Discharge Correlations for Spillways with Radial Gates

Equations used at the Tennessee Valley Authority (TVA) to compute free and gated (orifice) discharges through spillways with radial gates are presented along with correlations based on TVA model test data for discharge coefficients and submergence factors. The correlations and data may be applicable for estimating discharges through gated spillways that are similar to those at TVA and for which specific model test data are unavailable. Included in this paper, perhaps for the first time in the literature, are correlations and data indicating for given gate opening the headwater at which flow begins the transition from free discharge to gated discharge, the variation in the orifice discharge coefficient as headwater rises above the transition point, and the effect of tailwater submergence on gated discharge