Prioritization of sub-watersheds in the Lish tributary of the Teesta River Basin
Prasanya Sarkar, Shasanka Kumar Gayen
Abstract
The study prioritises and regionalises sub-watersheds within the Teesta River Basin to evaluate erosion. The study develops a comprehensive framework for assessing erosion susceptibility by integrating morphometric parameters like stream order (U), number of streams (Nu), bifurcation ratio (Rb), stream length (Lu), drainage density (Dd), stream frequency (Fs), basin length (L), basin width (W), length–width ratio (L/W), basin area (Au), basin perimeter (P), elongation ratio (Re), circulatory ratio (Rc), and shape factor (Bs) with Multicriteria decision-making (MCDM) techniques like Preference Selection Index (PSI), Standard Deviation (SD), Criteria importance through intercriteria correlation (CRITIC), Entropy, Method based on the removal effects of criteria (MEREC), and Full Consistency Method (FUCOM). By classifying the sub-watersheds according to their risk levels, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) provides a methodical approach to rank the areas that require intervention in order of importance. Tailored management solutions can be implemented by grouping sub-watersheds into three categories according to the degree of erosion danger. The analysis provides insights for effective resource allocation and identifies high-risk regions (e.g., Subwatershed 19 and Subwatershed 13) that require rapid erosion control measures.