Assessment of bank erosion and its impact on land use and land cover dynamics of Mahananda River basin (Upper) in the Sub-Himalayan North Bengal, India

Abstract

Abstract Bank erosion is the predominant character of River Mahananda in the Sub-Himalayan North Bengal. The present study aims to identify the bank erosion mechanism as well as the impact of river bank erosion on land use and land cover (LULC) dynamics of the study area. Survey of India (SOI) topographical map 78 B/5 (1975) and satellite imageries for the temporal year of 1991 and 2019 from USGS have been used for the study. For the assessment of bank erosion process Bank erosion hazard index (BEHI) model has been adopted here. The channel migration has been delineated by the superimposition of temporal bank lines extracted from the temporal satellite imageries. LULC analysis has been carried out through the supervised classification technique using remote sensing and GIS tools. Form the assessment of BEHI it can be visualized that the scores have been ranging from 30.75 to 44.30 which indicates high to very high vulnerable areas under fluvial erosion. The channel migration for the temporal period from 1991 to 2019 is ranging from 7.72 to 411.16 m along the studied reach which reflects the high erosion effectiveness. From LULC classes it has been assessed that settled or built-up areas have been increased and the water body is gradually decreased overall in the study area. The study resulted that the river bank erosion has its direct impact on land use of the studied area. In the study vulnerable sites to fluvial erosion have been delineated and unplanned land use can be managed through sustainable way.

Keywords

• Bank erosion
• BEHI
• Channel migration
• LULC
• Accuracy assessment