Project Description

This project aims to monitor resevoir evaporation with a weather station buoy on Boca reservoir, CA, tributary to the Truckee River (Figure 1). Boca reservoir is a optimal water body to apply the aerodynamic-mass transfer approach because both water budget and energy budget estimates of evaporation can be easily estimated due to measured inflows, outflows, changes in storage, and water temperatures. In addition, evaporation from Boca reservoir is of great interest to the USBR and Federal Water Master for Truckee River operations. The buoy weather station will measure all required weather variables to estimate evaporation using the aerodynamic-mass transfer approach, while transferring these data in real time to Federal Water Master and USBR offices. The weather station buoy will also be equiped with a net radiaometer and thermal profile string to estimate evaporation via the Bowen ratio energy balance. Seasonal and annual estimates of evaporation using the aerodynamic-mass transfer and Bowen ratio energy balance will then be compared to water budget estiamtes of evaporation. Given that there is no method to ?measure? evaporation from open water, like a lysimiter for measuring evapotranspiration, an analysis of the strengths and weeknesses of each approach will be discussed in terms of their pratical application potential on a daily, seasonal, and annual basis.