The Gatharaini trunk sewer project is located in Ruai, Gatharaini South, Gatharaini North, Clay works, and Ruaraka areas of the City of Nairobi. The lower reaches of the Gatharaini sewers are accessible from Kagundo Road while the upper reaches of the trunk sewer are accessible through the Nairobi-Thika road and the Kamiti road.
The works being undertaken under in this Project comprise of various trunk sewers, covering about 50 km2, as follows:
i. Ruai Outfall Trunk Sewer: This sewer stretches from the outfall manhole MH 127 on the Dandora Estate Trunk Sewers to manhole GMH-01 of Gatharaini North Trunk Sewer near the railway bridge situated between Mwiki and Githurai 45.
ii. Gatharaini North Trunk Sewer: The Gatharaini North Trunk Sewer stretches RuaiOufall Trunk Sewer at manhole GMH-01, near the railway bridge situated between Mwiki and Githurai 45 to Mururui Estate, to Mururui Estate, for a distance of about 9,332m. The trunk sewer therefore drains into the Ruai Outfall Trunk Sewer.
iii. Gatharaini South Trunk Sewer: The trunk sewer stretches from Manhole GMH-13 of the Gatharaini North Trunk Sewer and traverses Mwiki Estate, Kasarani Stadium, ICIPE, across Thika Highway and Safari Park hotel to Thome estate. The total length of this trunk sewer is 8,212 m.
iv. Clay Works Trunk Sewer: The Clay works trunk sewer drains into Manhole GMH43 of the Gatharaini North Trunk Sewer and it passes through Clay works estate, Thika Highway before terminating at Zimmerman next to Kamiti road. The total length of this trunk sewer is 3,000 m.
v. Ruaraka Trunk Sewer: Ruaraka trunk sewer runs from Allsopps area, next to Kenya Breweries, through Garden Estate to Ridgeways. The total length of this trunk sewer is 3,299m.
vi. Secondary Sewers: The works on the secondary sewers will involve construction of approximately 23km of concrete pipes of diameter ranging from 300 mm to 450 mm and 347 manholes.