Identification of Urban Areas Flooded by the Evaluation of Variable Areas of Afluence

The frequency of urban flood events denotes that a pattern of rational urban occupation is of particular importance in flooding events on those areas. This research proposes an approach based on radar images to identify the variable areas of affluence (AVA) in urban watersheds of Uberlandia and its influence on the superficial runoff. AVA represent the flow dynamics of small areas in the basin and their behavior during precipitation events and how it affects the flow in urban basins, as they can suffer variations in shape according to the frequency, intensity and the interval between raining events. This makes it difficult to delimit these areas and, for this study, radar images from Shuttle Radar Topography Mission (SRTM) and 1: 25,000 digital elevation models were used to calculate the Topographic Wetness Index (TWI) associated with the model Height Above Drain (HAND). The results were compared with the TAUDEM flow accumulation model to identify changes in discharge concentration and AVA. The results of the study show a variation of 15% to 21% of the value of the areas for the urban basins evaluated in the city of Uberlandia. This indicates that the assessment of the spatial variability of satellite radar images can serve to delineate the AVA and indicate the potential of occupation in urban basins in order to prevent floods by defining them as special zones in the master plans