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Water from the mine will change the hydrographs of Foidel Creek and Fish Creek <br />by relocating the zone of discharge and by accelerating the ground water <br />discharge through the mine's dewatering activities. Mine inflow waters will <br />be discharged to Foidel Creek through the main portal north of Mine No. 1 and <br />to Fish Creek through the Fish Creek Borehole Shaft north of Mine No. 2. The <br />Foidel Creek portal area will maximally discharge 125 gpm (0.28 cfs) <br />throughout the first fifteen years of the life of mine and an average of 82 <br />gpm (0.18 cfs) thereafter. The Fish Creek Borehole Shaft will discharge a <br />maximum of 185 gpm (0.41 cfs) to Fish Creek and an average of 79 gpm (0.17 <br />cfs), throughout the life of mine. The Foidel Creek portal currently <br />discharges an average of 121 gpm (0.23 cfs) and has already transformed Foidel <br />Creek from an intermittent stream into a perennial stream. Fish Creek has <br />always been a perennial stream. <br />Changing an intermittent stream into a perennial stream can potentially alter <br />the geomorphic equilibrium of the receiving stream and cause the stream to <br />downcut. The applicant reports that the headwaters and upper reaches of <br />Foidel Creek in Eckman Park display an armored streambed. In the middle <br />reaches, stream gradients are reduced, and three narrow flood plains have <br />developed. The uppermost area is shown on Map 15, "Alluvial Valley Floors and <br />Water Rights". Mine water would be discharged to this area. The floodplain <br />of this upper area is truncated by bedrock outcrops as Foidel Creek outcrops <br />probably control the local base level of the stream. Downstream from the <br />watergap, a second floodplain has developed. The stream then flows through a <br />shallow canyon, where resistant sandstone outcrops have prevented lateral <br />migration of the stream. A third floodplain area is found on Foidel Creek <br />gust upstream of the confluence with Middle Creek. The applicant has <br />indicated that the stream channel in the floodplain areas is already naturally <br />incised as a result of recent downcutting. <br />In addition, the amount of water expected to be discharged on a continuous <br />basis to the channel would be relatively small. At a mine discharge rate of <br />125 gpm, the base flow in the stream would be only 0.28 cfs. In fact, this <br />discharge would be further reduced by infiltration through the streambed into <br />the alluvial aquifer system in certain stream segments. Therefore, because of <br />the relatively low discharges involved and the periodic bedrock control Of the <br />stream, mine water discharge is not expected to cause significant downcutting <br />along Foidel Creek. <br />Discharge from the Fish Creek Borehole shaft will move the ground water <br />recharge point approximately seven (7) miles upstream and increase it during <br />mining operations. The applicant estimates that the two aquifers affected by <br />dewatering, the Wadge overburden and Trout Creek sandstone, currently <br />-48- <br />