INTEGRATION OF REMOTE SENSING DATA WITH ANCILLARY DATA FOR WATERSHED PRIORITISATION

Abstract

Watershed management implies rational utilisation of land and water resources for optimal and sustained production with minimum hazards to natural resources and environment. It requires collection and analysis of a great deal of information on physical relationship of vegetation, soil and water, responsible for economic and social progress of a region. In order to minimise the cost management plans are normally based on highest priority watershed, which makes it mandatory to prioritise the watersheds. Watershed prioritisation is thus, the ranking of different subwatersheds according to the priority in which they have to be taken up for treatment. Remote sensing techniques are particularly suited to provide information on many watershed characteristics and hydrological parameters such as stream network, land use/cover, soil, surface water bodies etc. Remote sensing_ ,provides a valuable source of data to aid -sediment yield prediction. In the present study, remote sensing techniques have been applied for the assessment of sediment yield.. The present study is taken in Upper Yamuna Catchment which is found to have a major problem of erosion such as silting of rivers, floods in down stream, choking of culverts etc. Watershed is divided in twenty three subwatersheds and used for prioritisation based on the sediment yield. The parameter considered to get the •4 sediment yield from the. subwatersheds are land slope, rainfall-, landuse and drainage density. Sediment yield vary from 0.0859 cm/year fof subwatershed 7 to 0.0035 cm/year for subwatershed 22. It is found that three subwatersheds covering about 16 percent area of total area of watershed have the highest priority class, one subwatershed covering about 1.5 percent area of total area has high priority, five subwatersheds covering 29 percent area of total area have medium priority, and four subwatersheds. covering 16 percent area of total area have the low priority class. Remaining ten subwatersheds covering 37.5 percent area of total area have Lowest priority class. In these watersheds some conservation measures are suggested where remote sensing & GIS technology can be fruitfully utilised. iv