Engineering Hydrology for Natural Resources Engineers. Edition No. 2

Table of Contents

Acknowledgments, xv

Preface, xvii

About the companion website, xix

1 Natural resources engineering opportunities, 1

1.1 Definitions, 2

1.2 The hydrologic cycle and the water–soil–air–biotic continuum, 3

1.3 Changing land uses due to societal forces, 4

1.4 Natural resources and ecological engineering scope addressed in this text, 5

1.5 Outlook, 11

References, 14

Part One: Quantifying the Hydrologic Cycle

2 Precipitation, 19

2.1 Precipitation mechanisms, types, and measurement, 19

2.2 Precipitation analysis, 23

2.3 Introduction to hydrologic frequency analysis, 25

2.4 Local-scale precipitation analysis, 29

2.5 Calculating storm magnitudes for design purposes, 30

2.5.1 Storm simulation, 30

2.5.2 Probable maximum precipitation, 34

2.6 Pollution transport by precipitation, 34

2.7 The water quality storm, 35

2.8 Climate change and precipitation, 35

2.9 Outlook, 36

References, 37

3 Infiltration, 39

3.1 Infiltration, percolation, and subsurface flow defined, 39

3.2 Factors affecting infiltration of aqueous materials, 40

3.3 Darcy’s law, 41

3.4 Water infiltration and percolation prediction, 45

3.5 Infiltration measurement, 50

3.6 Pollutant transport by subsurface flow, 51

3.7 Outlook, 53

References, 55

4 Evapotranspiration, 57

4.1 Background and factors affecting evapotranspiration, 57

4.2 Evaporation prediction approaches, 58

4.3 Evaporation from water surfaces based solely on aerodynamic effects or mass balance, 58

4.4 Evaporation prediction from the energy-balance–Bowen-ratio method, 60

4.5 Reference evaporation prediction accounting for aerodynamic effects and energy balance – the Penman–Monteith combination equation method, 62

4.6 Empirical and approximate methods for Ep, 70

4.7 Physical simulation and measurements of ET, 74

4.8 Outlook, 77

References, 79

5 Runoff, 81

5.1 Background, 81

5.2 Watershed or catchment delineation, 84

5.3 Runoff volume for a compact watershed, 86

5.4 Peak runoff rate with compact watersheds, 93

5.5 Selecting the design storm, 103

5.6 Frequency analysis of runoff, 111

5.7 Runoff from complex watersheds, 112

5.8 Outlook, 114

References, 118

Part Two: Field- and Farm-Scale Water Quality

6 Water erosion, 123

6.1 Background, 124

6.2 Factors affecting water erosion, 124

6.3 Soil erosion versus sediment yield, 125

6.4 Soil loss tolerance, 126

6.5 Water erosion types, 126

6.6 Erosion mechanics, 128

6.7 Predicting soil detachment and upland erosion, 129

6.8 The weighted RrfCprac factor for average annual erosion computation, 138

6.9 Prediction of sediment yield, 142

6.10 Legal aspects, 145

6.11 Modeling approaches for sediment yield prediction, 145

6.12 Erosion control practices in agriculture, 148

6.13 Erosion and sediment control with construction, 149

6.14 Erosion and nutrient pollution, 152

6.15 Outlook, 152

References, 156

7 Water quality and management at farm/field scales, 159

7.1 Water quality background, 159

7.2 Important concepts and selected pollution measurement techniques, 163

7.3 Scale effects, 165

7.4 Best management practices for nonpoint pollution abatement, 169

7.5 Quantitative removal and renovation of selected pollution constituents, 176

7.6 Modeling pollution fate and transport, 178

7.7 Outlook, 179

References, 181

Part Three: Water management on the field and farm scales

8 Open channel hydraulics – fundamentals, 185

8.1 Hydraulics fundamentals, 185

8.2 Channel design and construction, 194

8.3 Outlook, 208

References, 212

9 Vegetated waterways and bioswales, 215

9.1 Vegetated waterways and diversions, 215

9.2 Bioswales, 222

9.3 Outlook, 225

References, 226

10 On-site erosion management, 229

10.1 Terraces on the farm, 230

10.2 Erosion and sediment control in urban areas, 244

10.3 Outlook, 247

References, 251

11 Hydraulics of water management structures, 253

11.1 Structure types, 254

11.2 Hydraulic concepts, 258

11.3 Stage–discharge relationships of weir inlets and flumes, 259

11.4 Discharge relations of orifices and sluice gate inlet devices, 265

11.5 Flow hydraulics of closed conduits, 265

11.6 Stage–discharge curves for culverts and spillways, 275

11.7 Closed conduit systems for urban storm water collection, 281

11.8 Water measurement structures for irrigation and aquaculture, 282

11.9 Ecologic suitability, 282

11.10 Outlook, 284

References, 287

12 Hydraulics of Impoundments, 289

12.1 Soils fundamentals for embankment construction, 290

12.2 Flood routing through reservoirs and related structures, 297

12.3 General pond design, 303

12.4 Applications, 314

12.5 Outlook, 323

References, 329

13 Shallow Groundwater Management, 331

13.1 Surface drainage, 332

13.2 Subsurface flow fundamentals, 333

13.3 Pipe drainage, 335

13.4 Shallow wells, 347

13.5 Uniform infiltration and drainage to a nearby stream, 353

13.6 Outlook, 354

References, 356

14 Introduction to irrigation, 359

14.1 Irrigation systems overview, 360

14.2 Soil–water–plant relations, 362

14.3 Soil intake rate, 369

14.4 Water quality issues and leaching requirement for crop well-being, 369

14.5 Irrigation efficiency, 372

14.6 Effective rainfall and irrigation scheduling, 374

14.7 Computing ET requirements – peak ET, 376

14.8 Computing ET requirements – seasonal water use, 376

14.9 Irrigation pumping rate for meeting ET requirements, 377

14.10 Water rights and legal underpinnings, 378

14.11 Manual or wheel-move lateral sprinkler system design, 378

14.12 Center pivot system specification, 390

14.13 Linear move irrigation machines, 394

14.14 Design for nontraditional applications, 394

14.15 Microirrigation system design with pressure compensated emitters, 397

14.16 Safety, 401

14.17 Outlook, 401

References, 405

Part Four: Basin-scale Processes

15 Ecological assessment and engineering, 409

15.1 Watershed assessment background, 410

15.2 Watershed assessment methods, 411

15.3 Principles of ecological engineering and ecosystem services, 445

15.4 Outlook, 447

References, 450

Appendices

A Ethics, stakeholder views, case studies, and precision, 457

A catalog of ethical views, 458

Making sense of the ethical catalogue – one person’s view, 461

Resource economics – “social traps”, 462

Case study one – pitcher plant community viability, 463

Case study 2 – a hypothetical case concerning clean water act compliance, 466

Significant digits and presentation precision, 467

References, 468

B Selected Excel® and other software package solutions, 471

Selected symbolic solutions, 472

Determining bottom width and depth in a trapezoidal channel with known slope, side slope, and permissible velocity, 472

Determining depth and side slope in a triangular channel with known slope and permissible velocity, 473

Determining slope and depth in a triangular channel with known flow rate, permissible velocity and side slope (z), 473

References, 474

C Tractive force method for waterway design, 475

Riprap-lined or earthen waterways, 475

Vegetated waterways, 477

References, 479

D Land forming, structure selection, installation, and forces on conduits, 481

Land forming computations, 481

Impoundment and embankment volume calculations, 483

Setting slope stakes for cuts and fills, 486

Techniques for installation of channels and other structures, 486

Layout of circular curves, 487

Small channels or minor topography modifications, 489

Terrace construction and layout, 491

Post-construction stormwater management options, 494

Dry detention pond, 494

Extended wet detention pond, 494

Constructed wetlands, 494

Grass swale, 494

Filter strip and level spreader, 495

Infiltration trench, 495

Oil/grit separator, 495

Source (EPA post-construction) key definitions, 495

Materials specifications for channels and structures, 498

Rural road construction, 498

Buried pipe loading, 499

Trench safety, 502

References, 503

E Selected units conversions, 505

Index, 507

Authors

Ernest W. Tollner Professor of Biological and Agricultural Engineering at the University of Georgia.