Experiments on stilling basins for dam outlets

Abstract

A series of experiments was performed with the aim of developing shorter and more efficient stilling basins for dam outlets (in comparison with Garde's stilling basin), keeping the floor of the basin at the invert level (lowest level of outlet) of the outlet. The experiments were conducted for a pipe outlet diameter d = 58 mm, inflow Froude number Fr = 3·44 and basin lengths of 12d, 10d, 8d and 7d. New models were developed by conducting systematic experimentation on stilling basin models using different types of appurtenances such as wedge-shaped blocks, a grid, an intermediate sill and an end step. It was found that the newly developed stilling basin models are not only shorter in length but also show superior performance in terms of maximum depth of scour and its location when compared to Garde's model.