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<br /> TABLE 1 <br /> SPILLWAY RATING COEFFICIENTS <br />SpecifIC Discharge Approach Pier Abutment Contraction <br />Energy/ Coefficient Depth Contraction Coefficients. K . <br />Oesign Head C. AdJU8""ent Coeflicients . Concrete 11) Eerih (2) <br />HE/HO Exponent. E (31 K, <br />0 3.100 0 .123 -.008 .005 <br />.1 3.205 .0059 .101 .023 .030 <br />.2 3.320 .0090 .082 .045 .053 <br />.3 3.415 .0114 .063 .062 .074 <br />.4 3.520 .0135 .046 .074 .092 <br />.5 3.617 .0155 .034 .081 .112 <br />.6 3.710 .0174 .026 .089 .123 <br />.7 3.800 .0191 .017 .093 .137 <br />.8 3.880 .0208 .009 .097 .150 <br />.9 3.943 .0224 .003 .099 .162 <br />1.0 4.000 .0241 0 .100 .174 <br />1.1 4.045 .0260 -.006 _100 .182 <br />1.2 4.070 .0281 -.012 .100 .189 <br />1.3 4.090 .0307 -.013 .100 .194 <br />(1) Abutment contraction coefficients for adjacent concrete non~overflow section <br />Waterways Experiment Station (W.E.S.) Hydraulic Design Chart III - 3/1 dated <br />August 1960 and making KA = .1 and HE/HD = 1.0 <br />(2) Abutment contraction coefficients fo.' adjacent embankment non-overflow section <br />from W,E.S. Hydraulic Design Chart III ~ 3/2 Rev. January 1964. <br />(3) Pier contraction coefficients for type 3 piers are from PI&te 7 of <br />EM 1110.2.1603 (Corps of Engineers, 1965) <br /> <br />For a trapezoidal spillway, outflow is computed form critical depth and <br />the velocity head as: <br /> <br />hv = V2 = A <br />2g 2T <br /> <br />(13) <br /> <br />where: <br />h y = <br />V <br />g <br />A <br />T <br /> <br />velocity head in feet <br />= velocity in feet per second <br />= acceleration of gravity <br />= cross sectional area of flow <br />= top width at critical depth in feet <br /> <br />7-79 <br />