Himalayan hazardscape a study of upper Mandakini river basin

Abstract

The present study Himalayan Hazardscape: A Study of Upper Mandakini River Basin sought to understand hazardscape as a result of the human-environment interface in the Mandakini river basin of the state of Uttarakhand. Hazardousness was studied in terms of spatio-temporal occurrence of disasters, accounted for by the physical susceptibility of the study area, further governed by geo-physical attributes, and compounded by human vulnerability to result in spaces of disaster risk. The study focused on disasters such as landslides, earthquakes, cloudbursts and flash-floods. The quantitative analysis on the spatial scale was carried out using ArcGIS while ALOS PALSAR Digital Elevation Model was used to evaluate the geophysical attributes. It emerged that the region had recorded 116 earthquakes since the year 1816 and 102 landslide events and 18 cloudbursts and flood events in the preceding two decades. While earthquakes were the handiwork of geological factors, flash-floods and landslide resulted from tectonic and geomorphic characteristics in combination with heavy rainfall. A cumulative hazard index based on multivariate analysis showed that nearly 45 per cent area exhibited high susceptibility to multiple disasters especially in the valley floor and side slopes situated in close proximity to rivers. While the majority of the villages with high human vulnerability lay between Madhyamaheshwar River valley and Mandakini River valley; a few were located in the south-western part of the study area. The analysis reveals that spaces of high disaster risk spread over 50 per cent of the inhabited area also lay primarily between these two river valleys. newline