ANÁLISE DA EFICIÊNCIA DO DIQUE DE CRUZ DO ESPÍRITO SANTO (PB) POR MEIO DO MODELO HAND

Abstract

Many Brazilian cities are constantly affected by floods, mainly due to the lack of proper urban planning. Therefore, flood risk management plans apply structural measures, such as hard engineering structures and non-structural measures, such as mapping of areas that are more susceptible to flooding. The main goal of this work is to evaluate the efficiency of the Cruz do Espírito Santo dike in Paraíba, which was built to protect the city from flooding. The urban core of Cruz do Espírito Santo is located on the banks of the Paraíba River and there are several historical records of flood events in the city over the last few centuries. To assess the efficiency of the dike, flood susceptibility maps were generated using the HAND (Height Above the Nearest Drainage) model. The flood maps were generated from Digital Terrain Models with a spatial resolution of 27 centimetres of the study area, which includes the city of Cruz do Espírito Santo and a section of the Paraíba River. Two Digital Terrain Models were generated: one that maintained the dike structure and another that removed the dike structure through the Agisoft PhotoScan photogrammetric processing software. From the comparison of the flood maps generated for the two situations, it can be concluded that the dike would have protected the city from the flood event occurred in 1985, if it was already built at that time. This study approaches a little explored functionality of the HAND model: the analysis of the efficiency of physical structures through HAND flood maps