Sediment connectivity in a hot and humidity tropical watershed: Contribution to environmental planning and management

Abstract

This study aims to identify and analyze the sediment connectivity in the Duas Bocas River watershed (BHRDB), in the Metropolitan Region of Greater Vitória (RMGV/Brazil), for the year 2019 and simulate an environmental degradation scenario for the watershed. For the modeling of sediment connectivity, a land use and land cover map from 2019 was used, followed by an environmental degradation scenario where the Atlantic Forest was replaced by exposed soil. The digital elevation model has a spatial resolution of 5 × 5m. The Index of Connectivity (IC) for the year 2019 ranged from −11.32 to 0.49, with lower values in the upper portion of the watershed, which is protected by the Atlantic Forest vegetation, minimizing the possibility of sediment production and transfer to the river. Regarding the environmental degradation scenario, the IC ranged from −11.32 to 1.68, with the highest IC occurring in the area of exposed soil in the upper portion of the watershed that was previously protected by the Atlantic Forest. It was also found that the estimation of IC is sensitive to the spatial resolution of the digital elevation model, making it challenging to assess the plain area near the outlet of BHRDB. The geospatial variability of sediment connectivity highlighted the importance of maintaining forests in headwater areas in relation to soil degradation in tropical environments. The IC proved to be an important tool for developing environmental scenarios, contributing to the management and environmental planning of watershed.