Stabilization of Riverbanks Using Bamboo Logs: Is This an Ideal Solution for the Sundarbans, India?

Abstract

In the deltaic region of the Sundarbans, India, human settlements have traditionally relied on constructing embankments along riverbanks to prevent flooding in inhabited areas. These embankments often experience toe undercutting due to swirling currents, tidal surges, and strong winds, which eventually leads to their failure. To mitigate erosion, bamboo logs are commonly used to cover the embankment face, as bamboo is locally abundant and cost-effective. However, field investigations reveal that the use of bamboo logs for embankment stabilization has not been an effective solution in the Sundarbans. This study seeks to understand why bamboo logs fail to provide a long-term solution for stabilizing riverbanks in this region. The research focuses on analyzing the turbulent flow characteristics near the bamboo log and sediment bank interface. To explore this, laboratory flume experiments were conducted using jute sticks as a scaled representation of bamboo logs. Turbulent 3D velocity measurements were taken around the logs to better understand how bamboo influences the flow and affects the embankment. The findings indicate that while bamboo logs initially slow down erosion and provide some protection, they eventually separate from the bank face as erosion progresses. Each log creates a significant wake region, increasing turbulence and shear stresses, which, in turn, accelerates the erosion process more than in unprotected areas