Reservoirs

• Water abstraction from rivers and reservoirs


  some abstraction of river water has little effect on the river as the used water is cleaned and returned

  However some abstraction don't return the water, reducing downstream flow e.g irrigation
• Over-exploited rivers


  River Nile- longest in the world but is also in conflict over what countries has right for water abstraction, dam installation for flow control, electricity and providing water
• habitat change due to reservoirs


  Flooding the reservoir destroys the previous habitat but creates new and valuable, uncommon welands
• Wildlife barriers due to reservoirs


  Dams and reservoirs act as barriers to migratory species, prevents recolonisation
• river regime downstream of dams effect due to reservoirs


  Reservoir may be used to regulate river flow in times of shortages
• Sedimentation due to reservoirs


  Sediments carried to the reservoir will sit, when they should have flowed downstream and fertilised floodplains and built up river banks, coastlines and counteracted erosion
• Microclimates due to reservoirs


  The large body of water may change the local climate. Greater evaporation happens due to the increased volume of water, this may increase humidity, cloud cover and precipitation downwind of the reservoir