r

Physical and ChemicalHydrogeology

Second Edition

Patrick A. DomenicoDavid R Harris Professor of Geology

Texas A&M University

Franklin W. SchwartzOhio Eminent Scholar in Hydrogeology

Tlte Ohio State University

John Wiley & Sons, Inc.New York Chichester Weinheim Brisbane Toronto Singapore

Contents

2.6

Chapter 1Introduction 11.1 What Is Hydrogeology? 1 2.5

Physical Hydrogeology Before the Early 1940s 2Chemical Hydrogeology Before the Early 1960s 3Post-1960 Hydrogeology 4

1.2 The Relationship Between Hydrogeology andOther Fields of Geology 4

1.3 Hydrologic Cycle 5Components of the Hydrologic Cycle 5Evapotranspiration and PotentialEvapotranspiration 7Infiltration and Recharge 8Base Flow 8Hydrologic Equation 10

Chapter 2 3.1The Origin of Porosity and Permeability 132.1 Porosity and Permeability 13

Porosity and Effective Porosity 13Permeability 15

2.2 Continental Environments 16Weathering 16Erosion, Transportation, and Deposition 17

Fluvial Deposits 17 3-2Eolian Deposits 20Lacustrine Deposits 20Glacial Deposits 20

2.3 The Boundary Between Continental andMarine Environments 20

2.4 Marine Environments 21Lateral and Vertical Succession of Strata 21Ancestral Seas and Their Deposits 22

The Paleozoic Rock Group 23The Mesozoic Rock Group 24The Cenozoic Rock Group 24

Diagenesis in Marine Environments 24Porosity Reduction: Compaction and PressureSolution 24

Chemical Rock-Water Interactions: SecondaryPorosity in Sandstones 26

Uplift, Diagenesis, and Erosion 27The Style of Formations Associated withUplift 27Secondary Porosity Enhancement in CarbonateRocks 29Tectonism and the Formation ofFractures 29Style of Fracturing 30Fluid Pressure and Porosity 31Connectivity 31

Chapter 3Ground-Water Movement 33

Darcy's Experimental Law and FieldExtensions 33The Nature of Darcy's Velocity 34Hydraulic Head: Hubbert's Force Potential 34The Gradient and Ground-Water Flow 36Physical Interpretation of Darcy's ProportionalityConstant 36Units and Dimensions 37Hydraulic Conductivity and Permeability ofGeologic Materials 37Observed Range in Hydraulic ConductivityValues 37Character of Hydraulic ConductivityDistribution 38Anisotropicity and Heterogeneity WithinUnits 39Heterogeneity Among Units and the Classificationof Aquifers 41Creating Hydraulic Conductivity Averages 42Darcy's Law for Anisotropic Material 43Measurement of Hydraulic Conductivity 44

Laboratory Testing 44The Search for Empirical Correlations 44

vii

viH Contents

3.3 Mapping Flow in Geological Systems 45Hydrogeological Cross Sections 46Potentiometric Surface and Water-Table Maps 47Closing Statements 48

3.4 Flow in Fractured Rocks 48Continuum Approach to Fluid Flow 48

Intergranular Porous Rocks 49Fractured Rocks 49

3.5 Flow in the Unsaturated Zone 51Hydraulic and Pressure Heads 51Water Retention Curves 53Darcy's Law for Variably Saturated Flow 54Unsaturated Flow in Fractured Rocks 54

5.2 Surface Features of Ground-Water Flow 91Recharge-Discharge Relations 91Ground Water-Lake Interactions 93Ground Water-Surface Water Interactions 95

5-3 Some Engineering and Geologic Implicationsof Topographic Drive Systems 97Large Reservoir Impoundments 97Excavations: Inflows and Stability 98

The Sea-Level Canal 98Ground-Water Inflows into Excavations 99The Stability of Excavations in Ground-WaterDischarge Areas 99

Landslides and Slope Stability 101

Chapter 4Main Equations of Flow, BoundaryConditions, and Flow Nets 584.1 Organizing the Study of Ground-Water Flow

Equations 584.2 Conservation of Fluid Mass 59

Main Equations of Flow 604.3 The Storage Properties of Porous Media 62

Compressibility of Water and Its Relation toSpecific Storage for Confined Aquifers 63Compressibility of the Rock Matrix: EffectiveStress Concept 64Matrix Compressibility and Its Relation toSpecific Storage of Confined Aquifers 65Equation for Confined Flow in an Aquifer 67Specific Yield of Aquifers 68

4.4 Boundary Conditions and Flow Nets 68Graphic Flow Net Construction 71

4.5 Dimensional Analysis 72

Chapter 5Ground Water in the Basin HydrologicCycle 755.1 Topographic Driving Forces 75

The Early Field Studies 75Conceptual, Graphical, and Mathematical Modelsof Unconfined Flow 76

Effects of Basin Geometry on Ground-WaterFlow 78Effects of Basin Geology on Ground-Water Flow 80

Ground Water in Mountainous Terrain 83Ground Water in Carbonate Terrain 87Ground Water in Coastal Regions 88The Fresh Water-Salt Water Interface in CoastalRegions 89

The Ghyben-Herzberg Relation 89The Shape of the Interface with a SubmergedSeepage Surface 90

Upconing of the Interface Caused by PumpingWells 91

Chapter 6Hydraulic Testing: Models, Methods, andApplications 1036.1 Prototype Geologic Models in Hydraulic

Testing 1036.2 Conventional Hydraulic Test Procedures and

Analysis 105The Theis Nonequilibrium Pumping TestMethod 105

The Curve-Matching Procedure 107Assumptions and Interpretations 107

Modifications of the NonequilibriumEquation 108

Time - Drawdown Method 108Distance-Drawndown Method 109

Steady-State Behavior as a Terminal Case of theTransient Case 109The Hantush-Jacob Leaky Aquifer Method 110Water Table Aquifers 112

6.3 Single-Borehole Tests 114Recovery in a Pumped Well 114The Drill Stem Test 114Slug Injection or Withdrawal Tests 115Response at the Pumped Well: Specific Capacityand Well Efficiency 116

6.4 Partial Penetration, Superposition, andBounded Aquifers 118Partial Penetration 118Principle of Superposition 118Bounded Aquifers 120

6.5 Hydraulic Testing in Fractured or Low-Permeability Rocks 122Single-Borehole Tests 123Multiple-Borehole Tests 123

6.6 Some Applications to HydraulicProblems 124Screen Diameter and Pumping Rates 125Well Yield: The Step-Drawdown Test 125A Problem in Dewatering 125A Problem in Water Supply 127

Contents ix

6.7 Computer-Based Calculations 128Code Demonstration 131Bounded Aquifers Revisited 131

Chapter 7Ground Water as a Resource 1367.1 Development of Ground-Water

Resources 136The Response of Aquifers to Pumping 136Yield Analysis 137

Case Study: The Upper Los Angeles River Area 137Management Strategies 139

Artificial Recharge 139Conjunctive Use 141

7.2 Introduction to Ground-Water FlowSimulation 142Generalized Modeling Approach 142Conceptual Model 142Ground-Water Flow Simulation 143Evaluation of Model Results 144Model Verification 144A Note of Caution 144

7.3 Formulating a Finite-Difference Equation forFlow 145Description of the Finite-Difference Grid 145Derivation of the Finite-Difference Equation 146

7.4 The MODFLOW Family of Codes 147Solving Systems of Finite-DifferenceEquations 148Modular Program Structure 148Illustrative Example 148Operational Issues 152

Time-Step Size 152Drawdowns at "Pumping" Nodes 152Water-Table Conditions 153Boundary Conditions 153

7.5 Case Study in the Application ofMODFLOW 154Model Development 154Data Preparation and Model Calibration 156

Chapter 8Stress, Strain, and Pore Fluids 1598.1 Deformable Porous Media 159

One-Dimensional Consolidation 159Development of the Flow Equation 159The Undrained Response of Water Levels to NaturalLoading Events 160The Drained Response of Water Levels to NaturalLoading Events 163

Land Subsidence as a One-Dimensional DrainedResponse 163

Mathematical Treatment of Land Subsidence 165Three-Dimensional Consolidation 169

Elastic Properties in Deformational Problems 169Flow Equations for Deformable Media 171

8.2 Abnormal Fluid Pressures in ActiveDepositional Environments 172Origin and Distribution 172Mathematical Formulation of the Problem 174Isothermal Basin Loading and TectonicStrain 175

One-Dimensional Basin Loading 176Extensions of the One-Dimensional LoadingModel 177

Thermal Expansion of Fluids 179Fluid Pressures and Rock Fracture 182Phase Transformations 183Subnormal Pressure 184Irreversible Processes 185

8.3 Pore Fluids in Tectonic Processes 185Fluid Pressures and Thrust Faulting 185Seismicity Induced by Fluid Injection 186Seismicity Induced in the Vicinity ofReservoirs 187Seismicity and Pore Fluids at MidcrustalDepths 188The Phreatic Seismograph: Earthquakes andDilatancy Models 188

Chapter 9Heat Transport in Ground-Water Flow 1919.1 Conduction, Convection, and Equations of

Heat Transport 191Fourier's Law 192Convective Transport 193Equations of Energy Transport 194

The Heat Conduction Equation 195The Conductive-Convective Equation 195Dimensionless Groups 196

9.2 Forced Convection 197Temperature Profiles and Ground-WaterVelocity 197Heat Transport in Regional Ground-WaterFlow 199Heat Transport in Active DepositionalEnvironments 203Heat Transport in Mountainous Terrain 205

9.3 Free Convection 207The Onset of Free Convection 207Sloping Layers 208Geological Implications 208

9.4 Energy Resources 209Geothermal Energy 209Energy Storage in Aquifers 209

9.5 Heat Transport and Geologic Repositoriesfor Nuclear Waste Storage 210The Nuclear Waste Program 210The Rock Types 210Thermohydrochemical Effects 212Thermomechanical Effects 213

X Contents

Chapter 10Solute Transport 21510.1 Advection 21510.2 Basic Concepts of Dispersion 216

Diffusion 218Mechanical Dispersion 219

10.3 Character of the DispersionCoefficient 220Studies at the Microscopic Scale 220Dispersivity as a Medium Property 221Studies at Macroscopic and Larger Scales 221

10.4 A Fickian Model of Dispersion 22310.5 Mixing in Fractured Media 22610.6 A Geostatistical Model of Dispersion 228

Mean and Variance 228Autocovariance and AutocorrelationFunctions 229Generation of Correlated Random Fields 230Estimation of Dispersivity 230

10.7 Tracers and Tracer Tests 231Field Tracer Experiments 232

Natural Gradient Test 232Single Well Pulse Test 232Two-Well Tracer Test 233Single Well Injection or Withdrawal with MultipleObservation Wells 233

Estimates from Contaminant Plumes andEnvironmental Tracers 233Massively Instrumented Field Tracer Tests 233

Borden Tracer Experiment 234Validation of the Stochastic Model ofDispersion 235

Chapter 11Principles of Aqueous Geochemistry 23811.1 Introduction to Aqueous Systems 238

Concentration Scales 239Gas and Solid Phases 240

11.2 Structure of Water and the Occurrence ofMass in Water 240

11.3 Equilibrium Versus Kinetic Descriptions ofReactions 240Reaction Rates 241

11.4 Equilibrium Models of Reaction 24lActivity Models 242

11.5 Deviations from Equilibrium 24311.6 Kinetic Reactions 24411.7 Organic Compounds 24511.8 Ground-Water Composition 248

The Routine Water Analysis 248Specialized Analyses 249

11.9 Describing Chemical Data 250Abundance or Relative Abundance 252Abundance and Patterns of Change 253

Chapter 12Chemical Reactions 25512.1 Acid-Base Reactions 255

Natural Weak Acid-Base Systems 256CO2-Water System 256Alkalinity 257

12.2 Solution, Exsolution, Volatilization, andPrecipitation 258Gas Solution and Exsolution 258Solution of Organic Solutes in Water 258Volatilization 259Dissolution and Precipitation of Solids 262Solid Solubility 262

12.3 Complexation Reactions 263Stability of Complexes and SpeciationModeling 263Major Ion Complexation and EquilibriumCalculations 264Enhancing the Mobility of Metals 265Organic Complexation 265

12.4 Reactions on Surfaces 266Sorption Isotherms 266Hydrophobic Sorption of OrganicCompounds 267A'rf-based Approaches for Modeling the Sorptionof Metals 269Multiparameter Equilibrium Models 269

12.5 Oxidation-Reduction Reactions 272Oxidation Numbers, Half-Reactions, ElectronActivity, and Redox Potential 272Kinetics and Dominant Couples 275Control on the Mobility of Metals 276Biotransformation of Organic Compounds 276

12.6 Hydrolysis 27712.7 Isotopic Processes 277

Radioactive Decay 277Isotopic Reactions 278Deuterium and Oxygen-18 279

Chapter 13Colloids and Microorganisms 28213.1 A Conceptual Model of Colloidal

Transport 282Occurrence of Colloidal Material 283Stabilization 283Transport and Filtration 284

13.2 Colloidal Transport in Ground Water 284Sampling and Measuring 284Studies at Cape Cod 285

13.3 Microbiological Systems 285Biofilms 287Sampling and Enumerating MicrobialPopulations 287

Plate Counts 288

Contents XI

Direct Counting Procedures 288Biochemical Techniques 288

Rates of Microbial Reactions 288Microbial Ecology of the Subsurface 290

13.4 Microbial Processes 291Issues in Biodegradation 292Biofilm Kinetics 292

13.5 Biotransformation of CommonContaminants 293Hydrocarbons and Derivatives 293Halogenated Aliphatic Compounds 294Halogenated Aromatic Compounds 294Polychlorinated Biphenyls (PCBs) 295Complex Transformation Pathways 295

Chapter 14The Equations of Mass Transport 29614.1 Mass Transport Equations 296

The Diffusion Equation 296The Advection-Diffusion Equation 297The Advection-Dispersion Equation 297

14.2 Mass Transport with Reaction 298First-Order Kinetic Reactions 298Equilibrium Sorption Reactions 299Heterogeneous Kinetic Reactions 299

14.3 Boundary and Initial Conditions 300

Chapter 15Mass Transport in Natural Ground-WaterSystems 30315.1 Mixing as an Agent for Chemical

Change 303The Mixing of Meteoric and Original FormationWaters 303Diffusion in Deep SedimentaryEnvironments 305

15.2 Chemical Reactions in the UnsaturatedZone 306Gas Dissolution and Redistribution 306Weak Acid-Strong Base Reactions 307Sulfide Oxidation 309Gypsum Precipitation and Dissolution 309Cation Exchange 309Organic Reactions 309

15.3 Chemical Reactions in the SaturatedZone 310Weak Acid-Strong Base Reactions 310Dissolution of Soluble Salts 312Redox Reactions 312Cation Exchange 315

15.4 Case Study of the Milk River Aquifer 31615.5 Age Dating of Ground Water 319

Direct Methods 319Tritium 319

Carbon-14 320Chlorine-36 322

Indirect Methods 322S'"O and SD 322Chlorofluorocarbons 322

Chapter 16Mass Transport in Ground-Water Flow:Geologic Systems 32616.1 Mass Transport in Carbonate Rocks 326

The Approach Toward Chemical Equilibrium inCarbonate Sediments 327The Problem of Undersaturation 329Dolomitization 330

16.2 Economic Mineralization 330Origin of Ore Deposits 331

Roll-Front Uranium Deposits 331Mississippi Valley-Type Lead-Zinc Deposits 332Noncommercial Mineralization: Saline Soils andEvaporites 337

16.3 Migration and Entrapment ofHydrocarbons 337Displacement and Entrapment 337Basin Migration Models 339

16.4 Self-Organization in HydrogeologicSystems 341Patterning Associated with Dissolution 341Patterning Associated with Precipitation andMixed Phenomena 341

Chapter 17Introduction to ContaminantHydrogeology 34417.1 Sources of Ground-Water

Contamination 344Radioactive Contaminants 346Trace Metals 347Nutrients 349Other Inorganic Species 349Organic Contaminants 349

Petroleum Hydrocarbons and Derivatives 349Halogenated Aliphatic Compounds 350Halogenated Aromatic Compounds 350Polychlorinated Biphenyls 350Health Effects 350

Biological Contaminants 35017.2 Solute Plumes as a Manifestation of

Processes 352Fractured and Karst Systems 35"7

Babylon, New York, Case Study 357Alkali Lake, Oregon, Case Study 359

17.3 Design and Quality Assurance Issues inSolute Sampling 36ODesign of Sampling Networks 360Assuring the Quality of Chemical Data 362

XU Contents

17A Sampling Methods 362Conventional Wells or Piezometers 362Multilevel Samplers 363Solid and Fluid Sampling 364Cone Penetrometry 365Other Sampling Methods 367Dissolved Contaminants in the UnsaturatedZone 367

17.5 Indirect Methods for DetectingContamination 367Soil-Gas Characterization 367Geophysical Methods 368

Electrical Methods 369Ground-Penetrating Radar 370Magnetometry 371Seismic Methods 371

Chapter 18Modeling the Transport of DissolvedContaminants 37218.1 Analytical Approaches 372

Advection and Longitudinal Dispersion 372The Retardation Equation 375Radioactive Decay, Biodegradation, andHydrolysis 376Transverse Dispersion 377Models for Multidimensional Transport 378

Continuous Sources 378Numerical Integration of an AnalyticalSolution 380The Instantaneous Point Source Model 380

18.2 Programming the Analytical Solutions forComputers 382

18.3 Numerical Approaches 384A Generalized Modeling Approach 384The Common Solution Techniques 385Adding Chemical Reactions 386

18.4 Case Study in the Application of aNumerical Model 386

Chapter 19Multiphase Fluid Systems 39319.1 Basic Concepts 393

Saturation and Wettability 393Interfacial Tension and Capillary Forces 394Imbibition and Drainage 394Relative Permeability 395Solubility and Effective Solubility 397

19.2 LNAPLs and DNAPLs 398Conceptual Models for the Occurrence ofLNAPLs 399Occurrence of DNAPLs in Ground Water 401Secondary Contamination Due to NAPLs 401Conceptual Models and QuantitativeMethods 403

A Case Study of Gasoline Leakage 404Hyde Park Landfill Case Study 404

19.3 Partitioning 40519.4 Fate of Organics in the Unsaturated

Zone 406Volatilization 406Gas Transport by Diffusion 408Equilibrium Calculations of MassDistributions 409

Mass of VOC in Gas Phase 411Mass of VOC in Aqueous Phase 411Mass of VOC in Sorbed Phase 411Mass of VOC in NAPL Phase 411

19-5 Fate of Organics in the Saturated Zone 411Equilibrium Calculations of MassDistribution 412

19.6 Air-Permeability Testing 41219.7 Recognizing DNAPL Sites 413

Systematic Screening Procedure 414

Chapter 20Remediation: Overview and RemovalOptions 41720.1 Containment 417

Slurry Walls 417Sheet Pile Walls 418Grouting 418Surface Seals and Surface Drainage 418Hydrodynamic Controls 419Stabilization and Solidification 420

20.2 Management Options 42020.3 Overview of Methods for Contaminant

Removal 420Excavation and Ex Situ Treatment 421Pump and Treat 421Interceptor Systems 421Soil-Vapor Extraction 421

20.4 Pump and Treat 422The Problem of Pump and Treat 422Technical Considerations withInjection-Recovery Systems 423Methods for Designing Pump-and-TreatSystems 425

Expanding Pilot-Scale Systems 425Capture Zones 426Analytical Approaches to Defining CaptureZones 426Model-Based Approaches for the Design ofRecovery Systems 429Simulation-Optimization Techniques 429Issues in the Design of Capture Zones 430

20.5 Interceptor Systems for NAPLRecovery 430

20.6 Soil-Vapor Extraction 431Components of an SVE System 432

Contents XiH

When Can SVE Systems Be Used? 433Estimating Removal Rates 434Removal Rate Calculations 435

Field Estimates of Soil Permeability 435Heterogeneity and the Efficiency of SVESystems 436

20.7 Air Sparging 437Airflow and Channeling 437Designing Air-Sparging Systems 438

20.8 Case Studies in Site Remediation 438Oil Spill: Calgary, Alberta 438Gilson Road: Nashua, New Hampshire 439Hyde Park Landfill: Niagara Falls, New York 440Groveland Wells Site, Massachusetts 441

Chapter 21In Situ Destruction and RiskAssessment 44321.1 Intrinsic Bloremediation 44321.2 Bioventing and Bioslurping 445

Applicability of the Technology to ContaminantGroups 446Requirements for Success with BioventingSystems 446In Situ Respiration Testing 447Progress in Solvent Bioremediation 448

21.3 Abiotic Chemical Destruction 449Reactive Barrier Systems 450Funnel-and-Gate Systems 450

21.4 Risk Assessment 450Data Collection and Data Evaluation 451Exposure Assessment 451Toxicity Assessment 453Health-Risk Assessment 454Types of Risk Assessments 455Environmental Risk Assessment 456

21.5 Fernald Case Study 456

Detailed Risk Assessment 457

Answers to Problems 461

Appendix ADerivation of the Flow Equation in aDeforming Medium 463Appendix BAbout the Computer Disk 464Appendix CTable of Atomic Weights 466

References 468

Index 494