Morphometric analysis of the Arroio Dilúvio River Basin, Porto Alegre (RS): A comparative study between original and anthropogenic morphology

Abstract

This study analyzes anthropogenic hydrogeomorphological changes in the Arroio Dilúvio River Basin, Porto Alegre, Rio Grande do Sul, Brazil. The main goal is to identify and analyze alterations in the hydrographic network caused by urbanization, utilizing geoprocessing and morphometric analysis. The methodology included collecting historical data, scanning and georeferencing, using Geographic Information Systems (GIS) tools, particularly ArcGIS Pro software to model the Digital Terrain Models (DTM), hydrological modeling, interpretation of aerial photographs and satellite imagery, vectorization, and thematic map production. The results are presented as maps that allow a comparative analysis between the original and anthropogenic situations. They reveal that approximately one-third of the watercourses have been altered by rectification or culverting in recent decades, demonstrating a significant decrease in the main channel's sinuosity and a reduction of 5.39 km in the total length of the Arroio Dilúvio due to channel straightening. Changes in the relief, such as landfill construction and the straightening and culverting of rivers, modified the basin's morphology and have induced geomorphological and hydrological processes, affecting infiltration, surface runoff, subsurface flow, and groundwater flow. This study contributes to understanding the effects of urbanization on the natural environment and provides subsidies for public policies concerning territorial planning and sustainable water resource management in the face of emerging climate change.