Kariba dam wall. Image credit Bloomberg.com

ZIMSEC O Level Geography Notes: Natural Resources: Energy:The siting and production of HEP 

  • Site refers to the actual ground on which something is happening.
  • The siting of a hydro-electric power station depends on a number of physical factors.

Gorge

  • A gorge is a deep narrow river channel or river valley.
  • Siting an HEP station here has the following advantages.
  • Much water is stored in a deep narrow valley.
  • Evaporation losses are minimized in such a valley.
  • Water flow is constricted and is fast and powerful to turn turbines.
  • The narrow valley reduces construction costs as not much concrete, cement and steel will be used.
  • Through vertical erosion, hard rocks are exposed in the valley with the advantages that a firm dam wall foundation is created and water loss through seepage is reduced.
  • For these reasons, HEP stations have been built at Kariba gorge in Zimbabwe, Cabora Bassa gorge in Mozambique among others increasing discharge and deepening the valley.
  • A waterfall which is near a near-vertical drop in gradient along river course is ideal for HEP stations because a large head of water is naturally created.
  • Turbines and generators are simply installed at the base of the waterfall.
  • Examples include Victoria Falls on the Zambian side, the Nkula Falls HEP station in Malawi on the Shire river, the Owen Falls station in Uganda on the Nile river among others.

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