Segurança hídrica na bacia hidrográfica do rio Paraopeba

Abstract

Access to safe drinking water for everyone is a challenge, especially when considering population growth, land use and cover changes and possible impacts on the local hydrological responses. Considering the Sustainable Development Goals (SDGs), little has been studied about the impacts of land use and land cover and the projections for increased water consumption for the public supply of the population estimated for the year 2030, in the Paraopeba River basin (PRB). The PRB is a tributary of the São Francisco River and contributes to water supply in the Belo Horizonte metropolitan region. The objective of this study was to evaluate water security in the Paraopeba River basin considering water consumption in the region and the impacts caused by changes in land use and cover. The performance of the MHD–INPE hydrological model was evaluated at PRB from 1985 to 2018. The MHD-INPE was used to verify water availability considering different scenarios. Six scenarios were developed. The current scenario (CA) considers the evolution of land use and land cover change over time (1985 to 2018) and the average consumption for the average population supplied by 2018. Scenario C1 uses only the land use and land cover map from 1985 and water consumption for public supply of the estimated population for the same year, considering average per capita consumption until 2018 and the maintenance distribution losses. Four scenarios consider the increase in water consumption to supply the population projected for 2030 (C2, C3, C4 and C5). In these four scenarios, combinations of consumption (maximum and average) with distribution losses (maintenance and reduction) are considered. Compared to the current scenario (CA), in scenario C1 there is an increase in evapotranspiration and canopy evaporation in six of the seven sub-basins. There is also an increase in minimum flows. For the scenarios with increased water consumption (C2, C3, C4 and C5), there is a reduction in minimum flows. According to the simulations, target 6.1 of the sixth SDG, which relates to universal access to water in terms of quantitative aspects, will be met. Among the water consumption scenarios, the one with average consumption and reduction of losses in the distribution system was the one that presented the best results. In other words, smaller reductions in water availability. In addition, these scenarios impacted electricity generation. For scenario C1, there would be a reduction in failures and an increase in electrical energy generation. For scenario C1, there would be a reduction in failures and an increase in electrical energy generation. For water consumption scenarios, the opposite occurs. There was a reduction in estimated electrical energy generation and in the useful volume stored in the Retiro Baixo Hydroelectric Plant reservoir, with a consequent increase in failures.