Optimization for control of urban flooding: application in the Vila Isabel hidrographic Basin/Viamão/RS

Abstract

The rapid and uncontrolled urbanization, especially in developing countries, has led to significant impacts on both the environment and people themselves. The existence of highly impermeable areas brings as consequence the increase in surface runoff volume, causing an increase in peak flows up to ten times the pre-urbanization flow. This requires thus, the need of alternatives to solve or reduce the problems related to the increased volume disposed, and not only transferring it to another location. In this context, the Best Management Practices (BMPs) can be implemented, which are measures for managing storm water in urban areas as, for example, the detention reservoirs. Thus, this work aims to develop a methodoly to evaluate the hydrological impact minimization of an urbanized basin, so that it can behave hydrologically similar to pre-urbanization conditions, analyzing deployment costs of detention basins to prevent flooding downstream. Hence, a hydrologic simulation model with IPHS1 has been used to determine the studied basin tributaries output hydrographs. The study area represents the Santa Isabel watershed, known Mãe D’água watershed, with 3,39 km², located in Viamão/RS. The results showed that the application of an optimization technique associated with a hydrological model has proven to be useful in storm water runoff control projects costs evaluation (detention basins) for the urban study area. Moreover, even without the availability of observed hydrological data and detailed information about the process of urbanization in the study area, it was possible, through the application of the presented methodology, to develop scenarios for analyzing the urban zone expansion and quantification of hydrological impact, in order to minimize the identified problem.