ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02039.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02040.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractIn the Data Quality Objectives (DQO) process, statistical methods are used to determine an optimal sampling and analysis plan. When the DQO decision rule for instituting remedial actions is based on a critical change in water quality, the monitoring program design must ensure that this change can be detected and measured with a specified confidence. Usually the focus is on the change at a single monitoring location and the process is limited to addressing the uncertainty inherent in the analytical methods and the variability at that location. However, new strategies that permit ranking the waste sites and prioritizing remedial activities require the means for assessing overall changes for small regions over time, where both spatial and temporal variability exist and where the uncertainty associated with these variations far exceeds measurement error. Two new methods for assessing these overall changes have been developed and are demonstrated by application to a waste disposal site in Oak Ridge, Tennessee. These methods incorporate historical data where available and allow the user to either test the statistical significance of a linear trend or of an annual change compared to a baseline year for a group of water quality wells.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02043.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAn analysis of the deformation of a homogeneous electrical field caused by a long, thin inclined bed, which is of considerable importance in the exploration of ground water and minerals, is presented using the Hilbert transform. The thickness of the bed and the inclination are expressed as a function of the abscissae of the points of intersection of the horizontal and vertical derivatives of the field. The procedure is illustrated with a theoretical example and substantiated with field examples from the fractured Crystalline Basement Complex in Burkina Faso, Africa, and Pre‐Cambrian limestones of the Cuddappah Basin in Andhra Pradesh, India. The results derived from the analytical method are shown to agree well with the ground trut

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02044.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAn alternative Laplace transform solution for the problem, originally solved by Neuman, of constant discharge from a partially penetrating well in a water‐table aquifer was obtained. The solution differs from existing solutions in that it is simpler in form and can be numerically inverted without the need for time‐consuming numerical integration. The derivation involves the use of the Laplace transform and a finite Fourier cosine series and avoids the Hankel transform used in prior derivations. The solution allows for water in the overlying unsaturated zone to be released either instantaneously in response to a declining water table as assumed by Neuman, or gradually as approximated by Boulton's convolution integral. Numerical evaluation yields results identical with results obtained by previously published methods with the advantage, under most well‐aquifer configurations, of much reduced computation

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02045.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractGround‐water chemistry data from wells are cokriged with ground conductivity measurements to quantitatively describe ground‐water chemical quality at a site. The cokriged estimates are shown to be superior to both simple rescaling of ground conductivity by a linear regression model and to interpolation of ground‐water chemistry data from wells using ordinary kriging. By extending the use of geophysical measurements in this way, significant cost savings in site assessment can be realized and the geophysics will have more data

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02046.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractFor compound mixtures or compounds with two or more differently sorbing isomers which are not analytically distinguished, combined sorption parameters determined in the laboratory are dependent upon the ratio of different compounds or isomers and upon experimental methods and conditions. The purpose of this paper is to mathematically examine the effects of these factors on sorption parameters calculated from batch (shake‐flask) and continuous flow column sorption studies of compound or isomer mixtures. The analysis in this paper helps explain the apparent anomalies between batch and column sorption results in previously published studies of Rhodamine WT (RWT). In batch reactors, the solid: liquid ratio, Rs, has a major effect on batch sorption results. As Rsdecreases, partitioning coefficients determined from batch results approach those determined from column results, which is contrary to the trend that may be anticipated for single component analytes. A single column sorption coefficient or retardation factor for multiple constituents does not accurately describe the transport of the individual compounds. The implications of the effects of experimental methods suggest that sorption parameters determined from batch studies for compound or isomer mixtures (e.g., BTEX, combined xylenes, and others) should be interpreted with care. Significant errors in prediction and description of contaminant transport can result if the presence of multiple compounds or isomers is not recognized or if batch or column data for compound or isomer mixtures are misinterprete

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02047.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractFor a large number of geotechical/ground‐water applications, determining the spatial distribution of the subsoil properties constitutes a major challenge in both design and construction phases. Models that are frequently used for characterization of site properties emphasize the use of probabilistic models that incorporate a number of model parameters to be evaluated. In this paper, neural networks (or neuronets) are used to map the variation of permeability for purposes of identifying boundaries of landfill to be constructed on a real site. The neural network, as a simple technique, was found to be able to logically predict the variation. The sensitivity of the produced permeability maps to both the quality and number of observations was also studied to investigate the accuracy of the proposed mapping methodology. The use of neuronets as a mapping tool can help identify the regions within a site where additional subsoil exploration is warrante

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02048.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractDuring the last several years, the geographic information system (GIS) technology has emerged as an extremely effective tool for analyzing and prioritizing natural resource management alternatives. Because natural resource management problems are spatial in nature, the GIS technology provides a tool for defining the extent of the problem, and facilitates the design and implementation of alternative management strategies. The flexible design of a GIS coupled with the ability to integrate models with spatial data gives resource managers and planners the tools to effectively manage natural resources and to assess the implementation of regulatory policies before they are implemented.This paper describes an interactive modeling system developed within a GIS environment to facilitate rapid appraisal of the susceptibility of ground water to contamination by pesticides. The interactive system combines three widely used screening models with the ARC/INFO GIS software and a graphical user interface. Implemented on a color‐graphic engineering workstation, the interactive modeling system can be used to visualize the spatial distribution of model inputs and outputs. The advantage of this system is that instead of ad‐hoc linkage between GIS software and a simulation model, a fully integrated and interactive system in which the model equations are programmed within the GIS was developed. The impetus for developing the interactive ground‐water modeling system was the relative lack of tools that fully integrate models with GIS and the potential benefits to the resource manager in developing such integrated environmental modeling systems. There is an increasing demand, from the GIS perspective, for tools that perform functions other than organization and display of spatial data. From the ground‐water modeling perspective, several advantages can be derived from fully integrating process‐based models with the data management, analysis, and display capabilities o

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02049.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA method is presented for determining steady‐state capture zones in three dimensions around horizontal drains and vertical wells in homogeneous, anisotropic aquifers in a uniform flow field. Equations are presented for determining drawdown and velocity vector components in three dimensions around drains and wells. Using these equations, a second‐order Runge‐Kutta particle tracking algorithm is applied to trace streamlines in three dimensions. By tracking a large number of particles, it is possible to determine areas where capture occurs and areas where particles escape capture. The resulting 3D capture zones are diagrammed as both 2D (section view) plots and 3D

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1996.tb02050.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY