Resumo A Constituição Federal de 1988 atribuiu aos Estados e ao Distrito Federal um papel de protagonismo na governança das águas subterrâneas, contudo, faltam estudos que avaliem a forma como esses entes conduzem o processo na perspectiva das políticas públicas nacionais. O objetivo deste artigo é identificar as obrigações jurídicas nacionais relacionadas à governança dessas águas e construir uma ferramenta que permita avaliar se elas foram incorporadas e aplicadas pelos Estados. A metodologia utilizada foi a análise documental e a realização de entrevistas. A legislação federal garantiu um standard de mecanismos para a gestão estadual, a partir dos quais foi possível estruturar o Sistema de Avaliação de Governança das Águas Subterrâneas (Sagas), composto por 48 indicadores principais e 25 subordinados. O Sagas é um esforço metodológico que visa criar um indicador jurídico que gere dados comparáveis e sistematizados sobre esse ambiente de governança estadual, permitindo identificar as fragilidades da gestão.

Abstract The 1988 Brazilian Federal Constitution granted a leading role in groundwater governance to the states and the Federal District. However, there are no studies evaluating how these entities conducted this process from a national public policy perspective. The present article aims to identify national legal obligations related to groundwater governance and develop a tool to determine whether the states have appropriately implemented them. Our methodology includes document analysis and interviews. The federal legislation provided standard mechanisms for state management, allowing for structuring a Groundwater Governance Assessment System (SAGAS: the acronym in Portuguese) that comprises 48 primary and 25 secondary indicators. SAGAS is a methodological effort to create a legal indicator to generate comparable and systematized data on states’ environment of governance to help identify management weaknesses.

Resumen La Constitución Federal de 1988 asignó a los Estados y al Distrito Federal un rol protagónico en la gobernanza del agua subterránea, sin embargo, faltan estudios que evalúen como estas entidades conducen ese proceso desde la perspectiva de las políticas federales. Este artículo pretende identificar las obligaciones jurídicas federales relacionadas con la gobernanza de estas aguas y construir una herramienta que permita evaluar si han sido incorporadas y aplicadas por los Estados. La metodología utilizada fue el análisis de documentos y entrevistas. La legislación federal garantizó un estándar de mecanismos de gestión estatal, a partir de los cuales se estructuro el Sistema de Evaluación de la Gobernanza de Aguas Subterráneas (SAGAS), compuesto por 48 indicadores principales y 25 subordinados. SAGAS es un esfuerzo metodológico que idealiza un indicador jurídico que genere datos comparables y sistematizados sobre el ambiente de la gobernanza en los Estados, permitiendo identificar las debilidades de la gestión.

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.

Abstract This study assessed the relationship between the recharge of the unconfined sedimentary Adamantina Aquifer and its discharge into the Batalha River in a small basin of 125 km2 that drains the municipalities of Bauru, Agudos and Piratininga (SP, Brazil). According to the Eckhardt Flow Separation Filters and Soil Moisture Accounting Procedure methods, the recharge was 312.6 mm/yr and 232.0 mm/yr, respectively; and 286.2 mm/yr to the modified-Thornthwaite method for the 2000–2018 period. Recharge values prone to converge as more extended periods are analyzed (ideally 18 years) because the sensitivities to a specific parameter tend to be mitigated over time. With the integration of the methods, we established how changes in land-use impact the aquifer recharge and, thus, the discharges and the behavior of the river’s recession curve. Areas used to cultivate sugar cane (193 mm/yr), eucalyptus (150 mm/yr), or to urbanization (72 mm/yr) exert control over aquifer recharge even more than topography or type of soil. The combined and integrated use of three simple techniques allows them to be used for land-use planning and assessment of water availability in small hydrographic basins when hydrological data are scarce.

ABSTRACT: The integrated analysis of geophysical loggings for identifying transmissive fractures has had a limited use in Brazil, although a large number of studies have been conducted so far throughout the world. The application of those tools has gained a crescent importance as they are needed for characterizing groundwater contamination in fractured rock aquifers at a great number of industrial sites worldwide and in Brazil. This paper presents the analysis of data collected by caliper, optical televiewer (OPTV), acoustic televiewer (ATV) and flowmeter loggings in four deep supply wells located in the industrial area of Jurubatuba, city of São Paulo. Five fracture sets (G1 through G5) were identified based on OPTV and ATV borehole loggings. The main fracture set (G1), NE-striking with low to intermediate dip, is subparallel to the foliation, being at great extent the result of the reactivation of this previous discontinuity. Fractures on ATV and OPTV images were visually classified with regard to flow evidence, and a positive correlation between high flow evidence and significant flow rate, measured by a flowmeter, was identified. On the other hand, the majority of fractures with insignificant, low or intermediate flow evidence are located in depth intervals with no significant flow rate. Fractures that belong to G1 are of major importance for flow, as in 9 of the 16 intervals with significant flow, they are the only fractures present. Data were inconclusive regarding transmissivity of high dip fractures, because few of them were intercepted by the well boreholes. However, there is evidence that subvertical fractures of sets G3 and G5, NE and NW striking, respectively, are also transmissive, which corroborates outcrop observations. Although geophysical loggings are essential to identify the most important segments of boreholes for water input and output, and to collect detailed data of low dip fracture sets at greater depths, the structural geology characterization of fractured aquifers cannot rely on borehole geophysical loggings alone. For proposing realistic conceptual models of the fracture network, data from boreholes should be complemented with data from large rock exposures (quarries), in order to describe geometrical parameters, such as spacing, length, and physical connectivity of low, intermediate and high dip fractures, as well as evidence of flow along individual fractures.

Resumo As águas subterrâneas são um recurso imprescindível para a sociedade e o meio ambiente no Brasil. Mais de 557 m3/s (17.5 km3/a) são extraídos através de 2.5 milhões de poços para atender a demanda nas cidades e no campo, gerando uma economia de R$ 56 bilhões ao ano (US$ 14 bilhões/ano). O aquífero tem função impar no ciclo hidrológico, pois seu gigantesco armazenamento regula a perenidade de rios, lagos e mantém mangues, pântanos e a vegetação em épocas secas. Mais de 24% (média anual) a 49% (período de estiagem) da vazão desses corpos hídricos é mantida pela descarga de aquíferos. Embora os estudos sobre a qualidade de suas águas seja ainda restrita, sabe-se que a maior parte dos aquíferos ainda preserva sua excelente qualidade natural. Mais recentemente, tem-se visto o crescente aumento dos casos de contaminação, associadas a: (i) anomalias naturais geoquímicas (ferro, manganês, flúor e, secundariamente, cromo, bário e arsênico), devido à dissolução de minerais específicos; e (ii) atividades humanas contaminantes, relacionadas a áreas urbanas sem rede de esgoto ou com atividades industriais, armazenamento de produtos perigosos e deposição de resíduos sólidos. Dentre os compostos antrópicos comumente manipulados, os mais problemáticos correspondem aos solventes organoclorados e metais pesados e, para áreas sem rede de esgoto, o nitrato. O precário conhecimento da situação da qualidade dos aquíferos, sobretudo em cidades, demonstra a necessidade de se investir em projetos de pesquisa e mapeamento hidrogeológicos permanentes e sistemáticos, que levem à melhoria das práticas de proteção da qualidade das águas subterrâneas.

Abstract Groundwater is an essential resource for society and the environment in Brazil. More than 557 m3/s (17.5 km3/y) are extracted through 2.5 million wells to meet demand in cities and the countryside, generating an economy of R$ 56 billion per year (US$ 14 billion/year). The aquifer has a remarkable function in the hydrological cycle because its large storage regulates the perenniality of rivers, lakes and preserves mangroves, marshes, and vegetation in dry periods. Aquifer discharges maintain between 24% (annual average) and 49% (dry season) of the flow of these surface water bodies. Although studies on groundwater quality are still restricted, it is known that most aquifers still preserve their excellent natural quality. Nevertheless, over the past years, there has been a growing increase in cases of contamination associated with: (i) natural geochemical anomalies (iron, manganese, and fluorine, secondarily, chromium, and barium, and rarely arsenic) due to the dissolution of specific minerals; and (ii) human contaminant activities, related to urban areas without sewage network, or with industrial activities, storage of hazardous products, and solid waste facilities. Among the anthropic compounds commonly handled, the most problematic are the chlorinated organic solvents and heavy metals, and in non-sewage areas, nitrate. The precarious knowledge of aquifer-quality, especially in cities, demonstrates the need to invest in regular and systematic hydrogeological research and mapping projects that drive to the improvement of the practices on aquifer quality protection.

ABSTRACT Transmissivity is an important hydraulic parameter to determine the amount of water passed horizontally across a given saturated thickness of an aquifer. The techniques to quantify this parameter, such as grain size analyses or pumping tests, can have limitations of time/spatial scale, viability, or economically. One technique that can be used, but little adopted, is the capture zone analysis. In this paper, capture zone analytical equations were used to estimate transmissivity values in order to verify the effectiveness of this methodology as alternative in situations where other traditional methods present implementation difficulties. The results were compared with field data estimated by aquifer tests conducted in the same region. A sensitivity analysis was also performed to identify possible discrepancies between the analytical and field data results. The aquifer studied was the Sete Lagoas Karst Aquifer in the urban region of the municipality of Sete Lagoas, Brazil. The method proved to be a viable and economical tool, where the analytical values compared to the aquifer tests showed similarities, being confirmed by a sensitivity analysis. However, a reliable potentiometric surface map, which enables the identification of the parameters for analytical capture zone equations, is needed.

RESUMO A área de pesquisa localiza-se no Estado de Minas Gerais, Brasil, entre os municípios de Pedro Leopoldo, Matozinhos, Lagoa Santa e Sete Lagoas até os limites do Rio das Velhas como limite oriental. Está inserida no Cráton São Francisco, onde afloram sedimentos argilo-arenosos carbonatados do Grupo Bambuí, na Bacia do São Francisco. Apesar do conhecimento geológico desenvolvido anteriormente, a região carece de um trabalho de integração e detalhamento dessas informações. Por esse motivo, o objetivo principal foi contribuir na qualidade da cartografia geológica, da distribuição espacial e da geometria estrutural. Assim, foram realizados um mapeamento geológico, fotointerpretação e avaliação de 270 perfis litológicos de poços. Foi possível estabelecer uma nova perspectiva geológica da região, com obtenção do mapa geológico detalhado de Sete Lagoas, 14 seções geológicas cruzadas e um modelo geológico conceitual. O estudo mostrou que a área se encontra em um contexto geológico de borda de bacia, apresentando uma geometria condicionada por sistema de horsts e grábens. Essa característica estrutural deslocou sequências estratigráficas posicionando-as lado a lado, com sequências litológicas de idades distintas.

ABSTRACT The study area is located in the state of Minas Gerais, Brazil, among the municipalities of Pedro Leopoldo, Matozinhos, and Sete Lagoas, with Velhas River as the eastern boundary. It is located in the São Francisco Craton, where carbonated argillo-arenaceous sediments are emplaced giving origin to the Bambuí Group, in the São Francisco Basin. Despite the geological knowledge previously developed, the region needs work on integration and detailing of such information. For this reason, the main objective was to contribute to the quality of the geologic cartography, the spatial distribution, and the structural framework geometry. Thus, geologic mapping, aerial photography interpretation, and evaluation of 270 lithologic well profiles were carried out. It was possible to establish a new geologic perspective of the region by obtaining the detailed geologic map of the municipality of Sete Lagoas, 14 geologic cross sections, and a geologic conceptual model. The study showed that the area is within a basin border, presenting a geometry conditioned by horst and graben system controlled by faulting. This structural feature displaced stratigraphic sequences positioning them side by side with lithologic sequences with different ages.

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.

Concentrações anômalas de cromo hexavalente foram detectadas em águas subterrâneas do Aqüífero Adamantina em pelo menos 54 municipalidades localizadas na região noroeste do Estado de São Paulo, sudeste do Brasil, algumas vezes ultrapassando o limite máximo permitido para consumo humano (0,05 mg.L-1). Um estudo foi realizado no município de Urânia, onde as mais elevadas concentrações de cromo da região foram detectadas. A origem da contaminação foi definida como natural, pois foram detectadas concentrações de cromonos arenitos do aqüífero (média 221 ppm) e em piroxênios (6000 ppm), um dos principais minerais pesados encontrados nos sedimentos. Além disso, não foram observadas outras possíveis fontes de contaminação difusas ou pontuais naárea de estudo. Uma estratificação da qualidade da água no aqüífero foi observada e as mais elevadas concentrações de Cr6+ foram detectadas na base do aqüífero (0,12 mg.L-1), onde as águas subterrâneas apresentam valores elevados de potencial redox (Eh = 472,5 mV) e de pH (8,61). A origem do Cr6+ na água deve estar associada com o intemperismo do piroxênio (augita), seguida da oxidação do Cr3+ pelos óxidos de manganês. As maiores concentrações de Cr6+ estão provavelmente ligadas com reações de desorção, devido ao pH anomalamentealcalino da água subterrânea na base do aqüífero.

Anomalous concentrations of hexavalent chromium have been detected in ground-water of the Adamantina Aquifer inat least 54 municipalities located in the northwestern region of the State of São Paulo, southeast Brazil, occasionallyexceeding the permitted limit for human consumption (0.05 mg.L-1). An investigation was conducted in the municipality of Urânia, where the highest concentrations of chromium were detected regionally. It was defined that the originof this contamination is natural, since high concentrations of chromium were detected in aquifer sandstones (averageof 221 ppm) and also in pyroxenes (6000 ppm), one of the main heavy minerals found in the sediments. Besides, noother possible diffuse or point sources of contamination were observed in the study area. Stratification of ground-waterquality was observed and the highest concentrations of Cr6+ were detected at the base of the aquifer (0.12 mg.L-1),where ground-water shows elevated values for redox potential (472.5 mV) and pH (8.61). The origin of Cr6+ in water may be associated with the weathering of pyroxene (augite), followed by the oxidation of Cr3+ by manganese oxides. The highest concentrations of Cr6+ are probably related to desorption reactions, due to the anomalous alkaline pHfound in ground-water at the base of the aquifer.

Few articles deal with lead and strontium isotopic analysis of water samples. The aim of this study was to define the chemical procedures for Pb and Sr isotopic analyses of groundwater samples from an urban sedimentary aquifer. Thirty lead and fourteen strontium isotopic analyses were performed to test different analytical procedures. Pb and Sr isotopic ratios as well as Sr concentration did not vary using different chemical procedures. However, the Pb concentrations were very dependent on the different procedures. Therefore, the choice of the best analytical procedure was based on the Pb results, which indicated a higher reproducibility from samples that had been filtered and acidified before the evaporation, had their residues totally dissolved, and were purified by ion chromatography using the Biorad® column. Our results showed no changes in Pb ratios with the storage time.

Indicadores, para recursos hídricos subterrâneos, têm sido utilizados principalmente para a avaliação da situação atual e tendência de degradação, com relação tanto à quantidade (sub- ou super-exploração) como à qualidade (contaminações natural e antrópica). Neste sentido, este trabalho apresenta a aplicação de indicadores com o objetivo de obter um quadro geral da situação dos recursos hídricos nas 22 Unidades de Gerenciamento de Recursos Hídricos (UGRHI) do Estado de São Paulo. Foram aplicados 7 indicadores (I1 a I7) com o objetivo de fornecer uma visão geral com relação à dependência (I1 e I2), disponibilidade (I3 e I4), e qualidade (I5, I6 e I7) da água subterrânea. No que se refere ao abastecimento público (indicador 1), 9 UGRHIs apresentam alta ( > 50% da população é suprida por água subterrânea), 6, intermediária (49 a 25%) e 7, baixa ( < 24%) dependência do recurso hídrico subterrâneo. Os indicadores 3 e 4 mostram que o recurso ainda apresenta grande potencial para explotações adicionais na maioria das UGRHIs, no entanto há evidências de superexploração nas bacias do Alto Tietê, Turvo/Grande e Pardo e baixa disponibilidade nas bacias do Alto Tietê, Piracicaba/Capivari/Jundiaí, e Turvo/Grande. O indicador 5 (vulnerabilidade natural dos aqüíferos) aponta que as UGRHIs 2, 4, 8, 13, 14 e 18 a 22 (parte da área aflorante do Sistema Aqüífero Guarani) precisam ser mais cuidadosamente consideradas, principalmente quando grandes cargas contaminantes potenciais estiverem presentes. O indicador 6 revela que a qualidade natural das águas subterrâneas é de modo geral excelente, ainda que 3 UGRHIs necessitem de cuidados especiais especiais devido à sua contaminação por cromo e flúor. O indicador 7 mostra uma forte relação entre a ocorrência da contaminação das águas subterrâneas e densidade/tipo de ocupação territorial.

Indicators, for groundwater resources, have mostly been employed to define the present status and the degradation tendency, regarding both quantity (under- or overexploitation) and quality (natural and anthropic contamination). This work presents the application of indicators in order to draw a picture of the groundwater resources situation in the 22 Water Resource Management Units (WRMU) of the State of São Paulo. The seven Indicators (I1 to I7) applied provide a general overview of groundwater dependence (I1, I2), availability (I3, I4), and quality (I5, I6, I7). Considering public supply (Indicator 1), one observes that 9 WRMUs show high (>50% of the population supplied by groundwater), 6, intermediate (49-25%), and 7, low (<24%) dependence on groundwater. Indicators 3 and 4 show that the resource still presents a great potential for further abstractions in most of the WRMUs, although there is evidence of overexploitation in the Upper Tietê, Turvo/Grande, and Pardo basins, and low availability in the Upper Tietê, Piracicaba/Capivari/Jundiai, and Turvo/Grande. Indicator 5 (aquifer natural vulnerability) denotes that the WRMUs 2, 4, 8, 13, 14 and 18-22 (part of the recharge area of Guarani Aquifer System) need more attention mainly where large contaminant loads are present. Indicator 6 shows the general excellent natural quality of groundwater, although it also denotes that 3 WRMUs need special consideration due to chromium and fluoride contamination. Indicator 7 demonstrates a close relationship between groundwater contamination occurrence and density/type of land occupation.