Aplicação do modelo height above the nearest drainage (hand) para análise de inundação na Bacia Hidrográfica do Rio Cuiá, João Pessoa, Paraíba, Brasil

Abstract

In recent decades, the number of people experiencing flood damage and losses has increased considerably as a result of unbridled population growth, mismanagement of water resources and drainage systems, therefore causing social, economic and environmental damage. With the advent of new technologies, Unmanned Aerial Vehicles (UAVs) are capable of generating High Resolution Digital Models, an indispensable tool for the formulation of hydrological models, increasingly used in the forecasting and prevention of flood events. One such model is HAND, an algorithm developed by National Institute of Space Research (INPE) that normalizes the drainage network, making it the topographic reference point and which will indicate areas flooded from historical events, that is, the closer a site is to a channel and the lower the altimetric difference between them, the more prone it will be to flood. A section of the Cuiá river basin, located in the county of João Pessoa, was selected as the study area and presents critical flood points in this region. Based on UAV flights, the Digital Terrain Model (DTM) was processed, input data for the HAND model formulation and, from this corrected model and the accumulated area, the threshold of the drainage area of the region from local drainage. Through informal conversations and visits to the study area, flood points were collected in the residences before dredging in the river, necessary for model representation. As a result, the analysis of the flood areas before and after the dredging was done. In the first simulation, before the dredging, the flood points collected in the place were flooded, being able to predict the flood of the region; in the second simulation, after the dredging, the flooded points were not reached by the elevation of the river, showing that the dredging was efficient for these points, but did not prevent points closer to the river being affected. In addition, residences installed within the permanent preservation area range were affected by flood simulations. Thus, the study was able to predict the flood area in a section of the Cuiá river, recommending a greater supervision of municipal Civil Defense in the area, as well as environmental education work with the residents to live harmoniously with the river.