Masinga Dam

Name of Project:
Masinga Dam


Tana River Development Authority

Construction period:
1978 – 1982

Effect of the new dam: Erection of the multi-purpose reservoir for the Masinga Dam and equipping it with a medium pressure system comprising 2 Kaplan turbines with 20 MW each, including a detention reservoir for the project with a capacity of 1,560 million cubic meters, affected the environ¬ment in the following ways.

Flood water resulting from the two rainy seasons in the upper reaches of the river system is stored in a detention reservoir and released in the dry period as required, thus taming the natural supply of water, which fluctuates extremely, depending on the time of year, and retaining it for future use.

Optimum and steady loading of the downstream power plant turbines at Kamburu, Gitaru and Kindaruma is guaranteed, even in the long dry season, by re-leasing 2 x 45mof water per sec. through the Masinga turbines, which is the maximum theoretical flow normally. This figure also takes into account the infiux of the Thiba River at an average of 10 m3 per sec. and the capacities of the downstream continuous storage basins.

An additional 12,000 hectares of land could be irrigated within the reaches of the detention basin. Improved exploitation of the existing irrigation system in Bura Hola is achieved, since the amount of water supplied re¬mains constant throughout the year, making it possible to have more than one harvest per year, incidentally.

The upper reservoir capacity also provides for flood water protection, to a certain extent, for the lower course of the Tana River.

The 45-km-long and 120-sq-km large lake is the basis for creating a local fishing industry for Nairobi and the surrounding area.

Main characteristics:
  • Dam Location: Masinga on Tana River/Kenya 165 km East-North-East of Nairobi
  • Tana River Upper Reservoir Scheme: Multi-purpose/ Power Generation and Irrigation
    Upper Reservoir length: 45 km
    Upper Reservoir Area: 120 sq. km
    Total Capacity: 1,560 x 106 m3
    Dam Catchment Area: 7,335 sq km
  • Embankment Dam
    Main Dam length: 2,220 m
    Main Dam height approx.: 60 m
    Saddle Dam length: 400 m
    Saddie height approx.: 18 m
  • Concrete Works
    Spillway length: 676 m
    Spillway shute width: 30 m
    Spillway plunge pool: 120 m
    Emergency Spillway: 1 u 
  • Intake
    4 Towers, height each 61 m  
    Steel Pressure Conduits: 2 u
    Diameter each: 3,5 m
    Length: 231 m 
  • Low Level Outlet
    Length approx. partly with Steel-Liner 225 m 
  • Two Surge Chambers height each 65 m
  • Power House 2 x 20 MW and Switchyard
Dam Fill: 4,950,000 m3
Total Earth moving: 9,012,000 m3
Concrete: 100,143 m3
Shuttering: 103,600 m2
Reinforcing-Steel: 7,306 t.
Grouting Works (Cement): 1,013 t
Rock Excavation for Dam Fill and Concrete: 471,000 m3
Drilling for Consolidation and Rock Excavation: 94,938 m




Last update: 24/09/2014