In this paper the submerged flow through radial gates with and without a gate sill was experimentally investigated. The effect of different gate sill heights on contraction coefficient, discharge coefficient, submerged jump length, backup water depth, flow energy dissipation, and velocity distribution with different hydraulic parameters was analyzed and graphically presented. A combination of dimensional and regression analysis tools was employed to develop reliable formulas for estimating the studied parameters. This paper concluded the negative influence of sills under submerged radial gates and justified the local scour phenomena occurred immediately downstream the stilling basin of some existing submerged radial gates with a gate sill in Egypt.