Identificação do Parâmetro Curva Número para uma Sub-bacia da Encosta do Sudeste do Rio Grande do Sul

Abstract

The quantity and quality of the water resources of a river basin is a reflection of the use and occupation of the soil. Actions such as uncontrolled occupation, river channeling and soil sealing have altered the natural characteristics of basins, influencing the runoff and the infiltration rates of water in the soil, which can cause problems in the components of the hydrological cycle. Thus, the need for information on soil characteristics is essential for better river basin management. The Soil Conservation Service Curve Number (CN) method is widely used to estimate the runoff hydrograph, however, data are lacking for obtaining the CN parameter for brazilian conditions, specifically for the south of the country. This study aimed to identification the CN for a sub-basin of the Moreira stream, located in the southern end of the state of Rio Grande do Sul, in order to provide specific data for the of the hydrograph of local surface runoff. Through the characterization of hydrological groups and soil coverings, using geotechnologies to compile these characteristics, the CN 82 value was determined for the Fragata sub-basin, belonging to the hydrographic basin of the Moreira stream. The methodology used was adequate and can be used to support issues related to water resources planning, serving as management support.