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Peabody does not anticipate any pit ptmgaage or other flora into the pond at <br />this time. <br />Spillwav (Pond 0081 <br />Sediment Pond 008 provides for a separate principal and emergency <br />spillways to safely discharge the runoff fran a 25-year, 24-hour storm. <br />The principal spillway orifice inlet will also be used as the noncloggirg <br />dewatering device and is located at an elevation higher than the maviimim <br />sediment storage wlutne. ate principal spillway orifice inlet is located <br />in a position on the anbattlanent so as to prevent short-circuiting as much <br />as possible. `IYte stage-discharge relationship of the emergency spillway <br />channel was calculated using SEDCAD+, as was the stage-discharge <br />relationship of the principal spillway orifice. To be wnservative, it <br />was assumed that there was no flow thtrough the principal spillway in <br />determining the stage height for the 25-year aryl 100-year storm events. <br />Table 7-6f-16 is a suimnary of the As-built spillway data. <br />• TABLE 7-6f-16 <br />As-Built <br />Spillway Data Simnnaty <br />art i mart Pond 008 <br />Principal Spillway: Type Perforated Riser Inlet <br /> (~) <br />Orifice Diameter 4.7-inch <br />Orifice Elevation. 7011.5 <br />Barrel Diameter . 24.000-inch <br />Riser Diameter 24-inch <br />Length of Barrel 120.00 ft <br />Vertical Head Drop 17.50 ft <br />Mantling Coef 0.025 <br />10-year, 24-hour <br />Peak Stage Elevation 7014.4 <br />Top of Riser Elevation 7015.0 <br />F]tiergency Spillway: Type Trapezoidal atarv~el <br />Bottom Width 18 ft <br />length 35 ft <br />Side Slopes 4h:ly <br />Outfall Slope 13~ <br />D 50 Size 0.50 ft <br />Inlet Elevation 7015.8 <br />25-year, 24-hour <br />Peak Elevation 7017.0 <br />7-6f-16 Revised 08/24/92 <br />