Water & Carbon Pack 2

water cycle as a system (5)

• Stores - Ocean (97%), cryosphere (2%), groundwater and soil moisture (1%), terrestrial surface water (0.01%), less than 0.01% in atmosphere and biosphere.

• Closed system as energy enters and leaves from the sun and as reflected heat but matter doesn’t enter or leave

• Inputs - precipitation (snow, rain, sleet, hail)

• Stores within system - interception, vegetation, surface water stores, soil moisture store, channel store, groundwater store

• Outputs - evaporation, transpiration, river discharge, groundwater flow

After precipitation water either flows as (4)

• Overland flow

• Soil throughflow

• Groundwater flow

• River/stream

what is overland flow

Movement of a sheet of water over the land surface towards a surface water store. Happens after short duration, high intensity, low intensity or long duration rain

saturation excess overland flow

Following long duration rainfall. Soil becomes so saturated that saturation excess overland flow begins

Infiltration excess overland flow

Following high intensity rainfall. Rain doesn’t have a chance to infiltrate, flash-flooding can occur as the water runs straight off the ground. Occurs mostly in semi-arid regions of the world where ground has been hard baked.