Surface evaporation is measured weekly to twice weekly using an evaporation pan compatible with standard National Weather Service evaporation measurements. Measurements are made twice per week during hot periods because of high evaporation rate. The following data is collected: number of days between measurements, beginning and ending measurement period, current, minimum, and maximum water temperature; initial water level; final water level; rainfall since last evaporation measurement, and calculated evaporation (inches). Data collection is ongoing.