Reclamation Information Sharing Environment (RISE)

This is continued monitoring at Lake Powell Reservoir using the Collison Floating Evaporation Pan (CFEP) that came from S&T 8119. The CFEP has the following two important improvements over land-based Class A Evaporation Pans: (1) the temperature of the water within the CFEP is nearly identical to the water temperature of the surrounding body of water; and (2) the atmospheric boundary layer over the CFEP is nearly identical to the boundary layer over the surrounding body of water. Establishing these two conditions provided a significantly more accurate estimation of reservoir evaporation. In addition, the CFEP has three major improvements over floating and/or fixed tower open-water evaporation estimation methods (such as Eddy Covariance and Bowen Ratio Energy Balance and Mass Transfer equations) that are as follows: (1) the CFEP does not require a fetch distance, allowing it to be placed in fetch-limited locations; (2) the CFEP is considerably cheaper to build, maintain, and operate; and (3) processing of CFEP-collected data is considerably simpler.