Laserfiche WebLink
E <br />SURFACE WATER HYDROLOGY <br />The site drainage plan and descriptions for associated structures for the CEC <br />Keenesburg Mine site are referenced in Appendix K of the Permit. Historically, <br />and as part of the reclamation process, CEC continues to maintain the diversion <br />ditches, drainage ditches, and drainage swales along the roads, and around the north <br />and east sides of the Permit property. These features will serve to convey any <br />surface water runoff to Sediment Pond 2. The present drainage facilities, as well as <br />existing site topographic features, are shown on the Existing Surface Features and <br />Utilities Map (see page 87). Certain surface water control features have been <br />designated as permanent facilities (by Permit revision, and at the direction of <br />CDMG and others). These features will remain following the completion of all site <br />reclamation activities. The permanent facilities include: <br />• Sediment Pond #2 <br />• The East and the West Perimeter Ditches <br />• The Dugout Pond <br />The permanent drainage features are identified on the Reclamation Contour and <br />Drainage Plan Map (see page 88). <br />. With the exception of Sediment Pond 2 and the Dugout Pond, all previously <br />existing man-made temporary pond sites have been closed, and subsequently <br />deleted from the drainage control mapping and monitoring requirement. This <br />action is considered appropriate because: 1) the sedimentation infill of Sediment <br />Pond 2 has been virtually non-existent after more than fifteen years of continuous <br />use, 2) Sediment Pond 2 has not had significant amounts of water stored in it for <br />more than brief periods (except during the unusual and prolonged periods of excess <br />precipitation in 1995 and 1999), and 3) even considering those unusual events of <br />1995 and 1999, to date there has not been an observed discharge from Sediment <br />Pond 2. <br />In addition, CEC implemented a dewatering scheme for Sediment Pond 2 in 1997, <br />in conjunction with the preparation of a, "Spill Prevention, Control and <br />Countermeasures Plan" for the site. This Plan was last updated in 2003 but is <br />reviewed annually. According to the Plan and as conditions warrant, CEC <br />personnel will pump the excess storm water runoff accumulated in Sediment Pond 2 <br />back to the Dugout Pond which is located about 700 feet slightly upgradient and to <br />the south-southeast on the CEC property. The Dugout Pond has an available <br />storage capacity exceeding the total contributing runoff volume associated with a <br />100-year, 24-hour design storm event ("Technical Revision, Drainage Control Plan <br />AHR-2008 -41-