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accumulated sediment found in the pond will be removed and placed in a stockpile for later use in reclamation if the sediment meets the appropriate topsoil criteria. Sedimentation pond and diversion ditch removal are discussed in Section 4.05. The location of the proposed sedimentation pond and diversion structures to be constructed within the permit area are shown on the Mine Facilities Map (Map 12). The Regional Hydrology Map (Map 6) shows the location of watershed boundaries from which, along with other sources, the design criteria were established. Generally, the pond and spillways were sized and placed according to such hydrological factors as required sediment storage volume, rate of flow, and volume of flow for the appropriate storm event. The pond, spillways, and construction methods have been designed according to such engineering factors as structural integrity and ability, slope and surface stability; adequacy in height, size, and shape to provide sufficient volume for sediment and detained water and selection of proper spillways and outlet devices, passing of design storm events and proper outflow rates. The pond has been designed under the direction of a qualified, registered professional engineer. The purpose of the sedimentation pond is not only to provide a final measure to prevent additional contributions of sediment outside the permit area, but also to provide a means of compliance with all applicable effluent limitations, especially with respect to total suspended solids. The effluent quality is regulated by Section 4.05.2, and by the National Pollutant Discharge Elimination System (NPDES) Permit. The NPDES Permit was issued by the State of Colorado, Department of Health under the National Pollutant Discharge Elimination System, established as a result of the Clean Water Act (33 U.S.C. Section 1251, et sec). A copy of the • request for an NPDES Permit is found in Exhibit 3, Permits for Mining. 2.05-18