Designing Rainwater Harvesting Systems

CELESTE ALLEN NOVAK, FAIA, LEED AP, is a respected architect and principal at her Ann Arbor firm, Celeste Allen Novak Architect. She is widely published on sustainable design and rainwater harvesting. Her work on sustainable design and rainwater harvesting has appeared in Architectural Record and Green Source magazines.
 
G. EDWARD VAN GIESEN, MLA, ARCSA AP, is the National Sales Manager at BRAE/WATTS Rainwater Technologies. He brings real world experience as a designer and builder of countless rainwater systems. He is instrumental in the development of rainwater codes nationwide, and is an active participant with the ICC and IAPMO.
 
KATHY DeBUSK, PhD, PE, is an Assistant Professor of Environmental Science at Longwood University in Farmville, VA. Dr. DeBusk is an expert in the field of innovative rainwater harvesting design. Her research and consulting endeavors focus on the use of rainwater harvesting techniques to meet stormwater management goals.

Water conservation is one of the most effective sustainable design practices, yet few professionals know how to collect and use rainwater effectively. Rainwater Harvesting the first comprehensive book on designing rainwater harvesting systems. It provides practical guidelines for developing a rainwater harvesting strategy, taking into account climate, public policies, environmental impact, and end uses. Case studies are included throughout. Rainwater Harvesting is a valuable reference for architects, landscape architects, and site engineers.

Water conservation is one of the most effective sustainable design practices, yet few professionals know how to collect and use rainwater effectively. Rainwater Harvesting the first comprehensive book on designing rainwater harvesting systems.

Preface ix
 
Acknowledgments xiii
 
1 The Importance of Rainwater Harvesting 1
 
Water Capital 2
 
A Brief History of Centralized Water Systems 6
 
New Approach to Centralization--Decentralized Rainwater Systems 9
 
Examples from Around the World 11
 
India 11
 
Germany 13
 
The United States 16
 
Policy Issues and Sustainability 20
 
Water and Energy Savings 20
 
Response to Drought Conditions 23
 
Privatization and Relocation 25
 
Valuing Water Resources 25
 
History and Early Codes 25
 
Source 26
 
Value and Water Rates 27
 
Return on Investment 28
 
Challenges, Education, and Paradigm Shifts 34
 
Stereotypes and Preconceptions 34
 
Rainwater Technical Standard 34
 
Water Quality 35
 
Paradigm Shift 35
 
Endnotes 37
 
2 System Planning and Policies 39
 
Benefits That Drive Rainwater Harvesting Systems 39
 
Planning a System 40
 
Step 1: Identifying System Goals 46
 
Step 2: Codes, Standards, and Guidelines 49
 
Step 3: Incentive Programs and Rating Systems 63
 
Step 4: Educating and Involving the Stakeholders in the Design Process 71
 
Step 5: Putting It All Together 73
 
Endnotes 76
 
3 Water for Thirsty Buildings 79
 
Rainwater: Calculating Collection and Use 79
 
Step 1: Creating a Water Audit 82
 
Step 2: Calculating Annual Rainwater Supply 83
 
Step 3: Calculating Demand 89
 

Building Sectors, Sizes, and Demands 91
 
Small Office 91
 
Schools in Different Climate Regions 93
 
Step 4: Cistern Sizing 100
 
Alternative Water Sources 103
 
Other Wastewater and Recirculated Water 103
 
Plumbing Design and The Myth of Unlimited Water Supply 108
 
Thoughtful Planning Brings Success 111
 
Endnotes 113
 
4 System Elements 115
 
Integrated Approach 115
 
Opportunities for an Integrated Approach 117
 
1. Collection/Catchment Surface (Roof or Other) 118
 
2. Conveyance (Gutters and Downspouts) 123
 
Dry Conveyance versus Wet Conveyance 124
 
Sizing and Numbers 125
 
Aesthetics/Functions/Budget 126
 
Conveyance Functions 128
 
Conveyance Budget 128
 
3. Prestorage Filtration and Debris Exclusion 128
 
Prestorage Filter Types and Applications 128
 
Downspout Filters 130
 
Basket Filter 131
 
Centrifugal Filters 132
 
Cascading Debris Excluders 133
 
Prestorage Filtration Devises 134
 
Filter Sizes 134
 
How Components Help Merge the Goals of Rainwater and Stormwater 134
 
4. Storage 135
 
Aboveground Tanks 138
 
Belowground Tanks 139
 
Factors to Consider 140
 
5. Distribution 141
 
1. Pressurization 141
 
2. Filtration 141
 
3. Disinfection 143
 
4. Contoller 143
 
5. Automatic Protected Bypass 144
 
6. Makeup Supply 145
 
Integration, Thoughtful Planning, and Continuing Education
 
Are the Keys to Success 147
 
Endnotes 149
 
5 Maintenance and Safety 151
 
Water Quality of a Rainwater System 151
 
Sources of Pollutants 155
 
Fate and Transport of Pollutants in a Rainwater Harvesting System 158
 
Microbial Contamination 162
 
Addressing Water Quality for Various End Uses 163
 
First Flush 164
 
Water Testing Protocols 169
 
Using a Bypass / Backup Water Supply 170