Classificação Hidrológica de Solos Brasileiros para a Estimativa da Chuva Excedente com o Método do Serviço de Conservação do Solo dos Estados Unidos Parte 2: Aplicação

TLDR: In this paper, the responses of the rainfall-runoff model of SCS applied to the original hydrologic soil classification and with the classification suggested by Sartori et al. (2005) to observed precipitation events in order to estimate excess rainfall and peak flow were compared to the events observed in the watershed.

Abstract: The rainfall-runoff model of the United States Department of Agriculture (USDA) Soil Conservation Service (SCS) is often used in engineering projects, either to calculate excess rainfall or for a design hydrograph. However, it is known that the main parameter of the method is the runoff curve number (CN). It is also known that the hydrologic soil classification is very important to estimate CN and it has not been developed for tropical soils such as those in Brazil. Sartori et al. (2005) point out a few difficulties for its application and present a suggestion for hydrologic soil classification in Brazil based on the work of Lombardi Neto et al. (1989). As all proposals deserve to be evaluated, this study is developed to analyze the responses of the rainfall-runoff model of SCS applied to the original hydrologic soil classification and with the classification suggested by Sartori et al. (2005) to observed precipitation events in order to estimate excess rainfall and peak flow which was obtained with the triangular unit hydrograph of the SCS and with the mean unit hydrograph representing Ribeirão dos Marins watershed, in the municipality of Piracicaba, São Paulo, Brazil, with an area close to 21.87 RBRH – Revista Brasileira de Recursos Hídricos Volume 10 n.4 Out/Dez 2005, 19-29 29 km. The simulated results using two hydrologic soil classifications were compared to the events observed in the watershed. From the comparisons made it was observed that a better result was obtained with the hydrologic classification suggested by Sartori et al. (2005) and with the representative unit hydrograph of the watershed. These results indicate that the hydrologic soil classification suggested by Sartori et al. (2005) is more appropriate for the soil conditions in the watershed studied and that the unit hydrograph of the SCS tends to overestimate peak flow