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Has WRMA licensed the Northern Collector Tunnel Project?
Frequently
asked
uestions
KENYA’S BIGGEST
WATER PROJECT:
THE NORTHERN WATER
COLLECTOR TUNNEL PROJECT
What is the Northern Collector Tunnel?
In line with Vision 2030, the Government of Kenya plans to
improve water services in Nairobi City, Kiambu and Muranga
Counties. One of the key ways of improving water services is
through the construction of the Northern Collector Tunnel Phase
1(NCT 1) scheme.
Athi Water prepared a water masterplan for Nairobi and 13
Satellite towns in 2012. The masterplan provides a blueprint for
progressive and phased development of water sources to meet
the demand in those areas upto 2035. The first phase of the
masterplan has been implemented while the Nothern Collector
Tunnel (NCT 1) is under Phase 2 of the masterplan. Phase 3
includes Maragua dam and transfer of water through a tunnel
from South Mathioya River. Phase 4 will be NCT 2 which will
transfer water from 3 rivers namely North Mathioya, Hembe and
Githugi river to Ndakaini dam and Maragua dam, and Phase 5
will be the construction of Ndarugu 1 dam.
NCT 1 will entail the construction of 11.8km raw water transfer
tunnel along the Eastern fringes of the Aberdare Conservation
Area (60Km North of Nairobi), to divert defined flows from
Maragua, Gikigie and Irati rivers into existing Ndakaini dam
plant and subsequent transmission through 1200mm diameter
pipeline to Kabete water reservoirs via Gigiri to supply the
upper zones of Nairobi. The project will improve water supply to
Nairobi City by 140,000 cubic meters per day.
The tunnel will serve the following purposes: 1. Flood control, and
2. To abstract flood flows to Ndakaini dam. The NCT 1 tunnel will
utilize flood waters for domestic and industrial use in Nairobi and
neighbouring urban areas.
How is the Northern Collector Tunnel Designed?
The proposed major elements of the project include diversion and
intake structures at those three rivers (Maragua, Gikigie and Irati),
an outfall at Githika River near Thika reservoir at Makomboki, and
Kaanja Access Adit. Once completed, the supply of water to
Nairobi residents will increase by about 140,000 cubic meters per
day, reducing the daily shortfall to 60,000 cubic meters per day.
The operating principal is such that once Ndakaini Dam is full the
tunnel is designed to have shut-offs mechanism to protect the dam
and downstream communities. Water is again drawn from the 3
rivers after average normal flows (Q95) has been achieved or
exceeded and compensation for downstream users and ecological
needs have been prioritized and before any abstraction through
the tunnel. The tunnel is designed to draw water from the three
rivers, especially during flood periods, and to quickly fill up
Ndakaini dam. Once the dam is full, no more water is drawn from
the three rivers until designed dam drawdown is achieved.
Gikigie Intake/Access Adit
Irati River
Kaanja Adit Portal
Makomboki Outfall
Thika Dam
Project Area
ViewViewofof project
area
How is the NCT 1 different from the design of Ndakaini Dam
to Ngethu Treatment Works system?
The design for NCT 1 intakes at rivers Maragua, Gikigie and Irati
is different from that which was previously constructed on the
existing Ndakaini Dam to Ngethu Treatment works system.
Athi Water has been keen to improve on technology and innovation in order to develop systems that take into consideration of
social and environmental concerns. The NCT 1 systems have been
designed with downstream reserve flows being first priority
whereas intakes in the earlier system considered abstraction for
supply as the first priority.
Also the system did not take cognizance of the water needs for
surrounding communities. NCT 1 has provided for construction of
community water schemes to supply water to communities at
Ndakaini and other parts of Murang’a and will improve provision
of clean water by 17,000 cubic meters per day and lay 247km of
water pipelines at a cost of KSh. 1.4 Billion.
Have consultations been done for the project?
Athi Water carried out and has to date continued with
stakeholder’s consultation and public engagement. This is a
process that was carried out with enthusiasm during the feasibility
study and master plan preparation phase, the EIA and resettlement action plan (EIA) preparation phase and the preliminary
design and detailed design phase.
The concerns of the stakeholders were considered and addressed
in the reports. At the implementation phase, stakeholders, key
among them Muranga County Government will be involved in
monitoring of the project to confirm that the designs including any
reviews that would enhance social and environmental safeguards
are implemented in the works.
Athi Water has continued to regard and keep the minutes of
stakeholder’s consultative meetings that were conducted.
What is Flood Water?
Flood water is generally defined as flows more than Q80 or simply
flows that are equalled or exceeded 80% of the time at a particular point in a river. The NCT 1 will abstract flows higher than the
average normal flows or Q95 for Maragua and Gikigie Rivers and
1.4Q95 for Irati River. This will ensure that the downstream demands
(reserve flows) is sustained to meet requirements of downstream
users and the ecology.
Has NEMA licensed the Northern Collector Tunnel Project?
The Northern Collector Tunnel 1 works have been issued with an
EIA Licence by NEMA. And whereas this has been contested in the
National Environment Tribunal, Athi Water is keen to adhere to
the conditions of the licence and comply to the requirements as a
condition process.
Athi Water has fast tracked the implementation of the Murang’a
community water projects with the understanding of Murang’a
County Government that these benefits are to the local community as
a result of the NCT 1 project. The projects are Murang’a community
project ( includes Kiriciungu treatment works supply, Kahuti phase 2
water treatment works supply, and storage and extension of water
network distribution system), Gatanga community water project,
Gatango community water project, and Kiruri, Ichichii and Makomboki community water project.
The Muranga County Government has granted the no objection to
construct the contractor’s camps, sites offices and houses at Kinyona,
Mununga and Gikoe dispensaries and to upgrade Gikoe dispensary. The dispensary committees for the three facilities have also
given Athi Water authority to proceed with these works. The
upgraded dispensary will provide better medical services to the
project staff and the community. These facilities, including an ambulance to be brought under the project, will be handed over to
Muranga County Government on completion of the project.
Irati Intake & Shaft
Thika River
When will the Murangá Community Water Projects start?
Has Murangá County Government Granted Construction
of the Site Offices?
Maragua Intake
Maragua River
Gikigie River
AWSB has made an application to Water Resources Management Authority (WRMA) for water abstraction permits from the
three rivers (Muranga, Gikigie and Irati) after receiving the
NEMA licence for the Works. Construction works will commence
at these sites once the WRMA permits have been issued. The land
required for the works at the three rivers has been acquired and
compensation to landowners is almost completed. In the
meantime due to the high scale of pre-construction work
required; Athi Water through a contractor is currently undertaking preparation works including contractor’s camp sites and
offices. A contractor camp site, spoils area and access road are
also under construction at Makomboki site.
Will the tunnel tap into the ground water systems?
Athi Water as a public body and state corporation is committed to
uphold the rule of law and comply with statutory requirement in
undertaking the Northern
Collector
Maragua
River Tunnel and any other project.
WET WEATHER FLOW
DRY WEATHER FLOW
Maragua river facing downstream from the bridge
Irati river view upstream from bridge
Maragua river view
Irati river view (pipe submerged)
Who is funding the Northern Collector Tunnel 1 and the
Community Water Projects in Murangá?
The Northern Collector Tunnel project is one component of the
Fourth Nairobi Water Supply Project that will include Kigoro
Water Treatment Plant of capacity 140,000m cubic meters per
day, 6Km by 1200mm diameter gravity pipeline from Thika Dam
to Kigoro and 60Km by 1200mm diameter clean water transmission pipeline from Kigoro to Kabete and finally improvement of
the Nairobi Water Distribution System.
The Fourth Nairobi Water Supply Project is supported and
financed by the Government of Kenya, the World Bank, the
French Development Agency (AFD) and the German Government
Development Bank (KfW).
The World Bank has carried out review of the project documents
and continues to review activities by Athi Water that relate to the
financing portfolio. With the support of the Government of Kenya
and the World Bank, Athi Water is keen to ensure that social and
environmental mitigation measures, to prevent adverse social or
negative environmental impacts as outlined in the Environmental
and Social Impact Assessment (ESIA) report, are implemented.
Has Athi Water reached out to Maragua Water Resources
What benefits will Murangá residents get for the NCT project? Users Association?
Through the implementation of the NCT 1 project, communities in
Murang’a will derive benefits through the implementation of
community water projects. The community water projects will cost
KSh. 1.4 Billion and this has been leveraged on the KSh. 6.8 Billion
NCT 1 project (14.7% of the NCT 1 project cost). This projects will
improve clean water supply by 17,000 cubic meters per day and
extend water supply network by 247Km to benefit more than
600,000 people in Murang’a with improve water services. A map
of the areas to benefit is available at the office of the Muranga
Water Supply Resident Engineer located opposite the Muranga
County Commissioner’s residence, Murang’a town (next to
Murang’a University of Technology. Further to this, Athi Water is at
the final stages of securing financing amounting to KSh. 1.4 Billion
for water services improvement in Ithanga which is a semi-arid and
dry area of Muranga County and has over the years had severe
water supply problems.
Why doesn’t Athi Water Build a Dam Downstream to tap the
Flood Water?
The NCT 1 tunnel has complete concrete lining to prevent ingress of
the ground water into the tunnel. The tunnel will therefore not affect
ground water system in any way. Tunnel construction technology is
not new and has been used widely especially in developed
countries in roads, railways and inter-basin water transfer without
any effects on ground water system.
By constructing a dam downstream of the tunnel, flood flows will be
harnessed and stored for use during the dry spell. This is why Athi
Water is preparing the development of Maragua dam on Maragua
River to harness the excess flows downstream of the tunnel abstraction point.
There is an existing 4Km tunnel conveying water from Ndakaini dam
to Chania river that was constructed in the early 1990s under the
Third Nairobi Water Supply project. No reports of any negative
impace has been reported to date as a result of this tunnel on
ground water system even though the tunnel was not fully lined.
Murangá County Government would also benefit by constructing
dams downstream of the tunnel to ensure water security in the county
even in times of prolonged dry weather. This will then ensure that
planned irrigation schemes are successfully implemented. Planning
for irrigation without construction of dams may not be sustainable
even without the NCT 1 project.
Athi Water has been in discussion with the upper Maragua Water
Resource Users Association in an effort to assist the WRUA’s
prepare a catchment management proposal for submission to the
World Bank financed Kenya Water Security and Climate
Resilience Project at the Ministry of Environment, Water and
Natural Resources. The proposal will be submitted to Water
Resources Management Authority (WRMA) for consideration.
Athi Water believes that without protecting the catchment which is
heavily degraded and devastation continues each year, thinking
of adequate water supply for domestic use, let alone for irrigation, is not realistic. There is need for all stakeholders to work
together towards protecting the Aberdare forest water tower. Athi
Water is keen to see that the NCT 1 water supply is a sustainable
investment for the future of Murangá and Nairobi City County.
Why is NCT 1 project important?
Currently Nairobi City County faces a water demand to supply
gap of over 200,000 cubic meters per day. By developing the
NCT1 project this demand gap will be reduced by 140,000 cubic
meters per day. Otherwise the Nairobi City County that is an
economic hub will face serious water shortage in years to come.
Close collaboration between Nairobi City County and Muranga
County, not forgetting Nyandarua County where Sasumua Dam is
located and Kiambu County where Ruiru Dam is located, is fundamental and imperative for the economic development of the
respective county governments.
Have detailed studies been done on the Northern Collector
Tunnel?
At the feasibility study and preliminary design stage, Athi Water
undertook detailed social, environmental, extended yield analysis, and ecological studies and prepared reports. These reports
were reviewed at the Environmental Impact Assessment Report
and detailed design preparation stage. The designed intake
structures were revised and adjusted to meet the requirements of
the revised hydrological analysis report.
The hydrological analysis has been done based on existing
regulations and observing requirements by Water Resources
Management Authority (WRMA) on reserve flows and abstractions. Should Water Resources Management Authority (WRMA)
recommend other adjustments to the design, Athi Water will
consider and review the design. Currently, the hydrological
report has considered all water rights (current and future)
provided by Water Resources Management Authority (WRMA)
for to the three rivers.
What is the Average Annual Maximum Flow in the 3 rivers?
The average annual maximum flow in the 3 rivers (Murangá, Gikigie
and irati) is 1,198,368 cubic meters per day while the maximum
proposed tunnel abstraction is 513,389 cubic meters per day. This
means the flow downstream will be 684,979 cubic meters per day
against an analysed reserve flow of 110,333 cubic meters per day.
This scenario is evident during the rainy seasons when the water level
is high in all three rivers. This is the flow that the NCT 1 targets in
order to quickly replenish the draw down in Thika dam. When the
normal flows are restored, the NCT 1 project will only draw water
from the rivers once the compensation flow are achieved and there
is surplus flow to flow into the tunnel draw off chamber.
This means:
1.
Total average annual maximum flow = 437,404,320
cubic meters per year.
2.
Proposed NCT abstraction (maximum) = 187,386,912
cubic meters per year
3.
Balance flow downstream = 250,017,408 cubic
meters per year
4.
Instream Flow Requirements/Reserve flow (estimated)
= 40,271,545 cubic meters per year
Will the rivers dry up?
There is no time that the flow downstream of the abstraction
points will be zero (except in the extreme condition where no
water is flowing from upstream of the tunnel abstraction point).
The design is such that the first priority is reserve flow
(compensation flow and ecological flow requirements) and once
this are met, the tunnel will receive water at the intake. The
tunnel has been designed with proposed maximum amount of
water that can be abstracted at each river (Muranga 3m3/sec, Gikigie - 0.975m3/sec and Irati - 1.967m3/sec). This
will ensure that on average (annually), a maximum of
250,017,408m3/year will flow downstream of the tunnel
abstraction point (94,608,000 m3/year - Maragua,
30,747,600 m3/year - Gikigie and 62,031,312 m3/year Irati).
Will there be water for the future generations of Murangá residents?
Water allocation guidelines by the Water Resources Management
Authority (WRMA) have been observed in the NCT project design.
In estimating the water demand requirements for Muranga, Athi
Water accessed information from the Water Resources Management Authority (WRMA), Muranga office, relating to current water
rights and those that have been received by the office. The NCT 1
has taken into consideration reserve flows for future water demands
and water rights downstream of the tunnel.