Prioritization of Sub-watersheds for Erosion-prone Identification: A Study of Kiile Watershed, Arunachal Pradesh, India

Abstract

Watershed prioritization is a strategic procedure used to delineate the most erosion-prone sub-watersheds. Identifying these critical areas is paramount for the effective allocation of resources and the successful implementation of soil and water conservation measures at the watershed level. However, studies concerning the mountainous watershed of Kiile are limited. In this study, the prioritization of 10 sub-watersheds of the Kiile River was done to identify erosion-prone areas using quantitative morphometric analysis. The watershed and its drainage networks were delineated using ALOS PALSAR 12.5 m resolution DEM in ArcGIS 10.4. For prioritisation, morphometric parameters such as linear, areal, and relief aspects were considered and calculated using standard formulae provided by various hydrologists and geomorphologists. Each morphometric parameter was preliminarily ranked based on its relation with soil erodibility. The final prioritization was done based on the compound value (Cp). The analysis result revealed that SW-8 and SW-5 are the most erosion-prone sub-watersheds with the lowest compound value, indicating greater susceptibility to erosion. Based on the results, the sub-watersheds of the Kiile River were categorised into four priority classes: very high, high, medium, and low. The SW-8 and SW-5 fall under the very high priority class, SW-3, SW-4, SW-6, and SW-9 fall under the high priority class, SW-1, SW-7, and SW-2 fall under the medium priority class, and SW-10 falls under the low priority class. This study significantly contributes to the management of mountainous watersheds and may be useful for decision-makers in sustainably managing and conserving the watershed resources.