Prioritization of sub-watersheds of Gagas river valley using remote sensing and GIS

Watershed prioritization based on morphometric analysis is important for soil and water conservation and management at micro level. Remote sensing and GIS are effective tools for prioritization of sub-watersheds. Gagas river valley watershed located in Almora district of Uttarakhand has been taken up for the study. The watershed was divided into 11 sub watersheds and the morphometric analysis of areal, linear and relief parameters was done by using ArcGIS software. The morphometric parameters that affect the soil erodibility are considered to prioritize the sub watersheds and assigned ranks on the basis of relationships with erodibility so as to arrive at a compound parameter (Cp) value for final ranking of each sub watershed. The sub-watershed with the lowest Cp value has been given the highest priority and then categorized the subwatersheds into three classes as high, medium and low in terms of priority. The analysis reveals that high priority zone consists of four sub-watersheds (22.66 sq.km), medium of five (20.56 sq.km) and low of two sub-watersheds (10.51 sq.km). The sub-watersheds which are falling under high priority are much more susceptible to soil erosion and should be given high priority for land conservation measures.