FINAL Surface Water Assessment

Karuah East Pty Ltd

November 2012

HQP05-011

FINAL

Surface Water Assessment

Hard Rock Quarry, Karuah East, NSW

Karuah East Hard Rock Quarry

Surface Water Assessment Table of Contents

GSS Environmental November 2012 ii

TABLE OF CONTENTS 1.0 INTRODUCTION .......................................................................................................................... 1

1.1 Project Overview .......................................................................................................................... 1

1.2 Methodology and Scope of this Report ........................................................................................ 1

1.3 Study Area .................................................................................................................................... 2

1.4 Objectives ..................................................................................................................................... 2

2.0 DIRECTOR-GENERAL’S REQUIREMENTS .............................................................................. 3

3.0 EXISTING SURFACE WATER ENVIRONMENT ........................................................................ 5

3.1 Rainfall / Climate .......................................................................................................................... 5

3.2 Landform ...................................................................................................................................... 5

3.3 Vegetation .................................................................................................................................... 5

3.4 Surrounding Land Uses ................................................................................................................ 6

3.5 Soils / Geology ............................................................................................................................. 6

3.6 Surface Hydrology ........................................................................................................................ 7

3.6.1 Regional Hydrology ........................................................................................................... 7

3.6.2 Local Hydrology ................................................................................................................. 7

3.7 Existing Surface Water Quality and Assessment Criteria .......................................................... 11

3.8 Existing Flow Regimes ............................................................................................................... 13

3.9 Surface Water Features of Conservation Significance .............................................................. 13

4.0 RELEVANT LEGISLATION, POLICY AND GUIDELINES ....................................................... 14

4.1 Introduction ................................................................................................................................. 14

4.2 Legislation .................................................................................................................................. 14

4.2.1 Water Act 1912 and Water Management Act 2000 ........................................................ 14

4.2.2 Protection of the Environment Operations Act 1997 ....................................................... 14

4.2.3 State Environmental Planning Policy (SEPP) 14 – Coastal Wetlands ............................ 14

4.3 Policies and Guidelines .............................................................................................................. 15

4.3.1 Hunter – Central Rivers Catchment Action Plan ............................................................. 15

4.3.2 NSW Water Quality and River Flow Objectives .............................................................. 16

4.3.3 ANZECC Guidelines ........................................................................................................ 16

4.3.4 Managing Urban Stormwater .......................................................................................... 17

4.3.5 NSW State Rivers and Estuaries Policy .......................................................................... 17

4.3.6 NSW Farm Dams Policy.................................................................................................. 17

4.3.7 NSW Office of Water – Guidelines for Riparian Corridors (controlled activities) ............ 18

5.0 SURFACE WATER IMPACTS AND PROPOSED MANAGEMENT MEASURES ................... 19

5.1 Introduction ................................................................................................................................. 19

5.2 Objectives ................................................................................................................................... 19

5.3 Proposed Water Management System ...................................................................................... 19

5.3.1 Introduction ...................................................................................................................... 19



GSS Environmental November 2012 iii

5.3.2 Quarry Extraction Area .................................................................................................... 20

5.3.3 Crushing Plant ................................................................................................................. 20

5.3.4 Product Stockpiles and Office Infrastructure Area .......................................................... 21

5.3.5 Surface Water Management – Final Landform ............................................................... 21

5.4 Summary of Proposed Dams and Dam Design ......................................................................... 21

5.4.1 Management and Maintenance of Dams ........................................................................ 22

5.5 Water Sources ............................................................................................................................ 23

5.6 Drainage Lines ........................................................................................................................... 23

5.6.1 Impacts ............................................................................................................................ 23

5.6.2 Mitigation Measures ........................................................................................................ 23

5.7 Licensing Requirements ............................................................................................................. 24

5.7.1 Maximum Harvestable Right Dam Capacity ................................................................... 24

5.7.2 Dirty Water Dams ............................................................................................................ 25

5.7.3 Licensed Discharge Points .............................................................................................. 25

5.8 Cumulative Impacts .................................................................................................................... 25

6.0 SITE WATER BALANCE ........................................................................................................... 26

6.1 Introduction ................................................................................................................................. 26

6.2 The Model ................................................................................................................................... 26

6.3 Water Sources (Model Inputs) .................................................................................................... 26

6.3.1 Rainfall Runoff ................................................................................................................. 26

6.3.2 Groundwater .................................................................................................................... 27

6.3.3 Other................................................................................................................................ 27

6.4 Water Losses and Usage (Model Outputs) ................................................................................ 27

6.4.1 Evaporation ..................................................................................................................... 27

6.4.2 Water Usage ................................................................................................................... 28

6.4.3 Site Discharges ............................................................................................................... 29

6.5 Storages ..................................................................................................................................... 29

6.6 Water Balance Results ............................................................................................................... 30

6.6.1 Scenario 1 – Stage 2 ....................................................................................................... 30

6.6.2 Scenario 2 – Stage 5 Full Extraction ............................................................................... 34

6.7 Sensitivity Analysis ..................................................................................................................... 38

6.8 Conclusions ................................................................................................................................ 39

6.9 Recommendations ...................................................................................................................... 39

7.0 SITE WATER MANAGEMENT PLAN ....................................................................................... 41

8.0 SURFACE WATER MONITORING PROGRAM ....................................................................... 42

8.1 Introduction ................................................................................................................................. 42

8.2 Baseline Data ............................................................................................................................. 42

8.3 Surface Water Monitoring Parameters and Impact Assessment Criteria ................................... 42

8.4 Monitoring Locations .................................................................................................................. 43



GSS Environmental November 2012 iv

8.5 Reporting of Monitoring Data ..................................................................................................... 44

9.0 CONCLUSION ........................................................................................................................... 45

10.0 REFERENCES ........................................................................................................................... 46

APPENDIX Appendix 1 – Water Balance Sensitivity Analysis

TABLES Table 1 - Summary of DGRs relevant to Surface Water Assessment ........................................................ 3

Table 2 - Summary of EARs relevant to Surface Water Assessment ........................................................ 3

Table 3 - Annual Rainfall Statistics (BOM station No. 61072) .................................................................... 5

Table 4 – Results of Baseline Water Quality Sampling ............................................................................ 12

Table 5 – Livestock Water Supply Guidelines for Uncontrolled Streams in the Karuah Great Lakes Catchment ................................................................................................................................................. 16

Table 6 - Key Default Trigger Values for Slightly Disturbed Lowland South East Australian Rivers (ANZECC 2000) ........................................................................................................................................ 17

Table 7 - Catchment Areas of the Study Area .......................................................................................... 20

Table 8 – Summary of proposed dams ..................................................................................................... 21

Table 9 - Predicted Water Usage.............................................................................................................. 28

Table 10 - Water Storages (assumed within water balance model) ......................................................... 29

Table 11 – Indicative Water Balance Results for Stage 2 Scenario (Annual Summaries) ....................... 30

Table 12 - Predicted Discharges from Site for Stage 2 Scenario ............................................................. 32

Table 13 – Indicative Water Balance Results for the Stage 5 Scenario (Annual Summaries) ................. 36

Table 14 – Representative Discharges from Site for Stage 5 Scenario – dry, median and wet years ..... 37

Table 15 - ANZECC Trigger Values ......................................................................................................... 42

Table 16 - Proposed Surface Water Monitoring Locations ....................................................................... 44

Table 17 Sensitivity Analysis for Stage 2 - Historical Dry Year (1901) ..................................................... 48

Table 18 Sensitivity Analysis for Stage 2 - Historical Median Year (1968) .............................................. 49

Table 19 Sensitivity Analysis for Stage 2 - Historical Wet Year (1990) .................................................... 50

Table 20 Sensitivity Analysis for Stage 5 - Historical Dry Year (1901) ..................................................... 51

Table 21 Sensitivity Analysis for Stage 5 - Historical Median Year (1968) .............................................. 52

Table 22 Sensitivity Analysis for Stage 5 - Historical Wet Year (1990) .................................................... 53



GSS Environmental November 2012 v

FIGURES Figure 1 – Locality Plan ............................................................................................................................... 1

Figure 2 – Study Area and Existing Surface Water Environment ............................................................... 2

Figure 3 – Proposed Surface Water Management ...................................................................................... 19

Figure 4 – Water Balance Results for Stage 2 Scenario ............................................................................. 31

Figure 5 – Water Balance Results for Stage 2 Scenario – Historical ‘Dry’ rainfall year of 1901 ................. 33

Figure 6 – Water Balance Results for Stage 2 Scenario - Historical ‘Median’ rainfall year of 1968 ............. 33

Figure 7 – Water Balance Results for Stage 2 Scenario - Historical ‘Wet’ rainfall year of 1990 .................. 34

Figure 8 – Water Balance Results for Stage 5 Scenario ............................................................................. 35

Figure 9 – Water Balance Results for Stage 5 Scenario – Historical ‘Dry’ rainfall year of 1901 ................. 37

Figure 10 – Water Balance Results for Stage 5 Scenario - Historical ‘Median’ rainfall year of 1968 ........... 38

Figure 11 – Water Balance Results for Stage 5 Scenario - Historical ‘Wet’ rainfall year of 1990 ................ 38



GSS Environmental November 2012 vi

GLOSARY OF KEY TERMS

DIRTY WATER Surface runoff from disturbed catchments such as the emplacement areas and stockpile areas, which could contain significant concentrations of suspended sediment.

CLEAN WATER Surface runoff from undisturbed catchments relatively undisturbed by extraction processing or related activities.

ASS Acid Sulphate Soils

BMPs Best Management Practices

BOM Bureau of Meteorology

CMA Hunter-Central Rivers CMA

DoPI NSW Department of Planning and Infrastructure

DPI-MR NSW Department of Primary Industries (Mineral Resources)

EA Environmental Assessment

EC Electrical Conductivity

EPBC Act Environment Protection and Biodiversity Conservation Act 1999

EPL Environment Protection Licence

ESCP Erosion and Sediment Control Plan

ESD Ecologically Sustainable Development

GSSE GSS Environmental

KL Kilolitre

km Kilometre

L Litre

LGA Local Government Area

MHRDC Maximum Harvestable Right Dam Capacity

ML Megalitre

m Metre

mm Millimetre

OEH NSW Office of Environment and Heritage

NOW NSW Office of Water

SWMP Site Water Management Plan

SWMonP Surface Water Monitoring Program

TSC Act Threatened Species Conservation Act 1995

TSS Total Suspended Solids

tpa Tonnes per annum

WM Act Water Management Act 2000


Surface Water Assessment Introduction

GSS Environmental November 2012 1

1.0 INTRODUCTION

1.1 Project Overview

GSS Environmental (GSSE) was commissioned by Karuah East Pty Ltd (the proponent) to prepare a Surface Water Assessment for the Karuah East Quarry Project; a proposed hard rock quarry near Karuah, within the Great Lakes Local Government Area (LGA) in NSW.

An existing hard rock quarry currently operates in the area, approximately three kilometres (km) to the north of the township of Karuah, and is located on Branch Lane adjacent to the Pacific Highway. This quarry currently operates under development approval DA 265/2004 and is approved to produce up to 500 000 tonnes per annum (tpa) of andesite basalt material suitable for use as road base, construction aggregate and concrete batching, among various other applications.

Following exploratory works adjacent to the existing approved quarry, additional resource has been identified to the east on land owned by the Proponent. It is proposed that this additional resource would be extracted through the development of the Karuah East Quarry Project (the Project), a standalone operation to the existing quarry.

The Project would comprise the development of a hard rock quarry and associated processing and facilities area to allow the extraction of up to 1.5 million tonnes per annum (mtpa) from a total resource of approximately 29 million tonnes. The general location of the proposed quarry is shown on Figure 1.

The Karuah East Quarry Project is to be assessed as a Major Project under Part 3A of the Environmental Planning and Assessment Act 1979 (EP&A Act). As such, an Environmental Assessment is required to support the application for project approval. This Surface Water Assessment will form part of the Environmental Assessment.

1.2 Methodology and Scope of this Report

The key aspects addressed within the Surface Water Assessment are as follows:

The collation of relevant data, including meteorological (rainfall events), surface water flow regime (water quality and quantity), catchment characteristics, surface water features, and surrounding land uses. Information has been collected from a literature review of the existing Karuah Quarry and NSW government records, as well as from a site inspection undertaken on 19 August 2010 by GSSE;

The identification of the key issues, relevant assessment criteria and constraints relating to surface water;

The proposed surface water management measures to be implemented throughout the Karuah East Quarry Project;

The recommended safeguards and mitigation measures to be implemented to ensure that potential surface water impacts are managed and appropriate criteria are met;

Compilation of a site water balance to assist with assessment of water security and predicted discharges;

Recommendations for ongoing surface water monitoring; and

An assessment of the impacts of the Project on surface water flows within the Study Area (see Section 1.3 below) and the surrounding watercourses.

This document fulfils the requirements detailed in the Director-General’s Requirements (DGRs) relating to the preparation of a Surface Water Assessment, as discussed further in Section 2.0.

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Surface Water Assessment Introduction


1.3 Study Area

The Study Area for this Surface Water Assessment comprises of Lot 12 and Lot 13 of DP 1024564 within the Parish of Carrington, County of Gloucester of the Great Lakes LGA. The extraction area of the quarry will comprise approximately 14.4 ha and will be mostly contained within Lot 12, with the associated processing and facilities area to be located within Lot 13. Together, these two areas comprise the Study Area for the Surface Water Assessment, with all disturbance areas contained within these two allotments.

The Study Area considered by this Surface Water Assessment is wholly within land owned by the Proponent, with the exception of part of the proposed site access which is located on land owned by the NSW Roads and Traffic Authority (RTA).

The Study Area and relevant site boundaries are shown on Figure 2.

1.4 Objectives

The key objectives of surface water management at the Karuah East Quarry, as addressed in this assessment, are as follows:

The prevention of the flow of sediment into watercourses and the flow-on impact of sedimentation on receiving waters, being Bulga Creek to the east and Yalimbah Creek to the west, both of which flow to SEPP 14 wetlands located within the Port Stephens Estuary;

The management of ephemeral watercourses in accordance with the expectations of the relevant government agencies (primarily the NSW Office of Water (NOW)), including the rehabilitation of the lands which will be disturbed as part of the Karuah East Project;

The control of discharges from the site to ensure that all discharges are within acceptable volumetric and water quality criteria;

The onsite detention and treatment of all dirty water captured within the disturbance area; and

To ensure there is sufficient water available to meet site water requirements.

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Figure 2


Surface Water Assessment Director-General’s Requirements


2.0 DIRECTOR-GENERAL’S REQUIREMENTS

The DGRs for the Project were provided in a letter from the former Department of Planning (now the Department of Planning and Infrastructure (DoPI)) on 25 November 2010. Table 1 provides a summary of the DGRs while Table 2 provides a summary of the Environmental Assessment Requirements (EARs) provided by other government agencies relating to surface water. Tables 1 and 2 also indicate where the specific issues have been addressed within this document.

Table 1 - Summary of DGRs relevant to Surface Water Assessment

Agency Details of Requirements Location in

document where addressed

Department of Planning and Infrastructure – DGRs

The Environmental Assessment of the project must include a detailed assessment of the key issues specified below:

Soil and Water - including

a site water balance;

a detailed description of the proposed water management system;

a detailed assessment (including modelling) of potential surface and groundwater impacts of the project; and

contingency strategies containing measures that would be implemented to avoid, minimise and mitigate any potential impacts of the project.

Section 6

Section 5.3

Section 5.6 (Surface water) – See Coffey Geotechnics (2011) for groundwater assessment.

Table 2 - Summary of EARs relevant to Surface Water Assessment



Department of Environment and Climate Change (DECCW)

Water Management

The EA must provide sufficient information to demonstrate that the proposed development can be operated whilst complying with the Protection of the Environment Operations Act 1997, in particular the protection of water quality during construction and operation of the proposed facility.

The methodology, data and assumptions used to design any pollution control works and assess the potential impact of the proposal on water quality (ground and surface waters), must be fully documented and justified.

Section 5.3

Section 5.4

Department of Water and Energy (DWE)

The assessment is required to:

Take into account the objects and water management principles of the Water Management Act 2000 (WMA);

Satisfy any approval/licence requirements under the Water Act 1912 and WMA;

Demonstrate consistency with the rules of any water sharing plan for the locality. (Surface waters are regulated under the Water Sharing Plan for the Karuah River Water Source);

Section 4

Section 4.2 and 5.7

Section 4.2.1


Surface Water Assessment Director-General’s Requirements




Take into account relevant NSW Government policies;

Take into account DWE’s Guidelines for Controlled Activities (February 2008);

Provide water balance details that address site water demands, sourcing a sustainable water supply and water management including on-site water storage and discharge;

Ensure there are adequate mitigating and monitoring requirements to address surface and groundwater impacts and contamination; and

Provide contingency strategies linked to monitoring and rehabilitation plans.

Section 4.3

Section 4.3

Section 6

Section 5

Section 8

Great Lakes Council Runoff water will need to be contained and treated on site prior to discharge to the wider catchment.

The water quality assessment and management will need to address:

The active quarry pit;

Quarry product and top soil stockpiles;

Haul roads and table drains;

Office , storage and maintenance areas;

Rehabilitation areas until effectively stabilised/regenerated.

In addition, it is expected that a water quality monitoring program is provided so that the long term effectiveness of the water treatment strategy can be validated. It is expected that baseline ecological health condition assessment of Yalimbah Creek receiving water will be undertaken and form part of a future monitoring strategy.

Section 5.3

Section 8.1


Surface Water Assessment Existing Surface Water Environment


3.0 EXISTING SURFACE WATER ENVIRONMENT

3.1 Rainfall / Climate

The Study Area is situated in the Karuah River Valley within the temperate climatic zone of eastern Australia. The climate in the region is characterised by humid sub-tropical weather with warm summers and mild winters and no definitive dry season (Bureau of Meteorology (BOM), 2010).

Long term climate statistics have been sourced from the Tahlee (Carrington (Church Street) BOM station (station number 61072), located approximately 4.5 km from the Study Area, which has operated since 1887. Data collected from this station show the highest temperatures occur throughout December, January and February, with the coolest temperatures occurring in July. Autumn, winter and spring are generally mild.

Low pressure systems pass at regular intervals bringing milder temperatures and winds from the southerly quadrant. The climate is also strongly influenced by oceanographic factors due to the close proximity to the coast (BOM, 2010). The climate is also highly variable being influenced by substantial mountain ranges to the west.

Whilst rainfall is reasonably well distributed throughout the year; there is a slight peak in autumn and early winter and marginally lower rainfall in spring. On average, June is the wettest month of the year and September is the driest. Table 3 contains the rainfall statistics for the 10th percentile (dry), 50th percentile (average) and 90th percentile (wet) rainfall years from the Tahlee BOM station.

Table 3 - Annual Rainfall Statistics (BOM station No. 61072)

Statistic Rainfall

10th Percentile (dry year) 829 mm

50th Percentile (median year) 1154 mm

90th Percentile (wet year) 1630 mm

Given the long term data available from the Tahlee BOM station and the location in close proximity to proposed location of the quarry, it was considered suitable for the undertaking of a detailed water balance for the Project, as well as in the design of appropriate sediment and erosion control structures for the site.

3.2 Landform

The Study Area is situated in the Karuah River Basin, on the south east facing slopes of a small mountain up to 150 m AHD and associated ridgeline falling to the south. Regional topography is irregular being defined by isolated mountains and ridges up to 170 m AHD falling steeply to tidal mudflats adjacent to the Karuah River and rolling hills and ridges further from the Port Stephens estuary. Elevations within the Study Area range from 40 – 150 m AHD, with slopes ranging from approximately 4% in the lower areas up to 40% in the upper slopes of the Study Area.

3.3 Vegetation

A Flora and Fauna Assessment was undertaken by RPS Australia East Pty Ltd (RPS) for the Karuah East Quarry Project.

Field surveys conducted as part of this assessment recorded a total of 132 flora species on site. Two of these species are listed as threatened under the NSW Threatened Species Conservation Act 1995 (TSC Act) and the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act); Tetratheca




juncea (Black-eyed Susan) and Grevillea parviflora subsp. parviflora (Small-flower Grevillea). Both these species are listed as vulnerable under the TSC and EPBC Acts.

Field surveys by RPS Ecologists identified a total of four vegetation communities within the site. Three of these, namely Coastal Foothills Spotted Gum Ironbark Forest, Coastal Plains Smooth-barked Apple Woodland, and Blue Gum Gully Forest are not listed as threatened under the TSC Act or the EPBC Act.

One Endangered Ecological Community (EEC) was recorded within the site, being “Swamp Sclerophyll Forest on Coastal Floodplains of the New South Wales North Coast, Sydney Basin and South East Corner Bioregions” as listed in the TSC Act. The current proposal will not require the removal of any of the EEC within the site.

Further details on the vegetation within and surrounding the Study Area are provided in “Ecological Assessment Report – Karuah East Quarry” (RPS, 2011).

3.4 Surrounding Land Uses

The Study Area is located within a predominantly rural environment, and is closely surrounded by forested areas. To the north beyond the edges of this forested area lies predominantly agricultural and grazing lands. The Pacific Highway is situated immediately to the south of the Study Area, beyond which lies an extensive forested area surrounding an adjacent mountain. There are also SEPP 14 listed coastal wetlands and tidal mudflats surrounding Yalimbah and Bulga Creeks adjacent to this mountain, downstream of the Study Area. The Karuah Nature Reserve and Port Stephens – Great Lakes Marine Park are also downstream of the Study Area. The existing Karuah Hard Rock Quarry and processing area is located immediately to the west of the Study Area.

A number of small access trails traverse the Study Area and adjacent lands. There is also an existing powerline easement running north to south following the ridgeline through Lot 13.

The closest urban development lies approximately 3 km to the south east comprising of the suburbs of Carrington, Tahlee and North Arm Cove. These suburbs lie beyond the northern ridgelines of the adjacent mountain and are not within the line of sight of the Study Area.

3.5 Soils / Geology

A Soil Assessment of the Study Area was conducted by GSSE as part of the preparation of the Environmental Assessment for the Project. This assessment identified three soil types within the Study Area; Brown Chromosols, Red Dermosols and Leptic Tenesols.

The Brown Chromosol soil unit generally consists of sandy loams overlying a clay subsoil. These weak to moderately structured soils range from slightly acid to moderately acid at depth and are non-saline. The topsoil and subsoil are non-sodic. These soils cover approximately a third of the Study Area and are present on the lower slopes to the south.

The Red Dermosol soil unit generally consists of dark yellowish brown to yellowish red clay, and are slightly acidic with low fertility. The topsoil and subsoil are sodic to moderately sodic, and are non-saline. These Dermosols exist throughout the site, covering approximately 15% of the Study Area.

The Leptic Tenosol soil unit covers over half of the Study Area, and consists of shallow, moderately drained sandy clay loams which have developed on crests and slopes around the Area. These soils are moderately to slightly acidic, are non-saline and fertility is low to very low, and are predominately in the proposed extraction area for the quarry.

In regional geology terms, the rock being quarried belongs to the Myall Block in the Tamworth Belt of the New England Orogen. The site forms part of what is known as the Nerong Volcanics, which are




carboniferous siliceous volcanic flows of the rhyolitic and dacitic ignimbrites with occasional flows of tuffaceous sandstone and conglomerate.

3.6 Surface Hydrology

3.6.1 Regional Hydrology

The Study Area lies within the Karuah River / Great Lakes catchment which covers an approximate 4 500 km2. The catchment is bordered by the Manning River catchment to the north and the Hunter River to the south and west. The system comprises three major systems including the Karuah River, the Great Lakes system and the Myall River. Major tributaries of the Karuah Great Lakes system includes the Wallamba, Wallingat, Wang Wauk and Coolongolook Rivers which drain to Wallis Lake. The Karuah River flows for approximately 90 km from the foothills of the Barrington Tops mountain range to the Port Stephens estuary, discharging an approximate 1 500 000 ML per year (Department of the Environment, Water, Heritage and the Arts, 2010).

The Karuah and Myall Rivers run roughly parallel within adjacent valleys, reflecting the topographic features of the regional catchment with strong north-south trending ridgelines in the upper catchment. Rolling ridges and floodplains dominate the lower catchment of the Karuah River which is characterised by wide river valleys. The upper reaches of these rivers is dominated by narrow, steep sided valleys and mountainous terrain. The valleys of the Karuah and Myall Rivers rise slowly westward from the coast with elevations reaching up to 800 m in the North West margin of the catchment.

3.6.2 Local Hydrology

The existing surface water environment within and surrounding the Study Area is illustrated on Figure 2.

The Study Area is situated along a ridge top in the upper catchments of both Yalimbah and Bulga Creeks. The catchment divide lies along the ridge top running north-south through the Study Area. Yalimbah Creek lies to the south west of the Study Area, and flows into Port Stephens via SEPP 14 listed wetlands, which are located approximately 1 km downstream of the Study Area, as illustrated on Figure 2. Bulga Creek flows to the east of the Study Area through agricultural land before also flowing into Port Stephens via SEPP 14 listed wetlands, approximately 3.5 km downstream of the Study Area.

The proposed extraction area is characterised by a mostly steep, heavily forested landscape. The majority of this area lies within the Yalimbah Creek catchment draining to the south west, with only a small portion of the area draining to the east and into the Bulga Creek catchment. The land where the office facilities, processing area and stockpiles are proposed for construction comprises mostly open pasture with scattered stands of eucalyptus, and lies within the Bulga Creek catchment.

Three ephemeral first order watercourses (according to the Strahler numbering system) lie within the western half of the Study Area (Lot 12), named ephemeral drainage line 1, 2 and 3 for the purposes of this assessment, as labelled on Figure 3 (refer page 19). These drainage lines meander through the predominantly forested catchment of the area. These drainage lines have an intermittent low flow channel with poorly defined bed and banks, two flowing in a westerly direction, and one to the south west, ultimately joining Yalimbah Creek.

As illustrated in Plate 1, the ephemeral drainage line 1 flowing to the south west is situated on steep rocky country, has no clearly defined bed or bank, and would only convey flow during heavy rainfall events.




Plate 1 – Looking downstream towards upper reaches of ephemeral drainage line 1

An existing farm dam is located on the upper reaches of ephemeral drainage line 2 in Lot 12 (see Plate 2 and Figure 2). Background water quality samples were obtained from this farm dam during the site visit in August 2010, and is discussed further below in section 3.7.

Plate 2 – Existing Farm Dam (Lot 12)

These ephemeral watercourses become second order immediately to the south west of the Study Area and report to existing RTA managed sediment basins adjacent to the Pacific Highway, illustrated in Plate 3.




Plate 3 - RTA managed sediment basin adjacent to the Pacific Highway

Water from these sediment basins passes beneath the Pacific Highway via culverts (refer Plate 4) and flows to Yalimbah Creek via an existing drainage line.

Plate 4 - Flow beneath the Pacific Highway to Yalimbah Creek

A second order ephemeral watercourse lies in the eastern portion of the Study Area (Lot 13) and ultimately reports to Bulga Creek. This second order drainage line comprises a series of poorly defined interconnected low flow channels which meander through a broad flat floodplain comprising riparian vegetation and water dependant plants. Regular ponding was observed within parts of this drainage line at the time of the site inspection, although there was no flow observed in the drainage line (see Plates 5 and 6).




Plate 5 – Existing Second Order Drainage Line in the East of the Study Area

Plate 6 – Existing Second Order Drainage Line in the East of the Study Area

Two existing farm dams are located adjacent to this drainage line (see Plates 7 and 8). These dams appear to have little, if any catchment reporting to them.






3.7 Existing Surface Water Quality and Assessment Criteria

Baseline water quality data was obtained during the GSSE site visit in August 2010. Water sampling was undertaken in accordance with the Australian Guidelines for Water Quality Monitoring and Reporting (PIMC & NRMMC, 2000). Samples were taken from within the second order drainage line in the east of the Study Area and the adjacent farm dam. A sample was also obtained from within the existing farm dam in Lot 12. Results of this preliminary baseline water quality sampling are presented in Table 4.




Table 4 – Results of Baseline Water Quality Sampling

Parameter Unit

Sample Site

ANZECC Guidelines3 Farm Dam – Lot 131

Second Order Drainage Line

Farm Dam – Lot 122

pH (Field) -- 5.92 5.58 6.20 6.5 – 8.5

Conductivity (Field)

uS/cm 51 200 85 125 – 2200

Conductivity (Lab)

uS/cm 67 232 100 125 – 2200

Total Dissolved

Solids mg/L 58 205 174

Total Phosphorus

mg/L 0.04 0.1 0.05 0.025

Ammonia mg/L 0.14 0.15 0.09 0.02

Nitrogen (Nitrate)

mg/L 1.1 0.3 0.7 0.350

Total Hardness

(as CaCO3) mg/L 5 28 14 --

Oil & Grease mg/L <10 <10 <10 --

Arsenic mg/L <0.001 <0.001 <0.001 0.024

Cadmium mg/L <0.0001 0.0001 <0.0001 0.0002

Calcium mg/L <1 3 2 --

Chromium mg/L <0.001 <0.001 0.002 0.001

Copper mg/L 0.002 0.001 0.009 0.0014

Lead mg/L <0.001 0.001 0.002 0.0034

Magnesium mg/L 1 5 2 --

Manganese mg/L 0.011 0.028 0.05 1.9

Nickel mg/L 0.001 0.001 0.002 0.011

Potassium mg/L 3 2 2 --

Sodium mg/L 11 33 13 --

Vanadium Mg/L <0.01 <0.01 <0.01 --

Zinc mg/L 0.013 0.071 0.012 0.0312 1Existing farm dam adjacent the second order ephemeral drainage line within Lot 13 2Existing farm dam located within Lot 12 3 Key default trigger values presented in ANZECC 2000 for slightly disturbed upland rivers in NSW (refer to Section 4.3.3). Heavy metals based on hard water (120-179 mgCaCO3/L)

The results of this water quality sampling indicate that water quality within the catchment is characterised by a slightly low pH and reasonably low conductivity. Ammonia levels were elevated above ANZECC criteria at all sample locations. In addition, nutrient levels (nitrogen and phosphorus) were above ANZECC criteria in both farm dams, with phosphorus levels also high in the second order drainage line; these results most likely reflective of impacts from agricultural activities in the regional area. The rest of the parameters tested were generally within ANZECC guidelines.




3.8 Existing Flow Regimes

All existing drainage lines that report to or lie within the Study Area are ephemeral in nature and do not support permanent flow, although ponding was observed within the second order drainage line in the east of the Study Area and within all existing farm dams visited during the site visit. It is anticipated that the ephemeral drainage lines would support reasonable flow during high rainfall periods.

3.9 Surface Water Features of Conservation Significance

During the site visit conducted in August 2010 it was noted that there was substantial and well established riparian vegetation surrounding the existing ephemeral drainage lines within the Study Area, particularly the second order drainage line within the east of the Study Area. The nature of this riparian vegetation warrants conservation in line with the conservation criteria detailed within the ‘Guidelines for Controlled Activities – Riparian Corridors’. In accordance with these guidelines, a 20m core riparian zone, as well as a 10m vegetated buffer, will be maintained along this water course. This buffer zone is illustrated on Figure 3 (refer page 19).


Surface Water Assessment Relevant Legislation Policy and Guidelines


4.0 RELEVANT LEGISLATION, POLICY AND GUIDELINES

4.1 Introduction

A number of legislative requirements, government policies and guidelines relating to surface water management are applicable to the Project and have been considered in this Surface Water Assessment. The relevant policies, guidelines and legislative requirements are summarised below.

4.2 Legislation

4.2.1 Water Act 1912 and Water Management Act 2000

The Water Act 1912 and Water Management Act 2000 (WM Act) contain provisions for the licensing of water capture and use. If any dams are proposed as part of the water management, consideration must be given to whether the dams need to be licensed. There are currently no new ‘clean’ water dams proposed for the Project. However two new ‘dirty’ water dams (or pollution control dams) are proposed (refer Figure 3). The first, Dam 1, is proposed in the crushing plant area in an area already containing two smaller farm dams. This dam will serve as an erosion and sediment control dam for runoff from the crushing plant area. Water will also be pumped when necessary from the quarry extraction area into Dam 1 for storage, from where water will be sourced for use in operational activities including dust suppression, and hence it is likely this dam will need to be licenced.

The second dam, Dam 2, is to be constructed in the stockpile area. Whilst this dam will primarily be used for pollution control purposes, water may be sourced from this dam for dust suppression purposes on the product stockpiles and in the pug mill. Discussions are therefore recommended with the NOW to confirm licencing requirements for Dam 2.

The Study Area is located within the area to which the Water Sharing Plan for the Karuah River Water Resource (2003) applies. However, as discussed in Section 5.7, the capacity of proposed dams on site in excess of that required for pollution control is within the sites harvestable right, and as such the site is not affected by the rules in the water sharing plan. On this basis, the rules and regulations contained within the Water Sharing Plan do not apply to the Study Area.

A controlled activity approval under the WM Act is typically not required for surface mining activities due to exemptions for Part 3A Major Projects (Section 91 of WM Act). However, the general standards used by the NOW in implementing the WM Act still need to be adhered to. In this regard, any guidelines referred to by the NOW and the feedback provided by departmental officers should be considered. GSSE has considered the ‘Guidelines for Controlled Activities – Riparian Corridors’ and ‘Guidelines for Controlled Activities – In-Stream Works’ for watercourse rehabilitation and riparian zone rehabilitation (see Section 4.3.7).

4.2.2 Protection of the Environment Operations Act 1997

The Protection of the Environment Operations Act 1997 (POEO Act) is relevant to the Project as it contains requirements relating to the prevention of the pollution of waters. In this regard the discharge of water from the Study Area will need to be controlled to an agreed standard to reduce the potential for pollution of the receiving waters. The Proponent will require an Environment Protection Licence (EPL) under the POEO Act for the discharge of waters from site. The location of and provision of the proposed Licenced Discharge Points (LDPs) are discussed further in Section 5.7.3.

4.2.3 State Environmental Planning Policy (SEPP) 14 – Coastal Wetlands

State Environmental Planning Policy (SEPP) 14 provides for the protection and preservation of coastal wetlands in the economic and environmental interests of the state. SEPP 14 wetlands lie on the




downstream reaches of Yalimbah and Bulga Creeks downstream from the Study Area and so special consideration must be given to these wetlands when designing water management infrastructure.

In this regard, conservative design criteria (95th percentile 5 day design storm) has been adopted for the proposed erosion and sediment control dams 1 and 2, which will be located approximately 3.5 km and 1 km upstream of the SEPP 14 wetlands respectively.

4.3 Policies and Guidelines

4.3.1 Hunter – Central Rivers Catchment Action Plan

The Study Area is situated within the area managed by the Lower North Coast Catchment and is managed by the Hunter – Central Rivers Catchment Management Authority (CMA). In July 2006, the Hunter – Central Rivers CMA published the Hunter – Central Rivers Catchment Action Plan (CAP). The CAP identifies catchment issues and sets measurable management targets with respect to land practices and water quality.

The management targets address issues identified as having the most significant impact on the central catchment resources being biodiversity, aquatic health, soil, estuarine health and marine health.

The over-riding objective for mining and extractive industries as detailed by the CAP is:

‘To minimise the impacts of mining and extractive operations on natural resources and ensure appropriate rehabilitation of affected land.’

The CAP also provides a list of principles to guide the achievement of the above objective. The most relevant of these guidelines are:

a. To take every precaution to ensure that surface water flows are not lost or diverted due to subsidence or geological cracking caused by extraction. Where surface water is lost or diverted, offsest or mitigation actions should be provided.

b. A water management plan (WMP) should be completed and approved before the commencement of mining operations. This WMP should apply to the full lifespan of the mine including after closure. The WMP would show how mining will be conducted so that water resources are managed sustainably. Development of the WMP should be open and transparent.

c. Monitoring should be undertaken throughout the life of the project. Environmental monitoring procedures should be open and transparent and reporting to the relevant stakeholders should be part of any extraction activity.

d. Current best practice of mine rehabilitation should ensure that land affected by mining is progressively returned to at least its former productive condition so that it can support appropriate vegetation cover.

e. Adequate buffers should be maintained between mining activities and adjacent surface waters to protect these areas from mining related impacts.

f. Cumulative impact of mining should be considered during the approval process

The CAP states that the underlying principle to achieving many of these targets is through the use of Best Management Practice’s (BMP). The management controls presented in this Surface Water Assessment for the proposed Karuah East Quarry, are based on BMPs, including those presented in the Blue Book.




4.3.2 NSW Water Quality and River Flow Objectives

NSW Water Quality and River Flow Objectives were established by the NSW Government in September 1999 for the majority of NSW catchments. Eleven water quality objectives (WQOs) were developed for NSW rivers and estuaries and these provided guideline levels to assist water quality planning and management. According to the Karuah River and Great Lakes River Flow Objectives, the streams located within and reporting to the Study Area are classified as “Uncontrolled Streams”.

There are numerous WQOs for “Uncontrolled Streams” within the Karuah and Great Lakes catchment depending upon the environmental values within the area. The most relevant of these objectives for the Study Area are as follows:

(a) aquatic ecosystems (maintaining or improving the ecological condition of waterbodies and their riparian zones over the long term);

(b) livestock water supply (protecting water quality to maximise the protection of healthy livestock); and

(c) aquatic foods (cooked) (protecting water quality so that it is suitable for the production of aquatic foods for human consumption and aquaculture activities).

The aquatic ecosystem objective is in-line with the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC 2000) default trigger values for slightly disturbed ecosystems in south-east Australia. These values are presented below in Table 6 in section 4.3.3.

The livestock water supply objective is based on four key indicators. These indicators and their numerical trigger values are summarised below in Table 5.

Table 5 – Livestock Water Supply Guidelines for Uncontrolled Streams in the Karuah Great Lakes Catchment

Indicator Numerical Criteria (trigger values)

Algae and Blue-Green Algae Increased risk when Microcystins >11 500cells/mL and/or >2.3µg/L expressed as microcystin-LR toxicity equivalents

Salinity (electrical conductivity) Recommended concentrations of total dissolved solids in drinking water for livestock are given in table 4.3.1 (ANZECC 2000 Guidelines

Thermotolerant coliforms (faecal coliforms) <100 thermotolerant coliforms per 100 mL (median value)

Chemical contaminants

See Table 4.3.2 of ANZECC Guidelines for heavy metals and metalloids in livestock drinking water

Refer to Australian Drinking Water Guidelines (NHMRC and NRMMC 2004) for information regarding pesticides and other organic contaminants, using criteria for raw drinking water.

The trigger values for livestock water supply are significantly higher than the trigger values for aquatic ecosystems (See Section 4.3.3). The Project is seeking to comply with the more conservative aquatic ecosystem trigger values.

4.3.3 ANZECC Guidelines

Water quality impacts will be assessed for aquatic ecosystems in accordance with the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC, 2000). The watercourses within the site are considered to be ‘slightly disturbed ecosystems’ as described in the ANZECC Guidelines, and the




elevation of the site places the site in the ‘lowland river ecosystem’ category. Whilst ANZECC suggests that less conservative trigger values may be adopted for ‘highly disturbed ecosystems’, this assessment has used the default ANZECC trigger values as a benchmark. Key default trigger values presented in ANZECC 2000 for slightly disturbed upland rivers in NSW are shown below in Table 6.

Table 6 - Key Default Trigger Values for Slightly Disturbed Lowland South East Australian Rivers (ANZECC 2000)

Indicator Trigger Value

pH 6.5 – 8.5

Conductivity (µS/cm) 125 - 2200

Turbidity (NTU) 6 – 50

Total Phosphorus (µg/L) 25

Total Nitrogen (µg/L) 350

Dissolved Oxygen (% saturation) 85 -100%

Aluminium (mg/L) 0.055

Cadmium (mg/L) 0.00021

Copper (mg/L) 0.00141

Lead (mg/L) 0.00341

Nickel (mg/L) 0.0111

Zinc (mg/L) 0.0081

1. Range based on lower 85% saturation limit and typical water temperature range 13- 20oC 2. Trigger values for the slightly disturbed lowland river aquatic ecosystems 3. Modified trigger levels, factored based on typical moderate water hardness (60-119 mg/L as CaCO3)

4.3.4 Managing Urban Stormwater

In NSW, the most relevant and comprehensive guidelines for the designs of stormwater controls relating to mines is contained in Managing Urban Stormwater: Soils and Construction Vol 2E – Mines and Quarries (DECC, 2008) in conjunction with the references to Volume 1 (Landcom, 2004). Both of these references are referred to in this report as the Blue Book. The principles of surface water control, including the design of erosion and sediment control structures, have been adopted where applicable in this Surface Water Assessment.

4.3.5 NSW State Rivers and Estuaries Policy

The NSW State Rivers and Estuaries Policy contains state-wide objectives for the protection and enhancement of watercourses. The proposed surface water management should be consistent with the Policy objectives. The key aspect of this would be to demonstrate that there is no degradation of water quality within Yalimbah or Bulga Creeks as a result of the proposed Karuah East Quarry Project.

4.3.6 NSW Farm Dams Policy

The NSW Farm Dams Policy was introduced in 1999. Under this policy it is not necessary to obtain a licence or other consent from the Office of Environment and Heritage (OEH) for a farm dam provided:

They are not collecting flow from a major stream; and

The combined capacity does not exceed the Maximum Harvestable Rights Dams Capacity (MHRDC) for the property. The MHRDC is addressed in Section 5.7.




4.3.7 NSW Office of Water – Guidelines for Riparian Corridors (controlled activities)

Controlled activities carried out in or on waterfront land are regulated under the Water Management Act 2000 (WM Act). The NOW administers the WM Act and is required to assess the impact of any proposed controlled activity to ensure that no more than minimal harm will be done to waterfront land as a consequence of carrying out the controlled activity. The purpose of establishing riparian corridors aims to protect waterways through:

Providing for bed and bank stability and reducing bank and channel erosion;

Protecting water quality by trapping sediment, nutrients and other contaminants;

Providing diversity of habitat for terrestrial, riparian and aquatic plants (flora) and animals (fauna);

Providing connectivity between wildlife habitats;

Conveying flood flows and controlling the direction of flows; and

Providing an interface or buffer between developments and waterways.

The application of these guidelines to the proposed Karuah East Quarry Project and the recommended establishment of riparian buffer zones are discussed in Section 5.


Surface Water Assessment Surface Water Impacts and Proposed Management Measures


5.0 SURFACE WATER IMPACTS AND PROPOSED MANAGEMENT MEASURES

5.1 Introduction

The following section outlines the anticipated surface water impacts, and the proposed surface water management measures to be implemented for the Project. Water management measures are described for the operational (mining) phase, as well as a brief overview of drainage controls to be implemented on the final landform of the mine site in Section 6.3. The nature of mining proposed at the quarry means that as mining progresses the water management system will remain the same, with just the in pit sump moving within the active quarrying area.

5.2 Objectives

The principle objective of surface water management at the quarry will be to segregate clean and dirty water flows and to minimise surface flows across disturbed areas. The key water management strategies proposed to be adopted across the Study Area to achieve this objective are summarised as follows:

1. Water generated within the active quarry extraction area, primarily as a result of rainfall/runoff, will be managed within the extraction area via an in-pit sump. Water will be directed to and contained within the in-pit sump until it is necessary to pump the water out so as to not impede quarrying activities. This water will be pumped into a rock lined table drain adjacent to the main haul road, from where it will flow via a rock lined drop structure to Dam 1.

2. Dirty water generated from disturbed areas, such as the processing and stockpile areas, as a result of rainfall/runoff will be captured and diverted into sediment dams for reuse in processing activities, or to reduce sediment load prior to discharge if required.

3. As much water as possible collected in the extraction area and/or dirty water dams will be re-used for processing and dust suppression purposes. Water will be preferentially used on-site to minimise the need for offsite discharge and the chance of pollution to downstream waterways.

4. Clean water diversions will be constructed wherever possible upstream of disturbance areas, to minimise the amount of dirty water to be contained and treated within the dirty water management system. It is noted however, that given the location of the quarry at the top of the ridgeline, the need for diversions will be limited.

5. Progressive rehabilitation of all formed surfaces, such as quarry benches and long-term soil stockpiles, will occur wherever possible to help reduce the amount of total suspended solids (TSS) in runoff from disturbed areas. It is noted that given the nature of quarrying these opportunities will be limited, however will be undertaken wherever possible.

6. Sediment control structures will be maintained to ensure the design capacities are maintained for optimum settling rates.

7. Implementation of an effective revegetation, maintenance and monitoring program for the site.

5.3 Proposed Water Management System

5.3.1 Introduction

The proposed water management system for the quarry is based around a number of sediment basins to allow for the capture of dirty water runoff from disturbed areas. This is to allow for the settlement of sediment in the runoff, as well as the collection of dirty water to be re-used for dust suppression and processing activities as required. Two dirty water dams are proposed for the site, Dam 1 and Dam 2, as illustrated on Figure 3. In addition, a small sump will be established within the quarry to capture and temporarily store runoff generated in the active extraction area.

Existing farm dam

BundSediment Fence

12

D.P.1024564

13

D.P.1024564

PP

PP

10 / 7 mm Agg

WB 2

WB 1

WB Office

HEAVYVEHICLES

ONLYMAIN HQ

C/PC/PENTRANCE ROAD

TRUCK

PARKINGOFFICE

WORKSH

OP

FUEL

& OIL

C/PLA

B

WASH

PUGMILL

PLANT

DAM

DAM

ENTRANCE ROAD

20mm Agg20 / 14 mm Agg20 / 14 mm AggDGB20DGB20

20FCR40 FCR40mm Agg

14mm Agg

14mm Agg

10 / 7 mm Agg

10 / 7 mm Agg

Bund

Haul Road

CrushingPlant

ExistingHouse & Shed

Dam 2

Dam 1

SW4

PowerlineEasement

SW2

SW3

In-pit Sump

SW1

1

23

Existing Farm Damsto be Upgraded

ProposedLDP1

ProposedLDP2

Catchment Boundary toRepresent Final Landform

LEGEND

FIGURE 3

Proposed Surface Water Management Plan

To be printed A3

0 200m15010050

Catchment Areas

Lot boundary

Proposed dam

Existing Farm Dam

Existing Drainage line

Riparian corridor

Drop structure

Clean Water Diversion drain

Quarry extraction area (Stage 5)

Crushing plant

Product stockpile and officeinfrastructure area

Proposed Surface Water monitoringpoints.

N:\11819\Third Party\GSSE\2012-09-07\Fg3_HQP05-008_SWPlan_121106_ADWJ.dwg

SW3




For the purposes of the Surface Water Assessment the Study Area has been divided into three main catchments; the quarry extraction area, crushing plant, and stockpiles and office infrastructure. The rest of the Study Area will remain clean water catchments with water flowing offsite. These catchments are illustrated on Figure 3, and summarised in Table 7.

Table 7 - Catchment Areas of the Study Area

Catchment Area (ha)

Quarry extraction area 14.4

Crushing plant and haul road 3.75

Product stockpiles and office infrastructure

8.4

An overview of the proposed water management system proposed for each of these catchment areas, which incorporates mitigation measures to ensure the effective management of surface water on-site and to minimise the risk of any off-site impacts on surface water resources, is provided below. The following sections also describe how these mitigation measures will be specifically applied to the various areas of the Study Area throughout the life of the quarry.

The proposed water management system is illustrated on Figure 3.

5.3.2 Quarry Extraction Area

Runoff generated within the active quarry extraction area will be directed into an in-pit sump where it will be contained and pumped out as required. Given that the quarry is situated at the top of a hill, no upstream catchment will report to the quarry extraction area. In addition, the specialist groundwater report conducted for the quarry (Coffey Geotechnics, 2011), reports that little to no groundwater seepage is expected in the extraction area, and therefore the only runoff to be managed within the quarry is anticipated to be that generated by rainfall/runoff falling directly in the active extraction area.

A bund and sediment fence will be maintained along the southern boundary of the quarry, as illustrated on Figure 3, to minimise the risk of sediment being washed downstream of the quarry.

Construction of the quarry floor will be managed in such a way so as to direct all runoff to the in-pit sump. The location of this sump will change as quarrying progresses, however is anticipated to generally be in the south east corner of the quarry, as illustrated on Figure 3.

Water collected in the in-pit sump will be pumped out as required into a rock lined table drain adjacent to the main haul road. The water will flow down this drain to the main dirty water dam, Dam 1, via a rock lined drop structure, as illustrated on Figure 3. Dam 1 is discussed further below.

5.3.3 Crushing Plant

An existing farm dam is located on the north eastern boundary of the proposed crushing plant area. This dam is located approximately 50m from the centreline of the adjacent drainage line and will be used as a sediment dam for the crushing plant catchment area (Dam 1). This dam is currently a turkey’s nest dam, and therefore some works will be required to ensure runoff from the crushing plant catchment area flows into the dam. The crushing plant area will be graded such that runoff from this area will flow into Dam 1.

Dam 1 will act as the primary dirty water dam for the Study Area to which all water collected on site will eventually be conveyed. Water for haul road dust suppression, as well as for the crushing plant will be sourced from this dam. Further information on water usage is provided in Section 6 – site water balance.




The minimum required capacity of Dam 1 has been estimated in accordance with Blue Book requirements to capture and treat water from the crushing plant catchment area, as well as runoff from the haul road, which will flow to Dam 1 via a rock lined table drain and drop structure. Based on Blue Book calculations, Dam 1 needs to be approximately 4.4 ML. However, given that this dam may also receive water from the in-pit sump in circumstances where the sump needs to be de-watered to allow for continuation of quarry activities, it is recommended that the dam be built with an additional storage capacity above that required by the Blue Book. Based on a design depth of excavation of 2m, 2.5:1 external batters and a dam crest width of 2m, as well as taking into account the MHRDC (refer Section 5.7), the proposed dam capacity is approximately 12.4 ML, giving an additional capacity of approximately 8 ML above Blue Book requirements.

Further details on dam design parameters and assumptions are provided in Section 5.4.

An application for a LDP will be made so that in the event that excess water is required to be discharged from Dam 1, this can be done in a controlled manner. Further detail on the LDP and anticipated discharge events is provided in Section 6 Site Water Balance.

A diversion bund will be constructed along the eastern boundary of this catchment area, as illustrated on Figure 3, to direct runoff from the area into Dam 1.

5.3.4 Product Stockpiles and Office Infrastructure Area

A second sediment dam, Dam 2, will be constructed adjacent to the main haul road to capture runoff from this area, as illustrated on Figure 3. Water collected in Dam 2 may be re-used for dust suppression on the product stockpiles and in the pug mill.

5.3.5 Surface Water Management – Final Landform

Dams 1 and 2 are planned to remain in place for post-mining landuse (such as farming practices) subject to consultation with the relevant government agencies about the licensing conditions at the time. If required, the dams will be removed so that water use rights are complied with.

5.4 Summary of Proposed Dams and Dam Design

The required volumes for the proposed sediment dams were calculated following the guidelines and procedures presented in Volume 1 and 2E (Mines and Quarries) of the Blue Book for the minimum criteria for Type D/F sediment dams.

Table 8 – Summary of proposed dams

Dam Sediment Zone (ML)

Settling Zone (ML)

Additional water storage capacity (ML)

Total Capacity (ML)

Dam 1 (crushing plant) 1.3 3.1 8 12.4

Dam 2 (stockpile area) 0.9 4.3 0 5.2

The general parameters used in the design of proposed Dams 1 and 2 are presented below.

Design Storm of 5 Days, 95th Percentile – based on the design criteria presented in Table 6.1 of Volume 2E (Mines and Quarries) of the Blue Book, which recommends adopting a 95th percentile design storm event when designing a Type D/F basin where the duration of disturbance will be greater than 3 years. For the Karuah region, the 5 day, 95th percentile rainfall depth is 90.6 mm. This conservative criteria has also been adopted given the proximity of SEPP 14 wetlands to the Study Area.




Volumetric Runoff Coefficient of 0.79 – this reflects the Blue Book soil hydrologic group D which has a very high runoff potential. Group D soils are fine-textured (clay) and are surface sealed. The coefficient is also in line with the default runoff characteristic presented in Volume 2E (Mines and Quarries), which recommends using soil hydraulic group D in the absence of site-specific data.

Soil Classification of Type D (dispersive) – The soil survey undertaken for the site (GSSE, 2011) found some soils within the Study Area to be dispersive, and therefore the sediment basins have been conservatively designed with all soils classified as dispersive.

Soil Erodibility Factor (K factor) of 0.05 - based on the conservative default criteria presented in the Blue Book.

Rainfall Erosivity Factor of 2750 – based on Study Area’s location on the rainfall erosivity maps presented in Appendix B of Volume 1 of the Blue Book.

A conservative ground cover management factor (C-factor) was adopted for the calculation of the anticipated sediment storage zones for the basins (based on anticipated percentage ground cover). The ground cover for the catchment areas of the dams was assumed to be 0%, given that the areas reporting to the dams will be highly disturbed.

5.4.1 Management and Maintenance of Dams

The required capacity for the sediment dams is based on the assumption that the water within the settling zone (as reported in Table 8) will be pumped out within 5 days of a rain event. This will allow for maximum storage of runoff when the next rainfall event occurs and minimises the chances of an uncontrolled discharge off-site.

In the event that water is required to be released offsite, the water will be tested prior to controlled release to ensure appropriate discharge criteria are met, such as Total Suspended Solids (TSS) below a concentration of 50mg/L. Where this is not the case, water will be treated, for example through the use of chemical flocculation, to achieve a suitable water quality. There are various other methods and techniques available to remove solids from sediment-laden water and the most appropriate will be determined for use on a case by case basis in conjunction with specialists and relevant government agencies.

Flocculants that may be used include alum, gypsum or synthetic flocculants such as polyacrylamide. All have particular environmental constraints, but all are well recognised as useful chemicals for the task of clarifying water prior to discharge to a natural waterway. Due to the low frequency of application and practical needs for operating on a quarry site, the task of flocculating water prior to discharge will likely be conducted by an external contractor. It is recommended that an appropriate mass of flocculant be dissolved in an agitated vessel, transported to site and released into the dam. The final concentration of flocculant should be determined by measuring suspended solid levels and ensuring an adequate dosage is delivered. The prescribed dosage should take into account relevant toxicity levels and other environmental considerations. Water can typically be released to the environment one to two days after flocculation.

An inspection of the sediment dams should be undertaken as part of the routine site environmental inspection program or following significant rainfall. Various information, such as the general condition of the dam, evidence of overflow, condition of downstream catchments, water colour, evidence of eroding surfaces and approximate retained capacity, should be recorded.

It is noted that a detailed design (for construction) of the sediment dams has not been undertaken as part of this assessment, only an assessment of sizing requirements as defined in the Blue Book and an estimate of the maximum dam volume that would fit in the proposed location. Consideration should be given to the operation of the dam and the access requirements for maintenance of the dam during the detailed design, in particular the size requirements of maintenance machinery.




5.5 Water Sources

The majority of water required on the site is for dust suppression activities, including in the crushing process, pug mill, and for dust suppression on the haul roads and product stockpiles. A nominal amount of potable water will be required on-site, and will be trucked in from an external source.

Water for these operational activities will be sourced preferentially from the sediment dams discussed above in Section 5.4. Where there is insufficient water stored on site to meet operational demands, water may be trucked in from off-site as required.

5.6 Drainage Lines

5.6.1 Impacts

The only disturbance to directly occur to the local drainage system would occur in the upper reaches of the northern most drainage line in Lot 12 (drainage line 1 – refer Figure 3). The extraction area of the quarry when at its maximum disturbance footprint will extend into the upper reaches of this drainage line, which is an ephemeral first order drainage line. In addition, the length of channel which would be disturbed as a result of excavation of the quarry is located in the upper reaches of the catchment with no clearly defined bed or banks. Therefore the impact on the wider catchment as a result of disturbance to the upper reaches of this drainage line is not anticipated to be significant. Notwithstanding this, a number of mitigation measures will be implemented to ensure that impacts are minimised, as described in the section below.

The second order drainage line flowing through Lot 13 will not be directly disturbed by the quarry. However it is anticipated that water would be discharged into this drainage line from Dam 1. Surface water monitoring will therefore be undertaken in this dam to ensure water discharged is of an appropriate water quality, as discussed in Section 8.

With regards to offsite discharges, a water balance model has been developed to predict the frequency and volume of discharges from the Study Area. The water balance predicts that uncontrolled discharges will be minimal, averaging only 3 discharge days a year in Stage 2 (which represents approximately half of the total disturbance area) discharging a total of 7 ML, and 6 days in Stage 5 (at full disturbance) discharging a total of 14 ML over the year. In addition, controlled releases will also occur over approximately 19 days during Stage 2, and 33 days per year in Stage 5. The outcomes of the water balance are presented in detail in Section 6.

Importantly with regards to impacts on water quality, as can be seen from the water balance results the majority of discharges from the quarry will be as a result of controlled releases. And, as described above in Section 5.4.1, water will be tested prior to controlled release to ensure that appropriate discharge criteria are met.

5.6.2 Mitigation Measures

A sediment fence will be installed along the downstream side of the entire southern face of the quarry as a sediment control measure to minimise the transport of any sediment into the remaining section of the first order drainage line to the south of the extraction area.

It is also proposed that this drainage line be reinstated as close as possible to its original path following completion of extraction activities at the quarry as part of the final rehabilitation of the site. The rehabilitation program would seek to achieve a long-term enhancement of the ecological value of the drainage line through the restoration of natural hydraulic conditions and appropriate revegetation of a riparian corridor.

The Site Water Management Plan (SWMP) for Karuah East will need to include further details on the drainage line rehabilitation works. Works within the restored drainage lines should be generally undertaken in accordance with Section 5.3.3 of the Blue Book (Volume 1) and the ‘Guidelines for Controlled Activities –




In-Stream Works’ (DWE, 2008) for watercourse rehabilitation and riparian zone rehabilitation. Key design elements of channel establishment works include:

Implement effective temporary erosion controls to provide for the short-term stabilisation of the channel;

Design and construct the stream channel so that it would be stable for the long-term and minimises the potential for the migration of any erosion upstream or downstream;

The drainage line should be re-instated as a compound channel with a main channel conveying the small to medium flows, and a floodplain used to convey the high overbank flows;

The main channel forming part of the re-instated central drainage line should be generally trapezoidal in shape with 3:1 (H:V) bank batters;

Natural meanders should be used instead of straight lines to reflect natural stream characteristics;

Where there are high erosive forces (such as high flow velocity or steep grades) the channel bed should be rock lined where required and constructed in accordance with the Blue Book, including the placement of appropriately sized rocks above a filter layer of suitable geotextile; and

Soil should be packed in between rocks to allow sedges and grasses to be established within the channel to provide for long-term channel stability.

Following earthworks and channel establishment, a riparian corridor should be established with a minimum width of 10 m, measured horizontally and at right angles to the flow from the top of both banks on the streams. Key design elements of the riparian corridor establishment include:

Implement effective temporary erosion controls to provide for the short-term stabilisation of the riparian corridor;

Restore a vegetated riparian corridor along the stream channel (10 m from top of bank);

Establish a diverse range of locally occurring vegetation species;

Establish a full range of vegetation types, including trees, shrubs and grass covers;

No exotics species are to be introduced; and

Maintain the rehabilitated riparian corridor for two years after initial rehabilitation.

As discussed above in section 5.6.2, the second order drainage line will not be directly disturbed by the quarry. However it is noted that the associated crushing infrastructure will be installed in close proximity to this drainage line. It is therefore recommended that the works described in the dot points above also be undertaken to enhance the riparian zone along this creek line in Lot 13 to ensure enhanced ecological values are achieved in the riparian zone.

In addition, water from Dam 1 will overflow into this second order drainage line. The water quality will therefore be monitored in Dam 1 as part of the regular surface water monitoring program, as discussed further in section 8, as well as before any planned discharge from this dam. In the event that the water quality is not deemed acceptable for discharge (i.e. TSS limits above ANZECC/EPL limits) then the dam is to be treated, for example through the use of chemical flocculation, to achieve a suitable water quality. Further detail on flocculation is provided above in Section 5.4.1.

5.7 Licensing Requirements

5.7.1 Maximum Harvestable Right Dam Capacity

The maximum dam capacity of the Study Area is determined by the following calculation:

MHRDC = Study Area (ha) x Multiplier Value (0.11)




The MHRDC has been calculated to be approximately 8.2 ML based on the Study Area of 74.3 ha (Lot 12 and Lot 13, both of which are owned by Karuah East).

5.7.2 Dirty Water Dams

All of the proposed dirty water dams (sediment basins) are exempt from harvestable right calculations under the NSW Farm Dams Policy 1999, given that the purpose of the dams is to prevent the contamination of downstream waterways from pollutants such as TSS.

However, it is noted that water from Dam 1 will be used for processing activities, and as such it is likely that this dams may need to be licenced. It is also noted that the combined capacity of the proposed pollution control dams only exceeds the capacity required to treat runoff for erosion and sediment by the maximum harvestable right capacity. Consultation will be undertaken with NOW to ensure their requirements are met with regards to licencing.

5.7.3 Licensed Discharge Points

The results of the water balance, as presented further below in Section 6, indicate that the Karuah East Quarry would need to discharge surface water to the surrounding environment. An application to the NSW OEH for the establishment of LDPs will therefore need to be made as part of the Project.

A LDP is anticipated to be required at the outlets of both Dam 1 and Dam 2. It is recommended however that the controlled release of water, should this be required as part of the appropriate operation of these dams, be preferentially made from Dam 1 rather than Dam 2 given the relative close proximity of the SEPP 14 wetlands downstream of Dam 2. It is recommended therefore that the water management system be set up to allow for water to be pumped from Dam 2 to Dam 1 as required for release. As such it is anticipated that the only discharge of water from Dam 2 would be during extreme wet weather events.

5.8 Cumulative Impacts

As discussed in Section 5.6.2, and in further below Section 6, the predicted uncontrolled discharges following a wet weather event in exceedance of the design criteria are predicted to be minimal, with only 3 discharge days predicted in Stage 2, and 6 in Stage 5, in an average rainfall year. If the proposed surface water management measures as described in this section are followed, particularly in relation to maintenance of the sediment dams, the cumulative impacts of the quarry on water resources in the region are expected to be minimal.


Surface Water Assessment Site Water Balance


6.0 SITE WATER BALANCE

6.1 Introduction

This section examines the site water requirements and available water storage against water availability to present a water balance for the Project. Site water balance calculations were undertaken for two scenarios; scenario 1, which is based on the expected disturbance footprint at Stage 2 of quarry operations (i.e. a quarry footprint of 7.7 hectares which is approximately half the amount of disturbance compared to when the quarry is at full extraction), and scenario 2 assuming maximum disturbance within the proposed quarry footprint. The results are formulated from over 100 years of rainfall data collected in the region and the results are presented for dry, median and wet rainfall conditions.

GSSE used Microsoft Excel to develop a detailed daily time step water balance taking into account the available daily rainfall records for over 100 years of historical data. For the establishment of the water balance model, GSSE assumed generic runoff coefficients using appropriate references (including the Blue Book and Australian Rainfall and Runoff) and previous experience.

The site water balance applies to the whole Study Area, with the exception of the water for the office amenities, as this is trucked to site and is maintained as a separate system from the overall site water management.

6.2 The Model

The water balance model was developed for the full 110 years of available data. An annual summary of this model was produced from which trend-lines were developed. These trends were used to estimate the water balance results for a probable dry year (10th percentile rainfall), median year (50th percentile rainfall) and wet year (90th percentile rainfall).

In addition to the purely statistical analysis the daily results of the water balance were plotted for a historical dry year (10th percentile), median year (50th percentile) and wet year (90th percentile) to show possible variation in inputs/outputs throughout a 12 month period. Where possible, the historical records were selected with preceding years of fairly average rainfall. The years selected as being representative of dry, median and wet years are:

1901 (dry year) – 817.3 mm;

1968 (median year) – 1154.3 mm; and

1990 (wet year) – 1636.8 mm.

6.3 Water Sources (Model Inputs)

6.3.1 Rainfall Runoff

Rainfall

Long term historical rainfall data was sourced from the Tahlee (Carrington, Church Street) BOM station (station number 61072), located approximately 4.5 km from the Study Area, and which has operated since 1887.

110 years (1900 to 2009) of rainfall data was utilised from the Tahlee BOM Station.

The statistical analysis of the data for the Tahlee Station shows:




10th Percentile year (dry year): 829 mm

50th Percentile year (median year): 1154 mm

90th Percentile year (wet year): 1630 mm

Catchment Areas

GSSE delineated between different catchment areas based on runoff characteristics. The following catchments were defined and areas estimated:

Quarry extraction pit, which is assumed to have high runoff;

The crushing plant and haul road Infrastructure area; and

Main entry and product stockpiles and main office area.

These areas are also assumed to be highly disturbed and therefore have high runoff. The catchment areas of the Study Area are illustrated on Figure 3.

It is noted from the list above that no clean water catchments were incorporated into the water balance. The quarry is located on the top of a ridgeline and as a result very little clean water will flow into the Study Area. However, for clean water catchments that do report into the Study Area, clean water diversions will be put into place to divert this water away and prevent it entering the disturbed parts of the Study Area. It is also assumed that all areas within and immediately surrounding the crushing, stockpile and office areas will be disturbed and as such are treated as dirty water catchments in the water balance.

Runoff Coefficients

Rainfall runoff was calculated by estimating an initial loss (in mm), followed by a loss consisting of a constant fraction of the remaining rainfall for that day (as described with Australian Rainfall and Runoff Book 2).

6.3.2 Groundwater

The Groundwater Assessment undertaken by Coffey Geotechnics (2011) found that the typical groundwater RL at the proposed quarry site is greater than 10 m below the planned quarry base. Excavation in the quarry is therefore not anticipated to intersect the groundwater surface. As such, groundwater has not been included in the water balance as an input into the system.

6.3.3 Other

It is understood that water will be available for use if required from the existing Karuah Hard Rock Quarry, adjacent to the Project. This source has not been included in the water balance to enable an understanding of the predicted water deficit or surplus from the quarry over time, and hence enable the water balance to predict if additional water will be required from sources such as the adjacent quarry to meet operational demands, and/or the predicted frequency of discharges from the site.

6.4 Water Losses and Usage (Model Outputs)

6.4.1 Evaporation

Long term historical evaporation data was not available from the Tahlee BOM station. Evaporation data was therefore sourced from the nearest station to measure this data; Williamtown BOM Station (No. 061078). Average monthly evaporation rates have been used within the water balance model, so that the daily evaporation rate varies throughout the year depending on the month. The volume of the evaporation also varies based on the estimated surface area of the water storages (which is relative to the volume of water storages) on each day.




6.4.2 Water Usage

Approximately 20ML per year is estimated to be required to meet the water demands of the quarry. Water will be required for the following uses:

Haul road dust suppression;

In the crushing plant and wash plant;

Pug mill; and

Dust suppression on the product stockpiles.

The water demands associated with these uses, and comments on how they are incorporated into the water balance, are provided in Table 9.

Table 9 - Predicted Water Usage

Water Demand Predicted Annual Usage (ML)

Estimated Daily Usage (ML)

Comments

Haul road dust suppression

5 0.0137 Haul road dust suppression is predicted to be approximately 5ML/year, however it only occurs in the water balance on days with less than 5mm of rain. Where more than 5mm rain is received, it is assumed dust suppression is not required on the haul roads.

Crushing plant 0.9

0.0025 A citrus based foaming dust control agent is to be used in the crushing plant, and hence minimal water usage will be required for dust suppression purposes in the plant. A small amount of water usage has been assumed in the water balance for dust suppression at 2.5kL/day.

Pug mill 1.84

0.005 Water usage based on an estimated product throughput in the pug mill of 100,000 tpa, and a water requirement of 20L/t of product. 8% of this water recycled, 92% going out with the product.

Wash Plant 0.55 0.0015 Assumes 15% of product to go through wash plant. At this rate, wash plant predicted to run 3 times /day using approximately 10,000L per wash, totally 30 kL. 95% of this water recycled, and 5% of water goes out with product = 1500L/day.

Product stockpile sprays

13.87

0.038 Assumes dust suppression applied to 2 stockpiles (fine aggregates only), at 8L/s for 2hrs per day, 4 months of the year. For the purposes of the water balance, this usage has been averaged over 12 months.

TOTAL 22.17 0.06

The estimated water usage for operation of the quarry has been developed based on tonnes of production and averaged over 365 days. However, the quarry will not operate on Sundays and public holidays, and as such will only operate for 265 days per year. As these non-operational days are distributed regularly throughout the year, the assumption of averaging water usage throughout the year is considered to adequately represent operation with regard to the water balance.




The water demands detailed in Table 9 are sourced from on-site water storages (sediment basins); unless storages are below the sediment zone in which case the water balance indicates a water shortage. When this occurs water will need to be sourced from off site. Further discussion on this is provided in the Water Balance Results, Section 6.6.

6.4.3 Site Discharges

The water balance assumes that discharges occur when the volume of water exceeds the onsite storage capacity. This assumes that a LDP will be obtained for the site, allowing discharges to occur.

It is also assumed that controlled releases from site are undertaken from the main water storage Dam 1 located in the crushing plant area. These releases are required to maintain the sediment basins in accordance with Blue Book requirements, which require sediment dams to be pumped out once the remaining storage falls below the required settling zone. Water quality in the sediment dams is to be monitored prior to release to ensure it is of an acceptable water quality for discharge. The total annual discharge has been estimated for two scenarios during the quarry’s operations, and these are presented in Sections 6.6.1 and 6.6.2.

With regards to operation and maintenance of the Dams, Dam 2 will be preferentially dewatered to Dam 1. This is so as to limit the risk of uncontrolled discharge during wet weather from this dam, due to the sensitive receiving environment downstream of Dam 2. It is assumed that a second LDP will be required at Dam 2; however this will only be required as a wet weather discharge point.

6.5 Storages

The water balance model assumes that the dirty water dams (sediment basins) are maintained such that the settling zone of is available for water storage during a rainfall event. Two dams are proposed; Dam 1, to be located within the catchment of the crushing plant, and Dam 2, within the catchment of the product stockpiles and the office infrastructure area. These dams and their maintained available storage are shown in Table 10. The available storage is the total volume of the dams, minus the required settling zone volume. This assumes that the dams remain pumped down to a level that ensures the settling zone is always available to manage runoff from the next rainfall event. In the case of Dam 1 the additional storage volume is assumed to be maintained for operational purposes on site and pump down will only occur when the remaining capacity is less than the minimum required settling volume.

Table 10 - Water Storages (assumed within water balance model)

Dam Total Storage Capacity (ML)

Available storage (ML)

Dam 1 12.4 3.1

Dam 2 5.2 4.3

TOTAL 17.6 7.4

The in-pit sump within the quarry has conservatively not been accounted for in the water balance. However, in practice the in-pit sump would serve as an additional water storage area during large rainfall events, thus further reducing the likelihood of uncontrolled discharges from Dam 1. In the water balance it is assumed that runoff collected in the pit is pumped out into Dam 1 and released under controlled conditions. This is to allow for the sump to be maintained in a dry state so that it does not impede on operational activities.

All dams are shown on Figure 3.




6.6 Water Balance Results

Water balance results are presented for two separate stages of quarry activities at Karuah East. Firstly, the water balance model was run based on the expected disturbance footprint at Stage 2 of quarry operations (i.e. a quarry footprint of 7.7 hectares. This is approximately half the amount of disturbance compared to when the quarry is at full extraction). The second scenario models surface water when the quarry is at full extraction nearing the end of the life of the quarry (i.e. Stage 5) and hence at maximum disturbance. It is noted that the disturbance footprint for the infrastructure area remains the same for both scenarios.

The water balance results for the selected scenarios are presented in the following sections.

6.6.1 Scenario 1 – Stage 2

The annual total data results from the water balance for all the relevant inputs and outputs of the water balance model for the Stage 2 Scenario (quarry disturbance of 7.7 ha) are illustrated on Figure 4. This figure demonstrates that there is a large variation in the data results for some of the inputs/outputs. Trend lines have been produced which provide a better tool for interpreting the results. The r-squared values for the trend lines are shown in Table 11 to provide a description of the nature of the trends. The closer the r-squared value is to 1.0 the better the trend lines fit the data. These trends were used to predict water balance results for dry, median and wet years.

Using the trend lines shown in Figure 4 as a guide, the predicted water balance totals for dry, median and wet years has been estimated and is shown in Table 11.

Table 11 – Indicative Water Balance Results for Stage 2 Scenario (Annual Summaries)

Description

Dry (ML/year)

Median (ML/year)

Wet (ML/year)

Water Source (Inputs)

Rainfall Runoff (r² = 0.9467) 46 74 115

Water Losses and Usage (Outputs)

Evaporation (from dams) (r² = 0.5403)

7 8 9

Water Usage (dust suppression including crushing) (r² = 0.6597)

20 19 18

Discharged (wet weather) (r² = 0.4149)

1 7 20

Controlled Release (r² = 0.8526) 18 38 68

Balance (Input-Output)

Change in water storage on site (*) -2.5 -4.3 -0.5

Note (*) Change in water storage is calculated from other data, rather than being read from the trend line




Figure 4 – Water Balance Results for Stage 2 Scenario




Water Supply

The results of the water balance model demonstrate that:

Rainfall runoff captured in sediment basins on-site will provide for the majority of water demand.

Additional sources of water are not anticipated to be required for the median or wet year scenarios. During a dry year, the water balance indicates a deficit of approximately 2.5 ML over the year. However, it is noted that this is based on a controlled discharge of 18 ML and the conservative assumption that no water storage is available in the quarry extraction area. However, at times throughout the year depending on the sequence of quarrying activities there would be opportunities to store water in the in pit sump, reducing the volume of controlled discharge required and hence reducing the water deficit on site.

Discharges from Site

The overall average of all rainfall years assessed in the water balance for the Stage 2 Scenario shows that on average there will be 3 days of uncontrolled discharges per year discharging an estimated total of 7 ML of sediment laden water. However, these discharge events occurred when the dam design criteria (i.e. rain of 90.6 mm in 5 days) was exceeded. In addition to this estimate, there will be approximately 19 days of controlled release per year, where 38 ML in total will be released under controlled conditions, within 5 days of a rainfall event and when suitable water quality in achieved.

This is consistent with the Blue Book, which states that dams are designed to spill. However it is noted that the Blue Book estimates an overflow frequency of 1 to 2 overflow events per year for dams designed to the 95th percentile criteria. The predicted average of 3 per year is slightly above this; however, as discussed above the actual discharge frequency is expected to be less given that there will be some capacity for water storage in the in-pit sump during large rainfall events.

As expected in dry years the likelihood of discharge decreases, and in wet years the likelihood increases. Interpretation of the results suggests the following likely discharges (and range of discharges) for the dry, median and wet years (shown in Table 12).

Table 12 - Predicted Discharges from Site for Stage 2 Scenario

Description Rainfall Year

Dry Median Wet

Number of Controlled

Discharge Days per Year

Total Number of Days Per Year (r2 = 0.4647)

0.5 Days

3 Days

7 Days

Total Volume Uncontrolled Discharge (per year)

1 ML 7 ML 20 ML

Total Volume Controlled Released (per year)

18 ML 38 ML 68 ML

Total Discharged 19 ML 45 ML 88 ML

Selected Representative Years

Figures 5, 6 and 7 show a summary of the water balance results for the specific historical rainfall years of:

1901 – 817.3 mm of rainfall and is therefore consider representative of what may occur in a dry year;

1968 – 1154.3 mm of rainfall and is therefore consider representative of what may occur in a median year; and




1990 – 1636.8 mm of rainfall and is therefore consider representative of what may occur in a wet year.

It is important to note that the results for these specific historical years do not match the statistical averages for the dry, median and wet years shown in Table 11. This is due to the scatter in results owing to many factors (such as initial dam storage and rainfall distribution) and showing they are not simply a direct relationship to how much rain fell in a year.

Figure 5 – Water Balance Results for Stage 2 Scenario - Historical ‘Dry Rainfall Year of 1901

Figure 6 – Water Balance Results for Stage 2 Scenario - Historical ‘Median’ Rainfall Year of 1968




Figure 7 – Water Balance Results for Stage 2 Scenario - Historical ‘Wet’ Rainfall Year of 1990

6.6.2 Scenario 2 – Stage 5 Full Extraction

Figure 8 shows the annual total data results from the water balance for all the relevant inputs and outputs of the water balance model for the Stage 5 Scenario.




.

Figure 8 – Water Balance Results for Stage 5 Scenario (Full Extraction)




Figure 8 demonstrates that there is a large variation in the data results for some of the inputs/outputs. Trend lines have been produced which provide a better tool for interpreting the results, and predicting water balance results for dry, median and wet years.

Using the trend lines shown in Figure 8 as a guide, the predicted water balance totals for dry, median and wet years has been estimated and is shown in Table 13.

Table 13 – Indicative Water Balance Results for the Stage 5 Scenario (Annual Summaries)

Description

Dry (ML/year)

Median (ML/year)

Wet (ML/year)

Water Source (Inputs)

Rainfall Runoff (r2 = 0.955) 69 110 170

Water Losses and Usage (Outputs)

Evaporation (from dams) (r2 = 0.5243)

8 9 10

Water Usage (dust suppression including crushing) (r2 = 0.6611)

20 19 18

Wet weather discharge (r2 = 0.6021)

2 14 39

Controlled Release Water (r2 = 0.7993)

39 66 101

Balance (Input-Output)

Change in water storage on site (*) -1.0 -3.9 -0.5

Note (*) Change in water storage is calculated from other data, rather than being read from the trend line

The primary change in the water balance results for Stage 5 compared to Stage 2 is the increase in rainfall runoff, which is a result of the increase in the disturbance area associated with the quarry, and hence an increase in runoff to be managed in the surface water management system.

Water Supply

The results of the water balance model predict that:

Rainfall runoff captured in sediment basins on-site will provide for the water demand; and

Additional sources of water supply are not anticipated to be required for the dry, median or wet year scenarios.

Hence, under normal operating conditions as per the assumptions used in the water balance, a water deficit is not predicted at Karuah East when the quarry is at maximum disturbance.

Discharges from Site

The overall average of all rainfall years assessed in the water balance for the Stage 5 Scenario shows that on average there will be 6 days of uncontrolled discharges per year discharging an estimated 14 ML in total of sediment laden water. However, these discharge events occurred when the dam design criteria (i.e. rain of 90.6 mm in 5 days) was exceeded. In addition to this estimate, it is predicted there will be approximately 33 days of controlled release per year, where a total of 66 ML will be released under controlled conditions, within 5 days of a rainfall event and when suitable water quality in achieved.

The total number of discharges is slightly higher than predicted in the Blue Book, which states that for dams designed to the 95th percentile criteria, there is likely to be from 1 to 2 overflow events per year.

The events where discharge occurred, but the design criteria was not exceeded, were all as result of a combination of the following factors:

A high rainfall period had proceeded the day of discharge so that dams were at full capacity before the event occurred; and/or




A substantial rainfall event in a short period of 1 to 2 days.

As expected in dry years the likelihood of discharge decreases, and in wet years the likelihood increases. Interpretation of the results suggests the following likely discharges (and range of discharges) for the dry, median and wet years (shown in Table 14).

Table 14 – Representative Discharges from Site for Stage 5 Scenario – dry, median and wet years

Description Dry Median Wet

Number of Controlled

Discharge Days per Year

Total Number of Days Per Year (r2 = 0.6423)

2 Days

6 Days

13 Days

Total Volume Uncontrolled Discharge (per year)

2 ML

14 ML

39 ML

Total Volume Released (per year) 39 ML 66 ML 101 ML

Total Discharged 41 ML 80 ML 140 ML

As illustrated in the table above, the volume of water discharged offsite increases as the annual rainfall increases.

Selected Representative Years

Figures 9, 10 and 11 show a summary of the water balance results for the specific historical rainfall years of 1901 (dry), 1968 (median) and 1990 (wet), as described above.

As discussed above for the Stage 2 scenario, it is important to note that the results for these specific historical years do not match the statistical averages for the dry, median and wet years shown in Table 13. This is due to the scatter in results owing to many factors (such as initial dam storage and rainfall distribution) and showing they are not simply a direct relationship to how much rain fell in a year.

Figure 9 – Water Balance Results for Stage 5 Scenario - Historical ‘Dry’ Rainfall Year of 1901




Figure 10 – Water Balance Results for Year 5 Scenario - Historical ‘Median’ Rainfall Year of 1968

Figure 11 – Water Balance Results for Year 5 Scenario - Historical ‘Wet’ Rainfall Year of 1990

6.7 Sensitivity Analysis

A number of assumptions were required during the development of the water balance model. This was necessary due to uncertainty associated with the parameters used to develop the model. In setting up a water balance model, data from the current operations if available is generally used to calibrate the model in order to minimise the uncertainty associated with assumptions. However, as data was not available at




this stage of the proposed project a sensitivity analysis was performed on the model to test the impact of potential variability in the assumptions.

The sensitivity analysis entailed varying the values of the significant model inputs which were subject to assumptions and observing the variability in the model output as a result. The model outputs chosen as indicators of the model’s performance were ‘Make-up Water (days/year)’, ‘Controlled Release (ML/year)’ and ‘Uncontrolled Discharge (ML/year)’. These output variables indicate the model’s response to the need for additional water, to be trucked in, and the annual volume of uncontrolled discharge experienced during wet periods. An overview of the results is presented here with the results of the sensitivity analysis tabulated in Appendix 1.

The model displayed most sensitivity towards the runoff coefficients for the hardstand and infrastructure areas. The amount of water required for dust suppression and the additional dam storage capacity also affected the models outputs. The runoff coefficient affects the volume of rainfall that contributes to runoff, hence an increase in this value results in an increase in the amount of uncontrolled discharge from site. However, the model assumes a conservative initial loss with a relatively high continuing partial loss, therefore it is expected that the actual runoff will trend lower than the assumed values. Dust suppression represents the largest use of water on site and an increase in this volume was the most likely to result in a water deficit. Changing the dam storage capacity generally only has a small effect on the discharges from site.

In the case of ‘dust suppression’ inputs, should Project Approval be granted it is recommended that the model be updated with data based on measured water usage once the quarry is operational. Additionally, it is suggested that the runoff coefficients are calibrated to the observed discharges on site after the dams are constructed. Once calibrated the water balance should be updated with the appropriate values.

6.8 Conclusions

The overall results of the water balance indicate that the site will have adequate water supply through the rainfall runoff captured in sediment basins.

The site will implement management practices to flocculate and undertake controlled release of treated water off-site when dam levels are high and do not provide adequate settling volume. Through maintaining the settling volume the sediment dams have the capacity to contain most of the events where preceding rainfall is less than the 90.6 mm (in 5 days).The model indicates that discharges are likely to occur for 3 and 6 days in average rainfall years in Stages 2 and 5 respectively, and controlled releases are likely to occur from 19 to 33 days on average per year. However, the likelihood of uncontrolled releases occurring are considered to be conservative and likely to be less, as in practice the quarry in-pit sump would provide substantial additional temporary on-site storage during and following rainfall events.

Overall the water balance indicates that the site will be relatively well balanced, with an estimated 281 days in the 40170 day record modelled where water would be required to be trucked in for operational purposes.

6.9 Recommendations

It is recommended that:

The proposed dams are built to at least the specified sizes, and made larger where practical in consultation with NOW, in particular with regard to dam licencing requirements, to provide additional storage in order to further reduce the risk of uncontrolled discharge. Increasing the total storage will provide opportunity to detain and treat water prior to controlled release (see below);

That controlled discharge of treated (e.g. flocculated) water be undertaken when total site storage levels are above 10.2 ML, which would provide the capacity to contain more rainfall events and reduce wet weather discharges. This assumes that dams are built to the capacities presented in this report, i.e. Dam 1 – 12.4ML, and Dam 2 - 5.2ML. It is the controlled release of treated water during dry weather that will have the most significant impact on reducing the potential for discharge




of sediment laden water. Whilst the overall discharge volumes will not change significantly, discharge in a controlled manner allows adequate settlement of sediment to be achieved prior to release; and

All water usage is monitored across the site to enable an update of the water balance using actual metered water usage data after 12 months of operation. Water usage is one of the key model inputs of the water balance, and hence calibration of the model against actual usage is critical to ensure the water balance accurately reflects the operation of the quarry.


Surface Water Assessment Site Water Management Plan


7.0 SITE WATER MANAGEMENT PLAN

A Site Water Management Plan (SWMP) will be prepared following project approval in accordance with regulatory requirements and conditions of consent. The SWMP will be developed in accordance with the Blue Book (Volume 1 and Volume 2E), and will address the impacts and mitigation measures discussed in Section 6 of this Surface Water Assessment.

It is recommended that the SWMP incorporate the following:

On-site soil and water management principles and objectives, including the following:

Containment of dirty water runoff from the active quarry area by directing this water into in-pit sumps.

Directing sediment-laden runoff from disturbance areas and rehabilitated areas into designated sediment control dams.

Installing temporary erosion and sediment control devices as required (i.e. sediment fences, sand bag weirs) to minimise the discharge of sediment laden water from newly disturbed areas.

Diverting clean water runoff unaffected by the operations away from disturbed areas and off-site, where possible.

Maintaining sediment control structures to ensure that the designed capacities are maintained for optimum settling of sediments.

Implementing an effective revegetation and maintenance program for the site.

Identification of sources of sedimentation and erosion.

Soil Best Management Practices (BMPs) to be implemented on-site, including:

quarry planning considerations (such as minimising disturbance);

topsoil/subsoil handling and stockpiling procedures; and

topsoil/subsoil respreading procedures.

Water BMPs to be implemented on-site, including;

clean water diversions;

dirty water capture and treatment;

additional sediment protection measures to be employed during the life of the Project; and

maintenance of sediment control structures.

Drainage line rehabilitation.

Water monitoring procedures.

Documentation and reporting procedures.


Surface Water Assessment Surface Water Monitoring Program


8.0 SURFACE WATER MONITORING PROGRAM

8.1 Introduction

The proposed Surface Water Monitoring Program for Karuah East Hard Rock Quarry details a recommended program to monitor both the surface water quality upstream and downstream of the site, and the effectiveness of the Site Water Management Plan.

8.2 Baseline Data

The baseline water quality data available for the site is presented in Section 3.7. The amount of baseline data available for the receiving waters is fairly limited due to the ephemeral nature of drainage lines in the general area and the limited extent of existing monitoring results. Notwithstanding this, the results of surface water monitoring undertaken during quarrying operations at Karuah East will be compared against the baseline data collected as part of this Surface Water Assessment to assist in assessing whether any impacts are occurring on the surrounding surface water environment.

In addition, it is noted that the EAR’s for the Project discuss the requirement to undertake baseline ecological health condition assessment of Yalimbah Creek receiving water as part of a future monitoring strategy. This baseline ecological assessment will be undertaken prior to commencement of operations, and monitoring of Yalimbah Creek will continue as part of the annual ecological monitoring of offset areas.

8.3 Surface Water Monitoring Parameters and Impact Assessment Criteria

The recommended parameters to be measured at each monitoring location via collection of a grab sample are presented in Table 15. The recorded values for the parameters measured should be assessed as a minimum against the baseline water quality results presented in section 3.7, as well as the ANZECC trigger values presented in Table 15, and plotted to identify any trends over time. The OEH should be notified in the event of increasing levels of any parameter.

The range of analytes measured should be reviewed following the first 12 months of monitoring and a diagnostic set of analytes adopted for ongoing monitoring.

Table 15 - ANZECC Trigger Values

Parameter Unit ANZECC Guidelines1

pH (Field) -- 6.5 – 8.5

Conductivity (Field) uS/cm 125 – 2200

Conductivity (Lab) uS/cm 125 – 2200

Total Dissolved Solids mg/L -

Total Phosphorus mg/L 0.025

Ammonia mg/L 0.02

Nitrogen (Nitrate) mg/L 0.350

Total Hardness (as CaCO3)

mg/L --




Parameter Unit ANZECC Guidelines1

Oil & Grease mg/L --

Arsenic mg/L 0.024

Cadmium mg/L 0.0002

Calcium mg/L --

Chromium mg/L 0.001

Copper mg/L 0.0014

Lead mg/L 0.0034

Magnesium mg/L --

Manganese mg/L 1.9

Nickel mg/L 0.011

Potassium mg/L --

Sodium mg/L --

Vanadium Mg/L --

Zinc mg/L 0.0312 1 Key default trigger values presented in ANZECC 2000 for slightly disturbed upland rivers in NSW (refer to Section 4.3.3). Heavy metals based on hard water (120-179 mgCaCO3/L)

8.4 Monitoring Locations

The recommended surface water monitoring locations are as follows:

Dam 1;

Dam 2;

SW1 & SW 2 - Existing second order drainage line (within Lot 13 flowing along the eastern boundary of the Study Area); both upstream and downstream of the quarry.

SW 3 - Existing drainage line downstream of Dam 2;

SW 4 - Existing drainage line downstream of the quarry extraction area.

Table 16 identifies the monitoring point locations, the type of monitoring point, and the frequency of sampling. The location of these monitoring points is shown on Figure 3.




Table 16 - Proposed Surface Water Monitoring Locations

Location Type of Monitoring Point

Description of Location Frequency

Dam 1 Water Quality Proposed dam located in crushing plant area

Monthly, and within 24 hours of any discharge. Also prior to any controlled (i.e. planned) discharge.

Dam 2 Water Quality Proposed dam located in stockpile area

Monthly, and within 24 hours of any discharge. Also prior to any controlled (i.e. planned) discharge.

SW1 Water Quality Existing second order drainage line upstream of site

Monthly (if creek flowing)

SW2 Water Quality Existing second order drainage line downstream of site

Monthly (if creek flowing) and within 24 hours of any discharge.

SW3 Water Quality Downstream of Dam 2 Monthly (if creek flowing) and within 24 hours of any discharge.

SW4 Water Quality Downstream of quarry extraction area.

Monthly (if creek flowing)

Water management (erosion and sediment control) structures

Erosion and Sediment Control

All noted erosion and sediment control structures.

Monthly and after significant rainfall events

8.5 Reporting of Monitoring Data

It is recommended that Karuah East Quarry Pty Ltd collate surface water analysis data and maintain an up to date record of analysis both in hard copy (laboratory reports) and electronic (results) format. These results should be interpreted as they are received in order to ensure appropriate operational guidance on maintaining water quality within desired parameters.

The results of water quality analysis will need to be reported in the Annual Environmental Management Report (AEMR), and should be made available to the Community Consultative Committee (CCC) members on a regular basis, if a CCC is required by the Major Project Approval.

In the event that an exceedance in surface water quality criteria is identified, the exceedance will need to be reported to the relevant agencies in accordance with the requirements of the EPL.


Surface Water Assessment Conclusion


9.0 CONCLUSION

The drainage lines that will be affected by the proposed Karuah East quarry are very minor headwater drainage lines that are ephemeral in nature and only flow for short periods after heavy rainfall. There was no volumetric flow data for these streams and little baseline water quality information to help quantify the potential impacts. However it is anticipated that there will be minimal impact on flow regimes downstream of the Study Area due to the Project.

Available soil and water data for the Study Area suggests that TSS is likely to be the key water quality parameter requiring management throughout the life of the Project to ensure the water quality in downstream watercourses is not impacted. A number of surface water management and mitigation measures are recommended by this Surface Water Assessment to ensure that the potential risk of any adverse off-site surface water impacts is minimised. This includes directing dirty water runoff into suitably sized sediment basins, use of water from the sediment basins for operational activities and the use of chemical flocculants to help increase settlement times where required.

A water balance model was developed for the Project, and modelled two representative stages of the quarry life; Stage 2, which represents approximately half the proposed disturbance footprint of the quarry, and Stage 5, which represents the quarry at full extraction and disturbance footprint near the end of life of the quarry. The water balance indicates that the site would be relatively balanced, with sufficient water available for reuse in the majority of dry periods and some wet weather discharges following large rainfall events. However, calibration of the model using actual site data collected during the first 12 months of operation of the quarry is highly recommended to confirm assumptions in the water balance, particularly relating to water usage, to allow for a more reliable model to be developed.

Based on the estimated water usage associated with the operation of the quarry, the overall results of the water balance indicate that the site is likely to have adequate water supply through the rainfall runoff captured in sediment basins.

The model also indicates likely annual wet weather discharges of 3 and 6 days per year in Stages 2 and Stage 5 respectively, and controlled releases to occur for approximately 19 and 33 days in Stages 2 and Stage 5 respectively, assuming an average rainfall year. However, it is considered likely that the wet weather discharges will be less as in practice the quarry in-pit sump will provide additional storage (temporarily until pumped to Dam 1) following heavy rainfall events, and sediment basins will be managed to achieve controlled release (after flocculation) to ensure there is available capacity in these basins to store runoff prior to a rainfall event.

If the surface water management and mitigation measures identified and discussed within this Surface Water Assessment are implemented and maintained, it is anticipated that there would be minimal impact on surface water downstream of the Study Area as a result of the proposed Karuah East Hard Rock Quarry.


Surface Water Assessment References


10.0 REFERENCES

ADW Johnson Pty Limited (April 2009), Preliminary Environmental Assessment, Proposed Hard Rock Quarry.

ADW Johnson Pty Limited (October 2004), Environmental Impact Statement, Proposed Hard Rock Quarry Extension.

ANZECC (2000), Australian and New Zealand Guidelines for Fresh and Marine Water Quality.

Coffey Geotechnics (2011), Proposed Karuah East Hard Rock Quarry, Groundwater Impact Assessment.

Department of Environment and Climate Change (DECC) (2008), Managing Urban Stormwater: Soils and Construction – Volume 2E Mines and Quarries, (the Blue Book Volume 2E).

Department of Water and Energy (2008), Guidelines for Controlled Activities – Riparian Corridors and In-stream works.

Department of Water and Energy (May 2008), Farms Dam Assessment guide (Factsheets) – http://www.water.nsw.gov.au/Water-Licensing/Basic-water-rights/Harvesting-runoff/Harvesting-runoff/default.aspx (first visited 08/09/2010).

GSS Environmental (2011), Karuah East Proposed Hard Rock Quarry – Soil Survey and Land Resource Impact Assessment.

Hunter-Central Rivers Catchment Management Authority (July, 2006), Hunter-Central Rivers Catchment Action Plan.

Institution of Engineers Australia (1998), Australian Rainfall and Runoff

Landcom (2004), Managing Urban Stormwater: Soils and Construction – Volume 1, 4th Edition, (the Blue Book Volume 1).

NSW Government Water Quality and River Flow Objectives - Hunter-Central Rivers, http://www.environment.nsw.gov.au/ieo/Karuah/index.htm (first visited 08/09/2010)

NSW Water Resources Council (1993), NSW State Rivers and Estuaries Policy.

RPS Australia East Pty Ltd (2011), Ecological Assessment Report – Karuah East Quarry.

Sensitivity Analysis

AP

PE

ND

IX 1


Surface Water Assessment Appendix 1


Table 17 Sensitivity Analysis for Stage 2 - Historical Dry Year (1901)

Parameter tested for sensitivity Dry Year (1901)

Lower Bound Current value Upper Bound

Additional Dam Storage Capacity 6.0 8.0 10.0

Make-Up Water Required (days/year) 0.0 0.0 0.0

Controlled Release (ML/year) 24.0 24.0 22.0

Uncontrolled Discharge (ML/year) 0.0 0.0 0.0

Runoff Coefficient - Hardstand 0.5 0.7 0.9


Controlled Release(ML/year) 16.0 24.0 32.0


Runoff Coefficient - Infrastructure 0.3 0.5 0.7




Dust Suppression - Water Use 14.2 18.9 23.6




Crushing Plant - Water Use 0.68 0.90 1.13




Plug Mill - Water Use 1.38 1.84 2.30




Wash Plant - Water Use 0.41 0.55 0.69







Table 18 Sensitivity Analysis for Stage 2 - Historical Median Year (1968)

Parameter tested for sensitivity Median Year (1968)

































Table 19 Sensitivity Analysis for Stage 2 - Historical Wet Year (1990)

Parameter tested for sensitivity Wet Year (1990)

































Table 20 Sensitivity Analysis for Stage 5 - Historical Dry Year (1901)

Parameter tested for sensitivity Dry Year (1901)

































Table 21 Sensitivity Analysis for Stage 5 - Historical Median Year (1968)

Parameter tested for sensitivity Median Year (1968)

































Table 22 Sensitivity Analysis for Stage 5 - Historical Wet Year (1990)

Parameter tested for sensitivity Wet Year (1990)






























Documents

FINAL Surface Water Assessment