ANALYSIS OF COMPENSATORY TECHNIQUES IN MITIGATING URBAN FLOODS IN A TROPICAL CLIMATE BASIN ON A FIXED DUNE IN THE COAST OF NORTHEAST BRAZIL
Urban flood; Hazard; LID; Fixed Dune; Tropical.
The surface impermeabilization due to urbanization alters the hydrological regime and natural water flows in cities, bringing consequently, an increase of flood risk with the potential to cause damage to the health of the population and property. For this reason, an assessment of the risk of urban flooding has been applied in the sustainable management of urban drainage. The flood risk is commonly assessed by hydrological models, while its mitigation is mainly given by the implementation of urban drainage systems. As an alternative to conventional systems based on canalization, implemented in most urban basins, low impact development techniques (LIDs) are considered effective solutions to reduce floods and have been widely used. However, the performance of these structures when deployed in a decentralized way is not yet fully known, especially in tropical climates with the occurrence of concentrated rainfall. Thus, the present work aims to evaluate the performance of LIDs to mitigate the hazard of urban floods, associated with the conventional drainage system existing in an urbanized basin on a fixed dune and with a tropical climate. The study will be developed in a sub-basin in the city of Natal/RN using integrated modeling of runoff with the Personal Computer Storm Water Management Model (PCSWMM) in 18 scenarios for the implementation of LIDs (green roofs, permeable pavement, infiltration trenches, bioretention cells and rain barrel). With the flood-prone areas of the basin in each scenario, the mitigation of the flood risk at critical points in the selected sub-basin will be evaluated. Three hazard levels (low, medium and high), previously determined based on the depth and flow velocity metrics, will be used. Thus, it is expected that the flood mitigation obtained in each of the LID scenarios will support decision making as the most efficient alternative in flood hazard mitigation.