Drainage Basin Stores

Drainage basin stores aresurface or underground repositories of significant quantities of water that may regulate the rate at which input feeds through to the output.

Drainage basin stores include:

• Lake storage: water can either travel overland or via the river channel or precipitation can fall directly into a lake where it will be stored. Some water is released via a small outlet from the lake and some can be evaporated into the atmosphere.

• Interception by vegetation: the leaves, stems and trunks of vegetation can act as a barrier to precipitation reaching the land’s surface and water can be stored temporarily on these growths. The more dense the vegetation the more likely that water won’t reach the ground, whereit will be stored before being evaporated into the atmosphere.

• Absorption by vegetation: vegetation can withdraw water from the soil, river channels or overland flow via their root systems. The largest proportion of a woodland’s composition is its store of water. This may eventually be returned to the atmosphere by transpiration.

• Groundwater: water is stored within permeable rock underground, entering either through gaps between the grains (porous sandstone) or down joints and cracks in the rock (pervious limestone).

• Soil storage: water is stored around and between soil particles in what is called the pedosphere, or soil layer.

• Channel storage: the volume of water contained within the banks of a river will operate as a water store between its initial input and ultimate output.