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Soil erosion risk zoning in the ecuadorian coastal region using geo-technological tools

Abstract:

The activation of erosive processes on the slopes of the drainage catchments in the Ecuadorian coastal region represents a serious environmental problem that results in a loss of soil resource with the consequent reduction in agricultural productivity, increasing lack of areas with vegetation, and decreased water quality. These issues increase, among other things, the probability of flooding. The purpose of this research is to zone soil erosion risk in the Manabí province, which is located on the Ecuadorian coast. The methodology is supported by the employment of Geographic Information Technologies (GIT) in order to access and process information of interest, such as: precipitation data with which to calculate the R Factor of the Universal Soil Loss Equation (USLE); topography, which was employed to create a slope map from the Digital Elevation Model (DEM) ASTER; vegetation cover, by applying the Normalized Difference Vegetation Index (NDVI); land use, through the interpretation of orthophotos and a field survey; and infiltration capacity, obtained by considering the texture of the soil. The factors were combined by means a weighted relationship (map algebra) and exploiting the potential of software for the design of Geographic Information Systems (GIS). The results indicate the presence of soils with little or limited vegetal protection, in areas with steep slopes, moderate rainfall and extensive farming activities. These characteristics determine conditions of high soil erodibility, and propitiate the triggering of erosive processes. Indeed about 19% of the surface of the Manabí province classifies with soil erosion risk between high and very high. These areas should be prioritized by regional government agencies to implement soil restoration and protection policies. Surfaces with medium soil erosion risk represent 67% of the territory, which are also areas that require certain levels of attention. The surfaces with low soil erosion risk represent only 14% of the province, corresponding to areas of low slope.