Evapotranspiration from Heterogeneous Mountain Meadows

The evapotranspiration rates of irrigated mountain meadow grasses were measured using non-weighing lysimeters during the 1979 and 1980 growing seasons. The lysimeters were located in a line across the Little Laramie River Valley near Laramie, Wyoming. The 1967 version of the Blaney-Criddle method for estimating evapotranspiration was calibrated using the lysimeter data (USDA, SCS, 1967).

Lysimeters 1, 2, 3, 8, and 9 were located in areas that were not irrigated. However, the Et rates measured by lysimeters 2, 3, and 9 were as great as Et rates measured by lysimeters in the irrigated portion of the mountain meadows. The high water table in these non-irrigated areas provided an extra source of water. The return flows from irrigated areas appeared to provide the bulk of the ground water.