What is evapotranspiration?

Evapotranspiration is the sum of evaporation from the land surface plus transpiration from plants. Evaporation is the process by which water changes from a liquid to a gas or vapor. Evaporation is the primary pathway that water moves from the liquid state back into the water cycle as atmospheric water vapor. The transpiration aspect of evapotranspiration is essentially evaporation of water from plant leaves. Transpiration accounts for about 10 percent of the moisture in the atmosphere, with oceans, seas, and other bodies of water (lakes, rivers, streams) providing nearly 90 percent, and a tiny amount coming from sublimation (ice changing into water vapor without first becoming liquid).

Source: USGS

The map and graph below show amount of evapotranspiration over time for different vegetation communities within the Central Wasatch Mountains.