Morphometric and Principal Component Analysis Based Approaches for Prioritization of Rupnagar Watershed of Punjab, India

Land with undulating topography, high rainfall intensity and less vegetative cover, like that in Kandi region of Punjab, India, is prone to severe soil erosion. It is necessary to prioritize different zones/portions of such land to implement soil conservation measures. In this study, 10 sub-watersheds of Rupnagar watershed were delineated for morphometric analysis and prioritized for implementation of soil conservation measures. Linear, areal, relief and shape parameters of the sub-watersheds were estimated and utilized for sub-watersheds’ prioritization by employing morphometric and principal component analysis (PCA)-based approaches. The results showed that the mean bifurcation ratio varied from 1.61 to 3.63, suggesting that sub-watersheds belonged to normal basin category. Drainage density varied from 2.24 to 3.035 km km-2. The sub-watersheds SW-8, SW-9, and SW-1 had highest value of drainage density indicating lower infiltration rates and higher surface flow velocity often leading to a high sediment yield and high flood peaks. The low values of drainage density indicated that permeable subsoil material and sites were favourable for groundwater recharge. In PCA-based approach, parameters such as relative relief, relief ratio, channel gradient, and Melton ruggedness number were found strongly correlated, whereas stream frequency was moderately correlated in the rotated first factor-loading matrix for the first principal component. The second principal component was found strongly correlated with elongation ratio and form factor. In morphometric approach, sub-watersheds SW-1, SW-3 and SW-2 got the first three ranks, which were similar to priority ranks assigned in case of PCA-based approach. The sub-watershed SW-1 got a common rank by both the approaches indicating towards high vulnerability to soil erosion. Appropriate soil conservation measures are required to be implemented at priority in this sub-watershed and alike. Last priority rank was assigned to sub-watershed SW-8 by both the approaches. The results of this study would help in implementing soil conservation measures in highly prioritized sub-watersheds