Groundwater Hydrology (2^nd Ed.) Engineering, Planning, and Management

Increasing demand for water, higher standards of living, depletion of resources of acceptable quality, and excessive water pollution due to urban, agricultural, and industrial expansions have caused intense environmental, social, economic, and political predicaments. More frequent and severe floods and droughts have changed the resiliency and ability of water infrastructure systems to operate and provide services to the public. These concerns and issues have also changed the way we plan and manage our surface and groundwater resources. Groundwater Hydrology: Engineering, Planning, and Management, Second Edition presents a compilation of the state-of-the-art subjects and techniques in the education and practice of groundwater and describes them in a systematic and integrated fashion useful for undergraduate and graduate students and practitioners. This new edition features updated materials, computer codes, and case studies throughout.

Features:

• Discusses groundwater hydrology, hydraulics, and basic laws of groundwater movement
• Describes environmental water quality issues related to groundwater, aquifer restoration, and remediation techniques, as well as the impacts of climate change \
• Examines the details of groundwater modeling and simulation of conceptual models
• Applies systems analysis techniques in groundwater planning and management
• Delineates the modeling and downscaling of climate change impacts on groundwater under the latest IPCC climate scenarios

Written for students as well as practicing water resource engineers, the book develops a system view of groundwater fundamentals and model-making techniques through the application of science, engineering, planning, and management principles. It discusses the classical issues in groundwater hydrology and hydraulics followed by coverage of water quality issues. It also introduces basic tools and decision-making techniques for future groundwater development activities, taking into account regional sustainability issues. The combined coverage of engineering and planning tools and techniques, as well as specific challenges for restoration and remediation of polluted aquifers sets this book apart.

Contents

Preface .....................................................................................................................xxi

Acknowledgments ..................................................................................................xxv

Authors .................................................................................................................xxvii

Chapter 1 Introduction ..........................................................................................1

1.1 Introduction .................................................................................1

1.2 Water Availability ........................................................................2

1.2.1 Groundwater Availability ................................................4

1.3 Groundwater Systems .................................................................5

1.4 Science and Engineering of Groundwater ...................................6

1.5 Planning and Management of Groundwater ...............................8

1.5.1 Integrated Water Resources Management .....................10

1.5.2 Conflict Issues in Groundwater .....................................10

1.5.3 Economics of Water ......................................................11

1.5.4 Groundwater Sustainability ...........................................13

1.5.5 Supply and Demand Side Management ........................15

1.6 Tools and Techniques ................................................................17

1.7 People’s Perception: Public Awareness .....................................19

1.8 Groundwater Protection: Concerns and Acts ............................20

1.8.1 Clean Water Act.............................................................21

1.8.2 Groundwater Protection ................................................21

1.8.3 USEPA Groundwater Rule ............................................22

1.8.4 California’s Sustainable Groundwater

Management Act ...........................................................23

1.9 Overall Organization of This Book ...........................................24

Problems .............................................................................................25

References ..........................................................................................25

Chapter 2 Groundwater Properties ......................................................................29

2.1 Introduction ...............................................................................29

2.2 Vertical Distribution of Subsurface Water .................................31

2.3 Aquifers, Aquitards, and Aquicludes ........................................33

2.4 Types of Aquifers ......................................................................33

2.4.1 Unconfined Aquifer .......................................................33

2.4.2 Confined Aquifers .........................................................34

2.4.3 Aquitard (Leaky) Aquifer ..............................................34

2.5 Groundwater Balance ................................................................35

2.5.1 Water Balance in Confined Aquifers .............................36

2.5.2 Water Balance in Unconfined Aquifers .........................37

2.5.3 Water Balance in Unsaturated Zone ..............................37

2.6 Compressibility and Effective Stress .......................................38

2.6.1 Compressibility of Water ...........................................38

2.6.2 Effective Stress ..........................................................38

2.6.3 Compressibility of a Porous Medium ........................40

2.6.4 Effective Stress in the Unsaturated Zone ..................42

2.7 Aquifer Compressibility ..........................................................42

2.8 Aquifer Characteristics ............................................................43

2.8.1 Porosity and Void Ratio .............................................44

2.8.2 Specific Yield in Unconfined Aquifers ......................46

2.8.3 Specific Retention......................................................47

2.8.4 Storage Coefficient and Specific Storage ..................48

2.8.5 Safe Yield of Aquifers ...............................................52

2.9 Storage in the Unsaturated Zone .............................................52

2.10 Water-Level Fluctuations .........................................................55

2.11 Groundwater in Karst ..............................................................55

2.11.1 Karst Aquifer .............................................................55

2.11.2 Types of Karst............................................................56

2.11.3 Fluctuation of Karst Aquifer ......................................56

2.11.4 Recharge of Karst Aquifer .........................................57

2.11.5 Groundwater Tracing in Karst ...................................58

2.11.6 Water Resources Problems in Karst ..........................58

Problems .............................................................................................59

References ..........................................................................................61

Chapter 3 Groundwater Hydrology .....................................................................63

3.1 Introduction .............................................................................63

3.2 Groundwater Movement ..........................................................63

3.2.1 Darcy’s Law ...............................................................63

3.2.1.1 Validity of Darcy’s Law..............................68

3.2.2 Hydraulic Head ..........................................................68

3.2.3 Hydraulic Conductivity .............................................69

3.2.3.1 Hydraulic Conductivity in Saturated

Media ..........................................................69

3.2.3.2 Hydraulic Conductivity in Unsaturated

Media ..........................................................70

3.2.3.3 Laboratory Measurement of Hydraulic

Conductivity ...............................................72

3.2.3.4 Field Measurement of Hydraulic

Conductivity ...............................................74

3.3 Homogeneous and Isotropic Systems ......................................75

3.3.1 Hydraulic Conductivity in Multilayer Structures ......76

3.4 Transmissivity .........................................................................80

3.5 Dupuit–Forchheimer Theory of Free-Surface Flow ................81

3.6 Groundwater Flow in Unsaturated Zone .................................83

3.7 Flownets .....................................................................................88

3.7.1 Isotropic and Homogeneous Media .............................88

3.7.2 Heterogeneous Media ..................................................92

3.7.3 Anisotropic Media .......................................................93

3.8 Statistical Methods in Groundwater Hydrology ........................95

3.8.1 Normal Distribution .....................................................95

3.8.2 Lognormal Distribution ...............................................97

3.8.3 t-Distribution ................................................................98

3.8.4 Chi-Square (χ2) Distribution ......................................100

3.8.5 Errors .........................................................................100

3.8.5.1 Sampling Error ..........................................100

3.8.5.2 Standard Errors .........................................100

3.8.6 Estimating Quantiles (Percentiles) ............................101

3.8.7 Probability/Frequency/Recurrence Interval ...............102

3.9 Time Series Analysis ...............................................................103

3.9.1 Nonstationary Hydrologic Variables ..........................103

3.9.2 Hydrologic Time Series Modeling .............................104

3.9.3 Data Preparation ........................................................105

3.9.4 Parameter Estimation .................................................108

3.9.4.1 Method of Moments .................................108

3.9.4.2 Method of L-Moments ..............................109

3.9.4.3 Method of Least Squares ..........................110

3.9.4.4 Method of Maximum Likelihood .............111

3.9.5 Goodness of Fit Tests .................................................113

3.9.5.1 Chi-Square Goodness of Fit Test ..............113

3.9.5.2 Tests of Normality ....................................115

3.9.6 Akaike’s Information Criterion ..................................117

3.9.7 Autoregressive Modeling ...........................................117

3.9.8 Moving Average Process ............................................121

3.9.9 Autoregressive Moving Average Modeling ...............122

3.9.9.1 Generation and Forecasting Using

ARMA Models .........................................122

3.9.10 Autoregressive Integrated Moving Average

Modeling ....................................................................123

3.9.10.1 Time Series Forecasting Using

ARIMA Models ........................................124

Problems ...........................................................................................130

Appendix ..........................................................................................132

References ........................................................................................135

Chapter 4 Hydraulics of Groundwater ..............................................................139

4.1 Introduction ............................................................................. 139

4.2 Continuity Equation .................................................................139

4.3 Equation of Motion in Groundwater .......................................142

4.3.1 Groundwater Flow Equation ......................................144

4.4 Wells ........................................................................................153

4.4.1 Steady Flow into a Well ...............................................155

4.4.1.1 Confined Flow ...............................................155

4.4.1.2 Unconfined Flow ...........................................158

4.4.2 Unsteady State in a Confined Aquifer .........................161

4.4.2.1 Aquifer Test Application ...............................165

4.4.2.2 Theis Method of Solution .............................166

4.4.2.3 Cooper–Jacob Method of Solution ...............168

4.4.2.4 Variable Pumping Test ..................................172

4.4.3 Unsteady State for Unconfined Aquifer ......................175

4.5 Multiple-well Systems .............................................................181

4.6 Effective Conditions on Time-Drawdown Data ......................182

4.6.1 Recharge Boundary .....................................................182

4.6.2 Impermeable Boundary ...............................................184

4.6.3 Partially Penetrating Wells...........................................186

4.7 Design of Wells ........................................................................188

4.8 Well Construction ....................................................................191

4.8.1 Cable-Tool Drilling ......................................................191

4.8.2 Rotary Drilling Method ...............................................191

4.8.2.1 Well Development ........................................192

Problems ...........................................................................................193

References ........................................................................................197

Chapter 5 Groundwater Quality ........................................................................199

5.1 Introduction .............................................................................199

5.2 Groundwater Constituents and Contaminants .........................199

5.2.1 Inorganic Contaminants ...............................................199

5.2.2 Organic Contaminants .................................................200

5.2.3 Dissolved Gasses .........................................................200

5.2.4 Particles .......................................................................202

5.3 Water Quality Standards ..........................................................203

5.4 Groundwater Solubility ...........................................................209

5.5 Disequilibrium and Saturation Index .......................................212

5.6 Sources of Groundwater Contamination .................................214

5.6.1 Disposal of Solid Wastes .............................................214

5.6.2 Underground Petroleum Tank Leakage .......................214

5.6.3 Disposal of Liquid Wastes ...........................................215

5.6.4 Sewage Disposal on Land ............................................215

5.6.5 Agricultural Activities .................................................216

5.6.6 Other Sources of Contamination .................................216

5.7 Mass Transport of Dissolved Contaminants ............................217

5.7.1 Diffusion ......................................................................218

5.7.2 Advection.....................................................................220

5.7.3 Mechanical Dispersion ................................................221

5.7.4 Hydrodynamic Dispersion ...........................................224

5.7.5 Derivation of the Advection–Dispersion Equation ......225

5.7.6 Solute Transport Equation ...........................................233

5.7.7 Capture-Zone Curves ...................................................234

5.8 Modeling Contaminant Release ..............................................240

5.8.1 Modeling Instantaneous Release of Contaminants ......240

5.8.1.1 Fourier Analysis in Solute Transport ............240

5.8.1.2 Point Spill Model ..........................................241

5.8.1.3 Vertically Mixed Spill Model .......................241

5.8.1.4 Vertical Mixing Region ................................242

5.8.2 Modeling Continuous Release of Contaminants .........244

5.8.2.1 Development of Contaminant Plume

Models ..........................................................244

5.8.2.2 Simple Plume Model ....................................244

5.8.2.3 Point-Source Plume Model ...........................245

5.8.2.4 Gaussian-Source Plume Model .....................245

Problems ...........................................................................................248

References ........................................................................................250

Chapter 6 Groundwater Modeling ....................................................................251

6.1 Introduction .............................................................................251

6.2 Process of Modeling ................................................................251

6.3 Mathematical Modeling ...........................................................252

6.3.1 Analytical Modeling ....................................................253

6.3.2 Numerical Modeling ....................................................254

6.4 Finite-Difference Method ........................................................254

6.4.1 Forward Difference Equation ......................................257

6.4.2 Backward Difference Equation....................................261

6.4.3 Alternating Direction Implicit Method ........................262

6.4.4 Crank–Nicolson Difference Equation .........................281

6.5 Finite Element Method ............................................................284

6.5.1 Discretize the Problem Domain ...................................284

6.5.2 Derive the Approximating Equations ..........................290

6.5.3 Transient Saturated Flow Equation .............................303

6.5.4 Solute Transport Equation ...........................................311

6.6 Finite Volume Method .............................................................319

6.6.1 Steady-State One-Dimensional Flow Equation ...........319

6.6.2 Unsteady-State, One-Dimensional Flow Equation ......323

6.6.3 Two-Dimensional Flow Equation ................................324

6.6.4 Orthogonals Coordinate System ..................................333

6.7 Simulation of Groundwater Flow Using the Discrete

Kernel Approach ......................................................................336

6.8 Saturated-Unsaturated Transport (SUTRA) Code ...................346

6.9 MODFLOW .............................................................................347

Problems ...........................................................................................364

References ........................................................................................366

Chapter 7 Groundwater Planning and Management .........................................369

7.1 Introduction .............................................................................369

7.2 Data Collection ........................................................................370

7.3 Simulation Techniques ............................................................371

7.3.1 Model Calibration .......................................................372

7.3.2 Model Verification .......................................................372

7.3.3 Model Predictions .......................................................373

7.3.3.1 Artificial Neural Networks ...........................374

7.3.3.2 Fuzzy Sets and Parameter Imprecision ........389

7.3.3.3 System Dynamics .........................................395

7.3.3.4 Agent-Based Modeling .................................405

7.4 Optimization Models for Groundwater Management .............409

7.4.1 Optimization Model for Groundwater Operation ........410

7.4.2 Optimization Model for Capacity Expansion ..............413

7.4.3 Optimization Model for Water Allocation ...................417

7.4.4 Optimization Model for Conjunctive Water Use .........420

7.4.5 Optimal Groundwater Quality Management Model ...421

7.4.6 Optimization Model for Parameters of

Groundwater Model ....................................................422

7.5 Optimization Techniques .........................................................423

7.5.1 Single-Criterion Optimization .....................................424

7.5.2 Multi-criteria Optimization .........................................426

7.5.2.1 Sequential Optimization ...............................427

7.5.2.2 The ε-Constraint Method ..............................427

7.5.2.3 The Weighting Method .................................428

7.5.2.4 Interactive Fuzzy Approach ..........................430

7.5.3 Special Methods for Groundwater Optimization ........432

7.5.3.1 Dynamic Programming ................................432

7.5.3.2 Genetic Algorithm ........................................434

7.5.3.3 Simulation Annealing ...................................438

7.6 Conflict Resolution ..................................................................440

7.6.1 Stakeholder Involvement .............................................446

7.6.1.1 Effective Meeting Facilitation ......................447

7.6.1.2 Conflict Handling .........................................447

7.6.1.3 Quantifying Meeting Outcomes ...................448

7.6.2 Application of Game Theory in Multi-objective

Groundwater Management ..........................................449

7.6.2.1 Non-cooperative Stability Definitions ..........452

7.7 Groundwater Systems Economics ...........................................452

7.7.1 Economic Analysis of Multiple Alternatives ...............457

7.7.2 Economic Evaluation of Projects Using

Benefit–Cost Ratio Method .........................................459

7.8 Case Studies ............................................................................460

7.8.1 Case 1: Development of a System Dynamics

Model for Water Transfer ............................................460

7.8.1.1 Area Characteristics .....................................461

7.8.1.2 Conflict Resolution Model for Land

Resources Allocation in Each Zone..............461

7.8.1.3 Results of the Conflict Resolution Model ....463

7.8.1.4 Optimal Groundwater Withdrawal in

Each Zone .....................................................464

7.8.1.5 Sizing Channel Capacity ..............................464

7.8.1.6 Conclusion—Making Technologies Work ...465

7.8.2 Case 2: Conflict Resolution in Water Pollution

Control for an Aquifer .................................................466

7.8.2.1 Water Resources Characteristics

in the Study Area ..........................................466

7.8.2.2 Conflict Resolution Model ...........................468

7.8.2.3 Results and Discussion .................................471

7.8.3 Case 3: An Agent-Based Modeling Application

in Groundwater ............................................................472

7.8.3.1 Case Study Characteristics ...........................472

7.8.3.2 Model Characteristics ...................................473

7.8.3.3 Model Calibration and Verification ..............475

7.8.3.4 Results of Agent-Based Modeling ................475

7.8.4 Case 4: Development of a Noncooperative Game

in Groundwater Management ......................................476

7.8.4.1 Area Characteristics .....................................476

7.8.4.2 Simulation-Multi-objective Optimization

Model ...........................................................477

Problems ...........................................................................................482

References ........................................................................................486

Chapter 8 Surface Water and Groundwater Interaction ....................................491

8.1 Introduction .............................................................................491

8.2 Interaction between Surface and Groundwater .......................491

8.2.1 Infiltration ....................................................................492

8.2.2 Concepts of Interaction between Surface Water and

Groundwater ................................................................492

8.2.3 Bank Storage and Baseflow Recession .......................495

8.2.3.1 Master-Depletion Curve Method ..................496

8.2.3.2 Seasonal Recession Method (Meyboom

Method) ........................................................497

8.2.3.3 Constant-Discharge Baseflow Separation ....498

8.2.3.4 Constant-Slope Baseflow Separation ...........498

8.2.3.5 Concave-Baseflow Separation ......................499

8.2.4 Groundwater and Lakes ...............................................500

8.3 Conjunctive Use of Surface and Groundwater ........................502

8.3.1 Advantages of Conjunctive Use ..................................503

8.3.2 Impediments of Conjunctive Use ................................504

8.3.3 Case Study 1: Conjunctive Use of Surface

and Groundwater in Lakhaoti Canal Uttar

Pradesh, India ..............................................................504

8.3.4 Surface and Groundwater Conjunctive Use

Modeling .....................................................................507

8.3.5 Multi-objective Conjunctive Use Optimization ..........515

8.3.5.1 Groundwater Resource Sustainability

Limits ...........................................................516

8.3.6 Case Study 2: Application of Genetic Algorithms

and Artificial Neural Networks in Conjunctive Use

of Surface and Groundwater Resources ......................517

8.3.6.1 Simulation Model .........................................517

8.3.6.2 Optimization Model Framework ..................521

8.3.6.3 Results and Discussion .................................523

8.3.7 Case Study 3: Water Allocation from the

Aquifer-River System Using a Conflict

Resolution Model ........................................................524

8.3.7.1 Optimization Model Framework ..................528

8.3.7.2 Results and Discussion .................................530

8.3.8 Case Study 4: Conjunctive Use and Crop Pattern

Management ................................................................532

8.3.8.1 Optimization Model Structure ......................534

8.3.8.2 Results and Discussion .................................537

8.4 Operation of Groundwater Resources in Semiarid Region .....538

Problems ...........................................................................................540

References ........................................................................................541

Chapter 9 Aquifer Restoration and Monitoring ................................................543

9.1 Introduction .............................................................................543

9.2 Partitioning Process .................................................................544

9.3 Retardation ..............................................................................546

9.4 Natural Losses of Contaminants..............................................547

9.4.1 Volatilization ...............................................................548

9.4.2 Biological Degradation ...............................................548

9.4.3 Plant Uptake ................................................................549

9.5 Groundwater Pollution Control ...............................................550

9.5.1 Institutional Tools ........................................................550

9.5.1.1 Regional Groundwater Management ...........550

9.5.1.2 Land Zoning .................................................550

9.5.1.3 Effluent Charges/Credits ..............................550

9.5.1.4 Guidelines ....................................................551

9.5.1.5 Aquifer Standards and Criteria .....................551

9.5.2 Source Control Strategies ............................................551

9.5.3 Stabilization/Solidification Strategies .........................552

9.5.4 Well Systems ...............................................................554

9.5.5 Interceptor Systems .....................................................554

9.5.6 Surface Water Control, Capping, and Liners ...............555

9.5.7 Sheet Piling .................................................................556

9.5.8 Grouting ......................................................................557

9.5.9 Slurry Walls .................................................................557

9.6 Treatment of Groundwater ......................................................559

9.6.1 Air Sparging ................................................................559

9.6.2 Carbon Adsorption ......................................................560

9.6.3 Adding Chemicals and In Situ Chemical Oxidation ...561

9.6.4 Thermal Technologies .................................................562

9.6.5 Bioremediation Techniques .........................................563

9.6.6 Dissolved Phase (Plume) Remediation .......................564

9.6.6.1 Pump and Treat ............................................564

9.6.6.2 Permeable Reactive Barriers ........................564

9.7 Aquifer Restoration—Overdraft Issues ...................................566

9.7.1 Case Study: The National Restoration and

Remediation of Groundwater Resources in Iran .........567

9.7.1.1 General Purpose ...........................................567

9.7.1.2 Projects .........................................................567

9.7.1.3 Operational Program (Action Plans) ............568

9.7.1.4 Time Table ....................................................569

9.8 Monitoring Subsurface Water ..................................................569

9.8.1 Vadose-Zone Monitoring.............................................570

9.8.2 Groundwater Monitoring .............................................571

9.8.3 Water Quality Variable Selection ................................572

9.8.4 Geostatistical Tools for Water Quality-Monitoring

Networks .....................................................................573

9.8.4.1 Kriging .........................................................574

9.8.5 Location of Water Quality Monitoring Stations ..........577

9.8.5.1 Definition and Discretization of the

Model Domain .............................................578

9.8.5.2 Calculation of Weights for Candidate

Monitoring Sites ...........................................579

9.8.5.3 Optimal Configuration of a Monitoring

Well Network ...............................................580

9.8.5.4 Kriging Method in Designing an Optimal

Monitoring Well Network ............................581

9.8.5.5 Genetic Algorithms in Designing an

Optimal Monitoring Well Network ..............582

9.8.6 Sampling Frequency ....................................................584

9.8.6.1 Methods of Selecting Sampling Frequencies ....584

9.8.6.2 Single Station and Single Water Quality

Variable ........................................................585

9.8.6.3 Single Station and Multiple Water

Quality Variables ....................................586

9.8.6.4 Multiple Stations and a Single Water

Quality Variable ......................................587

9.8.6.5 Multiple Stations and Multiple Water

Quality Variables ....................................588

9.8.7 Entropy Theory in a Water Quality-Monitoring

Network ...................................................................588

9.8.7.1 Entropy Theory .......................................589

9.9 Managed Aquifer Recharge ...................................................591

9.9.1 Principal Consideration ...........................................591

9.9.1.1 Sources of Recharge Water and Its

Quality Considerations ...........................593

9.9.1.2 Hydrogeological Settings and

Controls on Recharge .............................594

9.9.1.3 MAR Methods ........................................595

9.9.2 MAR in Support of Groundwater Sustainability .....600

9.9.2.1 MAR in Urban Settings ..........................600

9.9.2.2 MAR in Agricultural Settings .................602

9.9.2.3 MAR in Coastal Areas ............................606

9.9.3 The United Nations MAR Portal .............................607

9.10 Summary ...............................................................................607

Problems ...........................................................................................607

References ........................................................................................609

Chapter 10 Groundwater Risk and Disaster Management ..................................615

10.1 Introduction ...........................................................................615

10.2 Groundwater Risk Assessment ..............................................616

10.2.1 Elements of Risk Assessment ..................................616

10.2.2 Assessment of Dose-Response ................................618

10.2.3 Risk Assessment Methods and Tools .......................619

10.2.3.1 Potency Factor for Cancer-Causing

Substances ..............................................620

10.2.4 Environmental Risk Analysis ..................................624

10.3 Groundwater Risk Management ............................................625

10.3.1 Groundwater Risk Mitigation ..................................626

10.4 Groundwater Disaster ............................................................627

10.4.1 Requirements for Institutional and Technical

Capacities ................................................................627

10.4.2 Prevention and Mitigation of Natural and

Man-Induced Disasters ............................................628

10.4.3 Disaster Management Phases ..................................629

10.5 Disaster Indices .....................................................................630

10.5.1 Reliability ................................................................630

10.5.2 Resiliency ................................................................636

10.5.3 Vulnerability ............................................................636

10.6 Groundwater Vulnerability ....................................................637

10.6.1 Drought ....................................................................638

10.6.1.1 Drought Indicators ..................................641

10.6.1.2 Drought Triggers .....................................641

10.6.1.3 Drought Management Strategy Plan .......643

10.6.1.4 Drought Vulnerability Maps ...................643

10.6.1.5 Drought Early Warning Systems ............644

10.6.1.6 Case Study ..............................................644

10.6.1.7 Qanats .....................................................645

10.6.2 Flood ........................................................................647

10.6.2.1 Maps of Groundwater Flood Hazard ......648

10.6.3 Land Subsidence ......................................................650

10.6.3.1 Subsidence Calculation ...........................651

10.6.3.2 Monitoring Land Subsidence ..................652

10.6.3.3 Reducing Future Subsidence ..................652

10.6.3.4 Examples of Subsidence .........................653

10.6.4 Widespread Contamination .....................................653

10.6.4.1 Vulnerability Assessment in

Groundwater Pollution ............................657

10.6.4.2 DRASTIC Method ..................................659

10.6.5 Case Study: Development of Vulnerability Maps

for a Drought ...........................................................664

10.6.5.1 Summary .................................................668

Problems ...........................................................................................669

References ........................................................................................671

Chapter 11 Climate Change Impacts on Groundwater .......................................675

11.1 Introduction ...........................................................................675

11.2 Climate Change .....................................................................676

11.3 Climate Change Impacts on Hydrological Cycle ..................677

11.3.1 Floods and Droughts ................................................678

11.3.2 Agricultural Droughts ..............................................679

11.3.3 Water Use ................................................................679

11.3.4 Water Quality ...........................................................680

11.3.5 Habitat .....................................................................680

11.3.6 Hydroelectric Power ................................................680

11.3.7 Snowpack .................................................................681

11.3.8 River Flow ...............................................................681

11.4 General Climate Change Impacts on Groundwater ...............681

11.4.1 Hydrological Components Affecting the

Groundwater ............................................................683

11.4.1.1 Temperature and Evaporation .................683

11.4.1.2 Precipitation ............................................683

11.4.1.3 Soil Moisture ..........................................685

11.4.2 Direct Impacts of Climate Change on

Groundwater ............................................................686

11.4.2.1 Groundwater Recharge ...........................687

11.4.2.2 Recharge Estimation Methods ................688

11.4.2.3 Aquifers Recharging ...............................689

11.4.2.4 Hydraulic Conductivity ...........................689

11.4.3 Indirect Impacts of Climate Change on

Groundwater ............................................................690

11.4.3.1 Sea-Level Rise ........................................690

11.4.3.2 Saltwater Intrusion in Coastal

Aquifers ..................................................691

11.4.3.3 Storm Surge and Saltwater Intrusion ......693

11.4.3.4 Ghyben–Herzberg Relation between

Freshwater and Saline Waters .................694

11.4.3.5 Island Freshwater Lens ...........................695

11.4.3.6 Land Use and Land Cover ......................698

11.5 Groundwater Quantity and Quality Concerns .......................698

11.5.1 Depletion of Groundwater Table .............................698

11.5.2 Deterioration of Groundwater Quality ....................699

11.5.2.1 Increasing Groundwater Contamination ....699

11.5.2.2 Salinization of Groundwater by

Sea-Level Rise ........................................699

11.6 Adaptation to Climate Change ..............................................700

11.6.1 Artificial Recharge ...................................................701

11.6.2 Modification of Groundwater Extraction Pattern ....701

11.6.3 Injection Barrier .......................................................702

11.6.4 Subsurface Barrier ...................................................702

11.6.5 Tidal Regulators .......................................................702

11.7 IPCC Assessment Report .......................................................702

11.8 Climate Change Simulation ...................................................704

11.8.1 Spatial Variability ....................................................705

11.8.1.1 Recent Communities’ Scenarios

Development ...........................................705

11.8.1.2 Downscaling ...........................................707

11.8.1.3 Regional Models .....................................708

11.8.2 Statistical Downscaling ...........................................709

11.9 Downscaling Models .............................................................712

11.9.1 Statistical Downscaling Model ................................712

11.9.2 LARS-WG Model ...................................................715

11.10 New Insights—Risks and Vulnerabilities ............................724

11.11 Climate Change Impacts on Water Availability in an

Aquifer .................................................................................725

11.12 Conclusion ...........................................................................732

Problems ...........................................................................................732

References ........................................................................................734

Index ...................................................................................................................... 739