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Surface Water Effects <br />McClane Canyon is an ephemeral drainage which is normally dry. Flows that do <br />occur are in response to snowmelt or intense rainstorms, and are usually of short <br />duration. McClane Canyon drainage is tributary to East Salt Creek, which is an <br />intermittent tributary of the Colorado River. Water quality is typical of and climate, <br />ephemeral and intermittent systems located in marine deposited sedimentary land <br />forms. Dissolved constituents often reach very high levels following dry periods and <br />during the winter, when stream flows are made up almost entirely of recharge from <br />ground water and from stagnant or semi-stagnant pools. Suspended solids levels are <br />high during spring runoff and following high intensity rainstorms, due to sparse <br />vegetation and erodible soils. <br />Due to the limited areal extent of surface disturbance, existence of effective sediment <br />control measures, and small quantity and acceptable quality of projected minewater <br />discharge, operations at McClane Canyon have had little effect on the quality of <br />water in McClane Canyon drainage or East Salt Creek, and no significant effects are <br />expected. A full suite analysis of mine discharge water presented in Table 6 of the <br />2002 AHR shows a total dissolved solids (TDS) value of 1810 mg/l, compared to <br />TDS values of 3000 to 4000 mg/1 documented for East Salt Creek, at monitoring <br />sites SW-1 and SW-8, in Table 4 of the AHR. Following the conclusion of mining, <br />all culverts and diversions will be removed, and a network of ephemeral drainages in <br />geomorphic balance with adjacent areas will be reconstructed on the disturbed area. <br />Following successful vegetation establishment it is expected that surface water <br />hydrologic characteristics of the reclaimed area will approximate pre-mining <br />conditions. <br />In association with RN-06 and TR-15, the operator prepared a mass balance <br />evaluation to assess the effects of irrigation season mine water discharge on the <br />salinity (conductivity) of East Salt Creek water downstream from the point where <br />discharge water enters the stream. The evaluation included data from the 2001 <br />through 2005 irrigation seasons. During four of the five years, conductivity levels <br />were reduced due to dilution by lower conductivity mine discharge water. During <br />one of the 5 years (2005) there was a slight, but insignificant (0.2%; 0.004 mmho) <br />increase. Over the five year period, there was an over-all 10.9% reduction in <br />irrigation season conductivity on East Salt Creek downstream of the mine, resulting <br />from minewater discharge. These results confirm that mine discharge is not causing <br />a deleterious increase in stream salinity levels. <br />III. TOPSOIL <br />Soils resource information, including soil series descriptions, and evaluation of mine <br />bench materials for use as plant growth medium is provided in Section 4.4 of the permit <br />application. Information on topsoil management is provided in Sections 2.3 and 3.2, and <br />information on topsoil replacement is provided in Section 3.3. <br />No topsoil was stripped prior to mine bench and haul road construction, as this <br />disturbance occurred prior to the enactment of the Surface Mining Control and <br />21