GIS-based landform and LULC classifications in the Sub-Himalayan Kaljani Basin: Special reference to 2016 Flood

Abstract

Progress in GIS technology has facilitated the topographic position index (TPI)-based auto-classification of landform units. Multispectral satellite images, when used along with terrain analysis output, provide valuable information on structure, soil, land use land cover (LULC), hazards etc. The present work makes an endeavour to classify landforms using TPI and assess its distribution pattern across different LULC segments in the Kaljani River Basin of the Sub-Himalayan region. An attempt is also made to analyse the inundation pattern during the most recent major flood (2016) across the landform and LULC units.The Kaljani Basin is occupied by upper slopes, mountain tops and gorges in its upper (northern) part, while its lower (southern) part is characterised by wide valleys and plains. The areas occupied by gorges and midslope drainages in the hills, and wide valleys in the foothills, are comparatively more exposed to fluvial erosion, as found from the topographic wetness index (TWI). LULC classification reveals that the northern and central parts of the basin have plenty of vegetation cover. Land use units like fallows, farmlands and built-up areas are more common in the southern part of the basin. During the flood of 2016, three-fourth of the total inundation occurred in the wide valleys and plains. More than 90% of the inundated areas are found in the human-modified terrain, indicating its susceptibility to the flood hazard.

Keywords

• Himalayas
• ALOS PALSAR DEM
• Topographic position index
• Landform classification
• LULC
• Flood