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• sufficient amounts of water to fulfill the consumptive use water demands required by each <br />of the tlifferent vegetation types. <br />Based on the vegetation types and the consumptive use rates described on Table 7-4 there <br />is approximately 1,299 acre feet of water evapotranspi red within the study area. <br />Evaporation from the ponds were not included in this total. Excess irrigation water flows <br />overland and contributes to the streamflow of Calamity and Tuttle Draws. The streamf low <br />from Calamity and Tuttle Draws in turn contributes to the flow of the San Miguel River two <br />and one half miles downstream of mining and the proposed mining disturbance. <br />The total volume of water that could be evapotrans Aired from the vegetation study is <br />assumed to be under ideal conditions. In reality the evapotranspiration rates are <br />slightly less. In many areas shallow soils and rock ledges restrict rooting depths and <br />inhibit maximum plant growth, thereby reducing ET rates. <br />Aquifer Characteristics of the Nucla and Nucla East Mining Areas. Eleven aquifer tests <br />have been conducted within the Nucla leasehold, the proposed Nucla East mining area and <br />• the immediate vicinity. A wide variety of aquifer testing and analysis techniques have <br />been employed because of the range of well yields and aquifer types. Aquifer testing <br />techniques include constant discharge tests (Theis, 1935; Neuman, 1975; and Cooper and <br />Jacob, 7946); slug injection and withdrawal tests (Cooper et al., 1967, and Papadopul os et <br />al., 1973); modified slug tests (McWhorter, 1982); and specific capacity tests. Analysis <br />techniques primarily involve matching the drawdown of recovery data plots against <br />theoretical type curves or tangent lines defining the slope of the data. With the <br />modified slug tests, data analyses included either type curve matching or analytical <br />solutions. <br />The results of the pumping or slug tests performed on each well are presented in is ble <br />7-S. Statistical summaries of each aquifer are contained on Table 7-6. The specific test <br />data and graphs for all aquifer tests conducted to date are presented in Appendix 7-2. <br />Data analysis problems were encountered with four of the aquifer tests. The modified slug <br />test data plots for Wells GW-N9 and GW-N15 did not match well with any of the theoretical <br />type curves. This is apparently a reflection of aquifer conditions (fracturing, recharge <br />boundaries or perched layers) causing violations of some of the more critical assumptions <br />inherent with the analysis technique. The data plots are presented; however, the <br />• analytical solution was employed in each case to calculate the transmi ssivity. The <br />7-21 Revised 04/11/88 <br />