Experimental Investigation on the Overflow Protection of Earthen embankment through vegetation

Abstract — Bank erosion is the worst calamities that adversely affect the economy by reducing agricultural land, houses etc. Bangladesh with its repeated cycles of flood, cyclones and storm surges has proved one of the most disaster-prone areas of the world where river bank, coastal erosion and embankment failure happen continuously. Resistance of vegetation may have a considerable effect in controlling flow velocity that makes overtopping erosion. Now-a-days vetiver grass is well-known as bioengineering and establishment of this technique to rigid or hard structures accepted all over the world for ri verbank stabilization and embankment erosion control due to its low cost and longevity. Therefore, to minimize the impact of natural disasters and to achieve the aim of agricultural production, sustainable and cost-effective maintenance of those embankments is prerequisi te for Bangladesh. In this study, it was aimed to investigate the effects of different vegetation density for controlling flow velocity during overtopping flow and their related hydraulic characteristics. Experimental results revealed that vegetation markedly reduced the overtopping and sloping velocity and also revealed no supercritical flow condition both on the d/s slope and bed of embankment model which is the main influencing factor for causing overtopping erosion. Index Term-- Earthen embankment, vetiver grass, overtopping flow, vegetation, erosion. I