River discharge & hydrographs

Definition: The volume of water passing a given point at a given time, measured in cumecs
1. Velocity x cross-sectional area
Temperature
1. in low temperatures the ground freezes resulting in less infiltration and more surface run off
2. in high temperatures there is more evapo-transpiration reducing river discharge
Size, shape and relief of a river basin
1. Big river basin takes longer to get to the main river channel so there is less river discharge
  1. Smaller means less time and more discharge
2. Circular - gets to the river quicker
  1. Elongated - longer to get to the river
3. Steep slope means water travels quicker
  1. Gentle slope means more infiltration
Rock Type
1. Permeable (sandstone, chalk) allows pore to be filled = less discharge
2. Impermeable means increased surface run off
Soil Type
1. Space between soil particles
2. Soil moisture storage
Precipitation
1. More = saturation = high surface run off
2. High intensity - rain drops splash
3. Snow stored on ground then melts
Land Use
1. More trees = more interception
2. Urbanisation = nothing to intercept. concrete is impermeable
Hydrographs
1. Flashy
  1. Short lag time
  2. High peak discharge
2. Subdued
  1. Long lag time
  2. Low peak discharge
3. Discharge against time

Zusammenfassung der Ressource

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