The Hydraulic Analysis of Side-Channel Spillways as Reservoir Outlets

This paper presents a simple computer-based methodology for analyzing the hydraulics of side-channel spillways, and concentrates on the performance of the spillway when the overflow weir is subject to heavy submergence - as may be the case when passing extreme floods as stipulated by the Reservoirs Act 1975. Published data, which define the relationship between the degree of submergence of a weir and the reduction in the weir's coefficient of discharge, is used to match the water profile in the receiving channel with that of the induced distribution of flow over the weir. Results are compared with those obtained from scale physical models.