Abstract In Brazil, there are about 2.5 million tubular wells in which 88% of them are illegal, extracting more than 17,580 Mm3/yr. This irregular use may cause sustainability issues that may be economic, social, or environmental (overexploitation, well losses and associated increases of water conflicts; aquifer contamination; and land subsidence). This paper aims to address the illegal wells in Brazil and discuss measures to minimize it. Conclusions indicate that users do not understand the aquifer dynamic and, therefore, do not have a proper understanding of problems such as loss of water quality and quantity caused by the excess of groundwater exploitation. This creates a false idea that there are no water conflicts among users, which causes a lack of engagement by society. Without groundwater users and stakeholder pressure, the government does not aim to control or close illegal wells, and the “vicious cycle” persists. The one way to break this “vicious cycle” would be programs of social communication and users’ participation, coupled with improvements to the control apparatus and inspection from State institutions, making sure that there is correct management and not only legislations that are not applied.

Abstract Urban centers radically alter hydrological cycles, causing unintended consequences for the environment, such as the creation of extensive contamination plumes in unconfined aquifers. The Environmental Agency of the State of São Paulo has observed this issue since 1994. Therefore, this study aimed to create a method using nitrate as an indicator of contamination that permits an assertive interpretation of changes in the groundwater quality in monitoring wells of regional networks. The method was applied in ten cities with monitoring wells in the Bauru Aquifer System. The results correlated the presence of nitrate with the time and dynamics of land use in the capture zones of the wells over 54 years (1962-2016). In areas with sewer networks installed before 2001 and urban occupation greater than 60% of urban occupation in the capture zones, there was an increase in nitrate concentration of at least 35%. Likewise, extending this new method to other wells will make it possible to identify the causes of nitrate and other contaminants in the groundwater-monitoring network in the State of São Paulo.

Águas subterrâneas têm um papel estratégico em tempos de mudanças climáticas, principalmente porque os aquíferos podem fornecer água por longos períodos, mesmo durante a seca estiagem muito longa e severa. A redução e / ou alterações no padrão de precipitação pode diminuir a recarga principalmente no aquífero freático, causando restrição de águas subterrâneas disponíveis. O impacto esperado das alterações climáticas de longo prazo sobre os aquíferos brasileiros para 2050 vai levar a uma severa redução em 70% da recarga nos aquíferos da região Nordeste (comparando aos valores de 2010), variando de 30% a 70% na região Norte. Os dados referentes às regiões Sul e Sudeste são mais favoráveis, com um aumento nos valores de recarga relativa de 30% a 100%. Outro impacto esperado é o aumento da demanda e a diminuição na disponibilidade de água de superfície que vai fazer a população voltar-se para os aquíferos como sua principal fonte de água para uso público ou privado em muitas regiões do país. Assim, um uso integrado de águas superficiais e subterrâneas deve ser considerado no planejamento do uso da água. A solução da escassez de água é baseada em três fatores: O aumento de conscientização da sociedade, um melhor conhecimento das características hidráulicas e químicas dos aquíferos hidráulicos e químicos e ações eficazes de gestão.

Groundwater has a strategic role in times of climate change mainly because aquifers can provide water for long periods, even during very long and severe drought. The reduction and/or changes on the precipitation pattern can diminish the recharge mainly in unconfined aquifer, causing available groundwater restriction. The expected impact of long-term climate changes on the Brazilian aquifers for 2050 will lead to a severe reduction in 70% of recharge in the Northeast region aquifers (comparing to 2010 values), varying from 30% to 70% in the North region. Data referring to the South and Southeast regions are more favorable, with an increase in the relative recharge values from 30% to 100%. Another expected impact is the increase in demand and the decrease in the surface water availability that will make the population turn to aquifers as its main source of water for public or private uses in many regions of the country. Thus, an integrated use of surface and groundwater must therefore be considered in the water use planning. The solution of water scarcity is based on three factors: society growth awareness, better knowledge on the characteristics of hydraulic and chemical aquifers and effective management actions.