Erosion and Sediment Pollution Control Program Manual.pdf

Check the capacity of the emergency spillway.
1. Tables 7.5, through 7.8 are recommended for determining emergency spillway capacity for grasslined
spillways. Spillways lined with rock will typically have less capacity for the same-sized
spillway.
TABLE 7.5 - GRASS-LINED EMERGENCY SPILLWAY CAPACITY IN CFS
(Side Slopes 1H:1V)
Head
Bottom Width
(ft)
(ft)
8 10 12 14 16 18 20 22 24 26 28 30
0.5 6 7 8 10 11 13 14 15 17 18 20 21
0.6 8 10 12 14 16 18 19 21 23 25 27 29
0.7 10 12 13 17 20 23 24 28 29 31 34 36
0.8 13 15 18 22 25 28 31 35 36 39 42 45
0.9 17 19 23 27 31 35 38 42 45 48 52 55
1.0 18 22 28 32 37 41 46 50 52 56 61 65
1.1 22 26 32 36 42 47 52 57 61 66 72 76
1.2 26 32 37 42 49 54 59 65 71 77 83 89
1.3 30 37 43 48 56 62 70 77 84 90 97 104
1.4 34 41 49 56 65 71 78 87 95 101 109 117
1.5 38 46 56 63 72 80 88 97 105 113 122 131
1.6 42 52 62 71 81 90 98 108 117 126 136 146
1.7 46 57 68 78 89 99 110 118 129 139 150 161
1.8 52 63 75 86 97 108 120 129 141 153 165 176
1.9 56 68 82 93 106 118 129 141 155 167 180 190
2.0 62 75 88 101 115 128 141 154 168 182 196 206
2.1 67 81 95 109 124 136 152 164 180 193 209 222
2.2 72 88 104 119 134 159 164 169 194 209 224 240
2.3 79 93 109 125 144 161 176 193 210 228 241 258
2.4 84 102 119 137 154 172 191 206 225 244 258 276
USDA NRCS Engineering Field Manual
363-2134-008 / March 31, 2012 / Page 196