Uso do modelo Height Above the Nearest Drainage (HAND) para geração de manchas de inundação em dois pontos da Bacia Hidrográfica Do Rio Vacacaí no Rio Grande do Sul/RS

• Ano de defesa: 2024
• Autor(a) principal: Dimpério, Paola Liberalesso
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; Engenharia Agrícola; UFSM; Programa de Pós-Graduação em Engenharia Agrícola; Centro de Ciências Rurais
• Palavras-chave em Português: Inundação; Rio grande do Sul; HAND; Flooding; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA
• Link de acesso: http://repositorio.ufsm.br/handle/1/34169

The increase in the frequency and intensity of extreme events has caused concern in recent years. Associated with climate change, flooding events in Rio Grande do Sul have caused major damage to the state and the population in general. GIS tools associated with hydrological models have helped to assess the impacts generated and even predict events. Based on this, this work evaluates the use of the Height Above the Nearest Drainage (HAND) model, which is a hydrological model that normalizes a Digital Elevation Model (DEM) based on the vertical distances relative to the nearest surface flow, where it is possible to generate flood patches after reclassifying the normalized DEM. HAND was used to generate flood spots at two points in the Vacacaí River basin, at station 85470000 located in São Gabriel and station 85600000 located in Passo das Tunas in Restinga Seca in Rio Grande do Sul using two types of input data, the SRTM mission's DEM and ANADEM's MDT prepared by the Hydraulic Research Institute (IPH) in partnership with the National Water Agency (ANA). In addition, the thresholds for the density of the drainage network were 5000, 10000, 25000 and 30000 for the 85470000 station and 5000, 35000, 50000 and 65000 for the 85600000 station. Validation was carried out by comparing the patches generated by HAND with reference patches from the Sentiel-2 MSI images for April 30, 2022 for the 85470000 station and May 6, 2024 for the 85600000 station. Two methods were used to extract the water patch, the maximum likelihood supervised classification method (MAXVER) and the Modification Normalized Difference Water Index (MNDWI). The thresholds that reached the best values were 25000 for station 85470000 and 65000 for station 85600000. The MDE SRTM adjusted best to both locations. The results showed a good Kappa index value, however the model overestimated the flooded area at São Gabriel station.