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o c"'.) W C") c.n ~ Records of monthly pan evaportation at stations in and surrounding the study area were tabulated. Seasonal May-October pan evaportation was adjusted to annual pan evaporation and a relationship' was developed of annual pan evaporation versus elevation. Annual pan evaporation at each reservoir site was determined using this relationship. Application of the appropriate pan factor resulted in estimates of gross lake evaporation. Net evaporation was computed by taking into account the precipitation salvaged due to the presence of the reservoir. The net evaporation was applied against the net surface area to yield the estimates of reservoir evaporation shown in Table 4. Municipal, Domestic, and Industrial Uses In order to estimate the municipal and domestic water uses of the Navajo Nation, use was made of the approach adopted for the Upper Colorado Region Comprehensive Framework Studies. The Indian population in the Arizona por- tion of the Upper Colorado River Basin in 1966 was 27,772. It was estimated that the per capita water consumption of the Indian population was 26.6 gallons per day. Applying this consumptive rate against the population figure resulted in a depletion of 833 acre-feet per year. The 1980 level of deple- tion was estimated at 1,611 acre-feet per year which is based on an estimated population of 39,300 and an assumed per capita consumptive use of 37 gallons per day. The town of Page pumps its water supply from Lake Powell at Glen Canyon Dam. The water is treated and t.hen metered to the residents. Effluent from the Page Sewage Treatment Plant i. discharged into lined stabilization ponds and allowed to evaporate. Watel' meter readings were supplied by the Page TOIm Manager. Water use values are shown in Table 1. i