Evaporation Loss
Reviewed • Standard Hydrology Definition • WaterLakeLevel
# Evaporation Loss
On large inland reservoirs, evaporation loss is often one of the largest single water consumers — sometimes exceeding all municipal and agricultural water withdrawals combined!
- High summer ambient air temperatures.
- Direct solar radiation warming the top epilimnion layer.
- Low relative humidity and dry winds sweeping across broad open-water fetch.
In arid southwestern reservoirs like Lake Mead and Lake Powell, evaporation can consume between 5 and 7 vertical feet of water depth every single year.
The invisible volumetric loss of water from a lake surface into the atmosphere caused by heat, sun, and dry winds.
The Hidden Impact of Evaporation
On large inland reservoirs, evaporation loss is often one of the largest single water consumers — sometimes exceeding all municipal and agricultural water withdrawals combined!
Why Evaporation Accelerates:
- High summer ambient air temperatures.
- Direct solar radiation warming the top epilimnion layer.
- Low relative humidity and dry winds sweeping across broad open-water fetch.
In arid southwestern reservoirs like Lake Mead and Lake Powell, evaporation can consume between 5 and 7 vertical feet of water depth every single year.
Explore Other Hydrology & Boating Terms
Acre-Foot
A volumetric water unit representing the amount of water required to cover one acre of land to a depth of one foot.
Conservation Pool
The volume of water stored in a reservoir dedicated to beneficial uses such as drinking water, power, and recreation.
Datum
A reference surface or mathematical baseline from which vertical elevations or geographic coordinates are reckoned.
Dead Pool
The critical low-water elevation below which water cannot flow downstream through gravity outlets.
Drawdown
The deliberate or natural reduction of a lake or reservoir water surface elevation.
Flood Pool
The temporary storage capacity above full conservation pool designed to capture floodwaters and prevent downstream damage.