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Screening Level Model For Vadose Zone And Ground Water Transport Evaluation
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Book Synopsis Screening Level Model for Vadose Zone and Ground Water Transport Evaluation by : MD. Edlund
Download or read book Screening Level Model for Vadose Zone and Ground Water Transport Evaluation written by MD. Edlund and published by . This book was released on 1997 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper hypothesizes that equations used by numerous screening models to calculate ground water mixing zone depth are conceptually incorrect. The models incorrectly omit contaminated infiltration volumes in calculating the resulting aquifer contaminant mixing and concentrations. As a consequence dilution factor, DF, and site cleanup criteria are also calculated incorrectly. The paper proposes a conservative, yet more reliable, method of estimating dilution factor which takes into account mixing by a receptor point pumping well and downward contaminant displacement due to natural infiltration. Aquifer contaminant concentrations are calculated at the down-gradient edge of the vadose zone source's planar projection on the water table. Processes addressed include advection, degradation, sorption, and volatilization. Using a spreadsheet setup, model equations allow the user to quickly evaluate multiple modeling scenarios with varying source geometry, vadose zone thickness, and soil heterogeneity.
Book Synopsis Parameter Importance of an Analytical Model for Transport in the Vadose Zone by : Tanner Hans Bushnell
Download or read book Parameter Importance of an Analytical Model for Transport in the Vadose Zone written by Tanner Hans Bushnell and published by . This book was released on 2007 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The American Society of Testing and Materials (ASTM) has established a three tier risk-based corrective action (RBCA) program for cleaning up petroleum release sites, which is supported by the Environmental Protection Agency. RBCA programs make the cleanup of spill sites more efficient by requiring additional site information only when a more accurate risk assessment is needed. For spill sites that do not pass the first tier general assessment, a Tier 2 evaluation involving site specific information and screening level models to assess the potential risk must be conducted. Screening level models generally require site specific input parameters. To increase efficiency it would be helpful to know which parameters have large affects on model output and which parameters do not affect the model output significantly. There have been many studies focused on model sensitivity to input parameters. For an input parameter to vary there must be uncertainty about the value. This research proposes a method of including parameter uncertainty with model sensitivity to quantify the importance of a parameter, where the term importance is a combination of parameter uncertainty and sensitivity. Using the method developed in this thesis, an importance assessment was conducted on an analytical model for vadose zone transport. It was found that for sites posing high risk, with large spill volumes and shallow water table depths, the input parameters of water table depth and spill volume were the most important. The input parameters of precipitation and contaminant biodegradation half-life showed high importance in lower risk situations; when the water table was deep. A comparison of sensitivity analysis to importance showed differences in their results. The sensitivity analysis identified those parameters that the model was sensitive to, while the importance assessment identified the parameters that were sensitive and whose range of uncertainty was large enough to affect model output values. This information could be used for resource allocation decisions when acquiring additional site specific information.
Book Synopsis Vadose Zone Processes by : John S. Selker
Download or read book Vadose Zone Processes written by John S. Selker and published by CRC Press. This book was released on 1999-06-28 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vadose Zone Processes provides a unified, up-to-date treatment on the movement of water through unsaturated media. In addition to covering the basic equations governing the flow and fate of water in unsaturated media, the text covers the biogeochemistry of vadose environments and the statistical description of vadose processes. The authors emphasize maintaining an intuitive understanding of how the results are derived and how they are appropriately applied. This comprehensive and important book will be useful not only to those in traditional fields such as civil engineering, geology, crop science, chemical engineering, agricultural engineering, and hydrology but also in the newer environmental engineering fields including containment transport, pollution remediation, and waste disposal.
Book Synopsis Practical Handbook of Soil, Vadose Zone, and Ground-Water Contamination by : J. Russell Boulding
Download or read book Practical Handbook of Soil, Vadose Zone, and Ground-Water Contamination written by J. Russell Boulding and published by CRC Press. This book was released on 2003-09-17 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: A synthesis of years of interdisciplinary research and practice, the second edition of this bestseller continues to serve as a primary resource for information on the assessment, remediation, and control of contamination on and below the ground surface. Practical Handbook of Soil, Vadose Zone, and Ground-Water Contamination: Assessment, Prevention, and Remediation, Second Edition includes important new developments in site characterization and soil and ground water remediation that have appeared since 1995. Presented in an easy-to-read style, this book serves as a comprehensive guide for conducting complex site investigations and identifying methods for effective soil and ground water cleanup. Remediation engineers, ground water and soil scientists, regulatory personnel, researchers, and field investigators can access the latest data and summary tables to illustrate key advantages and disadvantages of various remediation methods.
Book Synopsis Environmental Toxicology and Risk Assessment by : F. James Dwyer
Download or read book Environmental Toxicology and Risk Assessment written by F. James Dwyer and published by ASTM International. This book was released on 1997 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Predicting Fate and Transport of Contaminants in the Vadose Zone Using a Soil Screening Model by :
Download or read book Predicting Fate and Transport of Contaminants in the Vadose Zone Using a Soil Screening Model written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil Screening Levels (SSLs) are threshold concentrations below which there is no concern for the migration of residual soil contaminants to the aquifer above maximum contaminant levels (MCLs). At sites where contaminant concentrations exceed SSLs, further study maybe warranted under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). SSLs are based upon simplified fate and transport assumptions, but the guidance allows the flexibility to develop a detailed modeling approach that accounts for complex site variables such as degradation and thickness of the vadose zone. The distinct advantage of the detailed modeling is that individual sites may calculate a less restrictive, but still protective SSL. A Multi-Layer Vadose Zone Contaminant Migration Model [VZCOMML(C)] was developed at the Savannah River Site to allay the higher costs of detailed modeling and achieve a higher clean-up level. The software model is faster, simpler, and less expensive to us e than other commercially available codes.
Book Synopsis Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory by : National Research Council
Download or read book Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory written by National Research Council and published by National Academies Press. This book was released on 2007-10-18 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world's first nuclear bomb was a developed in 1954 at a site near the town of Los Alamos, New Mexico. Designated as the Los Alamos National Laboratory (LANL) in 1981, the 40-square-mile site is today operated by Log Alamos National Security LLC under contract to the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy (DOE). Like other sites in the nation's nuclear weapons complex, the LANL site harbors a legacy of radioactive waste and environmental contamination. Radioactive materials and chemical contaminants have been detected in some portions of the groundwater beneath the site. Under authority of the U.S. Environmental Protection Agency, the State of New Mexico regulates protection of its water resources through the New Mexico Environment Department (NMED). In 1995 NMED found LANL's groundwater monitoring program to be inadequate. Consequently LANL conducted a detailed workplan to characterize the site's hydrogeology in order to develop an effective monitoring program. The study described in Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report was initially requested by NNSA, which turned to the National Academies for technical advice and recommendations regarding several aspects of LANL's groundwater protection program. The DOE Office of Environmental Management funded the study. The study came approximately at the juncture between completion of LANL's hydrogeologic workplan and initial development of a sitewide monitoring plan.
Download or read book Soil Screening Guidance written by and published by . This book was released on 1996 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Identification and Compilation of Unsaturated/vadose Zone Models by : Paul Van der Heijde
Download or read book Identification and Compilation of Unsaturated/vadose Zone Models written by Paul Van der Heijde and published by . This book was released on 1994 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Practical Handbook of Soil, Vadose Zone, and Ground-Water Contamination by : J. Russell Boulding
Download or read book Practical Handbook of Soil, Vadose Zone, and Ground-Water Contamination written by J. Russell Boulding and published by CRC Press. This book was released on 2016-04-19 with total page 718 pages. Available in PDF, EPUB and Kindle. Book excerpt: A synthesis of years of interdisciplinary research and practice, the second edition of this bestseller continues to serve as a primary resource for information on the assessment, remediation, and control of contamination on and below the ground surface. Practical Handbook of Soil, Vadose Zone, and Ground-Water Contamination: Assessment, Prev
Book Synopsis Assessment and Management of Environmental Risks by : Igor Linkov
Download or read book Assessment and Management of Environmental Risks written by Igor Linkov and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: Managing environmental contamination requires decision makers to weigh eXlstmg risks against the potential effects of implementing environmental policies - considering both the benefits and disruptions that may result from different actions. The NATO Advanced Research Workshop in Lisbon was an important step in the development and application of cost efficient methods of risk assessment especiaIly within the constraints of a budget. The goal of the workshop was to evaluate the potential for risk assessment to serve as a unified and unifying technique in addressing a wide range of environmental problems. Papers presented in this book discuss issues ranging from specific and local studies (specific site, ecosystem, pollutant) to global decision and management frameworks (watersheds, regions, integration of multiple poIlutants and stressors); they develop a range of approaches starting from specific methods to widely applied public policies (Figure 1). The papers show that the use of risk assessment can provide the scientific basis for environmentaIly sound and cost-efficient policies, strategies, and solutions to our environmental chaIlenges. The organization of the Proceedings reflects sessions and discussions during the workshop. The papers in the introductory Chapter summarize the positions of Drs. Glenn Suter (EPA) and Jim Wilson (Resources for the Future) regarding whether the use of often-expensive risk assessments in developing countries can be justified, given evolving regulatory institutions and limited resources.
Book Synopsis Subsurface Fluid Flow (ground-water and Vadose Zone) Modeling by : Joseph D. Ritchey
Download or read book Subsurface Fluid Flow (ground-water and Vadose Zone) Modeling written by Joseph D. Ritchey and published by ASTM International. This book was released on 1996 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Evaluation of Two Sharp Front Models for Vadose Zone Non-aqueous Phase Liquid Transport by :
Download or read book An Experimental Evaluation of Two Sharp Front Models for Vadose Zone Non-aqueous Phase Liquid Transport written by and published by . This book was released on 1994 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ground Water Vulnerability Assessment by : National Research Council
Download or read book Ground Water Vulnerability Assessment written by National Research Council and published by National Academies Press. This book was released on 1993-02-01 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the need to protect ground water from pollution was recognized, researchers have made progress in understanding the vulnerability of ground water to contamination. Yet, there are substantial uncertainties in the vulnerability assessment methods now available. With a wealth of detailed information and practical advice, this volume will help decision-makers derive the most benefit from available assessment techniques. It offers: Three laws of ground water vulnerability. Six case studies of vulnerability assessment. Guidance for selecting vulnerability assessments and using the results. Reviews of the strengths and limitations of assessment methods. Information on available data bases, primarily at the federal level. This book will be indispensable to policymakers and resource managers, environmental professionals, researchers, faculty, and students involved in ground water issues, as well as investigators developing new assessment methods.
Book Synopsis Handbook of Vadose Zone Characterization & Monitoring by : L. Gray Wilson
Download or read book Handbook of Vadose Zone Characterization & Monitoring written by L. Gray Wilson and published by CRC Press. This book was released on 2018-05-02 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is written in a simple, straightforward manner without complicated mathematical derivatives. Compiled by experienced practitioners, this guide covers topics such as basic principles of vadose zone hydrology and prevalent monitoring techniques. Case studies present actual field experiences for the benefit of the reader. The Handbook provides practitioners with the information they need to fully understand the principles, advantages, and limitations of the monitoring techniques that are available. The Handbook of Vadose Zone Characterization & Monitoring expands and consolidates the useful and succint information contained in various ASTM documents, EPA manuals, and other similar texts on the subject, making it an invaluable aid to new practioners and a useful reference for seasoned veterans in the field.
Download or read book GWSCREEN written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non-radioactive substances from surface or buried sources. The code was designed for implementation in the Track I and Track II assessment of Comprehensive Environmental Response, Compensation, and Liability Act sites identified as low probability hazard at the Idaho National Engineering Laboratory. The code calculates 1) the limiting soil concentration such that, after leaching and transport to the aquifer regulatory contaminant levels in groundwater are not exceeded, 2) peak aquifer concentration and associated human health impacts, and 3) aquifer concentrations and associated human health impacts as a function of time and space. The code uses a mass conservation approach to model three processes: contaminant release from a source volume, vertical contaminant transport in the unsaturated zone, and 2D or 3D contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. In Version 2.5, transport in the unsaturated zone is described by a plug flow or dispersive solution model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation in groundwater. Three source models are included; leaching from a surface or buried source, infiltration pond, or user-defined arbitrary release. Dispersion in the aquifer may be described by fixed dispersivity values or three, spatial-variable dispersivity functions. Version 2.5 also includes a Monte Carlo sampling routine for uncertainty/sensitivity analysis and a preprocessor to allow multiple input files and multiple contaminants to be run in a single simulation. GWSCREEN has been validated against other codes using similar algorithms and techniques. The code was originally designed for assessment and screening of the groundwater pathway when field data are limited. It was intended to simulate relatively simple systems and may serve as a predictive tool when the system can be described as such. However, in most cases groundwater systems tend to be substantially more complex than the GWSCREEN conceptual model. Therefore, the primary function of the code has been as a screening and assessment tool.
Book Synopsis Accounting for Time-varying Vadose-zone Water Fluxes Caused by Infiltration Caps Using the MEPAS Transport, Exposure, and Risk Assessment Model by :
Download or read book Accounting for Time-varying Vadose-zone Water Fluxes Caused by Infiltration Caps Using the MEPAS Transport, Exposure, and Risk Assessment Model written by and published by . This book was released on 1993 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Multimedia Environmental Pollutant Assessment System (MEPAS) is an objective, scientific methodology to assess and prioritize hazardous chemical and radionuclide waste disposal sites based on a limited amount of site information. The vadose zone/groundwater transport module (RADCON) of MEPAS was enhanced to simulate scenarios where water-infiltration barriers (caps) have been emplaced over contaminated sites. The computer code was modified to accommodate three periods of constant water flux through the vadose zone (i.e., flux with no cap, fully functioning cap, and partially failed cap). The simulation results from test problems where the cap should have no effect essentially duplicated the simulation results from the same test problems evaluated with the earlier (baseline) version of RADCON (which requires a single constant value of water flux). Therefore, MEPAS assessments of baseline (no-cap) scenarios should be the same as they were when the baseline RADCON code was used as the vadose zone/groundwater transport module. As expected, simulations of preliminary test problems where the cap should have an effect showed that peak concentrations arrived at the receptor later and were reduced in magnitude compared to the no-cap case. Simple criteria were derived to indicate the degree to which results could be affected by violation of the assumptions of the conceptual model. However, even when assumptions are violated, errors on the nonconservative side that could occur as the cap fails should be offset by errors on the conservative side that would have already occurred as the cap was emplaced, resulting in simulations that are conservative overall.
