Stilling Basins for Pipe Outlets Using Wedge-Shaped Splitter Block

A series of experimental runs on the performance of stilling basin models with different configurations in terms of shape, size, and location of appurtenances was carried out to develop an efficient and economical stilling basin for circular pipe outlets. Test results from the experimental studies conducted on the outlets of 7.5- and 10-cm diameter, with inflow Froude number ranging from 1.70 to 5.50, are reported. A performance criteria obtained from scour parameters are described to compare the performances of the different basin models tested with the same erodible bed and a constant run time. A wedge-shaped splitter block was found to be very effective in spreading the jet of water over the width of the stilling basin within a shorter length, and resulting in a better energy dissipation. A set of experiments was also carried out to obtain the suitable size and the location of the wedge-shaped splitter block. The new stilling basin model with a wedge-shaped splitter block along with an impact wall, an intermediate sill, and a rounded end sill compares well in terms of performance with the USBR impact type VI stilling basin and is 25% shorter in length.