A Strategy for Calibration and Validation of a Physically Based Distributed Hydrological Model in Tropical Catchments: Case Study of São Paulo, Brazil

Hydrological modeling is an important tool for water resources planning, and calibration and validation are one of the main steps for the right use of models. The intrinsic characteristics of the tropical region, such as temperature, precipitation and soils, require special attention in the modeling processes to increase simulation accuracy of physically based distributed models. In this paper we describe and analyze calibration and validation steps of these models to understand the challenges of hydrological modeling in the tropical region. A catchment located in the tropical region was used for the calibration and validation of a physically based distributed hydrological model (Mike SHE). The results showed that the saturated zone has a fundamental role in the hydrological responses, mainly for the minimum flow simulations; however, the land use parameters results in low influence on the annual flow. Adjustments of maximum flow in tropical regions seem to be more influenced by intensity of precipitation. Therefore, the results suggest that the strategy of fitting the base flow followed by the adjustment of the maximum flow and the evapotranspiration and transpiration processes is an efficient procedure to calibrate the model.