Water

About the Author xi

Preface xiii

Acknowledgements xv

Introduction 1

References 5

1 Our History with Water: What Can Be Learned from Past Water-based Communities 7

Mesopotamia 8

Qanats 11

Egypt 12

Ancient Greece 14

Classical Greece and Roman 16

Roman Empire 16

Ancient American Civilisations 20

Some of the Changes from the Thirteenth to Nineteenth Centuries 23

What Can We Learn from These Ancient Approaches to Water Management? 25

References 27

2 Water Movement in Time and Space 31

Atmospheric Water, Clouds and Precipitation 36

Spatial Variations in Precipitation and Run-off 37

Groundwater 42

Water Movement Through Evaporation and Precipitation 44

Glaciers, Ice Fields and Snow Melt 45

Groundwater 47

Rivers, Lakes and Reservoirs 50

Rivers 50

Lakes 52

Lakes and Reservoirs 57

References 59

3 Human Needs and Water Demands. How Much Water Do We Need? 63

Our Basic Water Needs 64

Our Right to Water 65

Basic Water Requirements 69

Factors Driving Water Demand 70

Water Withdrawals and Use in the United States 71

Sectoral Water Demand and Consumption 77

Agriculture 77

Energy 80

Industry 82

Humans and Human Settlements 82

Water Abstractions and Use in Europe 86

References 88

4 Water Resources 93

The Driving Forces Behind the Global Climate 99

Evaporation and Precipitation 102

Glacier and Snowmelt 103

Groundwater 105

Surface Freshwater Resources 111

Lakes and Reservoirs 115

Sand Dams 117

Rainwater and Fog Harvesting 119

Rainwater Harvesting for Domestic Use 124

Rainwater Quality 124

Floods and Droughts 125

Floods 125

Droughts 129

References 131

5 Water Scarcity 135

What Is Water Scarcity? 136

Our Right to Water 137

Water Availability, Demand and Allocation 138

Industry Demands 141

Municipal Water Demands 141

Water Demands for Agriculture 141

Estimating Freshwater Availability and Scarcity Using Indices 142

Falkenmark Index 144

Water Poverty Index (WPI) 145

Access 146

Water Quality and Availability 146

Water for Agriculture and Other Productive Activities 146

Capacity to Manage Water 147

Environmental Aspects 147

Questions of Spatial Scale 147

The Social Water Stress Index 152

Water Resources Vulnerability Index (WRVI) 153

Water Resources Availability and Food (Especially Cereals Imports) 154

Index of Local Relative Water Use and Reuse 154

Watershed Sustainability Index and Water Resources Vulnerability Index 156

Environmental Sustainability Index (ESI) 157

References 164

6 Water Quality: Some Management and Use Issues 169

Added Nutrients and Eutrophication 174

Phosphorus 181

Controlling Nutrient Inputs 182

Nitrogen 183

Eutrophication and Harmful Algal Blooms 191

Mitigation of Nitrogen and Phosphorus Inputs to the Environment 193

Artificial Mixing 198

Dredging 200

Algicides 200

Examples of European and United States Regulations and Regulatory Authorities Responsible for Water 202

Local Water Agencies 209

Municipal Water Departments 209

Water and Sewer Districts 209

Flood-control Districts 209

Mutual Ditch and Irrigation Companies 209

Regional Water Agencies 210

Conservancy Districts 210

Natural Resource Districts 210

Groundwater Management Districts as in Kansas 210

State Water Agencies 210

Multistate Water Agencies 211

Missouri River Basin Association 211

The Ogallala Aquifer 212

References 215

7 Drinking Water Treatment 221

Aims for Provision of Drinking Water and Sanitation 222

Drinking Water Treatment 233

Pre-treatment 241

Screens 241

Filtration 247

Sand Pre-filters 248

Activated Carbon 251

Ion Exchange 252

Membrane Filters 253

Microfiltration 256

Ultrafiltration 257

Nanofiltration 257

Reverse Osmosis 258

Membrane Integrity 258

Backwashing 258

Coagulation and Flocculation 259

Dissolved Air Flotation (DAF) 261

Slow Sand Filtration 266

Chemical and Microbiological Actions 269

Natural Organic Matter 270

Arsenic removal 274

Cleaning a Slow Sand Filter 276

Disinfection 277

Ultraviolet Radiation 277

Ozone 279

Chlorine 281

Disinfection By-products of Chlorination 283

Sodium Hypochlorite and Calcium Hypochlorite Disinfectants 283

General Considerations for Disinfection 284

References 285

8 Wastewater Treatment 291

Preliminary Treatment: Screening and Grit Removal 296

Storm Water 298

Primary Sedimentation 298

Activated Sludge (AS) Process 299

Diffused Air 299

Surface Aeration 301

Vertical Shaft Rotors 301

Horizontal Shaft Aerators 302

Mixed Liquor Suspended Solids 304

Biological Filtration 304

Possible Problems with Filters 308

Humus Tanks (Secondary Sedimentation Tanks) 309

Rotating Biological Contactors (RBC) 310

Sludge Treatment and Disposal 311

Waste Stabilisation Pond Treatment 312

Anaerobic Ponds 314

Facultative Ponds 314

Maturation Ponds 315

Water Storage and Treatment Reservoirs 315

Constructed Wetlands (CWs) 316

Vertical Flow Wetlands 318

Septic Tanks 321

Disposal of Sewage Sludge 322

Incineration 322

Disposal to Land 323

Disposal to Agriculture 324

References 327

9 Climate Change and Its Implications for Freshwater in the Future 331

Impacts on Human Settlements 338

Precipitation 340

Streamflow 342

Groundwater 344

Changes in Water Quality 344

Droughts 345

Climate Change and Freshwater and Terrestrial Ecosystems 348

Inland Fisheries 350

Effects on Agriculture and Food 352

References 354

10 Sustainability: The Way Ahead and Can We Achieve It - A Summary 361

Virtual Water and Water Footprint 365

Reducing Water Demand 367

Domestic Water Saving Strategies 370

References 373

Glossary 377

Index 383