Existing Shaft Spillway Enhancement Based on Physical Modelling

Abstract

The paper is focused on application of physical and mathematical modelling for the design of measures which either increase the capacity of the spillway and following outlet structures or improve the stability of the hydraulic conditions during extreme flows. Two different shaft spillways on dams in Czech Republic are presented within the paper. Firstly there was an incomplete circular shaft spillway experiencing problems with pulsations in the flume and capacity. Secondly the paper presents results from 1:20 scale physical model of high circular shaft spillway with pro-vortex vanes dealing with capacity issues, insufficient aeration and pulsation in the tunnel during high flows.