Drainage Basin = area of land drained by a river and its tributaries. They are separated from each other by high areas of land called Watersheds
Inputs – precipitation, solar energy for evaporation.
Outputs – evaporation and transpiration, runoff into the sea, percolation to underlying rock strata.
Stores – puddles, rivers, lakes, soil storage, on vegetation etc.
Transfers or Flows – infiltration, percolation, overland flow throughflow and groundwater flow.