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<br />~. TABLE 1 <br />GULCH A POND DATA <br /> 1981 Prmit 1981 Response 1985 Technical <br /> Application Volume 8 Revision <br />Watershed Area: ~ <br />Pre-Mini;ig 419 ac. 419 ac. 419 ac. <br />Post-Mining Disturbed 650 ac. 650 ac. 650 ac. <br />"Post-Mining-undisturbed 17 ac. 17 ac. 17 ac. <br />Post-Mining Total 667 ac. 667 ac. 667 ac. <br />Precipitation (10 Yr. 24 Hr.) 1.8 in. 1.8 in. 1.8 in. <br />Runoff Cid 67 67 67 <br />10 Yr. Runoff Depth .055 in. .055 in. .055 in. <br />10 Yr. Runoff Volume 3.06 ac. ft. 3.06 ac. ft. 3.Ob ac. ft. <br />3 Yr. Sediment Yield 0.58 ac. ft. 1.17 ac. ft. 1.17 ac. ft. <br />3 Yr. Sediment artd 10 Yr. Runoff 3.64 ac. ft. 4.23 ac. ft. 4.23 ac. ft. <br />Volume Below Emergency Spillway 5.01 ac. ft. 5.01 ac. ft. 5.01 ac. ft. <br />Volume Below Principal Spillway 1.26 ac. ft. 3.76 ac. ft.(a) <br />Elevations: <br />• Invert 6611 6'iL 6613.8 <br />Principal Spillway 6614 5~_5 6619 <br />Emergency Spillway 6620 - 6620 6620 <br />Top of Dam 6622 622 6622 <br />Bottom of Dam ~' 6611 6611 6611 <br />Principal Spillway: <br />Type 12" CMP 12" Ct•1P 12" CMP <br />Entrance Restriction 4" cap 4" cap 4" cap <br />10 Yr. r;atar Surface Elevation 6617.9 6617.9 6618.6 (b) <br />10 Yr. flood Detention Time 23.0 23.0 Contained <br />Emergency Spillway: <br />25 Yr. Runoff Volume 11.1 ac. f t. 11.1 ac. f t. 11.1 ac. ft. <br />Spillway Outflow 25 cfs 25 cfs 25 cfs (c) <br />Width 15 ft. 15 ft. 15 ft. <br />25 Yr. Water Surface Elevation 6620.42 6620.42 6620.42 <br />(a) Provides for containment of 10 Yr. <br />(b) Includes 60a 3 Yr. sediment. <br />(c) Note that peak floor is estimated at <br />24 Hr. event and 60% 3 Yr. sediment. <br />24.03 cfs. <br />