Download or read book Bayesian Inverse Problems for Quasi static Poroelasticity with Application to Ground Water Aquifer Characterization from Geodetic Data written by Amal Alghamdi and published by . This book was released on 2020 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Inverse Modeling of Geological Heterogeneity for Goal Oriented Aquifer Characterization written by Heather Marie Savoy and published by . This book was released on 2005 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterizing the spatial heterogeneity of aquifer properties, particularly hydraulic conductivity, is paramount in groundwater modeling when the transport and fate of contaminants need to be predicted. The field of geostatistics has focused on describing this heterogeneity with spatial random functions. The field of stochastic hydrogeology uses these functions to incorporate uncertainty about the subsurface in groundwater modeling predictions. Bayesian inference can update prior knowledge about the spatial patterns of the subsurface (e.g. plausible ranges of values) with a variety of information (e.g. direct measurements of hydraulic conductivity as well as indirect measurements such as water table drawdown at an observation well) in order to yield posterior knowledge. This dissertation focuses on expanding the tools for Bayesian inference of these spatial random functions. First, the development of open-source software tools for guiding users through the Bayesian inference process are described. There is an desktop application that implements the Method of Anchored Distributions and is referred to as MAD#. It is built in a modular fashion such that it can be coupled with any geostatistical software and any numerical modeling software. This modularity allows for a wide variety of spatial random functions and subsurface processes to be incorporated in the Bayesian inference process. There is also a R package, called anchoredDistr, that supplements the MAD# software. While the MAD# software handles the communication between the geostatistical software and the numerical modeling software, the anchoredDistr package provides more flexibility in analyzing the results from MAD#. Since R is an open-source statistical computing language, the anchoredDistr package allows users to take advantage of the plethora of statistical tools in R to calculate the posterior knowledge in the Bayesian process. Although MAD# provides a post-processing module to calculate this posterior knowledge, it does not provide all of the options that the R community can provide for modifications. Second, the expansion of which kinds of data and knowledge can be incorporated into the Bayesian process is explored. Incorporating time series (e.g. the drawdown of a water table from pumping over time) as indirect data in Bayesian inference poses a computational problem referred to as the `curse of dimensionality'. Since each additional measurement in time is correlated with the measurements before and after it, the calculation of probability distributions of these data become multi-dimensional. A synthetic case study incorporating drawdown time series in the Bayesian inference process is explored. A second form of information, conceptual models of geology, is also explored with a synthetic case study. Conceptual models of geology (e.g. a graphical representation of assumed geologic layering) can be described with images. There is a geostatistical technique called Multipoint Statistics that uses images as its input. The synthetic case study provides a proof-of-concept example in which the Bayesian inference process can infer conceptual models of geology using Multipoint statistics. Third, the issue of devising spatial models with realistic geology while constraining the complexity of the model is explored. An aquifer analog is used as the basis for an example. An aquifer analog is a data set with data of hydraulic properties at high spatial resolution, i.e. much higher than expected for ordinary field measurements. The aquifer analog used in this dissertation has ten soil types distributed in three-dimensional space. The objective posed is to predict the early arrival time of a contaminant traveling through the analog. Given this prediction goal, the task is to simplify the analog into a simplified structure without changing the prediction outcome. The purpose of this exercise is to take a goal-oriented approach to defining a parsimonious spatial model for describing this complex aquifer analog such that a geostatistical model can be inferred for this kind of geology in a computationally efficient manner. Ultimately, any uncertainty quantification regarding the spatial heterogeneity of subsurface properties has the goal of improving groundwater modeling prediction efforts. With the addition of freely available software tools, the ability to integrate more forms of information, and methodology for translating complex geological structures into parsimonious spatial models, the characterization of our groundwater resources improves.
Download or read book Parameter Estimation and Uncertainty Quantification in Water Resources Modeling written by Philippe Renard and published by Frontiers Media SA. This book was released on 2020-04-22 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical models of flow and transport processes are heavily employed in the fields of surface, soil, and groundwater hydrology. They are used to interpret field observations, analyze complex and coupled processes, or to support decision making related to large societal issues such as the water-energy nexus or sustainable water management and food production. Parameter estimation and uncertainty quantification are two key features of modern science-based predictions. When applied to water resources, these tasks must cope with many degrees of freedom and large datasets. Both are challenging and require novel theoretical and computational approaches to handle complex models with large number of unknown parameters.
Download or read book Aquifer Test Modeling written by William C. Walton and published by CRC Press. This book was released on 2006-11-15 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recognition of the trend toward using numerical methdos for analyzing aquifer test data, Aquifer Test Modeling delineates the application of numerical Laplace inversion analytical equations and numerical models and demonstrates the use of public domain software. Written by a leading expert with over fifty years of experience, this highly practical text provides a thorough grounding in the terms and methods employed in aquifer test modeling, while also establishing a protocol for organizing and simplifying conceptual model definition and data analysis. Using graphs, tables, and sample datasets to enhance understanding, the author delineates the five major steps involved in the aquifer test modeling process. He discusses the importance of the conceptual model definition as a framework for organizing, simplifying, and idealizing information. The chapters cover the selection of appropriate aquifer test mathematical model equations compatible with previously defined conceptual models and highlight the importance of reviewing the mathematical assumption and the adjustment of data for any departures. They also explain format selection, technique selection, well function or drawdown calculation, and calibration. The book provides five sample data sets to assist the reader in becoming familiar with WTAQ and MODFLOW aquifer test modeling input and output data file contents with confined nonleaky and unconfined aquifer conditions. It includes conceptual models consisting of abbreviated descriptions of aquifer test facilities, aquifer test data, and aquifer parameter values together with selected sample file sets. These are just a few of the features that make the book a valuable tool for estimating the supply and contamination characteristics of aquifers.
Download or read book Aquifer test Design Observation and Data Analysis written by Robert W. Stallman and published by . This book was released on 1971 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Consequences of Spatial Variability in Aquifer Properties and Data Limitations for Groundwater Modelling Practice written by Adrian Peck and published by . This book was released on 1988 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aquifer Testing written by Jonathan D. Istok and published by CRC Press. This book was released on 1991-05-31 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: New! A practical, easy-to-use reference for the design and analysis of groundwater pumping and slug tests Aquifer Testing: Design and Analysis of Pumping and Slug Tests is a complete design and analysis reference emphasizing practical solutions for engineers, scientists, consultants, and students knowledgeable in basic ground water theory. The book discusses such models as steady-state, transient flow with constant discharge, slug injection or withdrawal, and step discharge. This valuable book is an expansion on our best seller Groundwater Pumping Tests: Design and Analysis (Walton 1987). Part I contains general information about pumping tests, including how to design a pumping test, select an appropriate model, correct data, and analyze results. Part II is devoted to aquifer models and features hydrogeologic conditions, flow and geometry assumptions, governing differential equations, initial and boundary conditions, and analytical solutions for different models. BASIC coding for computer programs from which type curves may be developed and drawdown predicted are included in an appendix and on diskettes included in the book.
Download or read book Hessian based Response Surface Approximations for Uncertainty Quantification in Large scale Statistical Inverse Problems with Applications to Groundwater Flow written by Hannah Pearl Flath and published by . This book was released on 2013 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: Subsurface flow phenomena characterize many important societal issues in energy and the environment. A key feature of these problems is that subsurface properties are uncertain, due to the sparsity of direct observations of the subsurface. The Bayesian formulation of this inverse problem provides a systematic framework for inferring uncertainty in the properties given uncertainties in the data, the forward model, and prior knowledge of the properties. We address the problem: given noisy measurements of the head, the pdf describing the noise, prior information in the form of a pdf of the hydraulic conductivity, and a groundwater flow model relating the head to the hydraulic conductivity, find the posterior probability density function (pdf) of the parameters describing the hydraulic conductivity field. Unfortunately, conventional sampling of this pdf to compute statistical moments is intractable for problems governed by large-scale forward models and high-dimensional parameter spaces. We construct a Gaussian process surrogate of the posterior pdf based on Bayesian interpolation between a set of "training" points. We employ a greedy algorithm to find the training points by solving a sequence of optimization problems where each new training point is placed at the maximizer of the error in the approximation. Scalable Newton optimization methods solve this "optimal" training point problem. We tailor the Gaussian process surrogate to the curvature of the underlying posterior pdf according to the Hessian of the log posterior at a subset of training points, made computationally tractable by a low-rank approximation of the data misfit Hessian. A Gaussian mixture approximation of the posterior is extracted from the Gaussian process surrogate, and used as a proposal in a Markov chain Monte Carlo method for sampling both the surrogate as well as the true posterior. The Gaussian process surrogate is used as a first stage approximation in a two-stage delayed acceptance MCMC method. We provide evidence for the viability of the low-rank approximation of the Hessian through numerical experiments on a large scale atmospheric contaminant transport problem and analysis of an infinite dimensional model problem. We provide similar results for our groundwater problem. We then present results from the proposed MCMC algorithms.
Download or read book Aquifer test Design Observation and Data Analysis written by Robert W. Stallman and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aquifer test Design Observation and Data Analysis written by Robert W. Stallman and published by . This book was released on 1971 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Statistical Inverse Modeling and Geostatistical Analysis of the Avra Valley Aquifer written by Peter Maxwell Clifton and published by . This book was released on 1981 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analytical Modelling of Transient Flow to Wells in Complex Aquifer Systems written by Claude M. Sauveplane and published by . This book was released on 1987 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Applicability of Numerical Models to Adequately Characterize Ground Water Flow in Karstic and Other Triple Porosity Aquifers written by GJ. Davies and published by . This book was released on 1996 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical models of ground-water flow have met with limited success when applied to aquifers in soluble rocks, commonly referred to as karstic aquifers. Although modeling of karstic processes is often possible and numerical flow models can sometimes simulate hydraulic heads, ground-water fluxes, and spring discharge, they often fail to correctly predict such fundamental information as flow direction, destination, and velocity. The poor performance of numerical models in karstic aquifers has resulted from: 1) inappropriate emphasis on the local scale when flow paths are often orders of magnitude longer, 2) the large amount of hydrogeologic data required to model such anisotropic, heterogeneous aquifers and the additional data requirements necessary to establish realistic boundary conditions 3) the necessity to develop models which incorporate triple continuum concepts, 4) the difficulty of properly characterizing and modeling transient events in karst aquifers and, 5) the inadequacy of laminar flow equations or Darcy's law to describe the flow in conduits in the aquifer. Most numerical models of ground-water flow in karst aquifers nevertheless continue to employ single-continuum porous-medium models such as MODFLOW and are based on invalid interpolation of inappropriate data collected far too infrequently from points that did not intersect preferential flow paths. Unfortunately, some of these modeling attempts have been substituted for the collection of the additional data that are essential to providing adequate characterization of ground-water flow at sites underlain by karstic aquifers.
Download or read book Characterizing Distributions of Secondary Porosity Features in the Regional Carbonate Aquifer of Ohio Applications to Sustainable Yield written by Heather Marie Thomas and published by . This book was released on 2001 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: The carbonate aquifer of western Ohio contains both primary and secondary porosity, the latter being more important to the flow of ground water. The ground-water flow patterns in this double-porosity carbonate aquifer are controlled, in part, by secondary porosity features. Data for the characterization of the spacing, width, and number of the lateral features were collected from 36 borehole videotapes of municipal, industrial, and monitoring wells completed in the carbonate aquifer. Data for characterization of vertical secondary porosity features were collected at a carbonate aquifer outcrop in a quarry in central Ohio. The borehole videotape data including width, spacing, and number of secondary porosity features were statistically analyzed for the principal hydrostratigraphic units (i.e., the Lockport Dolomite and Salina Group) comprising the carbonate aquifer. The results show that the mean widths of secondary porosity features in the these two units are not statistically different, but the mean spacing and number of secondary porosity features per 100 feet are statistically different. It was also shown that the degrees of spread about the mean width, spacing, and the number of secondary porosity features per 100 feet for the Salina and Lockport are similar. The statistical results were incorporated into interpretive ground-water flow models of the carbonate aquifer using AXIS, an axisymmetric finite-difference numerical modeling program that simulates drawdown in three dimensions in and around a pumping well. The results of this model explain the hydraulic response of a double-porosity medium to a pumping stress. Hypothetical models of single wells were constructed using AXIS and MODFLOW to simulate an aquifer test in Plain City, Ohio. The measured and predicted drawdown data show behavior characteristic of a leaky-confined aquifer where water is derived from elastic storage in the confining layer. The major controls on ground-water flow to the pumping well, such as the secondary porosity features, were examined with additional MODFLOW simulations, and the results show that the lateral enhanced permeability zones are most dominant....
Download or read book Geophysics and Geosequestration written by Thomas L. Davis and published by Cambridge University Press. This book was released on 2019-05-09 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the geophysical techniques and analysis methods for monitoring subsurface carbon dioxide storage for researchers and industry practitioners.
Download or read book The Self Potential Method written by André Revil and published by Cambridge University Press. This book was released on 2013-07-11 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: The self-potential method enables non-intrusive assessment and imaging of disturbances in electrical currents of conductive subsurface materials. It has an increasing number of applications, from mapping fluid flow in the subsurface of the Earth to detecting preferential flow paths in earth dams and embankments. This book provides the first full overview of the fundamental concepts of this method and its applications in the field. It discusses the historical perspective, laboratory investigations undertaken, the inverse problem and seismoelectric coupling, and concludes with the application of the self-potential method to geohazards, water resources and hydrothermal systems. Chapter exercises, online datasets and analytical software enable the reader to put the theory into practice. This book is a key reference for academic researchers and professionals working in the areas of geophysics, environmental science, hydrology and geotechnical engineering. It will also be valuable reading for related graduate courses.
Download or read book Introduction to Geostatistics written by P. K. Kitanidis and published by Cambridge University Press. This book was released on 1997-05-13 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineers and applied geophysicists routinely encounter interpolation and estimation problems when analysing data from field observations. Introduction to Geostatistics presents practical techniques for the estimation of spatial functions from sparse data. The author's unique approach is a synthesis of classic and geostatistical methods with a focus on the most practical linear minimum-variance estimation methods, and includes suggestions on how to test and extend the applicability of such methods. The author includes many useful methods (often not covered in other geostatistics books) such as estimating variogram parameters, evaluating the need for a variable mean, parameter estimation and model testing in complex cases (e.g. anisotropy, variable mean, and multiple variables), and using information from deterministic mathematical models. Well illustrated with exercises and worked examples taken from hydrogeology, Introduction to Geostatistics assumes no background in statistics and is suitable for graduate-level courses in earth sciences, hydrology, and environmental engineering, and also for self-study.
