Diagnosis of environmental degradation for hydric erosion in the Napostá Grande stream’s basin

Abstract

We carried out an environmental degradation diagnosis in the Napostá Grande stream’s basin, Ventania system, province of Buenos Aires, to identify water erosion factors that result in environmental degradation. We based our diagnosis of the present situation of the basin on: (a) a qualitative assessment in the field, supported by satellite images and aerial photographs, of drainage, climate, landscape, soil, geology, vegetation and current land use, and (b) a quantitative diagnosis based on the application of the hydrological model HYMO 10, calculating water flows for a typical storm in the study area, and solid discharge estimates with the USLE (universal soils loss equation) method and its extension to small basins (MUSLE; modification of the universal soils loss equation). The correlation between the qualitative and quantitative diagnoses allowed the identification of sites where degradation by water erosion affected the sustainability of the system. The determination of the loss of superficial soil, influenced by the scarce vegetation cover, indicated an improper use of lands and slopes, fostering a potential economic and productive downgrading of soil and water.