Acceptance of BANCS model for predicting stream bank erosion potential and rate in the left bank of Ganga river of Diara region in Malda district, North East India

Abstract

River bank erosion is a hazardous problem of Malda district. Different parts of Malda are mainly eroded by hydraulic action of River Ganga. Bank assessment for non-point source consequences of sediment model is a well accepted process for predicting stream bank erosion hazard potential. In the present study, river bank stability condition has been measured form field survey on 15 sample segments for 185 km stretched from Rajmahal in Sahibganj district, Jharkhand to upstream of Farakka barrage in Malda. In the present study, bank erosion hazard index (BEHI), near bank stress (NBS) and field based data have been considered for assessing stream bank erosion. The result shows that BEHI is high along the whole given left bank line extension of river Ganga, among these BEHI is very high in the upper segments of the river and adjacent river bank line extension of Farakka barrage, overall NBS conditions along left river bank line are less compare to the BEHI. Dominant NBS conditions are belong under moderate to low along the river bank line. Loosely compact alluvial soil, sparse vegetation, steep slope, unorganized agricultural activities; sinuous channel can be responsible for river bank erosion hazard potentiality. On an average 976,068.991 metric tons of sediments entrains to the river in a year. Bank has experienced variants bank erosion from same BEHI and NBS combinations. So, it can be concluded that BEHI and NBS are potentially not significant model for predicting bank erosion in present study.