Publicação on-line; 29 ref.; 2 tables; 8 illus.; Summary (En)

Abstract

This study aims to estimate the effect of different land uses around watercourses on runoff following extreme
precipitation events and, consequently, on the mitigation of these effects. The study area is a rural watershed
in the state of Rio Grande do Sul, Brazil. After characterizing the area, we estimated the surface runoff of the
January 2009 precipitation event, which caused two casualties: losses in soil and productive area, as well as over
US$ 300,000.00 in damages to the water supply system. Subsequently, simulations were performed considering
different land uses and riparian areas under different precipitation levels. The results indicate that conserving riparian
forests in the surroundings of watercourses decreases direct surface runoff, whereas intense soil use in these areas
favors runoff increase.

Keywords: conservation, forest hydrology, watershed management.