Modelagem hidrológica da bacia do Rio Marrecas: análise de calibração e validação de paramêtros de vazão de base e perdas no HEC-HMS

Abstract

The Marrecas river basin has a long history of flooding events in its urban stretch within the municipality of Francisco Beltrão – Paraná, necessitating hydrological diagnostic tools for territorial planning and flood mitigation. The primary objective of this study was to develop and conduct a critical analysis of the calibration process of a rainfall-runoff hydrological model for the basin in question using the HEC-HMS software, focusing on the parameters of the Loss and Baseflow methods. The methodology involved configuring a continuous simulation over a two-year period (2022-2024). The model was structured with SCS Curve Number (Loss), Recession (Baseflow), SCS Unit Hydrograph (Transform), and Muskingum-Cunge (Routing) methods. Input data included the Copernicus GLO-30 DEM, Curve Number (CN) data from SNIRH/ANA (2022), and hydrometeorological data from two rain gauge stations and one streamflow gauge station. Calibration results were classified as “Unsatisfactory,” indicating a chronic overestimation of runoff volume, with a persistent Percent Bias (PBIAS) of +57.32%. Diagnostic tests, including the deactivation of the baseflow component, demonstrated that most of the volumetric error originated from the SCS-CN loss method. It was concluded that the SCS-CN method is methodologically inadequate for long-term continuous simulations, as its inability to simulate evapotranspiration (ET) results in an unrealistic water balance, leading to volume overestimation. Additionally, the low density of the rain gauge network was identified as a critical source of input data uncertainty.