lori

nato

r•

Scre

en (

5-10

mm

) at

re

serv

oir/

tank

out

let

• M

onito

r al

gae

leve

ls in

ope

n tr

eate

d w

ater

sto

rage

s

• R

evie

w e

xper

ienc

e re

latin

g to

acc

ess

by a

nim

als

and

bird

s•

Und

erta

ke r

egul

ar in

spec

tion

of c

over

and

mes

h / g

rills

, as

part

of

regu

lar

tank

insp

ectio

ns/m

aint

enan

ce•

Prio

r to

cle

anin

g, in

spec

t fl o

or /

wal

ls fo

r si

gns

of a

nim

al e

ntry

Acc

ess

by h

uman

s, in

clud

ing

vand

alis

m,

sabo

tage

• M

icro

biol

ogic

al

cont

amin

atio

n -

from

lit

ter

and

was

te

• C

hem

ical

co

ntam

inat

ion

- fr

om

haza

rdou

s su

bsta

nces

• Tu

rbid

ity

• N

umbe

r of

rec

orde

d br

eak-

ins

(from

se

curi

ty in

spec

tion

repo

rts)

• In

dica

tion

of r

isk

with

bre

ak-in

(eg

ab

ando

ned

chem

ical

con

tain

ers)

• R

isk

can

incl

ude

acce

ss fo

r sa

mpl

ing

– su

gges

t in

stal

latio

n of

sam

plin

g ta

p on

ou

tsid

e of

tan

k•

Num

ber

of r

epor

ts o

f evi

denc

e of

br

eak-

in t

o si

te

• U

se o

f loc

ked

peri

met

er

fenc

es•

Lock

ed a

cces

s to

wer

s an

d la

dder

s•

Lock

ed h

atch

es o

n ta

nks

• C

hlor

ine

resi

dual

• In

cide

nt a

nd e

mer

genc

y m

anag

emen

t pr

otoc

ol t

o ra

pidl

y is

olat

e, in

spec

t an

d te

st w

ater

at

tank

if

unau

thor

ised

acc

ess

dete

cted

• R

egul

ar s

ite in

spec

tion

for

sign

s of

una

utho

rise

d ac

cess

• R

evie

w e

xper

ienc

e re

latin

g to

acc

ess

by h

uman

s•

Ensu

re lo

ckin

g ar

rang

emen

ts o

n ac

cess

tow

ers

and

hatc

hes.

Con

side

r in

crea

sing

sec

urity

, whi

ch c

ould

incl

ude

doub

le lo

cks

and

alar

ms,

at h

igh

risk

site

s (b

ased

on

hist

ory

or b

reak

-ins)

• C

onsi

der

inst

alla

tion

of c

yclo

ne fe

ncin

g ar

ound

tan

k•

Inst

all s

ampl

e ta

p on

out

let

pipe

of t

ank

• In

stal

l a p

ositi

on s

witc

h on

hat

ch t

o re

mot

ely

reco

rd a

cces

s•

Enco

urag

e lo

cal c

omm

unity

rep

ortin

g

Ingr

ess

of a

nim

als

and

leaf

litt

er v

ia

roof

dra

inag

e an

d ai

r ve

nts

• M

icro

biol

ogic

al

cont

amin

atio

n -

from

an

imal

dro

ppin

gs,

rott

ing

vege

tatio

n •

Turb

idity

• N

atur

al o

rgan

ic

mat

ter

- eg

leaf

litt

er•

Che

mic

al

cont

amin

atio

n -

lead

, or

gani

c ch

emic

als,

pest

icid

e / h

erbi

cide

sp

ray

drift

• Pr

imar

y ri

sk is

from

mic

robe

s ar

isin

g fr

om a

nim

al d

ropp

ings

and

leav

es e

tc•

Pote

ntia

l for

che

mic

al fa

ll-ou

t ie

ha

zard

ous

dust

s fr

om n

earb

y in

dust

ry,

inte

nsiv

e ch

icke

n sh

eds

or m

ajor

ro

adw

ays

• D

esig

n of

dra

inag

e to

avo

id

gutt

er o

verfl

ow

into

tan

k an

d po

ndin

g on

roo

f (eg

slo

ped

roof

) an

d lip

s at

hat

ches

• R

estr

ictio

n of

hum

an a

cces

s to

roo

f top

(eg

for

park

ing)

–

redu

ce p

ossi

bilit

y of

che

mic

al

cont

amin

atio

n (fu

els

/ oils

)•

Tim

ely

repa

ir o

f joi

nt le

aks

• R

egul

ar in

spec

tions

(an

nual

ly)

of r

oof a

nd d

rain

con

ditio

n•

All

air

vent

s to

hav

e co

vers

and

suffi c

ient

are

a to

avo

id h

igh

air

infl o

w r

ates

• N

o ce

ntre

sto

rmw

ater

cha

nnel

s


60

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Acc

ess

by a

nim

als-

from

ups

trea

m

sour

ce

eg a

nim

als

trap

ped

and

dest

roye

d by

act

ion

of in

let

cont

rol v

alve

s on

ta

nks

• Mic

robi

olog

ical

co

ntam

inat

ion

- fr

om

dead

ani

mal

s • T

aste

and

odo

ur

com

poun

ds

• Tur

bidi

ty

• If

upst

ream

sou

rce

is n

ot fi

ltere

d or

scr

eene

d an

d ha

s hi

gh p

ress

ure

redu

cing

val

ves

at in

let

to t

ank,

ani

mal

s m

ay b

e fr

agm

ente

d an

d pa

ss t

hrou

gh

• Is

offt

ake

upst

ream

an

aque

duct

-

anim

als

drow

n be

caus

e th

ey c

anno

t ge

t ou

t

• Sc

reen

s on

out

let

of u

pstr

eam

so

urce

• Fi

ltrat

ion

upst

ream

• R

egul

ar in

spec

tion

of s

cree

ns

at a

qued

uct

/ pip

e in

let

poin

ts

• Sc

reen

out

let

of e

ach

trea

ted

wat

er r

eser

voir

/tan

k (5

-10

mm

ape

rtur

e si

ze)

• R

evie

w e

xper

ienc

e re

latin

g to

ani

mal

ingr

ess

• U

nder

take

reg

ular

insp

ectio

n of

ups

trea

m s

cree

ns a

t ri

ver

/ aq

uedu

ct o

fftak

e

• En

sure

scr

eens

on

outle

ts o

f ups

trea

m s

ourc

es (

eg r

iver

, res

ervo

ir)

that

are

not

tre

ated

• M

onito

r ch

lori

ne r

esid

ual a

nd m

icro

bes

at h

igh

risk

tan

k ou

tlet

wee

kly.

• D

esig

n aq

uedu

ct w

alls

so

that

ani

mal

s ca

n ge

t ou

t if

they

fall

in

Acc

ess

by a

nim

als-

thro

ugh

overfl o

w

drai

n

• Mic

robi

olog

ical

co

ntam

inat

ion

- fr

om

dead

ani

mal

s

• Tas

te a

nd o

dour

co

mpo

unds

• O

verfl

ow

dra

ins

at g

roun

d le

vel a

re

easi

ly a

cces

sibl

e by

ani

mal

s•

Inst

all s

cree

n on

end

of d

rain

• In

stal

l a v

ertic

al s

ectio

n of

pi

pe o

n ov

erfl o

w d

rain

to

prev

ent

anim

als

gett

ing

into

th

e ta

nk

• R

evie

w e

xper

ienc

e re

latin

g to

ani

mal

ingr

ess

• En

sure

ver

tical

sec

tion

pres

ent

on o

verfl

ow

pip

e

• In

spec

t in

tegr

ity o

f mes

h du

ring

reg

ular

insp

ectio

ns

• C

heck

for

sign

s of

bir

ds e

tc. d

urin

g re

gula

r in

spec

tions

Ingr

ess

of

cont

amin

ated

gr

ound

wat

er

• Mic

robi

olog

ical

co

ntam

inat

ion

- fr

om

dead

ani

mal

s

• Tas

te a

nd o

dour

co

mpo

unds

• Che

mic

al

cont

amin

atio

n

• C

an g

et in

gres

s of

gro

undw

ater

from

ex

pans

ion

/ con

trac

tion

of c

oncr

ete

tank

s du

ring

dra

w / fi l

l

• St

orag

e of

haz

ardo

us c

hem

ical

s ab

ove

tank

• M

icro

biol

ogic

al c

onta

min

atio

n ca

n co

me

from

soi

l, le

akin

g se

wer

s, se

ptic

ta

nk e

ffl ue

nt, e

ffl ue

nt r

e-us

e, e

tc

• G

roun

dwat

er in

are

a co

uld

be

cont

amin

ated

by

haza

rdou

s ch

emic

als

(eg

from

indu

stri

al s

pills

, lea

ks)

• D

egre

e of

sho

rt c

ircu

iting

, dra

w a

nd fi

ll, an

d de

tent

ion

time

• R

egul

ar d

ewat

erin

g an

d in

spec

tion

of t

ank

for

leak

age

espe

cial

ly in

wet

per

iods

• M

aint

enan

ce a

nd t

imel

y re

pair

of

leak

s

• M

aint

ain

high

wat

er le

vel i

n ta

nk t

o m

aint

ain

outw

ard

pres

sure

• C

ondu

ct r

egul

ar in

spec

tions

(ev

ery

2 –

5 ye

ars

depe

ndin

g on

the

ag

e of

the

tan

k an

d th

e ri

sk fr

om it

s lo

catio

n)

• M

onito

r lo

cal g

roun

d w

ater

qua

lity

and

leve

ls

• D

esig

n ta

nk w

ith a

n ex

tern

al g

roun

dwat

er d

rain

age

syst

em w

ith

insp

ectio

n pi

t

• D

o no

t pe

rmit

stor

age

of a

ny h

azar

dous

che

mic

als

in a

rea

abov

e ta

nk

Oth

er

rela

ted

Fac

t S

he

ets

:•

Fact

She

ets

25-2

7 re

latin

g to

Con

tam

inat

ion

of S

ervi

ce R

eser

voir

s an

d Ta

nks


61

29

. Pip

eli

ne

Re

pai

rs a

nd

Mai

nte

nan

ceS

ou

rce

of

Haz

ard

/Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

tyT

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Ingr

ess

of

cont

amin

ants

by

backfl o

w t

hrou

gh:

• pi

pe jo

ints

• ai

r va

lves

• pe

rfor

atio

ns

• le

akin

g va

lves

and

hy

dran

ts;

Ingr

ess

caus

ed b

y lo

ss o

f pre

ssur

e in

m

ain

duri

ng:

• pi

pe b

urst

• pi

pe r

epai

rs

• ve

ry h

igh fl o

ws

(eg.

fi refi

ght

ing)

• M

icro

biol

ogic

al

cont

amin

atio

n -

from

le

akin

g se

wer

s, se

ptic

ta

nk d

rain

age,

effl

uent

re

-use

see

page

•

Turb

idity

- f

rom

soi

l

• Po

tent

ial f

or c

hem

ical

co

ntam

inat

ion

-

in

clud

ing

heav

y m

etal

s an

d pe

troc

hem

ical

s (le

acha

te fr

om

cont

amin

ated

soi

l, gr

ound

wat

er o

r effl u

ent

re-u

se)

• Ta

ste

and

odou

r co

mpo

unds

• Lo

catio

n of

freq

uent

ly b

urst

are

as

– ar

e th

ey in

low

pre

ssur

e ar

eas

(eg

hills

, ext

rem

ities

of s

yste

m, a

ir v

alve

s, hy

dran

ts)?

• A

bilit

y to

isol

ate

area

. Thi

s in

clud

es

isol

atio

n of

con

sum

ers

in b

urst

are

a

• A

bilit

y to

fully

fl us

h ar

eas

of p

ossi

ble

cont

amin

atio

n af

ter

repa

ir (

is fl

ow

dire

ctio

n kn

own,

are

all

offt

akes

fl u

shed

?)

• Fl

owra

te fo

r fl u

shin

g an

d w

heth

er it

is

suffi

cien

t to

rem

ove

cont

amin

atio

n?

• W

ork

crew

pra

ctic

es a

nd w

heth

er t

hese

w

ill a

void

con

tam

inat

ion

• U

rgen

cy o

f rep

air

and

whe

ther

thi

s le

ads

to p

robl

ems

• Te

mpo

rary

sup

ply

used

whi

ch is

not

cl

ean

(See

nex

t pa

ge)

• M

inim

um p

ress

ures

and

allo

wan

ce fo

r fi r

e fi g

htin

g de

man

ds

• H

isto

rica

l inc

iden

ts w

here

bac

kfl o

w h

as

been

det

ecte

d

• Is

olat

ion

of m

inim

um p

ipel

ine

leng

th a

roun

d bu

rst

poin

t

• R

epai

rs u

nder

pre

ssur

e w

ithou

t ne

ed t

o em

pty

mai

n

• R

epai

r pr

actic

es -

dis

infe

ctio

n of

eq

uipm

ent

• W

ater

cre

ws

and

equi

pmen

t se

para

te fr

om s

ewer

age

crew

s

• Fl

ushi

ng o

f affe

cted

pip

es

• D

isin

fect

ion

of a

ffect

ed p

ipes

(t

ypic

ally

onl

y un

dert

aken

for

new

w

orks

)

• A

ppro

ved

and

appr

opri

ate

mat

eria

ls s

elec

tion

• Pr

esen

ce o

f dis

infe

ctio

n re

sidu

al in

di

stri

butio

n sy

stem

• Pl

acem

ent

of n

ew m

ains

aw

ay

from

hig

h ri

sk a

reas

whe

re

poss

ible

• M

aint

ain

min

imum

pre

ssur

e at

hig

h po

ints

• Sp

ring

load

ed h

ydra

nt b

all

• In

sect

scr

eens

at

air

valv

es

• Le

ak d

etec

tion

and

prev

entio

n

• En

forc

e pl

umbi

ng s

tand

ard

(air

ga

ps /

doub

le n

on r

etur

n va

lves

)

• C

onfi r

m a

bsen

ce o

f con

tam

inan

ts b

y un

dert

akin

g so

me

chec

k sa

mpl

es, e

g ba

cter

iolo

gica

l sam

ples

with

in v

icin

ity o

f bur

st p

ipe

with

in a

few

hou

rs o

f mai

n be

ing

brou

ght

back

on

line1

• M

aint

enan

ce o

f rel

ativ

ely

high

pre

ssur

es in

pip

es is

cri

tical

, es

peci

ally

on

high

poi

nts

(>15

m)

• U

nder

take

uni

dire

ctio

nal fl

ush

, fro

m c

lean

to

dirt

y en

d, a

t ve

loci

ty o

f >1

m/s

to

ensu

re r

emov

al o

f sed

imen

t / s

limes

. Sh

ould

fl us

h un

til w

ater

vis

ibly

cle

an a

nd n

o ai

r. Ef

fect

ive

fl ush

ing

afte

r re

pair

is c

ritic

al

• En

sure

the

re is

tra

inin

g an

d aw

aren

ess

of h

ow t

o m

inim

ise

the

size

of i

sola

ted

area

s of

pip

e ne

twor

k w

hen

dew

ater

ing

to

repa

ir b

urst

• D

isin

fect

mai

ns a

fter

bur

sts

-eg

10 m

g/L

for

½ h

r2

• Li

st a

nd u

se a

ppro

ved

mat

eria

ls fo

r re

pair

of w

ater

mai

ns

• C

ap a

ny o

peni

ng le

ft o

vern

ight

to

ensu

re a

nim

als

are

kept

out

• D

evel

op a

ppro

pria

te p

roce

dure

s in

clud

ing

chec

klis

t to

be

com

plet

ed (

area

isol

ated

indi

catin

g w

hich

val

ves

clos

ed a

nd in

w

hat

orde

r, lo

catio

n of

bur

st, d

ewat

erin

g of

hol

e ar

ound

bur

st,

time

take

n fo

r re

pair,

che

ck t

hat fi t

tings

/ eq

uipm

ent

disi

nfec

ted,

fl u

shin

g pr

oced

ure

unde

rtak

en &

res

ults

, ord

er o

f val

ves

open

ed t

o br

ing

back

on-

line)

• U

se a

dequ

atel

y tr

aine

d cr

ew, w

ith p

eopl

e an

d eq

uipm

ent

dedi

cate

d to

pot

able

wat

er

• In

stal

l new

wat

er m

ains

at

leas

t 3

m fr

om s

ewer

s, an

d pr

efer

ably

abo

ve s

ewer

s3

• M

aint

ain

up-t

o-da

te p

lans

of p

ipe

loca

tions

for

supp

ly t

o 3r

d pa

rtie

s un

dert

akin

g ex

cava

tion

wor

k, t

o he

lp p

reve

nt d

amag

e to

wat

er m

ains

, and

to

min

imis

e th

e se

ctio

n of

pip

e ne

twor

k w

ith n

o pr

essu

re d

urin

g re

pair

s


62

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Scou

r ca

used

by

abno

rmal

fl ow

(hi

gh

fl ow

, fl o

w r

ever

sal)

from

bur

st m

ain

• Mic

robi

olog

ical

co

ntam

inat

ion

• C

hem

ical

co

ntam

inat

ion

-

alum

iniu

m, m

anga

nese

, ir

on

• Tur

bidi

ty

• Ex

tent

of p

ipe

netw

ork

affe

cted

(on

ly

isol

ated

sm

all p

ipe

vers

us la

rge

tran

sfer

m

ain)

• Sl

ime

type

s an

d th

ickn

ess

know

n to

be

pres

ent

in p

ipes

• Se

dim

ent

build

up

know

n to

be

pres

ent

in p

ipes

• Ve

loci

ties

whi

ch g

ive

rise

to

rele

ase

of

slim

es•

Are

as w

here

mod

ellin

g in

dica

tes

reve

rse fl o

ws

or p

eak

velo

city

> 1

m/s

• O

pera

tiona

l pro

cedu

res

for

isol

atin

g an

d re

inst

atin

g bu

rst

mai

ns –

eg

clos

ing

valv

es s

low

ly

and

in c

orre

ct o

rder

• O

pera

te t

o m

inim

ise

sudd

en

pres

sure

incr

ease

(eg

. wat

er

ham

mer

), hi

gh v

eloc

ity o

r fl o

w

reve

rsal

, par

ticul

arly

in la

rge

mai

ns•

Min

imis

e m

anga

nese

/ so

lubl

e ir

on

/ sus

pend

ed s

edim

ents

in s

ourc

e w

ater

• R

egul

ar c

lean

ing

of p

ipe

netw

ork

to a

void

sed

imen

t /

slim

e bu

ild

up•

Rep

laci

ng o

ld p

ipes

with

hig

h lik

elih

ood

of b

urst

s

• En

sure

any

hyd

raul

ic t

ests

of p

ipe

netw

ork

are

prec

eded

by

notifi

cat

ion

of w

ater

qua

lity

offi c

ers

• A

ssig

n ad

equa

tely

tra

ined

per

son

to o

pera

te n

etw

ork

duri

ng

repa

irs

• U

nder

take

reg

ular

pip

e cl

eani

ng t

o m

inim

ise

slim

e an

d se

dim

ent

build

up

• Fo

cus

on a

reas

with

fl ow

rev

ersa

l and

hig

h pe

ak v

eloc

ity fo

r cl

eani

ng in

spr

ing

• D

evel

op a

utom

ated

exp

ert

oper

atio

nal s

yste

ms

base

d on

m

ulti-

poin

t (fl

ow p

ress

ure)

man

agem

ent

to m

inim

ise

high

fl ow

, re

vers

e fl o

w, a

nd p

ress

ure

surg

es

Tem

pora

ry s

uppl

y ar

rang

emen

t (d

urin

g bu

rst

repa

ir)

• Mic

robi

olog

ical

co

ntam

inat

ion

– cr

oss

conn

ectio

ns t

o re

use

pipe

• Tur

bidi

ty• T

aste

and

odo

ur

com

poun

ds• C

olou

r

• A

vaila

bilit

y of

alte

rnat

ive

good

sup

ply

poin

t fr

om n

etw

ork

• Im

pact

on

netw

ork

• D

urat

ion

and

size

of a

rea

affe

cted

• C

ontr

act

with

bot

tled

wat

er a

nd/o

r ta

nker

sup

plie

r re

gard

ing

wat

er q

ualit

y•

Ass

ign

a di

ffere

nt p

ipe

colo

ur fo

r re

use

syst

em

• O

pera

tiona

l pro

cedu

res

to

fl ush

/ di

sinf

ect

tem

pora

ry p

ipe

conn

ectio

n•

Qua

lity

cont

rol f

or b

ottle

d w

ater

an

d ta

nker

s

• D

evel

op a

ppro

pria

te p

roto

cols

and

ope

ratio

nal p

roce

dure

s fo

r cl

eani

ng a

nd d

isin

fect

ing

alte

rnat

e su

pply

equ

ipm

ent

• Pe

riod

ic a

udits

• Pu

t in

pla

ce w

ater

qua

lity

requ

irem

ents

(eg

tan

kers

to

carr

y po

tabl

e w

ater

onl

y, bo

ttle

d w

ater

, qua

lity

crite

ria

and

test

ing)

, an

d /o

r ha

ve p

roce

dure

s in

pla

ce t

o en

sure

it is

tho

roug

hly

clea

ned

and

disi

nfec

ted

• En

sure

reu

se s

yste

m c

ross

con

nect

ions

ris

k is

car

eful

ly

thou

ght

thro

ugh

to m

inim

ise

its li

kelih

ood

• En

sure

con

trac

tors

and

cre

ws

unde

rsta

nd w

ater

qua

lity

issu

esA

ltern

ate

wat

er

supp

ly d

urin

g bu

rst

repa

ir

• Mic

robi

olog

ical

co

ntam

inat

ion

• Tur

bidi

ty

• C

olou

r • C

yano

bact

eria

tox

ins

- e

g if

sour

ced

from

re

serv

oir

pron

e to

al

gae

• Tas

te a

nd o

dour

co

mpo

unds

- c

hlor

ine

to c

hlor

amin

e, lo

w t

o hi

gh t

otal

dis

solv

ed

solid

s

• C

hang

ed w

ater

qua

lity

asso

ciat

ed w

ith

alte

rnat

ive

supp

ly•

If ch

ange

in w

ater

qua

lity

is a

maj

or

conc

ern

to in

dust

ry, s

ever

ity w

ill

depe

nd o

n m

anag

emen

t of

pub

lic

rela

tions

• Se

lect

ion

of a

ltern

ate

sour

ce•

Ass

ign

a su

itabl

e em

erge

ncy

sour

ce o

f sup

ply

• Pr

epar

e fo

r m

anag

emen

t of

any

res

tric

tions

(in

clud

ing

rest

rict

ions

on

use

of w

ater

bec

ause

of q

ualit

y)•

App

ropr

iate

pro

cedu

res

for

notifi

cat

ion


63

So

urc

e o

f H

azar

d/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Ingr

ess

of

cont

amin

ants

dur

ing

mai

ns t

appi

ng

proc

ess

• Mic

robi

al

cont

amin

atio

n -fr

om

wat

er in

wor

k tr

ench

or

insu

ffi ci

ent

seal

ing

of t

appi

ng o

nce

inst

alle

d, c

onst

ruct

ion

mat

eria

ls

• Tur

bidi

ty

• Che

mic

al

cont

amin

atio

n -

from

mat

eria

ls o

f co

nstr

uctio

n (e

g pH

, co

pper

, pla

stic

sha

ving

s, ot

hers

)

• W

heth

er t

appi

ng is

to

be p

erfo

rmed

w

ith t

he m

ain

offl i

ne (

no p

ress

ure)

an

d in

a h

igh

risk

are

a un

der

wet

w

eath

er c

ondi

tions

(eg

hig

h po

tent

ial

for

mic

robi

al c

onta

min

atio

n fr

om

soil/

man

ure,

leak

ing

sew

ers,

sept

ic t

ank

seep

age,

effl

uent

re-

use)

• A

bilit

y to

isol

ate

shor

t le

ngth

s of

pip

e,

abili

ty t

o fu

lly fl

ush

pipe

of p

ossi

ble

cont

amin

atio

n af

ter

inst

alla

tion

(is fl

ow

dire

ctio

n kn

own,

can

all

offt

akes

be

fl ush

ed?)

• W

ork

crew

pra

ctic

es –

suffi c

ient

tr

aini

ng a

nd u

nder

stan

ding

of w

ater

qu

ality

issu

es

• Fl

ushi

ng fl

owra

te s

uffi c

ient

to

rem

ove

cont

amin

atio

n (>

1.0m

/s)

• Ta

ppin

gs b

y ot

her

part

ies

(eg

deve

lope

rs)

– do

es w

ater

sup

ply

owne

r ha

ve a

ny c

ontr

ol o

ver

thei

r pr

actic

es?

• C

lean

ing

and

disi

nfec

tion

of a

ll fi x

ture

s an

d eq

uipm

ent

• Is

olat

ion

of a

rea

bein

g ta

pped

• D

rain

age

of w

ork

tren

ch p

rior

to

tapp

ing

into

wat

er m

ain

• U

se o

f de

dica

ted

crew

s an

d eq

uipm

ent

for

wat

er s

uppl

y

• Fl

ushi

ng a

nd d

isin

fect

ion

of m

ains

• U

se o

f app

rove

d m

ater

ials

for

pota

ble

wat

er s

uppl

y

• Pr

esen

ce o

f dis

infe

ctio

n re

sidu

al

in d

istr

ibut

ion

syst

em

• C

ompl

ete

tapp

ing

unde

r pr

essu

re

• D

evel

op a

ppro

pria

te p

roce

dure

s an

d en

sure

the

y ar

e fo

llow

ed

by t

he w

ater

sup

ply

owne

r an

d de

velo

pers

• En

sure

cle

anin

g an

d di

sinf

ectio

n of

new

fi tt

ings

just

pri

or t

o in

stal

latio

n

• C

ompl

ete

tapp

ing

with

mai

n un

der

pres

sure

(bu

t no

t in

se

rvic

e) w

here

ver

poss

ible

• M

inim

ise

leng

th o

f pip

e su

bjec

t to

effe

ct o

f tap

ping

, and

fl us

h m

ain

bein

g ta

pped

whe

reve

r po

ssib

le

No

tes:

(1)

Bact

erio

logi

cal s

ampl

ing

(at

leas

t E.

coli

and

chlo

rine

res

idua

l) is

str

ongl

y re

com

men

ded:

• af

ter

each

bur

st r

epai

r w

ithin

2 h

rs o

f rep

air

com

plet

ion,

and

;

• du

ring

com

mis

sion

ing

of n

ew m

ains

(af

ter

supe

rchl

orin

ated

wat

er is

fl us

hed

out

and

mai

n refi l

led

with

nor

mal

mai

ns w

ater

and

bef

ore

it is

put

bac

k in

to s

ervi

ce);

Thi

s pr

ovid

es e

vide

nce

of t

he e

ffect

iven

ess

of t

he p

roce

dure

s em

ploy

ed a

nd t

he s

afet

y of

the

wat

er s

uppl

y. A

s a

min

imum

, sam

ples

sho

uld

be c

olle

cted

on

a re

gula

r ba

sis

as v

erifi

catio

n th

at t

he

fl ush

ing

proc

edur

e is

effe

ctiv

e. S

ee A

WW

A S

tand

ard

for

Dis

infe

ctin

g Wat

er M

ains

and

Aus

tral

ian

Wat

er In

dust

ry T

echn

ical

Sta

ndar

d fo

r C

hlor

inat

ion

of W

ater

Mai

ns.

(2)

Dis

infe

ctio

n pr

actic

es fo

r m

ains

bur

sts

vary

wid

ely.

AW

WA

Sta

ndar

d re

quir

es d

isin

fect

ion

whe

re p

ossi

ble

with

up

to 3

00 m

g/L

chlo

rine

sol

utio

n fo

r 15

min

s, th

e A

ustr

alia

n W

ater

Indu

stry

St

anda

rd a

ssum

es 1

0 m

g/L,

whe

reas

man

y w

ater

aut

hori

ties

do n

ot d

isin

fect

aft

er b

urst

s at

all

due

to d

iffi c

ulty

in d

ispo

sing

of h

ighl

y ch

lori

nate

d w

ater

and

pre

ssur

e to

get

the

rep

air

team

to

mov

e on

to

the

next

bur

st. W

hile

fl us

hing

red

uces

the

ris

k fr

om in

gres

s of

con

tam

inan

ts, d

isin

fect

ion

wou

ld p

rovi

de a

n ad

ditio

nal s

afeg

uard

aga

inst

mic

robi

al c

onta

min

atio

n. T

he c

once

ntra

tion

and

dete

ntio

n tim

e ha

s be

en d

evel

oped

to

mee

t th

e co

ntac

t tim

e re

quir

emen

ts fo

r in

activ

atio

n of

Gia

rdia

cys

ts, a

nd is

con

side

red

to b

e a

reas

onab

le, p

ract

ical

leve

l.

(3)

Typi

cal e

ngin

eeri

ng s

tand

ard.

LeC

heva

llier

, M. C

halle

nges

to

Mai

ntai

ning

and

Impr

ovin

g M

icro

bial

Wat

er Q

ualit

y, W

ater

TEC

H c

onfe

renc

e, A

dela

ide,

200

0.

Re

fere

nce

s:•

AW

WA

Sta

ndar

d fo

r D

isin

fect

ing W

ater

Mai

ns, A

NSI

/AW

WA

C65

1-92

.•

Wat

er In

dust

ry T

echn

ical

Sta

ndar

ds, C

hlor

inat

ion

of W

ater

Mai

ns, 9

5-09

2.1.

• W

ater

Ret

icul

atio

n D

isin

fect

ion

Cod

e of

Pra

ctic

e, M

anuk

au W

ater

, 199

8.


64

30

. Cle

anin

g o

f M

ain

sS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

ass

ess

ing

lik

eli

ho

od

an

d s

eve

rity

T

ypic

al P

reve

nti

ve M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Cle

anin

g of

mai

ns

incl

udin

g:•

exce

ssiv

e oi

l in

air

used

in

air

sco

urin

g•

ingr

ess

of c

onta

min

ated

gr

ound

wat

er d

ue t

o lo

calis

ed lo

w p

ress

ures

an

d pr

essu

re t

rans

ient

s•

inef

fect

ive

bloc

k fl u

shin

g, st

irri

ng u

p se

dim

ents

bu

t no

t re

mov

ing

them

at

fl us

h po

int

• in

adeq

uate

isol

atio

n or

ad

vice

to

cust

omer

s re

gard

ing

tem

pora

ry

supp

ly d

isru

ptio

n (e

g. di

alys

is p

atie

nts)

• er

osio

n of

pip

e lin

ings

• M

icro

biol

ogic

al

cont

amin

atio

n

• C

hem

ical

co

ntam

inat

ion

- as

best

os fi

bres

, hy

droc

arbo

ns (

oil

from

air

sco

urin

g)•

Turb

idity

• Fr

eque

ncy

of c

lean

ing

• O

pera

tiona

l pro

cedu

res

docu

men

ted

and

follo

wed

• K

now

ledg

e of

sys

tem

• A

dequ

acy

of in

spec

tions

• Ef

fect

iven

ess

of c

lean

ing

• Se

nsiti

vity

of c

usto

mer

s (e

g. be

vera

ge

man

ufac

ture

rs, h

ospi

tals

, dia

lysi

s pa

tient

s)•

Pipe

mat

eria

ls, t

ype

and

age

• St

abili

ty a

nd c

orro

sivi

ty o

f wat

er•

Type

s an

d lo

catio

n of

cus

tom

er

com

plai

nts

and

avai

labl

e re

cord

s of

co

mpl

aint

s•

Kno

wle

dge

and

leve

l of m

onito

ring

of

wat

er q

ualit

y w

ithin

the

sys

tem

• O

ccur

renc

e of

col

iform

s•

Lega

l res

pons

ibili

ties

and

impa

cts

of

exis

ting

cust

omer

con

trac

ts

• A

ccur

ate

pipe

loca

tion,

age

and

m

ater

ial i

nfor

mat

ion

• C

orre

ct is

olat

ion

of a

rea

bein

g cl

eane

d (u

nidi

rect

iona

l)•

Cle

anin

g se

quen

ce (

from

cle

an e

nd

tow

ards

dir

ty e

nd)

• D

isin

fect

ion

of e

quip

men

t•

Reg

ular

cha

ngin

g of

air

com

pres

sor

oil fi

lter

• C

usto

mer

not

ifi ca

tion

and

educ

atio

n•

Trai

ning

of c

lean

ing

crew

s•

Use

of c

orre

ct e

quip

men

t•

Post

mon

itori

ng (

mic

robi

olog

ical

qu

ality

and

tur

bidi

ty)

• In

spec

tions

and

aud

iting

• Pa

intin

g of

wat

er m

eter

and

val

ves

whe

re d

ialy

sis

patie

nts

live

• R

ecor

ding

of m

ains

sec

tion

clea

ned

and

date

com

plet

ed

• R

evie

w h

isto

ry /

occu

rren

ces

/ com

posi

tion

of w

ater

co

mpl

aint

s re

ceiv

ed d

urin

g or

aft

er c

lean

ing

• D

evel

op o

vera

ll sy

stem

cle

anin

g st

rate

gy•

Rev

iew

and

aud

it cl

eani

ng p

roce

dure

s•

Ensu

re c

orre

ct s

elec

tion

of c

lean

ing

met

hods

and

eq

uipm

ent

• C

aref

ul c

usto

mer

not

ifi ca

tion

is e

ssen

tial

• En

sure

all

staf

f are

ade

quat

ely

trai

ned

• En

sure

sep

arat

e cl

eani

ng c

rew

s an

d eq

uipm

ent

exis

ts fo

r se

wag

e an

d w

ater

mai

ns•

Ana

lyse

sus

pend

ed s

olid

s to

det

erm

ine

wha

t is

bui

ldin

g up

in

the

pip

e•

Iden

tify

loca

tion

of s

ensi

tive

cust

omer

s by

col

our

codi

ng

wat

er m

eter

s an

d va

lves

Oth

er

rela

ted

Fac

t S

he

ets

: •

29. P

ipel

ine

Rep

airs

and

Mai

nten

ance

• 36

. Aqu

educ

ts


65

31

. Pip

e M

ate

rial

s, P

riva

te M

ain

s an

d C

ust

om

er

Plu

mb

ing

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in

asse

ssin

g li

ke

lih

oo

d

and

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Wat

er a

utho

rity

and

cu

stom

er p

lum

bing

and

pi

pe m

ater

ials

suc

h as

:• c

oppe

r se

rvic

e pi

pes

• old

gal

vani

sed

wro

ught

ir

on G

WI a

nd u

nlin

ed s

teel

pi

pes

and

hydr

ant

rise

rs• l

ead

join

ts a

nd s

ervi

ce

pipe

s• l

each

ing

of p

last

icis

ers

from

unp

last

icis

ed

poly

viny

lchl

orid

e (u

PVC

) pi

pe

• lea

chin

g of

lead

from

pre

-19

90 u

PVC

• lea

chin

g fr

om o

ld b

itum

en

linin

gs• l

each

ing

of p

oor

qual

ity

cem

ent

linin

gs• l

each

ing

from

pla

stic

co

ated

val

ves,

rubb

er

hose

s (e

g. ki

tche

n m

ixer

ta

ps a

nd d

ishw

ashe

r in

let

hose

s)

• Che

mic

al

cont

amin

atio

n -

co

pper

, iro

n, le

ad

• Pol

yaro

mat

ic

hydr

ocar

bons

• Sus

pend

ed s

olid

s• A

lkal

inity

• Pla

stic

iser

s• M

icro

biol

ogic

al

cont

amin

atio

n• T

aste

and

odo

ur

com

poun

ds -

from

pl

astic

coa

ted

and

rubb

er h

oses

and

fi t

tings

• Com

plia

nce

with

pl

umbi

ng c

odes

and

Pl

umbi

ng In

dust

ry C

ounc

il re

com

men

datio

ns• S

ensi

tivity

of c

usto

mer

s (e

g. ho

spita

ls, b

ever

age

indu

stri

es, i

nfan

ts o

r ag

ed

peop

le)

• Pip

e m

ater

ials

, typ

e an

d ag

e• S

tabi

lity

and

corr

osiv

ity o

f su

pplie

d w

ater

• Typ

es a

nd lo

catio

n of

cu

stom

er c

ompl

aint

s an

d av

aila

ble

reco

rds

of

com

plai

nts

• Kno

wle

dge

and

leve

l of

mon

itori

ng o

f wat

er q

ualit

y w

ithin

the

sys

tem

• Cop

per,

iron

and

lead

le

vels

with

in s

ewag

e sl

udge

• Leg

al r

espo

nsib

ilitie

s an

d im

pact

s of

exi

stin

g cu

stom

er c

ontr

acts

• Lim

its o

f res

pons

ibili

ty

and

cont

ract

s be

twee

n cu

stom

ers

and

wat

er

auth

ority

• Wat

er q

ualit

y (s

tabi

lisat

ion)

• Dis

infe

ctio

n• C

usto

mer

adv

ice

and

educ

atio

n• I

nspe

ctio

ns• L

icen

sing

of p

lum

bers

• Ban

ning

of m

ater

ials

not

su

itabl

e fo

r co

ntac

t w

ith

drin

king

wat

er b

y Pl

umbi

ng

Indu

stry

Cou

ncil

• Plu

mbi

ng c

odes

• Rep

lace

men

t of

old

unl

ined

st

eel,

galv

anis

ed w

roug

ht

iron

; bitu

men

line

d m

ains

, le

ad s

ervi

ce p

ipes

and

lead

jo

inte

d m

ains

• Rev

iew

his

tory

/ oc

curr

ence

s / c

ompo

sitio

n of

com

plai

nts

• Mon

itor

old

uPV

C a

nd le

ad jo

inte

d m

ains

for

lead

in w

ater

• Kee

p go

od r

ecor

ds o

f inc

iden

ts a

nd c

ompl

aint

s by

loca

tion

and

type

• Pro

duce

gui

danc

e do

cum

ents

to

educ

ate

cust

omer

s ab

out

haza

rds

with

in

plum

bing

. Ens

ure

plum

bing

cod

es a

nd P

IC r

ecom

men

datio

ns a

re e

nfor

ced

• Ins

pect

new

plu

mbi

ng• T

est

new

pip

e m

ater

ials

for

wat

er q

ualit

y ha

zard

s• M

easu

re w

ater

qua

lity,

corr

osiv

ity a

nd p

H in

cem

ent

lined

pip

e es

tate

s• S

peci

fy d

esig

n an

d w

ater

qua

lity

requ

irem

ents

for

priv

ate

wat

er s

uppl

ies

• Elim

inat

e un

lined

iron

and

GW

I pip

es• M

easu

re le

vels

of c

oppe

r, ir

on a

nd le

ad in

sew

age

slud

ge• S

eek

lega

l adv

ice

rega

rdin

g th

e po

tent

ial i

mpa

ct o

f exi

stin

g cu

stom

er c

ontr

acts

or

cre

ate

new

con

trac

ts• E

nsur

e hi

gh C

O2

curi

ng o

f new

cem

ent-

lined

pip

es a

t fa

ctor

y• D

o no

t us

e ce

men

t lin

ed p

ipes

in n

ew e

stat

es w

here

det

entio

n tim

es fo

r w

ater

in

pip

e is

> 2

4 ho

urs

Oth

er

rela

ted

Fac

t S

he

ets

: •

16. W

TP

Cap

abili

ty -

Alk

alin

ity•

33. B

ackfl

ow

and

Cro

ss C

onne

ctio

ns in

Pip

elin

es


66

32

. Hig

h F

low

in

Pip

eli

ne

sS

ou

rce

of

Haz

ard

/Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

Me

asu

res

Su

gge

stio

ns

for

Co

nsi

de

rati

on

Hig

h fl o

w a

nd r

apid

ch

ange

s in

fl ow

rate

in

pip

elin

es -

cau

sing

sc

ouri

ng a

nd

slou

ghin

g of

slim

es

and

sedi

men

t

• Tu

rbid

ity•

Mic

robi

olog

ical

co

ntam

inat

ion

-fr

om b

iofi l

ms

• Fr

eque

ncy

and

mag

nitu

de o

f hig

h ve

loci

ties

(>0.

6 m

/s)

• Si

ze a

nd le

ngth

of a

ffect

ed p

ipes

• N

umbe

r of

cus

tom

ers

affe

cted

• Se

nsiti

vity

of c

usto

mer

s (e

g. be

vera

ge m

anuf

actu

rers

, hos

pita

ls)

• N

orm

al w

ater

qua

lity

and

chan

ges

to q

ualit

y, eg

. dis

infe

ctio

n, s

uspe

nded

so

lids,

orga

nics

, Mn,

Fe

• Sp

eed

of c

hang

e of

wat

er q

ualit

y ca

usin

g sl

ough

ing

(eg.

disi

nfec

tant

re

sidu

al, i

onic

com

posi

tion)

• A

bilit

y to

con

trol

fl ow

rat

es in

pi

pelin

es•

Nat

ure

of s

limes

and

sed

imen

ts•

Effe

ctiv

enes

s of

cle

anin

g pr

oced

ures

• H

isto

ry o

f dir

ty w

ater

com

plai

nts

• K

now

ledg

e an

d le

vel o

f mon

itori

ng

of fl

ow r

ates

and

wat

er q

ualit

y w

ithin

the

sys

tem

• G

ood

desi

gn•

Incr

ease

d pi

pe n

etw

ork

capa

city

• D

ocum

ente

d op

erat

iona

l pr

oced

ures

• A

utom

atic

fl ow

con

trol

- in

clud

ing

max

fl ow

lim

its•

Insp

ectio

nPr

e-tr

eatm

ent

of w

ater

to:

• m

axim

ise

disi

nfec

tant

pen

etra

tion

• re

mov

e su

spen

ded

solid

s,

orga

nics

, man

gane

se a

nd ir

on

• A

dd li

ning

or

repl

ace

unlin

ed c

ast

iron

mai

ns•

Acc

ess

to a

ltern

ativ

e su

pplie

s•

Dum

ping

of d

irty

wat

er•

Reg

ular

cle

anin

g of

vul

nera

ble

area

s be

fore

spr

ing

/ sum

mer

hig

h fl o

ws

• Id

entif

y ar

eas

with

his

tory

of d

irty

wat

er a

ssoc

iate

d w

ith h

igh

fl ow

rate

eve

nts.

Use

the

res

ults

of t

his

revi

ew t

o de

term

ine

appr

opri

ate

prev

entiv

e m

easu

res

• D

evel

op w

ritt

en o

pera

tiona

l pro

cedu

res

to m

inim

ise

high

fl ow

si

tuat

ions

• Id

entif

y se

nsiti

ve u

sers

• Fo

rmal

ise

emer

genc

y co

ntac

ts•

Dev

elop

inci

dent

and

em

erge

ncy

proc

edur

es t

o m

inim

ise

impa

ct

of p

oor

wat

er q

ualit

y•

Ass

ess

wat

er q

ualit

y fo

r sl

ime

pote

ntia

l•

Equi

pmen

t se

lect

ion

/ de

sign

/ co

ntro

l to

min

imis

e pe

ak fl

ow a

nd

the

rate

of c

hang

e in

fl ow

• Pe

rfor

m h

ydra

ulic

mod

ellin

g to

iden

tify

high

ris

k ar

eas

(eg.

rapi

d w

ater

qua

lity

vari

atio

n, in

term

itten

t hi

gh v

eloc

ities

)•

By m

anag

ing

dem

and,

the

pea

k de

man

d an

d th

us p

eak fl o

w c

an b

e re

duce

d•

Insp

ect

/ mon

itor

vuln

erab

le a

reas

, eg.

inst

all s

tubs

on

pipe

s, co

upon

s, de

wat

er p

ipes

and

insp

ect

inte

rnal

sur

face

s et

c

Oth

er

rela

ted

Fac

t S

he

ets

: •

29. P

ipel

ine

Rep

airs

and

Mai

nten

ance

• 30

. Cle

anin

g of

Mai

ns•

34. R

ever

se F

low

in P

ipel

ines


67

33

. Bac

kfl

ow

an

d C

ross

Co

nn

ect

ion

s in

Pip

eli

ne

sS

ou

rce

of

Haz

ard

/E

ven

tT

ypic

al H

azar

ds

Fac

tors

to

co

nsi

de

r in

as

sess

ing

lik

eli

ho

od

an

d

seve

rity

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Backfl o

w fr

om

cons

umer

- e

g .

from

rai

nwat

er t

ank,

in

dust

rial

pro

cess

and

sw

imm

ing

pool

s

Cro

ss c

onne

ctio

ns

- fr

om r

euse

pip

elin

es,

priv

ate

wat

er s

uppl

ies,

brok

en s

ewer

age

mai

ns

• Mic

robi

olog

ical

co

ntam

inat

ion

-in

clud

ing

biofi

lms

• Che

mic

al

cont

amin

atio

n -

in

dust

rial

che

mic

als

• Tas

te a

nd o

dour

co

mpo

unds

• Num

ber

and

type

s of

indu

stri

al

plan

ts c

onne

cted

to

syst

em• C

ompl

ianc

e w

ith p

lum

bing

cod

es• S

ensi

tivity

of c

usto

mer

s (e

g. ho

spita

ls, b

ever

age

indu

stri

es,

infa

nts

or a

ged

peop

le)

• Pot

entia

l for

neg

ativ

e / l

ow

pres

sure

s• N

umbe

r an

d qu

ality

of p

riva

te

wat

er s

uppl

ies

• Kno

wle

dge

of s

yste

m, l

evel

of

mon

itori

ng o

f sys

tem

ope

ratio

n an

d w

ater

qua

lity.

• Des

ign

and

exte

nt o

f reu

se

sche

mes

• Ins

pect

ion

• App

ly p

lum

bing

cod

es• G

ood

pipe

net

wor

k de

sign

• Air

gap

s• D

oubl

e no

n-re

turn

va

lves

• Flo

w c

ontr

ol a

nd fl

ow

mon

itori

ng

• Ass

ess

loca

tion,

freq

uenc

y an

d co

mpo

sitio

n of

wat

er q

ualit

y co

mpl

aint

s to

det

ect

any

sign

s of

bac

kfl o

w p

robl

ems

• Kee

p go

od r

ecor

ds o

f inc

iden

ts a

nd c

ompl

aint

s w

hich

cou

ld r

elat

e to

bac

kfl o

w

even

ts• D

evel

op w

ritt

en p

roce

dure

s an

d co

des

for

desi

gn o

f bac

kfl o

w p

reve

ntio

n sy

stem

s an

d pl

umbi

ng m

etho

ds• E

nsur

e pr

oced

ures

and

cod

es a

re e

nfor

ced

• Ide

ntify

sen

sitiv

e us

ers,

and

form

alis

e em

erge

ncy

resp

onse

pla

ns in

clud

ing

cont

acts

and

not

ifi ca

tions

• Ins

tall

backfl o

w p

reve

nter

s su

ch a

s do

uble

non

-ret

urn

valv

es w

here

ver

requ

ired

• Spe

cify

des

ign

and

wat

er q

ualit

y re

quir

emen

ts fo

r pr

ivat

e w

ater

sup

plie

s• C

olou

r co

ding

of r

euse

pip

es a

nd fi

ttin

gs t

o cl

earl

y di

stin

guis

h fr

om p

otab

le

wat

er• I

nspe

ct in

dust

rial

site

s et

c. to

confi r

m b

ackfl

ow

pre

vent

ers

are

in p

lace

and

op

erat

iona

l• I

nsta

ll w

ater

met

ers

on fi

re s

ervi

ces

Oth

er

rela

ted

Fac

t S

he

ets

: •

31. P

ipe

Mat

eria

ls, P

riva

te M

ains

, and

Cus

tom

er P

lum

bing

• 32

. Hig

h Fl

ow in

Pip

elin

es•

34. R

ever

se F

low

in P

ipel

ines


68

34

. Re

vers

e F

low

in

Pip

eli

ne

sS

ou

rce

of

Haz

ard

/Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Rev

erse

fl ow

inpi

pelin

es c

ausi

ng:

• sco

urin

g of

slim

es

and

sedi

men

ts• n

egat

ive

pres

sure

s

• Mic

robi

olog

ical

co

ntam

inat

ion

-

from

ingr

ess

at

join

ts• T

urbi

dity

• Fre

quen

cy a

nd m

agni

tude

of p

eak fl o

ws

(>0.

6 m

/s)

• Siz

e an

d le

ngth

of a

ffect

ed p

ipes

• Num

ber

of c

usto

mer

s af

fect

ed• S

ensi

tivity

of c

usto

mer

s (e

g. be

vera

ge

man

ufac

ture

rs, h

ospi

tals

)• A

bilit

y to

con

trol

fl ow

rat

es in

pip

elin

es• H

isto

ry o

f dir

ty w

ater

com

plai

nts

• Kno

wle

dge

and

leve

l of m

onito

ring

of fl

ow

ra

tes

and

wat

er q

ualit

y w

ithin

the

sys

tem

• Pip

e m

ater

ials

, joi

nt c

ondi

tion

and

age

of p

ipe

• Pre

senc

e of

sys

tem

hig

h po

ints

exa

cerb

atin

g ne

gativ

e pr

essu

res

• Fir

e de

man

ds r

educ

ing

pres

sure

s• A

ir v

alve

loca

tions

and

con

ditio

n• H

ydra

nts

may

act

as

ingr

ess

poin

ts in

ne

gativ

e pr

essu

re s

ituat

ions

• Pot

entia

l wat

er h

amm

er• N

atur

e of

slim

es a

nd s

edim

ents

• Goo

d de

sign

(eg

. elim

inat

e bo

ttle

neck

join

ts)

• Inc

reas

ed p

ipe

netw

ork

capa

city

• Reg

ular

cle

anin

g of

vul

nera

ble

area

s be

fore

spr

ing

/ sum

mer

hi

gh fl

ows

• Wri

tten

ope

ratio

nal p

roce

dure

s• A

utom

atic

fl ow

con

trol

• L

inin

g or

rep

lace

any

unl

ined

cas

t ir

on m

ains

• Pre

ssur

e zo

ne b

ound

arie

s• S

low

act

ing

pres

sure

con

trol

va

lves

• Des

ign

to a

void

acc

umul

atio

n of

se

dim

ents

• Min

imis

e or

gani

cs, s

edim

ent,

man

gane

se, a

nd ir

on e

ntry

• Max

imis

e di

sinf

ecta

nt p

enet

ratio

n

• Ide

ntify

are

as w

ith a

his

tory

of d

irty

wat

er t

hat

mig

ht b

e as

soci

ated

with

rev

erse

fl ow

eve

nts,

and

anal

yse

such

are

as

for

reve

rse fl o

w. U

se t

he r

esul

ts o

f thi

s re

view

to

dete

rmin

e ap

prop

riat

e pr

even

tive

mea

sure

s• D

evel

op d

ocum

ente

d op

erat

iona

l pro

cedu

res

to m

inim

ise

reve

rse

fl ow

situ

atio

ns• I

dent

ify s

ensi

tive

user

s an

d fo

rmal

ise

emer

genc

y re

spon

se p

lans

in

clud

ing

cont

acts

• Dev

elop

inci

dent

man

agem

ent

proc

edur

es t

o m

inim

ise

impa

ct o

f po

or w

ater

qua

lity

• Equ

ipm

ent

sele

ctio

n /

desi

gn /

cont

rol t

o m

inim

ise

peak

fl ow

and

th

e ra

te o

f cha

nge

in fl

ow• P

erfo

rm h

ydra

ulic

mod

ellin

g to

iden

tify

high

vel

ocity

pip

es• B

y m

anag

ing

dem

and,

the

pea

k de

man

d a

nd t

hus

peak

fl ow

can

be

redu

ced

• Ens

ure

leak

ing

pipe

s an

d jo

ints

are

fi xe

d• R

evie

w lo

catio

ns o

f hyd

rant

s an

d ai

r va

lves

Oth

er

rela

ted

Fac

t S

he

ets

: •

30. C

lean

ing

of M

ains

• 32

. Hig

h Fl

ow in

Pip

elin

es•

33. B

ackfl

ow

and

Cro

ss C

onne

ctio

ns in

Pip

elin

es


69

35

. Sta

gnan

t W

ate

r in

Pip

eli

ne

sS

ou

rce

of

Haz

ard

/Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Stag

nant

wat

er in

pi

pelin

es c

ause

d by

:• d

ead

ends

• cul

-de-

sac

stre

ets

with

low

wat

er

dem

ands

• ove

rsiz

ed

dist

ribu

tion

mai

ns

in n

ew e

stat

es

• Mic

robi

olog

ical

co

ntam

inat

ion

-

from

low

chl

orin

e re

sidu

als

and

low

di

ssol

ved

oxyg

en• A

lkal

inity

• Tas

te a

nd o

dour

co

mpo

unds

• Low

chl

orin

e re

sidu

als

• Low

dis

solv

ed o

xyge

n

• Dur

atio

n of

ver

y lo

w fl

ows

• Det

entio

n tim

es in

low

fl ow

pip

ewor

k• S

ize

and

leng

th o

f affe

cted

pip

es• N

umbe

r of

cus

tom

ers

affe

cted

• Sen

sitiv

ity o

f cus

tom

ers

(eg.

beve

rage

m

anuf

actu

rers

, hos

pita

ls)

• Nor

mal

wat

er q

ualit

y an

d va

riat

ions

in q

ualit

y -

eg. d

isin

fect

ion,

sus

pend

ed s

olid

s, or

gani

cs,

man

gane

se, i

ron

• Pot

entia

l cha

nges

to

sour

ces

of w

ater

cau

sing

ta

ste

and

odou

r pr

oble

ms

• Abi

lity

to c

ontr

ol fl

ow r

ates

in p

ipel

ines

• Effe

ctiv

enes

s of

fl us

hing

and

cle

anin

g pr

oced

ures

• His

tory

of t

aste

and

odo

ur c

ompl

aint

s an

d pe

ak c

olifo

rm le

vels

• Kno

wle

dge

and

leve

l of m

onito

ring

of fl

ow

ra

tes

and

wat

er q

ualit

y w

ithin

the

sys

tem

• Pip

e m

ater

ials

and

age

of p

ipe

• Typ

ical

ope

ratio

n of

ser

vice

res

ervo

irs

with

co

mm

on in

let

/ out

let

pipe

s

• Goo

d de

sign

of p

ipel

ines

• Flu

shin

g es

peci

ally

at

clos

ed

valv

es a

long

pre

ssur

e zo

ne

boun

dari

es• R

educ

e pi

pe d

iam

eter

s an

d du

plic

ate

mai

ns w

hen

need

ed• W

ritt

en o

pera

tiona

l pr

oced

ures

• Aut

omat

ic fl

ow c

ontr

ol

• Cle

anin

gPr

e-tr

eatm

ent

of w

ater

to:

• max

imis

e di

sinf

ecta

nt

pene

trat

ion

• rem

ove

susp

ende

d so

lids,

orga

nics

, man

gane

se, i

ron

• Min

imis

e us

e of

cem

ent

lined

pip

es o

r at

leas

t ca

rbon

di

oxid

e cu

re a

nd s

eal c

oat

• Aut

omat

ic fl

ushi

ng d

evic

es• E

limin

atio

n of

com

mon

inle

t / o

utle

t pi

pes

at s

ervi

ce

rese

rvoi

rs

• Ass

ess

loca

tion,

freq

uenc

y, an

d co

mpo

sitio

n of

wat

er q

ualit

y co

mpl

aint

s to

det

ect

asso

ciat

ion

with

sta

gnan

t ar

eas

• Des

ign

syst

em t

o av

oid

crea

ting

stag

nant

are

as (

eg m

inim

ise

cour

ts)

• Est

ablis

h m

inim

um fl

ow c

rite

ria

for

larg

e di

amet

er m

ains

• Elim

inat

e co

mm

on in

let

/ out

lets

for

tank

s• D

evel

op w

ritt

en p

roce

dure

s to

avo

id r

ever

se fl

ow s

ituat

ions

• Ide

ntify

sen

sitiv

e us

ers,

and

form

alis

e em

erge

ncy

resp

onse

pla

ns

incl

udin

g co

ntac

ts a

nd n

otifi

catio

n pr

otoc

ols

• Mon

itor

for

low

dis

solv

ed o

xyge

n le

vels

and

hig

h pH

(al

kalin

ity)

• Rev

iew

wat

er q

ualit

y fo

r ta

ste

and

odou

r / c

hlor

ine

dem

and

pote

ntia

l• U

tilis

e go

od n

etw

ork

desi

gn a

nd fl

ow m

anag

emen

t to

avo

id

stag

nant

are

as• U

se fl

uori

de t

race

r te

sts

• Wat

er p

H b

uffe

ring

• Per

form

hyd

raul

ic m

odel

ling

to id

entif

y hi

gh r

isk

area

s• C

hoos

e pi

pe m

ater

ials

and

pip

e lin

ings

to

avoi

d hi

gh p

H

Oth

er

rela

ted

Fac

t S

he

ets

: •

30. C

lean

ing

of M

ains

• 32

. Hig

h Fl

ows

in P

ipel

ines

• 33

. Bac

kfl o

w a

nd C

ross

Con

nect

ions

in P

ipel

ines


70

36

. Aq

ue

du

cts

No

te: M

any

issue

s af

fect

ing

aque

duct

s ar

e th

e sa

me

as th

ose

affe

ctin

g ca

tchm

ents

, res

ervo

irs a

nd p

ipel

ines

. Re

fer

to th

e Fa

ct S

heet

s as

list

ed b

elow

tabl

e.

So

urc

e o

f H

azar

d/

Eve

nt

Typ

ical

Haz

ard

sF

acto

rs t

o c

on

sid

er

in a

sse

ssin

g li

ke

lih

oo

d a

nd

se

veri

ty

Typ

ical

Pre

ven

tive

M

eas

ure

sS

ugg

est

ion

s fo

r C

on

sid

era

tio

n

Con

tam

inat

ion

of

aque

duct

s by

:• d

row

ned

anim

als

• sew

age

overfl o

ws

• infi

ltra

tion

• lea

kage

from

sto

rm

wat

er p

ipes

cro

ssin

g th

e aq

uedu

ct• o

verfl

ow

of s

torm

w

ater

cat

ch d

rain

s• h

uman

acc

ess

incl

udin

g sa

bota

ge• a

lgae

blo

om t

hen

scou

r• t

ree

and

plan

t lit

ter

deco

mpo

sitio

n• r

unof

f fro

m r

oads

, br

idge

s an

d ac

cide

ntal

sp

ills

• pes

ticid

e dr

ift

• Mic

robi

olog

ical

co

ntam

inat

ion

- e

g. al

gae,

dea

d an

imal

s an

d pl

ants

, sew

age,

lit

ter

• Che

mic

al

cont

amin

atio

n -

al

gici

des,

pes

ticid

es,

inse

ctic

ides

, he

rbic

ides

, in

dust

rial

che

mic

als,

petr

oche

mic

als,

haza

rdou

s m

ater

ials

• Tas

te a

nd o

dour

co

mpo

unds

• Col

our

• Nat

ural

org

anic

m

atte

r• T

urbi

dity

• Fre

quen

cy o

f ins

pect

ions

and

cle

anin

g• E

ffect

iven

ess

of c

lean

ing

proc

edur

es• P

assa

ge o

f aqu

educ

t th

roug

h un

sew

ered

urb

an

area

s• l

andu

se w

ithin

1 k

m o

f aqu

educ

t al

ignm

ent

• Kno

wle

dge

of s

yste

m o

pera

tions

• Ext

ent

and

resu

lts o

f mon

itori

ng o

f wat

er q

ualit

y• A

dequ

acy

of in

spec

tions

and

sev

erity

rat

ing

• Num

ber

of p

riva

te c

onne

ctio

ns (

supp

ly b

y ag

reem

ent)

• Nut

rien

t le

vel i

n w

ater

• Pre

senc

e of

litt

er r

acks

/ sc

reen

s• A

lgic

ide

use

• Fre

quen

cy o

f occ

urre

nce

of E

. col

i• A

nim

al c

ontr

ol m

easu

res

• Abi

lity

for

anim

als

to g

et o

ut o

f aqu

educ

t• A

bilit

y to

pro

secu

te t

resp

asse

rs• L

egal

res

pons

ibili

ties

• Agr

icul

tura

l act

iviti

es n

earb

y (e

g. sp

rayi

ng w

ith

herb

icid

e / p

estic

ide)

• Lev

el o

f usa

ge o

f roa

ds c

ross

ing

or p

assi

ng n

ear

aque

duct

• Sur

veill

ance

pat

rols

and

fe

ncin

g• I

nspe

ctio

n, c

lean

ing

and

mai

nten

ance

• Cat

ch d

rain

s• I

nter

mitt

ent

use

of a

lgic

ide

• Elim

inat

e pr

ivat

e co

nnec

tions

• Cov

er a

qued

ucts

• Cov

er o

r sy

phon

s at

roa

d cr

ossi

ngs

• Ove

rhan

ging

or

near

by t

ree

mai

nten

ance

and

con

trol

• App

ropr

iate

des

ign

of s

torm

w

ater

pip

e cr

ossi

ngs

• Mon

itori

ng o

f wat

er q

ualit

y al

ong

aque

duct

(eg

. bac

teri

a)

• Mon

itor

qual

ity o

f wat

er a

t aq

uedu

ct in

let

and

outle

t, an

d al

ong

leng

th, a

nd r

elat

e to

pos

sibl

e co

ntam

inan

t in

gres

s• R

evie

w a

nd m

aint

ain

good

rec

ords

of i

ncid

ents

(eg

. ani

mal

ac

cess

, spi

lls)

• Elim

inat

e op

en a

qued

ucts

whe

re p

ossi

ble,

esp

ecia

lly

thro

ugh

tow

ns• E

nsur

e le

ak in

spec

tion

and

clea

ning

str

ateg

ies

are

adeq

uate

• Ins

tall fl o

w c

ontr

ol /

mon

itori

ng s

yste

ms

• Ere

ct s

ecur

ity fe

ncin

g to

pre

vent

ani

mal

/ hu

man

acc

ess

• Cov

er a

t ro

ad c

ross

ings

to

prev

ent

cont

amin

atio

n by

roa

d ru

noff

or s

pills

• Whe

re p

ossi

ble

rem

ove

traffi c

cro

ssin

g po

ints

• Rev

iew

and

lim

it ag

ricu

ltura

l pra

ctic

es n

ear

aque

duct

s• R

emov

e tr

ees

to p

reve

nt e

ntry

of c

onta

min

ated

leaf

litt

er• E

nsur

e w

ater

is t

reat

ed a

t do

wns

trea

m e

nd o

f the

ope

n aq

uedu

ct (

eg. w

ith c

hlor

ine)

• Pro

vide

cov

er, o

r en

tirel

y re

plac

e w

ith p

ipe

• Ins

tall

conc

rete

lini

ng o

f aqu

educ

t

Oth

er

rela

ted

Fac

t S

he

ets

: •

Fact

She

ets

rela

ted

to P

ipel

ines

: 29

- 35

• Fa

ct S

heet

s re

latin

g to

Cat

chm

ents

and

Res

ervo

irs:

1 -

13


71

Appendix BCase Studies


72

Cas

e S

tud

y 1 -

Bac

kfl

ow

in

Pip

eli

ne

sC

ause

Backfl o

w o

f con

tam

inat

ed w

ater

into

the

dis

trib

utio

n sy

stem

.

Sour

ce o

f haz

ard:

sew

age

Haz

ard:

m

icro

bial

pat

hoge

nsLi

kelih

ood:

rare

A v

eget

able

pro

cess

ing

fact

ory

had

ceas

ed t

o us

e th

e to

wn

wat

er s

uppl

y fo

r fo

od p

roce

ssin

g af

ter

inst

allin

g its

ow

n gr

ound

wat

er b

ore.

Aft

er s

ever

al y

ears

of o

pera

tion,

th

e pu

mp

on t

he b

ore

faile

d an

d a

smal

ler

spar

e pu

mp

was

use

d to

dra

w w

ater

from

the

nea

rby

rive

r (d

owns

trea

m o

f a s

ewag

e ou

tfl ow

) w

hile

rep

airs

wer

e be

ing

mad

e.T

he fl

ow r

ate

from

the

sm

alle

r pu

mp

was

inad

equa

te, s

o th

e va

lve

conn

ectin

g th

e fa

ctor

y to

the

tow

n w

ater

sup

ply

was

reo

pene

d to

sup

plem

ent

the

supp

ly. T

he p

ump

pres

sure

was

hig

her

than

the

ave

rage

mai

ns p

ress

ure,

res

ultin

g in

bac

kfl o

w o

f con

tam

inat

ed r

iver

wat

er in

to t

he d

istr

ibut

ion

syst

em.

Indi

cato

rs o

f Haz

ard

Cus

tom

er c

ompl

aint

s of

dir

ty w

ater

4 d

ays

afte

r th

e fa

ctor

y w

as r

econ

nect

ed t

o th

e to

wn

supp

ly.H

igh

faec

al c

olifo

rm c

ount

s w

ere

reco

rded

in t

he m

ains

wat

er.

Mea

sure

d Le

vels

of H

azar

dH

igh

leve

ls o

f mic

robi

olog

ical

con

tam

inat

ion

indi

cate

d by

>10

4 faec

al c

olifo

rms/

100m

L in

the

wat

er q

ualit

y zo

ne n

eare

st t

he c

onta

min

atio

n po

int.

It w

as e

stim

ated

tha

t ab

out

320

cubi

c m

etre

s of

riv

er w

ater

had

bee

n pu

mpe

d in

to t

he d

rink

ing

wat

er s

uppl

y, co

rres

pond

ing

to 1

0% o

f the

vill

age’

s co

nsum

ptio

n du

ring

thi

s 4½

day

per

iod.

Effe

ctIn

the

21

days

follo

win

g th

e on

set

of t

he c

onta

min

atio

n, 6

5% o

f the

1,1

50 r

esid

ents

suf

fere

d ga

stro

ente

ritis

. In

fect

ions

with

Cam

pylo

bact

er a

nd E

. col

i O15

7 w

ere

diag

nose

d (8

and

6 c

ases

, res

pect

ivel

y, la

bora

tory

confi r

med

), in

clud

ing fi v

e pe

ople

req

uiri

ng h

ospi

talis

atio

n.

Two

child

ren

deve

lope

d th

e po

tent

ially

fata

l con

ditio

n H

US

(hae

mol

ytic

ure

mic

syn

drom

e) a

s a

resu

lt of

E. c

oli O

157

infe

ctio

n (la

bora

tory

confi r

med

) bu

t re

cove

red.

All

othe

r pa

tient

s al

so m

ade

full

reco

veri

es.

Liab

ility

• C

osts

of h

yper

chlo

rina

tion

and fl u

shin

g of

sys

tem

• C

osts

of p

rovi

sion

of a

ltern

ativ

e w

ater

sup

plie

s•

Cos

ts o

f pub

lic h

ealth

inve

stig

atio

n•

Cos

ts o

f med

ical

tre

atm

ent

for

affe

cted

peo

ple

• C

osts

for

time

lost

from

wor

k by

affe

cted

peo

ple

• Le

gal a

ctio

n fo

r ill

ness

cau

sed

by t

he o

utbr

eak

Prev

entiv

e M

easu

res

• Ba

ckfl o

w p

rote

ctio

n de

vice

s.

Ref

eren

ces

Jone

s, I.

G. a

nd M

. Row

orth

(Se

pt. 1

996)

. An

outb

reak

of E

sche

richi

a co

li O

157

and

Cam

pylo

bact

erio

sis

asso

ciat

ed w

ith c

onta

min

atio

n of

a d

rink

ing

wat

er s

uppl

y. P

ublic

H

ealth

110

(5):

277

–282

.

Loca

tion

and

Dat

eFi

fe, S

cotla

nd, U

K.

1995

.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

31

. Pip

e M

ater

ials

, Pri

vate

Mai

ns, a

nd C

usto

mer

Plu

mbi

ng

33. B

ackfl

ow

and

Cro

ss C

onne

ctio

ns in

Pip

elin

es


73

Cas

e S

tud

y 2 -

In

ade

qu

ate

Dis

infe

ctio

n o

f S

ou

rce

Wat

er

Cau

seIn

adeq

uate

dis

infe

ctio

n of

riv

er w

ater

sup

ply.

Sour

ce o

f haz

ard:

sew

age

Haz

ard:

m

icro

bial

pat

hoge

nsLi

kelih

ood:

expe

cted

eve

ry y

ear

An

outb

reak

of g

astr

oent

eriti

s oc

curr

ed o

ver

a si

x w

eek

peri

od in

a t

own

serv

ed b

y a

sand

fi lte

red

and

chlo

rina

ted

rive

r w

ater

sup

ply.

Epid

emio

logi

cal i

nves

tigat

ions

sho

wed

tha

t th

ose

drin

king

tap

wat

er h

ad a

3.5

tim

es g

reat

er r

isk

of il

lnes

s th

an t

hose

dri

nkin

g w

ater

from

alte

rnat

ive

sour

ces,

and

ther

e w

as n

o as

soci

atio

n of

illn

ess

with

food

sou

rces

. A

rev

iew

of w

ater

tre

atm

ent

plan

t re

cord

s sh

owed

inad

equa

te c

hlor

inat

ion

with

leve

ls u

sual

ly r

angi

ng fr

om 0

.07

to 0

.3 m

g/lit

re, w

hile

the

sta

ted

targ

et v

alue

was

0.8

m

g/lit

re.

Sew

age

effl u

ent

with

a h

igh

path

ogen

load

from

an

upst

ream

tow

n th

at h

ad e

xper

ienc

ed a

food

born

e N

orw

alk-

like-

viru

s (N

LV)

outb

reak

, coi

ncid

ing

with

in

adeq

uate

dis

infe

ctio

n, w

as im

plic

ated

as

the

mos

t lik

ely

caus

e of

the

out

brea

k.

Indi

cato

rs o

f Haz

ard

Tota

l chl

orin

e le

vel m

easu

red

at <

0.03

mg/

L, a

nd t

otal

col

iform

s 35

cfu

/100

mL.

Mea

sure

d Le

vels

of H

azar

dN

LV w

as d

etec

ted

by P

CR

in 1

litr

e sa

mpl

es o

f unt

reat

ed w

ater

, tre

ated

wat

er a

nd w

ater

from

the

dis

trib

utio

n sy

stem

(vi

rus

conc

entr

atio

n no

t st

ated

).

Effe

ctA

bout

hal

f of t

he p

opul

atio

n of

2,1

00 p

eopl

e ex

peri

ence

d ill

ness

, and

Nor

wal

k-lik

e vi

rus

(NLV

) w

as d

etec

ted

in c

linic

al s

peci

men

s fr

om a

ffect

ed p

eopl

e.

NLV

typ

ical

ly p

rodu

ces

inte

nse

but

shor

t du

ratio

n sy

mpt

oms,

and

only

abo

ut 5

0 of

the

infe

cted

peo

ple

soug

ht m

edic

al t

reat

men

t. H

owev

er o

ver

800

wor

king

day

s w

ere

lost

and

tot

al c

osts

for

the

outb

reak

wer

e es

timat

ed a

t U

S $3

00,0

00 [

1998

].

Liab

ility

• C

osts

of h

yper

chlo

rina

tion

and fl u

shin

g of

sys

tem

• C

osts

of p

rovi

sion

of a

ltern

ativ

e w

ater

sup

plie

s•

Cos

t of

tre

atm

ent

syst

em r

epai

rs/u

pgra

des

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

osts

of m

edic

al t

reat

men

t fo

r af

fect

ed p

eopl

e•

Cos

ts fo

r tim

e lo

st fr

om w

ork

by a

ffect

ed p

eopl

e•

Lega

l act

ion

for

illne

ss c

ause

d by

the

out

brea

k

Prev

entiv

e M

easu

res

• A

dequ

ate

disi

nfec

tion

with

con

tinuo

us o

n-lin

e m

onito

ring

of c

hlor

ine

leve

ls.

• O

n-lin

e m

onito

ring

of t

he fi

ltere

d w

ater

tur

bidi

ty fo

r ea

ch fi

lter.

Ref

eren

ces

M. K

ukku

la e

t alia

(19

99).

“O

utbr

eak

of v

iral

gas

troe

nter

itis

due

to d

rink

ing

wat

er c

onta

min

ated

by

Nor

wal

k-lik

e vi

ruse

s.” J

Infe

ct D

is 1

80

(6):

177

1–17

76.

Loca

tion

and

Dat

eFi

nlan

d. 1

998.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

1

– 9:

All

Cat

chm

ent

rela

ted

Fact

She

ets

23

. Dis

infe

ctio

n Sy

stem

Rel

iabi

lity

24

. Dis

infe

ctio

n Sy

stem

Des

ign

Cap

abili

ty


74

Cas

e S

tud

y 3 -

Co

nta

min

atio

n o

f W

ate

r S

up

ply

Sys

tem

an

d F

ailu

re o

f D

isin

fect

ion

Sys

tem

Cau

seC

onta

min

atio

n of

Wat

er S

uppl

y Sy

stem

and

Dis

infe

ctio

n Fa

ilure

.

Sour

ce o

f haz

ard:

envi

ronm

enta

l/agr

icul

tura

l/oth

er (

dead

ani

mal

s)H

azar

d:

mic

robi

al p

atho

gens

Like

lihoo

d:

ex

pect

ed e

very

ten

yea

rs o

r le

ss

The

Hal

ls o

f Res

iden

ce o

f a U

nive

rsity

in N

orth

ern

Engl

and

was

fed

by a

pri

vate

, unc

hlor

inat

ed s

urfa

ce w

ater

sup

ply.

The

wat

er w

as t

reat

ed b

y m

eans

of fi

ltra

tion

follo

wed

by

expo

sure

to

ultr

avio

let

(UV

) lig

ht.

Dea

d la

mb(

s) w

ere

foun

d in

the

wat

er s

uppl

y sy

stem

[no

det

ails

of t

he lo

catio

n pr

ovid

ed].

Add

ition

ally,

the

effe

ctiv

enes

s of

the

UV

ligh

ts w

as im

pair

ed d

ue t

o th

e ac

cum

ulat

ion

of d

epos

its o

ver

the

glas

s co

veri

ngs.

Indi

cato

rs o

f Haz

ard

Cas

es o

f ill

heal

th.

Mea

sure

d Le

vels

of H

azar

dEs

cher

ichi

a co

li w

as is

olat

ed fr

om w

ater

sam

ples

tak

en a

fter

the

out

brea

k.

Effe

ctIn

fect

ions

of C

rypt

ospo

ridiu

m s

p. a

nd C

ampy

loba

cter

sp.

wer

e di

agno

sed.

The

str

engt

h of

ass

ocia

tion

was

cla

ssed

as “

prob

able

,” ac

cord

ing

to e

pide

mio

logi

cal (

desc

ript

ive)

an

d m

icro

biol

ogic

al e

vide

nce.

T

here

was

a p

erio

d of

8 d

ays

betw

een

the

onse

t of

sym

ptom

s in

the

fi rs

t an

d la

st c

ase,

with

a t

otal

of 4

3 ca

ses

conf

orm

ing

to t

he c

ase

defi n

ition

for

the

outb

reak

. O

f th

ese

case

s, 5

case

s of

cry

ptos

pori

dios

is a

nd 8

cas

es o

f cam

pylo

bact

erio

sis

wer

e co

nfi r

med

by

labo

rato

ry a

naly

sis.

Tw

o ca

ses

requ

ired

hos

pita

lisat

ion.

T

his

com

pare

d to

a t

otal

of 6

0 pe

rson

s co

nsid

ered

“at

ris

k.”

Liab

ility

• C

osts

of h

yper

chlo

rina

tion

and fl u

shin

g of

sys

tem

• C

osts

of p

rovi

sion

of a

ltern

ativ

e w

ater

sup

plie

s•

Cos

t of

tre

atm

ent

syst

em r

epai

r/up

grad

e•

Cos

ts o

f pub

lic h

ealth

inve

stig

atio

n•

Cos

ts o

f med

ical

tre

atm

ent

for

affe

cted

peo

ple

• C

osts

for

time

lost

from

wor

k by

affe

cted

peo

ple

• Le

gal a

ctio

n fo

r ill

ness

cau

sed

by t

he o

utbr

eak

Prev

entiv

e M

easu

res

• A

dequ

ate

mai

nten

ance

of U

V d

isin

fect

ion

equi

pmen

t an

d fi l

trat

ion

syst

em.

• M

onito

ring

of a

nd r

espo

nse

to d

etec

tion

of E

sche

richi

a co

li.•

Mai

nten

ance

of b

arri

ers

limiti

ng a

cces

s to

wat

er s

uppl

y sy

stem

.

Ref

eren

ces

C. F

urta

do e

t alia

(19

98).

“O

utbr

eaks

of w

ater

born

e in

fect

ious

inte

stin

al d

isea

se [

IID]

in E

ngla

nd a

nd W

ales

, 199

2-5.

” E

pide

mio

l. In

fect

. 12

1:

109–

119.

R

. G. P

ebod

y et

alia

(7

Mar

ch 1

997)

. “O

utbr

eaks

of c

ampy

loba

cter

infe

ctio

n: r

are

even

ts fo

r a

com

mon

pat

hoge

n.”

Com

mun

icab

le D

isea

se R

epor

t [C

DR

] R

evie

w 7

(3):

R

33–R

37.

Loca

tion

and

Dat

eN

orth

ern

Engl

and,

UK

. M

ay 1

993.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

1

– 9:

All

Cat

chm

ent

rela

ted

Fact

She

ets

23

. Dis

infe

ctio

n Sy

stem

Rel

iabi

lity

24

. Dis

infe

ctio

n Sy

stem

Des

ign

Cap

abili

ty


75

Cas

e S

tud

y 4 -

Co

nta

min

atio

n o

f W

ate

r D

istr

ibu

tio

n S

yste

mC

ause

Con

tam

inat

ion

of W

ater

Dis

trib

utio

n Sy

stem

.

Sour

ce o

f haz

ard:

runo

ff of

cat

tle s

lurr

y an

d ‘m

uck’

(du

ng)

from

land

in t

he v

icin

ity o

f a b

roke

n w

ater

pip

eH

azar

d:

mic

robi

al p

atho

gens

Like

lihoo

d:

lik

ely

Two

tow

ns (

Saltc

oats

, pop

. 130

00 a

nd S

teve

nsto

n, p

op. 1

1000

) lo

cate

d ju

st o

ver

40km

Sou

th W

est

of G

lasg

ow, i

n co

asta

l Ayr

shir

e, w

ere

both

sup

plie

d w

ith w

ater

from

(t

reat

ed-w

ater

) st

orag

e ta

nks

at G

reen

head

Tre

atm

ent W

orks

.1 Thi

s w

ater

was

, in

turn

, dra

wn

from

Mun

noch

bre

ak-p

ress

ure

tank

, loc

ated

off

the

mai

n ch

lori

nate

d w

ater

tr

ansm

issi

on p

ipel

ine

out

of C

amph

ill T

reat

men

t Wor

ks. A

s th

e w

ater

was

alr

eady

tre

ated

at

Cam

phill

(an

d m

et a

ll re

quir

emen

ts fo

r th

e du

ratio

n of

the

out

brea

k), n

o fu

rthe

r tr

eatm

ent

occu

rred

at

Gre

enhe

ad. 2

A

n ol

d, b

roke

n 52

cm fi

re-c

lay

pipe

was

foun

d di

scha

rgin

g in

to t

he M

unno

ch b

reak

-pre

ssur

e ta

nk, c

olle

ctin

g ru

n-of

f. It

is li

kely

tha

t Cr

ypto

spor

idiu

m s

pp. o

ocys

ts w

ere

intr

oduc

ed t

o th

e di

stri

butio

n sy

stem

via

thi

s br

each

in t

he s

yste

m’s

inte

grity

, car

ried

in r

un-o

ff fr

om t

he s

urro

undi

ng c

atch

men

t ar

ea d

urin

g he

avy

rain

fall.

Fie

lds

in t

he

vici

nity

of t

he b

reak

-pre

ssur

e ta

nk h

ad b

een

spre

ad w

ith ‘m

uck’

(du

ng)

and

spra

yed

with

cat

tle s

lurr

y be

fore

the

out

brea

k, a

nd it

is p

roba

ble

that

the

cat

tle fa

eces

wer

e th

e so

urce

of t

he C

rypt

ospo

ridiu

m s

pp. o

ocys

ts, a

s th

e ou

tbre

ak c

oinc

ided

with

the

spr

ing

peak

of b

ovin

e cr

ypto

spor

idio

sis

in t

hat

area

. T

he d

iffi c

ulty

in p

in-p

oint

ing

the

sour

ce o

f the

con

tam

inat

ion

was

par

tly a

ttri

buta

ble

to t

he ir

regu

lar

natu

re o

f the

see

page

, bei

ng s

ignifi c

ant

only

aft

er p

erio

ds o

f rai

n.

Als

o, r

ecor

ds s

how

ed (

inco

rrec

tly)

that

the

pip

e ha

d be

en s

eale

d of

f man

y ye

ars

prev

ious

ly.

Indi

cato

rs o

f Haz

ard

On

5 A

pril

1988

the

loca

l Wat

er D

epar

tmen

t w

as in

form

ed o

f wat

er q

ualit

y fa

ilure

s id

entifi

ed

in r

outin

e ba

cter

iolo

gica

l tes

ting

of t

he d

istr

ibut

ion

wat

er (

see

belo

w).

A

lso

on 5

Apr

il, th

e lo

cal H

ealth

Boa

rd w

as n

otifi

ed t

hat

Cryp

tosp

orid

ium

spp

. ooc

ysts

had

bee

n id

entifi

ed

in t

he s

tool

s of

fi ve

pat

ient

s w

ithin

a fe

w d

ays

of e

ach

othe

r.

A 2

to

5-fo

ld in

crea

se in

the

loca

l inc

iden

ce o

f dia

rrho

ea w

as o

bser

ved.

Sub

sequ

ent

enqu

irie

s re

veal

ed t

hat “

man

y hu

ndre

ds o

f peo

ple”

had

suf

fere

d di

arrh

oeal

illn

ess

at

the

time.

Mea

sure

d Le

vels

of H

azar

dEs

cher

ichi

a co

li w

as id

entifi

ed

in t

he fi

rst

faile

d sa

mpl

e (s

ee a

bove

) of

22

Mar

ch (

10 p

er 1

00m

L) b

ut n

ot in

the

res

ampl

e of

29

Mar

ch. T

otal

col

iform

cou

nts

of 3

1 an

d 4c

fu/

100m

L w

ere

reco

rded

for

22 a

nd 2

9 M

arch

, res

pect

ivel

y. H

owev

er t

estin

g at

the

pla

nt o

n 3

Apr

il re

turn

ed n

egat

ive

read

ings

for

both

E. c

oli a

nd t

otal

col

iform

s.

The

Mun

noch

bre

ak-p

ress

ure

tank

alo

ng t

he t

rans

mis

sion

pip

elin

e w

as fo

und

to c

onta

in 0

.04

Cryp

tosp

orid

ium

spp

. ooc

ysts

per

litr

e [n

ot u

nusu

ally

hig

h]. T

he le

vels

in t

he

adja

cent

soi

l and

gra

ss w

ere

32 o

ocys

ts p

er g

ram

, and

ver

y hi

gh le

vels

of f

aeca

l con

tam

inat

ion

wer

e in

dica

ted

by b

acte

riol

ogic

al t

estin

g (1

52 c

olifo

rms,

107

E. c

oli a

nd 3

4 fa

ecal

str

epto

cocc

i per

100

mL)

. O

ocys

ts w

ere

dete

cted

in t

wo

of s

even

tre

ated

wat

er s

ampl

es (

one

as a

bove

and

the

oth

er 4

.8 o

ocys

ts/L

), in

the

abs

ence

of f

aeca

l bac

teri

a in

dica

tor

orga

nism

s. O

ocys

ts

wer

e al

so d

etec

ted

with

in t

he t

reat

men

t w

orks

(in

fi lte

r ba

ckw

ash

wat

er a

nd s

ludg

e), b

ut n

ot in

the

raw

wat

er e

nter

ing

or t

reat

ed w

ater

leav

ing

the

wor

ks.

How

ever

th

ese

sam

ples

wer

e ta

ken

tow

ards

the

end

of t

he o

utbr

eak.

Effe

ctA

lthou

gh t

he fi

rst fi v

e re

port

ed c

ases

wer

e re

late

d to

the

tow

n of

Sal

tcoa

ts o

nly,

resi

dent

s of

at

leas

t 6

tow

ns in

Sou

ther

n A

yrsh

ire

wer

e af

fect

ed.3

Tw

enty

-sev

en p

atie

nts

who

had

con

sum

ed t

he w

ater

wer

e di

agno

sed

as C

rypt

ospo

ridiu

m-p

ositi

ve. T

wen

ty-o

ne o

f the

se t

wen

ty-s

even

req

uire

d so

me

form

of fl

uid

-re

plac

emen

t th

erap

y.

Seve

ntee

n of

the

cas

es w

ere

child

ren

unde

r 9

year

s of

age

, whi

le t

he r

emai

ning

ten

wer

e ad

ults

ove

r th

e ag

e of

20.

4

Seve

ntee

n of

the

tw

enty

-sev

en c

ases

wer

e fe

mal

e.

Twel

ve c

ases

wer

e ad

mitt

ed t

o ho

spita

l, an

d 11

of t

hese

req

uire

d in

trav

enou

s fl u

id r

epla

cem

ent,

“mai

nly”

due

to

prol

onge

d or

rec

urre

nt v

omiti

ng.

How

ever

“in

no

inst

ance

was

the

illn

ess

life-

thre

aten

ing.”


76

Liab

ility

• C

osts

of b

oost

er c

hlor

inat

ion

and fl u

shin

g of

sys

tem

(in

itiat

ed a

t G

reen

head

on

6 A

pril)

• C

osts

of p

rovi

sion

of a

ltern

ativ

e w

ater

sup

plie

s (fr

om B

rada

n, 2

1 A

pril

1988

)•

Cos

t of

sys

tem

rep

airs

/upg

rade

s (in

clud

ing

seal

ing

of t

he fi

re-c

lay

pipe

with

a c

oncr

ete

plug

)•

Cos

ts o

f pub

lic h

ealth

inve

stig

atio

n an

d in

crea

sed

mic

robi

olog

ical

mon

itori

ng•

Cos

ts o

f med

ical

tre

atm

ent

for

affe

cted

peo

ple

• C

osts

for

time

lost

from

wor

k by

affe

cted

peo

ple

• Le

gal a

ctio

n fo

r ill

ness

cau

sed

by t

he o

utbr

eak?

Prev

entiv

e M

easu

res

• M

aint

enan

ce o

f int

egri

ty o

f sys

tem

bar

rier

s (p

ipes

, tan

ks).

•

Mai

ntai

n ac

cura

te r

ecor

ds.

• M

inim

isat

ion

of m

anur

e sp

rayi

ng n

ear

wat

er d

istr

ibut

ion

syst

em o

r co

ntro

l of r

un-o

ff.

• C

onsi

der

mon

itori

ng fo

r pr

otoz

oa (

in la

rge-

volu

me

sam

ples

: >

20 li

tres

) in

add

ition

to

colif

orm

s et

cet

era.

•

Test

ing

of w

ater

at

poin

t-of

-use

(cu

stom

er t

ap).

Ref

eren

ces

H. V

. Sm

ith a

nd J.

B. R

ose

(199

0). “

Wat

erbo

rne

Cry

ptos

pori

dios

is.”

Par

asito

logy

Tod

ay 6

(1):

8–1

2.

H. V

. Sm

ith e

t alia

(19

89).

“A

n ou

tbre

ak o

f wat

erbo

rne

cryp

tosp

orid

iosi

s ca

used

by

post

-tre

atm

ent

cont

amin

atio

n.”

Epi

dem

iol I

nfec

t 1

03

(3):

703

–715

. H

. V. S

mith

et a

lia (

1988

). “

[unt

itled

].” L

ance

t 2

: 14

84ff.

Loca

tion

and

Dat

eSa

ltcoa

ts a

nd S

teve

nsto

n, S

outh

Ayr

shir

e, S

cotla

nd.

Mar

ch–A

pril

1988

.

1 In fa

ct, o

nly

low

er S

altc

oats

was

ser

ved

by G

reen

head

Tre

atm

ent W

orks

, whi

le t

he a

ppro

xim

atel

y 40

00 r

esid

ents

of u

pper

Sal

tcoa

ts r

ecei

ved

wat

er a

bstr

acte

d fr

om t

he li

ne b

efor

e th

e br

eak-

pres

sure

ta

nk, w

hich

was

rou

ted

thro

ugh

a di

ffere

nt W

orks

. 2 A

sep

arat

e su

pply

from

Mun

noch

res

ervo

ir w

as fu

lly t

reat

ed a

t G

reen

head

, and

was

dis

trib

uted

from

a s

epar

ate

(tre

ated

-wat

er)

stor

age

tank

. 3 T

he a

bsen

ce o

f cas

es in

indi

vidu

als

aged

9 t

o 20

is p

roba

bly

at le

ast

part

ly a

ttri

buta

ble

to a

less

er e

xpos

ure

(i.e.

low

er d

ose)

. H

owev

er t

here

wer

e no

cas

es a

ged

40 t

o 90

eith

er (

one

fem

ale

case

was

re

cord

ed a

s be

ing

in t

he 9

0-95

age

gro

up).

Thi

s m

ay b

e du

e to

the

diff

erin

g im

mun

e sy

stem

str

engt

hs.

4 Cas

es in

Ard

ross

an, I

rvin

e an

d W

est

Kilb

ride

, “ha

d co

nnec

tions

with

low

er S

altc

oats

.” T

his

tend

s to

indi

cate

‘pri

mar

y in

fect

ion’

due

to

drin

king

con

tam

inat

ed w

ater

aft

er t

rave

lling

to

the

area

as

bein

g so

mew

hat

mor

e pr

obab

le, r

athe

r th

an ‘s

econ

dary

infe

ctio

n’ (

due

to p

erso

n-to

-per

son

spre

ad –

incl

udin

g in

dire

ctly

by

the

so-c

alle

d ‘fa

ecal

-ora

l rou

te’).

How

ever

sec

onda

ry in

fect

ion

prob

ably

did

occ

ur

duri

ng t

he o

utbr

eak.

Tw

o ca

ses

wer

e re

cord

ed fo

r K

ilwin

ning

.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

1.

Agr

icul

ture

With

in C

atch

men

ts

25 –

28:

All

Serv

ice

Res

ervo

irs

and

Tank

s Fa

ct S

heet

s

29. P

ipel

ine

Rep

airs

and

Mai

nten

ance


77

Cas

e S

tud

y 5 –

In

app

rop

riat

e D

efi

nit

ion

of

Pe

rfo

rman

ce T

hre

sho

lds

Cau

seC

onta

min

atio

n of

Wat

er S

uppl

y Sy

stem

and

Tre

atm

ent

Failu

re.

Sour

ce o

f haz

ard:

envi

ronm

enta

l was

te o

r ag

ricu

ltura

l act

ivity

Haz

ard:

m

icro

bial

pat

hoge

nsLi

kelih

ood:

rare

In C

arro

ll C

ount

y ro

ughl

y 79

00 o

ut o

f 190

00 h

ouse

hold

s w

ere

conn

ecte

d to

the

Car

rollt

on t

own

publ

ic w

ater

sys

tem

, whi

ch d

raw

s w

ater

from

a r

iver

run

ning

thr

ough

pa

stur

es. T

he w

ater

und

erw

ent

conv

entio

nal t

reat

men

t (c

oagu

latio

n w

ith a

lum

, fl o

ccul

atio

n, s

edim

enta

tion,

rap

id s

and fi l

trat

ion,

chl

orin

atio

n).

Alth

ough

the

wat

er m

et a

ll re

gula

tory

req

uire

men

ts, i

t is

pro

babl

e th

at “

sub-

optim

al” fl o

ccul

atio

n an

d fi l

trat

ion

allo

wed

the

infe

ctio

n to

pas

s th

roug

h. T

he s

ub-o

ptim

al

cond

ition

s in

clud

ed:

rem

oval

of a

gita

tors

from

the

fl oc

cula

tors

; in

effi c

ient

mon

itori

ng a

nd c

ontr

ol o

f fi lt

ratio

n a

nd r

esta

rtin

g of

fi lte

rs w

ithou

t fi r

st b

ackw

ashi

ng.

The

con

tam

inat

ion

may

hav

e be

en in

itiat

ed b

y ca

ttle

foun

d w

ith lo

w-le

vel i

nfec

tions

in t

he w

ater

shed

or

by s

ewag

e ov

erfl o

w.

Indi

cato

rs o

f Haz

ard

Initi

ally,

a “

dram

atic

incr

ease

” in

gas

troe

nter

itis

amon

g Wes

t G

eorg

ia C

olle

ge s

tude

nts.

Ove

r th

e co

urse

of t

he o

utbr

eak

ther

e w

as a

2 t

o 5-

fold

incr

ease

in t

he in

cide

nce

of d

iarr

hoea

. “T

he p

reva

lenc

e of

illn

ess

was

sig

nifi c

antly

gre

ater

in p

atie

nts

usin

g th

e cit

y’s d

rinki

ng w

ater

, des

pite

com

preh

ensiv

e tr

eatm

ent,

com

pare

d w

ith a

pop

ulat

ion

usin

g un

trea

ted

wel

l wat

er.”

Mea

sure

d Le

vels

of H

azar

dO

ocys

ts w

ere

dete

cted

in 7

of 9

wat

er s

ampl

es, w

ith c

once

ntra

tions

ave

ragi

ng 0

.63

oocy

sts/

L (h

ighe

st v

alue

: 2.

2).

No

unus

ually

hig

h le

vels

of o

ocys

ts w

ere

dete

cted

in w

ater

com

ing

in t

o th

e dr

inki

ng w

ater

tre

atm

ent

plan

t.1 Nei

ther

wer

e th

ere

any

tran

sgre

ssio

ns o

f col

iform

or

turb

idity

leve

ls (

<1c

fu/1

00m

L2 an

d ≤

1NT

U3, r

espe

ctiv

ely)

, alth

ough

par

ticle

s up

to

100µ

m w

ere

foun

d. F

urth

erm

ore,

the

chl

orin

e re

sidu

al h

ad b

een

mai

ntai

ned

at 0

.5m

g/L

with

in t

he d

istr

ibut

ion

syst

em –

as

high

as

1.5m

g/L

at t

he t

reat

men

t pl

ant.

4

Effe

ctA

n es

timat

ed 1

3,00

0 pe

rson

s w

ere

affe

cted

in t

he o

utbr

eak,

yie

ldin

g an

‘ove

rall

atta

ck r

ate’

of 4

0%, b

eing

slig

htly

hig

her

for

fem

ales

. Cr

ypto

spor

idiu

m o

ocys

ts w

ere

iden

tifi e

d in

sto

ols

of 5

8/14

7 =

39%

of p

atie

nts

with

gas

troe

nter

itis

duri

ng t

he o

utbr

eak,

and

no

othe

r pa

thog

en d

etec

ted.

Liab

ility

• C

osts

of p

rovi

sion

of a

ltern

ativ

e w

ater

sup

plie

s?•

Cos

t of

Wat

er T

reat

men

t Pl

ant

upgr

ade?

• C

osts

of p

ublic

hea

lth in

vest

igat

ion?

• C

osts

of m

edic

al t

reat

men

t fo

r af

fect

ed p

eopl

e?•

Cos

ts fo

r tim

e lo

st fr

om w

ork

by a

ffect

ed p

eopl

e?•

Lega

l act

ion

for

illne

ss c

ause

d by

the

out

brea

k?

Prev

entiv

e M

easu

res

• In

itiat

e ca

tchm

ent

prot

ectio

n: e

.g. a

dopt

a b

uffe

r st

rip

arou

nd s

ensi

tive

area

s of

the

cat

chm

ent,

use

off-s

trea

m w

ater

ing

for

catt

le.

• Ve

rify

tre

atm

ent

stan

dard

s (e

.g. r

equi

re fi

ltere

d w

ater

tur

bidi

ty -

0.2N

TU

, con

tinuo

usly

mon

itore

d) a

nd/o

r up

grad

e tr

eatm

ent

plan

t (c

onsi

der

also

dis

infe

ctio

n w

ith

ozon

e or

UV,

in a

dditi

on t

o ch

lori

ne).

• C

heck

, ver

ify a

nd e

nfor

ce t

reat

men

t pr

otoc

ols.

• C

ontr

ol e

quip

men

t m

odifi

catio

ns.

• C

onsi

der

the

nece

ssity

of a

n al

tern

ativ

e w

ater

sou

rce.

• Is

sue

boil-

wat

er a

dvic

e if

an o

utbr

eak

occu

rs, a

nd s

et u

p de

dica

ted

info

rmat

ion

serv

ice

for

publ

ic a

nd m

edic

al p

ract

ition

ers.


78

Ref

eren

ces

H. V

. Sm

ith a

nd J.

B. R

ose

(199

0). “

Wat

erbo

rne

Cry

ptos

pori

dios

is.”

Par

asito

logy

Tod

ay 6

(1):

8–1

2.

J. B.

Ros

e (F

eb. 1

988)

. “O

ccur

renc

e an

d Si

gnifi

canc

e of

Cry

ptos

pori

dium

in W

ater

.” Jo

urna

l AW

WA

(R

esea

rch

& T

echn

olog

y)

53–5

8.

E. B

. Hay

es e

t alia

(25

May

, 198

9). “

Larg

e C

omm

unity

Out

brea

k of

Cry

ptos

pori

dios

is d

ue t

o C

onta

min

atio

n of

a F

ilter

ed P

ublic

Wat

er S

uppl

y.” N

ew E

ngla

nd Jo

urna

l of

Med

icin

e 320

: 13

72–1

376.

Loca

tion

and

Dat

eC

arro

llton

, Geo

rgia

, USA

. Ja

nuar

y-Fe

brua

ry 1

987.

1 Alth

ough

the

raw

riv

er w

ater

(5

sam

ples

) w

as fo

und

to b

e ne

gativ

e fo

r Cr

ypto

spor

idiu

m, t

wo

stre

ams

drai

ning

into

the

riv

er w

ere

posi

tive.

2 i.

e. n

egat

ive.

3 T

rans

gres

sion

s in

the

fi rs

t 3h

aft

er s

tart

-up

with

out

back

was

hing

wer

e su

bseq

uent

ly fo

und

to o

ccur

, pro

duci

ng t

urbi

ditie

s up

to

3.2N

TU

. 4 C

rypt

ospo

ridi

um o

ocys

ts a

re h

ighl

y re

sist

ant

to d

isin

fect

ion

with

chl

orin

e.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

1

– 9:

All

Cat

chm

ent-

rela

ted

Fact

She

ets

14

. WT

P R

elia

bilit

y

20. W

TP

Des

ign

Cap

abili

ty –

Mic

robi

olog

ical

Con

tam

inat

ion

22

. WT

P D

esig

n C

apab

ility

– T

urbi

dity

23

. Dis

infe

ctio

n Sy

stem

Rel

iabi

lity

24

. Dis

infe

ctio

n Sy

stem

Des

ign

Cap

abili

ty


79

Cas

e S

tud

y 6 –

Co

nta

min

ate

d G

rou

nd

wat

er

So

urc

eC

ause

Con

sum

ptio

n of

con

tam

inat

ed g

roun

dwat

er fr

om t

ube-

wel

ls.

Sour

ce o

f haz

ard:

natu

rally

occ

urri

ng, i

norg

anic

ars

enic

Haz

ard:

he

avy

met

alLi

kelih

ood:

likel

y1 a

t ‘lo

w’ c

once

ntra

tion

(<50

µg/L

), ra

re a

t >

300µ

g/L

arse

nic

conc

entr

atio

n

Tube

-wel

ls w

ere

inst

alle

d in

Ban

glad

esh

(larg

ely

by a

id w

orke

rs, b

egin

ning

in t

he 1

970’

s), i

n an

effo

rt t

o lo

wer

mor

bidi

ty a

nd m

orta

lity

from

gas

troi

ntes

tinal

dis

ease

as

soci

ated

with

sur

face

wat

er t

hat

is o

ften

mic

robi

olog

ical

ly c

onta

min

ated

. The

se w

ells

con

sist

of t

ubes

of 5

cm

dia

met

er t

hat

are

inse

rted

into

the

gro

und

at d

epth

s of

us

ually

less

tha

n 20

0 m

.T

he w

ater

from

mill

ions

of t

hese

wel

ls w

as n

ot t

este

d fo

r ar

seni

c, re

sulti

ng in

“th

e la

rges

t po

ison

ing

of a

pop

ulat

ion

in h

isto

ry.”

Thr

ee o

ut o

f fou

r tu

be-w

ells

are

pri

vate

ly

owne

d.

Indi

cato

rs o

f Haz

ard

Cha

ract

eris

tic a

rsen

ic-in

duce

d sk

in le

sion

s w

ere

iden

tifi e

d.

Mea

sure

d Le

vels

of H

azar

dH

igh

conc

entr

atio

ns o

f ars

enic

, bei

ng >

50µ

g/L

(the

max

imum

leve

l per

mitt

ed in

Ban

glad

esh)

, wer

e fo

und

in 3

5% o

f 2,0

22 w

ater

sam

ples

(co

veri

ng 4

1 of

42

affe

cted

di

stri

cts)

, and

8.4

% w

ere

abov

e 30

0µg/

L. T

he m

axim

um le

vel r

ecom

men

ded

by t

he W

orld

Hea

lth O

rgan

isat

ion

(WH

O)

is 1

0µg/

L. S

usta

ined

dri

nkin

g of

wat

er w

ith a

n ar

seni

c co

ncen

trat

ion

of 5

00µg

/L m

ay r

esul

t in

10%

mor

talit

y du

e to

ars

enic

-indu

ced

canc

er.

Effe

ctA

rsen

ic-in

duce

d sk

in le

sion

s be

gin

to s

how

up

afte

r ab

out

ten

year

s. A

t le

ast

100,

000

case

s (e

stim

ate)

hav

e oc

curr

ed.

Both

inte

rnal

can

cers

and

ski

n ca

ncer

may

be

caus

ed b

y in

gest

ion

of a

rsen

ic, w

ith t

ypic

al la

tenc

y pe

riod

s of

20

year

s. T

hus

it is

impo

rtan

t to

con

side

r th

e de

velo

pmen

t of

th

ese

dise

ases

man

y ye

ars

into

the

futu

re.

An

estim

ated

20

to 7

5 m

illio

n of

the

125

mill

ion

inha

bita

nts

are

curr

ently

at

risk

.

Liab

ility

• C

osts

of p

rovi

sion

of a

ltern

ativ

e w

ater

sup

plie

s•

Cos

t of

wat

er t

reat

men

t 2

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

osts

of m

edic

al t

reat

men

t an

d lo

st t

ime

for

affe

cted

peo

ple

• Le

gal a

ctio

n fo

r ill

ness

cau

sed

by t

he o

utbr

eak

Prev

entiv

e M

easu

res

• M

easu

re a

nd m

onito

r fo

r ar

seni

c (a

nd o

ther

hea

vy m

etal

s) –

und

erst

and

bett

er t

he s

patia

l dis

trib

utio

n of

con

tam

inat

ed g

roun

dwat

er.

• Lo

cate

alte

rnat

ive

sour

ces:

tre

ated

sur

face

wat

er, d

eepe

r tu

be-w

ells

, sha

llow

dug

wel

ls3

or r

ainw

ater

.•

Prov

ide

‘can

dle’

fi lte

rs o

r tr

eatm

ent

chem

ical

s, an

d se

t up

ded

icat

ed in

form

atio

n se

rvic

e fo

r pu

blic

and

med

ical

pra

ctiti

oner

s.

Ref

eren

ces

A. H

. Sm

ith e

t alia

(20

00).

“C

onta

min

atio

n of

dri

nkin

g-w

ater

by

arse

nic

in B

angl

ades

h: a

pub

lic h

ealth

em

erge

ncy.”

Bul

letin

of t

he W

orld

Hea

lth O

rgan

isat

ion

78

(9):

10

93–1

103.

Loca

tion

and

Dat

eBa

ngla

desh

(at

leas

t 42

of 6

4 di

stri

cts)

< 1

987–

pres

ent.

1 Sig

nifi c

ant

leve

ls o

f ars

enic

hav

e al

so b

een

dete

cted

in t

he g

roun

dwat

er o

f man

y ot

her

natio

ns, i

nclu

ding

Arg

entin

a, C

hile

, Chi

na, I

ndia

, Mex

ico,

Tai

wan

, Tha

iland

and

the

U.S

.A..

2 Ty

pica

lly t

empo

rary

mea

sure

s at

poi

nt o

f use

. 3 A

ccor

ding

to

geog

raph

ical

loca

tion.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

2.

Env

iron

men

tal H

azar

ds w

ithin

Cat

chm

ents


80

Cas

e S

tud

y 7 -

Gro

un

dw

ate

r C

on

tam

inat

ion

an

d F

ailu

re o

f D

isin

fect

ion

Sys

tem

Cau

seM

anur

e ru

n-of

f fro

m fa

rms

ente

red

the

grou

ndw

ater

.

Sour

ce o

f haz

ard

– m

anur

e ru

n-of

f fro

m fa

rm(s

)H

azar

d –

mic

robi

al p

atho

gens

Like

lihoo

d –

occa

sion

al (

e.g.

follo

win

g on

ce-in

-10-

year

s st

orm

eve

nt)

Dri

nkin

g w

ater

was

sup

plie

d to

a s

mal

l tow

n (p

op. ~

5000

) vi

a a

publ

ic s

uppl

y fr

om 3

dri

lled

wel

ls, e

ach

with

chl

orin

atio

n un

its. T

he w

ells

(es

p. W

ell #

5) w

ere

in

low

-lyin

g la

nd, s

urro

unde

d by

farm

s. D

espi

te c

omm

on d

etec

tion

of fa

ecal

col

iform

s an

d th

e is

suin

g of

man

y w

arni

ngs

from

the

reg

ulat

ory

body

ove

r th

e ye

ars,

no r

emed

ial a

ctio

n w

as t

aken

. O

n th

e co

ntra

ry, c

hlor

inat

ion

of W

ell #

7 w

as c

ease

d du

e to

cus

tom

er c

ompl

aint

s ab

out

the

chlo

rine

tas

te. S

ome

chlo

rine

-res

idua

l mon

itori

ng r

ecor

ds w

ere

also

foun

d to

be

fals

ifi ed

. “D

istr

ibut

ion

syst

em”

sam

ples

wer

e al

so o

ften

tak

en a

t th

e pl

ant,

and

thos

e th

at w

eren

’t of

ten

faile

d.

Indi

cato

rs o

f Haz

ard

A o

nce-

in-1

00-y

ears

sto

rm e

vent

occ

urre

d ar

ound

the

beg

inni

ng o

f the

out

brea

k, li

kely

exa

cerb

atin

g a

pre-

exis

ting

cont

amin

atio

n.1

Earl

y re

cogn

ition

of c

ases

of b

lood

y di

arrh

oea

and

seve

re a

bdom

inal

cra

mps

in s

choo

l chi

ldre

n an

d re

side

nts

of h

omes

for

the

elde

rly.

E.

col

i O15

7:H

7 w

as la

ter

isol

ated

in r

aw a

nd ‘t

reat

ed’ w

ater

from

Wel

l #5,

in s

tool

sam

ples

from

pat

ient

s an

d in

man

ure.

Mea

sure

d Le

vels

of H

azar

dC

olifo

rms

wer

e de

tect

ed in

Wel

l #5.

E. c

oli w

as d

etec

ted

in t

he d

istr

ibut

ion

syst

em a

t >

200c

fu/1

00m

L.

Effe

ctEs

cher

ichi

a co

li O

157:

H7

is a

str

ain

of E

. col

i tha

t pr

oduc

es t

oxin

s.

An

estim

ated

2,3

00 in

divi

dual

s de

velo

ped

gast

ro-in

test

inal

com

plai

nts,

of w

hom

~1,

286

wer

e lo

cals

, tho

ugh

only

1,3

46 c

ases

wer

e re

port

ed (

med

ian

age

29).

T

he c

rude

att

ack

rate

was

26.

4%, g

ener

ally

dec

reas

ing

with

age

. 39

rep

orte

d ca

ses

wer

e at

trib

uted

to

seco

ndar

y in

fect

ion.

65

pers

ons

wer

e ad

mitt

ed t

o ho

spita

l (m

edia

n ag

e 8)

. 27

of t

hese

dev

elop

ed H

aem

olyt

ic U

rem

ic S

yndr

ome,

HU

S (m

edia

n ag

e 4)

, but

onl

y 17

(63

%)

exhi

bite

d th

e ‘ty

pica

l’ bl

oody

dia

rrho

ea.

HU

S ty

pica

lly a

ffect

s up

to

10%

of p

atie

nts

with

an

ente

roha

emor

rhag

ic E

. col

i (EH

EC)

infe

ctio

n, w

ith a

3 t

o 5%

cas

e-fa

talit

y ra

te. T

he m

edia

n ag

e of

tho

se w

ith

HU

S w

as 4

. In

thi

s in

stan

ce 7

peo

ple

ultim

atel

y di

ed d

ue t

o th

e ou

tbre

ak, a

ll fe

mal

es, o

ne c

hild

. O

f the

se 3

wer

e at

trib

uted

to

E. c

oli O

157:

H7

and

2 to

Cam

pylo

bact

er je

juni

. Fi

ve o

r si

x ha

d H

US.

Man

y of

the

illn

esse

s w

ere

prob

ably

due

to

Cryp

tosp

orid

ium

sp.

or

Gia

rdia

sp.

, tho

ugh

they

wer

e no

t de

tect

ed.

Liab

ility

• C

osts

of d

econ

tam

inat

ion

and

tem

pora

ry fi

ltrat

ion

syst

em (

> $

12 m

illio

n)•

Cos

t of

per

man

ent

trea

tmen

t so

lutio

n (e

quip

men

t, tr

aini

ng, a

uditi

ng)

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

osts

of m

edic

al t

reat

men

t an

d lo

st t

ime

for

affe

cted

peo

ple

• Le

gal a

ctio

n fo

r ill

ness

cau

sed

by t

he o

utbr

eak

($4

mill

ion

in le

gal c

osts

and

$17

mill

ion

in c

ompe

nsat

ion

paid

by

insu

rer(

s) [

insu

ranc

e pr

emiu

ms

have

now

ri

sen]

, rem

aind

er w

ill b

e pa

id b

y go

vern

men

t)


81

1 The

vie

w h

as b

een

put

forw

ard

by s

ome

expe

rts

that

if t

he s

torm

eve

nt h

ad n

ot o

ccur

red,

the

n it

is s

till l

ikel

y th

at t

here

wou

ld h

ave

been

som

e in

fect

ion

of m

embe

rs o

f the

com

mun

ity a

nd v

isito

rs

drin

king

the

wat

er w

ith E

. col

i O15

7:H

7, b

ut in

far

few

er n

umbe

rs.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

1. A

gric

ultu

re w

ithin

Cat

chm

ents

2. E

nvir

onm

enta

l Haz

ards

with

in C

atch

men

ts23

. Dis

infe

ctio

n Sy

stem

Rel

iabi

lity

24. D

isin

fect

ion

Syst

em D

esig

n C

apab

ility

Prev

entiv

e M

easu

res

• In

stal

l cat

chdr

ains

and

mai

ntai

n a

land

buf

fer

to r

educ

e ru

n-of

f infl

ow

and

to

give

mor

e tim

e to

res

pond

.•

Ensu

re a

dequ

ate

wel

l con

stru

ctio

n (e

.g. c

oncr

ete

linin

g of

bor

e ho

le).

• Fo

llow

reg

ulat

ions

.•

Ensu

re a

dequ

ate

staf

f tra

inin

g an

d un

ders

tand

ing

by s

taff

of p

roce

ss a

nd is

sues

.•

Inst

all U

V/c

hlor

ine

disi

nfec

tion

with

on-

line

resi

dual

ana

lyse

r.•

Act

on

adve

rse

mic

robi

al m

onito

ring

res

ults

, inc

ludi

ng n

otifi

catio

n of

all

rele

vant

aut

hori

ties.

• Tr

eat “

grou

nd w

ater

und

er t

he infl u

ence

of s

urfa

ce w

ater

” as

if it

wer

e su

rfac

e w

ater

.•

Turn

-off

syst

em if

ove

rwhe

lmed

.•

Issu

e ‘b

oil-w

ater

’ adv

isor

y, an

d se

t up

ded

icat

ed in

form

atio

n se

rvic

e fo

r pu

blic

and

med

ical

pra

ctiti

oner

s.

Ref

eren

ces

O’C

onno

r D

R. 2

002.

Rep

ort

of t

he W

alke

rton

Inqu

iry.

Par

t I a

nd II

. The

Att

orne

y G

ener

al o

f Ont

ario

, Tor

onto

, The

Wal

kert

on In

quir

y.L.

Sm

ith, B

. Ste

ele

and

J. Br

unto

n (1

Nov

. 200

0).

Cou

rt t

rans

crip

ts: T

he W

alke

rton

Inqu

iry

to In

quir

e in

to t

he W

alke

rton

Wat

er T

rage

dy. V

ol. X

. [d

ownl

oade

d fr

om h

ttp:

//ww

w.ts

crip

t.com

/]A

non.

(31

May

200

1). “

E. c

oli d

eath

tol

l clim

bs t

o se

ven.

” C

BC T

oron

to.

[dow

nloa

ded

from

htt

p://w

ww

.toro

nto.

cbc.

ca/fe

atur

e/w

alke

rton

/sev

en.h

tml]

WH

O (

July,

199

6). “

Esch

eric

hia

coli

O15

7:H

7.”

WH

O fa

ct s

heet

N 1

25.

BGO

SHU

(O

ctob

er, 2

000)

. The

Inve

stig

ativ

e R

epor

t of

the

Wal

kert

on O

utbr

eak

of W

ater

born

e G

astr

oent

eriti

s, M

ay–J

une

2000

.

Loca

tion

and

Dat

eW

alke

rton

, Ont

ario

, Can

ada.

May

, 200

0.


82

Cas

e S

tud

y 8 -

Co

nta

min

atio

n o

f a

Re

serv

oir

an

d C

atch

me

nt

Cau

seC

onta

min

atio

n of

sew

age

into

the

dis

trib

utio

n sy

stem

.

Sour

ce o

f haz

ard:

faec

es (

cat)

Haz

ard:

m

icro

bial

pat

hoge

nsLi

kelih

ood:

rare

(T

his

para

site

is a

lso

carr

ied

by o

ther

mam

mal

s, su

ch a

s sh

eep

and

bird

s)

The

Hum

pbac

k re

serv

oir

is o

ne o

f tw

o m

ain

rese

rvoi

rs s

ervi

cing

the

Gre

ater

Vic

tori

a ar

ea in

Bri

tish

Col

umbi

a. T

he m

unic

ipal

dis

trib

utio

n sy

stem

was

sup

plie

d w

ith

unfi l

tere

d, d

isin

fect

ed w

ater

from

tw

o ch

lora

min

atio

n pl

ants

dra

win

g w

ater

from

the

se t

wo

rese

rvoi

rs, s

ervi

ng a

tot

al o

f app

roxi

mat

ely

292,

000

resi

dent

s.

The

Hum

pbac

k R

eser

voir

was

iden

tifi e

d as

the

mos

t lik

ely

sour

ce o

f Tox

opla

sma

gond

ii oo

cyst

s w

hich

wer

e re

spon

sibl

e fo

r an

out

brea

k la

stin

g m

ore

than

6 m

onth

s. It

is

susp

ecte

d th

at t

he fa

eces

of d

omes

tic c

ats

(Fel

is ca

tus)

, fer

al c

ats

or w

ild c

ats

(i.e.

cou

gars

, Fel

is co

ncol

or)

ente

red

the

rese

rvoi

r or

its

feed

er s

trea

ms.

Indi

cato

rs o

f Haz

ard

15 in

divi

dual

s w

ere

iden

tifi e

d as

hav

ing

acut

e to

xopl

asm

osis

ove

r th

e fi r

st 7

9 da

ys o

f 199

5, c

ompa

red

with

1 t

o 4

case

s an

nual

ly in

the

pre

viou

s 4

year

s.

Con

curr

ently

a r

etin

al s

peci

alis

t ad

vise

d au

thor

ities

of t

he s

udde

n ap

pear

ance

of 7

cas

es o

f acq

uire

d to

xopl

asm

osis

ret

initi

s, w

hen

he c

ould

not

rem

embe

r a

case

in h

is

prac

tice

in t

he p

rece

ding

5 y

ears

.

Mea

sure

d Le

vels

of H

azar

dA

t th

e tim

e of

the

inve

stig

atio

n T.

gon

dii h

ad n

ever

bee

n is

olat

ed fr

om w

ater

, how

ever

stu

dies

wer

e be

ing

cond

ucte

d to

att

empt

thi

s, de

spite

the

fact

tha

t w

ater

sam

ples

w

ere

not

colle

cted

unt

il th

e w

ater

was

“st

rong

ly c

onsi

dere

d” t

he s

ourc

e, a

t w

hich

tim

e th

e ou

tbre

ak w

as o

ver.

Fo

ur o

f sev

en d

omes

tic/fe

ral c

ats

capt

ured

in t

he w

ater

shed

tes

ted

posi

tive

to T

oxop

lasm

a in

fect

ion.

Effe

ctBe

twee

n 1

Janu

ary

1995

and

6 S

epte

mbe

r 19

95, 1

10 a

cute

cas

es o

f T. g

ondi

i inf

ectio

n w

ere

iden

tifi e

d in

the

Gre

ater

Vic

tori

a ar

ea.

Of t

hese

, 42

infe

cted

wom

en a

nd 1

1 ne

wbo

rns

wer

e id

entifi

ed

in a

pre

gnan

cy-r

elat

ed s

cree

ning

pro

gram

. T

he t

rue

tota

l was

pro

babl

y si

gnifi

cant

ly g

reat

er, a

s m

ost

case

s w

ere

asym

ptom

atic

(pr

esen

ted

no o

bser

vabl

e sy

mpt

oms)

.

Liab

ility

• C

osts

of p

rovi

sion

of a

ltern

ativ

e w

ater

sup

plie

s•

Cos

t of

pos

sibl

e w

ater

tre

atm

ent

upgr

ade

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

osts

of m

edic

al t

reat

men

t fo

r af

fect

ed p

eopl

e•

Cos

ts fo

r tim

e lo

st fr

om w

ork

by a

ffect

ed p

eopl

e•

Lega

l act

ion

for

illne

ss c

ause

d by

the

out

brea

k

Prev

entiv

e M

easu

res

Prev

ent

acce

ss t

o th

e re

serv

oir

and

infl o

win

g st

ream

s by

pot

entia

l car

rier

s of

Tox

opla

sma

gond

ii (e

.g. c

ats)

.En

sure

mon

itori

ng o

f ‘at

ris

k’ g

roup

s, su

ch a

s pr

egna

nt w

omen

, rep

ortin

g of

any

sus

pect

ed o

utbr

eaks

(un

usua

lly h

igh

num

ber

of c

ases

) an

d sw

itchi

ng t

o al

tern

ativ

e w

ater

so

urce

if n

eces

sary

.In

stal

l fi lt

ratio

n pl

ant

(nei

ther

pri

mar

y ch

lora

min

atio

n no

r ch

lori

natio

n w

ould

be

suffi

cien

t).

It m

ay b

e he

lpfu

l to

mon

itor

wat

er fo

r ‘in

dica

tor

orga

nism

s’.


83

Ref

eren

ces

The

Bri

tish

Col

umbi

a Tox

opla

smos

is T

eam

: W. R

. Bow

ie e

t alia

(19

95).

“Pr

elim

inar

y R

epor

t O

utbr

eak

of T

oxop

lasm

osis

Ass

ocia

ted

with

Mun

icip

al D

rink

ing W

ater

–

Briti

sh C

olum

bia.”

Can

ada

Com

mun

icab

le D

isea

se R

epor

t 2

1(1

8):

161–

164.

J.

J. Ara

min

i et a

lia (

Apr

il 19

99).

“Po

tent

ial c

onta

min

atio

n of

dri

nkin

g w

ater

with

Tox

opla

sma

gond

ii oo

cyst

s.” E

pide

mio

l. In

fect

. 12

2(2

): 3

05–3

15.

Loca

tion

and

Dat

eG

reat

er V

icto

ria,

Briti

sh C

olum

bia,

Can

ada.

199

5.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

2. E

nvir

onm

enta

l Haz

ards

with

in C

atch

men

ts20

. WT

P D

esig

n C

apab

ility

– M

icro

biol

ogic

al C

onta

min

atio

n22

. WT

P D

esig

n C

apab

ility

– T

urbi

dity

24. D

isin

fect

ion

Syst

em -

Des

ign

Cap

abili

ty


84

Cas

e S

tud

y 9 -

Co

nta

min

atio

n o

f R

ese

rvo

ir a

nd

Dis

infe

ctio

n S

yste

m R

eli

abil

ity

/ F

ailu

reC

ause

Con

tam

inat

ion

of R

eser

voir

and

Dis

infe

ctio

n Fa

ilure

.

Sour

ce o

f haz

ard:

envi

ronm

enta

l/agr

icul

tura

l/oth

er (

lives

tock

)H

azar

d:

mic

robi

al p

atho

gens

Like

lihoo

d:

lik

ely

A v

illag

e w

as s

ervi

ced

by it

s ow

n ‘p

riva

te’ s

uppl

y, dr

awn

from

a r

eser

voir

hol

ding

wat

er t

hat

was

ori

gina

lly a

bstr

acte

d fr

om a

gro

undw

ater

sup

ply.

The

wat

er s

uppl

y w

as

foun

d to

be

“irr

egul

arly

” ch

lori

nate

d.

It is

tho

ught

tha

t th

e re

serv

oir

has

beco

me

cont

amin

ated

as

a re

sult

of li

vest

ock

graz

ing

in t

he a

rea,

and

that

thi

s co

ntam

inat

ion

pass

ed t

hrou

gh t

he s

yste

m d

ue t

o in

adeq

uate

tre

atm

ent.

A “

stro

ng”

asso

ciat

ion

of t

he o

utbr

eak

with

the

wat

er s

uppl

y w

as d

eter

min

ed.

Indi

cato

rs o

f Haz

ard

Cas

es o

f ill

heal

th (

patie

nts

exhi

bitin

g sy

mpt

oms

of g

iard

iasi

s).

Mea

sure

d Le

vels

of H

azar

d3

cyst

s pe

r lit

re o

f Gia

rdia

lam

blia

wer

e fo

und

in w

ater

from

a r

eser

voir

sup

plyi

ng w

ater

to

the

villa

ge.

Effe

ctA

n ou

tbre

ak o

f gia

rdia

sis,

affe

ctin

g on

ly r

esid

ents

of a

sin

gle

villa

ge, l

aste

d 17

5 da

ys.

A t

otal

of 3

1 ca

ses

wer

e re

port

ed, a

lthou

gh n

one

requ

ired

hos

pita

lisat

ion.

The

sto

ols

of fi

ve p

atie

nts

wer

e co

nfi r

med

to

cont

ain

Gia

rdia

lam

blia

.

Liab

ility

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

ost

of p

ossi

ble

wat

er t

reat

men

t up

grad

e•

Cos

ts o

f med

ical

tre

atm

ent

for

affe

cted

peo

ple

• C

osts

for

time

lost

from

wor

k by

affe

cted

peo

ple

• Le

gal a

ctio

n fo

r ill

ness

cau

sed

by t

he o

utbr

eak?

Prev

entiv

e M

easu

res

• M

aint

enan

ce o

f bar

rier

s lim

iting

acc

ess

to w

ater

sup

ply

syst

em a

nd t

he a

dapt

atio

n of

buf

fer

stri

ps a

roun

d th

e bo

unda

ry o

f the

res

ervo

ir.•

Rel

iabl

e di

sinf

ectio

n (e

.g. w

ith c

ontin

uous

res

idua

l mon

itori

ng)

acco

rdin

g to

wri

tten

pro

cedu

res,

com

plyi

ng w

ith r

egul

atio

ns.

• In

stal

latio

n of

fi ltr

atio

n pl

ant.

N

ote:

Mon

itori

ng fo

r G

. lam

blia

is p

roba

bly

not

prac

ticab

le fo

r a

sing

le s

mal

l rur

al c

omm

unity

(th

ough

it m

ay b

e po

ssib

le a

t th

e re

serv

oir)

.

Ref

eren

ces

C. F

urta

do e

t alia

(19

98).

“O

utbr

eaks

of w

ater

born

e in

fect

ious

inte

stin

al d

isea

se [

IID]

in E

ngla

nd a

nd W

ales

, 199

2-5.

” E

pide

mio

l. In

fect

. 12

1:

109–

119.

Loca

tion

and

Dat

eW

est

Mid

land

s, U

K.

Nov

embe

r 19

91.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

1. A

gric

ultu

re w

ithin

Cat

chm

ents

12. C

onta

min

ated

Infl o

w in

to R

eser

voir

s23

. Dis

infe

ctio

n Sy

stem

Rel

iabi

lity

24. D

isin

fect

ion

Syst

em D

esig

n C

apab

ility


85

Cas

e S

tud

y 10 -

Co

nta

min

atio

n o

f W

ate

r S

up

ply

fro

m U

nd

ete

rmin

ed

Po

int

Cau

seW

ater

born

e cr

ypto

spor

idio

sis

asso

ciat

ed w

ith a

bor

ehol

e su

pply.

Sour

ce o

f haz

ard:

unkn

own

(pos

sibl

y in

here

nt t

o bo

reho

le w

ater

)H

azar

d:

mic

robi

al p

atho

gens

Like

lihoo

d:

ra

re

An

unid

entifi

ed

heal

th a

utho

rity

cov

ered

a d

istr

ict

with

a p

opul

atio

n of

abo

ut 4

60,0

00, c

once

ntra

ted

in o

ne m

ajor

tow

n (p

op. 1

35,0

00)

and

two

othe

r ad

jace

nt t

owns

(c

ombi

ned

pop.

200

,000

). T

he d

istr

ict

was

sup

plie

d by

tw

o w

ater

com

pani

es.

In t

he N

orth

Eas

tern

hal

f one

com

pany

sup

plie

d tr

eate

d su

rfac

e w

ater

abs

trac

ted

from

lo

cal r

iver

s. In

the

Sou

th W

este

rn h

alf t

he o

ther

com

pany

dre

w w

ater

from

tw

o so

urce

s: a

pai

r of

bor

ehol

es (

supe

rchl

orin

ated

, par

tially

dec

hlor

inat

ed, b

ut n

ot fi

ltere

d)

and,

by

a la

rge

rive

r, an

othe

r bo

reho

le a

nd w

ell (

rapi

dly fi l

tere

d an

d ch

lori

nate

d).

An

outb

reak

occ

urre

d th

at w

as e

pide

mio

logi

cally

link

ed t

o th

e su

pply

of t

he s

econ

d w

ater

com

pany

, sup

plyi

ng t

he S

outh

Wes

tern

are

a. H

ydro

geol

ogis

ts c

lass

ifi ed

the

th

eore

tical

ris

k of

hyd

raul

ic c

onne

ctio

n w

ith t

he r

iver

as

unlik

ely.

Con

tam

inat

ion

of t

he c

over

ed s

ervi

ce r

eser

voir

s al

so s

eem

ed im

prob

able

, and

no

stru

ctur

al d

efec

ts

wer

e fo

und.

It

was

con

side

red

impo

ssib

le fo

r an

y of

the

bur

st w

ater

mai

n ev

ents

or

mai

nten

ance

wor

k t

o ha

ve a

ffect

ed a

suffi c

ient

ly w

ide

area

to

acco

unt

for

the

outb

reak

.

Indi

cato

rs o

f Haz

ard

In A

pril

1993

, 13

case

s of

cry

ptos

pori

dios

is w

ere

diag

nose

d in

5 d

ays

by a

sin

gle

publ

ic h

ealth

labo

rato

ry (

the

typi

cal o

ccur

renc

e w

as le

ss t

han

10 c

ases

per

mon

th).

11

of

the

patie

nts

lived

with

in ~

3km

of e

ach

othe

r.

It w

as c

alcu

late

d th

at h

ouse

hold

s re

ceiv

ing

mai

ns w

ater

from

the

sec

ond

publ

ic s

uppl

y w

ere

15 t

imes

mor

e lik

ely

to b

e af

fect

ed t

han

near

by h

ouse

hold

s re

ceiv

ing

wat

er

from

oth

er s

ourc

es.

A d

ose-

resp

onse

rel

atio

nshi

p be

twee

n w

ater

con

sum

ptio

n an

d ill

ness

was

als

o es

tabl

ishe

d.

Mea

sure

d Le

vels

of H

azar

dVe

ry lo

w c

once

ntra

tions

of C

rypt

ospo

ridiu

m o

ocys

ts w

ere

dete

cted

in t

he t

own

wat

er s

uppl

y on

four

occ

asio

ns, s

ever

al w

eeks

aft

er t

he o

utbr

eak

– th

ese

wer

e th

ough

t to

be

too

low

to

cons

titut

e a

publ

ic h

ealth

haz

ard

at t

hat

time.

R

outin

e m

onito

ring

of t

he w

ater

exi

ting

the

trea

tmen

t pl

ant,

incl

udin

g du

ring

the

out

brea

k pe

riod

, did

not

iden

tify

any

oocy

sts.

Effe

ct64

cas

es o

f cry

ptos

pori

dios

is w

ere

diag

nose

d in

the

per

iod

1 A

pril

to 3

1 M

ay 1

993,

40

of w

hom

wer

e co

nfi r

med

pos

itive

for

Cryp

tosp

orid

ium

ooc

ysts

in t

heir

(lo

ose)

st

ools

. Fo

ur o

f the

pat

ient

s re

quir

ed a

dmis

sion

to

hosp

ital.

Liab

ility

• C

ost

of d

rain

ing

the

mai

n se

rvic

e re

serv

oir

and

exam

inin

g st

ruct

ure

and

insp

ectio

n of

the

silt

(no

ooc

ysts

foun

d) o

n tw

o oc

casi

ons

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

ost

of p

ossi

ble

trea

tmen

t pl

ant

upgr

ade

• C

osts

of m

edic

al t

reat

men

t an

d tim

e lo

st fr

om w

ork

for

affe

cted

peo

ple

• Le

gal a

ctio

n fo

r ill

ness

cau

sed

by t

he o

utbr

eak

Prev

entiv

e M

easu

res

“The

failu

re t

o de

tect

any

cle

ar m

echa

nism

for

cont

amin

atio

n of

the

tow

n w

ater

sys

tem

aft

er a

bstr

actio

n ra

ises

the

pos

sibi

lity

that

the

bor

ehol

e w

ater

con

tain

ed

oocy

sts.”

It

is w

idel

y as

sum

ed t

hat

bore

hole

wat

er d

oes

not

requ

ire fi l

trat

ion,

how

ever

thi

s pr

emis

e m

ay b

e fl a

wed

.


86

Ref

eren

ces

D. M

orga

n et

alia

(23

June

199

5). “

Wat

erbo

rne

cryp

tosp

orid

iosi

s as

soci

ated

with

a b

oreh

ole

supp

ly.”

Com

mun

icab

le D

isea

se R

epor

t [C

DR

] R

evie

w 5

(7):

R93

–R97

. Se

e al

so:

C. M

. Han

cock

et a

lia (

Mar

ch 1

998)

. “C

rypt

ospo

ridi

um a

nd G

iard

ia in

US

grou

ndw

ater

.” Jo

urna

l of t

he A

mer

ican

Wat

er W

orks

Ass

ocia

tion

[AW

WA

] 9

0(3

):

58ff.

Loca

tion

and

Dat

eU

.K. [

exac

t lo

catio

n no

t di

sclo

sed]

. Apr

il–M

ay 1

993.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

2. E

nvir

onm

enta

l Haz

ards

With

in C

atch

men

ts20

. WT

P C

apab

ility

– M

icro

biol

ogic

al C

onta

min

atio

n (P

atho

gens

)24

. Dis

infe

ctio

n Sy

stem

Des

ign

Cap

abili

ty


87

Cas

e S

tud

y 11 -

Bre

ach

ing

of

Mai

ns

Cau

seSe

wag

e co

ntam

inat

ion

of d

rink

ing

wat

er.

Sour

ce o

f haz

ard:

sew

age

(hum

an)

Haz

ard:

m

icro

bial

pat

hoge

nsLi

kelih

ood:

a w

ater

mai

n br

eak

near

a s

ewag

e sp

ill w

ould

be

unus

ual,

but

not

rare

An

outb

reak

of g

astr

oint

estin

al il

lnes

s w

as a

ttri

bute

d to

sew

age

cont

amin

atio

n of

the

dri

nkin

g w

ater

sup

ply

to a

tow

n. T

he c

onta

min

atio

n w

as r

elat

ed t

o th

e in

vest

igat

ions

of s

ewag

e di

scha

rge

into

a r

oad

gully

. A

wat

er m

ain

was

dam

aged

dur

ing

the

inve

stig

atio

n, le

adin

g to

a lo

ss o

f pre

ssur

e, a

nd a

bout

thr

ee h

ours

aft

er t

hat

sew

age

solid

s w

ere

notic

ed in

the

tre

nch

surr

ound

ing

the

wat

er m

ains

. The

sup

ply

was

sub

sequ

ently

cut

off

and

boil

wat

er a

dvic

e is

sued

to

the

affe

cted

res

iden

ts.

Indi

cato

rs o

f Haz

ard

Obs

erva

tion

of s

ewag

e so

lids

in w

ater

mai

n tr

ench

. H

igh

rate

s of

abs

ente

eism

in lo

catio

ns w

hose

wat

er s

uppl

y is

der

ived

from

the

cat

chm

ent

in w

hich

the

con

tam

inat

ion

occu

rred

.

Mea

sure

d Le

vels

of H

azar

dN

o m

icro

bial

con

tam

inan

ts w

ere

iden

tifi e

d in

pat

ient

s’ s

tool

s. M

icro

biol

ogic

al in

vest

igat

ions

wer

e co

ntin

uing

.

Effe

ct87

5 ho

useh

olds

wer

e af

fect

ed b

y th

e di

srup

tion

to t

he w

ater

sup

ply,

due

to t

he n

eed

to s

hut

dow

n th

e da

mag

ed m

ain

to r

epai

r it.

Alth

ough

the

sup

ply

was

re

stor

ed a

fter

onl

y 11

hou

rs, t

he s

ewer

rep

airs

too

k 3

days

, and

the

boi

l wat

er n

otic

e re

mai

ned

in e

ffect

for

one

wee

k.

In a

nea

rby

area

, who

se w

ater

was

der

ived

from

the

cat

chm

ent

in w

hich

the

spi

llage

occ

urre

d (n

ot n

eces

sari

ly s

erve

d by

the

bro

ken

wat

er m

ain)

, an

outb

reak

su

spec

ted

to b

e vi

ral g

astr

oent

eriti

s oc

curr

ed.

How

ever

the

pat

hoge

n w

as n

ot b

e id

entifi

ed.

(It

is n

ot u

ncom

mon

for

the

iden

tity

of t

he p

atho

gen

to r

emai

n un

know

n.)

83

of 5

24 c

hild

ren

wer

e ab

sent

from

tw

o sc

hool

s, co

mpa

red

to a

nor

mal

dai

ly r

ate

of a

bout

30

abse

ntee

s. E

pide

mio

logi

cal i

nves

tigat

ions

to

dete

rmin

e th

e pr

obab

ility

of a

link

to

the

spill

age

wer

e co

ntin

uing

.

Liab

ility

• C

osts

of s

uper

chlo

rina

tion

and fl u

shin

g of

sys

tem

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

osts

of m

edic

al t

reat

men

t fo

r af

fect

ed p

eopl

e•

Cos

ts fo

r tim

e lo

st fr

om w

ork

by a

ffect

ed p

eopl

e•

Publ

ic r

elat

ions

cos

ts t

o co

mpa

ny

Prev

entiv

e M

easu

res

• C

are

in u

nder

taki

ng w

orks

in t

he v

icin

ity o

f wat

er m

ains

(pa

rtic

ular

ly d

iggi

ng),

and

effe

ctiv

e no

tifi c

atio

n of

rel

evan

t pa

rtie

s of

the

loca

tion

of t

hese

pip

es.

• Pr

iori

ty c

onta

inm

ent

of s

ewag

e sp

ills

and

repa

ir o

f sew

er.

Ref

eren

ces

Ano

n. (

4 D

ecem

ber

1998

). “

Sew

age

cont

amin

atio

n of

dri

nkin

g w

ater

in B

olto

n.”

CD

R W

eekl

y 8

(49)

: 43

1.

Loca

tion

and

Dat

eBo

lton,

Lan

cash

ire,

Eng

land

, UK

. N

ovem

ber

1998

.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

6. W

aste

Man

agem

ent

/ Was

tew

ater

Fac

ilitie

s With

in C

atch

men

ts29

. Pip

elin

e R

epai

rs a

nd M

aint

enan

ce


88

Cas

e S

tud

y 12 -

Co

nta

min

atio

n o

f W

ate

r R

eti

cula

tio

n S

yste

mC

ause

Faec

al c

onta

min

atio

n of

dri

nkin

g w

ater

.

Sour

ce o

f haz

ard:

ingr

ess

of c

onta

min

atio

nH

azar

d:

mic

robi

al p

atho

gens

Like

lihoo

d:

po

or d

isin

fect

ion

prac

tices

in s

mal

l com

mun

ities

are

com

mon

At

a fu

nctio

n he

ld in

a r

ural

Abo

rigi

nal t

own,

an

outb

reak

of g

astr

oint

estin

al il

lnes

s oc

curr

ed, w

hich

was

att

ribu

ted

to t

he c

omm

unity

pot

able

wat

er s

uppl

y. T

his

wat

er

supp

ly h

ad a

his

tory

of n

on-c

ompl

ianc

e w

ith N

atio

nal H

ealth

and

Med

ical

Res

earc

h C

ounc

il (N

HM

RC

) gu

idel

ines

. In

Mar

ch o

f 199

8 (t

he m

onth

bef

ore

the

outb

reak

), th

e he

alth

dep

artm

ent

inst

ruct

ed t

he w

ater

sup

ply

syst

em t

o be

dos

ed w

ith c

hlor

ine

(1.5

g/1,

000L

), ho

wev

er n

o re

cord

s w

ere

disc

over

ed c

onfi r

min

g th

at t

his

actio

n w

as a

ctua

lly u

nder

take

n. I

t w

as s

uspe

cted

tha

t st

agna

nt w

ater

in a

ret

icul

atio

n si

de-li

ne m

ay h

ave

been

har

bour

ing

the

sour

ce o

f the

con

tam

inat

ion.

Indi

cato

rs o

f Haz

ard

Sam

ples

tak

en in

the

2 m

onth

s pr

ior

to t

he o

utbr

eak

wer

e co

nsid

ered

una

ccep

tabl

y co

ntam

inat

ed.

The

non

-com

plia

nce

in M

arch

invo

lved

col

iform

cou

nts

from

sou

rce

and

retic

ulat

ion

wat

er s

ampl

es t

hat

wer

e 4

to 5

tim

es t

he a

ccep

tabl

e lim

it se

t by

the

NH

MR

C.

Sam

ples

tak

en in

Apr

il ag

ain

faile

d to

mee

t th

e gu

idel

ine

valu

es.

Seve

ral v

isito

rs t

o th

e to

wn

who

att

ende

d th

e fu

nctio

n pr

esen

ted

sym

ptom

s of

gas

troe

nter

itis

(dia

rrho

ea a

nd n

ause

a), t

he fi

rst

case

s be

ing

with

in 3

6 ho

urs

of t

he

susp

ecte

d tim

e of

infe

ctio

n.

Mea

sure

d Le

vels

of H

azar

dC

olifo

rm c

ount

s w

ere

up t

o 5

times

the

lim

it.

Effe

ctT

hirt

een

case

s of

gas

troe

nter

itis

wer

e id

entifi

ed,

with

11

of t

he p

atie

nts

bein

g vi

sito

rs t

o th

e co

mm

unity

and

2 b

eing

res

iden

ts. T

his

yiel

ds a

n at

tack

rat

e of

69%

(11

of

16)

for

visi

tors

to

the

com

mun

ity, w

hile

the

rat

e am

ong

resi

dent

s w

as m

uch

low

er a

nd o

nly

non-

Abo

rigi

nal r

esid

ents

rep

orte

d ill

ness

. Thu

s th

e po

tent

ial e

ffect

s of

an

exis

ting

cont

amin

atio

n m

ay h

ave

been

‘mas

ked’

by

imm

unity

dev

elop

ed o

ver

time

by lo

cals

.G

iven

tha

t on

e vi

sito

r ne

ither

ate

nor

dra

nk a

t th

e fu

nctio

n, it

cou

ld b

e ar

gued

tha

t th

e tr

ue a

ttac

k ra

te is

clo

ser

to 7

3%.

From

sto

ol s

peci

men

s ta

ken

from

7 v

isito

rs, t

wo

spec

imen

s w

ere

posi

tive

for

Smal

l Rou

nd-S

truc

ture

d V

irus

, SR

SV, (

or N

orw

alk-

like

viru

s, N

LV)

and

one

spec

imen

re

veal

ed C

ampy

loba

cter

jeju

ni, b

ut n

o ot

her

bact

eria

l pat

hoge

ns o

r ro

tavi

rus

wer

e id

entifi

ed.

Liab

ility

• C

osts

of s

uper

chlo

rina

tion

and fl u

shin

g of

sys

tem

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

osts

of m

edic

al t

reat

men

t fo

r af

fect

ed p

eopl

e•

Cos

ts fo

r tim

e lo

st fr

om w

ork

by a

ffect

ed p

eopl

e

Prev

entiv

e M

easu

res

• El

imin

atin

g de

ad z

ones

and

are

as o

f sta

gnan

t w

ater

in d

esig

n of

sys

tem

.•

Ensu

ring

ade

quat

e di

sinf

ectio

n, b

ased

on

guid

elin

es, r

egul

atio

ns a

nd b

acte

riol

ogic

al m

onito

ring

.•

Res

pond

to

outb

reak

s of

ill h

ealth

.

Ref

eren

ces

D. E

wal

d et

alia

(16

Mar

ch 2

000)

. “Po

ssib

le c

omm

unity

imm

unity

to

Smal

l Rou

nd-S

truc

ture

d V

irus

gas

troe

nter

itis

in a

rur

al A

bori

gina

l com

mun

ity.”

Com

mun

icab

le

Dis

ease

Inte

llige

nce

24

(3):

48–5

0.

Loca

tion

and

Dat

eC

entr

al A

ustr

alia

. Apr

il 19

98.


89

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

1 –

9: A

ll C

atch

men

t re

late

d Fa

ct S

heet

s14

. WT

P R

elia

bilit

y20

. WT

P D

esig

n C

apab

ility

– M

icro

biol

ogic

al C

onta

min

atio

n23

. Dis

infe

ctio

n Sy

stem

Rel

iabi

lity

24. D

isin

fect

ion

Syst

em D

esig

n C

apab

ility

35. S

tagn

ant W

ater

in P

ipel

ines


90

Cas

e S

tud

y 13 -

Co

nta

min

atio

n o

f W

ate

r S

up

ply

fro

m U

nk

no

wn

Po

int

Cau

sePr

obab

le c

onta

min

atio

n of

the

sou

rce

wat

er (

Lake

Mea

d re

serv

oir)

.

Sour

ce o

f haz

ard:

sew

age

or o

ther

was

teH

azar

d:

mic

robi

al p

atho

gens

Like

lihoo

d:

ra

re

Base

d on

epi

dem

iolo

gica

l evi

denc

e, d

rink

ing

tap

wat

er fr

om t

he c

omm

unity

sup

ply

was

foun

d to

be

the

maj

or r

isk

fact

or fo

r an

out

brea

k of

cry

ptos

pori

dios

is in

Las

Veg

as

in 1

994.

1 A

t th

is s

tage

it w

as t

oo la

te t

o is

sue

a bo

il-w

ater

adv

isor

y.

The

wat

er is

dra

wn

from

a m

ajor

res

ervo

ir o

n th

e da

mm

ed C

olor

ado

rive

r at

a d

epth

of 4

0m.

It is

con

side

red

“pri

stin

e” (

aver

age

infl u

ent

turb

idity

~0.

14N

TU

, pea

k of

0.

3NT

U2 ).

A t

reat

men

t pl

ant

serv

ing

800,

000

pers

ons

cons

iste

ntly

del

iver

ed w

ater

with

tur

bidi

ty <

0.2N

TU

.Tr

eatm

ent

was

by

dire

ct fi

ltrat

ion

with

ferr

ic c

hlor

ide

as p

rim

ary

coag

ulan

t, ra

dial

-fl ow

fl oc

cula

tion,

dua

l-med

ia fi

ltrat

ion

and

both

pre

- an

d po

st-c

hlor

inat

ion

(1.4

mg/

L re

sidu

al),

in a

fully

-aut

omat

ed a

nd c

ompu

teri

sed

faci

lity.

C

onta

min

atio

n w

as t

houg

ht p

ossi

ble

by e

ither

:•

trea

ted

was

tew

ater

dis

char

ge t

o th

e la

ke 1

0km

ups

trea

m o

f the

raw

wat

er in

take

(th

ough

fl ow

dyn

amic

s in

the

res

ervo

ir m

ade

this

dou

btfu

l);•

or s

ewag

e fr

om b

oats

moo

red

at a

nea

rby

mar

ina

and

from

a n

earb

y ba

thin

g be

ach

dow

nstr

eam

(th

ough

no

trea

tmen

t po

nd m

alfu

nctio

n or

bac

kup

was

do

cum

ente

d).

It w

as s

uspe

cted

tha

t th

e an

nual

des

trat

ifi ca

tion

and

turn

over

of t

he la

ke m

ay h

ave

cont

ribu

ted.

Pos

sibl

e tr

eatm

ent

defi c

ienc

ies

incl

uded

:•

pass

age

of o

ocys

ts t

hrou

gh t

he fi

lter

units

(es

peci

ally

dur

ing

the

‘rip

enin

g’ s

tage

, aft

er b

ackw

ash)

;•

recy

clin

g of

bac

kwas

h w

ater

to

the

head

of t

he p

lant

;•

or s

ome

(uni

dent

ifi ed

) cr

oss-

conn

ectio

n.

Indi

cato

rs o

f Haz

ard

The

num

ber

of c

ases

of c

rypt

ospo

ridi

osis

, a r

epor

tabl

e di

seas

e in

Nev

ada

sinc

e 19

92, i

ncre

ased

. It

was

fi rs

t re

cogn

ised

am

ong

pers

ons

infe

cted

with

HIV

, who

sho

w

mor

e se

vere

sym

ptom

s an

d w

hose

doc

tors

are

oft

en m

ore

know

ledg

eabl

e ab

out

the

dise

ase

and

its d

iagn

osis

.

Mea

sure

d Le

vels

of H

azar

dD

urin

g th

e ou

tbre

ak, a

ll w

ater

sam

ples

tak

en a

t th

e pl

ant

and

with

in t

he d

istr

ibut

ion

syst

em w

ere

nega

tive

for

Cryp

tosp

orid

ium

par

vum

. N

eith

er w

ere

othe

r w

ater

qua

lity

para

met

ers

elev

ated

out

side

gui

delin

e va

lues

. H

owev

er, f

ollo

win

g th

e ou

tbre

ak, f

or t

he p

erio

d Ju

ly 1

994

to F

ebru

ary

1996

, ave

rage

pre

sum

ptiv

e oo

cyst

cou

nts

in t

he r

aw w

ater

, bac

kwas

h an

d fi l

tere

d w

ater

wer

e,

resp

ectiv

ely,

11, 5

9 an

d <

1 pe

r 10

0L.

Effe

ctA

tot

al o

f 103

labo

rato

ry-c

onfi r

med

cas

es o

f cry

ptos

pori

dios

is w

ere

asso

ciat

ed w

ith t

he o

utbr

eak,

with

78

case

s oc

curr

ing

duri

ng t

he s

tudy

per

iod.

3

Of t

he 7

8 ca

ses,

63 w

ere

infe

cted

with

HIV

or A

IDS

(2 c

hild

ren)

. O

f the

rem

aini

ng 1

5 ca

ses

(11

child

ren)

, who

wer

e no

t in

fect

ed w

ith H

IV/A

IDS,

2 of

the

4 a

dults

wer

e un

derg

oing

imm

unos

uppr

essi

ve t

reat

men

t.

Ana

lysi

s of

mor

talit

y ra

tes

is c

ompl

icat

ed b

y th

e pr

esen

ce o

f man

y H

IV/A

IDS

infe

cted

pat

ient

s. H

owev

er, o

f the

78

case

s, 32

had

die

d by

end

June

199

4, 4

1 ha

d di

ed b

y en

d A

pril

1995

(1

child

), an

d at

leas

t 20

(al

l HIV

-infe

cted

) ha

d cr

ypto

spor

idio

sis

liste

d as

the

ir c

ause

of d

eath

.

Liab

ility

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

ost

of t

reat

men

t pl

ant

upgr

ade

• C

osts

for

med

ical

tre

atm

ent

and

time

lost

from

wor

k by

affe

cted

peo

ple

• Le

gal a

ctio

n fo

r ill

ness

cau

sed

by t

he o

utbr

eak


91

Prev

entiv

e M

easu

res

• R

equi

re a

cou

nt o

f ≤10

par

ticle

s (2

.5 t

o 15

0µm

) pe

r 1m

L•

Poly

mer

add

ition

to

back

was

h fr

om fi

lters

• M

ore

stri

ngen

t m

onito

ring

for

Cryp

tosp

orid

ium

.

Ref

eren

ces

S. T.

Gol

dste

in e

t alia

(1

Mar

ch 1

996)

. “C

rypt

ospo

ridi

osis

: An

Out

brea

k A

ssoc

iate

d w

ith D

rink

ing W

ater

Des

pite

Sta

te-o

f-the

-Art

Wat

er T

reat

men

t.” A

nnal

s of

Inte

rnal

M

edic

ine

124

(5)

459–

468.

H

. Sol

o-G

abri

ele

and

S. N

eum

eist

er (

Sept

. 199

6). “

US

outb

reak

s of

cry

ptos

pori

dios

is.”

Jour

nal o

f the

Am

eric

an W

ater

Wor

ks A

ssoc

iatio

n 8

8(9

): 7

6–86

.

Loca

tion

and

Dat

eC

lark

Cou

nty,

Las V

egas

, Nev

ada,

USA

. D

ec. 1

993

– Ju

ne 1

994.

1 Alth

ough

exp

ert

revi

ews

of t

his

stud

y su

ppor

ted

the fi n

ding

of t

ap w

ater

as

a m

ajor

ris

k fa

ctor

, som

e el

emen

ts o

f the

stu

dy w

ere

criti

cise

d.

2 Val

ues

for

the

peri

od Ja

nuar

y 19

93 t

o Ju

ne 1

995.

3

The

se fi

gure

s re

late

onl

y to

cas

es c

onfi r

med

as

cryp

tosp

orid

iosi

s by

isol

atio

n of

the

ooc

ysts

in t

he la

bora

tory

. “Ev

iden

ce s

ugge

sts

that

the

out

brea

k m

ay h

ave

exte

nded

into

the

gen

eral

com

mun

ity,”

mor

e th

an is

sug

gest

ed b

y th

e fi g

ures

.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

1 –

13: A

ll C

atch

men

ts a

nd R

eser

voir

rel

ated

Fac

t Sh

eets

14. W

TP

Rel

iabi

lity

20. W

TP

Des

ign

Cap

abili

ty –

Mic

robi

olog

ical

Con

tam

inat

ion

23. D

isin

fect

ion

Syst

em R

elia

bilit

y24

. Dis

infe

ctio

n Sy

stem

Des

ign

Cap

abili

ty


92

Cas

e S

tud

y 14 -

Acc

ide

nta

l A

dd

itio

n o

f E

xce

ss C

he

mic

alC

ause

Acc

iden

tal o

verfl

uor

idat

ion.

Sour

ce o

f haz

ard:

inad

equa

te c

ontr

ol m

easu

res

for

chem

ical

add

ition

Haz

ard:

fl u

orid

eLi

kelih

ood:

rare

1

A s

mal

l Ala

skan

vill

age

was

spl

it in

to t

wo

geog

raph

ical

ly d

istin

ct s

ectio

ns, w

ith e

ach

bein

g se

rved

by

thei

r ow

n w

ell a

nd p

ublic

wat

er s

yste

m. T

he w

ater

was

not

pip

ed t

o re

side

nts,

but

need

ed t

o be

man

ually

ret

riev

ed fr

om h

oldi

ng t

anks

. T

he w

ater

sys

tem

sup

plyi

ng o

ne o

f the

tw

o se

ctio

ns (

popu

latio

n 47

0) in

clud

ed a

6, 3

40 li

tre

hold

ing

tank

, tw

o 95

litr

e ch

emic

al v

ats

(for

chlo

rine

and

fl uo

ride

co

ncen

trat

es),

pum

ps a

nd le

vel c

ontr

ol in

stru

men

tatio

n.

The

req

uire

men

t to

sub

mit

mon

thly

fl uo

ride

rea

ding

s to

the

sta

te h

ad n

ot b

een

met

for

alm

ost

two

year

s. M

oreo

ver,

the

oper

ator

lack

ed fo

rmal

tra

inin

g an

d w

as u

nabl

e to

cor

rect

ly p

erfo

rm fl

uori

de t

ests

. H

igh

leve

ls o

f fl u

orid

e in

the

sys

tem

wer

e do

cum

ente

d in

Janu

ary

1991

(7.

3mg/

L) a

nd a

gain

in e

arly

Apr

il an

d ea

rly

May

199

2 (6

.5 a

nd 2

0mg/

L, r

espe

ctiv

ely)

. Aft

er t

he la

st

of t

hese

rep

orts

, loc

al h

ealth

offi

cial

s as

ked

the

wat

er-s

yste

m o

pera

tor

to d

rain

the

hol

ding

tan

k an

d un

plug

the

fl uo

ride

pum

p. H

owev

er o

n 26

May

199

2 th

e pu

mp

was

st

ill o

pera

ting.

M

ajor

ele

ctri

cal a

nd m

echa

nica

l def

ects

wer

e id

entifi

ed

in t

he w

ater

sys

tem

:•

the

cont

rol s

yste

m w

as u

nrel

iabl

e an

d di

d no

t co

nsis

tent

ly a

ctiv

ate

the

wat

er p

ump;

• th

e fl u

orid

e do

sing

pum

p ra

n fo

ur t

imes

fast

er t

han

expe

cted

and

(du

e to

inco

rrec

t w

irin

g) c

ould

be

oper

ated

inde

pend

ently

of t

he w

ater

pum

p; 2

• un

der

cert

ain

cond

ition

s, th

e fl u

orid

e co

ncen

trat

e (1

8,00

0mg/

L) c

ould

be

siph

oned

into

the

wel

l.3

A c

ase-

cont

rol s

tudy

impl

icat

ed t

his

syst

em in

an

outb

reak

of a

cute

fl uo

ride

poi

soni

ng, h

owev

er w

hich

of t

he t

wo

poss

ible

cau

ses

(iden

tifi e

d ab

ove)

wer

e re

spon

sibl

e co

uld

not

be d

eter

min

ed.

Indi

cato

rs o

f Haz

ard

Hig

h le

vels

of fl

uor

ide

in t

he s

yste

m w

ere

docu

men

ted.

The

reg

ulat

ory

requ

irem

ent

to s

ubm

it m

onth

ly fl

uori

de le

vels

was

not

com

plie

d w

ith.

Staf

f at

the

loca

l hea

lth c

linic

obs

erve

d th

at a

n ou

tbre

ak o

f acu

te g

astr

oint

estin

al il

lnes

s ha

d oc

curr

ed in

the

vill

age

and

that

, fur

ther

mor

e, m

any

resi

dent

s ha

d be

com

e ill

sh

ortly

aft

er d

rink

ing

wat

er fr

om t

hat

syst

em.4 T

his

led

to t

he w

ater

sys

tem

for

that

sec

tion

of t

he v

illag

e be

ing

turn

ed o

ff (2

3 M

ay 1

992)

.

Mea

sure

d Le

vels

of H

azar

dT

he fl

uori

de c

once

ntra

tions

of w

ater

sam

ples

tak

en fr

om t

he w

ell i

mpl

icat

ed in

the

out

brea

k w

ere

foun

d to

hav

e pe

aked

aro

und

the

time

of t

he o

utbr

eak:

fro

m 2

mg/

L (2

0 M

ay)

to 1

50m

g/L

(21

May

) ba

ck t

o 58

mg/

L (2

7 M

ay).

C

ase

patie

nts’

fl uo

ride

dos

es w

ere

estim

ated

as

rang

ing

betw

een

0.3

and

21m

g/kg

(bo

dy m

ass)

. A s

tron

g co

rrel

atio

n w

as y

ield

ed fr

om d

ose-

resp

onse

ana

lysi

s.

Effe

ctA

n es

timat

ed 2

96 in

divi

dual

s su

ffere

d fl u

orid

e po

ison

ing

(>50

% a

ttac

k ra

te),

char

acte

rise

d by

nau

sea,

vom

iting

, dia

rrho

ea, a

bdom

inal

pai

n an

d pa

raes

thes

ia (

~sk

in

irri

tatio

n).

One

indi

vidu

al, a

41-

year

-old

mal

e, d

ied.

He

had

suffe

red

24 h

ours

of i

ntra

ctab

le v

omiti

ng, d

urin

g w

hich

he

had

dran

k an

est

imat

ed 1

0 lit

res

of w

ater

in a

n at

tem

pt t

o re

mai

n hy

drat

ed.

His

onl

y kn

own

pre-

exis

ting

illne

ss w

as p

eptic

ulc

er d

isea

se.

Liab

ility

• C

osts

of fl

ush

ing

of s

yste

m•

Cos

ts o

f pro

visi

on o

f alte

rnat

ive

wat

er s

uppl

ies

• C

osts

of p

ublic

hea

lth in

vest

igat

ion

• C

osts

of m

edic

al t

reat

men

t fo

r af

fect

ed p

eopl

e•

Cos

ts fo

r tim

e lo

st fr

om w

ork

by a

ffect

ed p

eopl

e•

Lega

l act

ion

for

illne

ss c

ause

d by

the

out

brea

k –

the

wid

ow o

f the

dec

ease

d w

as t

akin

g le

gal a

ctio

n ag

ains

t th

e lo

cal H

ealth

Cor

pora

tion,

see

king

$3

mill

ion

(Car

ton

et

al 1

994)

for

bein

g ne

glig

ent

in n

ot w

arni

ng v

illag

ers

of t

he h

azar

d


93

Prev

entiv

e M

easu

res

• En

forc

e sa

tisfa

ctor

y ro

utin

e m

onito

ring

of fl

uor

ide

leve

ls (

incl

udin

g su

bmis

sion

to

regu

lato

ry b

odie

s) a

nd a

dequ

ate

oper

ator

tra

inin

g.•

Suffi

cien

t re

spon

se t

o de

tect

ion

of h

igh

conc

entr

atio

ns.

• U

pgra

de, m

aint

ain

and

veri

fy p

erfo

rman

ce o

f con

trol

sys

tem

(s),

and

clea

rly

iden

tify

plan

t ite

ms

with

labe

ls.

• C

ondu

ct a

Ris

k A

sses

smen

t or

Haz

ard

Ana

lysi

s.

Ref

eren

ces

L. R

. Pet

erse

n et

alia

(Ju

ne 1

988)

. “C

omm

unity

hea

lth e

ffect

s of

a m

unic

ipal

wat

er s

uppl

y hy

perfl

uor

idat

ion

acci

dent

.” A

mer

ican

Jour

nal o

f Pub

lic H

ealth

[A

m J

Publ

ic

Hea

lth]

78

(6):

711

–713

. B.

D. G

essn

er e

t alia

(13

Janu

ary

1994

). “

Acu

te F

luor

ide

Pois

onin

g fr

om a

Pub

lic W

ater

Sys

tem

.” N

ew E

ngla

nd Jo

urna

l of M

edic

ine

33

0(2

): 9

5–99

. R

. Car

ton

& T

he T

ruth

Abo

ut F

luor

ide,

Inc.

(Oct

ober

199

4). “

Mid

dlet

own

Mar

ylan

d La

test

City

to

Rec

eive

Tox

ic S

pill

of F

luor

ide

in t

heir

Dri

nkin

g Wat

er.”

The

Tow

nsen

d Le

tter

for

Doc

tors

. [d

ownl

oade

d fr

om h

ttp:

//ww

w.fl

uori

deal

ert.o

rg/a

ccid

ents

.htm

]

Loca

tion

and

Dat

eH

oope

r Ba

y, A

lask

a. 2

1–23

May

199

2.

1 “

The

saf

ety

of t

his

prac

tice

[fl u

orid

atio

n] is

sup

port

ed b

y th

e ex

trem

e ra

rity

of i

ncid

ents

of o

verfl

uor

idat

ion.

” (

Ges

sner

, 199

4)2 T

he e

leva

ted fl u

orid

e co

ncen

trat

ion

mea

sure

d (1

50m

g/L)

cou

ld h

ave

been

rea

ched

with

in a

bout

26

hour

s in

thi

s w

ay.

3 The

ele

vate

d co

ncen

trat

ion

coul

d ha

ve b

een

reac

hed

in a

mat

ter

of m

inut

es b

y em

ptyi

ng a

full fl u

orid

e va

t.

4 The

med

ian

inte

rval

bet

wee

n co

nsum

ptio

n of

wat

er a

nd o

nset

of s

ympt

oms

was

7 m

inut

es (

rang

ing

form

<1

to 1

50 m

inut

es).

Thi

s co

ntra

sts

with

the

incu

batio

n pe

riod

s re

leva

nt t

o di

scus

sion

of

wat

erbo

rne

outb

reak

s of

mic

robi

olog

ical

ori

gin.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

14

. WT

P R

elia

bilit

y


94

Cas

e S

tud

y 15 -

Ch

em

ical

Le

ach

ing

of

Pip

e M

ate

rial

sC

ause

Lead

leac

hing

from

sol

der

used

in d

omes

tic c

oppe

r pl

umbi

ng.

Sour

ce o

f haz

ard:

lead

sol

der

Haz

ard:

le

adLi

kelih

ood:

com

mon

“The

use

of l

ead

sold

er a

s a

join

ting

com

poun

d fo

r co

pper

pip

ewor

k of

dom

estic

wat

er s

uppl

y sy

stem

s w

as b

anne

d by

the

intr

oduc

tion

of W

ater

Byl

aws

in 1

987”

in

Scot

land

, due

to

stud

ies

show

ing

that

lead

cou

ld le

ach

into

wat

er b

y th

e pr

oces

s of

gal

vani

c co

rros

ion.

Thi

s is

of c

once

rn b

ecau

se e

ven

appa

rent

ly lo

w c

once

ntra

tions

of

lead

can

hav

e a

harm

ful e

ffect

ove

r tim

e du

e to

bio

accu

mul

atio

n in

sof

t tis

sues

. W

hen

it w

as d

isco

vere

d th

at t

he b

an w

as n

ot b

eing

obs

erve

d, 6

61 r

ando

mly

sel

ecte

d ho

uses

(bu

ilt a

fter

Janu

ary

1997

) w

ere

surv

eyed

. Thi

s in

volv

ed t

estin

g ‘g

rab

sam

ples

’ fr

om t

he h

ot a

nd c

old

bath

room

tap

s as

wel

l as

the

kitc

hen

cold

wat

er t

ap.

Indi

cato

rs o

f Haz

ard

“It

was

ass

umed

tha

t th

e le

ad s

olde

r ba

n w

as b

eing

obs

erve

d un

til e

vide

nce

to t

he c

ontr

ary

was

pro

vide

d by

an

inci

dent

in 1

999

invo

lvin

g a

new

hou

se [

…]”

in w

hich

ex

cess

ive

lead

leve

ls w

ere

foun

d. A

you

ng c

hild

and

the

chi

ld’s

fath

er h

ad b

een

suffe

ring

a r

ange

of u

nexp

lain

ed s

ympt

oms “

for

som

e m

onth

s” –

“no

n-sp

ecifi

c,” b

ut

“com

patib

le w

ith lo

w-le

vel l

ead

toxi

city

” –

and

wer

e la

ter

foun

d to

hav

e “m

ildly

ele

vate

d” b

lood

lead

leve

ls.

Mea

sure

d Le

vels

of H

azar

d99

of t

he 6

61 h

ouse

s su

rvey

ed (

15%

) yi

elde

d at

leas

t on

e1 sam

ple

with

an

“exc

ess”

lead

con

tent

(≥

5µg/

L) in

dica

ting

the

pres

ence

of s

olde

r. P

ropo

rtio

ns w

ere

high

er fo

r th

e ne

wes

t ho

uses

(bu

ilt in

200

0):

abou

t 32

%2 o

f the

se h

ouse

s ha

d at

leas

t on

e sa

mpl

e w

ith a

n “e

xces

s” le

ad c

onte

nt. T

his

prob

ably

refl

ect

s a

redu

ctio

n in

det

ecta

ble

lead

leac

hate

as

time

pass

es, r

athe

r th

an a

n in

crea

se in

the

use

of l

ead

sold

er.

59 h

ouse

s (8

.9%

) ha

d at

leas

t on

e sa

mpl

e w

ith a

lead

con

cent

ratio

n ab

ove

the

“Ulti

mat

e N

ew W

ater

Reg

ulat

ion

Valu

e” o

f 10µ

g/L3.

33

(5.0

%)

wer

e ab

ove

the

“Int

erim

N

ew W

ater

Reg

ulat

ion

Valu

e” o

f 25µ

g/L.

12

hous

es (

1.8%

) ha

d at

leas

t on

e sa

mpl

e w

ith le

ad le

vels

abo

ve t

he “

Exis

ting W

ater

Reg

ulat

ion

Valu

e” (

at t

he t

ime

of w

ritin

g) o

f 50

µg/L

. T

he m

axim

um le

vel r

ecor

ded

in t

he s

urve

y w

as 2

57.3

µg/L

.4

Effe

ctTw

o ca

ses

of il

l hea

lth la

stin

g fo

r so

me

mon

ths

(see

Indi

cato

rs o

f Haz

ard)

wer

e di

rect

ly a

ttri

bute

d to

the

use

of l

ead

sold

er in

dom

estic

plu

mbi

ng.

Due

to

the

wid

espr

ead

natu

re o

f the

con

trav

entio

n of

the

Wat

er B

ylaw

s in

res

pect

of t

he u

se o

f lea

d so

lder

(af

fect

ing

an e

stim

ated

36,

000

to 7

5,36

0 ho

uses

sin

ce 1

987)

, as

wel

l as

the

slow

pro

gres

sion

of t

he il

lnes

s, it

is li

kely

tha

t ot

her

case

s re

mai

ned

unre

port

ed a

nd/o

r un

diag

nose

d.

Liab

ility

• C

osts

of r

epla

cing

plu

mbi

ng•

Cos

ts o

f inv

estig

atio

n•

Cos

ts o

f med

ical

tre

atm

ent

for

affe

cted

peo

ple

• C

osts

for

time

lost

from

wor

k by

affe

cted

peo

ple?

• Le

gal a

ctio

n fo

r ill

ness

?

Prev

entiv

e M

easu

res

• Ed

ucat

ion

of p

ublic

, tra

desp

eopl

e an

d au

thor

ities

(e.

g. in

spec

tors

).•

Mor

e in

spec

tions

.•

Enfo

rcin

g of

pen

altie

s fo

r in

frin

gem

ent

of B

ylaw

s.•

The

fi ne

impo

sed

for

viol

atio

n ha

s be

en in

crea

sed,

and

the

tim

e lim

it fo

r pr

osec

utio

n w

ould

be

exte

nded

. •

A t

otal

ban

on

lead

sol

der

(for

all a

pplic

atio

ns)

may

be

inst

itute

d.


95

Ref

eren

ces

Scot

tish

Cen

tre

for

Infe

ctio

n an

d En

viro

nmen

tal H

ealth

(O

ctob

er 2

000)

. Sc

ottis

h N

ew H

omes

Lea

d Su

rvey

. St

age

1.

Scot

tish

Exec

utiv

e (2

7 N

ovem

ber

2000

). “

Exec

utiv

e ta

kes

actio

n on

lead

in w

ater

.” P

ress

Rel

ease

s SE

3051

/200

0.

[do

wnl

oade

d fr

om h

ttp:

//ww

w.s

cotla

nd.g

ov.u

k/ne

ws/

2000

/11/

se30

51.a

sp]

Loca

tion

and

Dat

eSc

otla

nd, U

K.

1987

–200

0.

1 In 6

0 of

the

99

hous

es, o

nly

one

of t

he t

hree

sam

ples

indi

cate

d le

ad w

as p

rese

nt (

9% o

f the

tot

al s

et o

f 661

).

2 Ad

hoc

surv

eys

by L

ocal

Aut

hori

ties

of n

ew h

ouse

s si

nce

1999

giv

e an

ave

rage

pro

port

ion

of 3

8% (

not

stan

dard

ised

).

3 Ado

pted

from

the

Wor

ld H

ealth

Org

anis

atio

n, d

ue t

o co

me

into

forc

e in

the

yea

r 20

13 (

by E

C d

irec

tive)

. 4 T

his

com

pare

s to

a m

axim

um o

f 3,7

60µg

/L r

ecor

ded

by a

Loc

al A

utho

rity

in t

he a

d ho

c sa

mpl

ing

refe

rred

to.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

31

. Pip

e M

ater

ials

, Pri

vate

Mai

ns a

nd C

usto

mer

Plu

m


96

Cas

e S

tud

y 16 -

In

ten

tio

nal

Bre

ach

ing

of

Mai

ns

(Sab

ota

ge)

Cau

seIn

terf

eren

ce w

ith t

he d

istr

ibut

ion

pipe

line

by v

anda

ls.

Sour

ce o

f haz

ard:

sabo

tage

Haz

ard:

no

n-su

pply

of w

ater

1

Like

lihoo

d:

ra

re

Met

row

ater

is a

pub

lic w

ater

and

was

tew

ater

util

ity c

ompa

ny s

uppl

ying

wat

er in

the

Auc

klan

d is

thm

us.

Earl

y on

e Sp

ring

mor

ning

, van

dals

(ap

pare

ntly

) us

ed a

hac

ksaw

to

cut

thro

ugh

gask

ets

in t

he m

ain

wat

er d

istr

ibut

ion

pipe

line2 , a

t M

t. R

oski

ll. T

he t

elem

etry

sys

tem

had

al

so b

een

atta

cked

and

no

long

er fu

nctio

ned

(it w

as “

dest

roye

d”).

W

ater

was

“gu

shin

g” fr

om t

he m

ain

whe

n it

was

dis

cove

red,

at

arou

nd 8

am. T

he m

ain

was

sw

itche

d of

f in

orde

r fo

r re

pair

wor

k to

be

carr

ied

out,

whi

ch w

as t

houg

ht t

o be

com

plet

e at

abo

ut 1

0am

. A

t th

is t

ime

the

wat

er w

as t

urne

d ba

ck o

n. H

owev

er it

was

qui

ckly

evi

dent

tha

t “th

e da

mag

e w

as w

orse

tha

n fi r

st t

houg

ht,”

as t

he m

ain

pipe

con

sequ

ently

bur

st, c

ausi

ng

min

or fl

oodi

ng.

Thi

s ne

cess

itate

d th

e w

ater

to

be s

witc

hed

off a

t th

e re

serv

oir

feed

ing

the

pum

p st

atio

n, b

efor

e a

digg

er c

ould

beg

in r

epai

rs.

Indi

cato

rs o

f Haz

ard

Cus

tom

ers

com

plai

ned

to t

he w

ater

com

pany

tha

t th

ey h

ad n

o w

ater

. H

owev

er t

he t

elem

etry

sys

tem

did

not

ale

rt o

pera

tors

.

Mea

sure

d Le

vels

of H

azar

dA

ccor

ding

to

the

Met

row

ater

spo

kesw

oman

, the

per

petr

ator

s ha

d “d

one

a fa

ir b

it of

dam

age

and

gone

at

it w

ith a

fair

bit

of in

tent

, bec

ause

it’s

not

easy

to

dam

age

pipe

s of

tha

t si

ze.”

Effe

ctT

he w

ater

sup

ply

to “

mor

e th

an 1

,000

hou

seho

lds”

was

dis

rupt

ed.

From

ear

ly M

onda

y m

orni

ng u

ntil

perh

aps

mid

day

ther

e w

as n

o w

ater

del

iver

ed.

The

reaf

ter

wat

er w

as d

eliv

ered

from

sur

roun

ding

are

as, a

lbei

t at

red

uced

pre

ssur

e, u

ntil

repa

irs

wer

e co

mpl

eted

. (R

epai

rs w

ere

due

to b

e co

mpl

ete

by 4

pm o

n th

e da

y of

the

inci

dent

, but

in fa

ct c

ontin

ued

over

to

(at

leas

t) t

he n

ext

day.)

The

wat

er w

as s

aid

to b

e su

ffi ci

ent

for “

sani

tary

pur

pose

s.”

Met

row

ater

’s in

itial

est

imat

es o

f the

cos

ts fo

r co

mpl

ete

repa

ir w

ere

“in

the

thou

sand

s” (

25 S

epte

mbe

r 20

00).

T

he s

ite’s

carp

ark

as w

ell a

s ne

ighb

ouri

ng p

riva

te p

rope

rtie

s w

ere fl o

oded

dur

ing

the

inci

dent

and

fi refi g

hter

s w

ere

calle

d to

hel

p pu

mp

out

the

wat

er. T

his

was

as

soci

ated

with

a r

isk

to t

he w

ater

qua

lity,

in t

hat

the

pollu

ted

seep

age

coul

d pa

ss b

ack

into

the

mai

n, d

ue t

o th

e lo

w p

ress

ure

afte

r th

e w

ater

was

cut

off,

and

on

into

the

di

stri

butio

n ne

twor

k.

Liab

ility

• C

osts

of p

rovi

sion

of a

ltern

ativ

e w

ater

sup

plie

s•

Cos

ts o

f rep

airs

(“t

hous

ands

” of

dol

lars

)•

Cos

ts o

f im

prov

emen

ts t

o se

curi

ty

Prev

entiv

e M

easu

res

• C

ontr

ol a

cces

s to

mai

n pi

pelin

e (e

.g. g

uard

s pa

trol

ling

area

, bar

bed-

wir

e fe

nces

, CC

TV

).•

Find

out

und

erly

ing

reas

on fo

r va

ndal

ism

and

tak

e m

easu

res

to d

isco

urag

e it

from

occ

urri

ng a

gain

.•

Inst

all b

ette

r te

lem

etry

to

dete

ct lo

ss o

f wat

er p

ress

ure

or r

educ

tion

in fl

ow (

such

as

may

be

due

to a

sig

nifi c

ant

brea

ch),

and

that

wou

ld a

lso

aler

t th

e op

erat

or t

o se

lf-fa

ilure

.


97

Ref

eren

ces

E. B

inni

ng (

25 S

epte

mbe

r 20

00).

“Va

ndal

s su

spec

ted

of w

ater

sab

otag

e.”

INL

New

spap

ers.

[d

ownl

oade

d fr

om h

ttp:

//ww

w.s

tuff.

co.n

z/in

l/pri

nt/0

,110

3,39

3213

a150

0,FF

.htm

l]J.

Brow

n (2

5 Se

ptem

ber

2000

). “

Vand

alis

m t

urns

off

wat

er t

o th

ousa

nds.”

The

New

Zea

land

Her

ald.

[d

ownl

oade

d fr

om h

ttp:

//nzh

eral

d.co

.nz/

stor

ypri

nt.c

fm?s

tory

ID=

1527

04]

Loca

tion

and

Dat

eM

t. R

oski

ll &

Mt.

Eden

(ab

out

5km

from

Auc

klan

d), N

ew Z

eala

nd.

24 S

epte

mbe

r 20

00. 3

1 Thi

s co

uld fi r

st im

pact

suc

h cr

itica

l org

anis

atio

ns a

s m

edic

al a

nd fi

refi g

htin

g fa

cilit

ies,

if th

ey d

id n

ot h

ave

acce

ss t

o al

tern

ativ

e su

pplie

s. In

gen

eral

, res

iden

ts w

ould

fi rs

t su

ffer

only

‘inc

onve

nien

ce’ a

t fi r

st, a

lthou

gh t

he g

ravi

ty o

f the

situ

atio

n w

ould

wor

sen

as t

ime

pass

es. T

here

may

be

som

e pu

blic

rel

atio

ns p

robl

ems

for

the

wat

er s

uppl

y or

gani

satio

n.

2 Br

own’

s re

port

sta

tes

that

the

pip

e w

as a

ttac

ked,

with

out

refe

rrin

g to

gas

kets

. M

ost

prob

ably

the

dam

age

was

to

the fl a

nges

of t

wo

pipe

s an

d th

e ga

sket

bet

wee

n th

em.

3 Acc

ordi

ng t

o Bi

nnin

g’s r

epor

t, th

e in

cide

nt o

ccur

red

on 2

5 Se

ptem

ber

2000

.

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

3. H

uman

Acc

ess

to C

atch

men

ts28

. Ext

erna

l Con

tam

inat

ion

of S

ervi

ce R

eser

voir

s an

d Ta

nks

29. P

ipel

ine

Rep

airs

and

Mai

nten

ance

32. H

igh

Flow

in P

ipel

ines


98

Cas

e S

tud

y 17 -

Nat

ura

lly

Occ

urr

ing

Co

nta

min

ant

Cau

seG

row

th o

f nox

ious

and

/or

toxi

c pl

ant

life

in r

eser

voir

s.

Sour

ce o

f haz

ard:

vari

ous

spec

ies

of a

lgae

Haz

ard:

ta

ste

and

odou

r an

d/or

hep

atot

oxin

sLi

kelih

ood:

occu

rs r

egul

arly,

dep

endi

ng o

n lo

cal h

ydro

logi

cal a

nd m

eteo

rolo

gica

l con

ditio

ns

In 1

991/

1992

, aro

und

1,00

0 km

of t

he D

arlin

g R

iver

(N

ew S

outh

Wal

es)

expe

rien

ced

alga

l blo

oms.

Thi

s re

ceiv

ed w

ide-

spre

ad c

over

age

in t

he m

edia

, with

the

res

ult

that

bo

th t

he p

ublic

and

the

aut

hori

ties

beca

me

mor

e se

nsiti

ve t

o th

e oc

curr

ence

of a

lgal

blo

oms

in w

ater

sto

rage

s.

An

unus

ually

larg

e nu

mbe

r of

blo

oms

in Q

ueen

slan

d w

ere

repo

rted

to

the

Wat

er R

esou

rces

Com

mis

sion

(W

RC

) fr

om A

ugus

t 19

91 –

Sep

tem

ber

1992

. Whi

le n

ot

disc

ount

ing

the

effe

ct o

f inc

reas

ed p

ublic

ity, t

he p

rim

ary

fact

ors

cont

ribu

ting

to t

he b

loom

s w

ere

belie

ved

to b

e th

e m

odes

t w

et s

easo

n, w

hich

was

follo

wed

by

an

unus

ually

pro

long

ed p

erio

d of

abo

ve-a

vera

ge t

empe

ratu

res.

T

he m

ajor

ity o

f the

rep

orte

d bl

oom

s oc

curr

ed in

Sou

th E

ast

Que

ensl

and,

alth

ough

som

e bl

oom

s in

tro

pica

l are

as w

ere

also

rep

orte

d1 (no

t co

vere

d in

the

follo

win

g).

Mos

t of

the

rep

orte

d bl

oom

s re

sulte

d in

a c

losu

re o

f the

wat

er s

tora

ge a

rea

to a

cces

s by

the

pub

lic, e

spec

ially

for

recr

eatio

nal u

se. A

t se

ven

stor

ages

2 the

pro

blem

was

co

nsid

ered

to

be s

uffi c

ient

ly s

ever

e as

to

war

rant

sw

itchi

ng t

o an

alte

rnat

ive

wat

er s

uppl

y. A

few

sou

rces

rem

aine

d in

use

des

pite

tas

te a

nd o

dour

com

plai

nts.

Indi

cato

rs o

f Haz

ard

The

gen

eral

pro

gres

sion

is t

hat

alga

e is

fi rs

t id

entifi

ed

as p

rese

nt b

y ei

ther

vis

ual i

nspe

ctio

n, r

outin

e m

onito

ring

(ce

ll co

unt

or c

hlor

ophy

ll-a)

3 , or

cust

omer

com

plai

nts

(rel

atin

g to

tas

te a

nd/o

r od

our)

. If

not

alre

ady

carr

ied

out,

cell

coun

ts w

ould

usu

ally

be

carr

ied

out,

follo

wed

by

iden

tifi c

atio

n of

the

gen

us (

and

poss

ible

spe

cies

and

va

riet

y) o

f the

alg

a or

alg

ae.

Fina

lly, d

epen

ding

on

the

outc

omes

of t

hese

tes

ts, t

he a

lgae

may

be

sent

to

a la

bora

tory

for

toxi

city

ana

lysi

s.

Mea

sure

d Le

vels

of H

azar

dA

t M

aroo

n D

am M

icroc

ystis

and

Ana

baen

a w

ere

iden

tifi e

d, w

ith c

ount

s ra

ngin

g fr

om 1

03 to

105 (

mos

t 2,

000

to 2

5,00

0) a

nd fr

om 1

0 to

1,0

00 c

ells

/mL,

res

pect

ivel

y. S

ome

Botr

ycoc

cus

was

als

o fo

und.

Tox

icity

tes

t re

sults

wer

e in

cons

iste

nt:

test

ing

at t

he e

nd o

f Apr

il sh

owed

the

scu

m t

o be

hep

atot

oxic

in t

he t

wo

area

s sa

mpl

ed, w

hile

sev

en

days

late

r, in

ear

ly M

ay, o

nly

one

of t

he a

reas

ret

urne

d a

toxi

c re

sult.

At

Lesl

ie D

am M

icroc

ystis

was

iden

tifi e

d at

con

cent

ratio

ns r

angi

ng fr

om 1

,000

to

8,00

0 ce

lls/m

L –

alth

ough

mos

t co

unts

wer

e be

twee

n 1,

000

and

7,50

0 ce

lls/m

L. T

he

alga

e w

as c

lass

ed a

s “no

n to

xic,”

des

pite

a “

slig

ht a

bnor

mal

ity in

one

mou

se li

ver.”

T

hese

blu

e-gr

een

alga

e co

loni

es w

ere

even

ly d

istr

ibut

ed t

hrou

ghou

t th

e da

m t

o de

pths

gre

ater

tha

n 10

m a

nd p

ersi

sted

for

mor

e th

an t

hree

mon

ths.

At

othe

r st

orag

es A

naba

enop

sis, O

scilla

toria

and

Cyli

ndro

sper

mop

sis g

ener

a w

ere

iden

tifi e

d. A

t so

me

stor

ages

no

iden

tifi c

atio

n w

as r

ecor

ded.

T

he h

ighe

st c

ount

was

on

the

orde

r of

106 c

ells

/mL

(Ana

baen

a fl o

s-aq

uae

and

circin

alis

– to

xici

ty n

ot t

este

d). A

gain

, at

som

e st

orag

es n

o ce

ll co

unts

wer

e re

port

ed.


99

Effe

ctM

aroo

n D

am w

as c

lose

d fo

r re

crea

tion

and

loca

ls w

arne

d. A

lthou

gh t

here

is n

o to

wn

wat

er s

uppl

y ab

stra

cted

from

thi

s da

m, l

ocal

pro

pert

ies

and

a ne

arby

Edu

catio

n D

epar

tmen

t ca

mp

used

wat

er d

irec

tly fr

om t

he r

eser

voir.

The

Wat

er R

esou

rces

Com

mis

sion

(W

RC

) ho

uses

wer

e eq

uipp

ed w

ith c

arbo

n fi l

ters

, and

so

they

wer

e ab

le

to c

ontin

ue t

o us

e th

e w

ater

. H

owev

er w

ater

had

to

be t

ruck

ed in

for

bath

ing,

cook

ing

and

drin

king

at

the

child

ren’

s ca

mp.

Oth

er la

ndho

lder

s w

ere

advi

sed

to u

se

alte

rnat

ive

supp

lies

or e

lse

trea

t th

e w

ater

.

The

tow

n of

War

wic

k re

ceiv

ed w

ater

sup

plie

s fr

om t

wo

dam

s, an

d so

whe

n th

e Le

slie

Dam

sup

ply

was

tur

ned

off,

wat

er w

as t

aken

from

Con

nolly

Dam

. U

nfor

tuna

tely

th

e C

onno

lly D

am p

ipel

ine

was

not

of s

uffi c

ient

cap

acity

to

mee

t th

e fu

ll de

man

d an

d so

som

e re

stri

ctio

ns w

ere

nece

ssar

y. H

owev

er t

he im

pact

was

per

ceiv

ed t

o be

“r

elat

ivel

y sm

all”

. R

osen

thal

Shi

re w

as a

ble

to s

witc

h to

gro

undw

ater

. D

owns

trea

m s

ampl

es w

ere

free

of a

lgae

, and

so

this

wat

er c

ontin

ued

to b

e us

ed fo

r st

ock

wat

erin

g. T

he im

pact

was

als

o le

ssen

ed d

ue t

o th

e lo

w ir

riga

tion

dem

and

at

that

tim

e of

yea

r (A

utum

n-W

inte

r).

Just

aft

er r

eope

ning

the

dam

, bef

ore

East

er, t

here

was

a s

pell

of w

arm

, cle

ar w

eath

er a

nd t

he t

herm

oclin

e w

as r

emov

ed, w

hich

was

link

ed t

o th

e su

dden

exp

losi

on in

cel

l co

unts

tha

t w

as o

bser

ved.

Thi

s fo

rced

the

rec

losu

re o

f the

are

a al

ong

with

the

rem

oval

of c

ampe

rs, w

hich

rec

eive

d na

tiona

l med

ia a

tten

tion.

As

men

tione

d, s

even

loca

tions

sw

itche

d to

an

alte

rnat

ive

supp

ly, m

any

wer

e cl

osed

for

recr

eatio

nal u

se a

nd s

ome

cust

omer

s co

mpl

aine

d of

tas

te a

nd o

dour

. “T

he b

igge

st im

pact

was

pos

sibl

y th

e ge

nera

l pub

lic c

once

rn t

hat

so m

any

dam

s in

the

are

a w

ere

clos

ed s

imul

tane

ousl

y, an

d th

e un

cert

aint

y re

gard

ing

safe

ty o

f dri

nkin

g w

ater

”.

Liab

ility

• C

ost

of t

ruck

ing

in w

ater

or

orga

nisi

ng o

ther

sup

ply.

•

The

WR

C in

stal

led

a pi

lot

plan

t in

corp

orat

ing

gran

ular

act

ivat

ed c

arbo

n (G

AC

) fi l

ters

at

Mar

oon

Dam

. •

The

clo

sure

of t

he c

ampi

ng g

roun

ds b

y Le

slie

Dam

res

ulte

d in

a lo

ss in

tra

de fo

r th

e pa

rk k

iosk

. •

Faci

litie

s at

Sol

omon

Dam

, Pal

m Is

land

, hav

e be

en u

pgra

ded

to in

clud

e an

aer

ator

and

the

opt

ion

of p

owde

red

activ

ated

car

bon

(PA

C) fi l

trat

ion.

•

Cos

t of

pos

sibl

e de

crea

se in

cus

tom

er b

ase

due

to s

witc

hing

to

priv

ate

supp

lies.

• C

ost

of in

crea

sed

mon

itori

ng v

igila

nce.

Prev

entiv

e M

easu

res

• PA

C fi

ltrat

ion/

dosi

ng o

r G

AC

fi ltr

atio

n (fo

r ta

ste

and

odou

r pr

oble

ms)

• A

erat

ion

(am

elio

rate

s de

oxyg

enat

ing

tend

ency

).

• Sw

itch

to a

ltern

ativ

e su

pply

(e.

g. g

roun

dwat

er, a

noth

er s

urfa

ce s

tora

ge)

• D

osin

g w

ith c

oppe

r su

lfate

doe

s no

t ap

pear

to

be a

pra

ctic

al o

ptio

n in

mos

t ca

ses.

4

Ref

eren

ces

Que

ensl

and

Wat

er Q

ualit

y Ta

sk F

orce

(O

ctob

er 1

992)

. R

epor

t on

Fre

shw

ater

Alg

al B

loom

s in

Que

ensl

and,

Vol

ume

I, M

ain

Rep

ort

[See

als

o Vo

lum

e II

]

R. R

esso

m e

t alia

(19

94).

Hea

lth E

ffect

s of

Tox

ic C

yano

bact

eria

(Bl

ue-G

reen

Alg

ae),

Cha

pter

5.

Loca

tion

and

Dat

eSo

uth

East

Que

ensl

and,

Aus

tral

ia. A

ugus

t 19

91 –

Sep

tem

ber

1992

. (M

aroo

n D

am, B

oona

h: A

pril

1992

– Ju

ne 1

992;

Les

lie D

am, W

arw

ick:

Mar

ch 1

992

– Ju

ly 1

992;

see

ref

eren

ces

for

othe

r st

orag

es).

1 T

his

is p

artic

ular

ly u

nusu

al a

s tr

opic

al c

ondi

tions

(e.

g w

ater

tem

pera

ture

s >

30

degr

ees

Cel

sius

) ge

nera

lly d

o no

t fa

vour

alg

al g

row

th.

2 Mar

oon

Dam

, Boo

nah

(wat

er c

arte

r in

); Lo

uden

Wie

r/C

onda

min

e R

iver

, Dal

by (

grou

ndw

ater

use

d); L

eslie

Dam

, War

wic

k (C

onno

lly D

am, g

roun

dwat

er);

Kilk

ivan

(ra

inw

ater

or

othe

r); G

oom

eri

(gro

undw

ater

): Le

slie

Har

riso

n D

am, R

edla

nds

Shir

e (u

sed

Stra

dbro

ke Is

land

sup

ply)

: Sta

nwel

l Pow

er S

tatio

n, Q

uarr

y C

reek

(bo

re w

ater

).3 T

his

is m

ore

likel

y if

the

stor

age

has

a hi

stor

y of

pro

blem

s w

ith a

lgae

.4 D

osin

g at

abo

ut 1

ppm

kill

s m

uch

(but

not

nec

essa

rily

all)

of t

he a

lgae

, but

the

cel

l lys

is in

volv

ed c

ause

s re

leas

e of

any

tox

ins

pres

ent.

The

cop

per

may

als

o le

ad t

o ac

ute

copp

er p

oiso

ning

if in

gest

ed.

Furt

herm

ore,

at

Lesl

ie H

arri

son

Dam

, “as

soo

n as

dos

ing

stop

ped

num

bers

[of

alg

ae]

incr

ease

d ag

ain.

”

Ref

er t

o th

e fo

llow

ing

Haz

ard

Fact

She

ets

(App

endi

x A

) fo

r de

tails

of r

elat

ed h

azar

ds:

10. A

lgal

Blo

oms

with

in R

eser

voir

s15

. WT

P D

esig

n C

apab

ility

- T

oxin

s


100


101

Appendix CSummary of Hazards

(Contaminants)


102

AP

PE

ND

IX C

– S

UM

MA

RY

OF

HA

ZA

RD

S (

CO

NT

AM

INA

NT

S)

Thi

s su

mm

ary

is p

rovi

ded

as a

qui

ck r

efer

ence

gui

de t

o th

e m

ost

com

mon

con

tam

inan

ts fo

und

in A

ustr

alia

.

For

mor

e de

taile

d in

form

atio

n, p

leas

e re

fer

to t

he A

ustr

alia

n D

rink

ing W

ater

Gui

delin

es c

onta

min

ant

fact

she

ets.

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Mic

ro-o

rgan

ism

s

Ba

cter

ia

Aer

omon

asC

omm

on in

fres

h w

ater

and

soi

lT

he a

bsen

ce o

f the

rmot

oler

ant

colif

orm

s (o

r al

tern

ativ

ely

E.co

li)

and

colif

orm

s d

oe

s n

ot

indi

cate

the

abs

ence

of A

erom

onas

.

A s

pecifi c

tes

t fo

r Aer

omon

as is

req

uire

d to

det

ect

this

or

gani

sm.

Dir

ect

caus

ativ

e lin

k be

twee

n A

erom

onas

and

hea

lth e

ffect

s is

no

t cl

ear,

how

ever

it h

as b

een

asso

ciat

ed w

ith g

astr

oent

eriti

s in

ch

ildre

n, d

iarr

hoea

, and

wou

nd in

fect

ions

.

Cam

pylo

bact

erH

as b

een

iden

tifi e

d in

som

e w

ater

su

pplie

s, bu

t th

ere

have

bee

n no

re

port

s of

infe

ctio

ns fr

om d

rink

ing

wat

er in

Aus

tral

ia.

The

rmot

oler

ant

colif

orm

s (o

r al

tern

ativ

ely

E.co

li) a

nd c

olifo

rms

can

be u

sed

to in

dica

te t

he p

ossi

ble

pres

ence

of p

atho

geni

c C

ampy

loba

cter

.

Acu

te g

astr

oent

eriti

s (c

ampy

loba

cter

iosi

s). S

peci

es s

uch

as C

ampy

loba

cter

jeju

ni is

res

pons

ible

for

mos

t ca

ses

of

cam

pylo

bact

erio

sis

at lo

w in

fect

ious

dos

e.

Col

iform

sVe

ry c

omm

on. U

sed

as a

n in

dica

tor

of d

isin

fect

ant

resi

dual

and

/or

the

clea

nlin

ess

of t

he w

ater

sup

ply.

Col

iform

s le

vels

sho

uld

be m

onito

red

freq

uent

ly t

o co

nsta

ntly

as

sess

the

cle

anlin

ess

of d

rink

ing

wat

er.

Use

d as

an

oper

atio

nal i

ndic

ator

of n

orm

al c

ondi

tions

(d

isin

fect

ant

resi

dual

s an

d/or

nut

rien

t le

vels

). C

olile

rt t

est

proc

edur

e no

w w

idel

y us

ed.

Not

a h

ealth

thr

eat

Sudd

en in

crea

ses

in c

olifo

rm le

vels

may

indi

cate

pro

blem

s w

ith

sour

ce w

ater

con

tam

inat

ion,

tre

atm

ent

failu

re o

r in

gres

s of

co

ntam

inat

ion

at t

anks

and

in d

istr

ibut

ion

syst

em, a

nd s

houl

d be

in

vest

igat

ed.

The

rmot

oler

ant

colif

orm

sM

ay b

e de

tect

ed a

t lo

w fr

eque

ncie

s in

dis

infe

cted

wat

er s

uppl

ies.

Use

d as

an

indi

cato

r of

the

pre

senc

e of

pa

thog

ens.

Use

d as

a s

urro

gate

for

E. c

oli

but

not

as s

pecifi c

an

indi

cato

r of

fa

ecal

pol

lutio

n. S

ome

ther

mot

oler

ant

colif

orm

s m

ay o

rigi

nate

fr

om n

on-fa

ecal

sou

rces

.

The

rmot

oler

ant

colif

orm

s sh

ould

not

be

dete

cted

in a

ny s

ampl

e of

dri

nkin

g w

ater

. Col

ilert

tes

t w

idel

y us

ed.

Not

a h

ealth

thr

eat

but

indi

cate

the

pos

sibl

e pr

esen

ce o

f pa

thog

ens.

Esch

eric

hia

coli

May

be

dete

cted

at

low

freq

uenc

ies

in d

isin

fect

ed w

ater

sup

plie

s. U

sed

as a

n in

dica

tor

of t

he p

rese

nce

of

path

ogen

s.

E.co

li is

rec

omm

ende

d as

the

mos

t sp

ecifi

c in

dica

tor

of fa

ecal

po

llutio

n in

dri

nkin

g w

ater

. Sho

uld

be m

onito

red

freq

uent

ly t

o as

sess

the

saf

ety

of t

he w

ater

sup

ply

E.co

li sh

ould

not

be

dete

cted

in a

ny s

ampl

e of

dri

nkin

g w

ater

.

The

maj

ority

of s

trai

ns a

re h

arm

less

but

indi

cate

the

pos

sibl

e pr

esen

ce o

f fae

cal p

atho

gens

. Som

e st

rain

s ar

e en

teri

c pa

thog

ens,

caus

ing

gast

roen

teri

tis, d

iarr

hoea

and

som

etim

es

deat

h.

Kle

bsie

llaH

as b

een

iden

tifi e

d in

som

e w

ater

su

pplie

s, bu

t th

ere

have

bee

n no

ev

iden

ce o

f inf

ectio

ns fr

om d

rink

ing

wat

er in

Aus

tral

ia.

Kle

bsie

lla fo

rm a

sig

nifi c

ant

prop

ortio

n of

the

rmot

oler

ant

colif

orm

s id

entifi

ed

in s

tand

ard

test

s, an

d ar

e th

us c

over

ed b

y th

e gu

idel

ine

for

ther

mot

oler

ant

colif

orm

s.

Som

e K

lebs

iella

are

of n

on-fa

ecal

ori

gin.

Col

onis

atio

n m

ay o

ccur

in p

eopl

e w

ith im

pair

ed im

mun

e sy

stem

s, fr

om w

hich

inva

sive

infe

ctio

ns m

ay o

ccur

cau

sing

de

stru

ctiv

e pn

eum

onia

.


103

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Legi

onel

laPr

obab

ly r

are

in d

rink

ing

wat

er, b

ut n

o re

port

s on

its

pres

ence

are

ava

ilabl

e.Sp

ecifi

c m

onito

ring

is u

sual

ly n

ot r

equi

red

for

Legi

onel

la

beca

use

spec

ies

of c

once

rn:

• oc

cur

very

rar

ely

in d

rink

ing

wat

er

• ar

e el

imin

ated

whe

n w

ater

is d

isin

fect

ed w

ith c

hlor

ine

or

chlo

ram

ines

.

Mon

itori

ng m

ay b

e re

quir

ed in

sta

gnan

t ar

eas

whe

re w

ater

te

mpe

ratu

re is

bet

wee

n 20

° an

d 60

°.

Legi

onel

la p

neum

ophi

la s

peci

es c

ause

s Le

gion

ello

sis

(a fo

rm o

f pn

eum

onia

), or

Pon

tiac

feve

r w

hich

has

sim

ilar

sym

ptom

s to

se

vere

infl u

enza

.

Infe

ctio

ns a

re a

ssoc

iate

d w

ith g

row

th o

f the

Leg

ione

lla

pneu

mop

hilia

bac

teri

a in

war

m w

ater

sys

tem

s an

d pr

oduc

tion

of

aero

sols

with

dro

plet

s sm

all e

noug

h to

be

deep

ly in

hale

d.

Myc

obac

teri

umG

ener

ally

com

mon

, but

pat

hoge

nic

spec

ies

are

infr

eque

nt.

Spec

ifi c

mon

itori

ng is

not

req

uire

d fo

r M

ycob

acte

rium

.T

here

is o

nly

circ

umst

antia

l evi

denc

e of

a r

elat

ions

hip

betw

een

Myc

obac

teri

um a

nd h

uman

dis

ease

. Suc

h ev

iden

ce h

as li

nked

M

ycob

acte

rium

with

infe

ctio

ns o

f the

lung

s, sk

elet

on, l

ymph

no

des,

skin

and

sof

t tis

sues

, and

gen

eral

ly o

nly

invo

lves

peo

ple

with

impa

ired

imm

une

syst

ems.

Pseu

dom

onas

aer

ugin

osa

Com

mon

ly fo

und

in s

oil,

wat

er, a

nd

sew

age.

Whi

lst

spec

ifi c

mon

itori

ng is

not

req

uire

d, it

can

be

used

to

asse

ss t

he g

ener

al c

lean

lines

s of

wat

er d

istr

ibut

ion

syst

ems.

Hig

h co

unts

of t

his

orga

nism

in s

pa a

nd s

wim

min

g po

ol w

ater

ha

ve b

een

linke

d w

ith r

ashe

s an

d ea

r in

fect

ions

. In

rare

cas

es, i

t ca

n in

fect

wou

nds

or p

eopl

e w

ith im

pair

ed im

mun

e sy

stem

s.

Salm

onel

laVe

ry c

omm

on in

env

iron

men

t, ca

n en

ter

wat

er s

yste

ms

thro

ugh

faec

al

cont

amin

atio

n fr

om li

vest

ock

or

hum

ans.

The

rmot

oler

ant

colif

orm

s (o

r al

tern

ativ

ely

E.co

li) c

an b

e us

ed

to in

dica

te t

he p

ossi

ble

pres

ence

of p

atho

geni

c Sa

lmon

ella

.Pa

thog

enic

str

ains

of S

alm

onel

la c

an c

ause

gas

troe

nter

itis

with

di

arrh

oea,

or e

nter

ic fe

ver.

Shig

ella

No

conc

lusi

ve e

vide

nce

has

been

re

port

ed fo

r th

e tr

ansm

issi

on o

f Sh

igel

losi

s th

roug

h w

ater

sup

ply

syst

ems

in A

ustr

alia

.

The

rmot

oler

ant

colif

orm

s (o

r al

tern

ativ

ely

E.co

li) c

an b

e us

ed

to in

dica

te t

he p

ossi

ble

pres

ence

of p

atho

geni

c Sh

igel

la.

Shig

ella

is v

irul

ent,

has

a lo

w in

fect

ive

dose

, and

cau

ses

dyse

nter

y.


104

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Vib

rio

Man

y Vib

rio

spec

ies

are

foun

d co

mm

only

in t

he e

nvir

onm

ent.

V.ch

oler

ae (

chol

era)

has

bee

n fo

und

in

sour

ce w

ater

s in

Que

ensl

and.

The

rmot

oler

ant

colif

orm

s (o

r al

tern

ativ

ely

E.co

li) c

an b

e us

ed

to in

dica

te t

he p

ossi

ble

pres

ence

of p

atho

geni

c Vib

rio.

The

V.c

hole

rae

spec

ies

caus

es c

hole

ra, w

hich

invo

lves

sev

ere

diar

rhoe

a an

d de

hydr

atio

n.

Yers

inia

The

pre

vale

nce

of Y

ersi

nia

infe

ctio

n va

ries

bet

wee

n A

ustr

alia

n st

ates

.T

herm

otol

eran

t co

lifor

ms

(or

alte

rnat

ivel

y E.

coli)

can

be

used

to

indi

cate

the

pos

sibl

e pr

esen

ce o

f pat

hoge

nic Y

ersi

nia.

Path

ogen

ic s

trai

ns o

f Y.e

nter

ocol

itica

cau

se a

cute

gas

troe

nter

itis.

Pro

tozo

a

Aca

ntha

moe

baC

omm

on in

sou

rce

wat

er, a

nd v

ery

com

mon

in s

oils

.

May

act

as

host

cel

ls fo

r Le

gion

ella

.

No

spec

ifi c

mon

itori

ng is

req

uire

d du

e to

unc

erta

inty

as

to t

he

role

of w

ater

as

a so

urce

of i

nfec

tion.

Vir

ulen

t sp

ecie

s of

Aca

ntha

moe

ba c

an c

ause

the

cer

ebra

l in

fect

ion

GA

E in

peo

ple

with

com

prom

ised

imm

une

syst

ems.

The

ser

ious

eye

infe

ctio

n am

oebi

c ke

ratit

is h

as b

een

asso

ciat

ed

with

was

hing

con

tact

lens

es in

tap

wat

er.

Cry

ptos

pori

dium

Sp

ecie

sC

omm

on in

cat

tle, s

heep

, and

hum

an

faec

es.

Cry

pto.

num

bers

may

incr

ease

dur

ing

peri

ods

of h

igh

turb

idity

ass

ocia

ted

with

rai

nfal

l eve

nts.

No

spec

ifi c

mon

itori

ng is

pos

sibl

e du

e to

lack

of r

elia

ble

test

ing

proc

edur

es.

Inve

stig

ativ

e an

d sp

ecifi

c ev

ent

base

d te

stin

g is

rec

omm

ende

d.

Cry

ptos

pori

dium

affe

cts

norm

ally

hea

lthy

peop

le, c

ausi

ng

diar

rhoe

a fo

r pe

riod

s of

one

wee

k to

one

mon

th o

r m

ore.

Gia

rdia

Com

mon

in t

he e

nvir

onm

ent,

and

can

surv

ive

wel

l in

fres

h w

ater

.N

o sp

ecifi

c m

onito

ring

is p

ossi

ble

due

to la

ck o

f rel

iabl

e te

stin

g pr

oced

ures

.

Inve

stig

ativ

e an

d sp

ecifi

c ev

ent

base

d te

stin

g is

rec

omm

ende

d.

Cau

ses

diar

rhoe

a an

d re

duce

d ab

sorp

tion

of n

utri

ents

. Inf

ectio

n is

usu

ally

for

a sh

ort

peri

od, b

ut in

som

e ca

ses

can

beco

me

chro

nic

with

inte

rmitt

ent

diar

rhoe

a.

Nae

gler

ia fo

wle

riH

as b

een

dete

cted

in m

ost A

ustr

alia

n st

ates

.

Occ

urs

natu

rally

whe

re w

ater

te

mpe

ratu

re is

sea

sona

lly a

bove

30°

or

per

man

ently

abo

ve 2

5°.

Reg

ular

mon

itori

ng is

onl

y re

com

men

ded

for

wat

er s

yste

ms

susc

eptib

le t

o co

loni

satio

n.T

his

orga

nism

, inf

ectin

g pe

ople

thr

ough

the

nos

e w

hile

th

ey a

re b

athi

ng, c

ause

s th

e fa

tal d

isea

se P

rim

ary

Am

oebi

c M

enin

goen

ceph

aliti

s. M

ost

infe

ctio

ns a

re a

ssoc

iate

d w

ith ju

mpi

ng

into

riv

ers

or d

ams

or s

quir

ting

wat

er in

to t

he n

ose,

forc

ing

wat

er i

nto

the

nasa

l sin

us c

aviti

es.

To

xic

Alg

ae

Cya

noba

cter

iaC

omm

on in

ope

n w

ater

whe

n w

arm

te

mpe

ratu

res,

sunl

ight

, nut

rien

ts, a

nd

calm

wat

er a

re a

vaila

ble.

Susc

eptib

le w

ater

sou

rces

sho

uld

be m

onito

red

wee

kly

for

cyan

obac

teri

a, an

d if

leve

ls a

re h

igh,

tox

icity

sho

uld

be t

este

d.Pa

thog

enic

spe

cies

of c

yano

bact

eria

rel

ease

tox

ins

whi

ch c

an

dam

age

eith

er li

ver

cells

or

nerv

e ce

lls. C

onta

ct w

ith w

ater

su

ppor

ting

a bl

oom

may

cau

se a

n itc

hy d

erm

atiti

s.

Vir

use

s

Ade

novi

ruse

sA

deno

viru

ses

have

not

bee

n de

tect

ed

in d

rink

ing

wat

er in

Aus

tral

ia, p

roba

bly

due

to p

ract

ical

diffi

cul

ties

with

de

tect

ion.

Tran

smis

sion

thr

ough

dri

nkin

g w

ater

is p

rim

arily

thr

ough

co

ntam

inat

ion

with

faec

es. T

hus,

ther

mot

oler

ant

colif

orm

s (o

r al

tern

ativ

ely

E.co

li) c

an b

e us

ed t

o in

dica

te t

he p

ossi

ble

pres

ence

of p

atho

geni

c A

deno

viru

ses.

Som

e sp

ecie

s of

ade

novi

rus

can

caus

e ph

aryn

gitis

, con

junc

tiviti

s, an

d ga

stro

ente

ritis

.


105

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Ente

rovi

ruse

sEn

tero

viru

ses

have

not

bee

n de

tect

ed

in d

rink

ing

wat

er in

Aus

tral

ia, p

roba

bly

due

to p

ract

ical

diffi

cul

ties

with

de

tect

ion.

The

y ar

e ve

ry c

omm

on in

al

l oth

er p

arts

of t

he w

orld

.

Tran

smis

sion

thr

ough

dri

nkin

g w

ater

is p

rim

arily

thr

ough

co

ntam

inat

ion

with

faec

es. T

hus,

ther

mot

oler

ant

colif

orm

s (o

r al

tern

ativ

ely

E.co

li) c

an b

e us

ed t

o in

dica

te t

he p

ossi

ble

pres

ence

of p

atho

geni

c En

tero

viru

ses.

Ente

rovi

rus

infe

ctio

ns c

an b

e sy

mpt

omle

ss, b

ut in

0.1

% t

o 1%

of c

ases

can

cau

se s

ore

thro

ats,

rash

es, a

sept

ic m

enin

gitis

, ga

stro

ente

ritis

, car

diac

sym

ptom

s, an

d co

njun

ctiv

itis.

Hep

atiti

s Vir

uses

Hep

atiti

s vi

ruse

s ha

ve n

ot b

een

dete

cted

in d

rink

ing

wat

er in

Aus

tral

ia,

prob

ably

due

to

prac

tical

diffi

cul

ties

with

det

ectio

n.

Hep

atiti

s A is

rea

sona

bly

com

mon

in

the

Aus

tral

ian

com

mun

ity, b

ut

Hep

atiti

s E

is r

are

and

occu

rs m

ainl

y in

ret

urni

ng t

rave

llers

from

Asi

a.

Tran

smis

sion

of H

epat

itis A

and

E t

hrou

gh d

rink

ing

wat

er is

th

roug

h co

ntam

inat

ion

with

hum

an fa

eces

. Thu

s, th

erm

otol

eran

t co

lifor

ms

(or

alte

rnat

ivel

y E.

coli)

can

be

used

to

indi

cate

the

po

ssib

le p

rese

nce

of H

epat

itis.

Hep

atiti

s A in

fect

ions

hav

e be

en r

elat

ed t

o fa

ecal

con

tam

inat

ion

of w

ater

use

d fo

r gr

owin

g sh

ellfi

sh a

s th

e vi

rus

is c

once

ntra

ted

by t

hese

fi lte

r-fe

edin

g an

imal

s.

Hep

atiti

s B,

C, a

nd D

are

not

spr

ead

thro

ugh

drin

king

wat

er.

Hep

atiti

s A m

ay c

ause

mild

sym

ptom

s (w

hich

can

be

mis

take

n fo

r ga

stro

ente

ritis

) or

mor

e se

vere

illn

ess

(jaun

dice

) an

d ra

rely

de

ath.

Hep

atiti

s E

sym

ptom

s ar

e ge

nera

lly m

ild e

xcep

t in

wom

en in

th

e la

te s

tage

s of

pre

gnan

cy, w

here

the

ris

k of

dea

th is

as

high

as

20%

Nor

wal

k V

irus

Nor

wal

k vi

rus

has

not

been

det

ecte

d in

dri

nkin

g w

ater

in A

ustr

alia

, pro

babl

y du

e to

pra

ctic

al d

iffi c

ultie

s w

ith

dete

ctio

n. O

ther

sim

ilar

viru

ses

may

be

pres

ent,

but

have

not

bee

n defi n

itive

ly c

lass

ifi ed

.

Tran

smis

sion

thr

ough

dri

nkin

g w

ater

is t

hrou

gh c

onta

min

atio

n w

ith h

uman

faec

es. O

ther

infe

ctio

ns h

ave

been

rel

ated

to

faec

al c

onta

min

atio

n of

wat

er u

sed

for

grow

ing

shel

lfi sh

. Thu

s, th

erm

otol

eran

t co

lifor

ms

(or

alte

rnat

ivel

y E.

coli)

can

be

used

to

indi

cate

the

pos

sibl

e pr

esen

ce o

f Nor

wal

k vi

rus.

Nor

wal

k vi

rus

infe

ctio

ns u

sual

ly c

ause

rap

id e

pide

mic

s of

ga

stro

ente

ritis

, and

som

etim

es a

lso

caus

e vo

miti

ng, f

ever

, and

ch

ills.

Sym

ptom

s m

ay b

e in

tens

e bu

t ar

e ty

pica

lly o

f sho

rt

dura

tion

(48

hour

s or

less

).

Rot

avir

uses

Para

-rot

avir

uses

Reo

viru

s (R

eovi

rida

e)

Extr

emel

y w

ides

prea

d. R

eovi

rida

e ha

ve n

ot b

een

dete

cted

in d

rink

ing

wat

er in

Aus

tral

ia, p

roba

bly

due

to

prac

tical

diffi

cul

ties

with

det

ectio

n.

Tran

smis

sion

thr

ough

dri

nkin

g w

ater

is t

hrou

gh c

onta

min

atio

n w

ith h

uman

faec

es. T

hus,

ther

mot

oler

ant

colif

orm

s (o

r al

tern

ativ

ely

E.co

li) c

an b

e us

ed t

o in

dica

te t

he p

ossi

ble

pres

ence

of R

eovi

rida

e.

Reo

viru

ses

have

not

bee

n pr

oved

to

caus

e di

seas

e in

hum

ans,

but

have

bee

n as

soci

ated

with

res

pira

tory

infe

ctio

ns a

nd

gast

roen

teri

tis.

Rot

avir

uses

are

res

pons

ible

for

a la

rge

prop

ortio

n of

cas

es o

f se

vere

gas

troe

nter

itis

in c

hild

ren

and

the

elde

rly.

Feve

r an

d vo

miti

ng a

re o

ther

sym

ptom

s. O

ccas

iona

lly fa

tal.

Para

-rot

avir

uses

hav

e be

en r

espo

nsib

le fo

r m

ajor

gas

troe

nter

itis

outb

reak

s in

adu

lts in

Chi

na.


106

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Ph

ysic

al

Ch

arac

teri

stic

s

Dis

solv

ed O

xyge

nLo

w le

vels

may

occ

ur if

:

• w

ater

is d

raw

n fr

om d

eep

stor

ages

in

sum

mer

;

• th

ere

is c

onsi

dera

ble

mic

ro-

orga

nism

gro

wth

in p

ipel

ines

;

• w

ater

is s

ubje

ct t

o pr

olon

ged

high

te

mpe

ratu

re a

nd d

elay

tim

e in

pi

pelin

es.

The

re is

no

need

to

mon

itor

diss

olve

d ox

ygen

(D

O)

leve

ls

dire

ctly.

How

ever

, low

DO

leve

ls m

ay c

ause

gro

wth

of a

naer

obic

m

icro

-org

anis

ms

whi

ch r

esul

t in

red

uced

pH

. Bot

h m

icro

-or

gani

sm le

vels

and

pH

sho

uld

be m

onito

red.

Low

oxy

gen

leve

ls m

ay c

ause

gro

wth

of a

naer

obic

mic

ro-

orga

nism

s. T

his

can

caus

e lo

calis

ed p

H c

hang

es le

adin

g to

co

rros

ion

and

odou

r. So

me

anae

robi

c m

icro

-org

anis

ms

coul

d po

tent

ially

be

path

ogen

ic.

Har

dnes

sH

ardn

ess

of s

ourc

e w

ater

s va

ries

co

nsid

erab

ly, b

ut is

eas

ily t

reat

ed.

Trea

tmen

t is

exp

ensi

ve h

owev

er a

nd

requ

ires

sed

imen

tatio

n an

d fi l

trat

ion.

Har

dnes

s sh

ould

be

dire

ctly

mon

itore

d in

dri

nkin

g w

ater

. If

wat

er is

bei

ng t

reat

ed t

o re

duce

har

dnes

s, pH

and

alk

alin

ity

shou

ld b

e ca

refu

lly m

onito

red

also

.

Soft

wat

er m

ay le

ad t

o ex

cess

ive

corr

osio

n.

Har

d w

ater

may

lead

to

exce

ssiv

e sc

alin

g of

pip

es a

nd fi

ttin

gs.

Har

d w

ater

may

hav

e so

me

posi

tive

heal

th e

ffect

s, bu

t no

defi n

ite r

elat

ions

hip

has

been

est

ablis

hed.

Mor

e so

ap is

req

uire

d to

mak

e a

lath

er w

hen

usin

g ha

rd w

ater

.

pHpH

can

var

y co

nsid

erab

ly in

sou

rce

wat

er, a

nd c

an b

e ch

ange

d du

ring

tr

eatm

ent

proc

esse

s (e

g al

um

coag

ulat

ion)

.

pH s

houl

d be

con

tinuo

usly

mon

itore

d in

sou

rce

wat

er, a

fter

tr

eatm

ent,

and

afte

r di

sinf

ectio

n.Ty

pica

lly, p

H o

f 6.5

or

low

er w

ill r

esul

t in

exc

essi

ve c

oppe

r, ir

on

and

cem

ent

linin

g co

rros

ion,

and

pH

of 8

.5 o

r hi

gher

will

res

ult

in e

xces

sive

sca

ling.

pH le

vels

affe

ct d

isin

fect

ion

effi c

ienc

y, de

pend

ing

on t

he

disi

nfec

tant

use

d.

Tast

e an

d O

dour

Tast

e an

d od

our

vari

es c

onsi

dera

bly

as a

res

ult

of d

iffer

ent

sour

ce w

ater

s, tr

eatm

ent

proc

esse

s, co

ntam

inat

ion,

an

d di

stri

butio

n sy

stem

s. Se

nsiti

vity

al

so v

arie

s de

pend

ing

on t

he in

divi

dual

co

nsum

er.

Tast

e an

d od

our

cann

ot b

e m

onito

red

cont

inuo

usly.

Usu

ally

wat

er a

utho

ritie

s m

onito

r an

d re

cord

com

plai

nts

of

tast

e an

d od

our.

Free

res

idua

l chl

orin

e le

vels

in e

xces

s of

0.6

m

g/L

can

resu

lt in

chl

orin

e ta

ste/

odou

r co

mpl

aint

s.

Sudd

en c

hang

es in

tas

te a

nd o

dour

will

res

ult

in c

usto

mer

co

mpl

aint

s. T

hey

may

als

o in

dica

te a

pro

blem

with

the

sys

tem

su

ch a

s m

alfu

nctio

ning

dis

infe

ctio

n or

tre

atm

ent

proc

esse

s, in

crea

sed

mic

robi

olog

ical

act

ivity

, or

cont

amin

atio

n of

the

so

urce

wat

er.

Tem

pera

ture

Vari

es d

epen

ding

on

the

seas

on,

sour

ce w

ater

and

dis

trib

utio

n sy

stem

(a

bove

gro

und

pipe

s of

ten

incr

ease

w

ater

tem

pera

ture

). In

Aus

tral

ia,

drin

king

wat

er is

usu

ally

bet

wee

n 10

° an

d 30

°.

Shou

ld b

e m

onito

red

inte

rmitt

ently

at

trea

tmen

t an

d di

sinf

ectio

n pl

ants

as

tem

pera

ture

can

affe

ct t

he p

erfo

rman

ce o

f th

ese

proc

esse

s.

Low

tem

pera

ture

s re

duce

the

effe

ctiv

enes

s of

fl oc

cula

tion

and

sedi

men

tatio

n. R

ates

are

slo

wer

in c

old

wat

er a

nd p

erfo

rman

ce

can

dete

rior

ate

dram

atic

ally

if r

apid

cha

nge

in w

ater

te

mpe

ratu

re o

ccur

s

Hig

h te

mpe

ratu

res

incr

ease

the

effe

ctiv

enes

s of

chl

orin

e do

sing

, bu

t in

crea

ses

the

rate

of c

hlor

ine

lost

to

the

atm

osph

ere.

Hig

h te

mpe

ratu

res

incr

ease

the

rat

e of

cor

rosi

on a

nd s

calin

g in

pi

pes.

Tota

l Dis

solv

ed S

olid

s (T

DS)

Vari

es d

epen

ding

on

sour

ce w

ater

.El

ectr

ical

con

duct

ivity

sho

uld

be m

easu

red

regu

larl

y as

an

indi

cato

r of

tot

al d

isso

lved

sol

ids,

part

icul

arly

if it

is a

sig

nifi c

ant

fact

or fo

r a

trea

tmen

t pr

oces

s (e

g re

vers

e os

mos

is).

Wat

er w

ith lo

w T

DS

may

tas

te fl

at.

Wat

er w

ith h

igh

TD

S m

ay b

e as

soci

ated

with

exc

essi

ve

corr

osio

n or

sca

ling

in p

ipes

and

fi tt

ings

.

Hig

h T

DS

may

red

uce

pala

tabi

lity

of w

ater

.


107

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

True

Col

our

Vari

es d

epen

ding

on

sour

ce w

ater

, and

co

nditi

on o

f dis

trib

utio

n sy

stem

and

ho

useh

old

pipe

s.

Col

our

shou

ld b

e m

onito

red

freq

uent

ly o

r co

ntin

uous

ly fo

r ra

w

and

trea

ted

wat

er t

o as

sess

per

form

ance

.C

olou

r is

gen

eral

ly r

elat

ed t

o or

gani

c co

nten

t, th

eref

ore

sudd

en in

crea

ses

in c

olou

r m

ay b

e as

soci

ated

with

incr

ease

s in

m

icro

biol

ogic

al a

ctiv

ity.

Col

our

itsel

f is

not

a he

alth

issu

e, a

lthou

gh it

can

red

uce

the

effi c

ienc

y of

dis

infe

ctio

n.

Turb

idity

Vari

es w

idel

y de

pend

ing

on

sour

ce w

ater

and

rai

nfal

l eve

nts

in

catc

hmen

ts.

Turb

idity

sho

uld

be c

ontin

uous

ly m

onito

red,

in p

artic

ular

so

that

any

‘‘sp

ikes

” in

tur

bidi

ty le

vels

can

be

imm

edia

tely

iden

tifi e

d.

Turb

idity

spi

kes

in u

ntre

ated

wat

er a

re o

ften

cau

sed

by

stor

m e

vent

s su

ch a

s he

avy

rain

fall,

and

is o

ften

ass

ocia

ted

with

incr

ease

d m

icro

biol

ogic

al a

ctiv

ity a

nd t

oxic

com

poun

d co

ntam

inat

ion

(eg.

herb

icid

e w

asho

ff). I

t is

als

o a

key

perf

orm

ance

indi

cato

r fo

r fi l

trat

ion

plan

ts.

Turb

idity

itse

lf is

not

a h

ealth

ris

k.

The

sus

pend

ed p

artic

les

whi

ch c

ause

tur

bidi

ty c

an c

arry

mic

ro-

orga

nism

s, w

hich

are

pot

entia

lly p

atho

geni

c. A

lso,

par

ticle

s ca

n ab

sorb

var

ious

tox

ic c

ompo

unds

.

Tu

rbid

ity

can

sh

ield

mic

ro-o

rgan

ism

s fr

om

d

isin

fect

ion

.


108

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Ino

rgan

ic C

he

mic

als

Alu

min

ium

Com

mon

in s

ourc

e w

ater

s du

e to

na

tura

l lea

chin

g fr

om s

oil a

nd r

ock.

May

als

o be

pre

sent

due

to

use

of

alum

as

a co

agul

ant.

Reg

ular

mon

itori

ng is

rec

omm

ende

d du

ring

tre

atm

ent

with

al

umin

ium

bas

ed c

oagu

lant

s. In

crea

sing

alu

min

ium

leve

ls in

tr

eate

d w

ater

sug

gest

s in

adeq

uate

tre

atm

ent

perf

orm

ance

and

co

uld

resu

lt in

inad

equa

te p

atho

gen

redu

ctio

n.

If so

lubl

e al

umin

ium

is m

ore

than

0.2

mg/

L af

ter

trea

tmen

t ch

ain,

al

umin

ium

hyd

roxi

de m

ay p

reci

pita

te in

the

dis

trib

utio

n sy

stem

.

Alu

min

ium

has

bee

n as

soci

ated

with

tw

o se

vere

bra

in d

isea

ses,

Park

inso

n’s

dise

ase

and

Am

ytro

phic

Lat

eral

Scl

eros

is.

To d

ate,

the

re is

no

clea

r lin

k be

twee

n al

umin

ium

and

A

lzhe

imer

’s di

seas

e.

Am

mon

iaH

igh

amm

onia

leve

ls a

re

usua

lly c

ause

d by

sou

rce

wat

er

cont

amin

atio

n, o

r by

a m

alfu

nctio

n of

ch

lora

min

e di

sinf

ectio

n eq

uipm

ent.

Reg

ular

mon

itori

ng o

f am

mon

ia le

vels

is w

arra

nted

, as

it is

fo

rmed

dur

ing

the

brea

kdow

n of

org

anic

pol

lutio

n.

Reg

ular

mon

itori

ng o

f am

mon

ia le

vels

in t

he d

istr

ibut

ion

syst

em

shou

ld o

ccur

aft

er c

hlor

amin

e di

sinf

ectio

n to

ens

ure

the

corr

ect

oper

atio

n of

am

mon

ia d

osin

g.

Am

mon

ia in

wat

er c

an c

ause

the

cor

rosi

on o

f cop

per

pipe

s an

d fi t

tings

, res

ultin

g in

blu

e st

aini

ng.

Onl

y a

heal

th is

sue

if pr

esen

t in

ext

rem

ely

high

con

cent

ratio

ns.

Ant

imon

yU

ncom

mon

in s

ourc

e w

ater

s, hi

gh

leve

ls w

ould

like

ly b

e th

e re

sult

of c

onta

min

atio

n w

ith in

dust

rial

ch

emic

als

/ pro

duct

s / m

inin

g.

Reg

ular

mon

itori

ng n

ot r

equi

red.

Spec

ifi c

even

t ba

sed

test

ing

is w

arra

nted

if p

rese

nce

is

susp

ecte

d.

Onl

y a

heal

th t

hrea

t if

dose

s ar

e pe

rsis

tent

and

long

ter

m.

Ars

enic

Hig

h co

ncen

trat

ions

of a

rsen

ic

com

poun

ds a

re r

are.

May

res

ult

from

nat

ural

leac

hing

fr

om r

ock

in a

gro

undw

ater

aqu

ifer,

indu

stri

al c

onta

min

atio

n, d

rain

age

from

old

gol

d m

ines

, or

cont

amin

atio

n w

ith s

ome

type

s of

she

ep d

ip.

Reg

ular

mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

su

spec

ted.

Bore

wat

ers

can

cont

ain

sign

ifi ca

nt c

once

ntra

tions

of a

rsen

ic

and

wat

er s

houl

d be

tes

ted

at e

xist

ing

bore

s w

hen

drill

ing

test

bo

res

for

new

sup

plie

s.

Long

ter

m e

xpos

ure

to r

elat

ivel

y m

oder

ate

arse

nic

leve

ls c

an

have

a r

ange

of s

ever

e he

alth

effe

cts.

Ars

enic

is h

ighl

y to

xic

at v

ery

high

dos

es.

Asb

esto

sC

once

ntra

tions

of a

sbes

tos

in w

ater

ar

e us

ually

ass

ocia

ted

with

asb

esto

s ce

men

t pi

pes

dete

rior

atin

g.

Reg

ular

mon

itori

ng is

not

req

uire

d.

Inha

led

asbe

stos

can

be

high

ly c

arci

noge

nic.

The

re is

som

e ev

iden

ce t

hat

inge

stin

g as

best

os in

wat

er is

not

ha

rmfu

l.

Cad

miu

mH

igh

conc

entr

atio

ns o

f cad

miu

m

com

poun

ds a

re r

are.

May

res

ult

from

impu

ritie

s in

the

zin

c of

gal

vani

sed

pipe

s so

lder

ed fi

ttin

gs, o

r in

dust

rial

con

tam

inat

ion.

Reg

ular

mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

su

spec

ted.

Long

ter

m e

xpos

ure

to c

adm

ium

can

cau

se k

idne

y fa

ilure

. Als

o,

it is

pro

babl

y ca

rcin

ogen

ic.

Chl

orin

eW

ill b

e pr

esen

t in

dri

nkin

g w

ater

w

hen

chlo

rine

or

chlo

ram

ine

disi

nfec

tion

is u

sed.

Con

tinuo

us m

onito

ring

is n

eces

sary

dow

nstr

eam

of t

he

disi

nfec

tion

poin

t to

det

erm

ine

the

resi

dual

chl

orin

e co

ncen

trat

ion

at d

iffer

ent

poin

ts in

the

dis

trib

utio

n sy

stem

.

Not

ver

y to

xic

to h

uman

s un

less

pre

sent

in v

ery

high

co

ncen

trat

ions

. How

ever

, mos

t pe

ople

will

fi nd

wat

er

obje

ctio

nabl

e at

muc

h lo

wer

leve

ls d

ue t

o th

e ch

lori

ne o

dour

.

Chl

orin

e D

ioxi

deC

hlor

iteC

hlor

ate

Will

be

pres

ent

in d

rink

ing

wat

er

whe

n ch

lori

ne d

ioxi

de d

isin

fect

ion

is

used

. It

form

s ch

lori

te a

nd c

hlor

ate

whe

n ad

ded

to w

ater

.

Con

tinuo

us m

onito

ring

of c

hlor

ite c

once

ntra

tion

is n

eces

sary

do

wns

trea

m o

f the

dis

infe

ctio

n po

int.

Long

ter

m e

xpos

ure

to h

igh

chlo

rine

dio

xide

/ ch

lori

te

conc

entr

atio

ns c

an a

ffect

hea

lth. H

owev

er, m

ost

peop

le w

ill

refu

se t

o dr

ink

the

wat

er a

t m

uch

low

er d

oses

tha

n th

ose

repr

esen

ting

a he

alth

ris

k du

e to

the

chl

orin

e od

our.


109

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Chr

omiu

mC

hrom

ium

in it

s tr

ival

ent

stat

e is

pr

esen

t in

sm

all a

mou

nts

in m

ost

soils

an

d ro

cks.

Hex

aval

ent

chro

miu

m is

rar

e,

its p

rese

nce

wou

ld b

e du

e to

co

ntam

inat

ion

with

indu

stri

al

chem

ical

s.

Reg

ular

mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

su

spec

ted.

Whe

n in

hale

d, h

exav

alen

t ch

rom

ium

com

poun

ds c

an b

e ca

rcin

ogen

ic.

The

re is

no

evid

ence

tha

t in

gest

ed h

exav

alen

t ch

rom

ium

co

mpo

unds

cau

se c

ance

r.

Cop

per

Pres

ent

in s

ourc

e w

ater

in lo

w

conc

entr

atio

ns. H

igh

conc

entr

atio

ns

can

easi

ly o

ccur

whe

n w

ater

of l

ow

pH a

nd h

ardn

ess

are

in s

tagn

ant

cont

act

with

cop

per

pipe

s an

d fi t

tings

.

Mon

itori

ng c

oppe

r co

ncen

trat

ions

is im

prac

tical

, sin

ce m

ost

copp

er e

nter

s th

e w

ater

in d

omes

tic p

ipew

ork.

Mai

ntai

ning

pH

and

alk

alin

ity le

vels

at

appr

opri

ate

leve

ls w

ill

redu

ce c

oppe

r co

ncen

trat

ions

at

the

tap.

Extr

emel

y hi

gh d

oses

of c

oppe

r (5

0mg/

L) c

an b

e le

thal

.

Con

cent

ratio

ns a

bove

2m

g/L

may

res

ult

in h

ealth

effe

cts

in

sens

itive

indi

vidu

als.

Con

cent

ratio

ns a

bove

1m

g/L

will

cau

se b

lue

disc

olou

ratio

n,

stai

ning

of s

anita

ry w

are

and

poor

tas

te.

Cya

nide

Cya

nide

in d

rink

ing

wat

er c

an r

esul

t fr

om in

dust

rial

con

tam

inat

ion

or

deco

mpo

sitio

n of

som

e ki

nds

of

plan

ts.

Reg

ular

mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

su

spec

ted.

Som

e fo

rms

of c

yani

de a

re h

ighl

y to

xic.

Long

ter

m lo

w le

vel d

oses

may

cau

se v

itam

in B

12 d

efi c

ienc

y, ca

usin

g go

itre

and

cret

inis

m.

Fluo

ride

Con

cent

ratio

ns in

sur

face

wat

er a

re

gene

rally

ver

y lo

w, b

ut s

ome

grou

nd

wat

ers

can

have

hig

h co

ncen

trat

ions

de

pend

ing

on t

he c

ompo

sitio

n of

the

aq

uife

rs.

Fluo

ride

leve

ls s

houl

d be

con

tinuo

usly

mon

itore

d if

the

supp

ly is

ar

tifi c

ially

fl uo

rida

ted.

Fluo

ride

hel

ps p

reve

nt d

enta

l car

ies.

Hig

h co

ncen

trat

ions

may

dis

turb

too

th m

iner

alis

atio

n in

ch

ildre

n. L

ong

term

exp

osur

e to

ver

y hi

gh c

once

ntra

tions

may

ca

use

skel

etal

fl uo

rosi

s.

Hyd

roge

n Su

lfi de

Gen

eral

ly r

are,

but

can

occ

ur w

here

th

e so

urce

wat

er h

as lo

w d

isso

lved

ox

ygen

leve

ls s

uch

as in

the

bot

tom

of

dee

p re

serv

oirs

whe

re w

ater

has

be

com

e an

aero

bic.

Mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

sus

pect

ed.

Hig

h co

ncen

trat

ions

of h

ydro

gen

sulp

hide

in a

ir a

re le

thal

. The

ro

tten

egg

odo

ur b

ecom

es h

ighl

y ob

ject

iona

ble

at m

uch

low

er

conc

entr

atio

ns.

The

mai

n ri

sk is

hyd

roge

n su

lfi de

dis

solv

ed g

as r

elea

se fr

om

solu

tions

whe

n pr

essu

re is

sud

denl

y re

duce

d at

leak

s or

use

po

int.

Iron

Low

con

cent

ratio

ns a

re c

omm

on

in s

ourc

e w

ater

s, bu

t hi

gh

conc

entr

atio

ns c

an o

ccur

at

the

tap

if un

lined

ste

el d

eliv

ery

pipe

s ar

e co

rrod

ed.

Rou

tine

mon

itori

ng is

nor

mal

as

it is

a g

ood

indi

cato

r of

‘d

irty

wat

er’ a

nd c

orro

sion

in p

ipe

netw

orks

. Als

o ro

utin

ely

mon

itore

d at

fi ltr

atio

n pl

ants

whe

re fe

rric

sal

ts a

re u

sed

as t

he

coag

ulan

t.

Hig

h co

ncen

trat

ions

of i

ron

may

cau

se h

ealth

pro

blem

s, bu

t th

e ta

ste

and

appe

aran

ce (

red

wat

er)

beco

me

high

ly o

bjec

tiona

ble

at m

uch

low

er c

once

ntra

tions

.

Lead

Can

res

ult

from

leac

hing

of s

oil a

nd

rock

, but

hig

h co

ncen

trat

ions

are

m

ore

com

mon

ly c

ause

d by

leac

hing

fr

om d

omes

tic le

ad p

ipew

ork

and

old

lead

-join

ted

wat

er m

ains

.

Rou

tine

mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

su

spec

ted,

sin

ce m

ost

lead

ent

ers

the

wat

er in

dom

estic

pi

pew

ork.

Lead

is a

cum

ulat

ive

pois

on, w

hich

affe

cts

the

nerv

ous

syst

em

and

redu

ces

inte

llige

nce.

Chi

ldre

n ab

sorb

4 t

o 5

times

mor

e le

ad t

han

adul

ts, a

nd t

hus

are

mor

e at

ris

k.


110

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Man

gane

seC

once

ntra

tions

var

y de

pend

ing

on

the

sour

ce w

ater

env

iron

men

t, bu

t ar

e us

ually

low

. Hig

h m

anga

nese

leve

ls

occu

r in

dee

p st

ratifi

ed

rese

rvoi

rs

over

sum

mer

/aut

umn.

Mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

sus

pect

ed.

Gen

eral

ly w

here

sup

ply

is d

raw

n fr

om d

eep

rese

rvoi

rs,

mon

itori

ng o

f profi l

es is

rec

omm

ende

d in

sum

mer

/aut

umn

to a

llow

sel

ectiv

e w

ithdr

awal

to

avoi

d m

anga

nese

ric

h de

eper

w

ater

laye

rs.

Man

gane

se w

ill c

ause

bla

ck s

limes

on

pipe

s an

d on

plu

mbi

ng

fi xtu

res

and

laun

dry

at lo

w c

once

ntra

tions

.

Slig

htly

hig

her

conc

entr

atio

ns w

ill c

ause

an

unpl

easa

nt t

aste

.

Inha

latio

n of

man

gane

se d

ust

is k

now

n to

cau

se h

ealth

effe

cts,

but

inge

sted

man

gane

se h

as v

ery

low

tox

icity

.

Mer

cury

Gen

eral

ly r

are.

Hig

h co

ncen

trat

ions

ar

e us

ually

cau

sed

by in

dust

rial

re

leas

es o

r sp

ills.

Old

gol

d m

ine

taili

ngs

can

leac

h m

ercu

ry.

Mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

sus

pect

ed.

Long

ter

m e

xpos

ure

to in

orga

nic

mer

cury

may

cau

se m

enta

l di

stur

banc

es, g

ingi

vitis

, and

kid

ney

failu

re.

Expo

sure

to

orga

nic

met

hyl m

ercu

ry c

ause

s se

vere

irre

vers

ible

ne

urol

ogic

al d

isor

der

and

men

tal d

isab

ility

.

Mol

ybde

num

Gen

eral

ly p

rese

nt in

sou

rce

wat

ers

in

very

low

con

cent

ratio

ns. A

lso

pres

ent

in fe

rtili

zer.

Mon

itori

ng n

ot r

equi

red

unle

ss it

s pr

esen

ce is

sus

pect

ed.

The

re is

lim

ited

evid

ence

tha

t ex

trem

ely

high

dos

es o

f M

olyb

denu

m m

ay c

ause

gou

t-lik

e sy

mpt

oms,

join

t pa

ins,

and

liver

enl

arge

men

t.

Mon

ochl

oram

ine

Oft

en u

sed

as a

n al

tern

ativ

e di

sinf

ecta

nt t

o ch

lori

ne.

If m

onoc

hlor

amin

e is

bei

ng u

sed

as a

dis

infe

ctan

t, its

res

idua

l co

ncen

trat

ions

sho

uld

be c

ontin

uous

ly m

onito

red

thro

ugho

ut

the

dist

ribu

tion

syst

em.

pH s

houl

d al

so b

e co

ntin

uous

ly m

onito

red

afte

r do

sing

, as

this

ca

n af

fect

the

con

cent

ratio

ns o

f mon

ochl

oram

ine

bypr

oduc

ts

whi

ch h

ave

low

er t

aste

and

odo

ur t

hres

hold

s.

Not

a h

ealth

ris

k, e

xcep

t fo

r ha

emod

ialy

sis

patie

nts,

whe

re

wat

er c

onta

inin

g m

onoc

hlor

amin

e sh

ould

not

be

used

for

dial

ysis

. Can

be

rem

oved

by

GA

C fi

ltrat

ion

in d

ialy

sis

units

Mon

ochl

oram

ine

is t

oxic

to fi s

h.

Nitr

ate

and

Nitr

iteBo

th a

re c

omm

on in

sou

rce

wat

er a

t re

lativ

ely

low

con

cent

ratio

ns.

Hig

her

conc

entr

atio

ns m

ay r

esul

t fr

om in

tens

ive

farm

ing

or s

ewag

e effl u

ent

disp

osal

with

in a

cat

chm

ent.

Nitr

ite is

als

o a

brea

kdow

n pr

oduc

t of

ch

lora

min

e.

Whe

re n

itrat

e or

nitr

ate

is li

kely

to

be a

pro

blem

, the

y sh

ould

be

mon

itore

d re

gula

rly.

Nitr

ate

leve

ls a

bove

50

mg/

L (a

s ni

trat

e) m

ay c

ause

adv

erse

he

alth

effe

cts

in b

ottle

fed

infa

nts.

Nitr

ate

is n

ot a

hea

lth t

hrea

t in

itse

lf, h

owev

er it

can

eas

ily

redu

ce t

o ni

trite

in lo

w o

xyge

n co

nditi

ons.

Nitr

ite c

ause

s th

e ox

idat

ion

of h

aem

oglo

bin

to a

form

whi

ch

cann

ot c

arry

oxy

gen

arou

nd t

he b

ody.

Preg

nant

wom

en a

nd

infa

nts

are

mos

t su

scep

tible

to

this

.


111

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Org

anic

D

isin

fect

ion

B

ypro

du

cts

Chl

oroa

cetic

Aci

dsPr

oduc

ed a

s a

bypr

oduc

t of

the

re

actio

n be

twee

n ch

lori

ne a

nd h

umic

/ f

ulvi

c ac

ids

(aci

ds r

esul

ting

from

de

cayi

ng p

lant

/ an

imal

mat

eria

l).

Reg

ular

mon

itori

ng o

f chl

oroa

cetic

aci

d co

ncen

trat

ions

is

diffi

cult.

How

ever

, one

app

roac

h is

to

min

imse

its

form

atio

n by

re

mov

ing

orga

nic

mat

eria

l fro

m t

he w

ater

bef

ore

disi

nfec

tion.

A

noth

er a

ppro

ach

is t

o us

e al

tern

ativ

e di

sinf

ecta

nts

such

as

chlo

rine

dio

xide

.

Long

ter

m e

xpos

ure

to c

hlor

oace

tic a

nd t

rich

loro

acet

ic a

cids

co

uld

pote

ntia

lly c

ause

adv

erse

hea

lth e

ffect

s bu

t lit

tle r

esea

rch

has

been

car

ried

out

.

Dic

hlor

oace

tic a

cid

is u

sed

as a

dru

g to

con

trol

blo

od s

ugar

and

re

duce

cho

lest

erol

.

Trih

alom

etha

nes

(TH

M’s)

Prod

uced

as

a by

prod

uct

of t

he

reac

tion

betw

een

chlo

rine

or

chlo

ram

ine

and

hum

ic /

fulv

ic a

cids

(a

cids

res

ultin

g fr

om d

ecay

ing

plan

t /

anim

al m

ater

ial).

Mon

itori

ng t

riha

lom

etha

ne c

once

ntra

tions

is d

iffi c

ult.

How

ever

, on

e ap

proa

ch is

to

min

imse

its

form

atio

n by

rem

ovin

g or

gani

c m

ater

ial f

rom

the

wat

er b

efor

e di

sinf

ectio

n.

Alte

rnat

ivel

y, a

diffe

rent

dis

infe

ctan

t co

uld

be u

sed

(eg

chlo

rine

di

oxid

e).

Long

term

exp

osur

e to

hig

h le

vels

of s

ome

trih

alom

etha

nes

have

be

en a

ssoc

iate

d w

ith b

ladd

er c

ance

r an

d w

eakl

y as

soci

ated

with

co

lon

canc

er.


112

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Oth

er

Org

anic

C

om

po

un

ds

Acr

ylam

ide

May

be

pres

ent

as a

n im

puri

ty in

po

lyac

ryla

mid

e us

ed a

s a fl o

ccul

ant

aid.

Mon

itori

ng fo

r ac

ryla

mid

e is

not

req

uire

d be

caus

e its

pre

senc

e in

sig

nifi c

ant

conc

entr

atio

ns is

hig

hly

unlik

ely.

How

ever

, it

shou

ld

be t

este

d fo

r di

rect

ly if

its

pres

ence

is s

uspe

cted

.

Hig

h do

se, s

hort

ter

m e

xpos

ure

may

cau

se c

onfu

sion

, di

sori

enta

tion,

mem

ory

dist

urba

nces

, and

hal

luci

natio

ns.

Long

ter

m e

xpos

ure

may

cau

se s

kin

irri

tatio

n, fa

tigue

, and

se

nsor

y ch

ange

s.

Benz

ene

Benz

ene

cont

amin

atio

n w

ill o

ccur

if

wat

er is

con

tam

inat

ed w

ith p

etro

l, or

by

atm

osph

eric

dep

ositi

on fr

om

vehi

cle

exha

ust

emis

sion

s.

Mon

itori

ng o

f ben

zene

con

cent

ratio

n is

onl

y re

quir

ed if

its

pres

ence

is s

uspe

cted

.Ex

posu

re t

o be

nzen

e ha

s be

en a

ssoc

iate

d w

ith le

ukae

mia

.

Car

bon

Tetr

achl

orid

eM

ay b

e pr

esen

t as

an

impu

rity

in

chlo

rine

use

d fo

r di

sinf

ectio

n or

in

wat

er b

y im

prop

er in

dust

rial

was

te

disp

osal

.

Mon

itori

ng is

onl

y re

com

men

ded

if its

pre

senc

e is

sus

pect

ed.

Car

bon

tetr

achl

orid

e m

ay b

e to

xic

to t

he li

ver

and

kidn

eys,

and

pote

ntia

lly a

ffect

cen

tral

ner

vous

sys

tem

dep

ress

ion.

Chr

onic

ex

posu

re m

ay r

egis

ter

as g

astr

oint

estin

al u

pset

s.

Chl

orob

enze

neC

hlor

oben

zene

is a

n in

dust

rial

sol

vent

. It

s pr

esen

ce in

dri

nkin

g w

ater

will

be

the

res

ult

of in

dust

rial

spi

lls o

r di

scha

rges

.

Mon

itori

ng is

onl

y re

com

men

ded

if its

pre

senc

e is

sus

pect

ed.

Lim

ited

data

indi

cate

s th

at c

hlor

oben

zene

is p

oten

tially

tox

ic

to t

he li

ver

and

kidn

eys,

and

may

cau

se c

entr

al n

ervo

us s

yste

m

depr

essi

on.

Dic

hlor

oben

zene

s (D

CB’

s)W

ides

prea

d in

the

env

iron

men

t.

May

ent

er w

ater

thr

ough

impr

oper

w

aste

dis

posa

l or

indu

stri

al s

pills

.

Use

d as

inse

ctic

ide

fum

igan

t an

d as

a

deod

oran

t an

d sa

nitiz

er. E

nter

s vi

a gr

ound

wat

er.

Mon

itori

ng is

onl

y re

com

men

ded

if its

pre

senc

e is

sus

pect

ed.

Chr

onic

, hig

h do

ses

of D

CB’

s ca

uses

live

r an

d ki

dney

dam

age

in

labo

rato

ry a

nim

als.

DC

B’s

have

a t

aste

and

odo

ur t

hres

hold

muc

h lo

wer

tha

n th

e to

xici

ty t

hres

hold

, so

peop

le a

re n

ot li

kely

to

drin

k hi

ghly

co

ntam

inat

ed w

ater

.

Dic

hlor

oeth

enes

(DC

E’s)

May

ent

er w

ater

thr

ough

indu

stri

al

spill

s an

d di

scha

rges

.M

onito

ring

is o

nly

reco

mm

ende

d if

its p

rese

nce

is s

uspe

cted

.In

hale

d di

chlo

roet

hene

s in

hig

h do

ses

may

cau

se c

entr

al

nerv

ous

syst

em d

epre

ssio

n.

Dic

hlor

oeth

enes

are

pot

entia

lly c

arci

noge

nic.

Ethy

lben

zene

May

ent

er w

ater

thr

ough

indu

stri

al

spill

s an

d di

scha

rges

.M

onito

ring

is o

nly

reco

mm

ende

d if

its p

rese

nce

is s

uspe

cted

.Li

mite

d da

ta s

ugge

sts

that

eth

ylbe

nzen

e m

ay c

ause

dam

age

to

the

liver

and

kid

neys

at

high

dos

es.

Ethy

lben

zene

has

a lo

w t

aste

and

odo

ur t

hres

hold

, so

peop

le

are

not

likel

y to

dri

nk h

ighl

y co

ntam

inat

ed w

ater

.

Plas

ticis

ers

DEH

P an

d D

EHA

are

com

mon

ly

used

pla

stic

iser

s in

PV

C p

rodu

cts.

May

ent

er w

ater

aft

er lo

ng t

erm

co

ntac

t w

ith fl

exib

le P

VC

, or

thro

ugh

indu

stri

al s

pills

or

disc

harg

es.

Mon

itori

ng is

onl

y re

com

men

ded

if its

pre

senc

e is

sus

pect

ed.

Long

ter

m e

xpos

ure

may

cau

se li

ver

prob

lem

s, or

rep

rodu

ctiv

e pr

oble

ms.

DEH

P is

pot

entia

lly c

arci

noge

nic.


113

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Poly

cycl

ic A

rom

atic

H

ydro

carb

ons

(PA

H’s)

PAH

’s ar

e co

mm

on in

the

en

viro

nmen

t, fo

rmed

usu

ally

by

the

com

bust

ion

of fo

ssil

fuel

s or

woo

d.

May

ent

er w

ater

thr

ough

atm

osph

eric

de

posi

tion

or le

achi

ng fr

om

bitu

min

ous

liner

s in

dis

trib

utio

n sy

stem

s.

Mon

itori

ng is

onl

y re

com

men

ded

if its

pre

senc

e is

sus

pect

ed.

Lim

ited

evid

ence

sug

gest

s th

at m

any

PAH

’s m

ay b

e po

tent

ially

ca

rcin

ogen

ic.

Tolu

ene

May

ent

er w

ater

thr

ough

indu

stri

al

spill

s an

d di

scha

rges

, par

ticul

arly

fr

om o

il refi n

erie

s. U

sual

ly fo

und

in

grou

ndw

ater

Mon

itori

ng is

onl

y re

com

men

ded

if its

pre

senc

e is

sus

pect

ed.

Inha

latio

n of

tol

uene

cau

ses

impa

irm

ent

of t

he c

entr

al n

ervo

us

syst

em, i

rrita

tion

of t

he m

ucou

s m

embr

anes

, fat

igue

and

dr

owsi

ness

. Ver

y lit

tle e

xpos

ure

wor

k do

ne fo

r in

gest

ion

with

w

ater

.

Tric

hlor

oeth

ylen

e (T

CE)

May

ent

er w

ater

thr

ough

indu

stri

al

spill

s an

d di

scha

rges

, or

from

at

mos

pher

ic c

onta

min

atio

n of

rai

nfal

l.

Mon

itori

ng is

onl

y re

com

men

ded

if its

pre

senc

e is

sus

pect

ed.

TC

E is

a k

now

n de

pres

sant

, and

has

bee

n us

ed a

s an

an

aest

hetic

. Lon

g te

rm e

xpos

ure

can

caus

e liv

er, n

ervo

us s

yste

m

and

circ

ulat

ory

syst

em d

amag

e.

Vin

yl C

hlor

ide

Vin

yl c

hlor

ide

is u

sed

indu

stri

ally

in

the

prod

uctio

n of

PV

C. I

t m

ay e

nter

w

ater

thr

ough

indu

stri

al s

pills

, or

thro

ugh

leac

hing

from

PV

C p

ipes

an

d so

lven

ts u

sed

in c

lean

ing

and

degr

easi

ng m

etal

s.

Leac

hing

from

PV

C p

ipes

is u

nlik

ely

in A

ustr

alia

, sin

ce t

here

are

st

ring

ent

requ

irem

ents

set

for

resi

dual

vin

yl c

hlor

ide

leve

ls in

PV

C p

ipes

and

fi tt

ings

. Thu

s, m

onito

ring

is o

nly

requ

ired

if it

s pr

esen

ce is

sus

pect

ed.

Vin

yl c

hlor

ide

is a

nar

cotic

age

nt a

nd is

car

cino

geni

c w

hen

inha

led.

No

info

rmat

ion

is a

vaila

ble

on it

s ef

fect

s w

hen

inge

sted

.

Xyl

enes

May

ent

er w

ater

thr

ough

indu

stri

al

spill

s, pa

rtic

ular

ly fr

om o

il refi n

erie

s, an

d al

so fr

om a

dhes

ives

use

d to

bon

d pl

astic

dri

nkin

g w

ater

fi tt

ings

.

Mon

itori

ng is

onl

y re

com

men

ded

if its

pre

senc

e is

sus

pect

ed.

How

ever

, it

is r

eadi

ly b

iode

grad

ed in

sur

face

wat

er a

nd

vola

tilis

es t

o ai

r qu

ickl

y, m

akin

g an

y es

timat

e of

con

cent

ratio

n in

su

rfac

e w

ater

unr

elia

ble.

Xyl

enes

may

pot

entia

lly c

ause

ner

vous

sys

tem

dam

age

at h

igh

conc

entr

atio

ns, b

ut t

he t

aste

and

odo

ur t

hres

hold

is m

uch

low

er, s

o pe

ople

are

not

like

ly t

o dr

ink

high

ly c

onta

min

ated

w

ater

.


114

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Pe

stic

ide

s

Ald

rin

and

Die

ldri

nA

ldri

n an

d di

eldr

in a

re h

ighl

y ef

fect

ive

inse

ctic

ides

for

soil

base

d pe

sts,

term

ites,

and

woo

d bo

rers

. Ald

rin

mos

tly o

xidi

ses

to d

ield

rin

afte

r a

year

, an

d di

eldr

in b

reak

s do

wn

very

slo

wly

(h

alf l

ife in

soi

l is

5 ye

ars)

.

Whi

lst

no lo

nger

man

ufac

ture

d in

A

ustr

alia

, con

tam

inat

ion

may

occ

ur

due

to t

heir

per

sist

ence

in t

he

envi

ronm

ent.

Mon

itori

ng is

onl

y re

com

men

ded

if al

drin

was

pre

viou

sly

used

in a

cat

chm

ent.

As

diel

drin

dec

ays,

mon

itori

ng w

ill

beco

me

less

impo

rtan

t in

futu

re.

Rel

ativ

ely

high

dos

es o

f ald

rin

and

diel

drin

are

neu

roto

xic.

How

ever

, al

drin

and

die

ldri

n ac

cum

ulat

e in

the

bod

y, so

eve

n ve

ry lo

w d

oses

ov

er a

long

per

iod

of t

ime

may

eve

ntua

lly b

ecom

e ne

urot

oxic

.

Atr

azin

eH

erbi

cide

use

d fo

r cr

op w

eed

cont

rol

and

fore

stry

, con

tam

inat

ion

may

occ

ur

thro

ugh

runo

ff fr

om a

ffect

ed a

reas

.

Reg

ular

mon

itori

ng is

rec

omm

ende

d if

atra

zine

is b

eing

us

ed in

a c

atch

men

t.Li

mite

d da

ta in

dica

tes

that

atr

azin

e m

ay c

ause

car

diov

ascu

lar

prob

lem

s, an

d m

ay b

e po

tent

ially

car

cino

geni

c.

Chl

orda

neU

sed

as a

bro

ad s

pect

rum

inse

ctic

ide

for

use

in p

rote

ctin

g w

oode

n st

ruct

ures

. C

hlor

dane

is n

o lo

nger

us

ed in

Aus

tral

ia.

Con

tam

inat

ion

may

occ

ur t

hrou

gh

runo

ff of

affe

cted

are

as, w

here

by it

at

tach

es t

o na

tura

l sed

imen

ts o

r is

in

gest

ed b

y aq

uatic

org

anis

ms.

Chl

orda

ne is

hig

hly

resi

stan

t to

de

grad

atio

n.

Reg

ular

mon

itori

ng is

rec

omm

ende

d if

chlo

rdan

e ha

s pr

evio

usly

bee

n us

ed in

a c

atch

men

t.R

elat

ivel

y hi

gh d

oses

of c

hlor

dane

are

neu

roto

xic.

How

ever

, ch

lord

ane

accu

mul

ates

in t

he b

ody,

so e

ven

very

low

dos

es o

ver

a lo

ng p

erio

d of

tim

e m

ay e

vent

ually

bec

ome

neur

otox

ic.

It is

sug

gest

ed t

hat

chlo

rdan

e m

ay a

lso

caus

e liv

er d

amag

e.

2,4-

D(2

,4 –

dic

hlor

o-ph

enox

yace

tic a

cid)

Use

d fo

r br

oadl

eaf a

nd a

quat

ic w

eed

cont

rol,

cont

amin

atio

n m

ay o

ccur

th

roug

h ru

noff

from

affe

cted

are

as.

Reg

ular

mon

itori

ng is

req

uire

d if

2,4-

D is

bei

ng u

sed

in a

ca

tchm

ent.

Lim

ited

data

indi

cate

s th

at 2

,4-D

may

pot

entia

lly b

e ca

rcin

ogen

ic.

DD

T a

nd it

s de

riva

tives

Use

d as

a c

onta

ct in

sect

icid

e. D

DT

is

no lo

nger

use

d in

Aus

tral

ia.

Con

tam

inat

ion

may

occ

ur t

hrou

gh

was

hoff

of a

ffect

ed a

reas

, as

DD

T

read

ily a

ttac

hes

to s

oil a

nd c

lay

part

icle

s.

DD

T is

hig

hly

resi

stan

t to

deg

rada

tion.

Reg

ular

mon

itori

ng is

rec

omm

ende

d if

DD

T w

as p

revi

ousl

y us

ed in

a c

atch

men

t.Ve

ry h

igh

dose

s w

ill c

ause

nau

sea,

vom

iting

, and

men

tal d

istu

rban

ce.

Long

ter

m e

xpos

ure

may

cau

se d

amag

e to

the

live

r an

d ce

ntra

l ne

rvou

s sy

stem

.


115

Co

nta

min

ant

Occ

urr

en

ceIn

dic

ato

rs /

Mo

nit

ori

ng

Po

ssib

le E

ffe

cts

Hep

tach

lor

and

Hep

tach

lor

Epox

ide

Use

d as

bro

ad s

pect

rum

inse

ctic

ide.

H

epta

chlo

r is

no

long

er u

sed

in

Aus

tral

ia.

Con

tam

inat

ion

may

occ

ur t

hrou

gh

runo

ff fr

om a

ffect

ed a

reas

.

Hep

tach

lor

is p

ersi

sten

t in

soi

ls,

but

slow

ly o

xidi

ses

to h

epta

chlo

r ep

oxid

e w

hich

is h

ighl

y re

sist

ant

to

degr

adat

ion.

Reg

ular

mon

itori

ng is

rec

omm

ende

d if

hept

achl

or w

as

prev

ious

ly u

sed

in a

cat

chm

ent.

Long

ter

m e

xpos

ure

may

cau

se d

amag

e to

the

live

r an

d ce

ntra

l ne

rvou

s sy

stem

.

Hep

tach

lor

is p

roba

bly

carc

inog

enic

.

Lind

ane

Use

d as

an

inse

ctic

ide

in a

gric

ultu

re

and

fore

stry

and

for

trea

tmen

t of

he

ad li

ce. L

inda

ne c

an e

nter

wat

er

thro

ugh

runo

ff of

affe

cted

are

as.

Som

etim

es fo

und

in g

roun

dwat

er

Reg

ular

mon

itori

ng is

rec

omm

ende

d if

linda

ne is

bei

ng u

sed

in a

cat

chm

ent.

Lind

ane

is h

ighl

y ne

urot

oxic

. Lon

g te

rm e

xpos

ure

caus

es d

amag

e to

th

e ce

ntra

l ner

vous

sys

tem

and

may

cau

se li

ver

dam

age.

Re

fere

nce

s:N

HM

RC

, NR

MM

C

(200

3)

Aust

ralia

n D

rinki

ng W

ater

Gui

delin

es.

Nat

iona

l Hea

lth a

nd M

edic

al R

esea

rch

Cou

ncil,

Nat

ural

Res

ourc

e M

anag

emen

t M

inis

teri

al C

ounc

il, C

anbe

rra.

ww

w.h

ealth

.gov

.au/

nhm

rcD

e Z

uane

J (1

997)

Han

dboo

k of

Dri

nkin

g Wat

er Q

ualit

y 2nd

Ed

Van

Nos

tran

d R

einh

old

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