Morphometric Analysis of Watersheds of Thalisain Area Himalaya for Assessing Their Fluvial Erosion Susceptibility Using Geomatic Techniques

Abstract

To assess the fluvial erosion susceptibility of watersheds Drainage Morpometric analysis was carried out in Thalisain region of Pauri district, Uttarakhand in India. The SOI toposheet and ASTER DEM were made in use for preparation of drainage and watershed boundary. All the Morphometric parameters related to linear, aerial and relief, drainage gemorphometry was calculated for all the watershed and weightages were allotted to them to drive Composite Weightage Value (CWV). Consequently, by grouping these calculated values of the watersheds were categorized in to four classes such as low, moderate, high and very high watersheds erosion susceptibility. The correlation of CWV with morphometric parameters showed that the high stream frequency, coarser texture, high relief and low length of overland flow control the drainage pattern in the region. It was also observed that among land use/ land cover, agriculture land is major factor governing soil erosion. Geologically, it is influenced mainly by the Quaternary Alluvium and unconsolidated rock formations of the terrain. It was revealed that 4.53% area is prone to low erosion, 33.49 % is prone to high erosion, 22.79% is prone to medium erosion, and 39.20% area is prone to very high erosion. Therefore the study suggests that the soil and water conservation measures are required in the watersheds to control the fluvial erosion.