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Show PART IV METHODOLOGY AND ASSUMPTIONS Type of System Municipal Rural-Domestic 1965 Population Served 101,225 35,500 136,725 Domestic Withdrawal Use Rate (gpcd 170 60 Total Use (mgd) 17.208 2.130 19.338 1965 household withdrawal coefficient = 19.338 mgd = 141 gpcd or 136,725 51,465 gpcy. Household sector withdrawal coefficients for the San Juan-Colorado Subregion were determined by a similar procedure as the weighted average of the municipal-domestic, rural-domestic, and Indian water-use rate. Assumptions given in the above procedure resulted in the subregional household sector coefficients shown in Table 33. Coefficients in the Green River and Upper Main Stem Subregions decrease with time because future wastes are minimized. Table 33 - Projected Withdrawal Rates for the Household Sector (gpcd) Subregion 1965 1980 2000 2020 Green River Upper Main Stem San Juan-Colorado 165 154 143 132 141 132 122 113 85 92 103 110 The 1965 depletion water-use coefficients for the household sector were estimated to be about 35 percent of the withdrawals. In the future target years, the depletion coefficients for the household sector were estimated to b 40, 40 and 50 of the withdrawal coefficients for the Green River, Upper Main Stem and San Juan-Colorado Subregions, respectively, Water requirements of the livestock sector include water evaporated from stock, ponds and water consumed by the animals. Livestock withdrawal requirements were assumed to equal livestock depletion requirements. The average annual net loss from farm ponds due to evaporation was obtained by multiplying the estimated net surface area of livestock water ponds by an average net evaporation rate for each subregion and state. The net evapo- 52 |