Distributed Analysis of Curve Number Values in Fifteen Countries Using Different Rainfall-Runoff Methods

Código

XXV-SBRH1161

Autores

Abderraman Róger Amorim Brandão, Maria Clara Fava, Marcos Roberto Benso, Luis Eduardo Bertotto, Paulo Berardo Pessoa de Souza Filho, Juliana dos Santos Poloni, Dimaghi Schwamback, Jullian Souza Sone, Jose Gescilam Sousa Mota Uchoa, Edson Cezar Wendland, Paulo Tarso Sanches de Oliveira

Tema

25 - Processos Hidrológicos

Resumo

The Curve Number (CN) is the most widely used parameter to describe the runoff capacity. However, the original method was developed in the United States considering conditions specific to this country. Moreover, in some countries, there are few studies on the CN assuming stationary land use and occupation and no consensus regarding the choice of abstraction index values in different regions. This study aimed to analyze the distribution of CN values across countries with diverse watershed characteristics. We considered two initial abstraction values (0.05 and 0.02) for precipitation events exceeding 25.4 mm and evaluated three CN calculation methods: asymptotic, median, and least squares. The analysis encompassed multiple countries, revealing significant variability in CN values within each country. Our results demonstrated that antecedent soil moisture conditions had a substantial influence on CN. The asymptotic method yielded higher average CN values, and an initial abstraction value of 0.2 resulted in larger CN values compared with 0.05, which was expected. Several watersheds worldwide are yet to be calibrated, and this paper contribute to a better understanding of local methods and conditions affecting runoff generation.