Roger Dias Gonçalves

Pertamina (Indonesia)

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Chang Hung Kiang

Universidade Estadual Paulista (Unesp)

Elias Hideo Teramoto

Universidade Estadual Paulista (Unesp)

Bruno Zanon Engelbrecht

Universidade Estadual Paulista (Unesp)

Márcia Regina Stradioto

Universidade Estadual Paulista (Unesp)

Reiner Stollberg

Helmholtz Centre for Environmental Research

H. Weiß

Helmholtz Centre for Environmental Research

Miguel Angel Alfaro Soto

Universidade Estadual Paulista (Unesp)

Hyungjoon Chang

Chungbuk National University

Hung Kiagn Chang

Universidade Estadual Paulista (Unesp)

Martinus Th. van Genuchten

Universidade Federal do Rio de Janeiro

Cooperative Institutions

Universidade Estadual Paulista (Unesp)

Instituto de Geociencias

International Atomic Energy Agency

University of California, Riverside

Helmholtz Centre for Environmental Research

Peruvian University of Applied Sciences

University of the Andes

Universidad de Los Andes

California State University Los Angeles

Chungbuk National University

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Hydrochemistry of the Guarani Aquifer System modulated by mixing with underlying and overlying hydrostratigraphic units

Journal of Hydrology Regional Studies (2020)

Elias Hideo Teramoto Roger Dias Gonçalves Chang Hung Kiang

São Paulo State, Southeastern, Brazil. Several studies were conducted on the Guarani Aquifer System (GAS), with as main focus the identification of major stratigraphic units and hydrodynamic properties governing groundwater flow. Geochemical assessment studies of the GAS focused on hydrochemical and isotopic characterization. Current understanding is that progressive rock–water interactions control the observed hydrochemical zonation. Based on available analyses of the overlying Serra Geral Aquifer System (SGAS) and the deeper Permian Aquifer System (PAS), along with numerical simulation of mixing processes, we concluded that the hydrochemistry of the GAS is modulated by its mixing with groundwater inputs from overlying and underlying aquifers. Importantly, our work indicates that >50 % of the Guarani Aquifer System groundwater recharge in São Paulo State comes from Serra Geral Aquifer System seepage. This finding has critical implications regarding groundwater management, mass-balance calculations and estimations of groundwater residence times.

Aquifer test

Groundwater model

10.1016/j.ejrh.2020.100713

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Citations (18)

Application of GRACE Data for Quantifying Mesoscale Groundwater Stress - Urucuia Aquifer System, Northeastern Brazil

2015 AGU Fall Meeting (2015)

Reiner Stollberg Roger Dias Gonçalves H. Weiß Hyungjoon Chang

Source

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Using GRACE to quantify the depletion of terrestrial water storage in Northeastern Brazil: The Urucuia Aquifer System

The Science of The Total Environment (2019)

Roger Dias Gonçalves Reiner Stollberg H. Weiß Chang Hung Kiang

Water storage

Water balance

10.1016/j.scitotenv.2019.135845

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Citations (45)

Regional Groundwater Modeling of the Guarani Aquifer System

Water (2020)

Roger Dias Gonçalves Elias Hideo Teramoto Chang Hung Kiang

The Guarani Aquifer System (GAS) is a strategic transboundary aquifer system shared by Brazil, Argentina, Paraguay and Uruguay. This article presents a groundwater flow model to assess the GAS system in terms of regional flow patterns, water balance and overall recharge. Despite the continental dimension of GAS, groundwater recharge is restricted to narrow outcrop zones. An important part is discharged into local watersheds, whereas a minor amount reaches the confined part. A three-dimensional finite element groundwater-flow model of the entire GAS system was constructed to obtain a better understanding of the prevailing flow dynamics and more reliable estimates of groundwater recharge. Our results show that recharge rates effectively contributing to the regional GAS water balance are only approximately 0.6 km3/year (about 4.9 mm/year). These rates are much smaller than previous estimates, including of deep recharge approximations commonly used for water resources management. Higher recharge rates were also not compatible with known 81Kr groundwater age estimates, as well as with calculated residence times using a particle tracking algorithm.

Depression-focused recharge

Groundwater model

10.3390/w12092323

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Citations (19)

Caracterização hidroquímica e isotópica dos aquíferos fissurais da região de Itabuna/BA

Águas Subterrâneas (2018)

Elias Hideo Teramoto Bruno Zanon Engelbrecht Roger Dias Gonçalves Chang Hung Kiang

Os aquíferos cristalinos representam importantes reservas de águas em termos mundiais e são caracterizados pela complexidade que governam o movimento e o armazenamento da água em suas descontinuidades geológicas. Igualmente complexos são os mecanismos atuantes na interação rocha/água. O entendimento dos processos físicos e geoquímicos atuantes nestes aquíferos é crucial para sua gestão. Este trabalho apresenta uma caracterização hidroquímica preliminar das águas do aquífero fissural na região de Itabuna/BA, a partir da identificação dos tipos hidroquímicos dominantes. As análises químicas indicam elevada variabilidade da composição química da água, que pode estar associado à ocorrência de vários processos distintos, incluindo a interação com a água marinha e diferentes graus de interação com as rochas que hospedam a água em suas descontinuidades geológicas. As amostras de águas subterrâneas foram reunidas em dois grupos distintos: o primeiro grupo é representado por água do tipo cloretado sódico e menores valores de condutividade elétrica, associados às amostras coletadas nas porções mais rasas de sub-superfície; o segundo grupo é representado por tipos hidroquímicos bicarbonato sódico, cálcico ou cálcio-magnesianos, provavelmente associadas às águas com elevado grau de interação com as rochas do aquífero, proveniente de recarga pretérita. Os resultados de análise isotópica da água subterrânea e meteórica sugerem a existência de um leve excesso de deutério, decorrente de condições climatológicas locais.

10.14295/ras.v32i2.29151

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Citations (3)

Groundwater isotope ratios reflect convective and stratiform (paleo)precipitation fractions in Brazil

Journal of Hydrology (2020)

Chang Hung Kiang Roger Dias Gonçalves Pradeep Aggarwal Márcia Regina Stradioto Emilio C.B. Hespanhol

Speleothem

δ18O

Paleoclimatology

10.1016/j.jhydrol.2020.124801

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Citations (20)

Probabilistic backward location for the identification of multi-source nitrate contamination

Stochastic Environmental Research and Risk Assessment (2021)

Elias Hideo Teramoto Bruno Zanon Engelbrecht Roger Dias Gonçalves Chang Hung Kiang

10.1007/s00477-020-01966-y

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Citations (4)

Quasi‐Saturated Layer: Implications for Estimating Recharge and Groundwater Modeling

Ground Water (2019)

Roger Dias Gonçalves Elias Hideo Teramoto Bruno Zanon Engelbrecht Miguel Angel Alfaro Soto Chang Hung Kiang

Abstract This study presents an extension of the concept of “quasi‐saturation” to a quasi‐saturated layer, defined as the uppermost dynamic portion of the saturated zone subject to water table fluctuations. Entrapped air here may cause substantial reductions in the hydraulic conductivity ( K ) and fillable pore water. Air entrapment is caused by a rising water table, usually as a result of groundwater recharge. The most significant effects of entrapped air are recharge overestimation based on methods that use specific yield ( S y ), such as the water table fluctuation method (WTF), and reductions in K values. These effects impact estimation of fluid flow velocities and contaminant migration rates in groundwater. In order to quantify actual groundwater recharge rates and the effects of entrapped air, numerical simulations with the FEFLOW (Version 7.0) groundwater flow model were carried out using a quasi‐saturated layer for a pilot area in Rio Claro, Brazil. The calculated recharge rate represented 16% of the average precipitation over an 8‐year period, approximately half of estimates using the WTF method. Air entrapment amounted to a fillable porosity of 0.07, significant lower that the value of 0.17 obtained experimentally for S y . Numerical results showed that the entrapped air volume in the quasi‐saturated layer can be very significant (0.58 of the air fraction) and hence can significantly affect estimates of groundwater recharge and groundwater flow rates near the water table.

Saturation (graph theory)

10.1111/gwat.12916

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Citations (27)

Modeling Rock-Water Interaction of Fractured Aquifer in Itabuna/BA Region

Anuário do Instituto de Geociências (2019)

Elias Hideo Teramoto Roger Dias Gonçalves Márcia Regina Stradioto Bruno Zanon Engelbrecht Hung Kiagn Chang

Este trabalho objetivou investigar os mecanismos geoquímicos que governam as fortes variações hidroquímicas nos aquíferos fissurais da região de Itabuna/BA. Enquanto a mineralogia original metatonalítica/metatrondhjemitíca é composta principalmente por plagioclásio e quartzo, as rochas metabásicas são representadas por plagioclásios, piroxênios e anfibólios. Os principais minerais gerados pela interação rocha/água são a zeólitas, cloritas e montmorilonitas. Conceitualmente, dois processos distintos atuam nas varrições hidroquímicas do aquífero. O primeiro é representado pela interação da água meteórica com os aerossóis marinhos, enquanto o segundo é representado pela atuação da evapotranspiração que incrementa a salinidade da água e o terceiro é representado pela interação com as rochas metatonalíticas/ metatrondhjemíticas e metabásicas. As simulações geoquímicas foram capazes de reproduzir as variações composicionais observadas em campo. Enquanto o incremento de Cl- pode ser atribuído à interação da água meteórica precipitada com aerossóis marinhos e posterior evaporação, o incremento de Ca2+, Na+, Mg2+ e HCO3 - é atribuído ao intemperismo de plagioclásios, piroxênios e anfibólios.

10.11137/2019_1_735_741

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Citations (7)