Hydrology of Crater, East and Davis Lakes, Oregon by Kenneth N. Phillips
WATER LOSS FROM THE LAKE
Evaporation loss has not been measured. It is perhaps somewhat more than that for Crater Lake because East Lake is in ‘a zone of less precipitation and probably lower relative humidity. For this report the average annual evaporation is estimated as 28 inches, 6 inches less than the regional average for the 4,000-foot plateau in the general area. The annual excess of precipitation over evaporation on the two lake surfaces (7 in. in -depth, or 1,330 acre-ft) is only a small part of the total annual water budget for the entire caldera.
The estimated average annual evaporation loss of 28 inches is equivalent to a loss of 2,190 acre-feet from the lake’s average area of 940 acres.