IMPACT ASSESSMENT OF WATERSHED IN DESERT REGION

Abstract. Change detection from different temporal images usually based on reflectance on natural and human activity impact, using integrated GIS, Remote Sensing and image processing technologies enable impact assessment of watershed in desert region. A time series analysis of seasonal NDVI have been used to estimate net primary productivity, phonological characteristic of vegetative surface, length of growing season and dry drown periods (Ramsey et al., 1995). The study is designed to achieve the objectives to Study the changes in vegetation for selected watershed in a desert districts of Bhilwara, Barmer & Jaisalmer in Rajastan State of India, to identify the changes in density of vegetation, to assess the temporal changes and to assess the impact of the watershed, with an objective to conserve the soil erosion and harvest the rainwater in order to increase the ground water table, to improve the socio economic condition of the people and to stop the migration of the people from the villages in search of livelihood. These activities will have a direct impact on the crop production. The Changes in density of vegetation indicates the quantity of crop production and the growth of vegetation apart from crops and the conservation of land with out scrub/barren land to land with scrub. This gives an picture about the impact of watershed programme in increasing the vegetative cover. The temporal changes help in understanding the changes taken place in the watershed, and facilitate understand the positive as well as negative impacts of any decisions taken in the implementation. The extent and density and type of vegetation for the years, 2000,2004,2005,2007 and 2008, was studied and vegetation growth was analysed using GIS and Digital Image Processing techniques.