A GIS BASED TOOL FOR THE SEDIMENT DELIVERY RATIO COMPARISON

The note deals with a new tool implementation for evaluating Sediment Delivery Ratio (SDR) in a river basin, through GRASS GIS software. The definition of a spatially distributed value of SDR is a very important task as the sediment routing can affects losses of soil productivity, increase of solid transport in stream channels, and water quality degradation. For such reason the SDR evaluation, coupled with GIS approach, has been extensively used in scientific literature. Geographic information systems provide a fundamental support for a better prediction of SDR, since it can consider the space variability of factors influencing the sediment routing processes. Actually a specific GIS module to estimate the spatial variability of SDR does not exist. We implemented a GRASS GIS module (in python language) called r.sdr where the sediment delivery ratio is evaluated by GIS procedure using several equations available in literature. We applied the tool to the Feo Creek watershed, located in the Apennines area of northeastern Umbria (Italy)