The High Grand Falls Dam


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The High Grand Falls Dam

The new High Grand Falls Dam which is approximately 115m high, creating a reservoir of 5.5 billion m3, has multiple objectives: advanced hydroelectricity, maintaining low-water levels, supporting recession agriculture, irrigation and flood protection.

Projet : 

The High Grand Falls dam is a project of the Ministry of Regional Development in Kenya, designed to respond to various needs:


  • The production of hydroelectricity, by creating a waterfall of approximately 100m, for an average river flow a little under 200m3/s; the chosen option was to take advantage of the reservoir to turbine when basic resources are less available: peak daily energy and energy available in the dry season, with an installed capacity of 500 MW
  • Irrigation of 40 000 hectares
  • Maintaining the Tana’s low-water levels, throughout the year, with the additional supply of large supplies of water in the case of prolonged dry spells, to assure the livelihoods of the delta populations


The project has just finished a series of successive dams on the river Tana, which is already largely exploited for hydroelectric production, but with small storage capacities. The final dam will be a RCC construction completed with earth wings. The gated spillway (15000 m3/s) was placed on the RCC dam. A fusible dike ( Hydroplus rises on a fusible embankment dike) guarantees the solidity of the main dam in case of a flood higher than the exceptional deca-millenium flood and has just improved the security of the construction from the perspective of hydrologic uncertainties.

The electricity production factory is at the foot of the dam. It is equipped with five Francis turbines (100MW each). The transmission line connects the station to the national network near Nairobi.

Mission : 

At the heart of the consortium, ISL was in charge of the design of the main constructions : the dam, the plant, and demodulation dam. ISL provided the followng services:

  • Dimensioning of the reservoir (hydrological model and multi-purpose rersevoir simulation, GesRes software)
  • Choosing the type of dam and associated constructions;
  • Defining the objectives of the hydroelectricity production (support and services during the dry season)
  • Choosing the type of plant and associated equipment;
  • Providing a detailed project plan for the dam and plant: foundations, civil engineering, mechanical and electrical equipment.
Le projet
Pays/région : 
Ministry Of Regional Development Authorities
Période : 
Partenaires : 
Egis (leader), Egis Kenya, SCP, CAS.