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<br />Other floodplain concerns included stockpiling, the floodpath and flow velocities, how <br />much of the pits or lakes will be flooded, and how floodwaters will be safely routed back <br />to the main channel of the river. Concerns were also raised about the agricultural drain <br />tiles being affected, whether the headgate structures for the Jones Ditch and the Greeley <br />No. 3 Ditch will be affected, and how the riverbank and pitside banks will be protected <br />from excessive erosion. <br />All product stockpiles will be located within the processing area, in the fringe of the 100- <br />year floodplain. Overburden and topsoil stockpiles will not be located in the floodway, <br />unless they are down in the pits with the tops of the piles below the surrounding existing <br />ground surface or it is during the low flow season (October 1~` through March 3151). The <br />location, orientation, and configuration of all stockpiles is shown on the Weld County <br />Flood Hazazd Development Permit Map, included with this letter. <br />The 100-yeaz floodpath and flow velocities will not change significantly across the site <br />during the course of mining. The processing area and all stockpile locations have been <br />designed to minimize [heir effect on the conveyance of the river. Cells 1, 2, 3, 4, and 6 <br />will likely be flooded by a 100-year event. Backfilled dikes through some of the <br />reclaimed lakes will keep the floodplain from expanding beyond where is currently lies. <br />These dikes will be at or below the existing ground elevation. Spillways in the dikes will <br />be used [o equalize water surface elevations during a flood. Sufficient setbacks will be <br />provided along the river to protect from channel migration through the lakes. 'As the higY <br />water surface elevation recedes from a flood, water will naturally make its way back to <br />the main channel of the river. <br />The agricultural drain tiles will not be affected by any alterations to the floodplain. <br />Headgate structures for the Jones and Greeley Ditches aze off the main channel of the <br />river. Since there will be no activity that alters the capacity of the main channel, these <br />structures will not be affected. Again, pitside banks bordering the river will be protected <br />with minimum 200-foot setbacks. <br />If you have any questions on these responses, or need further clarification, please do not <br />hesitate to give me a call. Thanks. <br />Sincerely, <br />TUTTLE APPLEGATE, INC. <br /> <br />Dana Moore, EIT <br />Enclosure <br />File No. 99-182 <br />