Multilayer modelling as a support tool for flood diagnosis and drainage system design

Abstract

The use of dual-drainage models has increased in recent decades, mostly because of advances in mathematical methods and geographic information system tools. This type of modelling provides precise diagnoses and can be applied to evaluate stormwater infrastructure and diverse drainage alternatives. Minor and major drainage relations in the Dona Eugênia watershed, Brazil, were analysed in this study. Three alternatives simulated the quasi-two-dimensional hydrodynamic model Modcel. The first alternative considered only the terrain surface layer, representing the current situation. In the second alternative, a layer containing a designed storm sewer was introduced. Considering the previous alternatives as a way to diagnose the main minor and major deficiencies, a third alternative was formulated considering previous projects to solve floods in the watershed, incorporating them in the second alternative with functional minor drainage. The results identified the locations of minor drainage gaps, thus helping to direct efforts to the most critical regions, optimise operations and minimise maintenance costs. The results could also be used to evaluate the effects of storm sewer network discharges in major drainage systems, leading to better design of the drainage infrastructure. The major drainage itself can be optimised, once its responsibility in flooding is identified.