Avaliação dos impactos de rompimento da barragem Santa Teresa, microbacia do Rio Quixudi, na área urbana do município de Soledade-PB.

Abstract

The construction of water containment dams is a technique that has been refined over centuries, adapting to different uses and benefiting from experience gained through studies on dam failures. Accidents associated with dam collapses have been documented since their systematic construction became common, with the main observed causes including overtopping, internal erosion, and foundation failures. In the Taperoá River sub-basin, in the state of Paraíba, the Quixudi River micro-basin contains two main reservoirs that experienced a sequential failure in 1985: the Tapuio Reservoir and the Santa Teresa Dam. These reservoirs are located in a temporary river stretch, classified by the National Water and Basic Sanitation Agency (ANA) as flood-prone. However, only the Tapuio Reservoir is monitored by the Executive Water Management Agency of the State of Paraíba (AESA-PB) and is classified as high risk. The Santa Teresa Dam, which receives the outflow from the Tapuio Reservoir, is situated approximately 3 km from the urban area of the municipality of Soledade, where the Quixudi River flows through five neighborhoods. This thesis assessed the impact of the Santa Teresa Dam failure in the downstream valley, considering the flood susceptibility of this river stretch. To achieve this, the study analyzed the physical attributes (hydromorphological and environmental) that influence flood susceptibility and performed a hydrodynamic modeling of the dam failure. Additionally, the dam was classified according to the Risk Category (CRI) and the Associated Potential Damage (DPA). The hydromorphological and environmental characterization, as well as the hydrodynamic modeling, were conducted through the processing of remote sensing data in Geographic Information Systems (GIS). The open-source software HEC-HMS (for watershed delineation), QGIS (for mapping), and HEC-RAS (for hydrodynamic modeling) were used. The dam classification followed the guidelines of CONAMA Resolution No. 143. The results indicated a highly anthropized watershed, with extensive pasture and urbanized areas influencing its flood susceptibility in various ways, with extreme weather events being the main conditioning factors rather than the watershed’s morphology. The hydrodynamic modeling revealed a flood extent affecting 118 buildings, mostly residential, distributed across five neighborhoods in the municipality of Soledade. Some of these buildings remained submerged for up to 15 hours, with water depths exceeding 2 meters. The number of affected people was recorded as 192 individuals, distributed among 60 families, with the majority being adults aged between 30 and 59 years. The dam risk classification indicated a medium-risk category, while the associated potential damage was considered high due to the predominance of residential areas in the affected urban region, increasing the risk of loss of human lives.