Watershed prioritization using remote sensing and GIS-A case study from Guhiya

Abstract

Land resource development programmes are applied generally on a watershed basis. Delineation of watersheds within a large drainage basin and their prioritization is required for proper planning and management of natural resources for sustainable crop production. An integral part of Guhiya basin (with an area of 1614 km2) was studied for priority watershed delineation with the objective of selecting watersheds to under take soil and water conservation measures using remote sensing and Geographical Information System (GIS) techniques. Using the terrain information derived from geocoded satellite data and 1:50,000 topographic maps, 68 watersheds were assessed on the basis of their erosivity and sediment-yield index values. Thematic maps of land form, land-use and land-cover, and slope were digitised using ARC/INFO. On the basis of sediment yield index values the watersheds were grouped into very high, high, moderate and low priorities. High priority watersheds with very high SYI value (>150) need immediate attention for soil and water conservation whereas, low priority watershed having good vegetative cover and low SYI value (<50) may not need immediate attention for such treatments.