Erosion risk assessment through morphometric indices for prioritisation of Arjuna watershed using ALOS-PALSAR DEM

Pressure of growing population rates and unsustainable usage of resources have greatly affected the productivity of agricultural lands due to land degradation. In a developing country such as India, degradation of land happens mainly due to the action of fluvial resources. The morphometric analysis of the drainage basin and channel network gives a detailed understanding of the geo-hydrological behaviour of drainage basin and expresses the prevailing climate, geology, geomorphology, and structural antecedents of the catchment which is very decisive in identifying regions vulnerable to soil erosion. Advancement in Remote Sensing (DEM) products and GIS techniques has made the assessment of morphometric indices more accurate, effective and less time consuming. Therefore, in this study, to assess the vulnerability of soil erosion in Arjuna watershed of vaippar basin, morphometric indices-based prioritisation of 16 sub-watersheds have been carried out using high-resolution ALOS-PALSAR DEM with a spatial resolution of 12.5 m. The linear and shape parameters which are responsible for soil erodability are assigned ranking using Compound Factor (CF) technique to arrive at the prioritisation of sub-watersheds. Based on the CF values, sub-watershed are classified into three categories of priority as high (5–7), medium (7–9), and low (9–12), respectively. The sub-watersheds such as Kamba Ittu Malai, Arjuna Nadi, Mela Gopulapuram, and Kodikulam come under the high priority category, whereas Muvaraivenran, Thaniparai, Chittar River,Vadugapatti, Perumalswamiuchi, Ayan Karisalkulam, Kurukkamuttu malai, and Satpur R.F come under the medium priority category and the Ramachandrapuram, Arjunapuram, Kovil Aru, and Periyar River sub-watersheds come under the low priority category.