Assessment and mitigation of Akagera river avulsion

The Rusumo Falls Hydroelectric Project (RFHP) is currently under construction. Upstream of the project site, shortly before the former confluence of the Nyabarongo and Akagera rivers, an avulsion has occurred and the Nyabarongo river is now flowing directly into Lake Rweru. If there are important changes in flow regime in the Akagera river, this may impact the planned energy generation at the RFHP. The project will therefore assess the impact of the Nyabarongo River avulsion, and, if required and necessary, develop cost-effective mitigation measures to ensure that the planned power production at the RFHP remains unaffected.                                                                                                                                                                                                                                                                                                                                                  .                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

                                                                                                                                                             .             

Actual services provided by our staff within the assignment:

  • Collection of existing datasets and field measurements
    • Topography of the marshlands
    • River bathymetry
    • Rweru lake bathymetry and set-up of lake level station
    • Water flow data incl. Acoustic Doppler Current Profiler measurements and installation of telemetry at flow gauge
    • Sediment data incl. sampling of bed and suspended sediment load
    • Evaporation / evapotranspiration data, precipitation incl. set-up of meteorological station
  • Review of existing information and reports on the Nyabarongo and Akagera Rivers
  • Water balance study including detailed hydrological and hydraulic modelling
  • Assess impact on RFHP power generation capacity
  • Identification of potential mitigation measures 

Name of client: Nile Equatorial Lakes Subsidiary Action Program (NELSAP)
Start date
(month/year): 08/2019
Completion date (month/year): 11/2020