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CALIBRATION AND RELIABILITY IN GROUNDWATER MODELLING: Managing

Groundwater and the EnvironmentEdited by Yanxin Wang, Shemin Ge, Mary C. Hill & Chunmiao ZhengIAHS Publ. 341 (2011) ISBN 978-1-907161-15-5, 278 + x pp. Price £60.00

This peer-reviewed collection of papers was selected from the seventh conference in the ModelCARE series on Calibration and Reliability in Groundwater Modelling. The most important contributions are included here and deal with: – New advances and innovations in model calibration, model prediction,

sensitivity analysis, and uncertainty assessment– Parameterizing groundwater models– Construction, calibration, reliability and use of models designed to

address resources and environmental concerns– Modelling of CO2 sequestration and other groundwater model applications

Abstracts of the papers in this volume can be seen at:

www.iahs.info

http://www.iahs.info/

Preface

ModelCARE2009 was the 7th International Conference on Calibration and Reliability in Groundwater Modelling. It was held in Wuhan, China, on 20–23 September 2009 with the conference theme “Managing Groundwater and the Environment”. ModelCARE2009 was jointly organized by the International Commission for Groundwater (ICGW) of the International Association of Hydrological Sciences (IAHS) and the China University of Geosciences. Financial support was provided by the National Natural Science Foundation of China; China Geological Survey; the Xi'an Regional Center of China Geological Survey; and the International Research Center on Karst, Guilin, China.

ModelCARE2009 was a follow-up to previous successful conferences organized in association with IAHS in: The Hague, the Netherlands (1990); Golden, Colorado, USA (1996); Zurich, Switzerland (1999); Prague, Czech Republic (2002); The Hague, the Netherlands (2005); and Copenhagen, Denmark (2007).

Within the context of model calibration and reliability, the conference addressed various issues of groundwater quality and quantity, including recent advances in theories and methodologies of groundwater flow and transport modelling, applicability of various approaches to real-world problems, and needs for future development. This volume contains 43 papers selected from 143 manuscripts and abstracts submitted to ModelCARE2009 by researchers from 17 countries. These papers were selected by the editors according to the results of peer-review by the members of the Scientific Advisory Committee (SAC). The volume is organized according to the four main themes of the conference:– New advances and innovations in model calibration, model prediction, sensitivity

analysis, and uncertainty assessment– Parameterizing groundwater models– Construction, calibration, reliability and use of models designed to address resources and

environmental concerns– Modelling of CO2 sequestration and other groundwater model applications

We would like to acknowledge the assistance from the SAC members who contributed to the success of the conference. Most also helped improve the quality of this volume: – Corinna Abesser, British Geological Survey, UK; Vice-President of ICGW – Mary Anderson, University of Wisconsin-Madison, USA – Jianmei Cheng, China University of Geosciences – Wuhan, China – Giuseppe Gambolati, University of Padua, Italy – Jimmy Jiao, University of Hong Kong, China – Wolfgang Kinzelbach, ETH, Switzerland – Kang-Kun Lee, Seoul National University, South Korea – David Lerner, University of Sheffield, UK – Hailong Li, China University of Geosciences – Beijing, China– Shlomo Neuman, University of Arizona, USA – Eileen Poeter, Colorado School of Mines, USA – Henning Prommer, CSIRO, Australia – Hans Christian Refsgaard, Geological Survey of Denmark and Greenland, Denmark – Ed Sudicky, University of Waterloo, Canada – Ne-Zheng Sun, University of California-Los Angeles, USA

– Makoto Taniguchi, Research Institute for Humanity and Nature, Japan; Vice-President of ICGW

– Georg Teutsch, UFZ Centre for Environmental Research, Germany – Dongguang Wen, China Geological Survey, China – Jichun Wu, Nanjing University, China – Tianfu Xu, LBNL, USA – Yuesuo Yang, Jilin University, China – William Yeh, University of California-Los Angeles, USA – Xun Zhou, China University of Geosciences – Beijing, China

Special thanks also go to Dr Yu Zhou, Dr Yiqun Gan and Ms Xinxin Guo of China University of Geosciences for their tremendous efforts in helping organize the conference.

Yanxin WangSchool of Environmental Studies

China University of Geosciences – WuhanWuhan 430074, China

Shemin GeDepartment of Geological Sciences

University of ColoradoBoulder, Colorado 80309, USA

Mary C. HillUS Geological Survey

Boulder, Colorado 80303, USA

Chunmiao ZhengDepartment of Geological Sciences

The University of AlabamaTuscaloosa, Alabama 35487, USA

The books of papers selected from earlier ModelCARE conferences and published by IAHS

Calibration and Reliability in Groundwater Modelling: Credibility of Modelling ModelCARE 2007edited by J. C. Refsgaard, K. Kovar, E. Haarder & E. Nygaard Publ. 320 (2008) ISBN 978-1-901502-49-7, 358 + x pp. £67.00

Calibration and Reliability in Groundwater Modelling: From Uncertainty to Decision Making ModelCARE 2005edited by M. F. P. Bierkens, J. C. Gehrels & K. KovarPubl. 304 (2006) ISBN 978-1-901-502-58-9; 316 + xii pp; £59.00

Calibration and Reliability in Groundwater Modelling: A Few Steps Closer to Reality ModelCARE 2002edited by K. Kovar & Z. Hrkal Publ. 277 (2003) ISBN 978-1-901502-07-7; 526 + x pp.; £78.80

Calibration and Reliability in Groundwater Modelling: Coping with Uncertainty ModelCARE 99edited by F. Stauffer, W. Kinzelbach, K. Kovar & E. HoehnPubl. 265 (2000) ISBN 978-1-901502-36-7; 524 + xii pp.; now £15.00

ModelCARE 96, Calibration and Reliability in Groundwater Modelling edited by Karel Kovar & Paul van der HeijdePubl. 237 (1996) ISBN 0-947571-94-9; 606 + x pp.; now £15.00

ModelCARE 90, Calibration and Reliability in Groundwater Modelling (the first in the series) edited by Karel KovarPubl. 195 (1990) ISBN 0-947571-67-1; 540 + xii pp.; now £15.00

Contents

Preface by Yangxin Wang, Shemin Ge, Mary C. Hill & Chunmiao Zheng iii

1 New advances and innovations in model calibration, model prediction, sensitivity analysis and uncertainty assessment

An operational drought forecasting system using coupled models for groundwater, surface water and unsaturated zone Wilbert Berendrecht, Albrecht Weerts, Ab Veldhuizen & Timo Kroon

3

Karst spring discharge modelling based on grey system theory: A case study at Shentou, northern China Qinghai Guo, Yanxin Wang & Teng Ma

9

The effects of trend and outliers on geostatistical analysis of hydraulic conductivity Xiao-Wei Jiang, Li Wan & Xu-Sheng Wang

14

Full-Bayesian, simple zoned inversion and transmissivity assessment of the Edwards Aquifer, Texas, USA Yefang Jiang & Allan D. Woodbury

21

Uncertainty analysis of an integrated hydrological model using posterior covariance matrix from automatic calibration Haitao Li, Wolfgang Kinzelbach, Harrie-Jan Hendricks Franssen, Philip Brunner & Albrecht Von Boetticher

27

Risk analysis of groundwater pollution X. Y. Ma & K. Wu 34

An objective-oriented pilot point method for identifying spatially variable hydraulic parameters Ne-Zheng Sun

40

Uncertainty of mass discharge estimates from contaminated sites using a fully Bayesian framework Mads Troldborg, Wolfgang Nowak, Philip J. Binning, Poul L. Bjerg & Rainer Helmig

46

Can we calibrate a complex groundwater model just by running an automatic calibration code? A case study from Italy: the Acque Albule Plain model (Rome) Francesco La Vigna, Rudy Rossetto, Roberto Mazza & Giuseppe Capelli

51

Numerical analysis and visualization of uncertainty effects in thermo-hydro-mechanical coupled processes in a hot-dry-rock geothermal reservoir Norihiro Watanabe, Björn Zehner, Wenqing Wang, Christopher I. Mcdermott, Takeo Taniguchi & Olaf Kolditz

57

Advances in basin-scale groundwater modelling in China Dongguang Wen, Eryong Zhang, Zhonghua Tang, Liangjun Lin, Li Wan, Chongxi Chen, Jingli Shao, Yongsheng Zhao, Wenke Wang, Hui Qian & Wenpeng Li

63

Optimization of a complex and highly parameterized groundwater system Beiyan Zhang, Daron G. Abbey, Paul J. Martin, Scott C. James, William W. Woessner, Richard G. Andrachek, Christian Gabriel & Bill W. Arnold

70

2 Construction, calibration, reliability and use of models designed to address resources and environmental concerns

Modelling the hydrological response of prairie pothole water bodies to climate variability Ganming Liu, Franklin W. Schwartz, Bo Zhang & Zhongbo Yu

79

Modelling of the groundwater–surface water system of the Maozui area of Jianghan Plain, central China Yu Zhou, Yanxin Wang, François Zwahlen & Julie Boillat

89

The impact of geothermal water exploitation on groundwater quality in Quaternary aquifers at Duncun in China Y. Q. Gan, X. X. Guo & Y. X. Wang

97

Compartment approach for regional hydrological analysis: application to the Meijiang catchment Feng Sun, Cui Chen, WenQing Wang, YaJie Wu, GeYing Lai & Olaf Kolditz

102

Application of the Multiscale Finite Element Method to the numerical modelling of regional groundwater systems Shujun Ye, Yuqun Xue, Jichun Wu, Zixin Wei & Qinfen Li

109

How can large-scale integrated surface–subsurface hydrological models be used to evaluate long-term climate change impact on groundwater reserves? Pascal Goderniaux, Serge Brouyère, Hayley J. Fowler, Stephen Blenkinsop, René Therrien, Philippe Orban & Alain Dassargues

115

Numerical modelling of physical clogging during groundwater artificial recharge Ying Lu, X. Q. Du, B. M. Chi, Y. S. Yang & W. Fan

121

A management model to control contaminant mass loading and pumping rates for sustainable groundwater use Dong Kyu Park, Gwang-Ok Bae & Kang-Kun Lee

127

Three-dimensional numerical simulation of impacts of urbanization on groundwater flow and salt transport in a coastal aquifer system, Busan, Republic of Korea Hyeon-Jo Cho & Jun-Mo Kim

133

3 Parameterizing groundwater models

Modelling field-scale uranium mass transfer at the Hanford IFRC site R. Ma, C. Zheng, H. Prommer & J. Greskowiak

141

Numerical modelling of flowing artesian wells using a well index method Xu-Sheng Wang

147

Mobile–immobile model of solute transport through porous and fractured media Zhou Chen, Jiazhong Qian, Hongbin Zhan, Luwang Chen & Shaohe Luo

154

MTBE attenuation in a dual porosity chalk aquifer – field observations and modelling results Lirong Cheng, David Lerner, Steve Thornton & K. Ulrich Mayer

159

An Euler-Lagrange approach to transport modelling in coupled hydrosystems J.-O. Delfs, C.-H. Park & O. Kolditz

166

Simulation of contaminant transport for contamination risk assessment Irina Galitskaya, Irina Pozdniakova & Leonid Toms

172

Numerical groundwater flow modelling for remediation design and seawater intrusion assessment at a coastal industrial site Andrea Gigliuto, Chiara Righetti, Arianna Chini & Rudy Rossetto

179

Three-dimensional numerical simulation of groundwater flow, salt and radionuclide transport at a proposed radioactive waste disposal site in Gyeongju, Republic of Korea. Chan-Sung Oh & Jun-Mo Kim

184

Development of a numerical model for radial collector well hydraulics and its application to riverbank filtration Eunhee Lee, Jiyoun Shin, Yunjung Hyun & Kang-Kun Lee

190

The role of porosity for transport block-upscaling in a clay-rich sedimentary formation Matthias Willmann, Wolfgang Kinzelbach & Fritz Stauffer

196

Optimization of groundwater pumping considering land subsidence in the Yangtze Delta, China X. B. Zhu, J. C. Wu, J. F. Wu & S. J. Ye

201

Estimation of the leak term and sensitivity analysis at a LUST groundwater system under data scarcity Jianfeng Wu, Jichun Wu & Xiaobin Zhu

207

4 Modelling of CO2 sequestration and other groundwater model applications

Numerical simulation of potential effects of CO2 leakage on shallow potable aquifers L. Jiang, Y. L. Li, W. Zhang & G. B. Qiu

215

Numerical simulation of impacts of mineralogical compositions on trapping mechanisms and efficiency of carbon dioxide injected into deep saline formations Jung-Hwi Kihm & Jun-Mo Kim

221

Numerical simulation of two-phase flow in deformable porous media: application to carbon dioxide storage in the subsurface Olaf Kolditz, Norbert Böttcher, Sebastian Bauer, Uwe-Jens Görke, Chan-Hee Park & Wenqing Wang

228

Validation of reactive transport models for co2 geological sequestration using TOUGHREACT Tianfu Xu

235

Modelling basin- and plume-scale processes of CO2 storage: a full-scale deployment scenario in the Illinois Basin Quanlin Zhou & Jens T. Birkholzer

239

Simulation of land subsidence caused by groundwater exploitation in the Hangzhou-Jiaxing-Huzhou Plain, South China Guoliang Cao, Chunmiao Zheng, Jiankang Zhao & Mengjie Wu

245

The role of aquifer heterogeneity in the anthropogenic uplift of Venice M. Ferronato, G. Gambolati & P. Teatini

252

Using numerical modelling to study groundwater circulation patterns in the Cretaceous Basin, China Lihe Yin, Guangcai Hou, Fusheng Hu & Guoliang Cao

258

Chlorinated ethene plume migration in groundwater at free-phase petroleum sites Edward McBean

262

Monitoring of aquifer pump tests with Magnetic Resonance Sounding (MRS): a synthetic case study D. Herckenrath, E. Auken & P. Bauer-Gottwein

267

Key-word Index 273

___________________________________________________________________________Managing Groundwater and the Environment (Proceedings of ModelCARE 2009, Wuhan, China, September 2009). IAHS Publ. 341, 2011, 3-8.

An operational drought forecasting system using coupled models for groundwater, surface water and unsaturated zone

WILBERT BERENDRECHT1, ALBRECHT WEERTS2, AB VELDHUIZEN3 & TIMO KROON4

1Deltares, PO Box 85467, 3508 AL Utrecht, The Netherlands2 Deltares, PO Box 177, 2600 MH Delft, The Netherlands

[email protected] Alterra-Wageningen UR, PO Box 47, 6700 AA Wageningen, The Netherlands4 Dutch Centre for Water Management (WMCN), PO Box 17, 8200 AA Lelystad, The Netherlands

Abstract During periods of drought the National Coordinating Committee for Water Distribution of the Netherlands has to decide how the available surface water is used and allocated between different functions. To support decision making, real-time and near-future information is needed about the availability of surface water, groundwater levels, saturation of the root zone, etc. For this purpose an operational drought forecasting system has been implemented. This system runs on a daily basis and provides nationwide distributed model estimates and forecasts of hydrological variables, based on a surface water model coupled with a MODFLOW-MetaSWAP model of the saturated–unsaturated zone. Model forcing includes radar data of actual precipitation and point measurements of actual evaporation. Model forecasts are driven by precipitation and evaporation from the Ensemble Prediction System. The system is operationalised within DELFT-FEWS, which is an operational forecasting system to manage data and models in a real-time environment.Key words drought; operational forecasting; distributed model; model coupling; the Netherlands


Karst spring discharge modelling based on grey system theory: A case study at Shentou, northern China

QINGHAI GUO, YANXIN WANG & TENG MASchool of Environmental Studies, China University of Geosciences, Wuhan 430074, [email protected]

Abstract As the most important water supply source for Shuozhou City of northern China, the Shentou springs have an average annual discharge of 6.86 m3/s. However, the discharge of the springs has been reducing since the early 1960s. Grey system theory is applied to simulate and predict the change in discharge of the Shentou springs with time. The change in the discharge of the Shentou springs can be divided into two phases: before and after 1985. The GM (1,1) model is used to fit the discharge change process before 1985, and grey prediction-amending model to simulate the process after 1985 and to predict the trend of the change. The prediction of discharge change between 2000 and 2004 shows that the discharge would follow the trend of increasing in the future should the rainfalls at Shentou continue to be comparatively high, as in the middle of the 1990s, and groundwater in Shuozhou is not excessively exploited.Key words Shentou karst springs; discharge attenuation; grey system theory; prediction

___________________________________________________________________________

Managing Groundwater and the Environment (Proceedings of ModelCARE 2009, Wuhan, China, September 2009). IAHS Publ. 341, 2011, 14-20.

The effects of trend and outliers on geostatistical analysis of hydraulic conductivityXIAO-WEI JIANG, LI WAN & XU-SHENG WANGSchool of Water Resources and Environment, China University of Geosciences, Beijing 100083, [email protected]

Abstract The geostatistical characterization of hydraulic conductivity heterogeneity has been a hot research topic. In this study, the hydraulic conductivity measurements along two sections at the Borden aquifer are utilized for analysis. The effect of outliers on the normality of log hydraulic conductivity (lnK) is discussed using histograms and probability plots, and the trends of hydraulic conductivity are identified using multivariate or univariate regression analysis. After removing the trends from lnK, the normality of the residual of lnK is discussed. Finally, vertical experimental variograms are calculated from lnK, the residual of lnK, and the residual of lnK without outliers. It is found that the residuals, after removal of trends, are suitable for calculation of variograms, and removal of outliers could result in smoother experimental variograms.Key words hydraulic conductivity; trend; outlier; lognormal; probability plot; variogram; Borden aquifer


Full-Bayesian, simple zoned inversion and transmissivity assessment of the Edwards Aquifer, Texas, USA

YEFANG JIANG1 & ALLAN D. WOODBURY2

1Department of Environment, Forestry and Energy of Prince Edward Island, 11 Kent St, Charlottetown, Prince Edward Island C1A 7N8, [email protected]

2Department of Civil Engineering, The University of Manitoba, 15 Gillson St, Winnipeg, Manitoba R3T 5V6, Canada

Abstract An alternative approach for transmissivity (T) estimation based on hierarchical-Bayesian and Maximum Entropy methods is presented. A stochastic conceptual framework is adopted for the aquifers in question and perturbation techniques are utilized to render a coupled non-linear problem into a linear one. Bayesian updating is used to condition prior estimates of logarithm T [ln(T)] with T measurements; then hydraulic head measurements are incorporated into the updating procedure by adopting a linearized flow equation. This approach was applied to estimate the ln(T) field of the Edwards Aquifer. Simulations with a simple zoned ln(T) distribution were also performed. Simulations showed the head fits alone might not provide enough information to judge what parameter estimation approach is superior to the other and which estimated field approximates reality better; but the T field from Bayesian inversion is of higher resolution, and respects the geology and spring discharges better than the estimation from PEST.Key words Bayes; transmissivity; stochastic inversion


mailto:[email protected]

Uncertainty analysis of an integrated hydrological model using posterior covariance matrix from automatic calibration

HAITAO LI1,5, WOLFGANG KINZELBACH1, HARRIE-JAN HENDRICKS FRANSSEN2, PHILIP BRUNNER3 & ALBRECHT VON BOETTICHER4

1 Institute of Environmental Engineering (IfU), ETH Zurich, CH-8093 Switzerland2 Institute for Chemistry and Dynamics of the Geosphere, Forschungszentrum Jülich GmbH, Leo Brandtstrasse,

Jülich, D-52425, Germany

3Centre d'Hydrogéologie et de Géothermie, University of Neuchatel, CH-2009 Switzerland4Swiss Federal Institute for Forest, Snow and Landscape Research, CH-8903 Switzerland5Now at: China Institute of Geo-Environmental Monitoring, Beijing 100081, China

Abstract This study quantifies the output uncertainties of an integrated hydrological model in the Yanqi Basin, Xinjiang, China. Two cases of model calibration were carried out: Case 1 used four parameters for calibration; Case 2: added fifteen more parameters for calibration. In both cases, hydraulic heads and evaporation patterns from NOAA images were used as conditioning information. In Case 1, no pair of adjustable parameters is highly correlated (highest R: 0.48). In Case 2, several pairs of adjustable parameters are highly correlated (highest R: 0.79). To analyse uncertainty, 5000 parameter realizations were generated using the optimized values and posterior covariance matrix from the model calibration cases. The impact of parameter uncertainty on seven selected model predictions is evaluated. The results show that the uncertainty is underestimated in Case 1. Therefore, it is advisable to include as many as possible adjustable parameters in the model calibration for parameter uncertainty analysis. In this way, it allows scanning of a much larger space of feasible solutions, although generally the calibration tries to use the “parsimony” principle.Key words uncertainty analysis; integrated hydrological model; posterior covariance matrix; random generation


Risk analysis of groundwater pollution

X. Y. MA & K. WUSchool of Civil & Hydraulic Engineering, Shandong University, Jinan 250061, [email protected]

Abstract To assess the risk of groundwater contamination quantitatively, a coupled groundwater flow and mass transport model of the site is needed. Due to the heterogeneity of the aquifer and the uncertainties in model input data, accurately modelling the contaminant transport process is very difficult. The uncertainty of model prediction may be caused by the uncertainties in model structure, model parameters as well as the assumption of boundary conditions. In this study, we use the Monte-Carlo Simulation (MCS) technique to estimate the probability of failure for risk analysis. We employ this model to investigate the contamination risk of Jinan, in China. The sampling region is determined from the results of groundwater flow model calibration and statistical analysis. According to the study, the time required for contaminant to exceed a target level at the centre of the city is predicted. Sensitivity of the probability of failure to basic uncertainty in conductivity and recharge is also obtained.Key words groundwater transport; risk analysis; uncertainty; sensitivity; Jinan, China


An objective-oriented pilot point method for

identifying spatially variable hydraulic parameters NE-ZHENG SUN1,2

1School of Civil Engineering, Shandong University, Jinan, Shandong province, China 2Department of Civil & Environmental Engineering, University of California, Los Angeles, USA

[email protected]

Abstract In this paper, the objective-oriented method of model construction is extended from the deterministic framework to the statistical framework. The new methodology incorporates the objectives of the model application and its accuracy requirements into the model construction process directly. It can answer how complex the conceptual model should be and how many data are sufficient for model calibration. An objective-oriented pilot point method is then developed, in which the number of pilot points is increased gradually and their locations are optimized. A numerical example is given. Key words groundwater modelling; inverse problem; parameter estimation; pilot point method; geostatistics; model uncertainty


Uncertainty of mass discharge estimates from contaminated sites using a fully Bayesian framework

MADS TROLDBORG1, WOLFGANG NOWAK2, PHILIP J. BINNING1, POUL L. BJERG1 & RAINER HELMIG2

1Department of Environmental Engineering, Technical University of Denmark, Miljoevej B113, DK-2800 Kgs. Lyngby, [email protected]

2 Institute of Hydraulic Engineering, Universität Stuttgart, Pfaffenwaldring 61, D-70569 Stuttgart, Germany

Abstract Mass discharge estimates are increasingly being used in the management of contaminated sites and uncertainties related to such estimates are therefore of great practical importance. We present a rigorous approach for quantifying the uncertainty in the mass discharge across a multilevel control plane. The method accounts for: (1) conceptual model uncertainty through Bayesian model averaging, (2) heterogeneity through Bayesian geostatistics with an uncertain geostatistical model, and (3) measurement uncertainty. An ensemble of unconditional steady-state plume realizations is generated through Monte Carlo simulation. By use of the Kalman Ensemble Generator, these realizations are conditioned on site-specific data. Hereby a posterior ensemble of realizations, all honouring the measured data at the control plane, is generated for each of the conceptual models considered. The ensembles from different conceptual models are combined via Bayesian model averaging, yielding the overall mass discharge probability distribution. Method features are illustrated on a synthetic test case.Key words mass discharge; uncertainty quantification; Kalman Ensemble Generator; groundwater contamination; Bayesian inference


Can we calibrate a complex groundwater model just by running an automatic calibration code? A case study from Italy: the


Acque Albule Plain model (Rome)

FRANCESCO LA VIGNA1, RUDY ROSSETTO2, ROBERTO MAZZA1 & GIUSEPPE CAPELLI1

1RomaTRE University, LinQ - Numerical and Quantitative Hydrogeology Lab, Largo S. Leonardo Murialdo, 1, 00146 Rome, Italy [email protected]

2Sant’Anna School of Advanced Studies - Land Lab, Piazza Martiri della Libertà, 1-33-56127 Pisa, Italy

Abstract This note presents a calibration of a model of a complex groundwater system located in central Italy, in the subsiding Acque Albule (AA) Plain near Rome (Italy). There are two main aquifers in this system. The first is the limestone fractured bedrock, partially confined by Pliocene-Pleistocene deposits, while the second one is within the fractured travertine and is unconfined. These two aquifers are hydraulically connected in correspondence of the centre of the plain, where deep hydrothermal water upwells from the limestone bedrock through the Plio-Pleistocene deposits into the travertine. The AA groundwater model is applied to a 55-km2 area and is developed by using MODFLOW-2005, discretized by 100 m 100 m cells and three layers. The calibration process applied to this model consists of several steps using estimation methods along with sensitivity analysis and geological information. The final model fit shows the importance not only of applying automatic estimation methods for calibration processes, but also the need to change the conceptual model and collect new data to understand the system better.Key words groundwater model calibration; sensitivity analysis; geological information; MODFLOW-2005; UCODE-2005; Italy


Numerical analysis and visualization of uncertainty effects in thermo-hydro-mechanical coupled processes in a hot-dry-rock geothermal reservoir

NORIHIRO WATANABE1,2, BJÖRN ZEHNER1, WENQING WANG1, CHRISTOPHER I. MCDERMOTT3, TAKEO TANIGUCHI4 & OLAF KOLDITZ1,2

1Department of Environmental Informatics, UFZ - Helmholtz Centre for Environmental Research, Permoserstrasse 15, D-04318 Leipzig, [email protected]

2Dresden University of Technology, Applied Environmental Analysis, Helmholtzstrasse 10, D-01069 Dresden, Germany

3Edinburgh Collaborative of Subsurface Science and Engineering (ECOSSE), School of Geoscience, University of Edinburgh Scotland, UK

4Graduate School of Environmental Science, Okayama University, Japan

Abstract We present an uncertainty analysis of thermo-hydro-mechanical (THM) coupled processes in a typical hot-dry-rock reservoir in crystalline rock. The conceptual model is an equivalent porous media approach which is adequate for available data from the Urach Spa and Falkenberg sites (Germany). The finite element method (FEM) is used for the numerical analysis of fully coupled THM processes, including thermal water flow, advective-diffusive heat transport, and thermo-poro-elasticity. Reservoir parameters are considered as spatial random variables and their realizations are generated using conditional Gaussian simulation. The results show the influence of parameter ranges on the reservoir evolution during long-term heat extraction taking into account fully coupled THM processes. We found that the most significant factors are permeability and heat capacity variations. The study demonstrates the importance of taking parameter uncertainties into account for geothermal reservoir evaluation in order to assess the predictability of numerical modelling.


Key words hot-dry-rock geothermal reservoir; uncertainty analysis; thermo-hydro-mechanical coupled processes; Monte-Carlo simulation; visualization


Advances in basin-scale groundwater modelling in China

DONGGUANG WEN1, ERYONG ZHANG1, ZHONGHUA TANG2, LIANGJUN LIN1, LI WAN3, CHONGXI CHEN3, JINGLI SHAO3, YONGSHENG ZHAO4, WENKE WANG5, HUI QIAN5 & WENPENG LI6

1China Geological Survey, 45 Fuwai Street, Xicheng District, Beijing 100037, [email protected]

2China University of Geosciences, Wuhan 430074, China3China University of Geosciences, Beijing 100083, China4Jilin University, Changchun 130026, China5Chang’an University, Xi’an 710064, China6China Institute of Geo-environmental Monitoring, Beijing 100081, China

Abstract This paper introduces some of the major developments in basin-scale groundwater flow modelling in China. Since the 1970s groundwater modelling has been used to evaluate groundwater resources and relevant environmental issues in China. In the early stage, the simulation area was usually small due to the limitation of computer technology. From 1999, investigations of groundwater resources and related environmental issues have been performed and organized by the China Geological Survey. GIS-based databases and groundwater flow models have been developed for the main basins and plains to evaluate and exploit the groundwater resources. GMS, FEFLOW and Visual MODFLOW are used to construct the geological models and groundwater flow models. A seepage-pipe flow model has been proposed to simulate groundwater flow in porous-fissured-caved media, artesian wells and spring fluxes. New software, PGMS (Polygon grid finite-difference Groundwater Modelling System), has been developed and used for basin-scale groundwater modelling.Key words groundwater; numerical modelling; basin-scale; China


Optimization of a complex and highly parameterized groundwater system

BEIYAN ZHANG1, DARON G. ABBEY1, PAUL J. MARTIN1, SCOTT C. JAMES2, WILLIAM W. WOESSNER3, RICHARD. G. ANDRACHEK4, CHRISTIAN GABRIEL1 & BILL W. ARNOLD2

1AquaResource Inc., 55 Northfield Dr. East. – Suite 203, Waterloo, Ontario N2K 3T6, [email protected]

2Sandia National Laboratories, USA3Department of Geosciences, University of Montana, USA 4MWH Global, USA

Abstract Groundwater flow predictions in complex geological environments require the use of models that represent an appropriate number of potentially important physical features. Oversimplification of the flow system may neglect features that are important to understanding the range of possible flow predictions. The Singular Value Decomposition and Tikhonov Regularization techniques implemented

in the SVD-Assist tool within PEST enabled optimization of complex and highly parameterized models. These techniques are applied to a finite-element flow model that has 46 layers and 1245 adjustable parameters supported by 302 point observations of heads, head differences, pumping rates and seepage flow. Optimization improved the model fit significantly as the objective function was reduced by 80% from its initial value. The optimized model retains sufficient parameter detail to predict flow directions. Key words parameter estimation; SVD-Assist; objective function


Modelling the hydrological response of prairie pothole water bodies to climate variability

GANMING LIU1, FRANKLIN W. SCHWARTZ1, BO ZHANG1 & ZHONGBO YU2

1 School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, [email protected]

2Department of Geoscience, University of Nevada Las Vegas, Las Vegas, Nevada 89154, USA

Abstract This paper describes a hydrological model that can simulate a surface-water complex comprised of tens-of-thousands or more closed-basin pothole lakes and wetlands in the Prairie Pothole Region of Canada and the USA. This model incorporates a novel system for calibration that uses observed area–frequency power-law relationships for tens-of-thousands of water bodies, as well as water depths in individual water bodies, and a probabilistic modelling procedure to provide the 100-year response of a pothole complex through numerous periods of drought and deluge. Simulations show that over the last century major droughts and deluges created one to two orders-of-magnitude variability in the intercept of power laws on water area. Climate extremes varied from drought (Dust Bowl drought) to a deluge beginning in 1993. With pothole water bodies, groundwater has the potential to significantly impact surface water budgets, especially during dry periods.Key words climate; hydrological model; lake; wetland; power law; lake area; Prairie Pothole Region


Modelling of the groundwater–surface water system of the Maozui area of Jianghan Plain, central China

YU ZHOU1,2, YANXIN WANG1, FRANÇOIS ZWAHLEN2 & JULIE BOILLAT2

1School of Environmental Studies and MOE Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, [email protected]

2 Center of Hydrogeology, University of Neuchâtel, CH-2009 Neuchâtel, Switzerland

Abstract The objective of this study is to get a better understanding of the local groundwater–surface water system at a typical site of the Jianghan plain of central China, in the vicinity of Maozui, and eventually to give a perspective in order to understand the regional hydrogeological system of Jianghan Plain. Conceptual and analytical models were established before using FEFLOW software for modelling. Models were elaborated and improved with information notably about the aquifer’s physical configuration and the elevation of piezometric levels. The results show that piezometric level forms a dome in the middle of the meander and groundwater flows radially from there to the river with a flux of 4.62 103 m3/d across the boundaries.Key words groundwater; modelling; FEFLOW; river; piezometric level




The impact of geothermal water exploitation on groundwater quality in Quaternary aquifers at Duncun in China

Y. Q. GAN, X. X. GUO & Y. X. WANGSchool of Environmental Studies and MOE Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, [email protected]

Abstract The over exploitation of geothermal water in Duncun, China, has a considerable environmental impact on groundwater in Quaternary aquifers. This paper discusses the hydrogeochemical characteristics of the geothermal water and groundwater. Special emphasis is put on the study of the impact of the exploitation of geothermal water on groundwater in Quaternary aquifers. The chemical analysis indicates an obvious mixing process in Duncun geothermal field, which is the dominant process that degraded the groundwater quality and resulted in the prevailing undersaturation state of groundwater samples with respect to minerals.Key words thermal water; groundwater quality; Duncun; Xinzhou basin; saturation index


Compartment approach for regional hydrological analysis: application to the Meijiang catchment, China

FENG SUN1,2, CUI CHEN2, WENQING WANG1, YAJIE WU1, GEYING LAI3 & OLAF KOLDITZ1,2

1Department of Environmental Informatics, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, D-04318 Leipzig, [email protected]

2Dresden University of Technology, Applied Environmental Analysis, Helmholtzstraße 10, D-01069 Dresden, Germany

3School of Geography and Environment, JiangXi Normal University, Ziyang Road 99, 330022 Nanchang, China

Abstract The presented methodology for regional soil water analysis was originally developed for Beerze-Reusel drainage basin in the southern part of the Netherlands. We further develop this methodology for hydrological modelling in particular combining GIS-based structural 3-D modelling with data management as a pre-processing tool for the finite element analysis of hydrosystems. The 3-D structural modelling is based on typical geological layer information. The topography of all geological layers is represented by contour maps based on which stratified finite element meshes are mapped successively. The second new development is the integration of GIS database information into the finite element analysis within the scientific OpenGeoSys (OGS) software. Thus, for example, information about complex soil systems can be incorporated into the set-up of the corresponding finite element model for the soil compartment. As an application, we present a case study for the Meijiang area with the focus on surface/subsurface water interaction and the recharge response from surface infiltration to groundwater with different time series discretization. The numerical model was implemented within the framework of object-oriented programming. Key words compartment approach; coupled hydrosystems; regional hydrologic soil model (RHSM); GeoHydro/DataBase (GHDB); Meijiang catchment, China; Poyang Lake basin


Application of the Multiscale Finite Element Method to the numerical modelling of regional groundwater systems

SHUJUN YE1, YUQUN XUE1, JICHUN WU1, ZIXIN WEI2 & QINFEN LI2

1State Key Laboratory of Pollution Control and Resource Reuse, Department of Hydrosciences, Nanjing University, Nanjing 210093, [email protected]

2 Shanghai Institute of Geology Survey, Shanghai 200072, China

Abstract A new finite element method, the multiscale finite element method (MsFEM), applied to resolve large regional groundwater flow models is introduced. Two advantages make the MsFEM useful for flow simulation in large regions with highly heterogeneous porous media. One is that this method can significantly save computing efforts. Parameters in an element can vary in MsFEM, and the variation in parameters is incorporated into the base functions. Thus a coarse grid can describe the variation in parameters, which results in less computing resources for a large regional groundwater flow model. The other is that this method can, to a large extent, avoid the deformation of elements. This is especially important for the numerical simulation of large-scale regional groundwater flow problems, where the horizontal extents are usually much greater than the vertical extents. MsFEM is applied to model the groundwater flow system in Shanghai.Key words multiscale finite element method; numerical modelling; regional groundwater flow


How can large-scale integrated surface–subsurface hydrological models be used to evaluate long-term climate change impact on groundwater reserves?

PASCAL GODERNIAUX1,2, SERGE BROUYÈRE1, HAYLEY J. FOWLER3, STEPHEN BLENKINSOP3, RENÉ THERRIEN4, PHILIPPE ORBAN1 & ALAIN DASSARGUES1

1Group of Hydrogeology and Environmental Geology – Aquapôle, University of Liège, Chemin des Chevreuils, 1, B52/3, B-4000 Liège, [email protected]

2Funds for Scientific Research - FNRS, Rue d’Egmont, 5, B-1000 Brussels, Belgium3Water Resource Systems Research Laboratory - School of Civil Engineering and Geosciences, Newcastle

University, Newcastle upon Tyne NE1 7RU, UK4Department of Geology and Geological Engineering, Université Laval, Quebec G1K 7P4, Canada

Abstract Estimating the impacts of climate change on groundwater represents one of the most difficult challenges faced by water resources specialists. One difficulty is that simplifying the representation of the hydrological system often leads to discrepancies in projections. This study provides an improved methodology for the estimation of the impacts of climate change on groundwater reserves, where a physically-based surface–subsurface flow model is combined with advanced climate change scenarios for the Geer basin (465 km2), Belgium. Integrated surface–subsurface flow is simulated with the finite

element model HydroGeoSphere. The simultaneous solution of surface and subsurface flow equations in HydroGeoSphere, as well as the internal calculation of actual evapotranspiration, improve the representation of interdependent processes like recharge, which is crucial in the context of climate change. Climate change simulations were obtained from six regional climate model (RCM) scenarios downscaled using a quantile mapping bias-correction technique that, rather than applying a correction only to the mean, also applies a change in the distribution of wet and dry days. For the climatic scenarios considered, the integrated flow simulations show that significant decreases are expected in the groundwater levels and in the surface water flow rates by 2080.Key words groundwater; climate change; integrated modelling; HydroGeoSphere; Geer basin, Belgium

___________________________________________________________________________Managing Groundwater and the Environment (Proceedings of ModelCARE 2009, Wuhan, China, September 2009). IAHS Publ. 341, 2011,121-126.

Numerical modelling of physical clogging during groundwater artificial recharge

YING LU1, X. Q. DU1, B. M. CHI2,1, Y. S. YANG1,3 & W. FAN1

1College of Environment and Resources, Jilin University, Changchun 130026, [email protected]

2 Institute of Disaster Prevention Science and Technology, Beijing 101601, China3School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3YE, UK

Abstract Groundwater artificial recharge, a promising method for sustainable water management, is often limited by the clogging problem. A predictive dynamic model linking the hydrodynamics with the spatial-temporal distribution of the fine particles deposition was developed to realize a quantitative understanding of the clogging process. The model is based on the mass balance equations for liquid and suspended solids. It combines three main equations to simulate the process of physical clogging: the flow dynamics equation, and the simultaneous transport equation and kinetic equations of the fine particles. These equations were incorporated into a finite element model for the simulation of the clogging process. A case study is presented for a site in the Pinggu district of Beijing, China. With the parameters obtained from the laboratory column experiments, the model was applied to assess the risk of physical clogging during artificial recharge using local storm water in the study area.Key words artificial recharge; clogging; dynamic modelling; particle deposition


A management model to control contaminant mass loading and pumping rates for sustainable groundwater use

DONG KYU PARK, GWANG-OK BAE & KANG-KUN LEESchool of Earth and Environmental Sciences, Seoul National University, Seoul 151-747, Republic of [email protected]

Abstract A management model is developed to achieve sufficient groundwater supply and quality conservation together for sustainable groundwater use. It calculates the on-ground contaminant mass loading by integrating an analytical model for 1-D solute transport in the unsaturated zone and a 3-D groundwater flow and solute transport model. This integrated simulation model is linked to a genetic algorithm that searches for the global optimum for the optimal management design. The management design involves obtaining the optimal pumping rates that are able not only to supply groundwater sufficiently but also to prevent excessive drawdown and contamination. It also includes controlling the contaminant mass loading on the possible sources by suggesting the allowable limit. For this multi-


objective management, the objective function to maximize dual decision variables and the constraints for drawdown and concentration are assigned in the optimization model. The proposed management methodology is applicable and efficient for providing groundwater management options.Key words management model; contaminant mass loading; pumping rates; integrated simulation model; simulation-optimization model; genetic algorithm


Three-dimensional numerical simulation of impacts of urbanization on groundwater flow and salt transport in a coastal aquifer system, Busan, Republic of Korea

HYEON-JO CHO1 & JUN-MO KIM2

1Department of Civil Engineering and Environmental Sciences, Korea Military Academy, Seoul 139-799, Republic of Korea

2School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, Republic of [email protected]

Abstract A series of three-dimensional numerical simulations using a generalized multidimensional hydrodynamic dispersion numerical model was performed to simulate effectively and to evaluate quantitatively the impacts of urbanization on density-dependent groundwater flow and salt transport in a coastal aquifer system, Busan, Republic of Korea. A series of steady-state numerical simulations of groundwater flow and salt transport before urbanization with material properties of the geological media, which were established by model calibration considering all the urbanization factors, is performed first. A series of transient-state numerical simulations of groundwater flow and salt transport after urbanization is then performed considering the urbanization factors separately and all together. The results of the numerical simulations show that density-dependent groundwater flow, salt transport and seawater intrusion patterns in the coastal aquifer system are intensively and extensively impacted by the urbanization factors. However, such impacts of each urbanization factor are not spatially uniform but locally different.Key words coastal aquifer; urbanization; groundwater flow; salt transport; seawater intrusion; numerical simulation


Modelling field-scale uranium mass transfer at the Hanford IFRC site

R. MA1, C. ZHENG1, H. PROMMER2 & J. GRESKOWIAK2 1Department of Geological Sciences, University of Alabama, Tuscaloosa, Alabama 35487, USA

[email protected] Land and Water, Perth, Australia

Abstract The variation of geochemical conditions caused by Columbia River water intrusion combined with kinetic uranium adsorption/desorption behaviours observed in the laboratory suggest that a multi-rate surface complexation model (SCM) is needed to account for uranium transport at the 300 Area of the Hanford site in southeast Washington State, USA. This study incorporates the laboratory research results into a field-scale multi-rate SCM and investigates its application to a cross-section near the 300A site as part of the Integrated Field-Scale Subsurface Research Challenge (IFRC) programme supported by the US Department of Energy. The reactive transport simulation results indicate that the U(VI) plume is strongly adsorbed by aquifer sediments. Generally, river water intrusion enhances uranium adsorption by lowering the carbonate and increasing pH in groundwater. Employing the multi-rate SCM, U(VI) migration is much more dynamic and synchronic with the groundwater flow field. Even though the

general extent of the U(VI) plume does not change significantly after a certain time period, the plume’s high concentration zone remains quite dynamic. In contrast, in the simulations with an equilibrium-based SCM, the plume shows very limited seasonal movement. Overall, the results from the multi-rate SCM appear to be more consistent with the field observations of a dynamic uranium plume at the 300A site. Key words surface complexation reactions; multi-rate mass transfer; uranium transport; Hanford site, Washington, USA; reactive transport modelling


Numerical modelling of flowing artesian wells using a well index method

XU-SHENG WANGSchool of Water Resources & Environment, China University of Geosciences, Beijing 100083, China

Abstract A Well Index Method is proposed in numerical modelling of flowing artesian wells with the Block Centred Finite Difference Method. Linear and nonlinear well losses are considered. Using an analytical solution for an idealized situation, this method is verified to be efficient except in the early time after opening of the well, even though the scale of grid cells extends to 1000 m. Between two definitions of well index, the well index (WI-A) defined by van Poolen et al. (1968) and the well index (WI-B) defined by the equivalent radius (Prickett, 1967), WI-B yields a better result that approaches the exact solution. An alternative method, the Constant-Head Wellblock Method, is proved to be not successful. It is indicated that nonlinear well loss can reduce the flow rate of a flowing artesian well. Nonlinear correlation between total flow rate and the number of wells is found in well-group problems associated with a leaky confined aquifer.Key words groundwater; numerical modelling; well index; equivalent radius; confined aquifer


Mobile–immobile model of solute transport through porous and fractured media

ZHOU CHEN1, JIAZHONG QIAN1, HONGBIN ZHAN2, LUWANG CHEN1 & SHAOHE LUO3

1School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China [email protected]

2Department of Geology & Geophysics, Texas A&M University, College Station, Texas 77843-3115, USA3School of Resources and Environmental Engineering, Henan Polytechnic University, Jiaozuo 454100, China

Abstract Investigation of analytical models of solute transport is a key aspect in parameter identification at both the micro and field scales. The advection–dispersion equation (ADE) is commonly used to describe the movement of solute transport in porous media. However, increasing evidence indicates that the ADE model is problematic in describing transport in heterogeneous, fractured or even “homogeneous” media. In this paper, an alternative mobile–immobile (MIM) model is employed for describing solute transport in both porous and fractured media. Tracer experiments in porous and fractured media were carried out. The breakthrough curves (BTCs) were fitted by both the ADE and MIM models and results show that the MIM model does better than ADE in both porous and fractured media, especially in describing the peaks and long tails of the BTCs. The MIM model, which is physically sound, can explain the BTCs better in a rough-walled fracture than in a smooth-walled fracture.Key words ADE model; MIM model; porous and fractured media; tracer experiment


MTBE attenuation in a dual porosity chalk aquifer – field observations and modelling results

LIRONG CHENG1, DAVID LERNER2, STEVE THORNTON2 & K. ULRICH MAYER3

1College of Water Sciences, Beijing Normal University, 100875 Beijing, China2University Sheffield, Sheffield S3 7HQ, UK 3Department of Earth and Ocean Sciences, The University of British Columbia, V6T 1Z4, Canada

Abstract A simplified conceptual model of MTBE attenuation in a dual porosity chalk aquifer was built and validated using field observations and modelling. It was shown that dual porosity transport and mass transfer between the fractures and matrix plays an important role in MTBE attenuation in this aquifer . The concentration of MTBE measured in monitoring wells may depend more on dual porosity transport effects than biodegradation. For this dual porosity aquifer (the Chalk), with its large portion of immobile water, a single porosity model is not able to predict the plume evolution. The dual porosity model was able to accurately produce the quick response of fracture transport and the measured contaminant concentration at different distances and depths. Examination of MTBE fate with laboratory-measured MTBE biodegradation rates showed that MTBE is unlikely to biodegrade within the Chalk matrix. MTBE may be biodegraded in fractures with a maximum rate of 3.62 10-12 mol L-1 s-1. Physical processes such as advection, dispersion, diffusion and dual porosity mass transfer are more important than biodegradation in controlling plume development in this aquifer and should be considered in similar settings elsewhere.Key words chalk; MTBE; attenuation; dual porosity; model; degradation; mass transfer


An Euler-Lagrange approach to transport modelling in coupled hydrosystems

J.-O. DELFS1, C.-H. PARK1 & O. KOLDITZ1,2

1Department of Environmental Informatics, UFZ-Helmholtz Centre for Environmental Research, Permoserstrasse 15, D-04318 Leipzig, [email protected]

2Faculty of Forestry, Geosciences and Hydrosciences, Dresden Technical University, Helmholtzstrasse 10, D-01069 Dresden, Germany

Abstract Hydrosystems are very complex systems with numerous processes occurring simultaneously at different spatial and temporal scales. We present an Euler-Lagrange approach for the analysis of flow and transport processes in coupled hydrosystems. Hydrological processes are described by diffusion equations (the diffusive wave approximation for overland flow and Richards equation for flow in the unsaturated zone) and coupled with exchange fluxes. The governing equations of the flow processes are spatially discretized with Euler methods (finite elements, finite volumes). A new feature of this study is the use of Lagrangian stochastic particles (random walk particle tracking methods) for numerical investigation in coupled hydrosystems. This new model is applied to a laboratory experiment on the effects of the capillary fringe during streamflow generation. The numerical results agree well with the experimental data for a steady flow field.Key words coupled hydrosystem analysis; random walk particle tracking; Abdul & Gillham experiment; streamflow generation


Simulation of contaminant transport for contamination risk assessment

IRINA GALITSKAYA, IRINA POZDNIAKOVA & LEONID TOMSSergeev Institute of Environmental Geoscience of Russian Academy of Science (IEG RAS), Moscow, 10100, 13, Building 2, Ulansky per., [email protected]

Abstract Former disposal fields are considered now as new building construction areas in Moscow. Investigations show that the unsaturated zone under disposal fields was contaminated by heavy metals, nitrogen and organic compounds. No detailed work on groundwater contamination has been done. A stochastic-deterministic approach used for groundwater risk contamination assessment for a case without reliable information about the groundwater contamination is presented in this paper. The deterministic models include contaminant transport in the unsaturated zone and groundwater. The stochastic elements relate to “lithological” or “hydrogeological” windows in the aquitard which separates the upper contaminated aquifer and the lower target aquifer which is important for groundwater supply. Unsaturated flow and transport modelling was performed with WHI UnSat Suite Plus. Groundwater flow and contaminant transport were modelled using MODFLOW/MT3DMS codes. Stochastic conditional simulation was performed with the SISIM code of the GSLIB library. Results of the multiple forecasts have allowed estimation of the high probability of groundwater pollution of the target aquifer due to leakage from the upper aquifer through “lithological” windows in the aquitard.Key words disposal fields; groundwater; contamination; transport; aquifer; aquitard; risk; stochastic modelling


Numerical groundwater flow modelling for remediation design and seawater intrusion assessment at a coastal industrial site

ANDREA GIGLIUTO1, CHIARA RIGHETTI1, ARIANNA CHINI1 & RUDY ROSSETTO2

1AECOM Italy S.r.l., Via Francesco Ferrucci 17/A, I-20145 Milano, [email protected]

2Land Lab - Sant'Anna School of Advanced Studies, Via Santa Cecilia 3, I-56127 Pisa, Italy

Abstract A three-dimensional density-dependent groundwater flow and transport numerical model was implemented using the finite element code FEFLOW, to assess jointly seawater intrusion and the remediation strategy at a former gas plant site located along the coastline in southern Italy. The aim of the remediation project was to contain contaminated groundwater (contamination by arsenic and total petroleum hydrocarbons) movements out of the site, while avoiding seawater intrusion inland. The model demonstrated that installing a physical groundwater flow barrier would actually increase seawater intrusion at the site, and that the best remedial solution would be a coupled pumping–injection barrier. In fact, this remediation strategy would allow for effective containment of contaminated groundwater, while at the same time reducing seawater intrusion into the freshwater aquifer.Key words seawater intrusion; remediation strategy; coupled pumping–injection barrier

___________________________________________________________________________

Managing Groundwater and the Environment (Proceedings of ModelCARE 2009, Wuhan, China, September 2009). IAHS Publ. 341, 2011, 184-189.

Three-dimensional numerical simulation of groundwater flow, salt and radionuclide transport at a proposed radioactive waste disposal site in Gyeongju, Republic of Korea

CHAN-SUNG OH & JUN-MO KIMSchool of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, Republic of [email protected]

Abstract A series of steady-state and transient-state three-dimensional numerical simulations and calibration using a generalized multidimensional multicomponent hydrodynamic dispersion model is performed to predict and analyse groundwater flow and both salt and radionuclide transport at a proposed low and intermediate level radioactive waste disposal site, in Gyeongju, Republic of Korea. The results of the numerical simulations show that the hydrogeological characteristics of each anisotropic geological formation (porous rock matrix plus joint sets) are more dependent on the joint sets than the porous rock matrix, while the hydrogeological characteristics of the whole geological system (geological formations plus fracture zones) are even more controlled by the fracture zones than the geological formations. The results of the numerical simulations also indicate that both adsorption (retardation) and radioactive decay of the radionuclides play important roles in maximizing the efficacy of the surrounding geological formations as natural barriers and thus in minimizing the dispersion of the mother and daughter radionuclides from the proposed repository.Key words geological formations; fracture zones; low and intermediate level radioactive waste disposal; groundwater flow; salt transport; radionuclide transport; numerical simulation


Development of a numerical model for radial collector well hydraulics and its application to riverbank filtration EUNHEE LEE, JIYOUN SHIN, YUNJUNG HYUN & KANG-KUN LEESchool of Earth and Environmental Sciences, Seoul National Univ., PO Box 151-747, Bldg 25-1 Rm 505, Seoul National University, Seoul, [email protected]

Abstract A new numerical model for evaluation of the drawdown in horizontal arms of a radial collector well is presented. The model accounts for internal friction losses in the arms of the collector well, which depends on Reynolds number and pipe roughness. The proposed model was used to investigate flow response to pumping at a radial collector well in a riverbank filtration facility in Daesan-myeon, Korea. Simulation results were used to analyse the distribution of extracted water from each horizontal arm and the contribution of river water flux to the radial collector well. The estimated maximum drawdown and the ratio of filtered river water to that of total groundwater abstraction flux due to the pumping are 0.72 m and 51.8%, respectively. Results demonstrate that the proposed approach can be used as a practical tool for evaluating the efficiency of riverbank filtration radial collector wells.Key words horizontal well; radial collector well; numerical model; riverbank filtration; Korea


The role of porosity for transport block-upscaling in a clay-rich sedimentary formation

MATTHIAS WILLMANN, WOLFGANG KINZELBACH & FRITZ STAUFFERInstitute of Environmental Engineering, ETH Zurich, Wolfgang-Pauli-Str. 15, 8093 Zurich, Switzerland [email protected]

Abstract Large-scale numerical transport models are needed for many applications in hydrogeology. Known local-scale parameters have to be transferred to a larger numerical grid scale in order to model the large-scale behaviour correctly. Classical methods of upscaling do not alter the porosity of upscaled models. We study advective transport on successively (block-) upscaled 3-D heterogeneous hydraulic conductivity fields of a strongly heterogeneous formation. We analyse the resulting breakthrough curves and, particularly, the changes of early arrival times, which give us a measure of mobile porosity of the upscaled model. We find the early arrival time delayed when homogenizing the hydraulic conductivity field. To account for this delay the mobile porosity of the upscaled model has to be reduced. This is an indicator that multiple-rate mass transfer is an excellent tool for upscaling strongly heterogeneous aquifers. Key words transport models; upscaling; multiple-rate mass transfer; porosity


Optimization of groundwater pumping considering land subsidence in the Yangtze Delta, China

X. B. ZHU, J. C. WU, J. F. WU & S. J. YEState Key Laboratory of Pollution Control and Resources Reuse, Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, 210093 Nanjing, [email protected]

Abstract The Yangtze Delta is one of the most important regions for Chinese economic development. The sustainable development of this area relies heavily on the groundwater resources. Land subsidence, which is mainly due to the excessive pumping of deep groundwater, has become a serious geological hazard. A groundwater management tool is needed in order to avoid further development of land subsidence. Based on an existing 3-D flow model, a groundwater management model of deep aquifers was built taking the land subsidence into account. The management model takes the maximum total pumping rates as objective function, subject to the groundwater level at control points. The groundwater level at control points in each aquifer is converted by the cumulative land subsidence according to the regression equation between the cumulative land subsidence and the cumulative decline of groundwater level. Genetic Algorithm (GA) and Shuffled Complex Evolution-University of Arizona (SCE-UA) methods were used to solve the management model. The results show that the total pumpage of deep groundwater in the central areas of land subsidence in Changzhou-Wuxi, Suzhou and Jiaxing should be reduced from 991 370 m3/d to about 460 000 m3/d (the pumping rates optimized by GA and SCE-UA are 458 619.6 m3/d and 466 119.4 m3/d, respectively). The management model and optimization results provide advice for controlling the land subsidence effectively while reducing the pumping as little as possible. This is of great significance to the sustainable economic development in the study area. Key words pumpage optimization; land subsidence; the Yangtze Delta


Estimation of the leak term and sensitivity analysis at a

LUST groundwater system under data scarcity

JIANFENG WU, JICHUN WU & XIAOBIN ZHUState Key Laboratory of Pollution Control and Resources Reuse, Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, 210093 Nanjing, [email protected]

Abstract With the development and popularization of automobiles in China, the Leaking Underground Storage Tanks (LUSTs) containing gasoline have become potential sources of groundwater contaminant. However, in China information on the occurrence of LUSTs in groundwater is scarce. Based on general enquiries and investigation of 22 LUST sites, a typical one located in Suzhou city was selected to explore the existence of tank leakage and assess its effect on the groundwater quality. Based on the proposition that anaerobic benzene degradation occurs in the aquifer, MODFLOW and MT3DMS, two commonly used groundwater flow and transport simulators, are introduced to simulate the contaminant transport of benzene in groundwater, and determine the leak location and the leak rate at the same time. Considering there are broad categories of modelling uncertainty, the sensitivity analysis is used in this study to address the relative importance of eight model parameters in the established model. This study demonstrates a general framework for identifying the contaminant sources and evaluating the potential impacts of the LUSTs on drinking groundwater sources using numerical simulation models under data scarcity.Key words transport modelling; scarce data; leaking underground storage tank; sensitivity analysis; Suzhou, China


Numerical simulation of potential effects of CO2 leakage on shallow potable aquifers

L. JIANG, Y. L. LI, W. ZHANG & G. B. QIUSchool of Environmental studies, China University of Geosciences, Wuhan 430074, [email protected]

Abstract Increased CO2 release into the atmosphere has led to climate change, known as the greenhouse gas effect. Strategies are being sought to reduce the emissions, including the geological storage of CO2, which is injection of supercritical CO2 into deep geological formations. However, complete characterization of these geological formations is not possible, and the likelihood that some fraction of the injected CO2 will leak into overlying aquifers needs to be considered. If the leaking CO2 enters shallow groundwater aquifers, it could lead to geochemical alterations with detrimental effects on the water quality of these potable aquifers. Identification and assessment of the possible effects is necessary to adequately analyse the risks associated with geological storage of CO2. In order to assess the possible geochemical reactions between water–rock–gas due to the leakage of CO2 from deep formations into upper potable aquifers, a series of reactive geochemical transport simulations based on a 2-D model were performed using TOUGHREACT. Mineralogical composition and water chemistry data from a shallow formation of Jianghan basin in China were used. The objective of the study was to assess the effect of multi-phase processes, geochemical changes and mineral alterations on the water quality of shallow potable aquifers. Because the composition of the strata is not completely precise, a series of sensitivity simulations were performed, using different aquifer mineralogies and assumptions for geochemical system behaviour. The effect of CO2 includes pH changes as well as the solubilization of primary minerals and precipitation of secondary minerals. The simulation results may be useful for preparation of CO2 geological sequestration projects in China.Key words CO2; geological sequestration; numerical simulation; leakage; impact; shallow groundwater



Numerical simulation of impacts of mineralogical compositions on trapping mechanisms and efficiency of carbon dioxide injected into deep saline formations

JUNG-HWI KIHM & JUN-MO KIMSchool of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, Republic of [email protected]

Abstract A series of numerical simulations using a multiphase thermo-hydro-chemical (THC) numerical model is performed to analyse groundwater and carbon dioxide flow and hydrochemical reactive transport due to geological storage of carbon dioxide in a deep saline sandstone aquifer and to evaluate impacts of its mineralogical composition on trapping mechanisms and the efficiency of injected carbon dioxide. The results show that the mineralogy of the sandstone aquifer has significant impacts on the hydro-chemical behaviour of injected carbon dioxide and thus its trapping mechanisms and efficiency. The mineral trapping of injected carbon dioxide takes places as precipitation of carbonate minerals such as calcite, ankerite, dawsonite, siderite and magnesite. Ankerite contributes most to the mineral trapping of injected carbon dioxide. As a result, the precipitation amount of secondary carbonate minerals and the efficiency of mineral trapping increase significantly as the volume fraction of chlorite in the sandstone aquifer increases.Key words carbon dioxide; geological storage; saline formation; mineralogical compositions; hydrodynamic trapping; solubility trapping; mineral trapping


Numerical simulation of two-phase flow in deformable porous media: application to carbon dioxide storage in the subsurface

OLAF KOLDITZ1,2, NORBERT BÖTTCHER2, SEBASTIAN BAUER3, UWE-JENS GÖRKE1, CHAN-HEE PARK1 & WENQING WANG1

1Department of Environmental Informatics, Helmholtz Centre for Environmental Research – UFZ, Permoserstr. 15, D-04318 Leipzig, Germany, [email protected]

2Technische Universität Dresden, Helmholtzstraße 10, D-01069 Dresden, Germany3Christian-Albrechts University of Kiel, Ludewig-Meyn-Straße 10, D-24118 Kiel, Germany

Abstract In this paper, numerical simulation of two-phase flow in deep, deformable geological formations induced by CO2 injection is presented. The underlying conceptual approach is based on balance equations for mass, momentum and energy completed by appropriate constitutive relations for the fluid phases as well as the solid matrix. Within the context of the primary effects under consideration, the fluid motion will be expressed by modified Darcy’s law for two phase flow. To characterize the stress state in the solid matrix, the effective stress principle is applied. Furthermore, interaction of fluid and solid phases is specified by constitutive models for capillary pressure, porosity and permeability as functions of saturation. Based on the conceptual model, a coupled system of nonlinear differential equations is formulated for non-isothermal two-phase flow in a deformable porous matrix (TH2M model). The finite element method is used to solve the multi-field problem numerically. The capabilities of the model and the numerical tools to treat complex processes during CO2 sequestration is checked by benchmarking within a wider scope of a benchmarking scheme, which is also presented and illustrated using two examples: (1) a new benchmark test for H 2M processes, and (2) a 3-D demonstration example to test the stability and computational costs of the H 2 model for real applications. Key words porous media; two-phase flow; deformation; benchmarking; carbon capture storage (CCS)


Validation of reactive transport models for CO2 geological sequestration using TOUGHREACT

TIANFU XUEarth Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA [email protected]

Abstract Geological sequestration of carbon dioxide (CO2) is considered as one way to reduce its release to the atmosphere, and as an essential first step in the control of global warming. Reactive transport modelling can solve many problems and answer questions related to CO2 geological sequestration. In this paper, ways to validate reactive transport models for short-term changes in groundwater chemistry, and long-term fate of injected CO2 are discussed.Key words CO2 geological sequestration; reactive transport modelling; model validation; groundwater quality; mineral trapping


Modelling basin- and plume-scale processes of CO2 storage: a full-scale deployment scenario in the Illinois Basin

QUANLIN ZHOU & JENS T. BIRKHOLZEREarth Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley California 94720, [email protected]

Abstract A basin-scale multiphase flow model was developed to assess the impact of geological carbon sequestration (GCS) in the deep saline Illinois Basin on groundwater resources in northern Illinois, USA. The model covered the Mt Simon Sandstone as storage formation and the overlying Eau Claire aquitard as caprock. A hypothetical scenario, with 20 storage sites in a most suitable core injection area and an annual rate of five million tonnes of CO2 for injection over 50 years at each site, was employed. The integrated modelling of basin-scale groundwater flow and of two-phase CO2–brine flow within CO2 plumes was conducted using the parallel TOUGH2/ECO2N simulator and a 3-D unstructured mesh of 1.25 million gridblocks with local refinement. Simulation results indicate various favourable conditions for safe storage of large volumes of CO2 in Mt Simon, including a deep high-permeability and high-porosity arkosic unit used for CO2 injection, and secondary seals in Mt Simon for significant retardation of upward CO2 migration. The simulated CO2 plume behaviour is supported by observations in natural gas storage fields in the basin, as an analog to GCS. The simulation results also indicate that: (1) significant pressure build-up (~35 bar) in the core injection area is produced, but still ensuring caprock geomechanical integrity, (2) moderate pressure build-up (as high as 1 bar) occurs in northern Illinois and might have an impact on brine intrusion into shallow freshwater aquifers, and (3) no direct impact of brine migration within the updip storage formation in northern Illinois. In comparison, the basin-scale environmental impact of GCS is less significant than that of the long-term intensive groundwater extraction from overlying freshwater aquifers in the metro-Chicago region.Key words CO2 storage; groundwater modelling; environmental impact; geological sequestration


Simulation of land subsidence caused by groundwater exploitation in the Hangzhou-Jiaxing-Huzhou Plain, South China

GUOLIANG CAO1, CHUNMIAO ZHENG1, JIANKANG ZHAO2 & MENGJIE WU2

1 Department of Geological Sciences, University of Alabama, Tuscaloosa, Alabama 35487, USA [email protected]

2 Geo-Environmental Monitoring Station of Zhejiang Province, Hangzhou 310007, China

Abstract The Hangzhou-Jiaxing-Huzhou (Hang-Jia-Hu) Plain, located between the Yangtze and Qiantang rivers, has experienced severe land subsidence since the 1960s and has become one of the regions in China with most acute land subsidence problems. Ample evidence indicates that the land subsidence has resulted from the continuously excessive extraction of groundwater from deep confined aquifers. In this paper, a transient regional groundwater flow and land subsidence model is developed to simulate the evolution of land subsidence. Model calibration is carried out to achieve a reasonable agreement between the observed and simulated amounts of land subsidence in terms of both magnitude and spatial extent. The model results reproduce the centres of land subsidence and the cones of depression for groundwater heads reasonably well. The calibrated model can be used to provide a scientific basis for managing the beneficial use of groundwater resources in the Hang-Jia-Hu Plain while minimizing negative environmental impacts.Key words Hang-Jia-Hu Plain, Zhejiang, China; land subsidence; groundwater extraction; groundwater modelling


The role of aquifer heterogeneity in the anthropogenic uplift of Venice

M. FERRONATO, G. GAMBOLATI & P. TEATINIDepartment of Mathematical Methods and Models for Scientific Applications (DMMMSA), University of Padova, via Trieste 63, I-35121 Padova, [email protected]

Abstract Recent numerical analyses indicate that injecting seawater into a 600–800 m deep brackish aquifer underlying Venice might induce a land uplift of a few tens of centimetres over 10 years, with a significant mitigation of the floods that periodically plague the city. In real porous media, however, the hydraulic conductivity of the injected formation may exhibit a strong heterogeneity which could impact on the uniformity of the expected heave. The present paper investigates the influence of such heterogeneity on the vertical displacements predicted at the ground surface during seawater injection. A Monte Carlo simulation is carried out assuming a log-normal stationary distribution for the hydraulic conductivity with a sensitivity analysis performed on its variance. The results indicate that differential displacements larger than those currently experienced in Venice are never attained, irrespective of the possible, highly uneven aquifer expansion, because of the smoothing effect exerted by the overburden.Key words seawater injection; land uplift; heterogeneity; Monte Carlo analysis; Venice, Italy


Using numerical modelling to study groundwater circulation patterns in the Cretaceous Basin, China

LIHE YIN1, GUANGCAI HOU1, FUSHENG HU2& GUOLIANG CAO2

1Xi’an Center of Geological Survey ,China Geological Survey, No. 438 Youyidong Road, Xi’an, 710054 [email protected]

2 School of Water Resources and Environment, China University of Geosciences, No. 31 Xueyuan Road, 100083 Beijing, China

Abstract The first step of a groundwater flow study for a large-scale basin is to understand the regional patterns of groundwater flow. In this paper, groundwater flow and age were simulated for a cross-section in the Cretaceous Basin. The 240-km long cross-section consists of the main aquifers of the study zone, and is one of the representative hydrogeological sections. The results show that there are three groundwater flow systems. Discussions are presented on the scaling features, groundwater circulation rates and age of local, intermediate and regional flow systems. Circulation patterns of groundwater systems in the Cretaceous Basin are identified Key words groundwater basin; groundwater circulation; flow system; groundwater age


Chlorinated ethene plume migration in groundwater at free-phase petroleum sites

EDWARD MCBEANSchool of Engineering, University of Guelph, Guelph, Ontario N1G 2W1, Canada [email protected]

Abstract Chlorinated ethenes (trichloroethylene, tetrachloroethylene, Cis-DCE and vinyl chloride) are some of the most prevalent organic groundwater contaminants in the world and may evolve into extensive groundwater plumes. However, if areas of free-phase petroleum are present within the boundaries of a chlorinated ethene plume (e.g. at gasoline stations), there may be significant depletion of the chlorinated organics through geochemical interactions between chlorinated ethenes and the petroleum. The velocity of chlorinated ethenes passing through free-phase petroleum may decrease significantly, causing a localized increase in the chlorinated ethene concentrations. The result may be that localized increases in chlorinated ethene concentrations may be orders of magnitude greater within the free-phase petroleum than concentrations immediately upgradient of the free-phase petroleum zone. The result may be that the site is misidentified as a chlorinated ethene source area. Further, there may be significant depletion of the chlorinated ethene groundwater plume on the downgradient side of the free-phase petroleum. The need for calibration of the mathematical model specific to the site exists because responsible evaluation of the fate and transport of chlorinated ethenes must be premised on site-specific processes active within the aquifer.Key words chlorinated ethenes; retardation; free-phase petroloeum; reductive dechlorinating; octanol; LNAPL


Monitoring of aquifer pump tests with Magnetic Resonance Sounding (MRS): a synthetic case study

D. HERCKENRATH1, E. AUKEN2 & P. BAUER-GOTTWEIN1

1Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, DK-2800 Kgs. Lyngby, [email protected]

2Department of Earth Sciences, University of Aarhus, Høegh-Guldbergs Gade 2, DK-8000 Århus C, Denmark

Abstract Magnetic Resonance Sounding (MRS) can provide valuable data to constrain and calibrate groundwater flow and transport models. With this non-invasive geophysical technique, measurements of water content and hydraulic conductivity can be obtained. We developed a hydrogeophyiscal forward method, which calculates the MRS-signal generated by an aquifer pump test. A synthetic MRS-dataset was subsequently used to determine the hydrogeological parameters in an inverse parameter estimation approach. This was done for a virtual pump test with a partially and a fully penetrating well. With the MRS data we were able to retrieve the hydrogeological parameters of the aquifer. However, the differences in MRS signal in time were small compared to the electromagnetic noise. This limits the applicability of the MRS technique for pump tests in which a partially penetrating pumping well is used, as the limited drawdown around the extraction well causes smaller changes in received signal.Key words Magnetic Resonance Sounding (MRS); coupled hydrogeophysical inversion; pump test

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