Download or read book Evaluation of Capture Analysis Bias Associated with Use of Nonlinear Groundwater Flow Models written by Cara Nadler and published by . This book was released on 2016 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water law in the western U.S. typically recognizes surface and groundwater as different sources of water. Because these two systems are often truly connected, groundwater pumping can deplete surface water and is contributing to more frequent litigation by surface water right holders. Surface and groundwater interactions can be quantified through capture analysis, which assesses the decrease in surface water flow rates caused by groundwater pumping. Capture can be described in volumetric terms, or it can be expressed as a fraction of the change in surface water flow rate to the pumping causing the change in flow rate and is often determined through use of groundwater flow models. Capture fractions are a useful means for characterizing the impact of groundwater pumping on streamflow depletion when models behave linearly. However, nonlinear models are often needed to adequately simulate flow processes such as groundwater evapotranspiration and unconfined aquifers. This study quantifies and analyzes the capture bias associated with use of nonlinear groundwater flow models. Generally, bias associated with nonlinear groundwater flow models simulating a connected stream is not affected by selection between the MODFLOW Time-Variant Specified-Head (CHD) and Streamflow-Routing (SFR2) Packages, nor is it significantly affected by variations of streambed hydraulic conductivity of up to two orders of magnitude. Capture fraction bias is significantly altered by disconnected streams, variations in pumping rates, well proximity to capture sources of interest, and by altering the depth at which a well is screened. Understanding the behavior and magnitude of capture fraction bias associated with nonlinear groundwater flow models can help with water management of surface and groundwater interactions.
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 Streamflow depletion by wells written by Paul M. Barlow and published by . This book was released on 2012 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comaprative Evaluation of the Usage of Models for Groundwater Flow and Pollution Studies written by J. F. Bell and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nonlinear Model Reduction for Groundwater Flow and Solute Transport written by zachary p stanko and published by . This book was released on 2019 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Groundwater flow and solute transport models are necessary for understanding the quantity and quality of water in the subsurface. As these models get increasingly complex, their computational runtimes often increase. Reduced models can be developed to approximate the full complex model with reasonable accuracy and shorter runtimes. In this research, proper orthogonal decomposition (POD) is used to identify a lower dimensional subspace that captures most of the information contained in the full model system. Then, because of the nonlinearities present in many flow and transport models, a discrete empirical interpolation method (DEIM) is used to identify an additional lower dimensional subspace that captures the nonlinear dynamics. The reduced modeling framework is implemented within the MODFLOW and MT3DMS software families for groundwater flow and solute transport, respectively. The combined POD-DEIM approach is first applied to an unconfined groundwater flow model where dimensions were reduced by two and three orders of magnitude. The same approach is then applied to a solute transport model simulating nonlinear sorption where dimensions were also reduced by two and three orders of magnitude. The reduced models performed with sufficient accuracy and faster runtimes. The faster runtimes could allow for the reduced models to be embedded into an optimization or uncertainty analysis where thousands to millions of model runs could be required. With the developed POD-DEIM approach, reduced modeling is now viable for any existing MODFLOW or MT3DMS model.
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 760 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 Integrated Groundwater Management written by Anthony J Jakeman and published by Springer. This book was released on 2016-08-05 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this book is to document for the first time the dimensions and requirements of effective integrated groundwater management (IGM). Groundwater management is a formidable challenge, one that remains one of humanity’s foremost priorities. It has become a largely non-renewable resource that is overexploited in many parts of the world. In the 21st century, the issue moves from how to simply obtain the water we need to how we manage it sustainably for future generations, future economies, and future ecosystems. The focus then becomes one of understanding the drivers and current state of the groundwater resource, and restoring equilibrium to at-risk aquifers. Many interrelated dimensions, however, come to bear when trying to manage groundwater effectively. An integrated approach to groundwater necessarily involves many factors beyond the aquifer itself, such as surface water, water use, water quality, and ecohydrology. Moreover, the science by itself can only define the fundamental bounds of what is possible; effective IGM must also engage the wider community of stakeholders to develop and support policy and other socioeconomic tools needed to realize effective IGM. In order to demonstrate IGM, this book covers theory and principles, embracing: 1) an overview of the dimensions and requirements of groundwater management from an international perspective; 2) the scale of groundwater issues internationally and its links with other sectors, principally energy and climate change; 3) groundwater governance with regard to principles, instruments and institutions available for IGM; 4) biophysical constraints and the capacity and role of hydroecological and hydrogeological science including water quality concerns; and 5) necessary tools including models, data infrastructures, decision support systems and the management of uncertainty. Examples of effective, and failed, IGM are given. Throughout, the importance of the socioeconomic context that connects all effective IGM is emphasized. Taken as a whole, this work relates the many facets of effective IGM, from the catchment to global perspective.
Download or read book Guidelines for Delineation of Wellhead Protection Areas written by and published by . This book was released on 1987 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flexible Global Ocean Atmosphere Land System Model written by Tianjun Zhou and published by Springer Science & Business Media. This book was released on 2013-11-19 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coupled climate system models are of central importance for climate studies. A new model known as FGOALS ( the Flexible Global Ocean-Atmosphere-Land System model), has been developed by the Sate Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP, CAS), a first-tier national geophysical laboratory. It serves as a powerful tool, both for deepening our understanding of fundamental mechanisms of the climate system and for making decadal prediction and scenario projections of future climate change. "Flexible Global Ocean-Atmosphere-Land System Model: A Modeling Tool for the Climate Change Research Community” is the first book to offer systematic evaluations of this model’s performance. It is comprehensive in scope, covering both developmental and application-oriented aspects of this climate system model. It also provides an outlook of future development of FGOALS and offers an overview of how to employ the model. It represents a valuable reference work for researchers and professionals working within the related areas of climate variability and change. Prof. Tianjun Zhou, Yongqiang Yu, Yimin Liu and Bin Wang work at LASG, the Institute of Atmospheric Physics, Chinese Academy of Sciences, China.
Download or read book Applied Groundwater Modeling written by Mary P. Anderson and published by Academic Press. This book was released on 2015-08-13 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition is extensively revised throughout with expanded discussion of modeling fundamentals and coverage of advances in model calibration and uncertainty analysis that are revolutionizing the science of groundwater modeling. The text is intended for undergraduate and graduate level courses in applied groundwater modeling and as a comprehensive reference for environmental consultants and scientists/engineers in industry and governmental agencies. - Explains how to formulate a conceptual model of a groundwater system and translate it into a numerical model - Demonstrates how modeling concepts, including boundary conditions, are implemented in two groundwater flow codes-- MODFLOW (for finite differences) and FEFLOW (for finite elements) - Discusses particle tracking methods and codes for flowpath analysis and advective transport of contaminants - Summarizes parameter estimation and uncertainty analysis approaches using the code PEST to illustrate how concepts are implemented - Discusses modeling ethics and preparation of the modeling report - Includes Boxes that amplify and supplement topics covered in the text - Each chapter presents lists of common modeling errors and problem sets that illustrate concepts
Download or read book Review of the New York City Watershed Protection Program written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2020-12-04 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: New York City's municipal water supply system provides about 1 billion gallons of drinking water a day to over 8.5 million people in New York City and about 1 million people living in nearby Westchester, Putnam, Ulster, and Orange counties. The combined water supply system includes 19 reservoirs and three controlled lakes with a total storage capacity of approximately 580 billion gallons. The city's Watershed Protection Program is intended to maintain and enhance the high quality of these surface water sources. Review of the New York City Watershed Protection Program assesses the efficacy and future of New York City's watershed management activities. The report identifies program areas that may require future change or action, including continued efforts to address turbidity and responding to changes in reservoir water quality as a result of climate change.
Download or read book Natural Attenuation for Groundwater Remediation written by Commission on Geosciences, Environment, and Resources and published by National Academies Press. This book was released on 2000-08-31 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past decade, officials responsible for clean-up of contaminated groundwater have increasingly turned to natural attenuation-essentially allowing naturally occurring processes to reduce the toxic potential of contaminants-versus engineered solutions. This saves both money and headaches. To the people in surrounding communities, though, it can appear that clean-up officials are simply walking away from contaminated sites. When is natural attenuation the appropriate approach to a clean-up? This book presents the consensus of a diverse committee, informed by the views of researchers, regulators, and community activists. The committee reviews the likely effectiveness of natural attenuation with different classes of contaminants-and describes how to evaluate the "footprints" of natural attenuation at a site to determine whether natural processes will provide adequate clean-up. Included are recommendations for regulatory change. The committee emphasizes the importance of the public's belief and attitudes toward remediation and provides guidance on involving community stakeholders throughout the clean-up process. The book explores how contamination occurs, explaining concepts and terms, and includes case studies from the Hanford nuclear site, military bases, as well as other sites. It provides historical background and important data on clean-up processes and goes on to offer critical reviews of 14 published protocols for evaluating natural attenuation.
Download or read book Large Scale Inverse Problems and Quantification of Uncertainty written by Lorenz Biegler and published by John Wiley & Sons. This book was released on 2011-06-24 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on computational methods for large-scale statistical inverse problems and provides an introduction to statistical Bayesian and frequentist methodologies. Recent research advances for approximation methods are discussed, along with Kalman filtering methods and optimization-based approaches to solving inverse problems. The aim is to cross-fertilize the perspectives of researchers in the areas of data assimilation, statistics, large-scale optimization, applied and computational mathematics, high performance computing, and cutting-edge applications. The solution to large-scale inverse problems critically depends on methods to reduce computational cost. Recent research approaches tackle this challenge in a variety of different ways. Many of the computational frameworks highlighted in this book build upon state-of-the-art methods for simulation of the forward problem, such as, fast Partial Differential Equation (PDE) solvers, reduced-order models and emulators of the forward problem, stochastic spectral approximations, and ensemble-based approximations, as well as exploiting the machinery for large-scale deterministic optimization through adjoint and other sensitivity analysis methods. Key Features: Brings together the perspectives of researchers in areas of inverse problems and data assimilation. Assesses the current state-of-the-art and identify needs and opportunities for future research. Focuses on the computational methods used to analyze and simulate inverse problems. Written by leading experts of inverse problems and uncertainty quantification. Graduate students and researchers working in statistics, mathematics and engineering will benefit from this book.
Download or read book Physical and Chemical Hydrogeology written by Patrick A. Domenico and published by John Wiley & Sons. This book was released on 1997-10-15 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Completely updated, the second edition of this comprehensive volume not only covers all major areas of hydrogeology, it takes a process-oriented, integrated approach so that readers can gain a complete understanding of the relationship between physical and chemical aspects of this subject. Provides a good balance between theory and application and includes new areas such as contaminant hydrogeology. Includes extensive reference list and suggested readings.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1997 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:
