Interrelations Between Soil Erosion Conditioning Factors in Basins of Ecuador: Contributions to the Spatial Model Construction

Soil erosion due to the effect of surface runoff is one of the main environmental concerns inherent in the management plans of the hydrographic basins in Ecuador. The objective of this work was to analyze the interrelationships between the conditioning factors of soil erosion in hydrographic basins of the Ecuadorian territory, as an input for the construction of a spatial model of soil loss. The methodology considered the delimitation of the hydrographic basins, the calculation of elevations and slopes, the classification of land cover, lithology and R factor in Ecuador. The basins delimitation, calculation of elevations and slopes, were carried out from a DEM of 4 km of resolution; the land cover information was obtained from the Global Land Cover Database; the lithology factor was retrieved from the World Global Lithological Map Database; and the R factor were processed from the Global Rainfall Erosivity Database. The results indicated that the average elevation of the Ecuadorian basins ranges between 57 m and 2200 m. The average of the slopes decreases the greater the distance to the Andes Mountain, showing a greater variation in the basins that drain towards the Pacific. Most of the vegetation cover of the ground corresponds to closed forests and herbaceous vegetation. There is a great variety of lithological outcrops of different natures, which gives them different levels of erodibility. The R factor showed a similar behavior in the areas close to the Andes while, in the sectors close to the Pacific Ocean, the values were more dispersed.