Download or read book Calibration of MADE 2 Groundwater Flow and Contaminant Transport Models written by and published by . This book was released on 1996 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Public domain computer programs were used to simulate groundwater flow and contaminant migration through a site at the Columbus Air Force Base Mississippi In the MADE-2 (Macrodispersion Experiment a pulse of dissolved contaminants in the saturated zone of an alluvial aquifer was monitored for 15 months. MODFLOW solved for head and seepage velocity for input to the transport code, MT3D. The contaminant transport equation was solved separately from the flow equation since buoyancy effects were assumed to be negligible. Initial simulations of the tritlum plume did not extend far enough from the injection site. An ad hoc assumption of horizontal anisotropy applied to the conductivity field produced good agreement with the observed plumes. Although the simulated plumes were realistic, the horizontally anisotropic conductivity field used to achieve these predictions was not. The principal axes were not aligned with the directions suggested by pump tests or geology, the anisotropy ratio was in excess of any previously observed, and the effective conductivity was above what had been measured at the site. The use of public domain software to model contaminant transport at heterogeneous sites is technically practical; but in the absence of exhaustive field measurements, little confidence can be placed in the predictions.
Download or read book Calibration of a Groundwater Flow and Contaminant Transport Computer Model written by and published by . This book was released on 1989 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: A groundwater flow and contaminant transport model calibration was performed to evaluate the ability of a typical, verified computer code to simulate groundwater tracer migration in the shallow aquifer of the Conasauga Group. Previously, standard practice site data interpretation and groundwater modeling resulted in inaccurate simulations of contaminant transport direction and rate compared with tracer migration behavior. The site's complex geology, the presence of flow in both fractured and weathered zones, and the transient character of flow in the shallow aquifer combined to render inaccurate assumptions of steady-state, homogeneous groundwater flow. The improvement of previous modeling results required iterative phases of conceptual model development, hypothesis testing, site field investigations, and modeling. The activities focused on generating a model grid that was compatible with site hydrogeologic conditions and on establishing boundary conditions based on site data. An annual average water table configuration derived from site data and fixed head boundary conditions was used as input for flow modeling. The contaminant transport model was combined with the data-driven flow model to obtain a preliminary contaminant plume. Calibration of the transport code was achieved by comparison with site tracer migration and concentration data. This study documents the influence of fractures and the transient character of flow and transport in the shallow aquifer. Although compatible with porous medium theory, site data demonstrate that the tracer migration pathway would not be anticipated using conventional porous medium analysis. 126 figs., 22 refs., 5 tabs.
Download or read book Modeling Groundwater Flow and Contaminant Transport written by Jacob Bear and published by Springer Science & Business Media. This book was released on 2010-01-18 with total page 851 pages. Available in PDF, EPUB and Kindle. Book excerpt: In many parts of the world, groundwater resources are under increasing threat from growing demands, wasteful use, and contamination. To face the challenge, good planning and management practices are needed. A key to the management of groundwater is the ability to model the movement of fluids and contaminants in the subsurface. The purpose of this book is to construct conceptual and mathematical models that can provide the information required for making decisions associated with the management of groundwater resources, and the remediation of contaminated aquifers. The basic approach of this book is to accurately describe the underlying physics of groundwater flow and solute transport in heterogeneous porous media, starting at the microscopic level, and to rigorously derive their mathematical representation at the macroscopic levels. The well-posed, macroscopic mathematical models are formulated for saturated, single phase flow, as well as for unsaturated and multiphase flow, and for the transport of single and multiple chemical species. Numerical models are presented and computer codes are reviewed, as tools for solving the models. The problem of seawater intrusion into coastal aquifers is examined and modeled. The issues of uncertainty in model input data and output are addressed. The book concludes with a chapter on the management of groundwater resources. Although one of the main objectives of this book is to construct mathematical models, the amount of mathematics required is kept minimal.
Download or read book Effective Groundwater Model Calibration written by Mary C. Hill and published by John Wiley & Sons. This book was released on 2006-08-25 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods and guidelines for developing and using mathematical models Turn to Effective Groundwater Model Calibration for a set of methods and guidelines that can help produce more accurate and transparent mathematical models. The models can represent groundwater flow and transport and other natural and engineered systems. Use this book and its extensive exercises to learn methods to fully exploit the data on hand, maximize the model's potential, and troubleshoot any problems that arise. Use the methods to perform: Sensitivity analysis to evaluate the information content of data Data assessment to identify (a) existing measurements that dominate model development and predictions and (b) potential measurements likely to improve the reliability of predictions Calibration to develop models that are consistent with the data in an optimal manner Uncertainty evaluation to quantify and communicate errors in simulated results that are often used to make important societal decisions Most of the methods are based on linear and nonlinear regression theory. Fourteen guidelines show the reader how to use the methods advantageously in practical situations. Exercises focus on a groundwater flow system and management problem, enabling readers to apply all the methods presented in the text. The exercises can be completed using the material provided in the book, or as hands-on computer exercises using instructions and files available on the text's accompanying Web site. Throughout the book, the authors stress the need for valid statistical concepts and easily understood presentation methods required to achieve well-tested, transparent models. Most of the examples and all of the exercises focus on simulating groundwater systems; other examples come from surface-water hydrology and geophysics. The methods and guidelines in the text are broadly applicable and can be used by students, researchers, and engineers to simulate many kinds systems.
Download or read book Calibration and Reliability in Groundwater Modelling written by Marc F. P. Bierkens and published by . This book was released on 2006 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several of the papers here deal with decision making under uncertainty.
Download or read book Calibration and Reliability in Groundwater Modelling written by Karel Kovar and published by . This book was released on 2003 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Calibration and Reliability in Groundwater Modelling written by Karel Kovar and published by IAHS Press. This book was released on 1996 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ModelCARE 90 written by Karel Kovar and published by . This book was released on 1990 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific Investigations Report written by Sharon E. Kroening and published by . This book was released on 2004 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Calibration and Reliability in Groundwater Modelling written by Fritz Stauffer and published by . This book was released on 2000 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Contaminant Transport Modeling written by Chunmiao Zheng and published by Wiley. This book was released on 1995-08-07 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applied Contaminant Transport Modeling Theory and Practice Chunmiao Zheng and Gordon D. Bennett The design of remedial systems for groundwater contamination requires a thorough understanding of how various interacting processes — advection, dispersion, and chemical reactions — influence the movement and fate of contaminants. Solute transport simulation provides an ideal vehicle to synthesize these controlling processes, evaluate their interactions, and test the effectiveness of remedial measures. Applied Contaminant Transport Modeling is the first complete resource designed to provide clear coverage of the basic principles of solute transport simulation — including the theory behind the most common numerical techniques for solving transport equations, and step-by-step guidance on the development and use of field-scale models. Written by two experts with extensive practical experience in the field, Applied Contaminant Transport Modeling clearly explains: Factors controlling the transport and fate of solutes in the subsurface —g including advective and dispersive transport and chemical reaction — and the equations governing these processes Development of mathematical models of solute transport regimes and representative analytical solutions to the transport equation Particle tracking as a practical tool for solving many types of field problems Development of Eulerian-Lagrangian methods for solving advection-dispersion-reaction equations Step-by-step development and application of solute transport models — emphasizing problem formulation, model setup, parameter selection, calibration, and sensitivity analysis Sources of uncertainty in transport simulation, and methods of evaluating and managing uncertainty Applied Contaminant Transport Modeling presents detailed case histories illustrating how hydrologists, geologists, chemists, and environmental engineers apply transport models in real-life situations, including landfills, hazardous waste sites, and contaminated aquifers. An optional diskette designed to accompany the text provides software to help the reader explore the concepts and techniques presented in the text and gain hands-on experience in transport simulation. Driven by growing concern over groundwater quality and the rapid dissemination of computer technology, solute transport simulation has become an essential means of evaluating and solving groundwater contamination and remediation problems. Applied Contaminant Transport Modeling provides you with the tools to master this significant field of study.
Download or read book Design and Calibration of RFI Groundwater Flow and Transport Model written by Gary Hecox and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mathematical Models of Contaminant Transport in Groundwater written by Yaron M. Sternberg and published by . This book was released on 1985 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design and Calibration of RFI Groundwater Flow and Solute Transport Model written by Gary R. Hecox and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Comparison of Response Surface Methodology and a One Factor At A Time Approach as Calibration Techniques for the Bioplume II Simulation Model of Contaminant Biodegradation written by and published by . This book was released on 1995 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis compared the Response Surface Methodology (RSM) approach to the one-factor-at-a-time approach for calibrating the Bioplume II finite-difference simulation model of groundwater flow, contaminant transport and biodegradation. The MADE-2 data set of hydrocarbon injection into pristine groundwater at Columbus Air Force Base, Mississippi was used in this research. Because the simulation includes both groundwater flow and contaminant transport, each calibration included both phases. The one-factor-at-a-time approach reduced the root-mean-squared (RMS) error criterion for the flow to 0.921225 feet in a total of 36 runs of Bioplume. The RSM approach reduced the error criterion to 0.918875 feet in a total of 47 runs. The one-factor-at-a-time approach was unable to reduce the RMS error criterion for the transport calibration below an initial value of 67.1831 parts per billion (ppb) benzene after 21 runs which spanned the feasible range of each of the parameters. The RSM approach was able to reduce the response to 67.0327 ppb after 47 runs of Bioplume. The RSM approach allows the modeler to identify parametric regions of improved response in a systematic way that would be extremely difficult to find using the one-factor-at-a-time approach. For this reason it may be very useful for calibration of Bioplume models to be used for research or long term monitoring of a contaminated site, where extra prediction accuracy may be needed. The major limitations of this work were the use of inefficient full factorial designs for the Response Surface Methodology approach and the limited improvement possible on the response surfaces possibly due to the assumption of homogeneous parameter values.
Download or read book Calibration of groundwater flow models for modeling and teaching written by Mickey Charles McBrayer and published by . This book was released on 1999 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Data Requirements for Calibration of a Groundwater Contaminant Transport Model written by Eric W. Strecker and published by . This book was released on 1985 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
