The Zambezi River and the Victoria Falls. Image credit

ZIMSEC O Level Geography Notes: Natural Resources: Energy:The siting and production of hydro-electric power

Large perennial rivers

  • These are also important and necessary for establishing HEP stations.
  • These ensure a constant supply of a large volume of water required.
  • When the rivers are seasonal, expensive dam construction must be undertaken.
  • If gorges are absent along such rivers where more durable concrete walls have to be built, then earth or rock-fill walls must be constructed along wide sections of valleys.


  • Large HEP stations require a lot of space which will be flooded by a new lake being built.
  • Therefore, such schemes are built in remote areas of low population density or areas not settled at all.
  • This is done in order to avoid the expense of compensating people for flooded homes and other property or resettling them in new environments.
  • The Kainji scheme in central Nigeria was built in a densely settled area and resulted in the displacement of 44 000 people in surrounding villages and towns.
  • The Zambezi valley here had few Tonga and Nambia people who were displaced and their livelihood disturbed.
  • Wildlife was displaced and translocated to Hwange National Park in the now famous Noah Operation.

Besides the physical factors given above, economic considerations also come into play in developing hydro-electric power (HEP).

  • HEP plants are expensive to build and so capital must be available to fund the construction of the stations.
  • This can come from private companies or the government.
  • Another economic factor is demand.
  • The need to use HEP in a country must be large in-order to warrant the expenses of building HEP schemes.
  • A country that is rapidly industrializing and urbanizing demands more electrical energy and plants must be built or the energy has to be imported.

To access more topics go to the O Level Geography Notes page