MODELING SPATIAL SEDIMENT DELIVERY IN AN ARID REGION USING THEMATIC MAPPER DATA AND GIS

A distributed parameter sediment delivery model is linked with persona l computer-based, low cost, geographic information system (GIS) to fac ilitate preparation, examination, and analysis of spatially distribute d input parameters as well as to link the sediment delivery from a mic ro scale To the watershed scale. The heterogeneous and complex land su rface within the watershed divided into grid cells of 30 x 30 m. Data on vegetative cover are derived from the digital analysis of Landsat T hematic Mapper. Spatial sediment delivery in an arid drainage basin in Argentina is analysed through preprocessing by GIS, calculation of se diment delivery, and post processing and display of spatial output in the GIS. The model accurately predicts, even for the same values of fl ow shear stress, the higher sediment delivery from bare surfaces as co mpared to surfaces protected by vegetative cover. This study enables t he identification of vulnerable regions within a watershed, thus facil itates improvement in planning of soil conservation systems.