Water Balance

• What does the water balance show?

  The balance between inputs and outputs
• What is water balance worked out from?

  Inputs (precipitation) and outputs (channel discharge and evapotranspiration)
• What does the water balance affect?


  How much water is stored in the basin
• What does the general water balance in the UK show?


  seasonal patterns
• What happens in wet seasons?

  precipitation exceeds evapotranspiration

  this creates water surplus

  ground stores fill with water so there is more surface runoff and higher discharge, so river levels rise
• what happens in drier seasons?

  Precipitation is lower than evapotranspiration. Ground stores are depleted so some water used and some flows into the river channel but is not replaced by precipitation
• What is there at the end of a dry season?


  a deficit of water in the ground

  The ground stores are recharged in the next wet season ie autumn
• what is a deficit of water?


  shortage