Estimativas de cargas poluidoras difusas em bacias hidrográficas, com ênfase nas cargas geradas para o parametro fósforo

摘要

Water is an essential factor in the formation and maintenance of life. However,?the water sources have suffered a strong impact on the quantitative and qualitative?aspects. This paper aims at contributing to the understanding of the water quality?problem related to nonpoint pollution sources. ArcView Generalized Watershed?Loading Function (AVGWLF) model was used to demonstrate the phosphorus loads?generated in an experimental watershed. Maps were created such as: land use and land?cover, soil types, rivers, phosphorus concentration in the soil, among others, used as?input files of the model. Four scenarios of land use and land cover were also created,?namely, native and eucalyptus forest, pasture, coffee and bare soil and then the loads of?phosphorus generated for each scenario were compared between 1998 and 2002. The?parameter MU_AWC has a strong influence on the generation of the phosphorus load?in groundwater, in simulations, because the increase of the parameter value reduces?the simulated load. The results simulated by the model for the monthly charges follow?seasonal variations in rainfall. The simulated values of phosphorus vary quantitatively?in the following order, considering the scenarios of land use: native and eucalyptus?forest, pasture, coffee and bare soil.