Mapeamento de áreas susceptíveis à inundação na bacia hidrográfica do rio Umbelúzi-Moçambique aplicando o modelo Hand

Abstract

Natural disasters are intensifying due to climate change, resulting in global human, economic, and environmental losses (IPCC, 2021). Mozambique is one of the most affected African countries, frequently experiencing floods that destroy infrastructure, spread diseases, and displace species. The Umbeluzi basin is particularly vulnerable to floods caused by excessive rainfall and tropical cyclones, with catastrophic events recorded in 1972, 1974, 1966 (Cyclone Claude), 1984 (Cyclone Demoína), and 2000 (Cyclone Glória), (ARA-Sul,2016) This work aims to map areas susceptible to flooding in the Mozambique part of the Umbeluzi river basin applying the HAND model. The images were acquired through the official portal of the United States Geological Survey (https://earthexplorer.usgs.gov/), from where a Landsat 8 image (30/07/2023), to generate the land cover and use map of the region and SRTM DEM (2014), to generate altimetry, slope, drainage network and the HAND model map. The occupied area in the Boane stripin the Umbeluzi river basin isa flood risk zone indicating a clear sign of the influence of disorderly occupation of low-standard urban occupation in riverside areas and the misuse of land. Flood susceptibility classification based on the HAND model distinguishes zones with low, medium, and high susceptibility. The most flood-prone areas are near water bodies, such as in Boane and parts of Namaacha, with a susceptibility distance of up to 3.02 km from the main river. The “occupied zone” (Boane, Moamba, and parts of Namaacha) represents areas of medium to high flood susceptibility, aligning with the areas identified by the HAND model. These susceptible areas often coincide with the proximity to drainage networks, which follow a dendritic pattern characterized by low drainage density and branching.