RIVER EXE

• How long is the river exe?

  82.7km
• River exe source?


  in the hills of Exmoor
• River Exe mouth?


  the sea at Exmouth
• Where is Exmouth?

  Devon- South Coast
• River Exe tributaries?

  Has an extensive network of tributariews
• What is a tributary?

  A stream that joins a main river channel at a confluence
• River Exe drainage density?

  high drainage density
• Define drainage density?

  The area of land that is drained by a river and tributaries ?
• River Exe Geology?

  estimated 84.4% of the catchment is underlain by impermeable rocks , mostly Devonian sandstone, which accounts for the extensive drainage network
• Explain the link between the geology and the drainage density?

  Impermeable rock and soils tend to have higher drainage density due to the lack of infiltration and percolation

  • this means that water enters a channel quickly , leading to an increase in discharge
• River Exe Water Balance Equation?

  Precipitation 1295mm = evaporation +/- soil water change 451mm + runoff 844mm
• the orographic effect is the effect of what?

  high ground
• why is rainfall high\?

  orographic effect
• what % of precipitation becomes runoff?

  65%- WAY ABOVE NORMAL
• What happens to the remaining 35% of precipitation that DOES NOT become runoff?

  infiltrates/ intercepted
• give one reason that makes hydrographs subdued?

  the rural nature of the lower catchment

  • 82% of catchment is either woodland or grassland#
• what percetnage of the river exe catchment is either woodland or grassland?

  82%
• Give 3 reasons that might make hydrographs flashy in this basin?

  1. impermeable geology
  2. deforestation
  3. limited interception - 65% runoff