Evaluación del riesgo por inundación en calles de una cuenca urbana de alta pendiente del centro de Misiones

Abstract

The progress of urbanization on the Paranaense rainforest –located in the Central Highlands (Sierra Central) area within the province of Misiones– occurred during these last years has recently started to highlight the need of a comprehensive study on the hydrological response of such anthropized systems. Given that natural conditions of this area (i.e. vegetation cover, soil type, ground elevation) have so far minimized the impacts of flooding, little interest was being put on urban hydrology. Urbanization has changed the natural conditions of surface runoff, increasing the risk of flooding in cities, with the occurrence of higher water levels and faster velocities of flow over the streets. This work focuses on the assessment of the dynamics of surface runoff on the streets within the basin of the Mbotaby stream, in the city of Oberá, Misiones. The identification of maximum water levels and flow velocities on street-ditches within the basin was achieved with the aid of the setting up of a hydrological-hydraulic model, using the SWMM 5.0vE environment onto a number of recurrences. Maps of maximum water levels and flow velocities were developed using rainfall events related to 2, 5 and 100 years of recurrence. Flooding areas over street-ditches were located and quantified for each one of the hydrological events; areas with different flow velocities were identified as well. Finally, threatened areas were detected due to the combination of overflowing water levels and high velocities within the basin.