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United agrees to work with the CDPHE and notify them of the start of pumping, the location and <br />flow rates. If monitoring wells on the Fruita Marketing site show any problem with contaminant <br />movement, United will work with the CDPHE and the DMG to address the issue. <br />8. Hydrology and Sediment Control for Mining <br />No major streams or intermittent streams intersect the disturbed area although the Colorado River is <br />located approximately 330 feet to the south of the southern edge of the permit area at its closest <br />point. In between the permit area and the River is Interstate 70. Sediment control for the permit area <br />is provided by 4 items: <br />1) An earth berm will be placed on the existing terrain along the perimeter of the facilities area. All <br />runoff from the facilities area will be allowed to flow in the west ditch (existing along 15 Road) <br />which will flow south to the sediment pond. The berm around the facilities area will be a minimum <br />of 1.5 feet high with 2H:1V sideslopes. It will be constructed from topsoil excavated from the area <br />itself, <br />2) A small v-ditch of 1.5 feet depth around the south edge of the south topsoil stockpile, which will <br />also drain to the sediment pond, <br />3) A sediment pond of approximately 0.7 acres in size at the southwest edge of the permit area to <br />temporarily detain the water from pit pumping prior to discharge, utilizing a trapezoidal spillway of <br />10' width and 2:1 sideslopes. Riprap of 8"-12" will be placed in the spillway until the original drain- <br />age is met to ensure that no erosion occurs in the discharge structure. <br />4) pumping in the pit will utilize gravel berms around the inlet to provide filtering of sediment before <br />the water is pumped. <br />5) A diversion ditch of 2 feet depth, 2H:1V sideslopes and a bottom width of 4 feet will be installed <br />on the southeast portion of the permit area to keep undisturbed flows from entering the site. This <br />ditch will deliver the flows to an existing drainage culvert under I-70 as shown on Map C-2. No <br />ditch will be installed within the wetland marsh, which is a depressed area that will still drain to the <br />south. <br />The sediment pond is temporary until Area 1 is mined and the land peninsula is constmc[ed on the <br />west side from overburden from Area 2. Once this is done, the Area 1 lake will be allowed to fill and <br />will become one huge sediment pond. When this is done, it is not possible that the site will discharge <br />fora 100 year event in the upstream drainage area. The site is located partially within the 100 year <br />15 Road Pit 10/02 21 <br />