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Thwake Water Supply & Sanitation Project


  • Référence: P-KE-E00-008
  • Date d’approbation: 30/10/2013
  • Date de début: 25/11/2014
  • Date d'évaluation: 08/06/2013
  • Statut: En coursOnGo
  • Agence d'implémentation: MINISTRY OF WATER DEVELOPMENT
  • Emplacement: Kitui, Makueni, KENYA



The development goal of the water sector in Kenya, is improved the health, quality of life and a cleaner environment through provision of safe and sustainable water and sewerage services. The plan is to increase the amount of water available to the population that can be used for domestic, irrigation and hydropower generation through construction of a multipurpose dam on the Athi river. This will lead to improved livelihoods and environment, together with improved productivity of the population, among other benefits.

The immediate objective is to increase the availability and access to water for domestic and productive use.

Scope Description

The Thwake water and Sanitation project will cover four major areas of intervention

(i)Dam construction.

(ii)Provision for power generation capability on the dam;

(iii)Irrigation canals and off take facilities from the dam; and

(iv)Rural water supply schemes sanitation facilities.


Preliminary investigations indicate that a high dam (84m high) is feasible on the proposed site. The dam has been designed for full reservoir storage of 825mcm with live storage of 594mcm. The reservoir will cover an area of 2,933ha at full storage. The embankments will require about 18.4 Mm³ of earth fill materials. The crest of the main dam will be 1,600m long.

The total rated capacity of the power supply component is 20MW. Two turbines with rated capacity of 10MW each have been recommended. The gross operating head will vary between 70m and 50m, and at times it will be necessary for the turbines to function below their rated capacity.

The water supply component of approximately 300,000 m3/day will serve population living in an areas of approximately 550 km2 in Mavindini, Kanithuni, Kitise, Kithuki locations and parts of Kathonzweni and Mbuvo locations in Makueni district, lower Yatta in Kitui district and proposed Konza ICT city in Machakos district. It is estimated that at the ultimate design period in 2030 the project will benefit some 2,000 ,000 people. The project will also provide for water borne sewerage facilities for Wote, Kathonzweni, Makindu Kibwezi towns Mtito-Andei and proposed Konza ICT city. The Thwake project does not include construction of the rising mains for supply to the Konza ICT city, it will be funded from the GoK support independent of this project.

Concerning water for irrigation, the dam will supply 24,000 m3/day of water to new irrigation schemes targeting the small scale farmers. It will also be used to stabilize the flows for the downstream irrigation scheme at Kibwezi. The Kibwezi scheme will be a secondary beneficially as it will draw the water after being released from the dam. The Kibwezi scheme covers an area of approximately 21,000 hectares which is divided into four blocks of varying acreage. The scheme is located in Ngwata Location in Kibwezi District 90 km downstream of Thwake dam site. Besides there is adequate arable land downstream which with improved flows in the river is likely to be developed for irrigation. The dam will benefit small scale farmers through provision of irrigation canals.


The Thwake Water and Sanitation Project should be supported for a number of reasons:

i).This project fits within the pillar-I of the Bank's current 2008 - 2012 CSP for Kenya. Pillar I focuses on supporting infrastructure for enhanced growth. The infrastructure developments in this project such as a dam, water supply schemes, sanitation facilities, hydro power, and irrigation canals are contributing to the medium to long term strategy of improved infrastructure services for competitiveness. The Vision 2030 also acknowledges the importance of investing in water and sanitation sectors as infrastructure developments for growth and productive livelihoods. The GoK in its First Medium Term Plan Update of the Vision 2030 has committed itself to continue allocating adequate resources for water programs in the arid and semi-arid areas in order to better cope with climate variability, enhance food security, and provide opportunities for the vulnerable members of society in the regions.

ii).The project also fits in the Bank's Medium Term Strategy (2008-12) that aims at providing for the support and capacity of RMCs to sustainably manage water resources and mainstream Integrated Water Resources Management (IWRM) practice. The project addresses both the infrastructure improvement and capacity building targets of the MTS, the CSP and MTP.

"The project is located in a semi-arid area where lack of water has greatly limited development. Thus, the inhabitants are supportive to the development of the proposed dam.

"Due to lack of water, poor sanitation is prevalent. Diseases such as malaria, typhoid, amoeba, skin ailments and cholera are common in the area.

"People spend a lot of time searching for water for domestic use and for livestock. In the dry seasons, in particular, people cover long distances (over 15km) to get to the nearest water source.

"Food security in the area is uncertain. The situation is likely to improve with supported irrigated agriculture from the dam project. Farming will create employment and also improve the people's incomes.

"The GOK has initiated the development of the Koza ICT City, a high-tech development which is targeted to benefit from the proposed Thwake project for its water supply. The Thwake project therefore fits very well with the country's vision of establishing an ICT City and the successful implementation of that vision rests on the implementation of the Thwake project.


Thwake dam will supply water to the target areas of Wote, Kathonzweni, Kitise, Mavindini and Kalawa divisions among others whose main constraint to development has been scarcity of water which has contributed to hardship and low income of the people within the area. This will have major positive impacts on people's livelihoods, incomes and food security.

Provision of water from the proposed dam has the potential to enhance development and growth of the markets as more economic and social interests arise. There will be other indirect benefits such as environmentally sound waste disposal site and improved sanitation practices hence reduction of some diseases such as malaria, typhoid and others.

The generated power will be a contibutor to the power pool of the country which is currently defient and will contribute to the social and economic welfare of the country.

Contacts clés

MUTASA Christopher - RDGE2


Source Montant
FADUAC 62.890.000
GovernementUAC 116.400.000
TotalUAC 179.290.000
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