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®~ur~J <br />-23- <br />Outside of the Big Bottom and Round Bottom ground water study areas high well <br />yields are obtained from the unconsolidated alluvial deposits of the Yampa <br />River and its tributaries. Well yields range from 5 gal/min to as much as 900 <br />gal/min in a well east of Craig, Colorado (Brogden and Giles, 1977). The <br />principal use of water from the alluvial aquifers is for domestic and stock <br />watering purposes, however, permeabilities are sufficient in some areas to <br />support long-term, high yield wells for municipal and industrial needs and <br />irrigation. The ground water level data for the Yampa and Williams Fork <br />alluvial wells were plotted on hydrographs (Figures III-17 and III-17k in the <br />Eagle No.S and No.9 Mines' permit application). The hydrograph for the <br />Williams fork alluvium shows seasonal fluctuations with high ground water <br />levels in the months of May to July during high river stage. <br />Water quality is variable, depending on the underlying rock and source of <br />alluvial material. Ground water from the Yampa River alluvium i.s primarily <br />sodium sulfate type. Dissolved solids average 4,586 mg/1 with a maximum <br />measure of 8,810 mg/l. Ground water for the Williams Fork alluvium is <br />primarily of the sodium bicarbonate type. Total dissolved solids average <br />1,009 milligrams per liter (mg/1) with a maximum measured value of 1,510 <br />mg/l. Maximum primary and secondary drinking water standards are exceeded in <br />both aquifers for many parameters including barium, cadmium, chloride, <br />chromium, pH, sulfate and selenium. In addition, average concentration values <br />for chloride, total dissolved solids, iron, lead, manganese and sulfate exceed <br />EPA primary and secondary standards. <br />There are six springs within the permit and adjacent areas of the Eagle <br />Mines. Empire Energy Corporation has provided data on four of these, the <br />north, east, south and No. 9 face-up. The north spring, also referred to as <br />the Lippard No. 2, originates at the head of a small drainage near its <br />function with old highway 13 along the base of a thin Pleistocene or <br />quaternary gravel that caps many terraces in the area. The east spring flows <br />from the base of a highway fill and appears to be a man made situation. <br />Approximately one mile south of the No. 5 mine portal the south spring is <br />located on a hillside west of the Williams Fork River. Water issues from a <br />sandstone lenses within the Iles Formation A small seep is found at the No. <br />9 mine face-up. This spring flows only in the spring and dries up in the <br />summer. In total, flow from the four springs is less than 20 gpm. The four <br />springs that were surveyed do not appear to be discharge zones for any of the <br />regional bedrock aquifers and are not considered significant. <br />In addition to the springs discussed above, a seep has been observed issuing <br />from the base of the old Williams Fork Strip Pit No. 1. Water percolates <br />through the regraded spoils of the Williams Fork Strip Pit No. 1 and drains <br />into the Williams Fork River. Mean flow is 58 gpm ranging from 4-198 gpm. <br />This appears to be created by old mining disturbances by filling a local <br />drainage with mine spoils. Discharges from the springs and strip pit have <br />relatively poor quality. A spoils aquifer is also anticipated to develop in <br />the backfilled Trapper Hine. <br />