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<br />0019j3 <br /> <br />FWS minus the greater of historical precipitation or salvage value. The salvage value is assumed to <br />be equal to the pre-reservoir losses. The salvage value, surface acres and fullness factors were taken <br />from the 1981-85 Consumptive Uses and Losses Report. <br /> <br />Stock pond evaporation values for the State of Arizona portion was taken from the annual <br />Consumptive Uses and Losses in the Arizona Portion of the Upper Colorado River Basin reports, The <br />State of New Mexico State stock pond evaporation numbers were supplied by the New Mexico State <br />Engineers Office. <br /> <br />Livestock Depletions <br /> <br />Livestock water consumptive use is the daily amount of water consumed by an animal. Incidental <br />uses or waste are not taken into account. In Colorado, livestock consumptive use was estimated by <br />multiplying the number of animals in each reporting area by the average use rate in gallons/headlday <br />(gphpd) taken from the Midwest Plan Service Structures and Environmental Handbook, 1977. The <br />reporting areas are the same as those used for stock ponds. For this report, the following rates were <br />used: <br /> <br />Livestock type Use in ~allons per day <br />Cattle 10 <br />Sheep 2 <br />Swine 3 <br /> <br />The number of animals is reported on a per county basis as part of the state agricultural statistics. <br />For counties which do not fall entirely within the San Juan River basin. the ratio of the GIS county <br />irrigated crop acreage to the County Agricultural Statistics, county irrigated crop acreage was <br />computed. This ratio was multiplied by the county total livestock data to estimate the portion of the <br />county livestock within the San Juan basin. County livestock numbers were aggregated into Hue's. <br />Arizona livestock consumptive use was taken from the annual Consumptive Uses and Losses in the <br />Arizona Portion of the Upper Colorado River Basin reports. New Mexico were supplied by the State <br />of New Mexico. <br /> <br />Small Reservoir Evaporation <br /> <br />A comprehensive listing was developed of all reservoirs in the San Juan River Basin which included <br />the latitude, longitude, elevation, and surface area at total capacity for each reservoir. <br /> <br />Monthly content records were obtained for those reservoirs for which records are available. The <br />average annual water-surface area was determined for each year of the reporting period. For those <br />reservoirs lacking records, a "fullness factor" was estimated on the basis of reservoir use and <br />historical hydrologic conditions. These "fullness factors" were then used to obtain estimates of <br />average annual water surface area for the unreported reservoirs. For all of the basin, annual free <br />water surface (FWS) evaporation rates were used to determine reservoir evaporation. <br /> <br />The FWS evaporation value was taken from NOAA Technical Report NWS 33, Evaporation Atlas for <br />the Contiguous 48 United States, June 1982, Map 3 of 4: Annual FWS Evaporation, based on the <br />reservoir location information. These values were used because of unavailability of pan evaporation <br /> <br />DRAFT - SJRIP Hydrology Model Documentation <br />June 18, 1999 <br /> <br />24 <br />