Drawdown (hydrology)

In water-related science and engineering there are two similar but distinct definitions in use for drawdown.

• In subsurface hydrogeology, drawdown is the change in hydraulic head observed at a well in an aquifer, typically due to pumping a well as part of an aquifer test or well test.

• In surface water hydrology and civil engineering, drawdown refers to the lowering of the water level in a man-made reservoir or tank.

In either case, drawdown is the change in head or water level relative to background condition, indicating the difference in head which has occurred at a given location relative to an initial time at the same location.

A record of hydraulic head through time is more generally called a hydrograph (in both groundwater and surface water).

Effects

Aquifer drawdown or overdrafting and the pumping of fossil water may be a contributing factor to sea-level rise.

Related

Subsidence