A semi-automated approach for mapping geomorphology in mountainous terrain, Ferozpora watershed (Kashmir Himalaya)

Abstract

Mapping geomorphology in a mountainous terrain is very critical for understanding various land surface processes for their accurate quantification and prediction on different spatial and temporal scales. In the present study, geomorphological mapping was carried out in Ferozpora watershed of Jhelum using remotely sensed data supported by extensive field observations. Three approaches were adopted for mapping geomorphology of Ferozpora watershed. A geomorphological mapping model, Topographic Position Index (TPI), on Screen Image Interpretation (OSII) of satellite data and a hybrid approach utilizing information from TPI and OSII of satellite data were employed. Geomorphology of the area, mapped using the three approaches, was cross checked and verified with the ground data collected by extensively surveying the area and recording the geo-location of the geomorphological features using GPS. Overall, 12 different landforms were mapped which include Alluvial plains, Deeply incised streams, Glacial terrain, Highly dissected hills, Karewa, Fluvial landforms, Moderately dissected hills, Mountain ridges, River channel and U-shaped valleys. The study revealed that Hybrid approach, using inputs from TPI, OSII and field observations, is appropriate in mapping different geomorphological features in this topographically complex terrain with an overall accuracy of 91.53% as compared to TPI (45.56%) and OSII (77.82%) approaches. The study could be extrapolated to other parts of topographically complex Himalayan terrain so as to bring about a very high resolution geomorphological map of Himalayas which could aid policy makers, planners and earth scientists in better modelling the earth surface processes like soil erosion, landslides, hydrology, etc. in the region.