Validation of BANCS model for assessing stream bank erosion hazard potential (SBEHP) in Bakreshwar River of Rarh region, Eastern India

Abstract

It is often difficult to assess stream bank erosion. Bank Assessment for Non-point source Consequences of Sediment (BANCS) model is a renowned procedure for evaluating Stream Bank Erosion Hazard Potential (SBEHP). In the present article inventory of stream bank condition have been assessed from field surveys on 24 sample segment over a consecutive 5 year period for 86.36 km stretched river Bakreshwar of Eastern India. Bank Erosion Hazard Index (BEHI), Near Bank Stress (NBS) and field based data have been considered for this appraisal. The results show that (1) BEHI is high in the upstream and near the confluence segments. (2) Compare to BEHI, NBS is less for most of the sites. (3) Fragile lateritic soil, sparse vegetation, etc., in the upstream and steep slope and barren bank, sinuous channel, loosely compact alluvial sediments, etc., in the downstream can be accountable for high SBEHP in those counterparts. (4) On the annual basis, a total of about 173595.75 metric tons of sediment entrains into the river from banks. (5) Banks have experienced varied rate of erosion from similar BEHI–NBS combinations. Therefore, we concluded that BEHI and NBS is potentially not a sound bank erosion hazard predictive model for our present study.