Hazard Risk Assessment along the Karambar River in Gilgit Baltistan: A Karakoram Anomaly Affected Region

Abstract

The northern parts of Pakistan are particularly vulnerable to natural disasters, however comprehensive threat analysis and multi-hazard risk assessment can help to lower the risks. Pakistan's glaciers exhibit the Karakoram Anomaly, with increasing glacier mass leading to ice-dammed lake formation and subsequent outburst flooding. The primary objective of this study was to investigate the changes in river morphology caused by Glacial Lake Outburst Flood (GLOF) events over a span of three decades. To achieve this, the Digital Shoreline Analysis System (DSAS) model and Geographic Information System (GIS) techniques were used, which enable multi-hazard risk assessment. By integrating Multispectral Satellite Imagery, Meteorological Data, and Digital Elevation Model (DEM), various hazards can be accurately mapped. Additionally, field surveys have been conducted to examine the knowledge and experiences of affected individuals, assess the potential GLOF risks, and determine the vulnerability of communities to the effects of such events. The study findings reveal that the Yasin River, Karambar River, and Gilgit River have experienced both erosion and accretion over the period from 1990 to 2020. The accretion and erosion rate for Karambar River during this period was 144.41 m/yr and 140.73 m/yr. Similarly, average accretion and erosion rate for the Gilgit River was 118.97 m/yr and 124.22 m/yr respectively, while for the Yasin River, they were 138.05 m/yr (accretion) and 152.76 m/yr (erosion). Overall, all three rivers have experienced erosion in the last three decades and a systematic approach will be very useful to disaster management authorities for hazard management. Integrated risk management approach will also promote sustainable mountain development.