Hunza river watershed landslide and related features inventory mapping

Abstract

This study summarizes the continuation of a series of regional landslide inventories undertaken in Northern Pakistan. Mass wasting appears to be the dominant process shaping the morphology of the main river channel in the Hunza River watershed. The project included assembling an inventory of historic mass wasting features in the basin, especially, those along the Hunza River. A hillshade topographic map was created by stitching ASTER Digital Elevation Models (DEMs) with 30 m resolution topographic sheets of 40 m resolution, using ArcGIS. The methodology utilizes anomalous topographic expression (i.e., parallel and converging drainage patterns, divergent contours, crenulated contours, and isolated knobs) to identify landslide features. The screening process includes examination of topographic anomalies and inconsistencies, which are typical of landslides and related mass wasting features. The mapped landslide features included a number of historic landslides in the area. Historic landslide damming of the Hunza River has occurred at Attabad, Boultar Glacier, Gannish-Chiss, and Ganesh-Saukien. The outbreak floods associated with the overtopping of these recent landslide dams often leave anomalous geomorphic signatures, which were identified in the terrain analysis, and helped validate the interpretations made as part of this study. Such products serve as guide maps for more detailed analyses of specific sites, as might be under consideration for structures, highways, tunnels, dams, powerhouses, or utility corridors.