Hydrology of Crater, East and Davis Lakes, Oregon by Kenneth N. Phillips
LIMITS OF ACCURACY
Davis Lake lies in a geographic belt where the precipitation decreases very rapidly from west to east. The average annual precipitation of 36 inches, estimated on the basis of records at nearby Odell Lake and Wickiup Dam, may be in error as much as 25 percent; it represents a small part of the total water supply reaching the lake. Average annual inflow of 150 cfs was estimated on the basis of records upstream on Odell Creek near Crescent in the period 1933-62 and gagings downstream on Davis Creek over a period of 24 years; it may be in error by 15 percent. Average annual evaporation loss of 30 inches was estimated on -the basis of records in the period May to September at Wickiup Dam; it probably is accurate within about 10 percent, and over a period of years will almost exactly offset the precipitation, most of which falls in the winter period, before the lake rises to the high summer stages that present a large area for evaporation. The average seepage of 150 cfs is estimated as equal to the average inflow, and that estimate is subject to the same possible error of 15 percent.