Abstract
Geostatistical modeling, using airborne and borehole electromagnetic data, was used to estimate electrical conductivity in groundwater within fractured paragneisses and migmatites in a semi-arid climate in northeastern Brazil. Despite the geologic heterogeneity of crystalline aquifers, the use of high resolution helicopter electromagnetic (HEM) data enabled the characterization of groundwater electrical conductivity where data from drilled wells were insufficient. The tacit assumption is that HEM measurements can be used to relate rock electrical conductivity to groundwater electrical conductivity. In this study, the HEM data were used as an external drift variable in non-stationary estimation and stochastic simulation to identify the variability of groundwater electrical conductivity. Validation tests, comparing predicted values for groundwater conductivity with measurements in new wells, confirmed the success of these models in locating fresh groundwater sources in crystalline bedrock.
Résumé
A fin d'estimer la conductivité électrique des eaux souterraines dans des paragneiss et migmatites sous climat semi-aride au Nord-Est du Brésil, une modélisation géostatistique a été mise en œuvre à partir de données électromagnétiques de forage et aériennes. Malgré l'hétérogénéité géologique des aquifères cristallin, l'utilisation de données héliportées électromagnétiques (HEM) a permis de caractériser la conductivité électrique là où les données de forages étaient insuffisantes. L'hypothèse tacite est que les mesures HEM peuvent être utilisées pour relier la conductivité électrique des roches à celle des eaux souterraines. Les tests de validation ont comparé les valeurs estimées de conductivité électrique dans les eaux souterraines aux mesures dans des puits récents : ils confirment la pertinence de ces modèles pour localiser les ressources en eau potable dans le socle cristallin.
Kurzfassung
Die elektrische Leitfähigkeit des Grundwassers in zerklüfteten Paragneissen und Migmatiten einer semi-ariden Region im Nordosten Brasiliens wurde unter Nutzung der geostatistischen Modellierung abgeschätzt, basierend auf aus der Luft oder in Bohrlöchern gesammelter elektromagnetischer Daten. Trotz der geologischen Heterogenität der Grundwasserhorizonte in kristallinem Gestein erlaubte die Nutzung von hochauflösenden, Helikopter basierenden Daten (helicopter electromagnetic, HEM) die Charakterisierung der elektrischen Leitfähigkeit des Grundwassers auch dort, wo sich Bohrlochdaten als unzureichend erwiesen. Dies geschah unter der stillschweigenden Annahme, dass sich HEM-Messungen dazu verwenden lassen, die elektrische Leitfähigkeit des Gesteins und des Grundwassers miteinander in Beziehung zu setzen. In dieser Arbeit wurden die HEM-Daten als externe Drift-Variable einer nicht-stationären Abschätzung und stochastischen Simulation verwendet, um die Variabilität der elektrischen Leitfähigkeit des Grundwassers zu bestimmen. Verifizierende Tests, die die auf diese Weise vorhergesagte Werte der Grundwasserleitfähigkeit mit Messungen aus neuen Bohrlöchern verglichen, bestätigten, dass sich unter Verwendung dieser Methodik Süsswasserquellen in kristallinem Grundgestein lokalisieren lassen.
Resumen
Se usó un modelo geoestadístico, utilizando datos electromagnéticos provenientes de perforaciones y equipos aerotransportados para estimar la conductividad eléctrica en el agua subterránea dentro de paragneises y migmatitas fracturados, en un clima semi árido en el noreste de Brasil. A pesar de la heterogeneidad geológica de los acuíferos cristalinos, el uso de datos electromagnéticos de alta resolución desde helicóptero (HEM) permitió la caracterización de la conductividad eléctrica del agua subterránea donde los datos de pozos perforados eran insuficientes. La suposición tácita es que las medidas HEM pueden ser usados para relacionar la conductividad eléctrica de la roca y la conductividad eléctrica del agua subterránea. En este estudio, los datos HEM fueron usados como una variable externa guía en una estimación no estacionaria y simulación estocástica para identificar la variabilidad de la conductividad eléctrica del agua subterránea. Las pruebas de validación, comparando valores predichos de conductividad del agua subterránea con medidas en pozos nuevos, confirmaron el acierto de estos modelos para localizar fuentes de aguas subterráneas dulces en rocas cristalinas.
摘要
基于空中和钻孔电磁数据, 用地质统计方法计算了巴西东北部半干旱的副片麻岩与混合岩地区裂隙地下水的电导率. 尽管结晶岩含水层存在地质非均一性, 高分辨率直升机航空电磁数据 (HEM) 的可以用于钻井数据较少地区的地下水电导率确定. 很显然, 我们的假设是HEM测量可以把岩石的电导率与地下水的电导率联系起来. 本研究将HEM数据作为外部漂移变量进行非平稳计算和随机模拟, 以查明地下水电导率的变化特征. 将地下水电导率的预测值与新井中的测量值进行比较, 检验结果表明这些模型能够应用于在结晶基岩中确定淡水水源的位置.
Resumo
Foi utilizada modelação geoestatística, com base em dados electromagnéticos aéreos e em furos, para estimar a conductividade eléctrica das águas subterrâneas em paragnaisses e migmatitos fracturados, num clima semi-árido do nordeste do Brasil. Apesar da heterogeneidade geológica dos aquíferos cristalinos, o uso de dados electromagnéticos de alta resolução, obtidos a partir de helicóptero (HEM), permitiu a caracterização da conductividade eléctrica das águas subterrâneas, onde os dados obtidos a partir de poços perfurados eram insuficientes. O pressuposto tácito é que as medições HEM podem ser usadas para relacionar a conductividade eléctrica das rochas com a conductividade eléctrica das águas subterrâneas. Neste estudo, os dados HEM foram usados como uma variável externa da deriva, em estimativa não-estacionária e em simulação estocástica, para identificar a variabilidade da conductividade eléctrica nas águas subterrâneas. Testes de validação, comparando os valores previstos para a conductividade nas águas subterrâneas com as medições em novos furos, confirmaram o sucesso destes modelos na localização de origens de água doce subterrânea em rochas cristalinas.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Becker A, Barringer AR, Annan AP (1987) Airborne electromagnetics 1978–1988. In: Fitterman DV (ed) Developments and applications of modern airborne electromagnetic surveys. US Geol Surv Bull 1925:9–20
Bleines C, Perseval S, Rambert F, Renard D, Touffait Y (2000) ISATIS software manual. Geovariances & Ecole des Mines de Paris
Brodie R, Green A, Munday T (2004) Constrained inversion of RESOLVE airborne electromagnetic data: Riverland, South Australia. CRCLEME Open file report 175. CRCLEME, Bentley, Australia, 49 pp
Chambers RL, Yarus JM, Hird KB (2000) Petroleum geostatistics for nongeostaticians, part 2. The Leading Edge 19(6):592–599
Clark I (1979) Practical geostatistics. Applied Science, London
Coppa I, Woodgate P, Webb A (1998) Improving the management of dryland salinity in Australia through the national airborne geophysics project. In: Brian S, Fitterman D, Holladay S, Guimin L (eds) AEM98, The international Conference on Airborne Electromagnetics. Explor Geophys 29(1–2):230–233
Debeglia N, Martelet G, Perrin J, Truffert C, Ledru P, Tourlière B (2005) Semi-automated structural analysis of high resolution magnetic and gamma-ray spectrometry airborne surveys. J Appl Geophys 58:13–28
Deutsch CV (1993) Kriging in a finite domain. Math Geol 25(1):41–52
Fraser DC (1978) Resistivity mapping with an airborne multicoil electromagnetic system. Geophysics 43:144–172
Gómez-Hernández JJ (2005) Geostatistics. In: Rubin Y, Hubbard SS (eds) Hydrogephysics. Springler, Amsterdam, pp 59–83
Instituto de Planejamento do Estado do Ceará (IPLANCE) (1995) Atlas do Ceará (Ceará Atlas). IPLANCE, Fortaleza, Brazil, 64 pp
Lasa Engenharia e Prospecções S/A (2001) Projeto aerogeofísico água subterrânea no nordeste do Brasil, Blocos Juá (CE), Samambaia (PE) e Serrinha (RN). Relatório final do levantamento e processamento dos dados magnetométricos e eletromagnetométricos e seleção das anomalias eletromagnéticas [Northeastern Brazil groundwater aerogeophysical project: final report of the survey and processing of magnetometric and electromagnetometric data and selection of the electromagnetic anomalies]. Cooperação Canadá-Brasil, 3 vols, 3 CD-Roms, Lasa, Rio De Janeiro, Brazil. Available at http://proasne.net/Relatorio.pdf. Cited 12 October 2001
Mandrucci V, Taioli F, Araújo CC (2008) Groundwater favorability map using GIS multicriteria data analysis on crystalline terrain, São Paulo State. Brazil J Hydrol 357:153–173
Manoel Filho J (1996) Modelo de dimensão fractal para avaliação de parâmetros hidráulicos em meio fissural [Fractal dimension model for evaluation of hydraulic parameters in fissural domain]. PhD Thesis, Universidade de São Paulo, Brazil
McCafferty AE, McDougal RM (2008) Connecting airborne geophysical data to geologic structures. In: Verplanck PL (ed) Understanding contaminants associated with mineral deposits. US Geol Surv Circ 1328, Chap. L, pp 70–75
Meng Q, Hu H, Yu Q (2006) The application of an airborne electromagnetic system in groundwater resource and salinization studies in Jilin, China. J Environ Eng Geophys 11(2):103–109
Ministério da Saúde (2005) Portaria MS no. 518/2004/Ministério da Saúde, Secretaria de Vigilância em Saúde, Coordenação Geral de Vigilância em Saúde Ambiental, Série E. Legislação em Saúde [Legislation on health], Brasília. Ministério da Saúde, Rio de Janeiro
Oliveira MLde (1997) Análise das incertezas envolvidas na modelagem de reservatórios no contexto geoestatístico [Geostatistical approach of uncertainties analysis related to reservoir modeling]. Dissertação de Mestrado, UNICAMP, Campinas, São Paulo, Brazil
Palacky GJ (1986) Airborne resistivity mapping. Paper 86–22, Geological Survey of Canada, Ottawa, ON, 195 pp
Palacky GJ (1991) Resisitivity characteristics of geologic targets. In: Nabighian MN (ed) Electromagnetic methods in applied geophysics: theory, vol 1, no. 3. Investigations in geophysics series, SEG, Tulsa, OK, USA, pp 53–129
Pedersen LB, Persson L, Bastani M, Byström S (2009) Airborne VLF measurements and mapping of ground conductivity in Sweden. J Appl Geophys 67(3):193–268
Pine JG, Minty BRS (2005) Airborne hydrogeophysics. In: Rubin Y, Hubbard SS (eds) hydrogeophysics. Springer, Amsterdam, pp 333–357
PROASNE (2007) Northeast Brazil Groundwater Project. Web page of the cooperation between the Geological Surveys of Brazil and Canada, PROASNE. Available via http://proasne.net. Cited 12 October 2001
Rhén I, Thunehed H, Triumf C-A, Follin S, Hartley L, Hermansson J, Wahlgren C-H (2007) Development of a hydrogeological model description of intrusive rock at different investigation scales: an example from south-eastern Sweden. Hydrogeol J 15(1):47–69
Rubin Y, Hubbard SS (2005) Stochastic forward and inverse modeling: the “hydrogeophysical challenge”. In: Rubin Y, Hubbard SS (eds) Hydrogeophysics. Springer, Amsterdam, pp 487–511
Santos AC (2000) Noções de hidroquímica [Notions on hydrochemistry]. In: Feitosa FAC, Manoel Filho J (eds) Hidrogeologia: conceitos e aplicações, 2nd edn. CPRM/REFO, LABHID-UFPE, Fortaleza, Brazil
Sattel D, Kgotlhand L (2003) Modelling aquifer structures with airborne EM in the Boteti area, Botswana. Proceedings of Symposium on the Application of Geophysics to Engineering and Environmental Problems, April 2003, San Antonio, TX, USA
Silva OAda (2005) Análise de dados aerogeofísicos aplicada à exploração e ao gerenciamento de recursos hídricos subterrâneos [Analysis of airborne geophysical data applied to the exploration and management of groundwater resources]. PhD Thesis, Institute of Geosciences, Universidade Federal da Bahia, Brazil, 88 pp. Available at http://www.pggeofisica.ufba.br/resumos/pdf/d042a.pdf. Cited 12 May 2008
Silva CMSV, Vasconcelos MB, Santiago MMF (2001) Recarga e datação de poços no cristalino [Recharge and dating of drilled wells in the crystalline domain]. In: IV Simpósio de Hidrogeologia do Nordeste, 2001, Recife. Anais do IV Simpósio de Hidrogeologia do Nordeste, ABAS, São Paulo, Brazil, pp 8–14
Sousa MF, Albuquerque GA, Carvalho RR (1984) Cristalino na Paraíba: resultado obtido pela CDRM-PB no âmbito do Programa de Aproveitamento de Recursos Hídricos no Nordeste – PROHIDRO/SUDENE [Crystalline in Paraíba: results of CDRM-PB during the Northeastern Program for the Use of Hydric Resources – PROHIDRO/SUDENE]. In: Congresso Brasileiro de Águas Subterrâneas. III, 1984. Fortaleza, Anais 1, pp 128–146
Souza Filho OAde (1998) Geologia e mapa de previsão de ocorrência de água subterrânea. Folha SA.24-Y-D-V Irauçuba, Ceará [Geology and predictive map of groundwater occurrence, SA.24-Y-D-V Irauçuba sheet]. Dissertação de Mestrado. Universidade Federal de Ouro Preto, Brasil, 99 pp
Souza Filho OAde, Ribeiro JÁ, Veríssimo LS, Oliveira RGde, Gomes FEM, Brandão RdeL, Frizzo SJ, Oliveira JFde (2003) Projeto otimização de metodologias para prospecção de águas subterrâneas em rochas cristalinas. Relatório integrado de atividades 1999–2002: Bases para avaliação do projeto [Project for optimization of groundwater prospection methodologies in crystalline rocks: integrated report 1999–2002]. CPRM/REFO. Fortaleza, Brazil, 160 pp
Souza Filho OAde, Veríssimo LS, Silva CMS, Santiago MMF, Santiago MF (2004) Medidas hidroquímicas nas águas subterrâneas da região de Irauçuba, Norte do Ceará [Hydrochemical measures in Irauçuba groundwaters, north of Ceará]. In: Congresso Brasileiro de Águas Subterrâneas XIII, 2004. Cuiabá, CD-Rom. Available at http://www.cprm.gov.br/publique/media/medidas_hidroq.pdf. Cited 1 May 2007
Souza Filho OAde, Oliveira RG, Ribeiro JA, Veríssimo LS, Sá JU (2006) Interpretação e modelagens de dados de eletrorresistividade para locações de poços tubulares no aqüífero fissural da área-piloto Juá, Irauçuba-Ceará [Interpretation and modeling of electrical resistivity data for water well location in the fissural aquifer of Juá study-area]. Rev Geol DEGEO/UFC 19(1):7–21. Available at www.revistadegeologia.ufc.br/01_2006.pdf. Cited 3 April 2007
Souza Filho OAde, Silva AM, McCaffertty AE, Perrotta MM, Deszczpan M, fitterman D (2007a) Geophysical properties associated to Juá district geology, Ceará, Brazil. In: 10th International Congress of the Brazilian Geophysical Society, SBGf, Rio de Janeiro, April 2007, CD-Rom
Souza Filho OAde, McCaffertty AE, Silva AM, Perrotta MM (2007b) Ground-water potential: a predictive model from airborne geophysical, radiometric, and remote sensing data, Ceará, Brazil. In: Simpósio Brasileiro de Sensoriamento Remoto (SBSR), 13, April 2007, Florianópolis, Brazil, pp 3593–3595, CD-ROM. Available at http://marte.dpi.inpe.br/col/dpi.inpe.br/sbsr@80/2006/11.15.17.35.52/doc/3593-3595.pdf. Cited 15 May 2007
Speed R (2002) Airborne geophysics for catchment management: why and where. Explor Geophys 33:51–56
Telford WM, Geldart LP, Sheriff RE, Keys DA (1984) Applied geophysics. Cambridge University Press, New York, pp 442–457
Veríssimo LS, Feitosa FAC (2002) As águas subterrâneas no Nordeste do Brasil. Região de Irauçuba - Estado do Ceará, Brasil [Groundwater in Northeast Brazil. Irauçuba Region–Stte of Ceará]. In: Congresso da Associação Internacional de Hidrogeologia, XXXII e Congresso da Associação Latino-Americana de Hidrologia Subterrânea, VI, 2002, Mar Del Plata, Argentina, pp 889–896, CD-Rom. Available at http://proasne.net/CongALHSUD_Liano.pdf. Cited 10 January 2010
Wackernagel H (1995) External drift. In: Multivariate geostatistics: an introduction with applications. Springer, Berlin, pp 190–200
Wynn F (2002) Evaluating groundwater in arid lands using airborne magnetic/EM methods: an example in the southwestern U.S. and northern Mexico. The Leading Edge 1(21):62–64
Acknowledgements
The authors thank the support of the Geological Survey of Brazil, the Brazilian Coordination of Higher Education and Graduate Training-CAPES (BEX-3688/05-4), the University of Campinas (where the first author conducted this research as part of his PhD degree), and the valuable contributions of Gregory Lee and Michael Friedel, researchers from the US Geological Survey, Denver, CO.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
de Souza Filho, O.A., Silva, A.M., Remacre, A.Z. et al. Using helicopter electromagnetic data to predict groundwater quality in fractured crystalline bedrock in a semi-arid region, Northeast Brazil. Hydrogeol J 18, 905–916 (2010). https://doi.org/10.1007/s10040-010-0582-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10040-010-0582-4