Sand Bypassing Methodology For Sustainable River Mouth Opening

River inlets along the Tamil Nadu coast remain mostly closed due to negligible fresh water flow and also due to various structures constructed near to the river inlet obstructing natural sediment transport. Excessive development of the sand spit also causes serious problems such as water level rise during floods and difficulty in navigation through river mouth. To reduce the impact of coastal area flooding and easy navigation it is necessary to keep the river mouth open. River training walls (RTW) are generally constructed to keep the river mouth open. Depending upon the sediment transport direction, sediments get deposited on one side of the RTW, while depleting the sediments from the other side. To prevent the sediment deposit from spilling over to river mouth, it is ideal to bypass the sand to the other side of the river mouth. This study analyses the methodologies for sand bypassing. A numerical model study has been carried out using DHI LITPACK to evaluate the sedimentation. The procedure of sand bypassing using pumps and pipe lines are discussed. Volume of sand bypassed, pump capacity, the number of Booster pumps to maintain critical velocity etc. can be determined based on the procedure discussed