Alagamento e inundação urbana: modelo experimental de avaliação de risco

Abstract

This study aimed to develop an experimental model for assessing risk of flooding and flood to Bethlehem, based on the model of digital terrain elevation, the runoff hydrograph and the peak flow of the main drainage channel of the river basin. We used GIS tools to systematize the vector data on the units occupied by buildings, roads and the axis of altimetric quotas to generate a digital terrain model. The development of the system was customized by programming language, aiming to facilitate and simplify the operation of the processing routines of the equations defined for the implementation of the hydrological model. The hydrologic model basin was subdivided into cells of 25m², and each one was given his share of high and calculated their runoff based on the percentage of impermebialização of each. The peak discharge channel was obtained on field trips at two different situations: during rainfall events of high intensity and one without the influence of rain. For these two conditions, it was also evaluated the influence of the tide of the Guamá River on the main channel of the basin. The consistency of the model was found from the sensitivity test performed for each variable used and validated based on data from some rainfall events that was checked by journalistic and photographic records obtained in the field. The results indicate that the applied hydrologic model, and the developed system are efficient and effective to be applied as a tool for risk assessment of flooding and flood.