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SPILLWAY INLET POND 5 <br /> 2YR. W.S.E.L. 4802.50 <br /> 1ft+2yr. <br /> Spillway Elev. = WS.E.L. = 4803.25 ft <br /> Adjacent Stream Invert Elev. = 4798.22 <br /> Length of Riverside Berm= 2300.00 <br /> Spillway Length Calc. <br /> A p= Area of Pond= 542,074.38 ft2 <br /> 0.6*A/12,000 <br /> L,= Length of Spill. = = 27.10 ft <br /> Length of Inlet Spillway= 27 ft <br /> SPILLWAY OUTLET POND 5 <br /> 2YR. W S.E.L. 4800.91 <br /> 1ft+2yr. <br /> Spillway Elev. = WS.E.L. = 4801.91 ft <br /> Adjacent Stream Invert Elev. = 4796.00 <br /> Spillway Length Calc. <br /> A p= Area of Pond= 542,074.38 ft2 <br /> 0.6*A/12,000 <br /> L,= Length of Spill. = = 27.10 ft <br /> Length of Outlet Spillway= 27 ft <br /> For HEC-RAS cross section referencing, see the work map (A2) given in 6.4.7- <br /> A2 No Rise Certification Report. <br /> As an additional check to predict if the spillways are adequately sized to fill the <br /> mining cells before breaching the river embankment, a non-steady flow HEC- <br /> RAS model was developed utilizing the ground geometry developed in the NRCR <br /> for the proposed reclamation plan. The unsteady flow data for the HEC-RAS <br /> model was developed by taking hourly flow points from the 100 year HEC-HMS <br /> inflow hydrograph published in the Lower Big Thompson Watershed Phase 2 <br /> Hydrologic Evaluation conducted by Jacobs Engineering in 2015 (see Figure <br /> 6.4.7-1 Big Thompson River 100 yr Inflow Hydrograph.). The flow points were <br /> normalized to a maximum flow of 11,500 cfs —which is the current flow value for <br /> the effective FEMA map in the vicinity of the AAR site. <br /> Amen Aggregate Resource <br /> Specific Exhibits <br /> Page 39 of 84 <br />