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<br />0019;)0 <br /> <br />Minina Depletions <br /> <br />Mineral mining water use occurs when water is diverted for extracting and milling of minerals. <br />Diversions to mines occur throughout the San Juan River Basin but most diversions to mines occur in <br />the Animas River, La Plata River and the Lower San Juan River drainages. The National Water-Use <br />data files indicate that most withdrawals to mines occur through pumpage of groundwater and only a <br />very small portion is from surface water diversions. Because it is unknown to what extent water <br />pumped comes from groundwater supplied through seepage of surface water, it was decided to use the <br />reported fresh water use as reported. <br /> <br />Annual mining depletions within the San Juan River Basin portion of the State of Colorado showed a <br />steady increase as reported in the USGS "Estimated Use of Water in the United States" reports. Of <br />this total, it was reported that only about 0.16 million gallons per day was depleted from fresh water <br />sources for year 1985 with a opposite trend. This equates to about 179 acre-feet per year of fresh <br />water depletions. Since data was lacking to adequately estimate depletions for years 1986 to 1993 and <br />the previous years showed a downward trend of fresh water depletions, it was decided to use a <br />conservative mining depletion of 150 acre-feet to represent mining depletions for the State of <br />Colorado for the period 1986 to 1993. Mining fresh water depletions in the State of Utah data <br />showed an opposite trend, which increased at a rate of 410 acre-feet per year. This trend was used to <br />establish the 1986 to 1993 annual mining depletions. <br /> <br />Estimates of mining depletions for the State of New Mexico were obtained from the New Mexico <br />State Engineers Office report on "Water Use by Categories in New Mexico Counties and River <br />Basin, and Irrigate Acreage" report for 1975, 1980, 1985 and 1990 published once every five-years. <br />Data from each five-year report was used to represent the preceding five years. Depletions for 1991 <br />to 1993 were based on the 1990 report. The State of Arizona mineral depletions were obtained from <br />the annual "Consumptive Uses and Losses, Arizona Portion of the Upper Colorado River Basin" <br />reports. All states mining annual deletions were evenly distributed by month. <br /> <br />Fish and Wildlife <br /> <br />Fish and Wildlife depletions represent all depletions associated with Fish and Wildlife recreation <br />including reservoir evaporation and irrigation of refuge wild feeding areas. Also included in this <br />category is depletions at national and state parks, golf courses and miscellaneous businesses dealing <br />with recreation. Colorado's data was provided by the CRSCU&L reports, while New Mexico's data <br />came from the Reconnaissance Study of Water Resources and Preliminary River Network Modeling, <br />Nonhwest Unit, New Mexico Water Resources Assessment, Technical Memorandum, December 1994. <br /> <br />Proportionina HUe Non-Irriaation Depletions to Gauaina Stations <br /> <br />As with irrigation diversions, a proportion of each HUC's non irrigation depletion was associated <br />with a subbasin/core station gage. In case of stock pond and livestock depletions, the proportions <br />were assigned equivalent irrigation depletion acres, For the other water uses. proportions were based <br />on knowledge of population locations and other factors. <br /> <br />DRAFT - SJRIP Hydrology Model Documentation <br />June 18, 1999 <br /> <br />27 <br />