Drainage Basins

open, local hydrological cycles- is the area surrounding the river

INPUTS: precipitation – includes all the ways moisture comes out of the atmosphere. precipitation is mainly rain, but it also includes other types like snow, hail, dew and frost.



  1. Interception: is when water lands on vegetation or other structures before it reaches the soil.
    1. Only temporary because water may evaporate – average of 30% rainfall event in leaves
  2. Vegetation storage: is water that’s been taken up by plants:
  3. Surface storage: Total volume of water held on the Earth’s surface in lakes, ponds and puddles.
  4. Soil storage: Amount of water stored in the soil
  5. Groundwater storage: is water stored in the ground, either in the soil or in rocks
    1. The water table is the top surface of the zone saturation – the zone of soil where all the pores in the soil or rock are full of water
  6. Channel storage: Water held in a river or stream channel



  1. Infiltration: water soaking into the soil.
  2. Overland flow:/surface run off Water flowing over the land as a whole surface or in little channels
    1. Precipitation>infiltration
  3. Through fall: is water dripping from one leaf, or plant part, to another.
  4. Stem flow: water running down a plant stem or tree trunk
  5. Through flow: water moving slowly downhill through soil layer via pipes created by earthworms
  6. Percolation: The process by which water moves downward in the soil, toward the water table
  7. Groundwater flow: water flowing slowly below the water table through permeable rock
    1. Highly permeable can have a faster groundwater flow- followed by percolation
  8. Base flow: is the groundwater flow that feeds into rivers through riverbanks and river beds.
  9. Inter flow: Water flowing downhill through permeable rock above the water table
  10. Channel flow: the water flowing in the river or stream itself – river discharge.



  1. Evaporation: water turning into water vapour
  2. Transpiration: is evaporation from within leaves – plants and trees take up water through their roots and transport it to their leaves where is evaporates into the atmosphere.
    1. PET: potential evapotranspiration – the amount of water that could be lost by evapotranspiration
    2. Actual evapotranspiration is what actually happens.
  3. Evapotranspiration: The combined amount of evaporation and transpiration
  4. River discharge

Water Balance: the balance between inputs and outputs

  • Wet: P>ET = water surplus. Ground stores fill with water = more surface runoff and discharge- field capacity met
  • Dry: P<ET= Ground stores are depleted, water is used but its not replaced by precipitation. At the end there’s a deficit of water in the ground. The ground stores recharged in the next wet season.
  • Soil Water Budget: The balance of soil water.

Water Budget: P= O + E +/- S

P – precipitation

O – total runoff (streamflow)

E – Evapotranspiration

S – storage

  • River regime: the variability in a rivers discharge throughout the cause of a year in response to precipitation, temperature, evaportranispiration and drainage basin characteristics

Almeria Drought Spain 2008– Excessive soil moisture deficit

Europe’s largest exporter of Strawberries

Soil care Project: cover crops, irrigation management

Soils are loamy with low organic matter and nutrients content and shallow depth