The Government of Kenya through the Ministry of Water, Sanitation and Irrigation is implementing Thwake Multipurpose Water Development Program. This is a Flag Ship Program under Vision 2030 of the Government of Kenya (GOK) and a key project under the Government Big Four agenda. The program comprises a multi-purpose dam for water supply, hydropower generation and irrigation development. It will also provide regulation of flows on River Athi downstream of the dam for flood control and drought mitigation

The dam is located immediately downstream (~1km) from the confluence of Athi and Thwake rivers in Mavindini Division (on the Makueni side) and Kanyangi Division (on the Kitui side) while the flow back will extend into Kathulumbi Division of Mbooni district to the northwest of the dam site.

Phase 1: Construction of an 80.5m high multi-purpose dam with storage capacity of 688 million cubic metre and associated preliminary works located one Kilometre downstream of the confluence of Thwake and Athi Rivers. It is an embankment dam with an approximate maximum height of 80.5 m covering an area of around 9,217 acres, with catchment spanning about 10,276 km2

Phase 2: Development of Water Supply, Sanitation & Waste Water Infrastructure to supply estimated 150,000 m3/day of treated water to approximately 1.3million people drawn from the rural areas of Kitui and Makueni Counties and Konza Techno City in Machakos County

Phase 3: Development of hydropower generating system with an installed capacity of approximately 20 MW

Phase 4: Development of Irrigation Scheme to ultimately irrigate 40,000 hectares (approx. 100,000 acres) of land

The dam will provide treated water to approximately 1.3 million people thus contributing to universal health care by reducing water borne diseases. Areas of coverage will include:- Wote Town, Kitui rural up to Kwavonza sub-urban center, Makueni rural covering Mavindini and Kalawa sub-urban centers, Kathonzweni Town and provide bulk water supply for Konza Techno City for domestic and industrial use. Sewerage infrastructure will be developed in Wote and Kibwezi towns.

Yes. Most labour force is sourced from the local community in the counties of Makueni, Kitui and Machakos – skilled and unskilled. It is anticipated that approximately 8,000 jobs will be created directly and indirectly during the course of the program implementation.

Yes, it will be treated before it reaches residents. More so, some of the ongoing initiatives to control pollution of Athi River include identification of pollution hotspots identified and mapped by Water Resources Authority (WRA) and National Environment Management Authority (NEMA), Athi Water Works Development Agency has put up 19 ablution blocks in Kibra slums and in partnership with Mazingira Yetu undertaken River clean up exercise, Water Resources Authority has pegged some riparian areas and is in the process of pegging more areas for protection while there is an ongoing project of sewerage connections in Kasarani area, Nairobi.
Already, a multi-sectoral (inter-agency) committee drawn from a number of players and institutions is in place to spearhead catchment protection and pollution control activities on Athi River. The team is mandated to generate possible action lines that will be implemented to control pollution problems in Nairobi Basin Rivers which feed into the Thwake Dam. The team includes Ministry of Water, Sanitation and Irrigation, National Environment Management Authority (NEMA), Athi Water Works Development Agency, Nairobi Water and Sewerage Company, Nairobi Metropolis Services (NMS) and Water Resources Authority (WRA).