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the species listed above is tall fescue. Stability and capacity for this grass type is <br />listed as B. As stated earlier, prior to a "good stand of grass," the Landstrand will <br />protect the channel during passage of the 100-year, 24-hour precipitation event. Peak <br />estimated stage elevation with the passage of the 100-year storm is 6875.6, this leaves <br />4.4 feet of freeboard to the top of embankment. Please refer to Addendums A, B, and C for <br />capacities of both spillways during passage of the 10, 25, end 100-year storm events. <br />Table 13-3-12 presents [he preliminary design details for the principal and emergency <br />spillway. <br />TABLE 13-3-12 <br />Preliminary Principal and Emergency Spillway Data Summary <br />Sediment Pond 005 <br />Principal Spillway: <br />Type Drop Inlet (CMP) <br />Inlet Elevation (estimate) 6872.1 <br />Length 120 feet <br />Diameter 24 inches (opening) <br />Slope 2 X <br />• 10-Yr, 24-Hr Peak Stage (estimate) 6873.0 <br />Emergency Spillway: <br />Type Trapezoidal Channel <br />Channel Protection Rack and geotextile <br />Bottom Width 15 feet <br />Minimum Depth (w/freeboard) 2 feet <br />Length 50 feet (embankment) <br />Side Slopes 3H:1v <br />Inlet Elevation (estimate) 6874.0 <br />100-year, 24-hour Peak Stage (estimate) 6875.6 <br />Summary <br />The capacity of Sedimentation Pond 005 will be attributed partially to the embankment and <br />partially Co the pond excavation. During passage of the 10-year, 24-hour storm the <br />spillway does not discharge sediment downstream nor is [here any flow through [he <br />emergency spillway- The pond wilt eventually be a permanent impoundment structure, and <br />therefore has been designed to safely pass the flow from the 100-yea r, 24-hour <br />• precipitation even[. The final ponding capacity will be Constructed to contain <br />approximately three years of sediment storage. In addition, the spillway is designed and <br />13-3-13 Revised 03/13/92 <br />