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• encountered in the six years of data, i[ can be calculated that s8.05 percent of [he 21.92 inches (12.72 <br />inches) of the maximum probable consumptive water use occurs prior to [he August to October tune period. <br />Upon ignoring such pragmatic consVain[s and using the most "worst case" assumptions possible, there is <br />still no measurable potential adverse impact of salinization of irrigated lands along Fish or Trout Creeks. <br />This is concluded from using the available site specific modeling techniques to predict irrigation water <br />quality impacts. TCC believes there is no available information to suggest [ha[ a potential for salinization <br />exists as a result of Foidel Creek mine discharge waters entering the current irrigation system. It appears <br />[hat dte components of [he current evaluation involving soil, w•a[er and plant salt tolerances have been <br />modified to meet all possible conditions for the "worst case" scenario. It is believed that the extent of <br />modification in the current analysis presents a scenario at least twofold worse than any expected probable <br />impacts could indicate. TCC requests that [he results of this study be accepted by the CMLRD to <br />document that there are no measurable impact to the essential hydrologic functions of potential <br />downstream alluvial valley floors. I[ is based upon the adoption of available scientific literature to the site <br />specific conditions of the Trout Creek drainage. <br />The water quality impacts for Fish and Trout Creeks, where measurable impacts have been projected and <br />evaluated in accordance with potential crop salt tolerance standards, no measurable impacts from applying <br />irrigation waters of elevated salinity values could be found. All currently available information suggests <br />there is no potential concern of the irrigated soils in the irrigated areas to become salinized. Potential <br />impacts of elevated salinity levels in Foidel Creek were evaluated and similar conclusions reached. No <br />agricultural diversion of Foidel Creek waters occurs until its confluence with Trout Creek. No measurable <br />water quality impacts for Middle Creek are projected and due to a prior negative determination in the <br />Foidel Creek Mine Findings Document (permit C-056-82) no additional evaluation of this drainage was <br />• performed. <br />The potential effects of mine water discharge on the waters suppl}'ing recharge to the alluvial deposits of <br />AVF areas in Foidel and Fish Creeks has been evaluated using salt loading projections during the period of <br />active alluvial recharge. Hydrographs of alluvial monitoring wells in Fish Creek and Foidel Creek <br />(Figures 4c, 4e, 4h, 4i) clearly show that recharge to alluvial aquifers occurs in response to increased flows <br />in [he adjacent creeks during the spring snowmelt period. Alluvial water levels decline rapidly as the <br />creek flows decline following the snowmelt period. This interpretation is significant as the water quality <br />of creek flows during the alluvial recharge period is not significantly affected by discharges of mine <br />inflows. <br />As discussed above, previously submitted data and supplemental data submitted in [Itis permit application <br />demonstrate that subirriRation is not an essential hydrologic function of two designated alluvial valley <br />floor areas. These areas are on Fish Creek near the Fish Creek fipple and at the Foidel Creek/Middle <br />Creek confluence area. The potential impacts of increased stream salinity on the associated alluvial <br />aquifers in these two areas is therefore not considered to be at issue. However, it should be noted that the <br />Itydrograplts for alluvial wells in these two areas support the interpretation of the recharge/discharge <br />characteristics of alluvial aquifers in this region which is discussed on page 2.04321 of the permit <br />application. Solute concentrations in these hvo alluvial wells (008-AV-2 in Figure 4h and 008-AU-3 in <br />Figure 4i) have not shown any evidence of increases above baseline levels during the past two years of <br />operations at the Foidel Creek Mine. <br />Salt loading evaluations have been presented in Table 64 that indicate that salinity threshold levels +vill not <br />. be exceeded in Trout Creek during low Flow periods as a result of mine discharges to Foidel Creek. <br />Recharge of alluvial deposits, which occurs primarily during the spring runoff period when water quality is <br />better than during low flow periods, is therefore no[ anticipated [o affect the subirrigation function of AVF <br />areas in the Trout Creek valley. <br />MR 97-1 ~4 ? 06-20 9/10/97 <br />