IDENTIFICATION OF CRITICAL EROSION PRONE AREAS FOR WATERSHED PRIORITIZATION USING GIS AND REMOTE SENSING

Abstract

Soil erosion is a serious environmental problem as it increases level of sedimentation in the river and reservoir; reduce their storage capacity and life, causes flood due to reduction in carrying capacity of rivers and streams. To restore the productivity of the soil and prevent further reduction of storage capacity and life of reservoirs, the information on sources of sediment yield within a catchment should be given high priority for conservation of soil resources. Conservation of natural resources especially for soil and water carried out on a watershed basis are very useful for watershed management. In this context, prioritization of watershed based on different watershed components is required for any further relevant conservation measures. The Haharo sub catchment having an area of 565 Km2 in the Damodar-Barakar catchment of Upper Damodar Valley (UDV) area in Jharkhand State in eastern India is taken up for the present study. The catchment is selected due to availability of gauged data at multiple locations at, Sirma as (4/I), Barkagaon as (4/2), Bisrampur as (4/3) and Simratari as (4/4) within this watershed. The major factors responsible for soil erosion include rainfall, soil type, vegetation, topographic and morphological characteristics of the basin. Surface erosion and sediment yield quantities are found to have large variability due to the spatial variation of rainfall and catchment heterogeneity. This study is, therefore, undertaken to use conventional Morphometric analysis to assess the vulnerability of watersheds with respect to time-independent factors likes soil type, topography and morphology, and to use most widely accepted empirical Universal Soil Loss Equation (USLE) with transport limiting u sediment delivery (TLSD) concept to compute soil erosion and sediment outflow in GIS environment utilizing remotely sensed data and other data for assessing the vulnerable soil erosion areas within a watershed. The ArcGIS package has been used for carrying out geographic analysis and Earth Resources Data Analysis System (ERDAS) Imagine image processor has been used for the digital analysis of the satellite data for deriving the land use land cover characteristics of the catchment.