Mathematical Modelling Support to the Pdmat-3 Study for São Paulo (PAP014736)

Código

PAP014736

Autores

Marco Antonio Corrêa, José Rodolfo Scarati Martins, Geert F. Prinsen, EDUARDO AYRES YASSUDA, Adri Verwey

Tema

Flood risk management in mega cities

Resumo

São Paulo is a typical example of a fast growing city where the development of the primary drainage system has not kept pace with the increased runoff from the newly urbanized areas. Recently, the third Drainage Master Plan (PDMAT-3) for the Upper Tietê Basin has been completed. Although during the past few years many detention basins have been built and drainage channel capacities have been increased, persistent flooding occurs, primarily on the roads and highways along the main drainage routes. This leads to significant economic losses, primarily due to the interruption of transport. For the first time in the sequence of studies a fully integrated numerical simulation model was developed and applied, based upon Deltares' modelling system SOBEK. The model consists of the following components: (1) rainfall runoff models for 100 up to 400 subcatchments (depending on the discretization level applied), using the SOBEK linear urban runoff and SCS concepts; (2) 1D models for the principal rivers and drainage channels; (3) Real time control (RTC) module for the control of weirs, gates and reservoirs; and (4) overland flow (2D), implicitly connected to the 1D schematization. The SOBEK model covers a catchment area of 5.700 km2 with an urbanized area of 2300 km2 and a population of approximately 19 million. The model has been developed in three discretization levels, where more refinements were progressively introduced, based upon additional data collection. The paper addresses a state-of-the-art method with which rainfall data were generated for the calibration and validation events. Rainfall measured at 111 ground stations were used to calibrate the spatial distribution provided by instantaneous radar images. Processing of the rainfall data was based upon the Delft-FEWS system of Deltares, where the rainfall on each individual catchment could be estimated more precisely than on the basis of the ground stations alone. The paper also addresses the calibration and validation procedure, various application issues, as well as some practical problems that were encountered during the development of the model and the way in which these were overcome.