The National Water Master Plan Sectorial Report on 1992 identified three sites along the Athi River Basin (Munyu, Baricho and Thwake) having potential for water supply, irrigation and power development. The Government of Kenya (GoK) later conceptualized Thwake Multipurpose Water Development Program (TMWDP) as one of the critical water reservoirs (dams) to help the Semi Arid counties of Machakos, Kitui and Makueni to address perennial water challenges for the rural communities. The goal was to generate hydro-power and provide irrigation water to improve food security for residents. The Program is aligned to the Kenya’s Vision 2030: The economic and social pillars of Government of Kenya’s Vision 2030 and Kenya’s Medium Term Plan II 2013 – 2017 (MTP-II) acknowledge Kenya as being a water scarce country and both underscore the central role water plays in the performance of key sectors of the economy.
It is one of the largest dams in Kenya and once complete, it will store 685 million cubic metres of water.