Geo-spatial topology based morphometric analysis for soil and water conservation in Dholbaha watershed of Kandi region

Abstract

Morphometric analysis forms the basis for planning water and soil conservation treatments in a watershed. Geospatial topology based morphometric analysis in Dholbaha watershed, located in the Kandi region of Punjab, was carried out using the IRS data of LISS IV, Cartoset-1 merged satellite data, ASTER DEM and ArcGIS-10.2 software. As per topology, Dholbaha watershed is the 5th order watershed. Out of all the 279 streams identified, 213 are of 1st order and one 5th order stream. The total stream length is found to be 191.73 kms. The dendritic drainage pattern is found with stream frequency of 4.67 no./km2 and mean bifurcation ratio of 3.9. Both length as well as number of streams decrease with the increase in the order of streams. Topological model indicates lesser effect of geological structure on the drainage pattern of the watershed. Drainage density of watershed (3.21 km/km2) reflects the closeness of spacing in channels with permeable sub strata. Fine drainage texture (7.34 no./km) and large length of the overland flow (150 m) in watershed resulted into high peaked hydrographs and high sheet erosion in the watershed. The circularity ratio, form factor and elongation ratio of the watershed 0.412, 0.51 and 0.72, respectively indicate that watershed is less elongated in shape, associated with medium to high relief, having moderately permeable sub-soil conditions resulting in moderate peak discharge, and moderate runoff volume resulting in high soil erosion. The watershed requires urgent conservation measures to control siltation of the reservoir.