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• The probable hydrologic consequences of mine related discharges on the water <br />quality in the confluence area of Foidel, Middle and Trout Creeks have been <br />analyzed. <br />1. Evaluation of the potential effects of the mine discharges on water <br />quality in the alluvium at the confluence area. This is required <br />because the CLMRD claims the area is sub irrigated alluvial valley <br />floor (AVF). <br />2. Evaluation of the effects of the mine discharges on the water <br />quality on the segment of Middle Creek in the confluence area during <br />irrigation season. This work is required because the CLMRD <br />considers the area to be potentially irrigatable AVF. <br />3. Evaluate the effect of the mine discharges on the water quality of <br />Trout Creek in the confluence area during irrigation season. This <br />work is required because the Trout Creek water is used for <br />irrigation purposes. <br />• The maximum impact from the mine discharges on the water quality of the <br />alluvium at the confluence area is estimated to be a 12% increase in dissolved <br />solids (see Exhibit A). This would occur during extremely low flow years. <br />During normal years, the maximum impact is estimated to be a 6% decrease. <br />These numbers are based upon an average dissolved solids concentration in well <br />08-AV-2, the stream flow data for USGS station 09243700 (3700) on Middle <br />Creek, and flow estimates presented to the CLMRD for the spoil springs. <br />The maximum impact of the mine discharges on the irrigation water quality for <br />waters from Middle Creek in the confluence area is to increase the dissolved <br />solids concentration to approximately the range of 1740 to 2242 mg/1 <br />(Exhibit B). This analysis is based upon water quality and flow data for <br />station 29 and spoil spring flow estimates. In addition, the minimum area to <br />be irrigated was assumed to be 20 acres from which a minimum pre-mining stream <br />flow required for irrigation was calculated. <br />This analysis is probably a moot point. This area of Middle Creek does not <br />appear to be economically feasible to irrigate with water from Middle Creek. <br />• The first place that a ditch could be taken out from Middle Creek below the <br />1 <br />Revised 10 1/86 <br />