Prediction of Class A Pan Evaporation in Southwest Idaho

Abstract

Class A pan evaporation from three sites on the Reynolds Creek Experimental Watershed in southwest Idaho showed that a single equation that incorporated solar radiation and mean temperature could be used to estimate daily pan evaporation. The estimates could be improved by adding a daily wind run term to the basic equation. Daily evaporation varied between 7.5 mm/day at the mid elevation site (1,649 m) and 6.5 mm/day at the highest elevation site (2,097 m). Daily amounts were very similar for the low elevation site (1,193 m) and the mid elevation site. Total summer evaporation was 1,255, 1,082, and 795 mm for the low, mid, and high elevation sites, respectively.