Modelagem da drenagem urbana e avaliação das cargas bacteriológicas na Vertente Marítima de Fortaleza, Ceará

Abstract

Urban drainage systems can represent sources of pollutants input to the receiving bodies for which they are intended. Therefore, the present work aims to propose a tool for modeling the urban drainage system of the Vertente Marítima basin of Fortaleza, Ceará, aiming at the evaluation of bacteriological loads. For this purpose, the Stormwater Management Model (SWMM) was selected for the hydrological and hydraulic simulations; a methodology for the calculation of bacteriological loads was proposed by estimating the diffuse load [DL] (MPN, day -1 .ha -1 ) and its correlation with a series of hydro-environmental variables and scenarios for different pluviometry precipitation conditions were analyzed, as well as sewage collection and inadequately disposed solid waste (IDSW). The resultsshow that SWMM gives representative results and that the rainy season is responsible for the greater contribution of the bacteriological load to the seafront. Regarding the predictive model, a second-order potential function was adjusted by correlating DL with the average monthly precipitation (mm. day -1 ) for the three sub-basins analyzed. Subsequently, the coefficients of the equations found were correlated to IDSW (kg.day -1 ), obtaining a logarithmic adjustment (R 2 = 0.99), with which it is possible to obtain a DL estimation equation for any sub-basin of Vertente Marítima. An analysis of the scenarios showed a significant increase of the load in extreme precipitations (twice) and a considerable decrease with the increase of the fraction of the population connected to the sewage network and the decrease of IDSW production (0.28 and 0.38 times the initial value in the Jacarecanga and Maceió Stream, respectively).

Coupling Hydrological and Hydrodynamic Models for Assessing the Impact of Water Pollution on Lake Evaporation

“…Changes in the physical state of water, which make up the hydrological cycle, are an important indicator of the environmental characteristics of watersheds. Changes in land use are key factors in the urbanization process [1,2]. In this case, the removal of vegetation cover and soil sealing have been identified as major elements responsible for altering the hydrological cycle [1].…”

“…Several impacts on hydrology can be directly related to unplanned urbanization [2][3][4][5], such as increased peak flow and the decrease in the time of concentration of the basins. In addition, impacts resulting from land use and occupation can directly affect receiving water bodies [6,7].…”

“…Studies related to hydrological-hydraulic modeling and simulation of urban drainage systems are essential for the representation of physical processes in urban watersheds [2,[11][12][13]. Furthermore, computer modeling enables the analysis of various scenarios, optimizing costs and allowing the proposition of mitigating measures [2]. In this way, modeling tools can support decision makers.…”

“…Some have studied the impact of climate on hydrodynamics, including the thermal stratification patterns of lakes [19][20][21][22][23]. Others estimated pollutant loads and modeled water quality in different environments [2,13,24]. Additionally, several studies have coupled hydrological models to hydrodynamic models [21,25,26].…”

“…This would provide a robust tool with relatively low computational effort for the integrated analysis of the interaction between the watershed and the receiving water body, facilitating the understanding of the processes and assessment of the basin's impacts on the water body. It is known that urban watersheds are more subject to intense hydrological variability [2]. This can have a more severe impact on the receiving water bodies, both from the point of view of hydrodynamics and water quality.…”