Watersheds: Processes, Assessment and Management

PREFACE xiii

ACKNOWLEDGMENTS xvii

1 INTRODUCTION: COMPREHENSIVE WATERSHED ASSESSMENT AND MANAGEMENT 1

1.0 Introduction 1

1.1 Sustainability 3

1.2 Watershed Assessment and Management 4

1.3 Comprehensive Watershed Management Concepts 4

1.4 Political versus Natural Resource Management 10

1.5 Summary 13

PART A: WATERSHED PROCESSES 17

2 PHYSIOGRAPHY 19

2.0 Introduction 19

2.1 Physiography and Physiographic Provinces 19

2.2 Geology 19

2.3 Soils 30

2.4 Topography 45

2.5 Summary 47

3 CLIMATE, PRECIPITATION, HYDROLOGIC CYCLE 49

3.0 Introduction 49

3.1 Climate Classification 49

3.2 Precipitation 49

3.3 Hydrologic Cycle, Water Balance, and Water Budget 56

3.4 Anthropogenic (Man-made) Changes to the Water Balance 64

3.5 Low Flow 71

3.6 Summary 73

4 HYDROGEOLOGY 76

4.0 Introduction 76

4.1 Groundwater 76

4.2 Flow through Porous Media 82

4.3 Fluid Movement in Unsaturated Media 82

4.4 Fluid Movement in Saturated Media 83

4.5 Flow Through Secondary Openings in Dense Materials 84

4.6 Nitrogen Pollution 84

4.7 Summary 90

5 HYDROGEOMORPHOLOGY (WATERSHED AND STREAM MORPHOLOGY) 92

5.0 Introduction 92

5.1 Hydrogeomorphology 93

5.2 Watershed Classifications 97

5.3 Stream Classifications 104

5.4 Watershed Hydrology 111

5.5 Summary 113

6 LAKES, RESERVOIRS, STREAMS, AND WETLANDS 115

6.0 Introductio 115

6.1 Lentic Water (Ponds, Lakes, Reservoirs) 116

6.2 The Great Dam Debate 123

6.3 Lotic Water (Streams and Rivers) 124

6.4 Physical Properties of Receiving Waters 125

6.5 Wetlands 125

6.6 Summary 133

7 ECOLOGY/HABITAT 135

7.0 Introduction 135

7.1 Ecosystems 135

7.2 Biodiversity 138

7.3 Stressors 139

7.4 Bioindicators 140

7.5 Fisheries 147

7.6 Threatened and Endangered Species 149

7.7 Summary 152

8 WATER QUALITY: NONPOINT SOURCE POLLUTION 155

8.0 Introduction 155

8.1 Water Quality 155

8.2 Chemical Properties of Precipitation 156

8.3 Chemical Properties of Receiving Waters 161

8.4 Point versus Nonpoint Source Pollution 163

8.5 Nonpoint Source (NPS) Pollutants 165

8.6 Buildup and Washoff in Urban Areas 170

8.7 Runoff Pollutant Sources 173

8.8 Summary 173

PART B: WATERSHED ASSESSMENT 183

9 WATERSHED ASSESSMENT: DATA COLLECTION 185

9.0 Introduction 185

9.1 Project Initiation 186

9.2 Establish the Watershed Assessment Team 186

9.3 Involve Citizenry 187

9.4 Select a Consultant 188

9.5 Implement Quality Assurance/Quality Control (QA/QC) 188

9.6 Identify General Problems in the Watershed 188

9.7 Develop Goals and Objectives 189

9.8 Obtain Grant(s) 193

9.9 Hold Public Meetings and Conduct Surveys 194

9.10 Collect Data 196

9.11 Check Local Ordinances 213

9.12 Assimilate Data 214

9.13 Proceed with Analysis: Assessment and Modeling 214

9.14 Write the Plan Report 214

9.15 Summary 216

10 GEOGRAPHIC INFORMATION SYSTEMS 217

10.0 Introduction 217

10.1 Use of GIS for Watershed Assessment 217

10.2 Units, Scale, and Accuracy 218

10.3 Coordinate Systems, Datums, and Projections 219

10.4 GIS Data Types 222

10.5 Metadata 225

10.6 GIS Layers and Data Sources Useful for Watershed Assessment and Analysis 226

10.7 Summary 272

11 PRECIPITATION AND STREAM FLOW DATA 277

11.0 Introduction 277

11.1 Precipitation Measurements 277

11.2 Stream Flow Measurements 288

11.3 Base Flow Separation 307

11.4 Summary 312

12 WATERSHED HYDROLOGY AND MODELING 315

12.0 Introduction 315

12.1 Drainage Area 316

12.2 Time-of-Concentration and Watershed Lag 316

12.3 Runoff 320

12.4 Routing 325

12.5 Modeling Process 327

12.6 Sensitivity Analysis 328

12.7 GIS 331

12.8 Model Calibration Process 331

12.9 Verification 355

12.10 Calibrated Model Runs 357

12.11 Summary 357

13 STREAM AND RIVER MORPHOLOGIC ASSESSMENT 361

13.0 Introduction 361

13.1 Age Classifications 362

13.2 Stream Form (Pattern) 362

13.3 Stream Factors 364

13.4 Stream Classifications 374

13.5 Performing a Fluvial Geomorphological Assessment 379

13.6 Summary 383

14 ECOLOGY: HABITAT CLASSIFICATION AND ASSESSMENT 385

14.0 Introduction 385

14.1 Longitudinal Changes in Stream Ecosystems 385

14.2 Ecosystem Classifications 386

14.3 Ecoregions and Watershed Management 393

14.4 Rapid Bioassessment Protocol (RBP) 394

14.5 Species Diversity Inventory 395

14.6 Aquatic Habitat 395

14.7 Conducting an Aquatic Survey 396

14.8 Aquatic Organism Assessment 400

14.9 Summary 400

15 NONPOINT SOURCE POLLUTION LOAD ASSESSMENT 403

15.0 Introduction 403

15.1 Existing Pollutant Loading Data (NURP) 403

15.2 Field Data Collection and Monitoring 405

15.3 Total Maximum Daily Load (TMDL) 411

15.4 Pollutant Loading Equations and Methods 413

15.5 Revised Universal Soil Loss Equation (RUSLE) 419

15.6 Computer Simulation Models 428

15.7 Summary 430

PART C: WATERSHED MANAGEMENT 433

16 AGENCY ROLES, PROGRAMS, REGULATIONS, AND POLICIES 435

16.0 Introduction 435

16.1 Water Quality Criteria and Standards 436

16.2 Regulations 438

16.3 State, Regional, and Local Regulations 457

16.4 Federal Programs 460

16.5 Greenways and Rivers Conservation Plans 468

16.6 Land Trusts 468

16.7 Summary 469

17 SYSTEMATIC APPROACH TO WATERSHED ASSESSMENT: THE DIGITAL WATERSHED, WATERSHED ANALYSIS, GIS, AND MODELING 471

17.0 Introduction 471

17.1 GIS Applications 471

17.2 Compiling the Digital Watershed 472

17.3 Data Analysis 473

17.4 The GIS Overlaying Procedure 486

17.5 GIS in Hydrologic and Hydraulic Analyses 486

17.6 GIS and Floodplain Management 493

17.7 GIS and Groundwater Management 494

17.8 GIS and Water Quality 495

17.9 Management District Determination 495

17.10 Displaying the Results 497

17.11 Summary 497

18 STORMWATER MANAGEMENT ON A WATERSHED BASIS: REGIONAL STORMWATER MANAGEMENT 499

18.0 Introduction 499

18.1 Urbanization/Land Development 501

18.2 Stormwater Management and Land Development 501

18.3 Watershed-Level Stormwater Runoff Control Management Philosophy 505

18.4 Conventional On-Site Runoff Control versus Watershed Level Runoff Control 505

18.5 Release Rate Percentage Concept 507

18.6 Minimum Reasonable Release Rate Determination 513

18.7 Variable Stormwater Management Districts 514

18.8 Summary 523

19 ON-SITE STORMWATER MANAGEMENT AND CONSERVATION DESIGN 526

19.0 Introduction 526

19.1 Traditional Procedure for Site Design Stormwater Management 527

19.2 Best Management Practices 529

19.3 Five-Phase Approach to Stormwater Management 530

19.4 Nonstructural BMPs and Stormwater Management 550

19.5 The Role of Soils in Low Impact Development 564

19.6 Recommended Procedure for Site Design Stormwater Management: The Low Impact Development Design Planning Process 565

19.7 Advantages and Benefits of LID Design 569

19.8 Future Implementation 569

19.9 Structural BMPs 570

19.10 Summary 583

20 FLOODPLAIN MANAGEMENT AND RIPARIAN BUFFERS 587

20.0 Introduction 587

20.1 Federal Emergency Management Agency’s Flood Insurance Program 589

20.2 Land Development Process in the Floodplain 594

20.3 Room for Improvement 599

20.4 Floodplain and Riparian Buffer Management 602

20.5 Riparian Buffers and Stream Orders 604

20.6 Riparian Buffer Assessment 605

20.7 Riparian Buffer Management 606

20.8 Summary 610

21 STREAM AND LAKE MANAGEMENT 613

21.0 Introduction 613

21.1 Streambank Management Using FGM Techniques 613

21.2 Lake Management 614

21.3 Summary 620

22 GROUNDWATER AND INTEGRATED WATER RESOURCES MANAGEMENT 623

22.0 Introduction 623

22.1 Water Supply Plan 623

22.2 Wellhead Protection Study 625

22.3 Integrated Water Resources Management 632

22.4 Summary 646

23 SUMMARY 648

APPENDIX A SELECTED LIST OF GIS DATA AND RELATED SITES 651

APPENDIX B ACRONYMS 652

GLOSSARY 657

INDEX 690