This is the largest and most successful irrigation scheme in Kenya, covering about 10,000 hectares.
It is located in Mwea Plains in Kirinyaga County. Water for irrigation is drawn from rivers Nyamindi, Murubara, and Thiba, all of them tributaries of river Tana.
The scheme was established during the emergency period in the 1950s as a way of utilizing free labour provided by the mau mau detainees.
The original location of the scheme was at Nguka, a flooding point of river Thiba. This formed the first block (Mwea Block).
Two other blocks, Thiba and Wamumu were established southwards. Later, a fourth block was established (Tebere) to utilize the waters of River Nyamindi