2013-09-26_PERMIT FILE - C2009087

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Introduction The Upper and Lower Sumps were created to control runoff and sediment loads from the South Surface Facilities Area. The Upper Sump is located in the NE /4 of the NE /4 of Section 3, Township 5N, Range 87W, and the Lower Sump is in the NE /4 of the SE /4 of Section 34, Township 6N, Range 87W. The Upper Sump was constructed directly downstream of the PECOCO Pond and receives water from the upper coal pile as well. This sump will help collect coal fines from the area and allow them to settle out. The Lower Sump was constructed north of the Portal area and receives water from the two Portal Sumps. Water is pumped from the sumps and flows through Channel FA -D8 to the Lower Sump. Water from the Lower Sump then flows into Pond 002. As -Built Configuration Both sumps were constructed using an earthen embankment. The as -built configuration is shown on Map 2.05.3 -E2.E, Upper and Lower Sump As- Builts. The top width of the embankment of the Upper Sump is approximately 9' feet wide on average with upstream and downstream slopes of approximately 3H: 1V. The primary spillway is a 24 -inch diameter metal riser pipe. The emergency spillway is a trapezoidal open channel with a bottom width of 15 feet. The channel is vegetated and rip- rapped for added protection. The storage capacity is 6.44 acre -feet at the Principal Spillway. The Lower Sump's top of embankment width is approximately 11 feet with upstream and downstream slopes of 1 H: 2.5 V. The primary spillway for the Lower Sump is a 36 -inch diameter metal riser pipe with a trash rack mounted on top. The emergency spillway is a trapezoidal, open channel with a bottom width of 18 feet. The channel is vegetated and rip- rapped. The storage capacity is 7.51 acre -feet at the Principal Spillway. Compaction tests were also performed to ensure proper compaction of the embankment by Northwest Colorado Consultants, Inc. (NWCC). The results were found to be satisfactory.