Remote Sensing and Gis Approach for Watershed Monitoring and Evalution: a Case Study in Orissa State, India

Dry land farming in India accounts for 63% of the cultivated land of 144 million hectares. The crop production on these lands is dependent entirely on the natural precipitation, which is highly erratic in terms of spatial and temporal distribution during the crop-growing season. To address these problems, Government of India has accorded high priority to watershed approach for development of rainfed areas through National Watershed Development Project for Rainfed Areas (NWDPRA). The project aims at in-situ moisture conservation primarily through vegetative measures to conserve rainwater control soil erosion and regenerate the green cover both on arable and non-arable lands. The present study is towards monitoring and assessment of changes in the watersheds spread over 3 districts of Orissa state using remote sensing technology. The Indian Remote Sensing Satellite (IRS), Linear Image Self Scanning Sensor (LISS II) data of 1988 and 1996, pertaining to the pre and post treatment periods of each watershed have been analyzed. Classified and Normalized Difference Vegetation Index (NDVI) outputs of two time periods were compared to derive information, on changes that occurred over a period of time in the watershed. The study revealed an increase in the area under cultivation, water bodies, plantation and tree cover as a result of watershed management. Improvement and progressive changes ranging from 4 to 27.4% have been observed within a span of 5 to 8 years. Further, saturation index was derived for some of the watersheds under study for the assessment of implementation of NWDPRA developmental activities.