Prioritization of erosion susceptible watersheds using morphometric analysis and PCA approach: A case study of lower Sutlej River basin of Indian Punjab

Abstract

Morphometry helps in understanding the behaviour of drainage characteristics with respect to various hydrological processes including infiltration, runoff, erosion and sediment transport. Morphometric analysis of river basins is an essential technique to the study the response of drainage basin in response to topological characteristics. The river basins' morphometric analysis is an important technique to prioritize the watersheds for implementation of soil and water management strategies. In this study, the morphometric characteristics of the lower Sutlej River have been determined using the geo-spatial techniques. The river basin, having area of 8577 km², was delineated into the fourteen sub-watersheds (WS-1 to WS-14) in the GIS environment. The ALOS PALSAR DEM and ArcGIS were utilized to evaluate the morphometric parameters of the delineated watersheds. The calculated morphometric parameters were used to rank the watersheds in terms of soil erosion potential. The priority ranks to the watersheds were assigned as per compound parameter, which was calculated by averaging the ranks designated to each morphometric parameter. Watersheds with the lowest compound parameter values were given the highest priority rating, and vice versa. Based on the results WS-7 was assigned the first rank whereas WS-13 was assigned the 13th rank. The principal component analysis was performed to determine the highly correlated morphometric parameters. Out of the 18 parameters, 13 were found be highly correlated. The compound parameter obtained based on these highly correlated parameters also prioritized WS-7 as the most vulnerable watershed. Therefore, WS-7 should be selected for the implementation of soil and water conservation strategies. It can be concluded that morphometric analysis along with PCA in combination with GIS can be helpful in prioritizing the watersheds in terms of soil erosion vulnerability and water management.