Ministry of Water and Irrigation together with Athi Water held a groundbreaking ceremony at Theta Dam site on 11th March 2011. Theta dam, located inside Kinale Forest, is being constructed across Theta River in Gatundu district, Gatundu South constituency, and accessed through the Gatundu – Kiganjo – Mundoro tarmac road. It is approximately 7km from Mundoro trading center. The project costs Kshs 450 Million and includes construction of a 17 meter high compacted earth fill dam, Construction of a reinforced concrete spillway and Laying of a 3.5km long 500mm diameter steel pipeline up to the Mundoro forest edge.
On completion, Theta dam reservoir will have a storage capacity of 2 million cubic meters (2 Billion liters). This will enable production of 15,000 m3/day of water that will augment both the Ndarugu and Thiririka water projects reliability. This will improve water supply to the upper parts of Gatundu such as Gachika, Kiamuoria, Kiganjo, Gatitu of greater Kiganjo location and upper parts of greater Ndarugu locations.