Flow control by pile-group groynes used for riverbank instability management

Abstract

Smooth reduction of velocity from the mainstream to the bank is a desirable attempt when using a groyne for riverbank protection purpose. This can be achieved by applying modifications to groyne permeability or layout. In this study, the effects of different pile-group groynes on the flow deceleration were investigated experimentally. Different aspects including pile density, arrangement, row spacing and effects on the long downstream were considered. The results show that the pile arrangement pattern is an important factor on the control of flow magnitude and pattern behind a pile-group groyne. A gradual and smooth velocity reduction from the mainstream to the bank can be obtained by changing the arrangement of piles in a pile-group groyne.