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.

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 volume covers many of the important advances in the geological sciences from 1963 to 2013. These advances include understanding plate tectonics, exploration of the Moon and Mars, development of new computing and analytical technologies, understanding of the role of microbiology in geologic processes, and many others"--Provided by publisher.