Morphometric analysis and prioritization of sub-watersheds using GIS and Remote Sensing techniques: a case study of Odisha, India

摘要

The study area is one of the watersheds of Tel river, covering an area of 1515.45 km2 and lies between 19° 17′ and 20° 00′ N latitude and 82° 30′ and 82° 59′E longitude in Bhawanipatna area of Kalahandi district, Odisha, India. Poor soil cover, sparse vegetation, erratic rainfall and lack of soil moisture characterize the study area for most part of the year. Recurring drought coupled with increase in ground water exploitation results in decline in the ground water level. So the entire study area has been further divided into 12 sub-watersheds named SWS-1 to SWS-12, ranging in geographical area from 30 km2 to 202 km2 and has been taken up for prioritization based on morphometric analysis using GIS and remote sensing techniques. The drainage density of sub-watersheds varies between 1.09 to 3.36 km/km2 and low drainage density values of sub-watershed SWS-11 indicates that it has highly resistant, impermeable sub-soil material with dense vegetative cover and low relief. The elongation ratio varies from 0.6 - 0.8 which indicates high relief and steep ground slope. The high value of circularity ratio for SWS-11 sub-watershed (0.8) indicates the late maturity stage of topography. This anomaly is due to diversity of slope, relief and structural conditions prevailing in this sub-watershed. The compound parameter values are calculated and the sub-watershed with the lowest compound parameter is given the highest priority. The sub-watershed SWS-1 has a minimum compound parameter value of 4 is likely to be subjected to maximum soil erosion and susceptible to natural hazards. Hence it should be provided with immediate soil conservation measures.