The GOK with the support from the World Bank has been implementing the Water and Sanitation Service Improvement Project (WaSSIP). The Government has now secured further financing from the World Bank under the Water and Sanitation Service Improvement Project Additional Financing (WaSSIP AF) project that was made possible because of the satisfactory implementation of the ‘original’ WaSSIP and its contribution to water services improvement.
AWWDA is using part of the WASSIP AF funds to implement the Northern Collector Tunnel Phase 1. The project is derived from Nairobi Water Master Plan for Developing New Water Sources for Nairobi and 13 Satellite Towns namely Kikuyu, Ruiru-Juja, Kiambu, Karuri, Githunguri, Mavoko Municipality, Ngong Township, Ongata Rongai, Thika, Gatundu, Limuru, Lari and Tala-Kangundo. The Northern Collector Tunnel Phase 1 includes river diversion weir and related intake hydraulic structures at Maragua, Gikigie and Irati Rivers as well as construction of river outlet at Githika River which will convey the additional water to Thika dam. The tunnel is approximately 11.8km long and of 3m finished internal diameter. The objective of this project is to increase water supply in Nairobi County by 121,000m3/day.
In order to effectively monitor the impacts of the tunnel works on the groundwater, AWWDA has prepared a baseline survey of all wells and boreholes along the Northern Collector Tunnel project.