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Low Impact Development and Sustainable Stormwater Management

E-Book

$71.99

Low Impact Development and Sustainable Stormwater Management

Thomas H. Cahill

ISBN: 978-1-118-20244-9 June 2012 312 Pages

Description

Sustainable Stormwater Management introduces engineers and designers to ideas and methods for managing stormwater in a more ecologically sustainable fashion. It provides detailed information on the design process, engineering details and calculations, and construction concerns. Concepts are illustrated with real-world examples, complete with photographs. This guide integrates the perspectives of landscape architects, planners, and scientists for a multi-disciplinary approach. This is an enlightening reference for professionals working in stormwater management, from engineers and designers to developers to regulators, and a great text for college courses.

Prologue: Habitat, Sustainability, and Stormwater Management xi

Acknowledgments xiii

1 Rainwater as the Resource 1

1.1 The Water Balance as a Guide for Sustainable Design 1

1.2 The Water Balance by Region 7

1.3 Arid Environments: The Southern California Model 11

The Energy Demand for Water in Southern California 13

1.4 The Altered Water Balance and Hydrologic Impacts 16

Imperviousness 16

Increased Volume of Runoff 20

1.5 The Impacts of Development on the Hydrologic Cycle 24

Reduced Groundwater Recharge 24

Reduced Stream Base Flow 25

Altered Stream Channel Morphology 26

Water Supply Impacts 26

1.6 The Historic Approach: Detention System Design 27

1.7 Stormwater Volume Methodologies 30

2 Stormwater Hydrology and Quality 33

2.1 Overland Flow: The Beginning of Runoff 33

2.2 Regional Hydrology 35

Wetlands 36

First-Order Streams 38

2.3 Stormwater Volume 39

2.4 The Water Quality Impacts of Land Development 40

Increased Pollutants in Urban Runoff 43

2.5 The Chemistry of Urban Runoff Pollution 44

2.6 Understanding Pollutant Transport in Stormwater 47

Stormwater Quantity and Quality 47

Particulates 48

Solutes 49

3 Land as the Resource 51

3.1 Historic Patterns of Land Development 51

3.2 Sustainable Site Design 58

3.3 Watershed Setting and Physical Context 58

3.4 Smart Growth Issues 59

Changes Related to Development 59

3.5 Conflict between Desired Land Use and Sustainability 61

3.6 Physical Determinants of Land Development 62

Geology 62

Physiography 65

Topography 66

Soil and Subsurface Conditions 67

3.7 Urban Communities with Combined Sewer Overflows 68

End of the Sewer 71

Other Urban Infrastructure 73

3.8 The Living Building and Zero Net Water Use 74

4 The Planning Process for LID 79

4.1 Sustainable Site Planning Process with Stormwater Management 79

Guideline 1: Understand the Site 79

Guideline 2: Apply LID Conservation Design 80

Guideline 3: Manage Rainfall Where It Originates 81

Guideline 4: Design with Operation and Maintenance in Mind 83

Guideline 5: Calculate Runoff Volume Increase and Water Quality Impacts 85

4.2 Overview of the Site Design Process for LID 86

5 The Legal Basis for LID: Regulatory Standards and LID Design Criteria 95

5.1 The Land–Water Legal Process 95

Common Law 95

Federal Water Quality Law 96

Federal Land Use Law 97

5.2 The Evolution of Land Development Regulation 98

5.3 The Regulatory Framework 100

Pennsylvania Land Use Law 101

Pennsylvania Water Law 102

California Land Use Law 103

California Water Law 104

5.4 Stormwater Management Regulations 105

Volume Control 105

Volume Control Criteria 106

Volume Control Guideline 108

Peak-Rate Control Guideline 108

Water Quality Protection Guideline 109

Stormwater Standards for Special Areas 110

Legal Implications of Green Infrastructure 110

6 LID Design Calculations and Methodology 113

6.1 Introduction to Stormwater Methodologies 113

6.2 Existing Methodologies for Runoff Volume Calculations 114

Runoff Curve Number Method 114

Small Storm Hydrology Method 117

Infiltration Models for Runoff Calculations 119

Urban Runoff Quality Management 119

6.3 Existing Methodologies for Peak-Rate/Hydrograph Estimates 120

The Rational Method 120

The NRCS (SCS) Unit Hydrograph Method 120

6.4 Computer Models 121

The HEC Hydrologic Modeling System 121

The SCS/NRCS Models: WinTR-20 and WinTR-55 121

The Stormwater Management Model 122

The Source Loading and Management Model 122

Continuous Modeling 123

6.5 Precipitation Data for Stormwater Calculations 123

6.6 Accounting for the Benefits of LID: Linking Volume and Peak Rate 124

6.7 Recommended LID Stormwater Calculation Methodology 124

Methods Involving No Routing 125

Methods Involving Routing 126

6.8 Nonstructural BMP Credits 127

7 Design of LID Systems 131

7.1 Nonstructural Measures 131

Impervious Surface Reduction 131

Limitation of Site Disturbance 132

Site Design with Less Space 132

7.2 Structural Measures 133

7.3 Pervious Pavement with an Infiltration or Storage Bed 134

Types of Porous Pavement 134

Description and Function 136

Pervious Bituminous Asphalt 141

Pervious Portland Cement Concrete 141

Pervious Paver Blocks 141

Reinforced Turf 143

Other Porous Surfaces 144

Potential Applications 144

Pervious Pavement Walkways (Concrete and Asphalt) 144

Rooftop and Impervious Area Connections 144

Water Quality Mitigation 145

7.4 Bioremediation 145

Rain Garden: Design and Function 146

Primary Components of a Rain Garden System 147

7.5 Vegetated Roof Systems 152

Design and Function 154

Design Elements of a Vegetated Roof System 155

Types of Vegetated Roof Systems 155

Dual Media with a Synthetic Retention Layer 158

Potential Applications 158

7.6 Capture–Reuse 158

Rain Barrels and Cisterns 161

Vertical Storage 164

8 Structural Measures: Construction, Operation, and Maintenance 169

8.1 Porous Pavement Systems 169

Construction 169

Storage/Infiltration Bed Dimensions 174

Construction Staging 174

Operation and Maintenance 176

Vacuuming 177

Restoration of Porous Pavements 178

Cost of Porous Pavement 178

8.2 Bioremediation Systems 179

Rain Gardens 179

Construction of a Rain Garden 183

Maintenance of Rain Gardens 183

Cost of Rain Gardens 184

Vegetated Roof Systems 184

Construction of a Vegetated Roof 187

Maintenance of Vegetated Roofs 188

Cost of Vegetated Roofs 188

8.3 Capture–Reuse Systems 188

Construction 188

Volume Reduction 191

Peak-Rate Mitigation 191

Water Quality Mitigation 191

Appendix A: The Stormwater Calculation Process 193

Appendix B: Case Studies 213

B.1 The Transition from Research to Practice 213

B.2 Manuals 215

B.3 LID Manual for Michigan (2008) 219

B.4 Models and Watershed Studies 237

B.5 Design and Construction Projects 251

Index 283