Integração de geotecnologias e análise hidrogeotécnica na segurança de barragem de um lago urbano sob eventos pluviométricos

Abstract

This research evaluated the safety of the barrage of the Municipal Lake of Toledo, Paraná, by means of the integration of geotechnologies and hydrogeotechnical monitoring, considering the influence of two pluviometric events on the hydrological dynamics of the microbacia of Sanga Panambi. The study was structured in two complementary studies. Initially, an integrated topobatimetric characterization of the Municipal Lake and Sanga Panambi was carried out, using surveys with GNSS RTK, ecobathmeter, unmanned aerial vehicle and geoprocessing tools, aiming to represent the morphology, or relay and armament capacity of two water bodies. Subsequently, hydrogeotechnical monitoring of the barrage was carried out, with records of precipitation, linimetric levels, phreatic line by half of piezometers and vacuums in the lake in Sanga Panambi, integrated by statistical and spatial analyses. The topobathymetric results will allow identifying flat areas, transition zones, deep depressions and assessment patterns, in addition to estimating normal volume of 49,759.69 m³ and maximum volume of 143,157.86 m³ for the Municipal Lake. The difference between the scenarios shows the regulatory function of the reservoir in the damping of pressure peaks. The hydrogeotechnical monitoring demonstrates a consistent relationship between precipitation events, elevation of the reservoir levels, increase in current vazões and temporary alterations in the piezometric conditions of the mass. The water located in the lake presents a lower amplitude of variation, while the points located in Sanga Panambi will respond more quickly and intensely to the rainwater. Despite the sensitivity of the structure to rainfall events, no critical conditions of geotechnical instability or compromise of hydraulic performance have been identified during the monitored period. It is concluded that the integration between geotechnologies and pluviometric, linimetric, fluviometric and piezometric data constitutes an efficient approach to characterize urban water systems, assess cliffs and support the monitoring of barrage security. The results provide technical subsidies for urban and environmental planning, cliff management, development and updating of barrage safety instruments and adoption of preventive measures in urban areas subject to hydrological variability.