Sediment yeld from mountain scope: a GIS based automation of classic Gavrilovic method.

Sediment yield and slope erosion represent nowadays an open problem for Alpine river basins management. In last decades a variety of methods to estimate erosion rate and yield volumes have been studied and presented to scientific community; however these methods are often empirical and only provide rough results. On the other hand the use of physical based methods demands an enormous quantity of data that are difficult and costly to collect. Moreover these data are affected by an intrinsic error due to the impossibility of taking accurate parameters measurement. This paper focus on Gavrilovic method that is considered a standard for erosion evaluation in Alpine regions; this theory has proved to be effective and quite simple to be applied, but has a major drawback in the subjectivity of parameters determination. Since 1973, when this method was initially published, many things have changed and computers revolutionized the scientific world. Authors are convinced that the use of a GIS support can automate Gavrilovic method. GIS uses advanced calculation methods based, on high resolution geographic data; these datasets allow to eliminate or at least reduce the role of operator in the calculation processes. Moreover the whole basin can be automatically split in little sub basins with similar features. This operation leads to an application field more similar to the original testing site. The final objective is to present an automated process that can produce a reliable prediction of sediment yield from little and medium basins starting from DTM and use of soil maps, taking into account also the rainfalls distribution on the studied area. The new method is then applied to a test site to demonstrate the improvements in time and efficiency this innovation can lead to.