Aquifer Test Modeling

Description:
In recognition of the trend toward using numerical methods 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.

Table of Contents:
OVERVIEW CONCEPTUAL MODEL DEFINITION Defining Hydrostratigraphic Unit Framework Defining Analytical Conceptual Models Heterogeneous and Vertical Anisotropic Conditions Horizontal Anisotropic Conditions Well Partial Penetration Wellbore Storage Wellbore Skin Unconfined Aquifers Hydrogeologic Boundaries Defining Numerical Conceptual Models Confining Units Unconfined Aquifers Hydrogeologic Boundaries Quantifying Hydraulic Characteristics Defining Well Characteristics Defining Aquifer Test Domain Radius Defining Time Dimensions Groundwater and Surface Water Budgets Flow System External Influences Conceptual Model MATHEMATICAL MODELING EQUATION AND SOFTWARE SELECTION Analytical Mathematical Model Equations Integral and Empirical Mathematical Equations Stehfest Algorithm Pumping Test Mathematical Modeling Equations Stehfest Algorithms Slug Test Mathematical Modeling Equations Horizontal Anistropy Horizontal Heterogeneity Image Well Theory Numerical Mathematical Model Equations Finite-Difference Approximation Method Software Selection EXTERNAL INFLUENCE DATA ADJUSTMENT Confined Aquifer Barometric Efficiency Unconfined Aquifer Barometric Efficiency Barometric Efficiency Calibration Stream Stage Adjustments Tidal Fluctuations Adjustments Dewatering Adjustments DATA ANALYSIS Format Selection Technique Selection Single Plot Type Curve Matching with Interactive Calibration Single Plot Straight-Line Matching with Interactive Calibration Composite Plot Matching with Interactive Calibration Composite Plot Automatic Parameter Estimation Well Function or Drawdown/Head Calculation Calibration Interactive Calibration Automatic Parameter Estimation Time Drawdown Time-Recovery Specific Capacity Step Drawdown Time-Discharge Constant Drawdown Boundary Data MODFLOW Simulation About MODFLOW Versions Pumped Well Drawdown Multilayer Pumped Well Wellbore Storage Delayed Gravity Drainage Grid Design Time Design Transient Confining Unit Leakage Spatial Parameter Difinition Streamlined-Induced Infiltration Dimensionless Time Drawdown EVALUATION SAMPLE DATA FILE SETS REFERENCES APPENDIX A. NOTATION