# Computational Subsurface Hydrology

## Computational Subsurface Hydrology

Computational Subsurface Hydrology: Fluid Flows offers practicing engineers and scientists a theoretical background, numerical methods, and computer codes for the modeling of fluid flows in subsurface media. It will also serve as a text for senior and graduate courses on fluid flows in subsurface media in disciplines such as civil and environmental engineering, agricultural engineering, geosciences, soil sciences, and chemical engineering. Computational Subsurface Hydrology: Fluid Flows presents a systematic derivation of governing equations and boundary conditions of subsurface fluid flow. It discusses a variety of numerical methods, expounds detailed procedures for constructing finite element methods, and describes precise implementation of computer codes as they are applied to subsurface flows. Four computer codes to simulate vertically integrated horizontal flows (FEWA), saturated flows with moving phreatic surfaces in three dimensions (3DFEWA), variably saturated flows in two dimensions (FEMWATER), and variable flows in three dimensions (3DFEMWATER) are attached to this book. These four computer codes are designed for generic applications to both research and practical problems. They could be used to simulate most of the practical, real-world field problems. If you would like a copy of the diskettes containing the four, basic general purpose computer codes referred to in Computational Subsurface Hydrology: Fluid Flows, please email Gour-Tsyh Yeh at the following address : [email protected]

# Computational Subsurface Hydrology

## Computational Subsurface Hydrology

Any numerical subsurface model is comprised of three components: a theoretical basis to translate our understanding phenomena into partial differential equations and boundary conditions, a numerical method to approximate these governing equations and implement the boundary conditions, and a computer implementation to generate a generic code for research as well as for practical applications. Computational Subsurface Hydrology: Reactions, Transport, and Fate is organized around these themes. The fundamental processes occurring in subsurface media are rigorously integrated into governing equations using the Reynolds transport theorem and interactions of these processes with the surrounding media are sophisticatedly cast into various types of boundary conditions using physical reasoning. A variety of numerical methods to deal with reactive chemical transport are covered in Computational Subsurface Hydrology: Reactions, Transport, and Fate with a particular emphasis on the adaptive local grid refinement and peak capture using the Lagrangian-Eulerian approach. The topics on coupled fluid flows and reactive chemical transport are unique contributions of this book. They serve as a reference for research as well as for practical applications with a computer code that can be purchased from the author. Four computer codes to simulate vertically integrated horizontal solute transport (LEMA), contaminant transport in moving phreatic aquifers in three dimensions (3DLEMA), solute transport in variably saturated flows in two dimensions (LEWASTE), and solute transport under variably saturated flows in three dimensions (3DLEWASTE) are covered. These four computer codes are designed for generic applications to both research and practical problems. They could be used to simulate most of the practical, real-world field problems. Reactive chemical transport and its coupling with fluid flows are unique features in this book. Theories, numerical implementations, and example problems of coupled reactive transport and flows in variably saturated media are presented. A generic computer code, HYDROGEOCHEM 3.0, is developed. A total of eight example problems are used to illustrate the application of the computational model. These problems are intended to serve as examples for setting up a variety of simulations that one may encounter in research and field-site applications. Computational Subsurface Hydrology: Reactions, Transport, and Fate offers practicing engineers and scientists a theoretical background, numerical methods, and computer codes for modeling contaminant transport in subsurface media. It also serves as a textbook for senior and graduate course on reactive chemical transport in subsurface media in disciplines such as civil and environmental engineering, agricultural engineering, geosciences, soil sciences, and chemical engineering. Computational Subsurface Hydrology: Reactions, Transport, and Fate presents a systematic derivation of governing equations and boundary conditions of subsurface contaminant transport as well as reaction-based geochemical and biochemical processes. It discusses a variety of numerical methods for moving sharp-front problems, expounds detail procedures of constructing Lagrangian-Eulerian finite element methods, and describes precise implementation of computer codes as they are applied to subsurface contaminant transport and biogeochemical reactions.

# Terrain Analysis and Distributed Modelling in Hydrology

## Terrain Analysis and Distributed Modelling in Hydrology

Leading authorities present the latest advances and anticipate future research directions in this rapidly growing field. New techniques involving simulation visualization software and workstation computer power are considered. Features concepts regarding direct application of newly obtained data and the use of derived indices to assess hydrological, geomorphological and ecological potentials or risk.

# Finite Element Simulation in Surface and Subsurface Hydrology

## Finite Element Simulation in Surface and Subsurface Hydrology

Finite Element Simulation in Surface and Subsurface Hydrology provides an introduction to the finite element method and how the method is applied to problems in surface and subsurface hydrology. The book presents the basic concepts of the numerical methods and the finite element approach; applications to problems on groundwater flow and mass and energy transport; and applications to problems that involve surface water dynamics. Computational methods for the solution of differential equations; classification of partial differential equations; finite difference and weighted residual integral techniques; and The Galerkin finite element method are discussed as well. The text will be of value to engineers, hydrologists, and students in the field of engineering.