Proposta metodológica para diagnóstico do metabolismo da água em bacias urbanas

Abstract

The 2030 Agenda presented by the United Nations, proposes objectives to achieve sustainable development, including SDGs 6 and 13, which portray the guarantee of availability and sustainable management of water, increased efficient use of water resources, in addition to of actions against global climate change, which can intensify water scarcity or floods. Furthermore, the impact of population growth and economic growth in cities, associated with climate change, need to be evaluated in relation to water use and how its effects on hydrological events can affect the Integrated Management of Water Resources. Given the possibility of analyzing sustainability and water security in the urban environment through the association of water balance with urban water metabolism, a methodological proposal applied to urban basins was structured and presented as a research product, based on the methodology, results and conclusions used in a case study carried out in a city, the methodological structure is based on the precepts of urban water metabolism, through the determination of inflows, outflows and water stocks in an urban perimeter, through the use of the STAN software version 2.6.801, applied in the analysis of material flows, associated with the use of the QGIS software version 3.10, in the identification of the basins, sub-basins and in the estimates of permeable and impermeable areas. Bearing in mind the municipality of Alagoinhas/BA as the focus for the case study and development of the proposal, the elaboration of the necessary database demarcated consultations with the local sanitation concessionaire, environmental agencies, large companies and the search for standards and parameters in the specialized scientific literature. The sources and standards required to quantify water flows and stocks are based on the structuring of the following information: production of raw and treated water, number and category of consumers served by the supply systems, water abstraction grants and effluent discharge with respective flows, coverage of the sewage collection and treatment system, volumes treated and/or released, coverage of drainage systems, indication of permeable and impermeable areas, in addition to precipitation data. Based on urban metabolism, it is observed that in 2019, the volume of water extracted, just for the city's supply, was equivalent to about 46.23% of the renewable underground water reserve. Of the entire volume of water that enters the system, 42.41% is consumed by the city for residential, industrial, commercial, public, philanthropic uses, however, only 32.03% of the total effluents generated are treated and 34.20% infiltrated into the soil. The methodological proposal, product of the research presented in full in the results chapter, based on the analysis of material flow incorporated into the water balance, allows detailing the flows, stocks and processes resulting from the integration between the natural environment and human actions, contributing to the management of water, through the mapping of strengths, weaknesses and identification of options for the maintenance and use of water in circulation in the urban area.