Revision Notes

Hydrological Cycle

The Hydrological (Water) Cycle is the moving around of water in the atmosphere, sea, and ground in a continuous cycle. The path that the water follows is shown below:

Clouds —–> Vegetation —–> Ground —–> Soil —–> Rock —–> Sea —–> Clouds

The following processes are involved in the hydrological cycle:

  • Precipitation – water in any form that comes from the clouds (e.g. – snow, rain, sleet, hail)
  • Interception – this is where plants, trees, or buildings collect the precipitation
  • Stem Flow – where the precipitation flows along the stems of a plant to the ground
  • Through Fall – where the precipitation is not intercepted but falls straight to the ground
  • Infiltration – where the water filters through the ground and the tiny pores in the soil
  • Percolation – where the water moves downwards through the soil
  • Over Land Flow – this happens when either the soil is impermeable or saturated and the water flows over the top of it
  • Ground Water Flow – this is the movement of water sideways through the soil
  • Underground Flow – slow movement of water through the ground
  • Transpiration – where the water goes up through the plants and is released into the air through the leaves
  • Evaporation – where the water is evaporated straight from the ground or from the sea
  • Evapo-transpiration – here, the water vapour consists of both evaporated and transpired water