Diagnóstico de canais fluviais em torno de infraestruturas de sistemas hídricos nos lagos Igapó, Londrina, Paraná: análise dos impactos ambientais

Abstract

The interaction between human occupation and natural processes is fundamental to understanding the environmental transformations that occur in a watershed. Monitoring land use over time is vital to analyze the changes resulting from anthropic actions in urban watersheds, whether they be constructions that alter the natural course of urban river channels, such as dams, or changes in surface runoff and soil infiltration in the basin. In Londrina, where the population grew rapidly in the 20th century, and more specifically in the Igapó lakes, where several hydraulic constructions were made, it becomes clear the need to analyze and mitigate urban pressure, as well as periodically evaluate the functioning of these structures. Therefore, the objective of this study was to analyze the river channels of the Igapó lakes in Londrina, Paraná, and the water system infrastructures that compose it, aiming to diagnose the impacts caused by the urbanization process of the basin. The research was carried out in two stages. The first focused on diagnosing the watersheds of the Igapó lakes, divided into three sub stages: analysis of land use and occupation from 1959 to 2022, hydrological characterization, and characterization of the hydraulic structure components. The second stage aimed to evaluate the Igapó lakes by applying protocols at 10 points: the Rapid Assessment Protocol for Urban Rivers (PARu) and the Stability Protocol based on hydraulic structures. In the land use and occupation analysis, it was found that Londrina's master plans allowed for commercial, industrial, and residential use in this area, and it was mapped that the watersheds were predominantly rural in 1959, reaching approximately 80% urbanization by 2022.The hydrological characterization results of the Igapó lakes watersheds showed increases in maximum flows ranging from 55.11% to 123.84%. Regarding the hydraulic structures present in the Igapó lakes, seven culverts were identified, of which two culverts are built in disagreement with DNIT standards, and it was observed that some structures do not support the maximum flows calculated for 2022. The PARu results indicated classifications ranging between "good" and "fair," while the points evaluated in the Stability Protocol based on the hydraulic structures were classified as "good". Based on the analysis of the results, it is concluded that the advancement of urbanization in these watersheds caused hydrological changes that, in turn, overloaded some structures, causing their malfunction.