water cycle inputs, outputs, flows and transfers defenitions

soil water storage

• store

• water held in the soil

vegetation storage

• store

• water held on the surface of vegetation such as the surface of leaves

transpiration

• output

• the loss of water from the surface of the leaves of vegetation. water is drawn up through the roots and through the plant and then released onto the leaf surface through tiny pores (stomata)

infiltration

• transfer

• the passage of water down into the soil through the soil pores. the rate at which water is absorbed into the soil depends on the type of soil. water soaks into clay soils slowly but into sandy soils quickly

throughfall/stemflow

• transfer

• water that falls from the surface of leaves and branches to the ground. water also runs down the stems of plants during and after rain to reach the ground

precipitation

• input

  • all forms of moisture that reach earth’s surface

groundwater flow

• transfer

• the deeper movement of water through the layers of rock towards the river

evaporation

• outputs

• the transformation of water droplets into vapour caused by the sun’s heat

channel storage

• store

• water held as a store in the river or stream

groundwater storage

• store

• water stored in rocks underground in permeable rock strata

surface runoff

• transfer

• water that flows over the surface to eventually reach the river. this is a fast process and occurs when the soil and rock below are saturated (or baked), or the precipitation is so intense that it cannot be absorbed quickly enough

channel flow

• transfer

• water moving in the river as it flows

throughflow

• transfer

• the movement of water downslope towards the river within the soil due to gravity

surface storage

• store

• any water stored on the surface of the ground in lakes, reservoirs, ponds, puddles

interception

• store

• the process whereby raindrops are prevented from reaching the surface of the soil by leaves, stems and branches

river runoff

• output

• water leaving the drainage basin system

percolation

• transfer

• water moving vertically through the rock (under the soil). some rocks allow water to drain freely through them (limestone) while others are more impermeable