In cooperation with the Harris–Galveston Subsidence District, Fort Bend Subsidence District, and Lone Star Groundwater Conservation District, the U.S. Geological Survey developed and calibrated the Houston Area Groundwater Model (HAGM), which simulates groundwater flow and land-surface subsidence in the northern part of the Gulf Coast aquifer system in Texas from predevelopment (before 1891) through 2009. Withdrawal of groundwater since development of the aquifer system has resulted in potentiometric surface (hydraulic head, or head) declines in the Gulf Coast aquifer system and land-surface subsidence (primarily in the Houston area) from depressurization and compaction of clay layers interbedded in the aquifer sediments.

The Texas Landscape Project explores conservation and ecology in Texas by presenting a highly visual and deeply researched view of the widespread changes that have affected the state as its population and economy have boomed and as Texans have worked ever harder to safeguard its bountiful but limited natural resources. Covering the entire state, from Pineywoods bottomlands and Panhandle playas to Hill Country springs and Big Bend canyons, the project examines a host of familiar and not so familiar environmental issues. A companion volume to The Texas Legacy Project, this book tracks specific environmental changes that have occurred in Texas using more than 300 color maps, expertly crafted by cartographer Jonathan Ogren, and over 100 photographs that coalesce to fashion a broad portrait of the modern Texas landscape. The rich data, compiled by author David Todd, are presented in clearly written yet marvelously detailed text that gives historical context and contemporary statistics for environmental trends connected to the land, water, air, energy, and built world of the second-largest and second-most populated state in the nation. An engaging read for any environmentalist or conscientious citizen, The Texas Landscape Project provides a true sense of the grand scope of the Lone Star State and the high stakes of protecting it. To learn more about The Meadows Center for Water and the Environment, sponsors of this book's series, please click here.

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