Evaluating stream bank instability and toe erosion using BSTEM model for the Amu river

Abstract

Loss of land, disputes on sharing costs, and benefits of transboundary waterways are points of debate between neighboring countries. Unfortunately, weak, undeveloped countries always suffer more than their stronger neighbors. Due to economic, political, and institutional problems, Afghanistan is one country that faces challenges to develop the potential of its water resources. Each year, Amu River flooding causes great losses of land due to massive bank degradations and erosions for up to several kilometers. Currently little progress has been made to study, research, or manage the bank erosions of the Amu River. In the absence of field data, the Bank Stability and Toe Erosion Model (BSTEM) may be used to analyze stream bank stability and toe erosion. This study was conducted to describe the Amu River stream bank using the BSTEM model for a restoration process. A field survey was conducted from February 3, 2019, to February 23, 2019; soil type, layer thickness, water table depth, and stream bank profile are entered into the BSTEM model with two different flow depths according to insights from villagers and well-diggers. Mass failure and toe erosion are two dominant mechanisms of Amu River bank failure, and the effectiveness of vegetation on bank protection is observed.