Land degradation and erosion risk analysis in S.E. Spain: A geographic information system approach

Abstract

This study demonstrates the use of a Geographic Information System (GIS) for monitoring land use change, land degradation and erosion risk in the Albudeite catchment, S.E. Spain. A land use classification of the area was obtained by Air-photo Interpretation (API). Two sets of air-photos (1957 and 1986) were interpreted enabling land use changes over the 29 year period to be assessed. Gullied areas were also mapped from 1986 photographs and used to compute gully density. A Digital Elevation Model (DEM) derived from elevation contours was used to calculate terrain parameters, such as slope and aspect. The land use data were analysed together with DEM, slope, and aspect using a GIS to study the distribution of land use and land degradation features, and to monitor land use changes. An erosion risk map of the area was also produced by combining land use, gully density and slope data using the GIS. It was found that nearly 50% of the total area is susceptible to erosion risks, ranging from moderate to very severe, and that 56% of the cultivated land is threatened by these risks. Slopes of between 2–8° were found to be critical as both land use changes and erosion risks were greatest at these gradients.