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Environmental Impact Assessment Report For
(Proposed Karimenu Water Scheme)
WATER AND SANITATION SERVICES IMPROVEMENT PROJECT
(WaSSIP)
February 2009
Environmental Impact Assessment Report for Karimenu Water Scheme 1
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Environmental Impact Assessment Report for Karimenu Water Scheme
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CHAPTER 1: INTRODUCTION CHAPTER 1: INTRODUCTION............................................................................2
1.1 GENERAL......................................................................................................5 1.2 PROJECT BACKGROUND ..........................................................................7 1.3 PROJECT JUSTIFICATION .........................................................................8 1.4. STUDY OBJECTIVES..................................................................................9 1.5 ASSESSMENT SCOPE AND TERMS OF REFERENCE ...........................9 1.6 METHODOLOGY .......................................................................................10 1.7 METHODOLOGY STAGES .......................................................................11
Pre-Assessment activities: .............................................................................11 EIA activities: ................................................................................................11 Post-Assessment activities:............................................................................11
CHAPTER 2: PROJECT DESCRIPTION ...........................................................12 2.1 GEOGRAPHICAL LOCATION..................................................................12 2.2 CURRENT STATUS....................................................................................12 2.3 MAIN FACILITY COMPONENT...............................................................13 2.4 IMPLEMENTATION SCHEDULE.............................................................13 2.5 PROJECT COST ..........................................................................................14
CHAPTER 3: BASELINE INFORMATION........................................................15 3.1 TOPOGRAPHY AND PHYSIOLOGY .......................................................15 3.2 DRAINAGE AND HYDROLOGY..............................................................15 3.3 BIODIVERSITY ..........................................................................................15
Vegetation and Animal species......................................................................15 3.4 CLIMATIC CONDITIONS..........................................................................15
Rainfall...........................................................................................................15 Temperatures..................................................................................................16 Humidity and Evaporation.............................................................................16
3.5 GEOLOGY AND SOILS .............................................................................16 3.6 WATER RESOURCES ................................................................................16
Surface Water.................................................................................................16 Ground Water.................................................................................................16
3.7 WATER QUALITY ASPECTS ...................................................................16 Sewage / and other effluents ..........................................................................16 Solid wastes ...................................................................................................17
3.8 SOCIAL SETTING ......................................................................................17 Population and Settlement Patterns ...............................................................17
CHAPTER 4: ENVIRONMENTAL POLICY AND LEGAL FRAMEWORK ...18 4.1 NATIONAL ENVIRONMENTAL ACTION PLAN...................................18 4.2 POLICY PAPER ON ENVIRONMENT AND SUSTAINABLE DEVELOPMENT.............................................................................................................................18 4.3 THE ENVIRONMENT MANAGEMENT AND COORDINATION ACT (EMCA).............................................................................................................................19 4.4 THE WATER ACT 2002. ............................................................................20
Section 18.......................................................................................................20 4.5 WATER RESOURCES MANAGEMENT RULES 2007............................21 4.6 PUBLIC HEALTH ACT. .............................................................................21
Under Section 126..........................................................................................22
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Section 136; ...................................................................................................22 4.8 THE PHYSICAL PLANNING ACT, CAP 286...........................................23 4.9 LAND PLANNING ACT (CAP 303). .........................................................23 4.9.1 AGRICULTURE ACT (CAP 318)............................................................24 4.9.2 THE LAND ACQUISITION ACT CAP 295. ...........................................24
CHAPTER 5: ENVIRONMENTAL IMPACT ASSESSMENT.........................25 5.1 ENVIRONMENTAL AND SOCIO ECONOMIC IMPACTS ....................25
5.2.1 Positive Effects .....................................................................................25 5.2.2 Negative Impacts ..................................................................................26
CHAPTER 6: ENVIRONMENTAL MGT & MONITORING PLAN 6.1 CONSTRUCTION PHASE: ENVIRONMENTAL MGT PLAN................29
CONSTRUCTION ENVIRONMENTAL MANAGEMENT PLAN............31 6.2 OPERATION PHASE: ENVIRONMENTAL MANAGEMENT PLAN ....37
EMP DURING OPERATION .......................................................................38 6.2 DECOMMISSIONING PHASE: ENVIRONMENTAL MANAGEMENT PLAN............................................................................................................................42
EMP DURING DECOMMISSIONING OF THE PLANT...........................43 6.4 MONITORING AND ENVIRONMENTAL AUDITING...........................45
CHAPTER 8: CONCLUSION AND RECOMMENDATION .............................47 PHOTOGRAPHS ..................................................................................................48 LIST OF REFERENCES.......................................................................................53
Environmental Impact Assessment Report for Karimenu Water Scheme
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ANNEXES
Annex I Water Test Analysis Report Annex II Project Map Location Annex III Public Participation document Annex IV Responses to World Bank Environment specialist Annex V Responses to NEMA comments LIST OF TABLES Table 1 Water Service provider under AWSB Table 2 Access to water by Districts under AWSB Table 3 Diagrammatic Representation of the project
Environmental Impact Assessment Report for Karimenu Water Scheme
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1.1 GENERAL
The Government of Kenya (GOK), through the Water Act (2002) aims at providing
harmonized and streamlined management of water resources, water supply and sewerage
services through institutional reform. With support of IDA the reforms have been
accelerated in Nairobi and the adjacent four districts of Kiambu East, Kiambu West, Thika
and Gatundu which resulted to strong governance and an institutional and service delivery
framework that has enabled fairly efficient and sustainable delivery of water and sewerage
services to the population. The GOK recognize the need to strengthen the gains achieved
through the reform initiatives by increasing investments in the water supply and sewerage
sector in order to remove the bottlenecks to achieving poverty reduction and economic
growth objectives as stipulated in Vision 2030.
Increasing access to sustainable and affordable water services is a priority of the
Government within the overall policy framework of the Economic Recovery Strategy for
Wealth and Employment Creation. In order to address the problems associated with access
and provision of water services, the Government has embarked on reforms in the water
sector under the framework of the Water Act 2002.
The Act aims at providing for a harmonized and streamlined management of water
resources and water supply. Athi water Services Board (AWSB) and the Ministry of Water
and Irrigation (MWI) are spearheading the implementation process.
These reforms were mainly occasioned by the inability of the existing arrangements for
provision of water services to deliver and maintain basic water supply infrastructure for the
growing population and the need to have structured coordination of the various actors
involved in the water sector.
The institutional framework set out in the Water Act 2002 aims at ensuring that policy
formulation, regulation and service delivery roles are clearly delineated, with each role
being carried out by a separate entity. The Ministry of Water and Irrigation (MWI) will no
longer be involved directly in management of water services. It will mainly undertake
policy formulation, sector strategy development, Research and training, sector
Environmental Impact Assessment Report for Karimenu Water Scheme
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coordination, planning and financing.
The Water Services Regulatory Board (WSRB) is responsible for the regulation of water
and sewerage services including development and maintenance of quality standards and
issuance of licenses for service provision. Water Services Boards (WSBs) have the legal
responsibility for provision of water and sewerage services within their prescribed areas of
jurisdiction under license from WSRB.
Their responsibilities include holding or leasing and developing water assets, contracting
Water Service Providers (WSPs) who shall be their main agents in provision of water
services, and preparing plans for improvement of services including expanding service
coverage and reviewing tariffs.
WSPs are the entities through which the WSBs will provide water and sewerage services
under appropriate agreements entered into between them with approval of the WSRB. The
WSPs may be community groups, NGOs, private companies including those set up by local
authorities for the specific purpose of operating water services.
Water Services Board formed out of these reforms are Athi, Tana, Tana-Athi, Coast,
Northern, Lake Victoria North, Lake Victoria South and Rift Valley Water Services
Boards.
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TABLE 1: WATER SERVICE PROVIDERS UNDER AWSB
Water Company Name Address (P.O. Box)
Town
1 Kiambu Water & Sewerage Company Ltd 176 Kiambu 2 Gatundu South Water & Sanitation Company
Ltd 140 Gatundu
3 Karimenu Community Water & Sanitation Company Ltd
170 Gatukuyu
4 Gatanga Community Water Project 6133 Thika 5 Limuru Water & Sewerage Company Ltd 1286 Limuru 6 Kikuyu Water Company Limited 313 Kikuyu 7 Ruiru Juja Water & Sewerage Company Ltd 1165 -00232 Ruiru 8 Nairobi City Water & Sewerage Company Ltd 30656 - 00100 Nairobi 9 Kitisuru Water Company Ltd 30029 - 00100 Nairobi 10 Runda Water & Sewerage Company Ltd
505 00621 Nairobi
11 Githunguri Water and Sanitation Company Ltd 823 – 00216 Githunguri.
* (Source AWSB Rapid Result Study of 2005)*
1.2 PROJECT BACKGROUND
Karimenu water scheme is only a raw water distribution main constructed in the early
seventies.
During construction there was no habitation upstream of the intake works and therefore
there was no need of the full treatment. However, with time people have continued to
cultivate upstream of the said intake causing pollution through chemicals and eroded soils.
Population served by the project was then small as compared to the present. Population
increase resulted in demand exceeding supply. People sought alternatives sources
elsewhere including Nairobi Water Company mainline, to date, there are eighteen off-takes
serving about 3000 people from the Nairobi mainline.
With the proposed change of intake works an extra head of about 20m shall be created
within the system. The increased head will in return increase flow by about 3000m3 per
day to a total of 9000 cubic meters per day from the current 6000 cubic meters per day. In
addition to above and will construction of proposed full treatment works people currently
served by the 18 off-takes from Nairobi water mains will be connected to the new scheme.
This will allow Nairobi Water Company to supply additional consumers in Nairobi City.
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1.3 PROJECT JUSTIFICATION
Preliminary survey of Karimenu water project revealed that water project falls short of
satisfying target consumer population. With a design capacity of 960m3/d the population is
optimum but serving only 600 connections opposed to the original 2,300. This is a clear
indication of uneven water distribution and unaccountability as the supply is not metered.
Billing is done monthly on a flat rate basis and majority of the consumers particularly in
Karimenu location do not receive water hence they don’t pay.
Infrastructure development of the facility will therefore be necessary for the following
reasons
Revenue generation and collection
Extended water distribution network, accountability, accessibility and streamlined
monitoring capacity.
Improve the water treatment component therefore improving water quality
Clean up the intake to reduce the water purification
Provision of reliable affordable clean water to the consumers
Table 2: Access to water by districts under AWSB area in percentage
District Access to
water 2004
Access to
water
-2006
Access to
water
- 2012
5 year MDG
target increase
Thika 45 % 58% 71% 13%
Larger Kiambu 25% 34% 55% 20%
Nairobi 93% 91% 95% 3%
Average 54% 61% 74%
* (Source AWSB Rapid Result Study of 2005)
** (Source Economic survey of 2006)
From the table it is clear that the current supply of water in the district is not sufficient,
therefore initiating the proposed project will be a mile stone towards handling the problem
of water shortages in the district.
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1.4. STUDY OBJECTIVES
Main objectives of the assessment were to:
Verifying compliance to environmental requirements at both implementation and
operational stage
To identify past, present and potential future impacts on the environment of the
facility and evaluate their magnitude.
Propose appropriate mitigation measures for any identified adverse impacts, and
establish an environmental management plan for the project
Provide information that assures the public and government agencies that the
project is meeting statutory responsibilities in protecting the environment.
1.5 ASSESSMENT SCOPE AND TERMS OF REFERENCE
This report is prepared to meet the requirements of:
The Environment Management and Coordination Act 1999,
Water Act 2002
Water Resources management Rules 2007
Environmental (Impact Assessment and Audit) Regulations, 2003; and
The description of the project
A study of the relevant environmental law and regulatory frameworks on health and
safety, sustainable use of natural resources and acceptable environmental standards
A verification of the level of compliance by the project with the conditions of
environmental regulations and laws
A review of existing project documentation related to all infrastructural facilities
and designs;
An examination of the monitoring programs, parameters, and procedures in line
with control and corrective actions in case of emergencies;
An examination of records of incidences and accidents and the likelihood of future
occurrences of the incidences and accidents.
Preparation of a list of health and environmental concerns of past and on-going
activities.
An examination of the various materials, including non-manufactured goods, final
products, by-products and wastes
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A description of potentially affected environment component both ecological and
socio-economic matters
An identification of all environmental and occupational health and safety concerns
associated with the project
Detailed recommendations for corrective activities, cost, time and mechanism for
implementation.
Identify and establish baseline data (benchmarks) for various environmental and
human aspects relating to the project
1.6 METHODOLOGY
The methodology used complies with section 35 of the Environmental impact assessment
and audit regulations 2003, which states that: an environmental Impact Assessment and
audit shall be carried out through various ways; it is designed to be participatory in order to
capture the views of the proponent and the beneficiaries (both direct and indirect) of the
project. Both reactive and non-reactive research methods were employed in utilizing
various research tools in gathering information.
The following tools were used:
Direct field observation.
Literature review
Checklists.
Questioner’s administration to key informant
Interviews
Photographs.
Area of focus includes: Natural Environment, Human Environment, Physical Environment,
Sustainability, Environmental Monitoring and Protection. Major focus was on
Environmental Conservation, Water Supply, Social Welfare and Human Health and Safety
among others. Personal observations were necessary in order to identify environmental
aspects of the potential impact of the project.
Benchmarks for monitoring environmental aspects were identified. Finally face to face
interviewing of both direct and indirect beneficiaries was done to air out views and feelings
on the project. The tools employed were open-ended questions based on semi-structured
checklist. These were administered to various stakeholders and potential beneficiaries
(chiefly key informers) and individuals likely to be affected by the project.
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1.7 METHODOLOGY STAGES
Pre-Assessment activities:
i. Gathering of background information about the facility
ii. Advance visit to the site
iii. Review of the legal framework
iv. Definition of the objectives and scope of the assessment
v. Preparation of audit questionnaires
EIA activities:
i. An understanding of the management systems through meetings and interviews.
ii. An assessment of strengths and weaknesses inherent risks and internal controls.
iii. Gathering of impact evidence, assessment, documentation, verification, site inspection.
iv. Evaluation of impact evidence, compliance, exceptions, environmental program status
Post-Assessment activities:
i. Preparation of draft report to document findings and prepare recommendations.
ii. Review of the draft report with the client.
iii. Preparation of action plans, proposed actions, responsibilities for corrective action and
timelines.
In addition to documentation of the anticipated impacts and appropriate mitigation
measures, reporting was done by the terms of reference guided by NEMA. The project
report is structured as follows;
Executive summary
Introduction
Project description
Baseline information
Policy, Legal and institutional framework
Environmental impact assessment
Environmental Management plan
Conclusion and recommendation
List of references
Appendices
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CHAPTER 2: PROJECT DESCRIPTION
2.1 GEOGRAPHICAL LOCATION
Karimenu Water Supply is located in Gatundu North district, Gatukuyu division, Karimenu
location Gakoe sub-location
2.2 CURRENT STATUS
Currently, there is no treatment going on at the site as it is a new development where a weir
is being constructed to abstract water upstream in the Aberdare forest. The waters are to be
conveyed to the treatment plant that is designed to be at the peripheral of the forest in the
KFS land.
The current works were constructed in the early seventies and their capacity doubled in
2007 through intervention of AWSB. The scheme comprise of twin 250 cubic meters per
day of raw water.
During construction there was no habitation upstream of the intake works and therefore
there was no need of the full treatment. However, with time people have continued to
cultivate upstream of the said intake causing pollution through chemicals and eroded soils.
Secondly, the population served by the project was then small as compared to the present.
Population increase resulted in demand exceeding supply. People sought alternatives
sources elsewhere including Nairobi Water Company mainline.
To date, there are eighteen off-takes serving about 3000 people from the Nairobi mainline.
With the proposed change of intake works an extra head of about 20m shall be created
within the system. The increased head will in return increase flow by about 3000m3 per
day to a total of 9000 cubic meters per day from the current 6000 cubic meters per day. In
addition to above and will construction of proposed full treatment works people currently
served by the 18 off-takes from Nairobi water mains will be connected to the new scheme.
This will allow Nairobi Water Company to supply additional consumers in Nairobi City.
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2.3 MAIN FACILITY COMPONENT
The Key investments are for construction of source works, raw water main and 9000 cubic
meters per day treatment plant including;
The construction of the intake weir and the intake chamber along Karimenu River
Construction of 3 km of 300 mm diameter twin raw water gravity main
Construction of aerial crossings
Construction of 2 flocculation tanks
Construction of 4 units of sedimentation basins
Construction of 4 filter units
Construction of Chemical Building
Construction of Utility Building
Construction of 40 cubic meters steel elevated pressed steel backwash tank
Construction of backwash pump house and installation of backwash pumping units
Construction of 150 cubic meters masonry clear water tank
Construction of 1 No staff house
Construction of 500 meters all weather access road
Miscellaneous works including Fencing of treatment site
2.4 IMPLEMENTATION SCHEDULE
The works shall be done in two phases
Phase 1: Immediate measure
Completion of the water treatment works (Flocculants, sand filters, chemicals
dosing units, back washing)
Rehabilitation of existing works
Metering of all the distribution networks
Electricity connections
Construction and equipping of water supply laboratories
Phase II: Mid-term measures
Construction of the distribution system
Rehabilitation of existing distribution systems, storage facilities and replacement of
fittings
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Completion of staff housing
Support utility (Power generators, a pump house)
2.5 PROJECT COST
The project cost is estimated at Ksh 127,895,824
Environmental Impact Assessment Report for Karimenu Water Scheme
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CHAPTER 3: BASELINE INFORMATION
3.1 TOPOGRAPHY AND PHYSIOLOGY
Project area is characterized by steep slope and deep valleys. Physiographic of the region is
influenced by Aberdare ranges with topography varying from steep in the western region
and undulating landforms volcanic ranges in the Northern.
3.2 DRAINAGE AND HYDROLOGY
The project area is well drained both horizontally because of the horizontal valleys, vertical
slopes and loamy red volcanic soils which are porous and allow for all infiltration, the
ranges are covered by tea zones. Due to this, cases of flooding are not likely to happen.
Clearing of vegetation on the steep slopes is strictly discouraged as flush surface runoff is
likely to dominate the region. The catchments are constituted by lower Aberdare ranges
feeding to the numerous rivers and streams around.
3.3 BIODIVERSITY
Vegetation and Animal species
Agricultural land is the most important resource in the district. Most of the area lies in the
Agro-Eco-zone III and IV. Agriculture is the main economic activity in this area with tea,
coffee, cabbages and dairy farming being the main activities.
3.4 CLIMATIC CONDITIONS
Rainfall
The region is characteristic by equatorial climatic conditions and rainfall is highly
influenced by altitude and comes in two seasons. Long rains between March to May and
short rains between October and December. The annual mean rainfall varies from 1070mm
to 1750mm per annum.
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Temperatures
Temperature is also influenced by altitude due to the Aberdare ranges. Mean annual
temperature varies from low in higher regions to high in lower region between 17 and 25
degrees Celsius.
Humidity and Evaporation
Main wind direction is easterly and evaporation ranging from 100 to 150mm per month
while the humidity varies between 50% and 90%.
3.5 GEOLOGY AND SOILS
The geology of the area is part of the eastern border zone of the Rift Valley, filled with
kainozonic volcanic and sediments underlying the upper Athi generating good aquifers.
Soils on the other hand develop from weathering activities of the volcanic rocks and are
highly fertile with high levels of perforation.
3.6 WATER RESOURCES
Surface Water
Thika district is generally endowed with numerous springs, streams that constitute one
major Karimenu River that is serves the project area. The river provides the main source of
water to the residents of Karimenu who use the water either directly or through water
schemes such as Karimenu Water Scheme. But due to costs of harnessing water resources
most of the resource is under utilized.
Ground Water
Other sources of water in the region are numerous boreholes in the area with an average
yield of 7m3/hr and pumps set at an average depth of 200 to 300 m deep.
3.7 WATER QUALITY ASPECTS
Water quality monitoring is not done regularly but water is coloured brown and turbid
during the wet seasons. During the time of assessment the water was partly clear.
Sewage / and other effluents
Majority of the people have pit latrines with few having VIP latrine. A few private homes,
institutions and hospitals have septic tanks, but this does not rule out the possibility of
Environmental Impact Assessment Report for Karimenu Water Scheme
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contamination. Most alarming wastes are from cattle dips, spraying of pesticides, use of
chemical fertilizers and liquid wastes from agro- processing industries such as coffee, tea
and dairy plants.
Solid wastes
Wastes generated at various levels of the community are generally disposed off into the
natural environment. Most wastes generated include:
• Bio mass from crops and animal wastes
• Agrochemical wrappers, containers, polythene, plastics
• Urban wastes from shopping centers (Gakoe market )
3.8 SOCIAL SETTING
Population and Settlement Patterns
Settlement patterns are influenced by rural - Urban migration, good infrastructure and
proximity to Nairobi. Majority of the population reside around Gakoe shopping center
which is the main market near the project area. The project area is densely populated and
land is subdivided into uneconomic sizes.
Environmental Impact Assessment Report for Karimenu Water Scheme
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CHAPTER 4: ENVIRONMENTAL POLICY AND LEGAL
FRAMEWORK
This study was conducted within an environmental and policy framework as outlined
below and in particular, the Environmental Management and Coordination Act, 1999 which
has explicit provision for Environmental Impact Assessment (EIA) for projects likely to
have adverse environmental impacts.
The law governing environmental protection and conservation in Kenya are derived from
the constitutional statutes and the ratified international conventions. These laws regulate
the establishment and operation of development projects such as water treatment plants,
boreholes , water abstraction, roads, bridge and associated activities, which may impact
negatively on the environment, human health and socio – economic well being of the
people who interact with such projects. Today, NEMA coordinates all environmental
activities on behalf of the government of Kenya.
4.1 NATIONAL ENVIRONMENTAL ACTION PLAN
The Kenya National Environment Action Plan (NEAP), 1994 advocates for the integration
of environmental concerns into development projects by requiring that new projects
undergo the Environmental Impact Assessment before implementation.
4.2 POLICY PAPER ON ENVIRONMENT AND SUSTAINABLE
DEVELOPMENT.
The objectives of the Policy Paper on Environment and Sustainable Development (1993)
are to ensure that:
• All development programs and projects take environmental considerations into
account.
• An independent environmental impact assessment report is prepared for any
development project before implementation.
• Effluent treatment standards will conform to acceptable standard
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4.3 THE ENVIRONMENT MANAGEMENT AND COORDINATION ACT
(EMCA).
The Environmental Management and Coordination Act, 1999, came into force on 14th
January 2000. Its overall objective is to provide for the establishment of an appropriate
legal and institutional framework for the management of the environment. The act provides
a coordination mechanism for various Sectoral laws dealing with elements of the
environment.
Part II of Environment Management and Coordination Act 1999 states that every person in
Kenya is entitled to a clean and healthy environment and the duty to safeguard and enhance
the environment.
Part V section 42 states that “no person shall, without prior written approval of the
Director-General given after an Environmental Impact Assessment, in relation to a river
lake or wetland erect, reconstruct, place, alter, extend, remove or demolish any structure in,
or under the river, lake or wetland. The Act further states that no one shall excavate, drill,
tunnel or disturb the river lake or wetland.
Section 58 of the Act provides for an environmental impact assessment for all projects
likely to have adverse environmental impacts. The projects must undergo a mandatory EIA
as given in the second schedule of the Act. The operator must have self-audit through
which he/she can monitor effects of the operations on the environment and take initiatives
that are necessary for compliance with the provisions of the Act.
EMCA 1999 also has provision for Environmental Quality Standards, which includes
Water, Air, and Wastes, Pesticides Management, among others. The Act provides
legislation control over soil conservation and land management. Abstraction of water,
clearing of vegetation and any other land use activity on steep slopes, which are likely to
cause an environmental degradation are not recommended.
Environmental Impact Assessment and Audit Regulations, 2003, provides guidelines that
should be followed in carrying out an EIA which include qualification of experts and
aspects such as ecological, social, landscape, land use and effects of projects on water and
general drainage pattern.
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Under EMCA, 1999 a project proponent shall not implement a project likely to have
negative environmental impact, or for which an EIA is required, unless an EIA has been
concluded and approved in accordance with the law.
4.4 THE WATER ACT 2002.
The water Act 2002 is concerned with sustainable management of water resources. It
prohibits activities that may cause pollution of water sources for domestic, industrial,
agricultural or recreational use.
Section 25 of the Act requires a permit to be obtained for among other uses of water from a
water resource, discharge pollutant in a water resource. Section 75 and sub section 1 allows
a licensee for water supply to construct and maintain drains, sewers and other works for
foul water arising or flowing upon land for preventing water belonging to the licensee or
which he is authorized to take from being polluted. However, if the proposed works not
affect or is likely to affect any body of water in the catchments, the licensee shall obtain
consent from the water resources management Authority.
Section 76 states that no person shall discharge any trade effluent from any trade premise
into sewers of a licensee without the consent of the licensee upon application indicating the
nature and composition of the effluent, maximum quantity anticipated, flow rate of the
effluent and any other information deemed necessary. Underground water sources are
likely to be polluted by seepage of construction waste contaminants and drains-water from
the building. Construction work also uses a lot of water.
Section 18 of the Act provides for the National Monitoring and Information Systems on
water sources. Sub-section 3 allows the Water Resources Management Authority (WRMA)
to demand from any person or institution specified information, document, samples or
materials on water resources. Specific records are required to be kept by the site operator
and the information is furnished to the Authority. The Act allows the person with the
license to supply water and make regulations for the purpose of protecting it against
degradation of water sources.
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The Act makes it an offence to throw rubbish, dirt, refuse, effluent, trade waste or other
offensive matter into or near water sources in such a manner as to cause or likely to cause
pollution of the water resources.
4.5 WATER RESOURCES MANAGEMENT RULES 2007
According to the third schedule of the Water Resource Management Rules 2007, any water
activity that involves the under listed activities requires a water use permit.
Temporary abstraction of water for construction
Diversion of water from a water course
Abstraction from surface water
Diversion of a water course
Abstraction from ground water, either by borehole or a shallow well
Ground water recharge augmentation
Water storage in dams and pans
Effluent discharge being the disposal of wastes into a water resource
Swamp marsh or wetland drainage
In stream works
Mixing of water from different water resources
Hydro power generation
4.6 PUBLIC HEALTH ACT.
The Public Health Act (Cap 242) the main purpose of this Act is to secure and maintain
public health. Some of its provisions relevant to this project include prohibition of nuisance
activities such as spillage, discharge of untreated effluents or noise or other condition
deemed to be injurious or dangerous to human health.
According to Part IX Section 115 no person will be allowed to cause nuisance or condition
liable to be injurious or dangerous to human health .Section 116 requires local Authorities
to take all lawful, necessary and reasonably practicable measures to maintain their
jurisdiction clean and sanitary to prevent occurrence of nuisance on conditional liable for
injurious or dangerous to human health.
Environmental Impact Assessment Report for Karimenu Water Scheme
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The Act further states that nuisance conditions are defined according to the opinion of
Medical Officer of Health. Any noxious matter or waste water flowing or discharged from
any premises or project into a public street or into the gutter or site channel or water course,
irrigation channel not approved for discharge is also deemed as a nuisance.
Part XI Section 129 of the Act states that it is the duty of every local authority to take all
lawful, necessary and reasonably practicable measures for preventing any pollution
dangerous to health of any supply of water which the public within its districts has a right
to use for drinking or domestic purposes. It’s also charged with purification of water so
polluted.
Part XII Section 136 states that all collections of water, sewage, rubbish refuse and other
fluids which permits or facilitate the breeding or multiplication of animals or vegetable
parasite of men or domestic animals or insects or other agents which are known to carry
parasite shall be deemed nuisance and are liable to be dealt with as provided for in the Act.
Under Section 126 the Public Health Act gives the rules on drainage and latrines in
buildings. Under this section the local authority is the enforcer of such regulations. The
section refers to the local authority enforcing drainage of un-drained buildings, sinks and
drains to be provided in buildings and the examination of the drainage. It also prohibits
injurious substances being passed into sewers. Generally the section covers wastes disposal
in buildings and the role the local authority plays in wastes disposal management.
Under section 11 B of the Act provides rules that wastes pipes, sewer, drains or refuse pits
should be constructed in a state that would not be injurious or offensive to health. Any
noxious matter or wastewater flowing or discharge from any premises into a public street
or into the gutter or side channel be avoided. Other nuisances are accumulation of materials
or refuse which in the opinion of the medical officer of health is likely to harbor rats or
other vermin.
Section 136; states that all collectors of water, sewage, rubbish and others fluids which
permit or facilitate the breeding or multiplication of pests shall be deemed a nuisance and
are liable to be dealt with in the manner provided by the Act.
Environmental Impact Assessment Report for Karimenu Water Scheme
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4.8 THE PHYSICAL PLANNING ACT, CAP 286
The local authorities are empowered under section 29 to receive and maintain all land
planned for open spaces, parks, urban forests and green belts. t provides for the preparation
of a physical development plan for the purpose of improving the land and providing for the
proper physical development of such land, and securing suitable provision for
transportation, public purposes, utilities and services, commercial, industrial, residential
and recreational areas, including parks, open spaces and reserves and also the making of
suitable provision for the use of land for building or any other purposes.
The Physical planning act provides for the control of development and use of land in
particular areas, especially where a project may involve sub divisions or amalgamations of
land parcels or located in an area otherwise reserved for other use.
The objective of this Act is to promote harmony, convenience, comfort and beauty in land
use. Section 29 of the Act empowers local authorities to control all development activities
so as to ensure conformity to approved planning standards.
Section 30 states that any person who carry out development without permission will be
required to restore the land to its original conditions.
The Act also provides an environmental impact assessment for a project which is likely to
have injurious impact on the environment. Such an EIA should be approved by the
National Environment Management Authority (NEMA).
4.9 LAND PLANNING ACT (CAP 303).
This Act is the overall planning law for land for both agricultural and constructed
environments.
Under this Act, all developments or changes to land use must be approved by a planning
authority.
Section 9 of the subsidiary legislation (the development and use of land legislation 1961)
stipulates that before any plans are submitted to the Minister for approval steps should be
taken as may be necessary to acquaint the owners of any land affected such plans
particulars of comments and objects made by land owners should also be submitted. This is
meant to reduce conflicts with other interests such as residential and commercial land uses.
The Act ensures that all development plans within local authorities to be submitted to the
Ministry for approval, this is intended to reduce potential conflicts between the interests of
Environmental Impact Assessment Report for Karimenu Water Scheme
24
the authorities and those of landowners in respect of settlement, social and economic
activities.
The project area covers land legally granted under the Registrar of Tittles Act (Cap281).
4.9.1 AGRICULTURE ACT (CAP 318).
The Agriculture Act requires a person carrying out a land use activity that may lead to soil
land
degradation to take such measures to conserve the soil. Such activities may be abstraction
of water to a treatment plant, cultivation road construction, building and human settlement
Conservation measures must be implemented. It also restricts
4.9.2 THE LAND ACQUISITION ACT CAP 295.
This Act empowers the government and the local authority to acquire private landing in
accordance with section 117 and 118 of the constitution of Kenya for development that are
at the interest of the public. Acquired land is compensated at a market rate plus 15%
disturbance allowance. This Act has been very useful especially where land needs to be
acquired for public use. Similarly, the Government has often found it more convenient to
acquire land for urban development, which in turn gives it a greater influence in terms of
planning, and development control.
Environmental Impact Assessment Report for Karimenu Water Scheme
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CHAPTER 5: ENVIRONMENTAL IMPACT ASSESSMENT
Reliable water availability is considered to be critical to economic growth and poverty
reduction especially in agricultural zones that support urban and industrial activities
through provision of raw materials and food supply. With increasing pressure on land for
agriculture and settlement, water resources come under serious threat of degradation. Use
of chemical fertilizers and pesticides near drinking water sources exposes consumers to the
risk of water borne diseases, water pollution and sometimes conflict over use of resources.
Socio – economic needs of a particular community entirely require water, over abstraction
from sources, infrastructure maintenance, management of related wastewater and
ecological balance and sustenance is among the problems associated with public water
supplies.
From the foregoing, public water supplies such as Karimenu Project have far reaching
social and economic implications that need to be addressed throughout the project cycle.
The effects are mainly positive calling for enhancement and the negative ones calling for
mitigation
5.1 ENVIRONMENTAL AND SOCIO ECONOMIC IMPACTS
Environmental and socio economic impacts associated with the development of the
Karimenu Water Scheme are outlined below.
5.2.1 Positive Effects
Improved Water Quality and accessibility to clean water
Improved water quality will in turn reduce exposure to water borne diseases to the
consumers. General hygiene in the served area will improve through use of acceptable
water quality.
Majority of the population around Gakoe Township and entire Thika will have access to
clean water. Extension of the distribution networks will make more people access clean
water as compared to the number that is currently accessing. Adequate supply of water
from Karimenu Water Scheme will make it possible to disconnect them from the main lines
of Sasumua hence help release more water to Nairobi.
Improved living standards in Karimenu area
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Access to water will in the long term result in improved income levels and health of the
people, this consequently leads to poverty reduction. Reduced distances traveled and time
used to collect water is then put to economic activities.
Reduced Exposure to Health Risks
Improved water quality for domestic consumption reduces the risk to the health of the
consumers and dependants of water resources that could translate into financial saving
through less related expenditures
Improved Food Security and Nutrition
It will result from saving on health and incomes an diversification of farming activities of
high yield using irrigation, expansion of farming can bring back abandoned farm in
farming.
Stimulation of the Local Economy
Construction phase will stimulate local economy through procurement of construction
material and provision of labour by the locals. This will lead into increased capital flow and
demand for goods and services will increase. Water availability will also stimulate growth
of economic activities at local level
Sustainability of Karimenu Water and Sewerage Company
Increased revenue collection will help the company to be sustainable in terms of meeting
their own operational cost which are currently being met by Ministry of Water and
Irrigation
Enhanced Gender and Participation in Development
Female form a high percentage of the areas population but are in adequately participating
in development activities due burden of fetching water. Increased availability of water will
relieve them and thereby give them an opportunity to engage in development activities
5.2.2 Negative Impacts
Impacts on biodiversity
Destruction of vegetation around the intake and distribution areas
Interaction with wild animals within Aberdare forest e.g. elephants
Destruction of habitat
Water pollution
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Impacts on water resources
Possibility of over abstraction of water from river Karimenu River
Reduced flow of water in river Karimenu with effects of water shortage for users
and capacity of the river to assimilate and dilute wastes downstream
Supply of water to the consumer will consequently generate waste water. However
it is not easy to quantify how much of the waste water will reach the water bodies.
Due to large scale tea farming and heavy rainfall, possibility of non point pollution
is inevitable.
Impacts on Drainage and Hydrology
Abstraction of more water from the river Karimenu might reduce flow level down
stream due to ineffective compensation
Specific consumption points will require discharge point for the waste water,
improper drainage will lead to pools and channels with stagnant water harboring
vector diseases.
Impacts on public health
Temporal interference with water quality and distribution during construction
impacts negatively into people’s health.
During construction, network improvement, metering and treatment enhancement
will disrupt the hygiene and availability of clean water and hence potential water
borne infection.
There is a likely hood that with increased water availability probability of water
borne diseases will increase.
Impact on soil
Possibility of erosion at burst pipes along the steep slopes during construction
Siltation of springs and rivers as well as pollution of water at the valley bottoms
Disruption of soil structure during construction of treatment plant
Impacts on water cost
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Added water cost will be received negatively by the consumers especially the poor,
this may lead them to go for cheap available water sources hence cases water borne
diseases might increase
Metering of water distribution may also be associated to an increase of cost of
living which has a negative impact especially on the poor. Meter rent and delay in
installation meters may lead to the consumers buying their own which is also an
added cost
Impacts on Community Based Organization
With the taking over water management by the WSP, community based groups that
initially provided the same may collapse
Local water vendors who had also ventured in the same business will loss market
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CHAPTER 6: ENVIRONMENTAL MANAGEMENT AND
MONITORING PLAN
Environmental Management Plan (EMP) has been developed to assist in prioritizing the
key findings of the EIA, and to suggest necessary mitigation actions. From the EMP, a
schedule for the operations implementation could also be drawn that takes into
consideration all issues that could develop into serious risks to environment, health and
safety at all times.
Environmental management plan is based on the ISO 14001 which states management
principles for environmental management. Finally, management reviews and continuous
improvement determines which of the activities require to be re-visited and at what
schedules.
On the basis of the policy guidelines and development of the EMP, among other actions
recommended to be undertaken by the management in the implementation of the latter are;
• Develop a training plan and schedule,
• Develop an in-house environmental audit protocol and schedule,
• Establish a suitable and comprehensive database in environmental issues
• Put in place an emergency preparedness system
• Establish an EMP implementation schedule
• Establish an incident log book to manage environmental incidents
• Establish an environmental management committee to oversee and assist in the
implementation of the EMP.
The recommended mitigation measures and the targeted achievements have been tabulated
below. A timeframe has also been presented.
6.1 CONSTRUCTION PHASE: ENVIRONMENTAL MANAGEMENT PLAN
The following were key environmental concerns that need to be addressed during the
construction phase of the project. They include:
Environmental Impact Assessment Report for Karimenu Water Scheme
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• Effects on biodiversity
• Solid waste management issues
• Noise and vibrations from construction machineries
• Effluents from construction machineries to the quality of water
• Impacts of the construction activities on water quality
CONSTRUCTION ENVIRONMENTAL MANAGEMENT PLAN
Activity Source of
Impact
Impact Mitigation Measure Actors Cost
(KSH)
Clearing
vegetation
Bush clearing Loss of habitat Limit vegetation clearance to a minimum Contractor
Loss of fertile soil Pile the top soil where it can be reused
Contractor Stripping the
soil
Top Soil
removal
Loss of habitat Restrict disturbance to soil structure within
project site
Contractor
Soil Erosion Put measures for protection of soil erosion Contractor
Water contamination Control oil spillage by machinery Contractor
Earth Works Cuts and fills,
Graveling
Mud generation Installing necessary temporary and
permanent drainage works
Contractor
50,000
Hindrance to movement Provision of access routes to locals Contractor
Air Pollution
Ensure use of machine with low Carbon
emission
Ensure the use of dust suppressants
Conduct Regular Air Quality Test
Contractor
Mud Generation Provision of Drainages
Gravelling of Access Routes
Contractor
Water Contamination Control Oil Spillage Contractor
Construction Track
circulation
Accidents Ensure Proper Road Safety Measures Contractor
150,000
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Safety Gear for Workers & Site Visitors
Insurance Cover for Workers
Provision of First Aid & Medic’ Assistance
Impact on quality of
water and soil
Use of cleaner technologies / productions
Contractor
Impact on quality of
water and soil
Waste minimization, by recycling and reuse
of wastes generated
Contractor
Impact on quality of
water and soil
Green procurement where by all goods and
services procured should be eco friendly
Contractor
Solid waste
management
Soil and water
contamination
Careful disposal of non recycled wastes into
a landfill
Contractor
80,000
Impact on quality of air Maintaining machineries at manufacturers
specifications
Contractor
Impact on quality of air Site roads should be dampened every 4-6
hours or within reason to prevent a dust
nuisance and on hotter days, this frequency
should be increased.
Contractor
Gaseous
emissions
Excavations
Truck
movements
Impact on quality of air Minimize cleared areas to those that are Contractor
Environmental Impact Assessment Report for Karimenu Water Scheme
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needed to be used.
Cover or wet construction materials such as
marl to prevent a dust nuisance.
Impact on quality of air Where unavoidable, construction workers
working in dusty areas should be provided
and fitted with N95 respirators.
Contractor
Impact on quality of air Wetting of unpaved areas and the entire
work place
Contractor
Impact on quality of air Limit removal of vegetation and a
rehabilitation programme on site and
associated infrastructure following
construction
Contractor
50,000
Impact on health of the
workers & neighbors
Use equipment that have low noise
emissions as stated by the manufacturers.
Contractor
Impact on health of the
workers & neighbors
Use equipment that is properly fitted with
noise reduction devices such as mufflers.
Contractor
Impact on health of the
workers & neighbors
Workers should be provided by PPE Contractor
Noise pollution
and vibrations
Nuisance to the
ambient cool
Constructions should be limited between
50,000
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7.00 am to 6.00 pm
Impact on Ecology,
water and soil quality
Skips and bins should be strategically
placed within the campsite and construction
site, they should also be adequately
designed and covered to prevent access by
vermin and minimize odour.
Contractor Construction
activities
Impact on Ecology,
water and soil quality
The skips and bins at both the construction
campsite and construction site should be
emptied regularly to prevent overfilling.
Contractor
Solid Waste
Generation
Construction
activities
Impact on Ecology,
water and soil quality
Disposal of the contents of the skips and
bins should be done at an approved disposal
site. Contractor should comply with the
solid waste management regulations.
Contractor
100,000
Wastewater
Generation and
Disposal
Construction
activities
Impact on Ecology,
water and soil quality
Provide portable sanitary conveniences for
the construction workers for control of
sewage waste. A ratio of approximately 25
workers per chemical toilet should be used
Contractor
50,000
Impact on water and
soil quality
Raw materials that generate dust should be
covered or wetted frequently to prevent
them from becoming air or waterborne.
Contactor Storage of Raw
Material and
Equipment
-
Impact on water and Equipment should be stored on Contactor
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soil quality impermeable hard stands surrounded by
berms to contain any accidental surface
runoff.
Impact on water and
soil quality
Bulk storage of fuels and oils should be in
clearly marked containers (tanks/drums etc.)
indicating the type and quantity being
stored. In addition, these containers should
be surrounded by berms to contain the
volume being stored in case of accidental
spillage.
Contactor
40,000
Accidents impact on
humans and livestock
Adequate and appropriate road signs should
be erected to warn road users of the
construction activities. For example,
reduced speed near the entrance roads. This
should be done in conjunction with the
Ministry of Transport and Works.
Contactor
Impact on air quality
Impact on health
Raw materials such as marl and sand should
be adequately covered within the trucks to
prevent any escaping into the air and along
the roadway.
Contactor
Transportation
of Raw
Material and
Equipment
Impact on ambient cool The movement of equipment (trucks) during Contactor
20,000
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the construction of the plant should be
limited to the working hours, 8:00 am - 4:30
pm per day.
Impact on ambient cool Heavy equipment should be transported
early morning (12 am – 5 am) with proper
pilotage.
Contactor
Impact on health of
workers
Ensures workers health and safety through
awareness campaign and provision of
appropriate PPE
Contractor
Impact on health of
workers
Rehabilitate excavated sites as soon as
construction is complete
Contractor
Impact on health of
workers
provision of adequate sanitary facilities Contractor
Occupational
health and
safety
Accidents, fire
outbreaks
Training of all workers in Safety Health and
Environment (SHE)
Contractor
75,000
Monitoring /
inspections
Routine monitoring of the proposed actions
to ensure compliance of their effectiveness
KCWSC
AWSB
100,000
Sub Total 1 765,000
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6.2 OPERATION PHASE: ENVIRONMENTAL MANAGEMENT PLAN
Operation phase is the most critical stage as it will have long term direct reflection on quality
of environment once the project is commissioned. Main concerns during operation phase
include.
• Sludge management
• Backwash water management
• Solid waste management
• Chemical handling (Aluminum sulphate and chlorine)
• Operations and maintenance
• Emergency preparedness and response
EMP DURING OPERATION
Activity Source of Impact Anticipated
impact
Management and Mitigation Actors Cost KSH
Impact on water
quality.
Provision of solid waste storage bins and
skips.
KCWSC
Impact on water
quality.
Monitor skips so that they do not become
overfilled.
KCWSC
Solid Waste
Generation and
Disposal (wastes from
the plant screens)
general operation
of the plant
Impact on water
quality.
Ensure that the solid waste collected is
disposed of in an approved dumpsite
KCWSC
20,000
Impact on water
quality.
Alternative 1
Apply quicklime treatment to dewatered
sludge in order to create a pathogen and
odor free product.
KCWSC
Impact on health
of people around
the plant
Alternative 2 recommended
Dry sludge on the drying beds before
disposing off in a predetermined landfill
KCWSC
Impact on habitat land filling in a dedicated disposal site /
clearly designated landfill N/B the land fill
shall only be for disposing dry odourless
sludge.
KCWSC
Sludge Management De-sludging
exercise
Impact to aquatic
life
Preparation and enforcement of operational
guidelines for sludge treatment /
AWSB
100,000
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management
Impact on water
quality
Drain the waste water into an oxidation
pond / tank to allow for stabilization and
neutralization
KCWSC
Impact to aquatic
life
Alternative1
Pass the stabilized backwash water into a
soak pit or a controlled wetland before the
water diffuses underground with sand
filtration
KCWSC
Alternative 2 Recommended KWSCO
Back Wash water Filtering of the
water from the
flocculation tanks
Recycle the treated backwash water to the
channel leading to the filters
80,000
Impact on water
quality
Carrying out water sampling tests for both
bacteriological and physical element
AWSB
Improve chemical handling, avoid leakages
and spillages
KWSCO
Appropriate record keeping of data on
chemicals and material safety data sheets
Chemical Handling Chlorination
exercise and use
of Aluminum
sulphate used in
the flocculation
tanks
Impact on water
and soil quality
Awareness creation amongst workers on
proper handing of chemicals through
training.
10,000
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Impact on safety
and health of the
people
Design and implement an emergency
response plan.
KCWSC
AWBS
Impact on safety
and health of the
people
Coordinate with mutual aid
organizations/agencies such as with the
local fire brigade.
KCWSC
AWSB
Impact on safety
and health of the
people
Install fire hydrants within the proposed
development
KCWSC
AWSB
Emergency
preparedness and
response
Plant operations
Install a fire extinguisher at the plant and
train workers on how use
AWSB
30,000
Plant operations Impact on the
quality of the
environment
Motivating workers with an aim of
enhancing their contribution towards
environmental management practices
KCWSC
Plant operations Impact on the
quality of the
environment
Ensure equipment spares and protective
personal equipments are available to
workers
KWSCO
50,000
Plant operations Impact on the
quality of the
environment
Develop a database and relevant records on
environmental performance and other
monitorable parameters
AWSB
Operations and
Monitoring
Impact on the
quality of the
Activate the monitoring points as designed
in the project premises and the
KCWSC
30,000
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Environmental Impact Assessment Report for Karimenu Water Scheme
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environment surroundings
Plant operations Impact on the
quality of the
environment
Develop a database and relevant records on
environmental performance and other
monitorable parameters
KCWSC
Capacity Building Workshops /
seminars
Human resources
development.
Provide a forum for human resources
development on environmental
conservation
AWSB
KCWSC
Workshops /
seminars
Human resources
development.
Establish a schedule for continuous
improvement of human capacity on
environmental management,
AWSB
KCWSC
Workshops /
seminars
Human resources
development.
Develop in-house guidelines on
environment, health and safety
management
AWSB
KCWSC
80,000
Subtotal 2 400,000
Total
1,115,000
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6.2 DECOMMISSIONING PHASE: ENVIRONMENTAL MANAGEMENT PLAN
Decommissioning phase the stage the project has to be removed or dismantled after its
has outlived its lifespan. Before the decommissioning exercise a comprehensive
decommissioning plan has to be developed by all the stakeholders. The
decommissioning action plan has to capture all the issues that need to be handled
during the dismantling exercise.
The management has to notify responsible authorities in this case NEMA on the
intentions to decommission the facility within 1 year in order for the authority to
carryout assessment and determine potential negative impacts on environment and
therefore giving recommended mitigation measures.
EMP DURING DECOMMISSIONING OF THE PLANT
Activity Management and Mitigation Actors Cost (KSH)
Provide justification data for the decommissioning including
technical and socio-economic studies KCWSC
AWSB
Stakeholder engagement ( Liaise with the stakeholders in
identifying the need for decommissioning.
KCWSC
AWSB
Develop decommissioning Action Plan
KCWSC
AWSB
Management strategy
Obtain certificate of decommissioning from appropriate
authorities.
AWSB
To be determined then
Carryout benching and land scaping after demolition as
recommended in the audit report
KCWSC
Allow adequate base flow into the natural stream at the
abstraction units by opening up the units.
KCWSC
Conduct a comprehensive
environmental Audit
Improve on the catchments protection through planting
vegetation cover
AWSB
To be determined
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Recycling and reuse of all wastes generated
KCWSC
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6.4 MONITORING AND ENVIRONMENTAL AUDITING
There is need for an effective monitoring and maintenance schedule, which can be done
bi annually after the commissioning of the facility. The process includes continuous
improvement of the technologies aimed at improving efficiency and reducing waste.
For effective monitoring, the following must be taken into consideration
• There should be regular maintenance of all the equipment within the facility
according to operational manuals and manufacturers specifications.
• Drains at all sections of the treatment plant should be kept free of solids and
blockages for ease of wastewater flow,
• Accurate and up-to-date records on system performance should be maintained.
• Documentation plant Maintenance records should be established as forms,
system performance briefs or reports, repair expenses among others. The Plant
Manager should keep such documentation materials for reference during
monitoring activities.
It will be the responsibility of the KCWSC Management to undertake environmental
self audits as required by the law and to submit annual report to the authorities. Such
audits form the basis for monitoring the environmental performance of the plant as part
of the operation and maintenance.
Monitoring should include the following aspects;
• Maintain appropriate monitoring points in the premises to be provided for in the
plant,
• Identify the most critical parameters to monitor including among others the raw
water consumption verses output levels, waste generation trends, equipment
performance, energy consumption trends, backwash water re-use patterns,
sludge management and changes in social perception.
• Identify one or two credible laboratories for analysis of wastes at least once
every three months.
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• Carry out self-audit exercise at least once every 6 months and an annual
independent environmental audit to ensure continued compliance with
environmental regulations under the national laws. A data base would be ideal
for this purpose,
• Monitoring and audit reports should always be studied with inputs from experts
to establish performance gaps and identify suitable corrective measures
Environmental Impact Assessment Report for Karimenu Water Scheme
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CHAPTER 8: CONCLUSION AND RECOMMENDATION
From the assessment it is concluded that:
Completion of the project will have social and economic benefit not only to
Karimenu residents but also Nairobi residents as well. This will happen when
current water consumed in Karimenu is released to Nairobi
The project is appreciated by the community and other water sector players in
the project area.
From the assessment of impacts, there are more benefits to be derived from the
project implementation. Any significant negative impacts can be mitigated.
Recommendations
It will be necessary to enlist sustainable community participation by utilizing
carefully selected tools and methods to enhance local resident’s support as well
as intensifying community awareness creation and sensitization on hygiene and
sanitation
There is need to improve on the integrity of existing water distribution system
so as to minimize loss of treated water once the project is commissioned.
PHOTOGRAPHS
Plate. Description Photographs
Plate 1.
Photo showing Karimenu
River, proposed source of
water for the treatment
works
Plate 2.
Plate showing proposed
site of the treatment works
next to Aberdare forest
Environmental Impact Assessment Report for Karimenu Water Scheme
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Plate 3
Public participation
session
Plate 4
Electric fence around the
Aberdare forest. The fence
was put up to minimized
human wildlife
(elephants) conflict and
illegal logging.
Environmental Impact Assessment Report for Karimenu Water Scheme
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Plate 5
Plate showing numerous
tea plantations under the
Nyayo tea zones. Use of
Agro - chemical and poor
farming practices are
responsible for siltation
and pollution down
stream
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Plate 6
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51
Shows subsistence
farming being practiced in
the region. Residents
mainly grow cabbages
under furrow irrigation
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LIST OF REFERENCES
1) Britha Mikkelsen. “Methods for Development Work and Research: A Guide for Practioners” Sage Publications London. 1995
2) Department of Environment, the World Bank, Washington DC.
“Environmental Assessment Source Book, Volume I – Policies, Procedures and Cross – Sectral Issues” June 1998.
3) Environment Management and Coordination Act (EMCA) 1999. 4) Gerald k. Rukunga editor, “Environmental Health for East Africa. African
Medical and Research Foundation” (AMREF). Nairobi, Kenya. 5) G.M. Wamukoya and F.D.P. Situma. “Environment Management in Kenya.”
A Guide to the Environment Management and Coordination Act (EMCA) 1999”.
6) Hussein Abaza, - DTIE-ETB, UNEP: Iron Biset-BTM Cordah Limited. Bastry
Sadler – UNEP Adviser, “Environmental Impact Assessment and Strategic Environmental Assessment: Towards an Intergrating Approach.”
7) Kenya Institute of Administration, “Lecture and Tutorial Notes: Environmental
Impact Assessment and Environmental Audit Course No. 12/2004 from 16th – 26th November 2004”
8) R.E. Munn, editor, Environmental Impact Assessment (EIA), Principles and
Procedures.” Published on behalf of the scientific committee on problems of the environment (SCOPE) of the International Council of Scientific Union (ICSU) by John Wiley & Sons. Chichester. New York. Brisbane. Toronto.
9) Republic of Kenya “Environmental Impact Assessment (EIA) Guidelines
and Administrative Procedure.” National Environment Management Authority (NEMA). Nairobi, Kenya, November 2004.
10) Republic of Kenya “Community Guide to Environmental Issues and EMCA,
1999 Western Province.” Environment law project: Environmental Liaison Center International (ELCI) Nairobi Kenya, March 2005.
11) Republic of Kenya “Water and Beyond: Water Beyond the Taps.” Water
Service Boards Lake Victoria North. Newsletter issues No.2
ANNEX I Water test Analysis Report
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ANNEX II: Project Map Location
Environmental Impact Assessment Report for Karimenu Water Scheme
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ANNEX III
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Environmental Impact Assessment Report for Karimenu Water Scheme
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ANNEX IV
A RESPONSE TO COMMENTS ON EIA FOR KARIMENU BY WB ENVIRONMENT CONSULTANT The proposed Karimenu Water Supply Scheme is to be located on the slopes of the
Aberdare ranges. The source of the water supply is Karimenu River which originates
from the Aberdare ranges. The intake works will comprise of a 20m long wier across
the river and a height of 2m. the wier is located within the forest but the treatment plant
is outside the protected forest. The location of both intake and treatment works was
arrived at after consultations with the Kenya Forest Service (KFS) – Government
Department responsible for management of gazette (protected) forests. A permit to
construct the weir was obtained from KFS on the same.
A survey was conducted during the EIA preparation during which the views of the
communities along the river were solicited. Structured questionnaires were used and are
available if needed. The findings showed support of the project by the community that
hitherto is supplied with raw water from Karimenu River. It is for this reason that the
project will now introduce treated water to its consumers and hence reduce cases of
water borne diseases in the project area.
Karimenu water supply is an old Government operated scheme where raw water from
Karimenu River is supplied to the consumers. Recent growth in population and
increased Agricultural activities in the project area has necessitated treatment of the
water supplied to consumers. This is the main reason of locating the intake within
protected forest area where pollution from human activities is and will remain minimal
in the future.
Karimenu water project has no direct link to Thiririka and Ndarugu as the three sub-
projects have different water sources.Each of the sub-projects derives its name from the
respective name of the River. The purpose of clustering them as one project under the
name: Independent Mataara Production Mains was informed by two main reasons
namely;
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• Ease of contract administration of these sub-projects under one supervision
contract and one construction contract.
• The sub-projects have one common objective of having independent water
sources so that more water can be released to Nairobi city. Hitherto, water
transmission pipelines to Nairobi traverse these areas and some of the water
targeting Nairobi city has to be distributed in these localities thus reducing
available water to Nairobi city.
International Water ways
The proposed Karimenu water project does not trigger the international water ways
operationa policy in anyway and has no correlation with Lake Victoria that is an
international water source. Karimenu River joins Chania River which eventually joins
Thika River and drains into Athi River and eventually Indian Ocean.
B RESPONSE TO COMMENTS ON EIA FOR KARIMENU BY WB ENVIRONMENT CONSULTANT
Karimenu Water Supply Scheme is an old government project that was constructed in
the early seventees to supply water to residents of larger Gatundu district. The project
supplied raw water to residents as water then was free from contamination. Up to now,
the project still supplies 9000m3 of untreated water per day to consumers.
It is for the above reason that the proposed plant is being set up to treat the authorized
9000m3 of water which is currently being abstracted and distributed raw. No additional
abstraction from the river will be done and therefore river flow downstream will be
maintained. Nevertheless, normal river flow measurement is periodically done by
Water Resources Management Authority and this information will be in cooperated in
the project progress reports.
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ANNEX V
KARIMENU WATER SCHEME GATUNDU NORTH DISTRICT
RESPONSE TO NEMA REMARKS ON ENVIRONMENTAL IMPACT ASSESSMENT PROJECT REPORT: NEMA REF NO: 0282
ISSUE TO BE ADDRESSED: WATER TREATMENT METHOD
Introduction Karimenu Water Treatment Scheme is designed to abstract water from Karimenu River which is a tributary of Thika River. The plant is divided into two sub plants one of which is expected to produce 9000 m3/day and another smaller plant to produce 2000m3/day.
Originally, water from Karimenu River was fresh and clean, but due to human settlement in recent years and wildlife grazing upstream, contamination is evident as indicated in the water analysis conducted by Central Water Testing Laboratory which shows presence of general coliforms.
It is for this reason that Athi Water Services Board is planning to set up a water treatment scheme to ensure water supplied to consumers is safe for human consumption. The method of treatment is the conventional water treatment procedure as outlined from the steps below: (See schematic diagram)
Intake Weir (Karimenu River)
Water flows by Gravity to consumers
• Intake weir • coagulation/flocculation • Sedimentation, • Filtration, • Stabilization, • Fluoridation and Chlorination.
Intake weir Water is abstracted through intake weir raised 2 inches above water level, water then flows through the intake mains by gravity to the flash mixer where Alum is added before flowing to the flocculation basins.
Coagulation / Floculation
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In the coagulation/flocculation process, very fine suspended particles are caused to come together to form larger particles that can be settled and filtered out of the water. These include fine silts, bacteria, color causing particles and viruses that might not settle for days, months or even years. Although individual particles cannot be seen with the naked eye, their combined effect is often seen as cloudiness, or turbidity, in the
water. These particles are small enough to pass through later treatment processes if not properly coagulated and flocculated. This could adversely affect not only the clarity of the water, but its taste and odor, as well as the effectiveness of chlorine disinfection.
During coagulation, the chemical Aluminum Sulfate, or filter alum, is added to the incoming raw water (untreated water from the river). The water is stirred vigorously in a flash mixer to assure quick, uniform dispersion of the alum. The alum reacts rapidly with compounds in the water that contain carbonates, bicarbonates and hydroxides to produce a jelly-like substance that absorbs impurities. At the same time, alum, with a positive charge, neutralizes the negative charge common to natural particles, which draws them together. Small particles called microfloc are formed. The following equation shows the reaction of alum with alkalinity:
Al2(SO4)3 . 14H2O + 3Ca(HCO3)2 2Al(OH)3 + 3CaSO4 + 6CO2 + 14H2O
Aluminum Sulfate Calcium Bicarbonate Aluminum
Hydroxide Calcium
Sulfate Carbon Dioxide Water
The water moves from the flash mixer to the flocculation basins which contain horizontal paddle systems. The basins provide a gentle, constant mixing of the microfloc formed during coagulation. This stirring promotes formation of larger and heavier floc. After 20 to 30 minutes, the floc particles are usually visible and will look like tiny tufts of cotton or wool, separated by clear water. Once the flow is of sufficient size and density to be settled, the water moves into the sedimentation or settling basins.
Sedimentation Sedimentation is the removal of solids from water by gravity settling. Basins are designed to hold large volumes of water for several hours and to give a smooth, even flow. This design allows the velocity and turbulence of the water to be decreased to the point that the water will no longer transport the flocculated solids and they will settle to the bottom of the basin.
At the end of the settling basin, hydrated lime, Ca (OH) 2, is added to the water to increase its pH. This is necessary because the alum that is added during the coagulation/flocculation process is acidic.
Filtration The water flows from the sedimentation basins into the filter beds. Filters contain material of graduated size in layers that remove solids from the water. The first layer of filter is gravel and the second layer is filter sand. Under the sand is a layer of stone or plastic composite. At the bottom of the filter is an underdrain system that supports the filter.
Water gravitates onto the filters, leaving behind suspended matter as it passes downward through the filter. Solids that are larger than the pores or holes between the grains are captured by the filter. Also, some suspended matter adsorbs, or sticks to the surface of the filter or the previously deposited material.
After a period of time, the accumulated solids begin to clog the filter, so the filter is backwashed. Backwashing is the reversal of the direction of the water flow through the
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filter. A rapid upward flow lifts the particles and keeps them in suspension until they can be washed out.
Following filtration, the water flows underground into a storage tank called a clearwell. Water leaving the clearwell is stabilized, fluoridated and chlorinated in-line on the way to the distribution pumps.
Chlorination Chlorination of public water supplies is the most important process used to produce safe drinking water. A sufficient amount of Sodium Hypochlorite, essentially strong bleach, is added to the finished water so that a minimum amount of chlorine remains in the water until it reaches the customer's tap. Chlorine is necessary for disinfection of water before it is release to the consumers, chlorine will be responsible for killing all the general coliforms and E – coli identified in the water by the Central Water Testing Laboratory sampling reports. Distribution After the final addition of chlorine, the water is released by gravity to the pipes that lead to the customer's tap. Chlorine is re-injected into the system to address issues of re contamination for system running for long distances.
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