Hidrogeochemistry and water quality index from Alto Jacaré-Pepira Watershed (SP), Brazil

Estudos hidrogeoquímicos vem sendo utilizados com o objetivo de se definir as reações químicas resultantes da interação água-rocha que são responsáveis por fornecer as características naturais das águas superficiais, bem como indicar os efeitos da ação antrópica sobre a sua qualidade, e assim averiguar interferências na disponibilidade hídrica. Inserida na bacia hidrográfica do Rio Tietê-Jacaré, a sub-bacia do Alto Jacaré Pepira (SP) foi selecionada para este estudo devido a sua relativa complexidade geológica e inserção em uma importante área de recarga do Sistema Aquífero Guarani (SAG), na qual os recursos hídricos representam uma importante atração turística, especialmente para a cidade de Brotas (SP). Foram coletadas 17 amostras de águas superficiais, com o objetivo de determinar o Índice de Qualidade da Água (IQA), bem como avaliar sua composição química. Os valores de IQA variaram de 63 a 82, indicando que a qualidade da água pode ser considerada “Boa”. A condutividade elétrica apresenta boa correlação com as concentrações de sólidos totais em suspensão e sólidos totais dissolvidos. Quimicamente as águas da bacia são caracterizadas pela presença de HCO3 - como principal ânion, com concentrações variando de 4,12 mg L-1 a 44,50 mg L-1, e como principais cátions o Ca2+ e o Mg2+, com concentrações variando de 0,38 mg L-1 a 11,60 mg L-1 e de 0,55 mg L-1a 3,20 mg L-1, respectivamente, o que classifica as águas como bicarbonatadas-cálcicas ou magnesianas. A avaliação global das amostras possibilitou a constatação da pequena influência exercida pela ação antrópica sobre os corpos d’água, refletida nos valores de IQA e nas baixas concentrações de Cl- e NO3 - . A dissolução e intemperismo dos minerais presentes nas rochas e no solo da área de estudo são os processos geoquímicos responsáveis pela composição da água superficial na sub-bacia do Alto Jacaré-Pepira.Hydrogeochemical studies have been used in order to define chemical reactions produced by water-rock interactions that are responsible to imprint the natural characteristics of surface water, as well as indicate the effects of anthropic activities over water quality, providing information about water availability. Located in Tietê-Jacaré Basin, the Upper Jacaré-Pepira watershed was selected for this study due to its relative geological complexity, to be inserted in an important recharge area of the Guarani Aquifer System (GAS), in which water resources are an important tourist attraction, especially for the city of Brotas (SP). Seventeen river water samples have been collected, in order to determine the Water Quality Index (WQI) as well as evaluate their chemical composition. WQI values vary from 63 to 82, and the water quality classified as “Good”. Electrical conductivity presents strong correlation with total suspended solids and total dissolved solids. The main anion present in water composition is HCO3 - showing concentrations varying from 4.12 mg L-1 to 44.50 mg L-1, and Ca2+ and Mg2+ as the main cations, presenting concentrations ranging from 0.38 mg L-1 to 11.60 mg L-1 and 0.55 mg L-1 to 3.20 mg L-1, respectively. Based on chemical composition, river waters were classified as calcium or magnesium bicarbonate type. The overall assessment of the samples indicated the little influence of anthropic activities over water bodies, revealed by WQI values and low concentrations of Cl- e NO3 - . Dissolution and weathering of minerals forming rocks and soil from study area are the main geochemical process responsible by final water chemical composition in the Upper Jacaré-Pepira watershed

Potencial hidromineral dos aquíferos do estado de São Paulo

O estado de São Paulo lidera a produção brasileira de água mineral. Devido ao seu complexo arcabouço hidrogeológico, composto por vários aquíferos sedimentares e fraturados, as águas minerais apresentam diferentes características hidrominerais. Assim, o principal objetivo foi avaliar o potencial hidromineral dos aquíferos paulistas, fundamentado pelo Código de Águas Minerais (CAM) e legislações internacionais correlatas, a partir de uma base de dados pública de laudos analíticos de 276 poços de águas subterrâneas da Companhia Ambiental do Estado de São Paulo (CETESB). Baseado nas concentrações de Sólidos Totais Dissolvidos (STD), observou-se que as águas subterrâneas possuem grau variável de mineralização, sendo as águas mais mineralizadas associadas aos sistemas aquíferos Serra Geral (SASG), Tubarão (SAT) e Bauru (SAB). Entretanto, apenas 8,7% das águas se enquadrariam como mínimo e baixo teores de STD pela legislação dos Estados Unidos. Similarmente, apenas duas amostras seriam enquadradas como muito pouco mineralizadas e 81,5% em pouco mineralizadas pela legislação europeia. Pelas classificações dispostas pelo CAM, as amostras foram caracterizadas pela temperatura, predominantemente, como frias e hipotermais, e uma pequena parcela como mesotermais e hipotermais. As águas mais frias prevaleceram no aquífero Cristalino (SAC), enquanto as águas de maiores temperaturas ocorreram no Guarani (SAG). Todo os aquíferos possuíram potencial hidromineral pela classificação química, pela concentração de flúor, seguido em ordem decrescente, pelo lítio no SAC, o vanádio no SASG, a alcalina bicarbonato no SAT, sulfato e selênio de forma mista no SAT e SASG

ISOTOPIC COMPOSITION OF GROUNDWATER AND PRECIPITATION IN NEBRASKA, USA

Groundwater is vital worldwide for water supply, agriculture and industry. Nearly 60% of all water use in Nebraska is from groundwater. Over 90% of groundwater is used for irrigation in Nebraska, which has the largest area of irrigated land in the United States. Many Nebraskans depend on groundwater for drinking water, both from private wells and municipal wells. The sustainability of groundwater resources is dependent on groundwater recharge. The recharge processes, as well as climatic patterns, influence the stable isotope signatures. Based on weekly samples collected at two monitoring stations managed by the National Atmospheric Deposition Program (NADP), Harvey (2001) and Harvey and Welker (2000) presented an overview of isotopic composition of precipitation in Nebraska. Two stations, located in Mead and North Platte (Figure 1), were monitored from 1992-1994 and 1989-1994, respectively. This data illustrated patterns in the isotopic composition of precipitation, both spatially and seasonally. To better understand the recharge processes, over 789 groundwater samples were collected across Nebraska in 2011 and their isotopic signatures analyzed. While other studies have evaluated isotope ratios (seasonal ratios) (Jasechko et al., 2017; Sanchéz-Murillo and Birkel., 2016), in this study we compared the precipitation signals. The objective of this study was to investigate recharge characteristics based on stable isotope signatures of groundwater and comparisons of the isotopic composition of groundwater and precipitation across Nebraska

Recharge Seasonality Based on Stable Isotopes: Nongrowing Season Bias Altered by Irrigation in Nebraska

The sustainability of groundwater resources for agricultural and domestic use is dependent on both the groundwater recharge rate and groundwater quality. The main purpose of this study was to improve understanding of the timing, or seasonality, of groundwater recharge through the use of stable isotopes. Based on 659 groundwater samples collected from aquifers underlying Natural Resources Districts in Nebraska, the isotopic composition of groundwater (δ 2H, δ 18O) was compared to that of precipitation by (a) mapping the isotopic composition of groundwater samples and (b) mapping a seasonality index for groundwater. Results suggest that for the majority of the state, groundwater recharge has a nongrowing season signature (October – April). However, the isotopic composition of groundwater suggests that in some intensively irrigated areas, human intervention in the water cycle has shifted the recharge signature toward the growing season. In other areas, a different human intervention (diversion of Platte River water for irrigation) has likely produced an apparent but possibly misleading nongrowing season recharge signal because the Platte River water differs isotopically from local precipitation. These results highlight the need for local information even when interpreting isotopic data over larger regions. Understanding the seasonality of recharge can provide insight into the optimal times to apply fertilizer, specifically in highly conductive soils with high leaching potential. In areas with high groundwater nitrate concentrations this information is valuable for protecting the groundwater from further degradation. While previous studies have framed nongrowing season recharge within the context of future climate change, this study also illustrates the importance of understanding how historical human intervention in the water cycle has affected groundwater recharge seasonality and subsequent implications for groundwater recharge and quality

Baseflow and water resilience variability in two water management units in southeastern Brazil

Changes in climate and water demand in densely populated regions increasingly affect hydrological systems, and, in turn, impact socioeconomic conditions. In this case study, we identify how the hydrogeological frameworks of two water resource management units, Tietê-Jacaré (TJ) and Piracicaba-Capivari-Jundiaí (PCJ) in Sao Paulo state (Brazil), control the baseflow processes and resilience in the face of streamflow fluctuations in response to anthropogenic activities and climate variation. The results reveal between 40% and 75% contributions of baseflow to total streamflow in basins overlying crystalline and sedimentary aquifers. The basins in PCJ which mostly overly crystalline aquifers, have shorter water residence times and greater dependence on surface water. Therefore, streamflow in the PCJ basins is vulnerable during the drought period and the management model affected the water resilience of the basins (transfer of water to Cantareira System). The TJ basins have greater streamflow contributions from aquifer discharge linked to the presence of important sedimentary aquifers, which improves resilience under changing rainfall patterns, these basins present a more stable situation of resilience. Ultimately, the two management units require different planning strategies with adaptive and dynamic actions to mitigate the social, economic, and environmental effects caused by the variability and reduction of water sources

Data Descriptor: Daily observations of stable isotope ratios of rainfall in the tropics

We present precipitation isotope data (δ2H and δ18O values) from 19 stations across the tropics collected from 2012 to 2017 under the Coordinated Research Project F31004 sponsored by the International Atomic Energy Agency. Rainfall samples were collected daily and analysed for stable isotopic ratios of oxygen and hydrogen by participating laboratories following a common analytical framework. We also calculated daily mean stratiform rainfall area fractions around each station over an area of 5° x 5° longitude/latitude based on TRMM/GPM satellite data. Isotope time series, along with information on rainfall amount and stratiform/convective proportions provide a valuable tool for rainfall characterisation and to improve the ability of isotope-enabled Global Circulation Models to predict variability and availability of inputs to fresh water resources across the tropics.Fil: Munksgaard, Niels C.. James Cook University; Australia. Charles Darwin University. School of Environmental Research; AustraliaFil: Kurita, Naoyuki. Nagoya University; JapónFil: Sánchez Murillo, Ricardo. Universidad Nacional; Costa RicaFil: Ahmed, Nasir. Bangladesh Atomic Energy Commission; BangladeshFil: Araguas, Luis. International Atomic Energy Agency (iaea); AustriaFil: Balachew, Dagnachew L.. International Atomic Energy Agency (iaea); AustriaFil: Bird, Michael I.. James Cook University; AustraliaFil: Chakraborty, Supriyo. Indian Institute of Tropical Meteorology; IndiaFil: Kien Chinh, Nguyen. Center for Nuclear Techniques; VietnamFil: Cobb, Kim M.. Georgia Institute of Technology; Estados UnidosFil: Ellis, Shelby A.. Georgia Institute of Technology; Estados UnidosFil: Esquivel Hernández, Germain. Universidad Nacional; Costa RicaFil: Ganyaglo, Samuel Y.. National Nuclear Research Institute; GhanaFil: Gao, Jing. Chinese Academy of Sciences; República de ChinaFil: Gastmans, Didier. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Kaseke, Kudzai F.. Indiana University-Purdue University Indianapolis; India. University of California Santa Barbara; Estados UnidosFil: Kebede, Seifu. Addis Ababa University; EtiopíaFil: Morales, Marcelo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Mueller, Moritz. Swinburne University of Technology; MalasiaFil: Poh, Seng Chee. Universiti Malaysia Terengganu; MalasiaFil: Santos, Vinícius dos. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Shaoneng, He. Nanyang Technological University; SingapurFil: Wang, Lixin. Indiana University-Purdue University Indianapolis; IndiaFil: Yacobaccio, Hugo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Zwart, Costijn. James Cook University; Australi

Hidrogeologia e hidroquímica do Sistema Aqüífero Guarani na porção ocidental da bacia sedimentar do Paraná

O fluxo das águas subterrâneas no SAG, em sua porção ocidental, é caracterizado pela existência de três áreas de recarga regional, localizadas em Mato Grosso do Sul e Goiás. A partir destas áreas de recarga o fluxo regional é radial direcionado para o centro da Bacia do Paraná. Em algumas porções das zonas de aforamento ocorrem fluxos localizados de descarga. As águas apresentam características químicas que permitem sua classificação em: bicarbonatadas cálcicas ou calco-magnesianas, bicarbonatadas sódicas e bicarbonatadas cloretadas/sulfatadas sódicas, representando, nesta ordem, a sua evolução hidroquímica. Os mecanismos envolvidos nesta evolução são: dissolução de feldspatos e remoção do cimento carbonático do arcabouço mineral dos arenitos, seguido por troca iônica, responsável pelo aumento nas concentrações de sódio e diminuição nas concentrações de cálcio e, finalmente, o enriquecimento em cloreto e sulfato, oriundos dos aqüíferos sotopostos ao SAG. Foram reconhecidas três unidades hidroestratigráficas distintas no SAG: superior, representada pelos arenitos eólicos limpos, da Formação Botucatu, intenuediária, representada por arenitos finos e argilosos, e inferior, por arenitos finos, pouco argilosos, estas duas últimas unidades pertencentes à Formação Pirambóia.The groundwater flow pattern in the occidental portion of SAG (Guarani Aquifer System) is characterized by the existence of three regional recharge areas located in Mato Grosso do Sul and Goiás states. From these areas ofrecharge the regional flow is radial and directed toward the center of Paraná Sedimentary Basin. Local discharge flows occurs in portions of outcrop regions. The groundwater can be classified as calcium or calcium-magnesium bicarbonate type, sodium bicarbonate type and sodium bicarbonate/chloride/sulphate type, representing in this sequence its hydrochemical evolution. The mechanisms responsible for this evolution are dissolution of feldspars and remova! of the carbonate cement of the sandstones mineral framework, followed by ionic exchange, responsible for the increase in the sodium concentration and decrease of calcium, and, finally, the enrichment in chloride and sulphate derived from underlying aquifers units. Three distinct hydrostratigraphics units in the SAG have been recognized: the upper unit is represented by aeolian sandstones from Botucatu Formation, the intermediate, represented by the fine and argillaceous sandstones, and the lower unit is constituted by fine sandstones with low content in clays, these last two units belong to the Pirambóia formation.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

ISOTOPIC COMPOSITION OF GROUNDWATER AND PRECIPITATION IN NEBRASKA, USA

Groundwater is vital worldwide for water supply, agriculture and industry. Nearly 60% of all water use in Nebraska is from groundwater. Over 90% of groundwater is used for irrigation in Nebraska, which has the largest area of irrigated land in the United States. Many Nebraskans depend on groundwater for drinking water, both from private wells and municipal wells. The sustainability of groundwater resources is dependent on groundwater recharge. The recharge processes, as well as climatic patterns, influence the stable isotope signatures. Based on weekly samples collected at two monitoring stations managed by the National Atmospheric Deposition Program (NADP), Harvey (2001) and Harvey and Welker (2000) presented an overview of isotopic composition of precipitation in Nebraska. Two stations, located in Mead and North Platte (Figure 1), were monitored from 1992-1994 and 1989-1994, respectively. This data illustrated patterns in the isotopic composition of precipitation, both spatially and seasonally. To better understand the recharge processes, over 789 groundwater samples were collected across Nebraska in 2011 and their isotopic signatures analyzed. While other studies have evaluated isotope ratios (seasonal ratios) (Jasechko et al., 2017; Sanchéz-Murillo and Birkel., 2016), in this study we compared the precipitation signals. The objective of this study was to investigate recharge characteristics based on stable isotope signatures of groundwater and comparisons of the isotopic composition of groundwater and precipitation across Nebraska