Drainage Morphometry–Based Prioritization of Sub-Watersheds in the Kalrayan Hills (India): Morphometric Characterization, Statistical analysis, and CF–WSA Ranking

Objectives: To select eight sub-watersheds (WS1-WS8) in the Kalrayan Hills (Tamil Nadu, India) to conserve soil-water through the drainage morphometry and terrain attributes of the terrain using the DEM. Method: Slope and elevation from SRTM 30 m DEM, along with a Strahler-ordered drainage network (max order 6) and validated sub-watershed boundaries were used to calculate standard linear, areal and relief morphometric parameters. Correlation and principal component analysis were used to evaluate parameter redundancy and dominant controls. Prioritization was done using Compound Factor ranking and Weighted Sum Approach with normalized indicators. Priority classes are Very High (WS3 and WS4), High (WS5 and WS6), Moderate (WS2 and WS7), and Low (WS1 and WS8). Findings: Very-high priority units exhibit greater drainage development and/or relief energy, which suggests greater runoff and erosion susceptibility. Strong agreement between rankings using both methods (Spearman r = 0.952; p = 0.00026). Novelty: The integrated CF–WSA framework provides a rapid, decision-ready basis for phased conservation planning in data-limited mountainous watersheds. Keywords: Sub-watershed prioritization, SRTM DEM, Compound factor, Weighted sum approach, Eastern Ghats