Modelagem hidrossedimentológica em diferentes cenários de uso do solo na bacia do Rio Cobres, Portugal

Abstract

Soil erosion is a major environmental problem worldwide, mainly in semiarid regions that suffer with spatial and temporal variability of rainfall. In order to study the soil erosion problem, the use of runoff-erosion models coupled to Geographic Information Systems is an important tool to quantify the runoff and sediment yield process in the watersheds. Thus, this research analyzed the runoff-erosion process at the Cobres River Basin, located in the semiarid portion of Portugal, using the SWAT model. In this study, rainfall, temperature and humidity data from 1960 to 2000, and digital maps of land cover, terrain digital elevation model with spatial resolution of 90 m, and soil types were used. The results showed the effectiveness of the model for the runoff simulation, with coefficient of determination (R2) = 0.81 and Nash-Sutcliffe coefficient (COE) = 0.63, and also for the sediment yield simulation with R2 = 0.82 and COE = 0.47. Comparing the simulation results between the current usage scenario and the other two scenarios, the model increased the prediction of sediment yield in the basin in Scenario 1. As expected, in Scenario 2, the results of sediment yield were lower. In current usage scenario, the production of simulated sediment was 4.87 ton/ha/year.