2015-09-09_PERMIT FILE - C1981019A (3)

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2010 Condition, partial watershed This condition is described on Figures Exh. 7 -PP -1 and Exh. 7 -PP -2. Subwatersheds A, B, C and R, three of which are immediately above Prospect Pond, are undisturbed, and will remain so for the entire duration of the plan described here. The reclaimed areas in subwatersheds L, M, N, Q2, Q1, X and Z are all in greater than 3 year vegetation, while the close -in subwatersheds D, E and F are in 1 -2 year vegetation. Further upstream watersheds K, Y, I and J are topsoiled and seeded. All of these reclaimed areas except L, which is already in greater than 3 years reclamation status, report through one or more of the stock tanks. The other subwatersheds are intercepted and re- directed to the East Pit. Overall, 550.7 acres are tributary to the sediment pond at this stage. Areas not tributary due to interception by the pit or the diversion ditches are called out on Figures Exh. 7 -14R -1 and Exh. 7 -14R -2 as "excluded." The SEDCAD modeling shows the runoff volume from the 10 year, 24 hour storm to be 4.74 acre feet, and the modeled outflow from Prospect Pond meets the settleable solids requirement. The pool in Prospect Pond does not reach the emergency spillway, and peaks about 1.77 feet below it. 2012 Condition, partial watershed This condition is described on Figures Exh. 7 -PP -3 and Exh. 7 -PP -4. Reclaimed areas in subwatersheds D, E and F are now been added to the greater than 3 year reclamation status, I, J and K have moved into the 1 -2 year status. Subwatershed H is now reporting, and is in 1 -2 year status. Subwatersheds O and P are also now reporting, and are in the topsoiled and seeded status. Four subwatersheds (W, U, T and V) remain intercepted by the pit and are not reporting. Overall, 625.7 acres are now tributary to the sediment pond, with the rest being intercepted directly by the active pit or by upstream diversion ditches. The SEDCAD modeling shows the runoff volume from the 10 year, 24 hour storm is 4.78 acre feet, and the modeled outflow from Prospect Pond meets the settleable solids requirement. The pool in Prospect Pond does not reach the emergency spillway, and peaks about 1.66 feet below it. 2017 Condition, Full Watershed This condition is described on Figures Exh. 7 -PP -5 and Exh. 7 -PP -6. All reclaimed areas are in greater than 3 year reclamation condition except subwatersheds U and V which are now at reclamation 1 -2 years, and subwatersheds S, T and W which are still in disturbed status. At this stage, all 711.1 acres of the watershed are now tributary to the sediment pond. This condition represents the worst case of the three 10 year, 24 hour models presented. Exh. 7 -PP -105 Revision Date: 12/10/12 Revision No. TR -97