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Mr. Gregg Squire • • Page 6 December 20, 2000 right-of--way which adds another twenty feet to the 2:1 setback. When the final letter is received from Questar, a copy will be forwarded to the Division's Denver office. Item 9 -Topsoil stockpiles in the floodplain. Any topsoil piles placed in the floodplain will be located so as to parallel the flow of the floodwater. Gaps will be left in long topsoil piles so that the length of the pile does not exceed 50 feet. The topsoil pile for the Dry Creek mining area has been moved toward the southeast corner of the pit to increase the distance from the river. Item ] 0 -Ponds in reclaimed pits. The reclamation plan assumes that the pits are reclaimed to the approximate original contour so that the ponds that form in the mined out pits will be contained in an incised pit. This reclatation concept provides for approximately four feet of freeboard from the assumed elevation of the lake and the top of the post mining surface. In a few cases additional fill has raised the ground 2-4 feet above the approximate original contour to fill in low spots to provide the required freeboard. These isolated fill depths above existing ground are less than the 10 feet height that requires the structure to be evaluated as a dam. While there is a nineteen foot drop in water surface elevation from east to west, Dry Creek and the ground elevation being above the 100 yr. floodplain provide a significant bamer to the eastern pits connecting to the West End Pit. Only the northwestern comer of the west pit area is in the 100 year floodplain so that if the bank was overtopped the pit would form a back water area. The pits in the eastern end of the project, the West Property Line to Horse Fence, Slough to East Property Line and the Dry Creek areas may possibly interconnect if the area is subject to a 100 year flood. The topographic mapping shows that this area is an historic overflow for the Colorado River if a 100 year flood occurs. The area is covered by 0.3 to 4 feet of water. The flood depth varies with the surface topography with the deeper sections being in the vicinity of the slough on the south end of the pits. This slough area is near the outer edge of the floodplain boundary. If the pits overtop it is likely that the greatly increased surface area of the pits when compared to the river channel will potentially lower the base flood elevation and slow the flood water velocity down. Cross sections are being prepared for the river channel and the project area to asses the potential of flood impacts and to estimate at what flow the Colorado River will overtop its banks. This data will be forwarded as soon as it is completed.