This document provides details of three research projects. First, a review was conducted on the hydrologic model, ParFlow v3.5.0, to provide information on ParFlow in a format that targets a broader community than a user manual or articles describing specific applications of the model. The history of ParFlow's development, core functionality, model equation discretization and solvers, parallel scaling and performance efficiency, and coupling capabilities of ParFlow with atmospheric, land surface, and subsurface models were discussed. The second project used ParFlow to simulate hydrogeologic conditions of the Walla Walla River Basin (WWRB), southeast Washington and northeast Oregon. Specifically, numerical simulations were performed to test the response of the unconfined aquifer system of the WWRB to supplemental managed aquifer recharge (MAR) scenarios, given a required minimum in-stream flows (ISFs) in the WWR over a 100-year period. The simulations indicated that maintaining minimum ISFs in the WWR and relocating some of the MAR sites downgradient could lead to balanced benefits to all users. The final research project focused on the creation of a three-dimensional groundwater flow model for the Pullman-Moscow Basin, north-central Idaho and southeastern Washington with MODFLOW-2005. The model was used to evaluate alternative water management scenarios to find long-term solutions to aquifer depletion. Model creation and calibration were done using existing hydrogeologic conditions and parameters estimated from previous studies in the basin, and suggestions of future updates to limit model assumptions and uncertainties were provided. Simulation results indicated that pumping less than 25 percent of historic rates (1983-2018) would stabilize/improve groundwater levels in Pullman and Moscow areas.

Arid and semi-arid regions face major challenges in the management of scarce freshwater resources under pressures of population, economic development, climate change, pollution and over-abstraction. Groundwater is commonly the most important water resource in these areas. Groundwater models are widely used globally to understand groundwater systems and to guide decisions on management. However, the hydrology of arid and semi-arid areas is very different from that of humid regions, and there is little guidance on the special challenges of groundwater modelling for these areas. This book brings together the experience of internationally leading experts to fill a gap in the scientific and technical literature. It introduces state-of-the-art methods for modelling groundwater resources, illustrated with a wide-ranging set of illustrative examples from around the world. The book is valuable for researchers, practitioners in developed and developing countries, and graduate students in hydrology, hydrogeology, water resources management, environmental engineering and geography.

Groundwater is a vital resource of water, in some regions of the world the only source of fresh water. Its use for domestic use and agriculture dates back thousands of years. In recent decades the over-exploitation and unabated use of this resource has lead to severe environmental problems such as resource depletion, land subsidence and groundwater

Written by renowned experts in the field, this book assesses the status of groundwater models and defines models and modeling needs in the 21st century. It reviews the state of the art in model development and application in regional groundwater management, unsaturated flow/multiphase flow and transport, island modeling, biological and virus transport, and fracture flow. Both deterministic and stochastic aspects of unsaturated flow and transport are covered. The book also introduces a unique assessment of models as analysis and management tools for groundwater resources. Topics covered include model vs. data uncertainty, accuracy of the dispersion/convection equation, protocols for model testing and validation, post-audit studies, and applying models to karst aquifers.

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.

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

This book provides comprehensive analysis of a number of groundwater issues, ranging from flow to pollution problems. Several scenarios are considered throughout, including flow in leaky, unconfined, and confined geological formations, crossover flow behavior from confined to confined, to semi-confined to unconfined and groundwater pollution in dual media. Several mathematical concepts are employed to include into the mathematical models’ complexities of the geological formation, including classical differential operators, fractional derivatives and integral operators, fractal mapping, randomness, piecewise differential, and integral operators. It suggests several new and modified models to better predict anomalous behaviours of the flow and movement of pollution within complex geological formations. Numerous mathematical techniques are employed to ensure that all suggested models are well-suited, and different techniques including analytical methods and numerical methods are used to derive exact and numerical solutions of different groundwater models. Features: Includes modified numerical and analytical methods for solving new and modified models for groundwater flow and transport Presents new flow and transform models for groundwater transport in complex geological formations Examines fractal and crossover behaviors and their mathematical formulations Mathematical Analysis of Groundwater Flow Models serves as a valuable resource for graduate and PhD students as well as researchers working within the field of groundwater modeling.

CD-ROM contains: Complete FORTRAN source code for MODOFC -- Executable compiled using the Lahey F77L-EM/32 FORTRAN 77 Compiler -- Documentatiion for MODOFC -- Sample problems -- HTML files from the MODOFC Web site.

Groundwater constitutes an important component of many water resource systems, supplying water for domestic use, for industry, and for agriculture. Management of a groundwater system, an aquifer, or a system of aquifers, means making such decisions as to the total quantity of water to be withdrawn annually, the location of wells for pumping and for artificial recharge and their rates, and control conditions at aquifer boundaries. Not less important are decisions related to groundwater qUality. In fact, the quantity and quality problems cannot be separated. In many parts of the world, with the increased withdrawal of ground water, often beyond permissible limits, the quality of groundwater has been continuously deteriorating, causing much concern to both suppliers and users. In recent years, in addition to general groundwater quality aspects, public attention has been focused on groundwater contamination by hazardous industrial wastes, by leachate from landfills, by oil spills, and by agricultural activities such as the use of fertilizers, pesticides, and herbicides, and by radioactive waste in repositories located in deep geological formations, to mention some of the most acute contamination sources. In all these cases, management means making decisions to achieve goals without violating specified constraints. In order to enable the planner, or the decision maker, to compare alternative modes of action and to ensure that the constraints are not violated, a tool is needed that will provide information about the response of the system (the aquifer) to various alternatives.