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Pond embankments, slopes, spillways and construction methods have been designed <br />according to such engineering factors as structural integrity and stability, slope and surface <br />stability; adequacy in height, size and shape to provide sufficient volume for sediment and <br />detained water and selection of proper spillways and outlet devices, passing of design storm <br />events and proper outflow rates. All ponds have been designed under the direction of a <br />qualified, registered professional engineer. <br />The purpose of the sedimentation ponds is not only to provide a final measure to prevent <br />additional contributions of sediment outside the permit area, but also to provide a means of <br />compliance with all applicable effluent limitations, especially with respect to total suspended <br />solids or settleable solids, as required. <br />The effluent quality is regulated by Section 4.05.2 and by the National Pollutant Discharge <br />Elimination System (NPDES) Permit. The NPDES Permit was issued by the State of <br />Colorado Department of Health under the National Pollutant Discharge Elimination System, <br />established as a result of the Clean Water Act (33 U.S.C. Section 1251, et• sea•). A copy of <br />the approved NPDES Permit is found in Exhibit 7, Hydrology Information. <br />The engineering parameters for the various sedimentation ponds are inc]uded in Exhibit 7, <br />Hydrology Information. The engineering design parameters for the various diversion ditches <br />are also included in Exhibit 7, Hydrology Information. Cross sections for the sedimentation <br />ponds and the designs for the emergency and primary spillways are shown in Exhibit 7, <br />Hydrology Information. <br />With the construction of the Streeter Fill and the future development of the West Pit, the <br />original drainages have been relocated as shown on the Posi Mining Topography (Map l9). <br />The details of these permanent diversions are set forth in Exhibit 12, Experimental Practice <br />Information, and Exhibit 7, Hydrology Information. Note that for continuity the <br />"Experimental Practice" information in the permit is left intact to provide a historical record <br />of the Streeter Fill which is now an excess spoil fill built to meet the standards of Rule 4.09 <br /> <br />2.05-23 <br />