TR(BR)-2/97-98 : Soil erosion and sediment yield modelling using Kinematic wave in GIS environment

Abstract

GIS techniques have been utilized to spatial discretization of a catchment in to time-area segments to be used in numerical solutions of the governing differential equations for rainfall-runoff-erosion process. Various thematic layers such as soil, landuse, slope, flow direction, DEM were generated for the Karso catchment using various tools available in GIS. These thematic layers were further utilized to generate attribute information such as Manning's n, USLE K and C parameters for use in rainfall-runoff-soil erosion model. Based on DEM and related attributed information of the catchment, time-area map of the catchment was prepared and used for spatial discretization of the catchment.

Rainfall abstraction has been carried out by phi-index method. The excess rainfall falling on each of the time-area segments was routed to outlet using numerical solutions of kinematic wave equation using fully implicit four-point finite difference scheme. The sediment yield has been estimated by solving sediment continuity equation using fully implicit finite difference scheme. Comparison of results indicated applicability of this modelling concept for Karso catchment.