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the longer period continuous discharge of snowmelt floods, and the <br />high peak flows and total shorter duration and volume of a rainfall <br />flood. These flood projections for the Henderson Mine and Mill are <br />listed in Table 6.3 in the Flood Study. Final flood contr~~l facili- <br />ties are discussed below by drainage basin. <br />1) West Fork of Clear Creek <br />Flood protection will not be a major concern for the West <br />Fork of Clear Creek since there are not major impoundments and the <br />mine-plant facilities are located at a point above the provable flood <br />plain. A 102-inch bypass pipeline has been constructed caF~able of <br />passing a flow in excess of a 100-year flood. <br />2) Williams Fork River <br />The west portal of the Henderson Tunnel is located near the <br />confluence of the Williams Fork River and the South Fork of` the <br />Williams Fork River. The surface railroad is constructed c>n a fill <br />which crosses the Wiliams Fork Valley at a grade of +18. There are <br />three culverts which pass underneath the fill at the Williams Fork <br />River and two culverts which pass underneath the fill at the South <br />Fork of the Williams Fork River. These culverts are sufficient to <br />pass a 200-year flood. There is also a twin multiplate arch underpass <br />constructed through the fill for the county road. This underpass <br />provides flood protection in addition to the culverts placed in the <br />streams. At the termination of mining activity, a portion of the <br />tunnel fill will be removed to allow for the required flood protection. <br />3) Ute Creek <br />The Henderson Mill and tailing deposition facilities are <br />located within the Ute Creek drainage basin separate from but <br />9-7 <br />