Water cycle

• Antecedent moisture is the amount of water already present in the soil before a rainfall event.
• Percalines are lateral (sideways) lines of water seepage through the upper soil.
• Global processes that drive change in the hydrological system are:

  • Climate change.
  • Clouds and precipitation.
  • Cryospheric change.
• The water table is the upper level of an underground surface on which the soil or rocks are permanently saturated with water.
• Urbanisation affects water stores through:

  • Impermeable surfaces reduce infiltration and, therefore, groundwater storage.
  • The time that surface runoff reaches river channel stores etc. is increased.
  • Development impacts natural depression stores on the surface.
• Seawater ingress is the intrusion of seawater into freshwater aquifers, often caused by excessive groundwater extraction.