Department of Earth Sciences/Integrated Watershed Management - Network/

Learning Content

Water balance

The water balance portrays the hydrological cycle quantitatively:

The general water balance equation is:

P - R - G - E - T = DS

where:

P	precipitation [unit of heigt] or [unit of volume/unit of time]
R	runoff, [unit of height] or [unit of volume/unit of time] R = R_out - R_in R_{out = runoff as outflow from the water body/hydrologic regin}R_{in = runoff as inlfux into the water body/hydrologic region}
G	groundwater flow, [unit of height] of [unit of volume/unit of time] G = G_out - G_inG_out = groundwater as outflow from the water body/hydrologic region G_in = groundwater as influx into the water body/hydrologic region
E	evaporation, [unit of height] or [unit of volume/unit of time]
T	transpiration, [unit of height] or [unit of volume/unit of time]
DS	change in storage, [unit of height] or [unit of volume/unit of time]