Dinâmica da qualidade da água e proposta de manejo de um sistema hídrico em um parque urbano

Abstract

Urban expansion, driven by population growth, requires effective planning to ensure quality of life and environmental preservation, especially in relation to water resources. Urban planning laws play a fundamental role in regulating this process, considering environmental, social and economic aspects. The lack of adequate planning results in disorderly urbanization, characterized by irregular occupations and insufficient infrastructure, causing serious problems, including the degradation of water resources. This study aims to evaluate the limnological dynamics of the water system in the Bernardo Berneck Municipal Ecological Center for Recreation and Leisure, in Várzea Grande - MT, in addition to proposing a management of the aquatic ecosystem to reduce the nutrient load and control the proliferation of macrophytes. The region faces accelerated growth, which aggravates problems such as the lack of basic sanitation and social inequality, in a context of deficient urban planning. The methodology used included the implementation of five water sampling campaigns, distributed during rainy and dry seasons, and two sediment collections. The bathymetric survey was conducted using an ADCP and a GPS to collect water level data. Water collections followed specific standards, with analysis of physical, chemical and microbiological parameters in an accredited laboratory. Data on precipitation and flow were monitored to understand the dynamics of the water system. The data obtained were subjected to statistical analyses, such as tests to compare averages between periods and locations, in addition to cluster analyses to group the sampling points. The results of this study revealed high concentrations of ammonia nitrogen and nitrate at the entrance to the water system, with a reduction in the lagoons, although the values are still above the limits established by CONAMA Resolution n. 357/2005. Total phosphorus and orthophosphate also showed maximum levels in lagoon 1, in part due to macrophyte decomposition, which contributes to high BOD levels and low dissolved oxygen (DO) levels, indicating a state of eutrophication. Microbiological analysis demonstrated significant fecal contamination, with total coliforms and E. coli exceeding quality standards, which poses risks to public health. Furthermore, the varied bathymetry and sediment composition proved to be rich in nutrients, impacting the dynamics of water quality and the health of the aquatic ecosystem. These results highlight the need for management and conservation actions in the water system studied.