Laserfiche WebLink
water-quality standards . Two additional ponds are planned for a <br /> total of five in series at the tunnel refuse disposal area site . <br /> (4) Water control structures <br /> The rock tunnel portal site is located <br /> immediately adjacent to the confluence of the south and north <br /> forks of Dutch Creek - both perennial streams . Galvanized <br /> corrugated steel culvert sections are installed in both drainages . <br /> The north fork of Dutch Creek is routed <br /> through a temporary 10-foot diameter culvert designed to convey <br /> the peak flow runoff from a 100-year, 24-hour storm event. This <br /> culvert is placed in a temporary fill area which is part of the <br /> rock tunnel yard areas and across which the main haul roads to <br /> the No . 1 and No . 3 mines are located. This culvert is classified <br /> as temporary because it will be removed at the cessation of <br /> mining activities unless approved for retention as part of the <br /> postmining land use plan. An arched multiplate-type culvert with <br /> a cross-sectional area of 158 square feet has been placed in the <br /> south fork of Dutch Creek to provide access to the rock disposal <br /> area . The culvert is designed to convey the peak flow runoff <br /> from a 100-year, 24-hour storm event . <br /> Both of the preceding culverts have been <br /> designed and constructed in accordance with U. S . Forest Service <br /> specifications as well as the Colorado Mined Land Reclamation <br /> Board and the Office of Surface Mining specifications . <br /> Three sediment ponds with a capacity totalling <br /> 10. 11 acre feet have been designed and constructed on the south <br />