Evapotranspiration Parameters Research Articles

Calibrating the USDAHL Hydrologic Model on Grassland Watersheds

ABSTRACT THE USDAHL model was calibrated on a 6.3 ha grassland watershed using three different methods. The vegetative parameter, A, depression storage parameter, VD, evapotranspiration parameter, ET/EP, and groundwater recharge parameter, GR, were varied until each type of calibration was accomplished. Then to evaluate the types of calibration, the parameter values were transferred to a 7.8 ha grassland watershed without further manipulation. The Type II calibration proved best by predicting runoff with a 1.7 percent error on the second watershed. The Type II parameter values were A = 0.6, VD = 1.27 mm, ET/EP = 0.88 and GR = 0.0229 mm.