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Page 1: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse
Page 2: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse
Page 3: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse
Page 4: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse
Page 5: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse
Page 6: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

NEW SOCIETY PUBLISHERS

Page 7: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

Cataloging in Publication Data:A catalog record for this publication is available from the National Libraryof Canada.

Copyright © 2007 by Heather Kinkade-Levario.All rights reserved.

Cover design by Diane McIntosh. Leaf/waterdrop: iStock.Inset photos: Heather Kinkade-Levario.

Printed in Canada.First printing April 2007.

Paperback ISBN: 978-0-86571-580-6

Inquiries regarding requests to reprint all or part of Design for Water shouldbe addressed to New Society Publishers at the address below.

To order directly from the publishers, please call toll-free (North America)1-800-567-6772, or order online at www.newsociety.com

Any other inquiries can be directed by mail to:

New Society PublishersP.O. Box 189, Gabriola Island, BC V0R 1X0, Canada1-800-567-6772

New Society Publishers’ mission is to publish books that contribute in fun-damental ways to building an ecologically sustainable and just society, andto do so with the least possible impact on the environment, in a mannerthat models this vision. We are committed to doing this not just througheducation, but through action. We are acting on our commitment to theworld’s remaining ancient forests by phasing out our paper supply fromancient forests worldwide. This book is one step toward ending globaldeforestation and climate change. It is printed on acid-free paper that is100% old growth forest-free (100% post-consumer recycled), processedchlorine free, and printed with vegetable-based, low-VOC inks. For furtherinformation, or to browse our full list of books and purchase securely, visitour website at: www.newsociety.com

NEW SOCIETY PUBLISHERS www.newsociety.com

Page 8: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

Foreword, by Bruce K. Ferguson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii

Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

1. Introduction to Rainwater Harvesting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

United States Green Building Council (USGBC) Leadership

in Energy and Environmental Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Rainwater Catchment History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2. A Rainwater Harvesting System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Components of a System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Catchment Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Conveyance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Roof washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Purification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

System Complexity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Water Budget . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Water Balance Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Cold Weather Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

3. Passive Rainwater and Stormwater Catchment. . . . . . . . . . . . . . . . . . . . . . . 47

A More Natural Approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Details for Passive Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4. Equipment for an Active Rainwater Catchment System . . . . . . . . . . . . . . . 65

Rooftops, Gutters, and Downspouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Downspout Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Contents | vii

Contents

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First-Flush Devices and Roof Washers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Downspout Diversion to a Rainbarrel or Rainchain . . . . . . . . . . . . . . . . . . 77

Storage Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Potable Water Treatment Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Examples of Handmade Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

5. Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Landscape Infiltration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Oregon Convention Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Seattle Natural Drainage System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Residential: Single-Family and Multi-Family RWH Systems . . . . . . . . . . 106

Cole Residence, Friday Harbor, WA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Kearney Residence, Tucson, AZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Rancho San Marcos, Santa Fe, NM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Camino Blanca, Santa Fe, NM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Single Family Quadplex, Tucson, AZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Casa Rufina Apartments, Santa Fe, NM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Residential: Subdivisions RWH Systems . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Rancho Viejo, Santa Fe, NM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Wilkes County Log Home Subdivision, Wilkes County, NC. . . . . . . . . . . . 117

Rancho Encantado Resort, Tesuque, NM . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Club Casitas de Las Campanas, Santa Fe, NM . . . . . . . . . . . . . . . . . . . . . . . 120

Commercial RWH Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Cabell Brand Store, Salem, VA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Eggleston Laundry, Norfolk, VA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

El Monte Sagrado Living Resort and Spa, Taos, New Mexico . . . . . . . . . . . 124

Earth Rangers Headquarters, Toronto, Canada. . . . . . . . . . . . . . . . . . . . . . . 127

Grand Prairie Animal Shelter, Grand Prairie, TX. . . . . . . . . . . . . . . . . . . . . 128

Lady Bird Johnson Wildflower Center, Austin, TX. . . . . . . . . . . . . . . . . . . . 131

Industrial RWH Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Ford Motor Co. Rouge Factory, Dearborn, MI . . . . . . . . . . . . . . . . . . . . . . . 134

Toyota Motor Sales, USA Inc, Portland, OR . . . . . . . . . . . . . . . . . . . . . . . . . 136

American Honda Corporation, Gresham, OR . . . . . . . . . . . . . . . . . . . . . . . 139

Kilauea Military Camp (KMC), Big Island of Hawaii . . . . . . . . . . . . . . . . . 142

School RWH Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

St Michael’s Parish Day School, Tucson AZ . . . . . . . . . . . . . . . . . . . . . . . . . 145

Roy Lee Walker Elementary School, McKinney, TX . . . . . . . . . . . . . . . . . . . 147

viii | Design for Water

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Heritage Middle School, Raleigh, NC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

Langston High School, Arlington, TX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

Stephen Epler Hall, Portland State University, Portland, OR . . . . . . . . . . . 153

Parks and Interpretive Centers RWH Systems . . . . . . . . . . . . . . . . . . . . . . 157

Kit Peak Observatory, Tohono O’odham Indian Reservation, AZ . . . . . . . 157

Carkeek Park, Seattle, WA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Chesapeake Bay Foundation, Annapolis, MD. . . . . . . . . . . . . . . . . . . . . . . . 162

Municipal RWH Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

San Juan Fire Station No.1, Friday Harbor, WA . . . . . . . . . . . . . . . . . . . . . . 164

First Green Post Office, Fort Worth, TX . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

Seattle City Hall, Seattle, WA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

King Street Center, Seattle, WA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

US Department of Agriculture Research Facility, Maricopa, AZ . . . . . . . . 174

Roanoke Regional Jail, Roanoke County, VA . . . . . . . . . . . . . . . . . . . . . . . . 176

North Carolina Legislative Building, Raleigh, NC . . . . . . . . . . . . . . . . . . . . 178

Alternate SourceWater Collection Systems . . . . . . . . . . . . . . . . . . . . . . . . 181

Air Conditioning Condensate and Cooling Tower Blowdown Collection . . 181

Fog Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

Greywater Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

Rainwater Harvesting for Wildlife . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Rainwater Catchment for Wildlife . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Appendix A: Resources List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

Appendix B: Metric Conversion Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

About the Author. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

Contents | ix

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RAINWATER COLLECTION linkshuman and environmental

systems in mutually reinforcinghealth. On-site, it supportshuman life by, in effect, gener-ating a new source of water.Upstream, it reduces the demandto develop off-site water sup-plies. Downstream, it protectswater quantity and quality byreducing excess urban runoffand the associated pollution,erosion, and flooding. The tech-nology and its applications areexpanding and being refined.Its applicability to both arid andhumid climates is becomingincreasingly clear.

Heather Kinkade-Levariohas made herself the leadingexpert in rainwater collection andits applications through a singu-lar combination of systematicobservation, focused academicstudy, and professional designexperience. Her native area is thearid Southwest, where the needfor water collection is most glar-ingly obvious and where the artof water catchment has devel-

oped most rapidly. She hasbeen a leader in the AmericanRainwater Catchment SystemsAssociation, the InternationalRainwater Catchment SystemsAssociation, and the US GreenBuilding Council.

Heather’s first book on thesubject—an award-winner in itsown right—was published notlong ago. But even since then,industry and design knowledgeand applications have evolvedand expanded. Advancementsare being developed at home inNorth America, and introducedfrom Europe. Professionaldemands have risen foradvanced technical informationand new types of applications.

This new book raises avail-able rainwater catchment,stormwater collection, and alter-nate water reuse information tothe detailed technical level andbroad scope of applicationrequired by professional archi-tects, landscape architects, andengineers. It gives us clear writ-ing, abundant case studies, great

Foreword | xi

Foreword

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illustrations, and technicalauthority. It is organized,comprehensive, and accessible.Through it we see where and howrainwater catchment is beingimplemented and alternate waterreused. We see at work bothsimple “passive” systems and thetechnically more demanding, buthydrologically much more com-

plete and efficient, “active”systems. This new book elevatesprofessionals’ awareness andcapability by providing theinformation they need.Immediately upon publication,it has the effect and stature ofthis growing technology’s leadingtechnical guideline and profes-sional information resource.

— BRUCE K. FERGUSON, FASLAFranklin Professor of Landscape Architecture and former

Director, University of Georgia School of Environmental DesignAuthor, Stormwater Infiltration, Introduction to Stormwater,

and Porous Pavements

xii | Design for Water

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COLLECTING AND STORING

rainwater is not a new idea.For almost 4000 years, culturesthroughout the world have usedcaptured rainwater. King Meshaof Moab won his war in hisquest for land east of Jordan dueto making reservoirs for catchingwater, the water that allowedhim to survive through drytimes. Wars have been foughtand won over ownership ofwater or the ability to catch rain-water. It has even been said that

water may be the oil of the 21stcentury. Continuing this thoughttoday, collecting and using watermore than one time can helpreduce dependence on existingfresh water supplies. Much ofthe municipal water that hasbeen purified to drinking waterstandards is used for tasks suchas house cleaning, flushing toi-lets, gardening, and washingclothes or cars when drinking-water quality for these tasks isnot required.

Preface | xiii

Preface

World Birding Center:One of 18 water tanks that storea total of 45,000 gallons

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Collecting rainwater,stormwater or an alternate waterthat has been used one time andcan be used a second time withlittle or no treatment couldprovide a new water supply,saving the purified municipalwater for high-quality waterneeds. Rainwater alone can helpto improve poor-quality water,augment inefficient or unde-pendable water supplies, cleansesoil by leaching built-up saltdeposits, avoid the need formunicipal chlorination andfluoridation treatments, andreduce or eliminate the cost ofobtaining an alternate watersupply. Drilling a well, laying apipe for long distances, trench-ing in rocky conditions, orpumping water to higher eleva-tions may prove to be too costly.In these and other instances,rainwater and stormwatercollection as well as alternatewater reuse can offer a morecost-effective water supply.

This potential supply ofwater is especially important inall arid and semi-arid regionswhere rainfall is neither frequentnor reliable. Collecting the waterthat falls onto a designated sitethen retaining that water and/orusing water that is generatedon site for on-site needs can beimportant for the sustainabilityof any design or development ofa localized area. Applied consis-tently over the course of severalprojects, this water supply canhave regional importance for theconservation of limited groundand surface water supplies.

Two water sources thatpotentially need very littlefiltration or purification arerainwater and fog condensate.However, both require specifictechniques for collection. Fogcollection, while it can onlyapply to specific elevationsand geographic fog-producingfeatures, requires large fog col-lection arrays, troughs, pipes,

World Birding Center:Wildlife guzzler fed by anadjacent rainwater tank C

.R.H

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xiv | Design for Water

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and water storage tanks.Similarly, the efficient collectionof rainwater depends on severalfactors. First of all, the catch-ment area—the defined surfacearea upon which rainwater fallsand is collected—should becarefully chosen. Pollutantsintroduced from a poorly chosencatchment area can affect the

usability of the captured water.Second, the quantity of waterto be collected, known as therainwater harvesting potential,should be carefully evaluated.Third, the conveyance systemthat carries the water to storagemust be designed, and an initialprocess of removing pollutants,known as a first-flush diversion

Preface | xv

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World Birding Center:A 2,400-gallon tank

World Birding Center:A tank next to the archedroof catchment that feeds theadjacent wildlife pond

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or roof washing, must be consid-ered. The water must also bestored and then distributed bygravity or by pumping.

Stormwater catchment can befor reuse of the water or, moretypically, it can be caught forinfiltration purposes. Alternatewater supplies such as coolingtower bleed-off water, air condi-

tioning condensate, and greywatercan and typically are reused fornon-potable uses that includelandscape irrigation and toiletflushing. While rainwater collec-tion is the main emphasis of thisbook, the collection and use orreuse of all of these supplies arerecommended for applicabilityto a new or existing project.

xvi | Design for Water

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IT IS TIME THAT WE TAKE ourfutures and our children’s

futures seriously and start pro-viding solutions today fortomorrow’s world. One specificand very serious issue is fresh-water supplies. It is out of thisdesperate need for understand-ing and examples of how we canextend our current resources forfuture generations that this bookhas been assembled.

Thank you to all projectowners, designers, and buildersthat have taken a chance to trysomething new and innovativein the quest to conserve waterfor my child and yours.

Thank you, Victoria, foryour graphic support and keep-ing the standards high.

Acknowledgments | xvii

Acknowledgments

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Page 20: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

IN MARCH OF 2005 theMillennium Ecosystem

Assessment (MEA) was released.This report, requested by UnitedNations Secretary-General KofiAnnan in 2000, is titled LivingBeyond Our Means: NaturalAssets and Human Well-Being.The report is a culmination ofthe findings of 1,360 expertsfrom across the world. Theirfindings focus on the conditionand trends of the ecosystems,scenarios for the future, possible

responses, and assessments ata sub-global level. The mainmessage presented by thisgroup is one of warning, statingthat human activity is puttingan incredible strain on thenatural functions of the Earth,one that we can no longerignore. The team of expertsargues that we must learnto recognize the true valueof nature and the protectionof these natural assets can nolonger be seen as an option.

Irrigation of theland with seawaterdesalinated by fusionpower is ancient.It is called Rain.

— Michael McClary

Spring rainclouds

Introduction toRainwater Harvesting

HEATH

ER

KIN

KAD

E-L

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1 “”

Introduction to Rainwater Harvesting | 1

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Freshwater is one natural assetlisted as a priority.1

People use a lot of water fordrinking, cooking, washing, andirrigating landscapes. They useeven more water to producefood, material products, manu-factured items such as clothing,and to run buildings. The totalamount of freshwater consumedby an individual, business, ornation to produce goods andservices is known as the waterfootprint of that individual,business, or nation.2 In an effortto reduce our collective fresh-water footprint, this bookpresents options for water sup-plies beyond groundwater andsurface water that help to reducethe amount of these water types

withdrawn and purified for useby humans. There are manytypes of water included in thefollowing definitions:

• Atmospheric water – Rainand fog.

• Blue water – Water fromaquifers, rivers, and lakes.3

• Green water – Soil moisture.4

• Stormwater – Rainwater thathas hit the ground.

• Greywater (Graywater) –Wastewater from a laundry,bathtub, shower, and/or abath sink.5

• Alternate water – Water thathas been used previously,typically by equipment,including cooling tower bleed-

2 | Design for Water

Feather and Fur AnimalHospital rainwater tank,

Austin, TX BIL

LH

OFF

MAN,A

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INU

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ITY

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off water, air-conditioningcondensate, and water usedin labs to cool equipment.

• Black water – Water fromtoilets and kitchen sinks.

• Reclaim water – Water that hasgone through a sewer treat-ment process and has beenfiltered and processed for

reuse in various ways, includ-ing large scale irrigation.

We need to change the waywe use our freshwater and needto look at our designs thatinvolve water to use what wehave as efficiently as possible.Therefore, we must “design forwater.” While the main focusof this book is on rainwater

Introduction to Rainwater Harvesting | 3

Passive rainwater harvesting:Island Wood School, Seattle, WA

HEB store displays rainwatertanks at their entry road, Austin, TX

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collection for potable and non-potable use, the case studiespresented will discuss watercollection for infiltration andincreasing green water, fog col-lection, stormwater catchment,and alternate water reuse—including greywater reuse.The case studies presented willdemonstrate that freshwater—blue water—does not have tobe the first choice for a watersource, which means we canreduce our water footprint.

United States Green BuildingCouncil (USGBC) Leadership inEnergy and EnvironmentalDesign (LEED)Many of the projects presentedin this document have attaineda specific green building levelof LEED Certification. Thedesignation of Certification,Silver, Gold, or Platinum meansthat the project has met all thecriteria set by USGBC for thesevarious LEED levels. The

USGBC Preamble released May25, 2006 states the following:

“Whereas USGBC is dedicat-ed to improving conditionsfor humanity and nature,honoring and enhancing theprospects for both throughthe creation of a built envi-ronment that is mutuallybeneficial, we herebyacknowledge our allegianceto the essential values:

Sustainability: Respect thelimits of natural systems andnon-renewable resources byseeking solutions that producean abundance of natural andsocial capital;

Equity: Respect all commu-nities and cultures and aspireto an equal socio-economicopportunity for all;

Inclusiveness: Practice andpromote openness, broadparticipation, and full con-sideration of consequence

4 | Design for Water

Reunion Building with two4,400-gallon rainwater tanks JA

CK

HALL,S

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LLP

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in all aspects of decision-making processes;

Progress: Strive for immediateand measurable indicatorsof environmental, social, andeconomic prosperity;

Connectedness: Recognizethe critical linkage betweenhumanity and nature as well

as the importance of place-based decision-making toeffective stewardship.”

The more the points met bythe buildings, the higher thelevel up to the maximum pointsfor a Platinum rating. More canbe found on this subject atwww.usgbc.org.

Introduction to Rainwater Harvesting | 5

Passive rainwater harvesting:Pima Community College FPlaza gutter drops to splash padof rocks next to a tree

Passive rainwater harvesting:Pima Community College swalenext to sidewalk collects storm-water runoff for vegetation

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Rainwater Catchment HistoryMany cultures throughout theworld have used captured rain-water. The Middle East, Asia,ancient Rome, and Mexico uti-lized rainwater harvesting. InIndia, simple stone-rubble struc-tures for capturing rainwaterdate back to 3000 BC.6 A civiliza-tion as early as 2000 BC survived

in the Negev Desert of what isnow Israel by storing hillsiderunoff in cisterns.7

A historical document ofthe time mentions water cisternsand the habit of having at leastone rainwater-collecting cisternper home that would range insize from 35 to 200 cubic meters.These residential cisterns were

6 | Design for Water

Istanbul, TKcistern sign K

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Inside theIstanbul cistern

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typically below ground and werepear or bottle shaped.8 The firstcommunity cisterns ranged insize from 4,000 cubic meters tolarge reservoirs such as the onefound in Madaba that couldhold 42,750 cubic meters. Thesecisterns were technologicallysophisticated with sedimenttraps or “first-flush” systems tocatch sediment, mud, and sandprior to allowing the water toenter the cistern.9 Huge rockhewn cisterns and canals can befound in Petra. In all of theselocations, rainwater was typicallycollected off rooftops and plazas.

In Rome, rainwater wascollected from the coveredwalkways and diverted to smallpools located in gardens foresthetic purposes and for futureuse as irrigation water.10 TheRomans designed villas andentire cities to take advantageof collected rainwater and theyused the water as the primarysource for drinking and other

domestic uses.11

Underground cisterns incentral Mexico stored collectedrainwater from plazas androoftops for human consump-tion and irrigation.12 In theYucatan Peninsula, archaeolog-ical remains from AD 300indicate ground catchmentsystems known as Chultunswere used to collect rainwater.13

In the United States and Canada,rainwater collection systemshave historically been used bynative inhabitants and settlersin isolated areas where therewere no existing municipal watersupplies. In many areas they arestill used, as demonstrated by a1995 survey, which concludedthat in that year there wereroughly 250,000 rainwater har-vesting systems in use in theUnited States.14 Rainwaterharvesting systems are currentlygaining popularity as manycommunities promote sustain-able development.

Introduction to Rainwater Harvesting | 7

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8 | Design for Water

Mexican home with acorrugated metal cistern

next to the house, used forvegetables in the front yard H

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Belize rainwater tank atthe end of a driveway

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Throughout this book, youwill notice that volumes,weights, costs, and other meas-ures are referenced. Unlessotherwise noted, these are pre-

sented in standard US measure.There is a metric conversiontable in an Appendix at the endof the book for most measure-ment conversions.

Introduction to Rainwater Harvesting | 9

Hawaiian rainwatertankT

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10 | Design for Water

Page 30: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

RAIN, A FORM of precipitation,is the first form of water in

the hydrologic cycle, the contin-uous circulation of water in theearth-atmosphere system. Rainis the primary source of waterthat feeds rivers, lakes, andgroundwater aquifers. Rivers,lakes, and groundwater are allsecondary sources of water.Currently, most of us dependentirely on secondary sources forour water supplies. The value ofrainwater, the primary source of

water, is typically ignored.Rainwater catchment directlyresponds to the value of thisprimary source of water, mak-ing optimal use of rainwaterwhere it falls.

Rainwater collection hasbeen used for several thousandyears as a way to take advantageof seasonal precipitation thatwould otherwise be lost torunoff or evaporation. Whilerainwater can provide water formany uses, the most common

Arguments overwater are resolvedby rain.

— Japanese proverb

LEFT:Rain scupper on acommercial buildingRIGHT:Corrugated metal pipecistern located within awalled residential patio

A RainwaterHarvesting System

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2 “”

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use is for agricultural irrigationand residential potable water.Most applied definitions of rain-water collection, or rainwaterharvesting as it is typicallyreferred to, detail numerousmethods for collecting, storing,and conserving runoff from anassortment of sources for unlim-ited purposes in arid andsemi-arid regions.15

One definition of rainwaterharvesting states that the word“harvesting” refers to a processthat first requires a method of“seeding” the clouds to inducethe rain.16 For the purposes ofthis book the word harvestingwill refer to the collection of rainwithout an artificial inducement.The aim of rainwater harvestingis to concentrate runoff and col-lect it in a basin or cistern to bestored for future use.

Rainwater captured from roofcatchments is the easiest and mostcommon method used to harvestrainwater. It is, however, not the

only harvesting method. Rainwatermay be collected from any hardsurface, such as stone or concretepatios, and asphalt parking lots.Typically, once the rain hits theground it is no longer referred to asrain, but as stormwater. Landscapescan also be contoured to retainthe stormwater runoff.

There are numerousidentified benefits of watercatchment from either rooftopor ground level:

• It provides a self-sufficientwater supply located close tothe user.

• It reduces the need for, andhence the cost of, pumpinggroundwater.

• It provides high-quality softwater that is low in mineralcontent.

• It augments the supply andimproves the quality of ground-water when it reaches theaquifer after it has been appliedto the landscape or crops.

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Rooftopcatchment H

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• It reduces and may even elimi-nate soil salts as it dissolvesand moves the salts downthrough the soil.

• It mitigates urban floodingand, as a result, reduces soilerosion in urban areas.

• Rooftop rainwater harvestingis usually less expensive thanother water sources.

• Rooftop rainwater harvestingsystems are easy to construct,operate, and maintain.

• In coastal areas where saltwater intrusion into theaquifer is a problem, rainwaterprovides good quality water,and when recharged togroundwater, reducesgroundwater salinity whilehelping to maintain a balancebetween the fresh and salinewater interface.

• On islands with limitedfresh-water aquifers, rain-water harvesting is thepreferred source of water fordomestic use.

• Occasionally, there are econom-ic advantages such as rebatesfrom municipalities for areduction in use and depend-ency on municipal water.

Rainwater harvesting andstormwater catchment consistsof up to six primary compo-nents depending on the degreeof water quality required. Thesecomponents include catchment,conveyance, filtration, storage,

distribution, and purification, allof which are defined in the nextfew pages. The amount of watercollected depends on catchmentsize, surface texture, surfaceporosity, and slope conditions.Regardless of the catchment sur-face material, a loss of from 10to 70 percent may be expecteddue to runoff material absorp-tion or percolation, evaporation,and inefficiencies in the collec-tion process.

There are numerousways to connect the catchmentareas to the desired point of useor to a landscape holding area.A landscape holding area, essen-tially a passive stormwaterdistribution system, is an earthbasin that is used to irrigateplants through an overland flowsystem: water infiltrates throughthe soil and is then conservedin a plant’s root zone—greenwater—for its consumptive use.Distribution systems that directrainwater and stormwater runoffcan be as simple as landscapeswales, sloped sidewalks, andconcrete street gutters, or theycan be sophisticated systemssuch as roof gutters anddownspouts, collection anddistribution systems for sub-asphalt collection, filters and acistern to delay or control dis-tribution of rainwater runoff,perforated pipes and drip irriga-tion, or pumps to move andtreatment systems to purify thecollected water.

A Rainwater Harvesting System | 13

Downspout and gutteron a residential roof

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Components of a SystemWhether it is large or small, arainwater harvesting system hassix basic components:

1. Catchment area: the surfaceupon which the rain falls. Itmay be a roof or imperviouspavement and may includelandscaped areas.

2. Conveyance: channels orpipes that transport thewater from catchment areato storage.

3. Roof washing: the systemsthat filter and remove con-taminants and debris. Thisincludes first-flush devices.

4. Storage: cisterns or tankswhere collected rainwater isstored.

5. Distribution: the system thatdelivers the rainwater, eitherby gravity or pump.

6. Purification: includes filter-ing equipment, distillation,and additives to settle, filter,and disinfect the collectedrainwater.

Purification is only requiredfor potable systems and wouldtypically occur prior to distri-bution. Details 2.1 and 2.2illustrate a nonpotable processfor commercial and residentialapplications.

Catchment AreaA catchment area is the definedsurface area, typically a rooftop,upon which rainwater falls and

is eventually collected. Rainwaterharvesting for nonpotable usecan be accomplished with anytype of roofing material. Forpotable use, the best roof mate-rials are metal, clay, and concrete.Water for drinking purposesshould not be collected from roofscontaining zinc coatings, copper,asbestos sheets, or asphalticcompounds. Roofs with leadflashings or painted with lead-based paints should not be used.An acceptable roofing materialfor systems that will be catchingwater intended for human con-sumption is Raincoat 2000. It isa three-part roof coating prod-uct for flat or semi-flat roofs thatis approved by the NationalSanitation Foundation (NSF) forpotable water harvesting.

Although rooftops are thetypical catchment area, patiosurfaces, driveways, parking lots,or channeled gullies can alsoserve as catchment areas.However, because of the higherrisk of contamination, stormwa-ter collected from ground-levelcatchment areas should not beused for potable purposes unlessa purification system accompa-nies the distribution system.

Rainbarn is a term describ-ing an open-air shed or ramadadesigned with a large roof area,the sole purpose of which is tocatch rainwater. The structure’slarge roof area could also pro-vide shelter for a variety ofuses—a patio, carport, hay

14 | Design for Water

Flat rooftop catchment areafinished with Raincoat 2000

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storage, or farm equipment stor-age—thereby serving multiplefunctions. Typically, a cistern ishoused under a rainbarn.17

Rainwater is slightly acidic,which means it will dissolve andcarry minerals into the storagesystem from any catchment sur-face. When a system is intendedfor potable water collection,the first step should be to testthe water collected from theproposed catchment surface todetermine its content and whatitems need to be removed by a

filtration system or if the catch-ment surface needs to be altered.

The total amount of waterthat is received in the form ofrainfall over an area is called therainwater endowment of that area.The actual amount of rainwaterthat can be effectively harvestedfrom the rainwater endowmentis called the rainwater harvestingpotential.18 Rainwater yieldsvary with the size and texture ofthe catchment area. A maximumof 90 percent of a rainfall canbe effectively captured through

A Rainwater Harvesting System | 15

Rainwater harvestingprocess

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16 | Design for Water

Detail 2.1Typical components of a commercial/industrial building rainwater harvesting

NOTE: Cistern size and catchment area should be balanced for maximum accumulated storage. Not all site rainfall should be directed to cistern, only the quantity required to maintain the proposedlandscape irrigation budget.

1. Single-plane or double-plane butterfly rooftop collection.

2. Optional decorative scupper cover.

3. Scupper to downspout.

4. Downspout sized per local plumbing code, sediment trapat ground level.

5. Catchbasin for paved/hard surface ground level runoffcollection, with sediment trap.

6. Debris, sediment, and oil interceptor.

7. Rainwater inlet. Inlet to cistern must be a minimum of10 inches below top of cistern. An inflow smoothing filtermay be appropriate at this location depending on prox-imity of rainwater inlet to irrigation supply filter. Thesmoothing filter will slow rainwater inlet turbulence thatmay disturb the fine sediment settled on the bottom ofthe cistern.

8. Maximum water level to be 12 inches below top ofcistern.

9. Minimal level of water to maintain priming in landscapeirrigation pump (approximately 12 inches), level of waterto be determined by engineer or irrigation specialist.

10. Landscape irrigation supply filter with automatic shutoffto maintain priming in pump if water falls below mini-mum level in cistern. Locate filter a minimum of 6 inchesfrom cistern bottom to avoid settled fine sediment.

11. Cistern overflow (same size as inlet) to a dry well orgravity outlet to landscape basin if site conditions allow.An additional option would be to outlet to an adjacentflood retention underground storage pipe that is tied toa dry well. Cistern overflow must be a minimum of 12inches below top of cistern to avoid contamination ofalternate water supply (if proposed).

12. Sand filter (optional).

13. Landscape irrigation pump and pressure tank.

14. Typical valve.

15. Water supply line for irrigation system.

16. Thirty-two inch access for cleaning.

17. Twenty-four inch access for cleaning.

18. Alternate water supply, must not obstruct the 24-inchaccess. Alternate water supply may be proposed for acistern manual fill option for droughts and plant estab-lishment periods when additional water is required.Alternate water supply may also be automatic for filloption when rainwater supplies are inefficient.

19. Atmospheric vacuum breaker.

20. Typical valve.

21. Alternate water source, possibly domestic or municipalsupply.

22. Gutter with leaf screen if building is adjacent to trees.

23. Rainchains or downspouts to splash pads and depressedlandscape areas.

24. Splash pad.

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A Rainwater Harvesting System | 17

Detail 2.2Typical components of a residential building rainwater harvesting system for landscape irrigation

NOTE: Both above-grade and below-grade cisterns are shown. For residential systems, either may be appropriate. It is not necessary to have both types of systems. Cistern size and catchment areashould be balanced for maximum accumulated storage. Not all site rainfall runoff needs to be directed to cistern, only the quantity required to maintain the proposed landscape irrigation budget.

1. Rooftop collection.

2. Gutter with leaf screen if building is adjacent to trees.

3. Five- to six-inch gutters, sized per local plumbing code.

4. Downspout sized per local plumbing code, sediment trapfor ground-level catchment or direct to cistern.

5. Pipe to cistern, typically 4-inch diameter schedule 40 PVCpipe.

6. Debris and sediment interceptor, first-flush device.

7. Screw-off end cap for cleaning.

8. Catchbasin for paved/hard surface ground-level runoffcollection, with sediment trap.

9. Rainwater inlet, inlet to cistern must be a minimum of10 inches below top of cistern. An inflow smoothing filtermay be appropriate at this location depending on prox-imity of rainwater inlet to irrigation supply filter. Thesmoothing filter will slow rainwater inlet turbulence thatmay disturb the fine sediment settled on the bottom ofthe cistern.

10. Maximum water level to be 12 inches below top ofcistern.

11. Minimal level of water to maintain priming in landscapeirrigation pump (approximately 12 inches), level ofwater to be determined by engineer or irrigation special-ist.

12. Twenty-four inch access for cleaning.

13. Alternate water supply, must not obstruct the 24-inchaccess. Alternate water supply may be proposed for acistern manual-fill option for droughts and plant estab-lishment periods when additional water is required.Alternate water supply may also be automatic for filloption when rainwater supplies are inefficient.

14. Typical valve.

15. Atmospheric vacuum breaker.

16. Alternate water source, possibly domestic or municipalsupply.

17. Cistern overflow (same size as inlet) to a dry well orgravity outlet to landscape basin if site conditions allow.An additional option would be to outlet to an adjacentflood retention underground storage pipe that is tied toa dry well. Cistern overflow must be a minimum of 12inches below top of cistern to avoid contamination ofalternate water supply, or be 6 inches below any debrisstrainers in an above-grade cistern.

18. Landscape irrigation supply filter with automatic shutoffto maintain priming in pump if water falls below mini-mum level in cistern. Locate filter a minimum of 6 inchesfrom cistern bottom to avoid settled fine sediment.

19. Optional sand filter.

20. Landscape irrigation pump and pressure tank.

21. Typical valve.

22. Water supply line for irrigation system.

23. Removable leaf and debris strainer basket.

24. Hose bib for draining cistern.

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rooftop rainwater harvesting.The quality of the captured rain-water depends, in part, uponcatchment texture: the bestwater quality comes from thesmoother, more imperviouscatchment or roofing materials.

Captured rainwater qualityis also determined by rainfallpattern and frequency. Both thegreater the storm event, i.e., therainfall extent and the quantityof rain that falls, and the shorterthe time between storms influ-ence the cleanliness of thecatchment area. Greater rainwa-ter volumes and frequencies willtransport fewer pollutants to thefirst-flush device (describedbelow in the Roof Washing sec-tion) or the storage unit.

ConveyanceA commonly used rainwaterconveyance system is comprisedof gutters with downspoutsand/or rainchains. Gutters anddownspouts direct rain fromrooftop catchment surfacesto cisterns or storage tanks.Rainchains are lengths of chainthat hang from gutters anddirect rainwater down theirlengths, thereby minimizingsplash. In the rainwater harvest-ing process, they may be usedwhen water is being collected forbelow-grade storage or directedto a landscaped area.

Gutters and downspouts canbe easily obtained as standardhousehold construction materi-

als, or they can be specificallydesigned to enhance a buildingfaçade and maximize theamount of harvested rainfall.The materials for gutters anddownspouts range from vinyland galvanized steel to alu-minum, copper, and stainlesssteel. Gutters should typicallybe square, rectangular, or halfround in shape and, at a mini-mum, 5 or 6 inches wide. Theyshould have an outer edge high-er than the roof-side edge, havesplash guards at roof valleys,slope towards downspouts atone-sixteenth to one-quarterinch per 10-foot length of gutter,and be installed per manufactur-er’s guidelines for hangers andconnection points (approxi-mately one bracket every 30inches).

A typical connection materi-al from a downspout to a cisternis a 3- or 4-inch diameter sched-ule 40 PVC pipe or the moreenvironmentally sensitive ABSpipe. For potable rainwater col-lection, only schedule 40 PVCshould be used, as it is the onlyPVC made from “virgin” materi-al—i.e., material made from newmaterial, not recycled materialthat may have picked up con-taminants from its previous use.Coated aluminum downspoutsare acceptable for potable collec-tions. No ABS, DWV PVC,copper, lead-containing, or gal-vanized pipes should be used forpotable collections. Downspouts

18 | Design for Water

Gutter and downspout ona residential building

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Gutter and downspoutattached to cistern

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should be placed as appropriateto allow 1 square inch of outlet(downspout) space for every 100square feet of roof area to bedrained. As an example, a 4-inchdiameter downspout can drainapproximately 400 square feet ofroof area.

There are two types of con-veyance systems, wet and dry. Awet system involves downspoutsthat lead to a storage systemwhere standing water is main-tained; downspouts run downthe wall and underground andthen up into the tank. In a drysystem, the downspouts draindown into the storage system,thus eliminating any standingwater in the conveyance systemafter a rain event. Dry systemsreduce the potential of mosquitohabitat and are the type of sys-tems detailed in this book.

Gutters should be kept cleanand debris-free to maintain thelongevity of the gutter material—clean gutters dry out after arain faster and dry gutters lastup to three times longer thanwet gutters, which equates to asignificant cost savings. TheUniform Plumbing Code hasan appendix dedicated to rain-water systems, with guidelinesto size gutters, downspouts, andlateral pipes. The applicableplumbing code should bereviewed for any design ofrainwater conveyance systems.

To keep leaves and otherdebris from entering a rooftoprainwater harvesting system, thegutters should have continuousleaf screens made out of one-quarter-inch wire mesh screenin a metal frame or an equallyefficient product covering the

A Rainwater Harvesting System | 19

Mobile trailer under a rainbarnthat is attached to a cistern

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Rainbarns used forrainwater collection systems

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entire length of gutter. Installingleaf screens will help reduce arainwater harvesting system’smaintenance, eliminate flamma-ble material from the roof area,reduce mosquito breeding habi-tat, and eliminate the need forfrequent and potentially haz-ardous use of a ladder to cleanthe gutters.

Roof WashingRoof washing is the initial processin reducing the debris and solublepollutants that may enter a rain-water harvesting system. Roof-washing systems may use one orseveral components to filter orcollect debris and soluble pollu-tants, including gutter leafguards, rainheads, screens, and/

20 | Design for Water

LEFT:Rainchain used by a

commercial building to directrainwater to the landscape

RIGHT:Rainchain splash pad H

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Specifications ona plastic tank

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or first-flush devices (describedlater). Use of the first three ofthese allows the maximumamount of rainwater that encoun-ters the filtering unit to beharvested while removing debris.Use of first-flush devices isimportant when rainwater is col-lected without the use of gutterleaf guards, leafslides, or rain-

heads, or if the rainwater is to beused for human consumption.

Roofs, like other large, exposedareas, continuously receivedeposits of debris, leaves, silt,and pollutants on their surface.All rainwater dislodges and carriesaway some of these deposits,but, during any given rainfall,the stormwater that falls first

A Rainwater Harvesting System | 21

Empty tanks under awooden deck readyfor installationH

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A 240-gallon collectiontank from which collectedrainwater is pumped to aremote storage tank

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At-grade concretecistern

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carries the highest concentrationof debris and soluble pollutants.First-flush devices collect anddispose of this initial rain beforeit contaminates previously har-vested and stored rainwater.

Terry Thomas, a specialist inrooftop rainwater harvesting, isthe Director of the DevelopmentTechnology Unit at the Schoolof Engineering at the Universityof Warwick in England. He hasidentified several reasons forreducing debris and silt thatmay enter a rainwater storagesystem, including:

• Reduction of frequency oftank cleaning

• Reduction of bacterial inflowthat is often attached to solids

• Reduction in the nutrient lev-els in cisterns/tanks that, inturn, reduces or even elimi-nates mosquito larvae growth

• Reduction in organic loading,creating less of a chance of

anaerobic conditions and odorin the cistern/tank

Roof-washing systems pro-vide a means of accomplishingthese objectives. The simplestroof-washing system is a first-flush device that consists of astandpipe, the container forcollecting the initial rainwaterrunoff, and a gutter downspoutlocated prior to the cistern orstorage tank inlet. Because atypical standpipe does not auto-matically outlet to a storm drain,a screw-on cleanout plug shouldbe located at the end of thestandpipe. The standpipe shouldbe emptied after each rain eventto prepare for future use andto eliminate the standing waterfrom becoming foul and stag-nant due to its content of debrisand soluble pollutants, andthereby contaminating futurecollected rainwater.

A German company hasdeveloped a simple and self-

22 | Design for Water

Roof washer on display forpurchase at a rainwater harvest-

ing systems supply company

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Blue Mountain Meshall-steel gutter mesh covering

a gutter on a tile roof SAN

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cleaning filter—called a WISYfilter—that combines the stand-pipe/downspout componentsof a roof-washing system. Thissystem does not flush the firstgallons of collected rainwater asdoes a typical standpipe, which,if the rainwater is proposed forpotable use, may mean morepurification will be requiredbefore the stored rainwater isused for human consumption.Instead, the WISY filter, with itsinterior lining of fine mesh,diverts up to 90 percent of therainwater from the enhancedstandpipe to the storagetank/cistern while allowing theremainder to pass on through,carrying the unwanted leaves,debris, and silt into the stormdrain or an adjacent landscape.

Capacities of first-flushdevices may vary depending onthe catchment size and ultimateuse of the rainwater. Rainwatercollected from a rooftop willtypically be cleaner than storm-water collected from a surface orpavement area, which means thestorage capacity of the first-flushdevice does not need to be large.Stormwater collected from sur-face or pavement areas mayrequire longer settling periodsfor suspended solids and anabsorbent pillow to remove oiland grease; therefore, a moresophisticated and larger capacityfirst-flush device is required.

A first-flush device for smallrooftops (less than 1,000 square

feet) should provide storagecapacity for diversion of the first5 gallons of collected rainwater.Larger rooftops should provide acontainer for diversion of theinitial 10 gallons of rainfall per1,000 square feet of roof area.With very large rooftops orpaved catchment areas (one acreor more), a maximum of 500(or 1,000 if collected from dirtypavement) gallons for each rainevent should be collected anddisposed of in a first-flushdevice. Some residential roofwashers are self-cleaning andadjust to the amount of rainreceived or the rate at which the

A Rainwater Harvesting System | 23

WISY filter display:black pipe leadsto cistern

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Detail of WISY filter

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rainwater enters the roof wash-ing device.

Use of a first-flush device isespecially important when a rainevent follows a long period of norain, since, during dry spells,debris and other pollutants buildup on catchment surfaces. Inthis case, a large volume of watermay be required to remove thecatchment surface contaminants,possibly surpassing the volumeallowed in a specified first-flushdevice. This means some con-taminants will not be divertedand will be allowed to enter therainwater storage system. When asecond rain event closely followsone that was strong enough tosufficiently wash the catchmentarea, use of the first-flush device

during the second rain eventmay not be required.

However, if the first rainevent was not strong enough tomove the catchment area con-taminants, diversion of thesecond rain event’s initial rain-water runoff to the first-flushdevice may be warranted, partic-ularly if it is potable water that isto be protected from contami-nants. Where potable water isnot the issue, a second first-flushmay only waste valuable rainwa-ter. Instead, collection in thecistern may be warranted, espe-cially for non-potable uses suchas landscape irrigation, laundry,toilet flushing, etc. Some first-flush devices such as theSafeRain will reset and fill fasterwith a second close rain event,thereby wasting less rainwaterfrom an already clean roof.

A roof-washing system gen-erally produces the best resultswhen combined with the use offiltering devices on gutters, down-spouts, and first-flush devices.This is especially true whenpotable water is the desired endproduct. The most commonfiltering devices are gutter leafscreens, which filter large leavesand other debris. However,because leaf screens are notdesigned to filter smaller matter,water released from the gutterswill often contain fine debris oreven dissolved contaminants.

Fortunately, the filteringprocess can be augmented by use

24 | Design for Water

German product display:rainhead filter

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German product display:cistern overflow attached

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German product display:cistern inlet filter

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of a downspout that incorporatesa self-cleaning system called arainhead. A rainhead is a squarefunnel topped by a screen set atan angle of about 33 degrees tothe lower horizontal edge of thefunnel. As the water washes overthe angled screen, the debris isforced toward the screen’s loweredge and away from the building,while the rainwater continuesthrough the funnel screen.

Rainheads can be used witheither a dry or a wet rainwaterconveyance system. For usewith a wet system, an Australiancompany has designed the LeafBeater system, which provides asecond horizontal screen thatprevents mosquitoes from enter-ing the conveyance system andreaching the storage tank/cistern.A Leafslide box may also be used.The box works in the same man-ner as the rainhead by allowingthe rainwater’s vertical drop toclean the filter. The Leafslideachieves best results when two

sections of the guttering systemare diverted simultaneouslythrough the box. As noted, thecombining of filtering methodssuch as gutter leaf screens, leaf-slides, rainheads, and first-flushdevices is desirable when theharvested rainwater is intendedfor human consumption. Whenthe collected rainwater is to beused solely for landscape irriga-tion, only the large debris mayneed to be filtered, as someitems, such as bird droppings,may be beneficial to the plantsreceiving the rainwater.

StorageMost of the components of arooftop rainwater harvestingsystem are assumed costs in abuilding project. For example,all buildings have a roof and,typically, gutters and downspouts.Most homes and businesses alsohave landscape materials andirrigation systems placed aroundthe structures. The cisterns or

A Rainwater Harvesting System | 25

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LEFT:Leaf Eater downspout filter(or rainhead) mounted in thetraditional way at the gutter.RIGHT:Leaf Eater downspoutfilter (or rainhead) midmounted on wallSA

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storage tanks represent thelargest investment in a rainwaterharvesting system because mosthomes and businesses are notinitially fitted with a storage sys-tem. Storage cisterns can bedivided into three classes:

• Surface, at-grade or above-ground cisterns

• Below-grade, underground(including partially under-ground) tanks

• Integral cisterns or tanks builtinto a dwelling or commercialbuilding

Most cisterns and tanks havethree distinct components, allof which need to be waterproof:

26 | Design for Water

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LEFT:Small cistern next torooftop catchmentwith no first-flush

RIGHT:Metal cistern attached

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Cisterns of varioussizes and colors

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the base, the sides, and the cover.They also contain several minorcomponents as shown in Details2.1 and 2.2: water inlet, wateroutlet, access hatch, and meansof draining. A typical storagecistern is covered and made ofstone, steel, concrete, ferro-cement,plastic, or fiberglass. A storagesystem should be durable, attrac-tive, watertight, clean, smoothinside, sealed with a non-toxicjoint sealant, easy to operate,and able to withstand the forcesof standing water. A tight coveris essential to prevent evapora-tion and mosquito breeding, andto keep insects, birds, lizards,frogs, and rodents from enteringthe tank. Cisterns and tanksshould not allow sunlight toenter or algae will grow insidethe container.

Some storage tanks contain

settling compartments thatencourage any roof or pavementrunoff contaminants to settlerather than remain suspended.Storage tanks can have an inletfrom a sand filter or directlyfrom the gutters through a leafand debris filter. They must alsohave an overflow equal in size tothe inlet volume and an outlet ordrain. The overflow should day-light to a landscape basin or anadjacent drainage system.

The outlet leads to the dis-tribution system. Some systems,especially if they are a solesource of water or if landscapeirrigation requires supplementalwater, may have an inlet pipefrom an alternate, make-upwater source such as a municipalwater supply. Whenever an alter-nate, make-up water source isused with a storage system, an

A Rainwater Harvesting System | 27

White tanks, usually placedin dark locations toeliminate exposure to light

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LEFT:Corrugated metal pipe cis-terns, 5 feet in diameter by10 feet in height, 1,468 gal-lons eachRIGHT:Larger cistern holding 7,000gallons of rainwaterH

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air gap must be maintainedbetween the high water line orhighest flood line in the storagecistern/tank and the inlet of thealternate water. A typical air gapis 14 inches. The overflow lineshould be placed to maintainthe maximum high water line inthe cistern/tank. An additionalsecurity to avoid contaminationof the alternate water supply is abackflow valve, which should beinstalled in the alternate waterline prior to the water reachingthe storage container.

The type of storage systemchosen by a prospective rainwaterharvester depends on several tech-nical and economic considerations:

• Options available locally

• Space available

• Storage quantity desired

• Cost of the vessel

• Cost of excavation and soilcomposition (sand, clay, loam,or rock)

• Aesthetics (possibility of inte-grating cistern into thebuilding)

Answers to the above consid-erations will help to determineif an above-ground cistern orbelow-grade tank will be used.The above-ground storage sys-tem can be easily purchased offthe shelf in most communities,allowing for easy inspection andgravity water extraction/drain-ing. The above-ground storagesystems require space, can be

more expensive, and are suscep-tible to damage from constantexposure to the elements. Below-grade storage systems generallyare reasonably priced, requirelittle or no above-ground space,are unobtrusive, and permitthinner cistern walls due to thesupport of the surroundingground. Extracting water frombelow-grade systems is moredifficult—often requiring apump—and leaks and failuresare more difficult to detect. Inaddition, tree roots or overheadtraffic may damage the below-grade storage system.

Water in a storage cistern willtypically consist of three layers.19

The top layer, the aerobic zone,will be fully aged water; the mid-dle layer will be ageing water;and the bottom layer, the anaer-obic zone, will be a mixing waterthat contains the most solids. Totake advantage of this stratifica-tion, especially for potablesystems, a floating pump intakethat avoids the surface film wherefloating particles may be presentwould best allow the use of thefully aged storage cistern water.

The best system would havetwo intakes, one floating intakefor potable uses and one station-ary intake lower in the tank toallow the mixing water to beused for nonpotable uses. Thebest overflow would be onethat would allow water to exitfrom the anaerobic zone in thetank. Even better would be an

28 | Design for Water

German product display: sec-tion removed from a cisternto show a floating intake

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German product display:cistern side cut away to showan inlet flow calming device

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overflow that would vacuum orsuction out the sludge that mayaccumulate in the bottom of atank or cistern.

A cistern that is cool anddevoid of sunlight allows waterquality to increase with time.When photosynthesis cannottake place, most organisms dieoff as their food source is elimi-nated. With each rain event anew supply of sediment andorganisms will enter the storageunit. The sediment, while notusually unhealthy, can initiallydiscolor and flavor the water, butwill ultimately settle to the bot-tom of the storage container. Itis best to remove water from acistern or tank at a position thatis farthest from a runoff inlet toallow the water time to agebefore it is used. Some storagecontainers may require baffles,inflow smoothing filters, orturbulent dissipaters to slowthe inlet turbulence that remixesthe ageing water. In cisterns thatare open to the air and allowmosquito growth, a Bacillusthuringienis-israelensis (Bt-i)Mosquito Dunk disk can be usedto eliminate mosquito growth.

Proper foundations are veryimportant for all types ofcisterns: water is very heavy (a500-gallon tank full of water willweigh more than two tons)20 andsoil settling may occur and dam-age a tank. Manholes or accesshatches should be included inburied cisterns for cleaning and

inspection. Some systems mayhave a back-up cistern or tank.While this is an additional cost,it permits servicing of one unitwithout losing the operation ofthe entire system. Storage systemsshould be located to maximizeefficiency of both supply anddemand points as well as to usegravity where possible.

DistributionStored rainwater may be con-veyed or distributed by gravityor by pumping. If a tank islocated uphill or above the areaproposed for irrigation, gravitymay work. Most plumbing fix-tures, appliances, and dripirrigation systems require at least20 pounds per square inch (psi)for proper operation. Standardmunicipal water supply pres-sures are typically in the 40 psito 80 psi range.21 As a generalrule, water gains 1.0 pound persquare inch of pressure for every2.31 feet of rise or lift. Pumps,rather than elevated tanks, aretypically used to extract bothbelow-grade and at-grade cistern-or tank-stored water. Submersibleor at-grade pumps may be usedin any rainwater storage system.Self-priming pumps with float-ing filter intakes and automaticshutoffs—for times when waterlevels are insufficient—are opti-mal equipment. As mentionedpreviously, the bottom few inchesof stored water will typically con-tain very fine settled sediment

A Rainwater Harvesting System | 29

Bacillus thuringienis-israelensis (Bt-i)Mosquito Dunk

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Metal tankbase ring

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and should be avoided if possi-ble. Depending on the proximityof the rainwater inlet and pumpintake, as well as the time rain-water is left to settle or calm,the pumping process may needto be delayed for a short dura-tion after a rain event.

The storage system overflowmay act as a distribution systemthat delivers excess water to anadjacent landscape. All overflowsexposed or outletting aboveground should have some meansof stopping rodents and insectsfrom entering the storage sys-tem. Fine screens may be placedover the end of pipes and, inareas of high rain quantities,water traps—similar to sinksand toilets—may be used.

For landscape irrigation,stored rainwater may go throughadditional filters before it isdirected into an irrigation pumpand distribution lines. This maybe necessary to avoid cloggingthe irrigation system. For apotable water system, the watermust go through a purificationprocess prior to distribution.

PurificationIf harvested rainwater is to beused for potable supplies, therainwater would be pumpedfrom the cistern to the purifica-tion system and then distributedto the points of use such as akitchen sink faucet. In a non-potable system no purificationprocess is required. Potablewater treatment systems normal-ly include filters, disinfection,and buffering for pH control.Filtration can include any of thefollowing: in-line or multi-car-tridge, activated charcoal, reverseosmosis, nano-filtration, mixedmedia, or slow sand. Disinfectingcan include boiling or distilling,chemical treatments, ultravioletlights, and/or ozonization.Rainwater intended for humanconsumption should undergoseveral steps, including screen-ing, settling, filtering, anddisinfecting. Filtering and disin-fecting are two components ofrainwater harvesting that willenhance a potable system.

When water is being usedfrom storage, sediment filtrationshould be a maximum of 5-micron, followed by a 0.5-microncarbon filter or an equivalent1-micron absolute filter. Theseultra filters should be approvedby the National SanitationFoundation for cyst removal.These filters will removeGiaradia and Cryptosporidiumfrom the water supply. The ultra-violet disinfections are perfect

30 | Design for Water

Submersible pump andfloating filter intake

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LEFT:100mm Vented Flap Valve and

/or tank overflow outletRIGHT:

The 50mm Flap Valve incorpo-rates a non-corrosive plasticscreen of 0.955mm and the

100mm Flap Valve utilizes a rust-proof stainless steel screen of

0.955mm; both are vermin-proof

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for this application, although theNational Sanitation Foundationhas not approved them for thispurpose. If a 1-micron absolutefilter is used, then a carbon filtershould be installed to improvetaste and odor. Most filters havebeen designed to be used with

municipal supplies and do nothave a convenient method ofmonitoring when they havebecome overloaded and are duefor replacement. Filters connect-ed to a cistern system should bechanged more frequently thansuggested by the manufacturer.

A Rainwater Harvesting System | 31

ABOVE LEFT:Multisiphon overflowunit with floating ball toeliminate backflow of fluidsand smells and the stainlesssteel grill prevents rodentsfrom entering the tankABOVE RIGHT:Residential pressure tankssupply pumped rainwaterfrom the cistern to clotheswashing machine and toilets

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Rainwater filtrationsystemSH

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Solar water distillationsystems are extremely energyefficient and are one of thesimplest water purification sys-tems available. The solar systemspurify water using only the sun’senergy. No filters or membranesare required, no moving partsare used, and no electricity isneeded to run the solar distilla-tion system. Solar waterdistillation systems consist ofa shallow pan with a slopingglass cover. Rainwater to bepurified by a solar system isdirected to the pan where it isheated by the sun. The rainwaterevaporates from the pan, rises,condenses on the undersideof the glass cover, and runsdown into a collection trough.From the trough the purifiedrainwater flows to a clean con-tainer for storage. Theundesirable contaminants leftbehind in the pan are flushedfrom the pan daily. Solar distilla-tion panels can be mounted onroofs or on ground structures.22

Rainwater quality is gener-ally acceptable for potable useexcept when contaminated byorganics such as leaves.Chemicals may be used to steril-ize and purify the stored water.Rainwater used for potable sys-tems should be periodicallytested for quality and content.The quality of rainwatergathered for nonpotable uses,typically judged on the size ofsuspended solids, can be much

lower. Nonpotable water needsto be devoid of suspended solidsthat may be too large to passthrough the distribution system.With a drip irrigation system,additional filters can be used toavoid clogging the emitters.

Regular maintenance of allrainwater harvesting systemcomponents is required toprovide optimal collection ofrainwater. First-flush devicesshould be emptied after eachstorm, gutters should be cleanand free of debris, and overflowlines should be free of obstaclesthat may block the pipe. Filters,pumps, and the cistern or stor-age container must be checkedperiodically to identify any lossof efficiency and to flush anydebris that may have collected atthe bottom. All piping and con-nections should be periodicallyinspected and repaired, ifneeded. All landscape channels,berms, and basins should becleaned of nonorganic debris.Signs of erosion should beevaluated so that runoff can bestopped or redirected in orderto increase percolation time. Inaddition, landscape irrigationemitters and plant basins shouldbe expanded as plants and theirroots grow.

System ComplexityThe concept of rainwater har-vesting has been explained, butbefore an actual system can bedesigned, several basic questions

32 | Design for Water

Left to right are 3 filters:a 5-micron sediment filter,a 0.5 micron carbon filter,

and UV purification

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Page 52: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

must be answered and decisionsreached regarding the system’ssize, complexity, cost, andintensity of use and purpose.Rainwater harvesting systemscan be designed for small orlarge projects. They can retrofitan existing site or be an integralcomponent of a new project.Designing a rainwater harvestingsystem for a new project hasadvantages, in both ease andcost, over retrofitting an existingbuilding or site. A rainwaterharvesting system can bedesigned as a passive, low-costsystem or as an active, morecomplex and costly system. Adecision needs to be made as tothe intensity of use of a systemand the intended use of thewater, i.e., for nonpotable and/orfor potable water.

The intended water demandsmust be evaluated through awater budget. During a rainyseason the demand for water maybe low, but during a dry season,

a high demand may be placedon the rainwater harvestingsystem. The quantity of waterrequired during the dry periodsor high demand times will deter-mine the quantity of rainwatercollected during rainy periods,which in turn will determine thecistern’s storage capacity.

Storage capacity is one wayto classify a rainwater harvestingsystem. A small system wouldhave a storage capacity of 1,000 to5,000 gallons, a medium system5,001 to 10,000 gallons, a largesystem 10,001 to 25,000 gallons,with a very large system rangingup to 100,000 or 200,000 gallonsand more. When determining thecapacity needed, one should keepin mind the following atypical sit-uations. In an area where uniformrainfall continually replenishessupplies, a rainwater harvestingsystem may have a small storagecapacity and still be able to sup-port high daily demand. However,in an area with long periods

A Rainwater Harvesting System | 33

LEFT:A residential solar waterdistillation systemRIGHT:Passive rainwater harvesting:landscape swale directswater from street gutter intolandscaped areaC

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between rainfall, a rainwaterharvesting system may need avery large storage capacitydespite a low daily demand forwater. The time period betweenrainfall events and number oftimes a user must rely on a rain-water harvesting system isknown as the intensity of use ofthat system. Rainwater harvest-

ing systems can be additionallyclassified for intensity of use bythe amount of water security orreliability provided by the sys-tem. Four levels of commitmentto rainwater harvesting havebeen identified: 23, 24

1. Occasional: this is typically asmall storage capacity system

34 | Design for Water

Passive rainwater harvesting:landscape basin with low

walls to slow runoff

Passive rainwater harvesting:butterfly roof drains to a cis-

tern next to a garden

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that collects rainwater forone or two days of use.During a rainy period userswill have the benefit of havingmost of their water needs,possibly all of their needs, metby the stored rainwater. Analternative water source wouldbe required for dry weather.This system is best for climates

with a uniform rainfall pat-tern and very few dry daysbetween rainfall events.

2. Intermittent: this is typicallya small- to medium-storagecapacity system where theuser’s needs are met for aportion of the year. Dryperiods may require an

A Rainwater Harvesting System | 35

Lowe’s Home ImprovementCenter that has four18,100 gallon tanksJA

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Fort Worth BotanicalGardens which has a5,000-gallon TimberTankfor irrigation of plants

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alternate water source. Thissystem is best for climateswith a single rainy season,where it can meet most orall of a user’s needs duringthat part of the year.

3. Partial: this is typically amedium- to large-storagecapacity system. It providessome of the water neededfor a landscape or all of thehigh-quality water needs,such as drinking water, forthe user during the entireyear. An alternative watersource is needed to providewater for the remaining por-tion of the water needs for atleast the historic dry season.This system is best in areaswhere a dependable, uniformrainfall occurs in a single ortwo short wet seasons.

4. Full: This is typically a largestorage capacity system thatprovides all of the waterneeded by the user for thewhole year. This may be thebest option for areas with noalternate water source. Itrequires strict monitoringand regulated use of thewater supply.

All factors classifying a rain-water harvesting system, includingwater supply demand, storagecapacity, and intensity of use,can be determined and evaluatedwith the creation of a waterbudget, or water balance analysis.

Water BudgetA water balance analysis, typical-ly referred to as a water budget,describes the amount of rainwa-ter that can be collected in theproject catchment area anddetermines if that amount willmeet the user’s water demands.A water budget will provide asupply-and-demand analysis ona monthly basis and will helpdetermine the size of the storagearea. In addition, a water budgetwill determine how much, if any,supplemental water is needed toaugment the intended use of thecollected rainwater.

The same budget steps can becompleted for any specified waterdemand whether it is potable ornonpotable. If the water require-ments are determined to belarger than the rainwater system

36 | Design for Water

Passive rainwater harvesting:stepped walls to slow

down runoff

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is able to provide, and supple-mental water is not wanted orcannot be used, the water budgetwill help determine how muchthe demand must be reduced tomatch the rainwater supplied.Redesigning a project to increasethe catchment area, if possible,may be an option to increase thequantity of rainwater captured.An optional supplemental watersupply, such as a well or munici-pal water, can serve as a securitysystem for years of low rainfallor if a system needs servicingand the cistern requires drain-ing. Because a water budget isbased on average annual rainfallit will not be exact or guaran-teed, but it should be used as aplanning tool to help refineproject goals as well as refine thewater collection system and theintended water use.

A catchment area quantitiestable can be prepared on a gal-lons-per-month basis by usingthe average monthly rainfall forthe site. When the catchmentarea is restricted and cannot beexpanded, a conventional collec-tion formula may be used todetermine runoff quantities.The first step is to multiply thecatchment area in square feet bythe amount of rainfall received(expressed in feet). This quantityis then multiplied by the percentefficiency afforded by the col-lection surface and finallymultiplied by 7.48, which is thenumber of gallons in a cubic

foot. The result is the amountof rainwater collected from thecatchment area. This first for-mula needs to be completedfor each collection area andefficiency type, for each month.Catchment collection efficiencieshave been estimated by varioussources. Table 2.1 shows typicalrunoff efficiencies that have beenproven appropriate for the con-struction material listed.

When the individual col-lection area boundaries areundefined, or if the collectionareas are adjustable and/or thewater available is on a budget,Formula 1 must be reconfigured(see Formula 2) to determine thearea required for collection.When the required/allowed gal-lons of water per day are known,the first step is to multiply thegallons required per day by 365days a year for the total waterrequired per year for the project.The second step is to multiplythe annual rainfall in inches by0.623, which converts inches ofrain into gallons per square footof area (7.48 gallons per cubicfoot divided by 12 inches equals0.623). The third step is todivide the total gallons requiredper year by the gallons of rain-water collected per square footper year. The resulting numberis the catchment area in squarefeet required to collect, with100 percent efficiency, the quan-tity of water required by thewater budget.

A Rainwater Harvesting System | 37

Page 57: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

After the catchment areais determined, the conventionalformula can be completed todetermine runoff supply foruse in the water budget. Alarger catchment area may berequired to meet the waterdemand, depending on therunoff efficiencies of the catch-ment surface.

Table 2.2 shows an exampleof an available runoff supply fora typical 10-acre commercialproject in Phoenix, Arizonausing both rooftop and groundlevel catchment areas. Formula 1was used to complete this table,using catchment areas of 94,520square feet of roof area and257,967 square feet of pavementarea. The table can be expandedas appropriate for the numberof catchment areas proposed.Once the potential water runoffsupply is calculated, a tableshowing the water demand on amonthly basis and water supply(runoff) on a monthly basis canbe prepared.

Formula 1. Catchment arearunoff in gallons(CA) x (R) x (E) x (7.48) =Catchment area runoff in gallons

Where:CA = Catchment area (square feet)R = Rainfall (expressed in feet)E = Efficiency (See table 1)

Formula 2. Total catchmentarea required in square feet[(TWR) x (365)] divided by

[(AR) x (0.623)] = Total catch-ment area required in square feet

Where:TWR = Total waterrequired/allowed per day (gallons)AR = Annual rainfall (inches)

Water Balance AnalysisThis table, known as a waterbudget (Table 2.3), determines ifthe amount of rainwater collect-ed meets the quantity requiredby the demand proposed or ifsupplemental make-up waterfrom another source will beneeded. A designer can use themaximum gallons harvested andrecorded under the heading ofaccumulative storage, shown inthe water budget, to calculate thevolume and number of cisternsthat will be required for the pro-posed project.

The largest quantity shownin the water budget for the avail-able runoff supply will be themaximum gallons flowingthrough the storage system; how-ever, a portion of the rainwaterthat has entered into storage willexit after the rain event, as irri-gation in the Table 2.3 example.Therefore, the maximum accu-mulative gallons (or maximumstored gallons) shown in thewater budget will be the amountused to size the storage system.

Consider pipe spacing insidea cistern or tank from the topof the cistern when preparingstorage capacity calculations or

38 | Design for Water

Table 2.1

ESTIMATED RUNOFFEFFICIENCIES

90% Smooth, imperviousroof surfaces, i.e., metal, tile,built-up and asphalt shingle roof.

80% Gravel roof andpaved surfaces.

60% Treated soil.

30% Natural soil.

Estimated runoff efficiencies for urban surfaces

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when designing the inlet for asupplemental water supply. Acistern capacity should be calcu-lated from the floor of thecistern to the invert of the over-flow pipe. An overflow outletpipe invert is typically provided10 to 12 inches below the top ofa cistern or tank, which meansthe top 10 to 12 inches is air-space and should not becalculated as storage capacity.Additional height will berequired within the cistern forthe inlet from downspouts and ifan alternate make-up watersource is proposed (Details 2.1and 2.2). Some cisterns are basedon gallons of capacity and othersare based on cubic feet of stor-age. To determine the cubic footcapacity of a required cistern,Formula 3 can be used to changegallons to cubic feet of storagerequired. Formulas 4 and 5 canbe used for sizing square andround cisterns and providingcubic feet of storage estimates.

A typical monthly landscapeirrigation requirement for a typ-ical 10-acre commercial projectin Phoenix, Arizona was usedto complete the water budgetshown in Table 2.3. As the tabledemonstrates, if all the rooftopand pavement areas were used toharvest rainwater, an excess ofrainwater would be collected.Thus, the water budget wouldnot balance. Removing rooftopor pavement areas from thecatchment quantities will reduce

the maximum accumulativestorage of 443,431 gallons.Alternatively, the landscape areascould be increased to accommo-date the use of more rainwater.To ensure a balanced budget forthe typical project, a decisionwould need to be made to eitherincrease the landscape areas orreduce the catchment size.

The water budget shown is foran established landscape. Newlyplanted vegetation will requiresupplemental water in addition tothe harvested rainwater/storm-water during the plantestablishment period. The plant

A Rainwater Harvesting System | 39

Table 2.2

POTENTIAL RUNOFF SUPPLYRooftop Pavement

Phoenix collection at collection atrainfall 90% efficiency 80% efficiency

Month in feet in gallons in gallons Total

January 0.063 40,087 97,252 137,339

February 0.061 38,815 94,164 132,979

March 0.061 38,815 94,164 132,979

April 0.028 17,817 43,223 61,040

May 0.011 6,999 16,980 23,979

June 0.008 5,091 12,349 17,440

July 0.078 49,632 120,407 170,039

August 0.085 54,086 131,212 185,298

September 0.066 41,996 101,883 143,879

October 0.043 27,361 66,378 93,739

November 0.053 33,724 81,815 115,539

December 0.074 47,087 114,232 161,319

Annual 0.631 401,510 974,059 1,375,569

Potential runoff supply for each catchment area

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establishment period would typ-ically be two to five years, afterwhich supplemental water wouldnot be needed. The excess rain-water listed in the water budgetcould be used during the plantestablishment period; once theplants are established, the catch-ment areas could be reduced toprovide a balanced water budget.

The excess rainwater could alsobe allowed to recharge theaquifer by infiltrating throughoverflow outlet pipes to a land-scape basin or a drywell.

Storage of the collected rain-water could be in above-groundor below-grade cisterns. Thebelow-grade storage would beappropriate due to the valuable

40 | Design for Water

Table 2.3

TOTAL LANDSCAPERunoff

Irrigation minus Excess Irrigation Irrigationrequirement Available landscape runoff requirement fromfor established runoff irrigation to storage Accumulative from municipal

plants supply requirement requirement storage storage supply

January 41,748 137,339 95,591 95,591 329,377 0

February 58,076 132,979 74,903 74,903 404,280 0

March 93,828 132,979 39,151 39,151 443,431 0

April 131,867 61,040 -70,827 372,604 70,827 0

May 162,460 23,979 -138,481 234,123 138,481 0

June 179,897 17,440 -162,457 71,666 162,457 0

July 172,746 170,039 -2,707 68,959 2,707 0

August 153,744 185,298 31,554 31,544 31,554 0

September 126,407 143,879 17,472 17,472 49,026 0

October 93,828 93,739 -89 48,937 89 0

November 54,595 115,539 60,944 60,944 109,881 0

December 37,414 161,319 123,905 123,905 233,786 0

Total AnnualGallons 1,306,610 1,375,569 68,959 443,520 443,431 374,561 0

Water budgetCalculations were completed for the selected 10-acre commercial project in Phoenix.

Note: The above rainwater harvesting process was started in August with the summer rains in order to accumulate enough rainwater to fulfill the next sum-mer’s irrigation needs. The August quantity of 31,554 gallons begins the water budget/accumulative storage process. Each month as rainwater is harvestedthe quantity increases; during months that require water for irrigation above what is harvested for that month, the deficit is subtracted from the accumula-tive storage quantity. The accumulative storage is a running total of water in the cistern. The maximum amount of rainwater stored, 443,431 gallons,occurs in March. A cistern or storage facility is sized to hold the maximum accumulative quantity of rainwater plus a little extra as a safety factor or bufferfor a non-average rainfall year.

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land needed to provide buildingsand parking spaces and due tothe large size of the maximumaccumulated storage quantity.

The water budget for theselected typical 10-acre commer-cial project demonstrates howvaluable a water budget can bein the planning phase of a proj-ect. It allows several options tobe evaluated prior to selectingan appropriate ratio of catch-ment size or runoff quantity towater requirement.

Water BudgetFormula 3. Determining cubicfeet of water(Accumulative storage in gallons)divided by (7.48 gallons percubic foot) = Cubic feet of stor-age required

Example:(5,000 gallons accumulativestorage) divided by (7.48 gallonsper cubic foot) = 668 cubic feetof storage

Formula 4. Sizing square orrectangular cisterns(Length) x (Width) x (Max.height of stored water) = Cubicfeet of storage provided

Example:10 feet long times 9 feet widetimes 10 feet high = 900 cubicfeet of storage provided

Formula 5. Sizing round cisterns(TTr 2) x (Max. height of storedwater) = Cubic feet of storage

Where:TT = 3.14r2 = Radius of cistern squared

Example:3.14 times 5-foot radius squaredtimes 10-foot height = 785 cubicfeet available for storage

Cold Weather ConsiderationsWinter hydrologic conditions—ice, freezing temperatures, snow,and snowmelt—present specialconsiderations for water collec-tion and stormwater runoff.With freshly fallen snow, 10inches of snow equals approxi-mately 0.7 inches of water;another way to calculate it is that14 inches of snow equals 1 inchof water. Over time, the snowbecomes more compacted andby the time it begins to melt itwill yield more water per inch.In this case, 3 to 4 inches ofsnow will equal 1 inch of water.

The list below addresses afew of the considerationsrequired for cold climates.

Tanks: Larger tanks are rec-ommended as a large tank willtake longer to freeze than a smallone; a round tank is recom-mended as a round tank will loseheat more slowly than a rectan-gular one of the same volume;straight sides are recommendedas corrugated sides have moresurface area; insulation is recom-mended, e.g., spray-onpolyurethane foam; tank roofsshould be designed to withstandheavier loads such as snow and a

A Rainwater Harvesting System | 41

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steep-angle roof allows the snowto slide off faster; a central tankroof support is recommendedfor additional strength; tanksshould be designed to take intoaccount the rising and fallingwater surface level and internalfittings—ladders attached towalls—should be avoided.25

TankWater: In cold watersettling velocities are up to 50percent slower; 26 higher pollu-tant levels maybe experiencedin the water as the pollutants—such as ash from fireplaceuse—will likely build up duringthe cold season and when meltdoes occur, larger quantities ofrunoff water may be experi-enced; 27 during deep-freezeconditions moving water is lesslikely to freeze than standingwater and the water in thetank may need to be constantly

cycled to prevent freezing, possi-bly cycled through a solar hotwater system.28

Pipes: If possible pipesshould be buried below thefreeze line; pipe distributionpoints should be located as closeto the use as possible and prefer-ably inside a building; usingsuitable piping materials willreduce the probability of pipessplitting; Medium DensityPolyethylene (MDPE) remainsductile even at lower tempera-tures (health implications ofdrinking water filtration require-ments is unknown and waterquality should be evaluated withall piping materials), and thetypical warm-weather PVC pipeis more brittle at lower tempera-tures; if the system is not usedduring cold periods, the pipesshould be drained.29

42 | Design for Water

Wooden tank constructionin cold climate – base

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Valves: Valves can be pro-tected by being placed ininsulated boxes.30

Tank Foundations: Heatloss from the water in thetank to the ground may occurcausing the soil below the waterto thaw quicker causing struc-tural instability; mounting atank on an insulated concrete

or gravel base will reduce theheat transfer.31

Pumps: The fact that enginefluids thicken at lower tempera-tures should be taken intoaccount and appropriate dieselsand oils should be used; pumpsshould be protected in a pumphouse or insulated box.32

Chlorination: The reaction

A Rainwater Harvesting System | 43

Wooden tank constructionin cold climate – sidesSH

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rate of chlorination is seriouslyaffected at lower temperatures,if this is a technique used forpurification, more time may berequired for the purification/reaction time.33

Cold climates cause moreconcern for maintenance as thetank, pipes, valves, and othercomponents of a system such

as the roof of an above-grade tankneed to be inspected more oftento evaluate conditions andpotential stress points. This listis a beginning and some itemsmay have been overlooked asevery site is unique and may havespecial issues to be evaluated.

The Alaskan BuildingResearch Series HCM-01557,

44 | Design for Water

Tank in thehigh mountains JA

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Tank located at 9,000 feetelevation near Aspen,Colorado, in the snow

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A Rainwater Harvesting System | 45

Left: top to bottom:- Cistern built partially above ground.- Frost protection using the soil geothermal heat (in nonper-mafrost areas only).

- Frost protection of cistern on rock.

Right: top to bottom:- If excavation to frost free depth is extreme, the groundabove the cistern can be insulated with blueboard or similar.

- Frost protection can consist of pipe insulation and heat tapewithin pipes and the cistern.

- Frost protection of cistern with heat tape, note temperaturesensor is placed inside the cistern.

Cold weather details

(Source: Water Cistern Construction for Small Houses, Alaska Building Research Series HCM-01557)

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46 | Design for Water

Water Cistern Construction forSmall Houses, lists a few goodpoints to be addressed whenusing cisterns in cold climates.Those points are as follows:

• In nonpermafrost areas anabove-grade cistern may onlyneed side and top insulation,as soil heat may be enough tokeep the water from freezing.

• If a cistern is placed on solidrock, soil warming of thecistern water is unlikely andthe cistern bottom should beinsulated.

• Insulation of square or rectan-gular cisterns should useboards of extruded poly-styrene due to theirmoisture-resistant properties.Cylindrical cisterns should beinsulated with batt insulationand a Visqueen (polyethylene)outer layer.

• If a cistern is located below-grade it needs to be placedbelow the freeze depth toavoid frost/freeze problems.If this is an extreme depth, anoption would be to insulatethe ground above the cistern.

The necessary depth of soilcover will relate to the thick-ness of the insulation.

• All pipes should be insulatedand heat tape threaded insidethe pipes or wrapped aroundthem. Heat tapes can be placedin loops on the bottom of thecistern as well as around theintake. An automatic thermo-stat with a temperature sensorplaced inside the cisternshould be used to turn theheat tapes on and off.

• Heat tapes can be used ondownspouts, gutters, andalong the roof eaves to avoidfrozen systems and allowwater collection to be contin-ued during cold times. Thestorage system can also bedisconnected from the collec-tion components during thewinter if no collection isneeded or desired.

• Summer cisterns shouldalways be emptied, cleaned,and decommissioned(including disconnectingdownspouts) for the winterseason.

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THIS CHAPTER describes pas-sive rainwater and

stormwater catchment tech-niques and components. Passiverainwater collection, using suchtechniques as site grading andpermeable surfaces, diverts andretains stormwater so that itbenefits the landscaped elementsof a site. Details provided in thischapter are meant to be startingpoints for a passive system;individual systems and compo-nents should be customized forspecific sites. Active rainwatercollection, described in previouschapters, not only diverts thestormwater, but also stores it forlater use. It makes use of suchfeatures as architectural ameni-ties, first-flush diverters, andstorage systems. Details foractive systems are provided inChapter Four.

A More Natural ApproachUsing proper techniques, bothon-site runoff and off-site flowscan be caught using passivemeans. Planning for this type

of water catchment requires anintegrated design process whereall team members—includingthe owner, planner, developer,engineer, architect, landscapearchitect, contractor, and main-tenance personnel—worktogether to attain an effectivecollection system. The followingpages describe and illustrate var-ious techniques that can be used.

Passive water collectionstarts by managing stormwater atthe top of the watershed. A proj-ect might have multiple microwatersheds within its boundaries,all of which can assist in slowing

Don’t empty thewater jar until therain falls.

— Philippine proverb

Landscape swaleafter a spring rain

Passive Rainwater andStormwater Catchment

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and spreading the stormwater.Proper site grading can makemaximum use of watersheds.Stormwater will erode less soil and

percolate more when its velocityis reduced and it is spread outover a permeable surface.

There are numerous waysto slow and direct stormwater,including microbasins, swales,French drains, rain gardens,permeable pavements, and curband road grading design. To pre-vent the possible destabilizationof sloped areas, it is best to con-sult an engineer if any of thesetechniques are used on or adja-cent to slopes over 10 percent.

A more natural approach toland development is needed tomimic natural cycles, especiallythe hydrological cycle. In anundisturbed environment almostall rain and snowmelt soak intothe ground where it falls and onlythe heavier rains exceed infiltrationrates to produce surface runoff.The gentle sustained infiltrationsupports plant life, maximizesgroundwater recharge, and mini-mizes flooding and erosion.

Collecting and storing waterin the soil, above the water table,is a process that increases“green” water levels. Increasingsoil moisture means less waterneeds to be artificially applied toa landscape to maintain its exis-tence. In an urban setting muchof the land surface is coveredwith impervious surfaces, sur-faces that disconnect the naturalhydrologic cycle. These imper-meable surfaces increase runoffvelocities, therefore increasingerosion and flooding hazards.

48 | Design for Water

Passive rainwater harvesting:landscape retention basin

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Passive rainwater harvesting: curb cutallows rainwater from street gutter toenter landscaped/natural desert area

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Passive rainwater harvesting:curb cut allows surface flow

to enter landscape basin

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There are several existingexamples of this more naturalapproach, including a techniquealso known as Low ImpactDevelopment, or LID. The mostwell known example is the 1999manual prepared by PrinceGeorges County, Maryland,Department of EnvironmentalResources entitled Low ImpactDevelopment Design Strategies:An Integrated Design Approach.More can be found on this topicat the Low Impact DevelopmentCenter website www.lowimpactdevelopment.org.

The City of Portland is onemunicipality that has made acommitment to provide a morenatural approach to stormwatermanagement. An example oftheir commitment is demon-strated in their Green Streetsprogram. This program converts

previously underutilized land-scape areas adjacent to streets intoa series of landscaped storm-water planters that are designedto accept street runoff, slow it,cleanse it, and infiltrate it.Excessive runoff exits one planter,only to enter the next. Eventually,if the quantity of stormwaterentering the basins exceeds thesoil’s holding capacity, the

Passive Rainwater and Stormwater Catchment | 49

Passive rainwater harvesting:permeable pavement(pavers) used to identifyparking spaces

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LEFT:Passive rainwater harvesting:permeable pavement (pavers)RIGHT:Passive rainwater harvesting:drain at base of steps leads toadjacent landscaped area

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stormwater is allowed to enterstorm drains, but at a muchdelayed rate and in a muchcleaner state.

This retrofit of street curbsand landscape planters managewhat were typically direct flowsof street runoff to storm drainsthat originally fed directly intothe Willamette River. The Cityof Portland EnvironmentalServices has prepared a manual

dated November 2003 titled:Sustainable Site Development,Stormwater Practices For New,Redevelopment, and Infill Projects.This manual lists eight actions,benefits of each action, and jus-tification for each action. Listedbelow are the eight actions:

1. Manage stormwater as closeto the source as possible toreduce or eliminate the vol-ume of water and pollutantsleaving the site. Integratestormwater into site devel-opment, building, andlandscape design.

2. Preserve, protect, andplant trees and vegetation.Increase use of native treesand vegetation.

3. Reduce impacts from imper-vious surfaces such as streets,parking lots, rooftops, and

50 | Design for Water

Passive rainwater harvesting:landscape basin

for runoff infiltration

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Green Streets Project:signage

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other paved surfaces.

4. Avoid disruption alongstream corridors. Createvegetative buffers.

5. Avoid development in thefloodplain and restore natu-ral floodplain functions.

6. Prevent and control erosioncaused by construction and

routine site developmentactivities such as clearingand grading.

7. Locate and design streets toprotect stream corridors andreduce high flows and pol-luted runoff.

8. Educate and enlist localagencies and the community

Passive Rainwater and Stormwater Catchment | 51

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LEFT:Green Streets Project:view looking uphillRIGHT:Green Streets Project:view looking downhill

Green Streets Project: inletwith asphalt diversion dam

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in these guiding principlesand actions.

Details for Passive CollectionThere are numerous ways tocapture and maintain stormwa-ter on a site. Rooftop water canbe captured and stored forfuture irrigation use or for non-landscape uses, which will

eliminate the captured waterquantity from runoff calcula-tions allowing only surfacerunoff to be dealt with throughpassive approaches.

Microbasins are small catch-ment areas that are best forlow volumes of stormwater. Byslowing stormwater, they allowinfiltration rates to increase.

52 | Design for Water

Passive rainwater harvesting:permeable parking lot

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Green Streets Project:end with stormdrain H

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They can be located in a line orin an alternating pattern thatallows overflow to be repeatedlyslowed to allow additional infil-tration. The microbasins can betree wells, planter islands—withcurb cuts allowing stormwater toenter similar to the Green StreetsProgram—or just small depres-sions next to a path or drive.

Swales are gently slopingtrenches meant to slow sheetflow and to allow longer stand-ing/infiltration periods. They arebest for low to medium volumesof stormwater. Swales can belocated next to sidewalks, paths,and driveways—typically theydirect stormwater towards vege-tation and away from buildings.

Passive Rainwater and Stormwater Catchment | 53

Passive rainwater harvesting:permeable parkinglot drivewayH

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University of Arizona, Tucson,Arizona stepped stormwaterbasins adjacent to abuilding, note gutter down-spouts feed each basin

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They can vary greatly in widthand treatment, from small shortdepressions to long trenchesgraded across a site requiring theuse of heavy equipment. Swalesare typically graded with thecontours or perpendicular to theflowing water.

French drains and raingardens are designed to absorbstormwater rapidly from the sur-face. French drains and pumicewicks are rock-filled excavationsthat lead to below-grade storageor infiltration areas. They canbe dug vertically or horizontallyin the earth, and they may bereferred to as soak-a-ways ordrywells. Rain gardens are land-scaped areas that are designed todirect stormwater to a centralstorage or infiltration area.

Permeable pavement canalso be used to slow stormwaterand allow more infiltration to

occur. Streets, patios, sidewalks,crosswalks, and parking lots canconsist of pavers that allowstormwater to pass betweenthem to sand or gravel sub-baselayers that lead to a natural soilsub-base material.

Finally, passive rainwaterand stormwater collection tech-niques can include the gradingof a site to allow stormwater topass over or through curbs toenter depressed, and typicallylandscaped, planter islands inparking lots or adjacent land-scaped tracts. Sidewalks anddriveways can be graded towardsa landscaped area instead oftowards a storm drain. Theselandscaped islands and tractscan be designed as individualrain gardens or just as a typicallandscape area. Either way theadditional stormwater runoff willbenefit the existing vegetation.

54 | Design for Water

Additional passive rainwaterharvesting: sidewalk drain

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Passive rainwater harvesting:sidewalk drain H

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Passive Rainwater and Stormwater Catchment | 55

Passive rainwater harvesting:green roof on a libraryin Salt Lake, UTH

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Passive rainwater harvesting:green roof on churchin Salt Lake, UT

Passive rainwater harvesting:drainage swale nextto sidewalk

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56 | Design for Water

Passive rainwater harvesting:infiltration cells next to trees

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Microbasins

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Passive Rainwater and Stormwater Catchment | 57

Stepped stormwater basinsmanage overflow fromother basins fedfrom downspout drainsH

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Swales

Passive rainwater harvesting:rock weir on a swale

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58 | Design for Water

French drains

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Passive rainwater harvesting:gutters extend from the

building to drop rainwaterinto a permeable channel for

infiltration and irrigationof adjacent vegetation

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Passive Rainwater and Stormwater Catchment | 59

Passive rainwater harvesting:permeable channel belowthe extended guttersH

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Depressed parking lotlandscape island

Passive rainwater harvesting:infiltration cells with weirs

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60 | Design for Water

Sidewalk grading

LEFT:Passive rainwater harvesting:

entry driveway curbs areflush with asphalt to allowrunoff to enter landscape

RIGHT:Passive rainwater harvesting:church parking lot median

without curb allows runoff toenter basin; basin is then

stepped to detain water untilit has had an extended timeto infiltrate the landscape

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Passive rainwater harvesting:parking lot basin accepts siterunoff and irrigates vegetation

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Passive Rainwater and Stormwater Catchment | 61

Roadway grading

Rain garden, plan view

Rain garden, section viewwith natural stone

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62 | Design for Water

Passive rainwater harvesting:rain garden with curb cuts to

allow round-about runoff waterinto the landscape for infiltra-

tion and passive irrigation

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Concrete Unit Pavers

Rain garden, sectionview with crates

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Passive Rainwater and Stormwater Catchment | 63

Passive rainwater harvesting:concrete unit pavers

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1 Keep microbasins and swalesfree of debris while maintainingsurface mulch. (Mulch reducesevaporation.)

2. Block and/or repair any erosiontrails that develop at overflowsand spillways.

3. As plants grow, expand basinsfeeding them to encourage wideroot development.

4. Augment active rainwater systemwith an alternate water sourceuntil plants are established, thenwean plants off irrigation water.

5. Fine-tune landscape contoursto control spillways, aesthetics,and functionality.

6. Inspect site before and aftereach rain event.

7. Keep mud and sediment out ofFrench drains and wick areas. Ifpossible, use with only roof-toprunoff or use vegetated swales orbasins to remove sediment priorto water entering French drains.

8. Inspect rain gardens for failureor unwanted erosion prior toand after each rain event.Maintain clear riser grates andstone trenches.

9. Sweep permeable pavers with astreet-sweeping machine everythree to five years; follow manu-facturer’s guidelines.

MAINTENANCE OF PASSIVE RAINWATER AND STORMWATER FEATURES

LEFT:Passive rainwater harvesting:curb cuts on commercialsite allow runoff to enterlandscaped areaRIGHT:Passive rainwater harvesting:curb cuts at entrydrive allow runoff toreturn to desert vegetation

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Page 84: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

THIS CHAPTER provides informa-tion on all the components

involved in an active watercatchment system. Each compo-nent is initially discussed ingeneral, then maintenance infor-mation is itemized, and details areprovided for better understandingof the individual components.

Rooftops, Gutters, andDownspoutsRooftops, gutters, and down-spouts can capture and direct

rainfall and protect buildingsfrom water damage. Gutters anddownspouts also transport rain-water away from sensitive areassuch as doors, walkways, andprotected soils. Gutters are typi-cally only used on residentialbuildings, but downspouts areused on both residential andcommercial buildings.

When buying metal gutters,choose the thickest metal avail-able and look for primary orvirgin materials. Secondary or

….Good luck andgood work for thehappy mountainraindrops, each one ofthem a high waterfallin itself, descendingfrom the cliffs andhollows of the cloudsto the cliffs and hollowsof the rocks, out ofthe sky – thunderinto the thunder ofthe falling rivers.

— John Muir

Butterfly roofon garage

Equipment for anActive RainwaterCatchment System

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recycled materials are ofteninconsistent in thickness and maycontain dissolvable non-potablesubstances. Thin materials maybe damaged or crushed byfalling branches or ladders thatare leaned up against them,though damage through mainte-nance can be avoided by carefuluse of ladders and other mainte-nance equipment. Vinyl orplastic gutters are susceptible todamage by maintenance equip-ment, but are impervious to rustand rot. Vinyl gutters can alsobecome brittle in extreme hotand cold climates. Steel andaluminum gutters are the mostcommon materials used in resi-dential systems. Galvanized steelgutters are the most economicalchoice and are stronger thanaluminum gutters, but theymay eventually rust. Stainlesssteel gutters, though they arethe most expensive, are thestrongest, remain rust-free, andmaintain a high sheen for years.

All gutter sections should beattached to downspouts via dropoutlets, and should have endcaps and corner pieces. Individualgutter sections can be connectedor joined with snap-in-placeconnectors. Joining two sectionsof gutter together always allowsa potential spot for leaks: theuse of seamless or continuousgutter will help to eliminatethis problem. Gutters come innumerous shapes, sizes, and col-ors. Downspouts are typicallyround or square and can matchthe gutter color.

Gutter covers and protectorsdefend the gutter from potentialclogging and sagging due todebris weight or standing watercaused by items that may enterthe gutter, such as plant materi-als, animals, or toys. They canbe found in numerous forms,including snap-on screens,grates, louvered (stepped orslotted filters), and helmet-like(which allow rainwater to enter

66 | Design for Water

LEFT:Blue Mountain Mesh all

steel gutter meshon corrugated roof

RIGHT:Red clay tile roof SA

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through a thin linear slotbetween gutter and cover).

There is a wide variety ofsuitable roofing material, but beaware that copper roofs are notsuggested for any type of collec-tion system. Galvanized roofs,which contain zinc, are likewisenot appropriate for potable col-lection systems.

MAINTENANCE OF ROOF GUTTERSAND DOWNSPOUTS

1. Conduct a visual inspection ofgutters and downspouts everysix months to ensure that all clipsand brackets are secure and notbroken. Any broken or missingcomponents should be repaired.Check slope of gutters to main-tain positive drainage.

Equipment for an Active Rainwater Catchment System | 67

Standing seammetal roofH

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Grey flattile roof

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2. At six-month intervals removeaccumulated debris and clogs.Where vegetation overhangs gut-ters, inspect them every threemonths for leaf accumulation,rust, and mold.

3. Inspect gutter system before andafter each rainy season.

4. Trim trees and vines away fromgutters to maintain a minimum24-inch clear zone.

5. When gutter covers are used,inspect to eliminate any openingsthat may allow birds or otheranimals to enter and build nests.Inspect all cover clips to ensurethe guards will not collapse andcause a blockage in the system.Inspect gutter cover for debrisaccumulation; dry accumulateddebris may become a fire hazardand must be eliminated.

6. Downspouts and outlets locatedin landscape areas should beinspected every six months toensure that splash pad placementis correct and that there is posi-

tive drainage away from the out-let and adjacent buildings; main-tain a minimum of 2 percentslope for the first 5 feet. Checkfor animal inhabitations andclogs. Check landscape growthevery two weeks during growingperiods to protect from over-growth, which could obstructpositive drainage.

7. Flush gutters and downspoutsonce all debris is removed towash away any remaining dirt ormaterials.

8. Keep subsurface drains clear ofdebris. Remove all accumulatedmud or dirt that could enterdrainage system.

Roofs can occasionally growmoss, and it should be dealt withimmediately in a manner that willnot degrade collected rainwater.Downspouts should be discon-nected during the demossingprocess. More information ondemossing can be found atwww.uaf.edu/coop-ext/

68 | Design for Water

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publications (search: demoss-ing); at www.pesticide.org /roofmoss.pdf; and atwww.cleanwaterservices.org.

Downspout FiltersDownspout filters such as theLeaf Beater® and the Leaf Eater®provide a second chance to cap-ture and remove debris that

might enter a rainwater storagesystem. They can be used inlineprior to a roof washer or first-flush diverter. First-flush devicesisolate the first runoff from acatchment surface while allow-ing the additional runoff to passby. They can use floating balls,sinking balls, flaps, or can bebased on the capacity of a vessel.

Equipment for an Active Rainwater Catchment System | 69

Downspout attachedto a gutterH

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Gutter

Page 89: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

70 | Design for Water

Gutter wedge

Snap-on gutterprotector

Perforated gutterprotector withmesh screen

Page 90: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

A sand filter is an option forfiltering rainwater prior to storage.Sand and gravel will remove somecontaminants, and if combinedwith limestone, the acidic natureof the rainwater will be neutral-ized. A sand filter requiresbackwashing regularly to dis-courage bacterial growth thatcan create a crust layer on thesand and cause clogging of thesand’s top layer. Sediment willadd to the clogging. The sand

should periodically be replacedwith new sand. The sand used inthese filters should be washed,screened beach or quarry sand.The filter should also have alarge surface area with the outletpipe equaling the inlet pipe size.

MAINTENANCE OFDOWNSPOUT FILTERS

1. Clean filter with warm soapywater or rinse well every threeto six months.

Equipment for an Active Rainwater Catchment System | 71

Louvered gutterprotector

Helmet-like gutterprotector

Page 91: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

2. Check that the drop from gutterremains vertical. Check to ensurethat the bulk of water is landingcentrally and towards the back ofthe leaf and debris filter screen.

3. Check for any obstructions andsigns of damage to the leaf anddebris filter.

First-flush Devicesand Roof WashersFirst-flush devices range in sizeto meet the demand of the rain-

water catchment system. Thesediversion devices can be part ofthe downspout, be separate froma tank or cistern, or be attachedto a tank or cistern. They can bebelow grade for large stormwatercollection systems, where theharvested water is used fornonpotable purposes such aslandscape irrigation, carwashsupply, or toilet flushing. Thesize and volume depend on theamount of water being diverted

72 | Design for Water

Australian Leaf BeaterFRain Head

A high-performance rainhead with adjustable

elliptical primary screen.Contains interior stain-less steel low-flow-ratesecondary screen for

use when connected toan under-eaves tank

SOURCE:Adapted from Rain

Harvesting Pty Ltd. 2006

Australian Leaf EaterFRain Head

A high performance rainhead for heavy rainfall

areas—also used as a debris-removing device in urban

areas. Contains primary andsecondary screens.

SOURCE:Adapted from Rain

Harvesting Pty Ltd. 2006

Page 92: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

to a storage system and the ulti-mate use of the harvested water.

For any first-flush diversiondevice to work efficiently—espe-cially for potable systems—thecontaminated water must be sealedoff so the rainwater flowing onto the storage cistern(s) does notsiphon off the contaminated waterfrom the first-flush device chamber.

First-flush diverters shouldoperate on a predetermined andset volume and the contaminat-ed water should be sealed offfrom the flow of clean water.First-flush diverters that operateon an estimated open flow rateare typically accurate enough toguarantee that most bacteriahave been flushed from the roof

Equipment for an Active Rainwater Catchment System | 73

First-flush on a Hawaiianrainwater tankT

RIS

HA

MACO

MBER,U

NIV

ERSI

TY

OFH

AW

AII

AT

MAN

OA

LEFT:Typical standpipeRIGHT:SafeRain© VerticalDiversion Valve

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HARVEST

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LTD

2006

SOU

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AFE

RAIN

2003

Page 93: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

prior to closure. Since the goal isto not waste valuable clean water,the most efficient and safest way

to ensure that the appropriateamount of water is diverted is toassess the contamination on the

74 | Design for Water

Australianfirst-flush

Bafflefirst-flush

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006

S OU

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DAPTED

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©20

03

Guidelines for residential first-flush quantities

Rooftops of 1,000 square feet or smaller . . . . . . . . . . . . . . . . . . . . . . . . 5–10 gallons

Rooftops of 1,000 square feet or larger . . . . . . . . . . . . . 10 gallons/1,000 square feet

Guidelines for surface catchment or for very large rooftops

Rooftop or surface catchment of 43,560 square feet or larger . . . . . . . . . . 500 gallons

(1,000 gallons if surface contains excessive soil, dust, or debris). Multiple first-flush devices instead of alarger first-flush may be required depending on slope of the catchment surface and time required for rainwaterto reach the first-flush device.

Page 94: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

roof and calculate a diversionamount based on that assess-ment. A set pre-sized diverterchamber with a free-floating balland seat incorporating a flowcontrol release valve is the opti-mum diversion unit.

If the water diverter does nothave a self-sealing device, it is bestto have it drop off a horizontallength of pipe away from thedownspout so that the roof waterdoes not drop directly into the

water diverter and pick up contam-inants as it travels to the cistern.

MAINTENANCE OF FIRST-FLUSHDEVICES AND ROOF WASHERS

1. Contaminated water in the first-flush device should be drainedeither manually or automaticallyafter each rainfall event.

2. Check for clogs and workingability of roof washers prior torainy season.

Equipment for an Active Rainwater Catchment System | 75

Floating ballfirst-flushSO

URCE:A

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006

Typical stand-pipefirst-flush

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3. If device is not self-cleaning,check roof washers immediatelyafter each rainfall event to emptyany standing water.

4. Large below-grade systemsshould allow evaporation orfiltration of first-flush water.

5. If petroleum-absorbent pillowsare added to the first-flush cham-ber they should be evaluated forsaturation/absorption capacityevery year to determine quantity

of materials washed off thecatchment surface to the first-flush device. Multiple petroleumpillows may be needed; followmanufacturer’s guidelines.

6. Large first-flush devices shouldbe evaluated yearly for sedimentand debris content, and cleanedif needed.

7. Debris shields and vegetationtraps should be evaluated toguarantee unrestricted flowsprior to rainy seasons.

76 | Design for Water

First-flush locationwithout a self-sealing device

Equipment below-ground access

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Downspout Diversion to aRainbarrel or RainchainRainbarrels collect rainwater fornonpotable uses. Even the lightestof rainfall can fill a rainbarrel.Rainbarrels should have a topmesh screen or a plastic lid toact as a barrier to mosquitos.Even with barriers, insect eggsmay enter a barrel with rainwa-ter that has been sitting on acatchment surface or in a gutterfor a period of time.

Mosquito dunks can beused in rainbarrels as well asin a cistern to kill mosquitolarva. It is recommended thatgutter guards or protectors andleaf screens be used prior torainbarrel storage. Rainbarrelsshould be equipped with over-flow outlets, hose connections,multiple barrel attachmentdevices, and a drain plug, andshould be placed on a stablefoundation.

Equipment for an Active Rainwater Catchment System | 77

Debrisbasket lidH

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Debrisbasket

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Page 97: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

Rainchains should besecurely attached to the gutterand, in potentially windy areas,attached to the ground.

MAINTENANCE OF RAINBARRELSAND RAINCHAINS

1. Check rainbarrel before rainyseason to ensure overflow isclear and directed to the appro-priate location.

2. Check rainbarrel before rainy sea-son for leaks and cracks, and checkall connection hoses for wear.

3. Check rainbarrel top mesh forholes and debris accumulation.Remove all obstructions andreplace torn screens.

4. Add mosquito dunk as recom-mended by manufacturer for thecapacity of rainbarrel.

5. Regularly inspect rainchain con-nections at gutter and groundlevel for wear and tear and toguarantee positive drainage.

6. If rainchains are leading rain-water to a subsurface drain,

78 | Design for Water

Below-grade drywellfirst-flush conversion(for nonpotable use)

Below-gradestormwater first-flush(for nonpotable use)

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Page 98: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

inspect drain inlet for debrisaccumulation.

7. Inspect splash pad for properplacement and positive drainageaway from adjacent buildings.

Storage SystemsCisterns and tanks on the mar-ket range widely in size andmaterial. No matter what type

of storage system is selected, thebase or footing must be leveland compacted. Steel tanks,which contain liners, typicallyrequire a concrete base.Concrete, fiberglass, or plastictanks do not require a concretebase or a liner. Some sites willnot accommodate large storageunits below the elevation of the

Equipment for an Active Rainwater Catchment System | 79

Below-grade storm-water first-flush (fornonpotable use)

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LEFT:Rainchain at spaRIGHT:Rainchain from extendedgutter at spa

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Page 99: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

structure or surface receiving therainwater and therefore require asmaller storage unit from whichthe initially harvested water canbe pumped to the main units.

Tanks and cisterns are notmeant to be airtight. Some vent-ing is required to allow pressureadjustments in the storage sys-tem. Below-grade tanks andcisterns must be able to with-stand surface loads. One-pieceunits should be tested for leak-age prior to installation.

Permanent-access ladders toabove- or below-grade tanks andcisterns are optional.

Pumps may be required: iftanks are below-grade; if there isinsufficient gravity to feed thedemand; if the captured waterneeds to be distributed to ahigher elevation; or if the waterneeds to be distributed underpressure. A qualified plumbershould be consulted to set pumptypes and sizes. Typically in potablesystems a floating pump intake,

80 | Design for Water

LEFT:Rainchain directingrainwater to below-

ground storageRIGHT:

Butterfly roof, rainchain,and splash pad on

commercial building HEATH

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Rain cups

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Equipment for an Active Rainwater Catchment System | 81

LEFT: Linked rainbarrelsRIGHT: Rainbarrel

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Rainchain groundconnection

Rain cups

Page 101: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

to remove and use the water justbelow the surface, is best toaccess the highest quality ofwater in the cistern. When highfiltration is used or water qualitydirectly from the tank is not anissue, a well pump may be used.

Water level gauges can beelectronic for above- or below-grade tanks. Above-grade tankshave the option for simpledevices. The Levitator is a stor-age tank level indicator that ison a pulley and counterweight

system with a free hanging ballon the outside of the tank, adja-cent to the wall of the tank, thatrises or lowers with the level ofthe water inside the tank. TheLiquidator is a tank level indicatorthat is similar to the Levatator,but the external level indicator isin a tube to protect it from windand other elements. The Dipstikis a sliding pole mounted to thetop of a tank that slides up as thewater rises and slides down asthe water lowers. There are other

82 | Design for Water

Rainchain/rain cupground connection H

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Private residence whichhas an 18,000-gallon

TimberTank in the back yardfor rainwater collection

JACK

HALL,S

PEC-A

LLP

RO

DU

CTS,

INC.

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Equipment for an Active Rainwater Catchment System | 83

JACK

HALL,S

PEC-A

LLP

RO

DU

CTS,

INC.

JACK

HALL,S

PEC-A

LLP

RO

DU

CTS,

INC.

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Private residencewhich has an8,800-gallon tank

TOP LEFT:New BraunfelsUtilities five15,000-gallon tanks

TOP RIGHT:Metal tank roof

MIDDLE RIGHT:Metal tank in woodsBOTTOM LEFT:Old metalrainwater tankBOTTOM RIGHT:Tanks above house

Page 103: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

tank level indicators such as theLevel Devil that are similar tothe Liquidator, and equilibriumtubes that show water in a tubeat the same height as the waterin the tank. An additional prod-uct is a new tank level indicatorthat has been brought to themarket by Rain Harvesting PtyLtd out of Australia. It is calledRain Alert and is a combinationtransmitter (attached to thetank) and receiver (inside the

house) that can function withina 650-foot range.

MAINTENANCE OF STORAGE SYSTEMS1. Inspect all inlets and outlets before

and after each rain event to removeblockages or repair broken parts.Clean any and all screens.

2. Inspect all access lids to ensureseals are tight enough to deterinsects and animals.

3. Inspect above-grade tank sidesfor damage and leaks. Repair

84 | Design for Water

LEFT:Corrugate metal

pipe cistern

TOP RIGHT:Tanks under deck

BOTTOM RIGHT:Wooden Tank

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SHAW

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ATLEY,

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ATLAN

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Rain Alert transmitteron tank

SANDY MURDOCH, RAIN HARVESTING PTY LTD

Rain Alert receiver in thehouse with a small LCD read-

out panel that continuallyshows the tank water level

SAN

DY

MU

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OCH,R

AIN

HARVEST

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PTY

LTD

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any problem areas.

4. Check foundation or base forany settling or cracking, initiallyafter each rain event, eventuallyon a yearly basis.

5. Check all seams for leaks.

6. For potable supplies, checkwater quality monthly.

7. Maintain mosquito control ifmosquitoes are breeding.

8. Empty below-grade tanks period-ically (every 3 to 5 years) to

check for leaks, waterproofingdamage, and any structural dam-age. Checking at the lowest stor-age point may also be efficient.

9. Check all pumps and other work-ing equipment—such as alterna-tive water supply on/off switch—every six months to guaranteeworking condition.

10. Maintain air gap if alternativewater source is used to fill tanksor cisterns during dry periods.

Equipment for an Active Rainwater Catchment System | 85

Vertical Corrugated metalpipe (CMP) cistern

Carwashreclaim pit

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Potable Water TreatmentTechnologiesCollected rainwater can bepurified for drinking watersupplies. An initial water testmust be conducted to evaluateharvested water content. Asmentioned earlier, the rainwatercontent will be dependent on thecatchment surface, gutter, anddownspout materials. Below aretypical water treatment tech-nologies; additional steps and

filters may be required for vari-ous systems.

Absorption: Carbon filters pro-vide absorption.

Ultraviolet light: Ultraviolet lightdisinfects water by reducingthe amount of heterotrophicbacteria present in the water.

Reverse osmosis: Water passesfrom a more concentratedsolution to a more dilutesolution through a semi-

86 | Design for Water

SOU

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DAPTED

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OEW

HEELER

RAIN

FILT

ERS

OFT

EXASLLC

Above-gradecistern

German cistern withWISY filter, submersiblepump, and overflow/

multi siphon

Flow calmingdevice

Page 106: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

permeable membrane. Mostsystems should incorporatea cyst and particulate pre-and post-filter in additionto the membrane.

Distiller: Water is heated to theboiling point and the watervapor is collected as it con-denses, leaving many of thecontaminants behind, par-ticularly the heavy metals.

Ozone: Naturally occurringallotrope of oxygen has thehighest oxidation potentialof all available oxidants.

Inorganic and organic mate-rials can be oxidized byozone more rapidly and atlower residual concentra-tions than by other chemicalmeans. Ozone is typicallyaspirated via high-efficiencyinjectors while the cisternwater is circulated through aside-stream contacting sys-tem or through a bottom-of-cistern diffusion grid.

There are two styles of watertreatment:

Point-of-entry system: Water is

Equipment for an Active Rainwater Catchment System | 87

Rainwater and othercontrol systems mountedon wall inside the EcoBuilding, Phoenix, AZ

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Various harvested rainwaterpurification processes

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88 | Design for Water

treated prior to entering thebuilding.

Point-of-use system: Water istreated for single use, suchas kitchen or bathroom, andcan include the followingtechniques:

• Bottled water

• Faucet mounted

• Countertop connected tosink faucet

• Plumbed to separate tap

• Pour-through products orgravity drip

• Counter-top manual fill

MAINTENANCE OF DRINKING WATERFILTRATION DEVICES

1. Test water quality frequently,every six months minimum.

2. Change filters more often thansuggested in manufacturers’guidelines.

3. Check for leaks daily, or weeklyat a minimum.

4. Ozone treatment of water storedin cisterns is an option for main-taining water quality.

5. All disinfection should occur afterfilters and prior to distribution, asfilters can become infected.

Following is a sample waterrunoff worksheet, water budgetworksheet, and a worksheetspecific to potable uses only.

RainPCThe RainPC, made in theNetherlands, is a miniaturewater treatment plant that canprovide household water security.

RainPCfeatures

SOU

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TERN

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Month Area 1 Area 2 Area 3 Area 4 Total Monthly

January _____________ _____________ _____________ _____________ _____________

February _____________ _____________ _____________ _____________ _____________

March _____________ _____________ _____________ _____________ _____________

April _____________ _____________ _____________ _____________ _____________

May _____________ _____________ _____________ _____________ _____________

June _____________ _____________ _____________ _____________ _____________

July _____________ _____________ _____________ _____________ _____________

August _____________ _____________ _____________ _____________ _____________

September _____________ _____________ _____________ _____________ _____________

October _____________ _____________ _____________ _____________ _____________

November _____________ _____________ _____________ _____________ _____________

December _____________ _____________ _____________ _____________ _____________

Total MonthlyGallons _____________ _____________ _____________ _____________ __________________________ _____________ _____________ _____________ _____________

Formula: Area of Amount of Catchment Conversion Runoff inCatchment Rainfall Efficiency Factor GallonsSq. Ft. in Feet Gal./Cu. Ft.(Length x Width) X (Inches/12) X (%) X (7.48) = (Total)

RUNOFF WORKSHEET

Runoff Worksheet (To be used incalculating runoff quantities)

Equipment for an Active Rainwater Catchment System | 89

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90 | Design for Water

Irrigationrequirement

Irrigationrequirement

Totallandscape

Runoffminus

Excess

runoff

fromstorage

frommunicipalsupply

irrigationrequire

ment

Availablerunoff

landscapeirrigation

tostorage

Accumulative

(Required

tosupplem

ent

(Norainw

aterin

Month

fore

stablishedplants

supply

require

ment

(Notused

each

month)

storage

irriga

tionrequireme

nt)

storage

tank)

January

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NONPOTABLE

WATER

BUDGET

WOR

KSHEET

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Equipment for an Active Rainwater Catchment System | 91

Number of Users . . . . . . . . . . . . . . . . . . . . 2

Step 1 Gallons per day/person . . . . . . . . . . . . . . . 70

Gallons required per day . . . . . . . . . . . . . . . 140 (users x gpd/p = )

Days in residence/year. . . . . . . . . . . . . . . . 365Step 2

Total water use per year . . . . . . . . . . . . . . . 51, 100 (gpd x days = )

Rainfall (inches) . . . . . . . . . . . . . . . . . . . . 7

Step 3 Water per sq. ft./inch of rain . . . . . . . . . . . 0.623

Gallons water/sq. ft./year . . . . . . . . . . . . . 4.36 (rainfall x 0.623) = )

Total water needed per year . . . . . . . . . . . . 51, 100

Step 4 Gallons water/sq. ft./year . . . . . . . . . . . . . 4.36

sq. ft. collection area needed. . . . . . . . . . . . 11,720 (water needed/g sq. ft./year = )

Days storage required (varies). . . . . . . . . . . 90

Step 5 Gallons required per day . . . . . . . . . . . . . . . 140

Gallons of storage required . . . . . . . . . . . . . 12,600 (days stg x gpd = )

System requirements for the above budget are as follows:Rooftop catchment collection area required for this design based on rainfall in the surrounding area: 11,720 sq. ft.Storage capacity required to supply system for periods without rain (summer): 12, 600 gallons

NOTE: The example shown here would require several catchment areas such as a house, patio, any sheds, and possibly any paveddrives. It may not be possible to assemble an 11,720 sq. ft. catchment area, which means an alternate water source would berequired for a potable system.

POTABLE WATER BUDGET WORKSHEET

Potable Water Budget Worksheet (Tobe used in calculating a water budget)

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Impurities and contaminants areremoved from the stored rain-water as it passes upwardthrough the RainPC’s five-stagepurification process. The rain-water first flows through apre-filter that takes out all parti-cles larger than 5 microns. Itthen passes through a drum-cage containing ceramic spheres

with silver colloids and thenthrough three activated-mineralcomposite Xenotex-A cartridges,an activated carbon filter withsilver particles, and finally a spe-cially developed low-pressureMF membrane filter.

After passing through thiscompact unit, which requiresonly low gravity pressure to

92 | Design for Water

Stay-n-Play PetRanch rainwater system

roof washer

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function, the water is ready todrink. A RainPC should beplaced at an elevation lower thanthe cistern or the cistern water

could be pumped to an elevationhigher than the RainPC to allowgravity to push the rainwaterthrough the unit.

Equipment for an Active Rainwater Catchment System | 93

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LEFT (TOP TO BOTTOM):A Pioneer Galaxy waterstorage tank in California

Rainwater tank atWollongong Botanic Gardenin New South Wales, AU

RIGHT (TOP TO BOTTOM):

Tank painted like a turtle

Tank painted like a ladybug

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TECHNICAL DATADimensionsHeight: 32 inchesDiameter body: 12.4 inchesDiameter assembled: maximum

18.8 inches

WeightUnit assembled, including

cartridges: 55 lbs

Xenotex-A cartridge: 6.6 lbsCAG cartridge: 4.4 lbs

MaterialsPVC house bottom, body,

and topSteel clamp ringNickelbrass faucet

Brass water meter

Pressure Reduction ValveFor maximum 6 bar to 0.2 bar

ConnectionsDrinking water outlet valve,

diameter 1/2 inchRainwater inlet, diameter 1/2 inchDrain outlet, diameter 1/2 inchWater meter outlet, diameter

3/4 inch

CostsThe cost of a rainwater har-vesting system varies greatlydepending on the extent of thesystem. Some costs of a system

94 | Design for Water

VARIOUS STORAGE TANKS AND AVERAGE COSTSPER BUILDING MATERIAL

Material Estimated Cost Typical Size

Barrel Free, to $300 per barrel 200 – 500 gallons(Plastic Rain, wooden whiskey, or metal)

Concrete or Ferro-Cement $0.35 up to $1.50 per gallon Any(Precast concrete tanks)

Fiberglass $0.50 to $2.00 per gallon 500 – 20,000 gallons

Metal $0.30 to $2.79 per gallon 150 – 104,000 gallons(Corrugated with liner, galvanized steel)

Polyethylene $0.50 to $1.90 per gallon 210 – 5,000 gallons

Polypropylene $0.35 to $1.00 per gallon 290 – 20,000 gallons

Welded steel $0.80 to $4.00 per gallon 1,000 – 1 million gallons(Bolted stainless steel)

Wooden $0.88 to $2.06 per gallon 700 – 2 million gallons(Treated wood with liners)

Stone Very expensive; up to $1.00 per Anysquare foot of tank surface area

Crates: Invisible StructuresRainStore 3 $8.00 per cubic foot Any

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The 2-gallon pressuretank used for rainwaterin bathroom and forevaporative coolers

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should be assumed buildingcosts such as gutters on resi-dential homes or gutters anddownspouts on commercialbuildings. Retrofitting abuilding is always moreexpensive than building thecomponents into the originaldesign. Double plumbing forflushing toilets or washingclothes with rainwater shouldbe an option with originaldesigns as it may be too costlyto retrofit a building for thisoption. If a building is in aremote location with no munic-ipal supply or well available, thecosts may be less of an issue.

The single most expense in asystem is the storage tank or cis-tern and price is based on thequantity of water to be storedand the material the storage is

made from. The intended usemay dictate the material of thestorage tank. Storage units canrange in price from a low $0.30per gallon to a high of $4.00 pergallon.36

Gutters used for watercollection should be made fromvinyl, plastic, aluminum, or gal-valume. The gutters made fromthese materials can range inprice from $0.30 per lineal footto $12.00 per lineal foot.

Vertical and horizontal boxroof washers can range in pricefrom $460 to $1,000.

Pre-filters can range in pricefrom $50 each to $80 for largersystems.

Pressure tanks range in pricefrom $200 to $1,000.

Pumps range in size andprice from a 1-horsepower

Equipment for an Active Rainwater Catchment System | 95

LEFT (TOP TO BOTTOM):Australian Slimline tank;note the leaf filter basketand the first-flush standpipe on the downspout,and rainwater piped backinto the house for laundryand flushing toilets

A 2,000-liter residentialrainwater tank with a standpipe and leaf catcher

RIGHT (TOP TO BOTTOM):Private residential PioneerGalaxy water storage tankin Western Australia

Three black polywater storage tanks,2,340 gallons each

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Grundfos at $585 to a 3/4-horse-power Gould at $585 to a1-horse power Gould at $635.

Filters can be cartridge filtersets (includes 5 micron and 3micron charcoal) at $100; onemicron filters at $265; reverse-osmosis filters at $400 to $1,500;UV filters at $300 to $1,000 withreplacement bulbs costing $80 to$100; ozone disinfection systemsat $700 to $2,600; and chlorinedisinfection systems at a manualcost of $1 per dose or $600 to$3,000 for an automatic system.Floating cistern filters costapproximately $265.

Prices quoted are approxi-mate 2006 costs and were priceestimates from:

Texas Guide to RainwaterHarvesting; braewater.com;specallproducts.com;invisiblestructures.com;plasticstoragetanks.com;

rainwatercollection.com; andrainwatermanagement.com.

An installed rainwater har-vesting system providing all sixcomponents including potablewater suited for a four-personhousehold may cost as much as$22,000.37 A commercial projectcould install a rainwater harvestingsystem for less if undergroundflood retention is proposed anddrywells are eliminated.Although there are many passiverainwater techniques that costvery little—even a barrel can beused for rainwater collection—there is a wide range of costs,depending on an owner’s com-mitment to water conservation.Cost-recovery times for a sophis-ticated residential rainwaterharvesting system in other partsof the modern world have beenestimated to be around 16 years.38

96 | Design for Water

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Chapter title | 97

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98 | Design for Water

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Pumpkin tank fromSri Lanka

Equipment for an Active Rainwater Catchment System | 98

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Underground brick dometank from Sri Lanka

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THE FOLLOWING is a collectionof case studies that will pro-

vide the understanding to attaindreams— dreams of catchingand reusing water that is provid-ed to a site through natural orartificial means. There are sev-eral sections to this collectionstarting with landscape infiltra-tion and continuing throughindividual private rooftopcatchment systems to multiplebuilding systems that supportresidential subdivisions.

Commercial rooftop rain-water catchment systems,industrial rooftop rainwatercatchment systems, water catch-ment systems for schools of alllevels, parks, and interpretivecenter systems, and large scalemunicipal systems are providedfor reference and further study.

Alternate water systems thatinclude fog collection, coolingtower blowdown water collection,air conditioning condensatewater collection, and greywater

When the well is dry,we learn the worthof water.

— Ben Franklin

Case Studies | 99

A private residential35,000 gallonPioneer Galaxywater storage tankused for rainwatercollection in the hillcountry of Texas

CaseStudies

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collection are provided todemonstrate the potential forsaving purified municipal water.Rainwater catchment for wildlife

is also provided as an example ofhow water can be provided tolocations that do not have a nat-urally accumulated water source.

100 | Design for Water

Two eastern redcedar wood tanks

outside a retail building JACKHALL,S

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C.

Location: Portland, Oregon

Type of system: Passive rooftop for infiltration

Year installed: 2003

Annual rainfall: Approx. 52 inches

Catchment area: Rooftop – 5.5-acres

Containment: None

Annual quantitycollected: Approx. 6.9 million gallons

Water usage: Rain garden infiltration

Equipment involved: Pumps – NoneCistern level controls – NonePressure tank – NoneFilters – Natural plants and soil

Contact: Landscape Architect: Mayer/Reed, Portland,Oregonwww.mayerreed.com

Landscape Infiltration

OREGON CONVENTION CENTER—PORTLAND, OREGON

The Oregon Convention Centerstormwater garden is located onthe south side of the buildingbetween the building and theadjacent road. The 5.5-acre roofdrains via downspouts in fourlocations along the linearstepped garden. While most ofPortland’s stormwater drainsinto the city’s sewer system, thissite was granted a direct pipe tothe adjacent Willamette River.However, instead of dumpingthe potentially polluted sitewater directly into the river, theproject Landscape Architectdecided to infiltrate the runoffwater, and allow the plantsand soil to filter pollutants andmaintain water quality levels.

The rain garden mimics astream flowing through the site.The rainwater travels througha series of shallow, cascading,ungrouted rock-lined pools.Each pool is separated by lowrock weirs to allow the waterstanding and infiltrating time.The weirs also slow the waterallowing any sediment to dropout before continuing on down-stream. Once a pool is full therainwater spills over the weirand drops about 18 inches intothe next pool. This streamtravels 318 feet, and averagesabout 6 feet wide. The dramaticgarden is made by using a vari-ety of flat flagstone, small riverrock, angular retaining wall

Page 120: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

stones, and columnar basaltpieces. The channel edge againstthe road is reinforced with asteel plate to eliminate erosionpotential and to maintainstructural stability. The soilsunderlying the rock channel area mixture of sand and Troutdaleformation soil. The soils allowmost of the slow rains to infil-trate quickly.

The rain garden channelends in a detention pond thatalso receives runoff from a205-foot vegetated swale thatcaptures runoff from the truckloading area. In the rare occa-sions the pond fills, there is a30-inch public storm drainpipe installed. The plants areobviously enjoying the extradrink, as they are very lush.

Case Studies | 101

LEFT:Downspout from build-ing to rain gardenRIGHT:Downspout to a less-vegetated channel

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Entry to the OregonConvention Center

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102 | Design for Water

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Signage recognizingthe rain gardens

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First downspout inthe system

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View of the raingardens from the

southwest

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Pedestrian crossings withsignage allow visitors to under-stand the rock channel and thenatural cycle taking place.

Details of this system canbe found in the September 2004edition of Landscape Architecturemagazine, page 64.

Case Studies | 103

LEFT:View of a weirfrom the sideRIGHT:View of a weirfrom aboveH

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SEATTLE NATURAL DRAINAGE SYSTEM—SEATTLE PUBLIC UTILITIES

Seattle’s creeks carry pollutionfrom roadways, streets, andparking lots to the Puget Sound,impacting the food chain thatsupports fish and other wildlifein the area. The fish that areimpacted by this pollution—including salmon and steelheadtrout—are a symbol of thenorthwest, requiring preserva-tion. Therefore, a new solutionfor the rainwater that carriesthese pollutants was needed. TheCity of Seattle approved an ini-tial planning grant to find asolution, and the resulting newconcept is now known as theSeattle Public Utilities NaturalDrainage System.

The concept was initiallyimplemented in a northwestSeattle neighborhood that hadinadequate stormwater manage-

ment. It was initiated in aninnovative study to determinethe potential for cleanup of thepollutants carried by thestormwater runoff. By 2004 theproject had succeeded wellbeyond the initial expectationsand has now been implementedin five new smaller projects andone larger project covering fif-teen city blocks in northwestSeattle’s Piper’s Creek watershed.

This new approach meetsmultiple goals including helpingto manage flooding in neighbor-hoods; improving appearanceand function of streets; provid-ing responsible stewardship ofthe environment; and helpingthe City to meet local, state, andnational environmental regula-tions. The system utilizes soiland plants to substantially

Location: Seattle, Washington

Type of system: Passive rooftop and groundlevel for infiltration

Year installed: 2002

Annual rainfall: Approx. 52 inches

Catchment area: Four block area, 21 acres

Containment: None

Annual quantitycollected: Unknown

Water usage: Rain garden infiltration

Equipment involved: Pumps – NoneCistern level controls – NonePressure tank – NoneFilters – Natural plants and soil

Contact: Seattle Public Utilitieswww.ci.seattle.wa.us.

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104 | Design for Water

Younger rain gardenwhere vegetation hasnot reach maturity; thisis a cascade garden

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Cascade raingarden

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Stepped cascaderain gardens at initial

completion

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decrease runoff by allowing it toinfiltrate to natural subsurfacehydrologic systems and reducepollutants as the water infiltratesthrough the soil. The systemallows nature to restore and con-duct the processes it wasintended to do.

This approach is completedby narrowing roads andconstructing rain gardens orinfiltration cells along the sideof the road. These open-spaceareas left from narrowing of theroads are then designed with

plants and highly permeablesoils. The gardens are interlinkedto create a network of vegetatedswales and “cascades” thatabsorb the stormwater. Theswales run with the contours,and drain into the cascades thatcut and step down the contoursof the development.

The City of Seattle hasdetermined that in additionto the environmental benefitsthe system is providing it is alsoa more cost effective way totreat stormwater than the tra-

Case Studies | 105

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LEFT:Realigned road; notethe curvilinear formRIGHT:Drain for overflowing tothe next rain garden

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Sidewalk betweenthe residential lot andthe natural drainagesystem rain gardens

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LEFT:Drain pipe emptyinginto a rain gardenRIGHT:Rain garden betweentwo drives; this is a raingarden running with thecontours of the land

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ditional approaches.39 Treatingthe stormwater where it fallshas reduced the need to buildand maintain costly treatmentpipes and holding facilities.Seattle Public Utilites estimatesthe Natural Drainage Systemcosts 25 percent less than tra-

ditional roadways and stormdrain facilities.40

Details of this system can befound at Carkeek Cascade NW110th St. on the Seattle PublicUtilities web page, www.seattle.gov/util/services/ (search:Carkeek Cascade).

106 | Design for Water

Location: Friday Harbor, Washington

Type of system: Active rooftop

Year installed: 2005

Annual rainfall: Approx. 42 inches

Catchment area: Rooftop – 5,000 square feet

Containment: Above-grade 30,000-gallon metaltank and one 240-gallon balltank for collecting from all downspouts prior to gravity feed to tank

Annual quantitycollected: Approx. 117,810 gallons

Water usage: Potable water supply

Equipment involved: Pumps – Grundfos 3-horsepowerpumpCistern level controls – YesPressure tank – 60 gallonFilters – UV, 5 and 1 micron,and 3-micron charcoal filter

Contact: Design and installation by TimPope, Friday Harbor, [email protected]

Residential: Single-Family and Multi-Family RainwaterHarvesting Systems

COLE RESIDENCE—SAN JUAN ISLANDS

The Cole Residence is in awooded area on the San JuanIslands. The islands in this partof the United States are havingproblems with their groundwater quality as the saltwater hasbegun to intrude into the supply,and in the area of the ColeResidence there are also prob-lems with barium in thegroundwater. In an effort toeliminate all polluted water the

family has implemented a rain-water catchment system toprovide all potable water. Theremote location of the homealso requires a fire-fighting watersupply that the local fire andemergency trucks can hook intowhen needed.

The home is located 45 feetabove the water storage tank.The rainwater is initially directedto a ball tank that filters the

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Equipment roomwith pumpand filters

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rainwater through gravel in thebottom of the tank. The balltank also works as a manifoldfor directing water from themultiple drain pipes to a gravity-fed pipe that leads into—fromthe bottom—the main storagetank situated below the home.

The main storage tank isfitted with two withdrawingpipes; the first is a vertical pipethat reaches to the tank floor.This pipe remains as a fire-pump apparatus for emergencyuse. The second pipe enters

through the tank floor and isattached to a 3- horsepowerpump and a 60-gallon pressurebuffer tank, which returns tofeed the home above.

The metal tank is linedwith a 35-mm polypropylenematerial that includes a nylonmesh layer to add strength. Theliner sits on a tank floor ofbricks set in sand. It reachesup the walls of the metal tankand is attached at the top of thetank, which is enclosed with ametal roof.

Case Studies | 107

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LEFT:Pressure tank forthe systemRIGHT:Tank with the firehose connection

KEARNEY RESIDENCE—CATALINA MOUNTAINS

Located in the foothills of theCatalina Mountains north ofTucson, the Kearney Residencedisplays an excellent use of slopeto incorporate a rainwater cis-tern. The system was installed in1990 when the existing home wasremodeled. Because the homesite is fairly steep, the cistern topcould be located at an elevationthat permitted its use as a patio.

The site-constructed integral

concrete block cistern uses gravi-ty to feed a hose bibb at its base.No first-flush device is installedprior to the cistern. Water is onlycollected from the rooftop,where very little debris accumu-lates. A hand-held hose is usedto irrigate the desert landscapematerial. The site is augmentedwith swales that lead to plantingbasins, and downspouts that aredirected to adjacent planters.

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108 | Design for Water

Integral cisternwith landscapeplanter below H

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Passive water collectionswale that leads to thelandscape basin

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Location:Tucson, Arizona

Type of system: Active rooftop

Year installed: 1990

Annual rainfall: 11.4 inches in the foothills

Catchment area: Rooftop – 4,000 square feet

Containment: One 7,000-gallon concrete blocktank with stone veneer

Annual quantitycollected: 24,800 gallons

Water usage: Irrigation, nonpotable

Equipment involved: Pumps – NoneCistern level controls – VisualPressure tank – NoneFilters – None

Contact: Richard Brittain, University ofArizona Tucson, Arizonawww.architecture.arizona.edu/people.asp?topic=faculty

Patio above cistern;metal lid on surfaceis the cistern access

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The Camino Blanca Residenceis located on a hillside of SantaFe, New Mexico. The residenceroof drains in multiple direc-tions, requiring thirteen catchbasins to collect all the roofrunoff water. All the capturedwater drains, by gravity, tothree 2,000-gallon Darco tanks.The tanks are made of polyeth-ylene and can be connectedto each other for modular,unlimited water storage capacity.The Darco tanks connect atthe ends, and are nicknamed“OcTanks” due to the eight-sided internal rib design that

gives the tank its strength andrigidity when buried.

These tanks can withstandautomotive and water-truckloading. They are typicallyburied at a 3-foot depth, andequipped with manway risersand vents. The tanks can bemade from virgin polyethyleneresin, which is NSF listed andcomplies with the FDA 21 toallow potable water systems. Ashallow basin is located next tothe tanks for overflow purposes.The pump for this residence is aGrundfos jet pump that suppliesthe irrigation-line pressure.

Case Studies | 109

CAMINO BLANCA—CAMINO CRUZ BLANCA ROAD

Location:Santa Fe, New Mexico

Type of system: Active rooftop

Year installed: 2005

Annual rainfall: Average 14.3 inches

Catchment area: Rooftop – 5,475 square feet

Containment: Below-grade, three 2,000gallons each

Annual quantitycollected: Approx. 40,331 gallons

Water usage: Irrigation water supply

Equipment involved: Pumps – Grundfos MO3-45 jetpump, Hydromatic series 20submersible pumpCistern level controls – Digitalwater quality indicating systemPressure tank – Not availableFilters – Inline conveyance filter

Contact: A Desert Rain System by TheHydros Group Santa Fe,New Mexicowww.thehydrosgroup.com

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The site plan for theproject shows the catchbasins and pipes for col-lecting the rooftop rain-water and the lines tothe Darco tanks; the irri-gation service is alsoshown exiting the tanks

RANCHO SAN MARCOS—CHAPMAN COMPANIES

Rancho San Marcos is a single-family home that wasconstructed to demonstrateinnovative technologies. The

Partnership for AdvancingTechnologies in Housing(PATH), managed and support-ed by the US Department of

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Housing and Urban Development(HUD), conducted the fieldevaluation for the use of greywa-ter and rainwater collectionsystems for the Rancho SanMarcos home. The research wasconducted due to the watershortages in the area.

The greywater system cho-sen was a package system that

included a12-gallon storage(sometimes called surge) tankconnected to a centrifugal pumpand a sand filter with self-clean-ing capabilities. The greywatersystem was purchased from JadeMountain, Inc. of Boulder,Colorado and was connected tothe drainpipes from the bath-room sinks, showers, and

110 | Design for Water

Location:Santa Fe, New Mexico

Type of system: Active rooftop

Year installed: 2000

Annual rainfall: 10-12 inches

Catchment area: Rooftop – 2,300 square feet

Containment: Below-grade, one 1,200-gallonpolypropylene tank for rainwaterand a 55-gallon package greywater system called GURU orGreywater Universal ReclamationUnit, made by Earthstar EnergySystems

Annual quantity Approx. 15,484 gallons of rain-collected: water and approx. 18,000

gallons grey water collected,approx. 27 gallons per day

Water usage: Landscape irrigation water supply

Equipment involved: Pumps – 1.5 horsepower forthe rainwater systemCistern level controls – ManualPressure tank – NoneFilters – Only on the pumpintake of the rainwater pump.The greywater system uses asand filter.

Costs of system: $3,000 per home for the rain-water system and $2,500 perhome for the extra greywaterpipes and GURU system.

Contact: Design and installation byChapman Companies, Santa Fe,New Mexico,www.chapmandcompanies.comRainwater and greywater systemcomponents provided by JadeMountain, Inc. www.jademountain.com (now Gaiam/RealGoods)

TOP: Front viewof the home

BOTTOM: Greywaterand rainwater

equipment access lids

CHAPMANHOMES

CHAPMANHOMES

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bathtubs. The package systemcomes ready to hook up tothe house drainpipes and isdesigned to turn on the self-priming centrifugal HaywardPower-Flo II, 15-amp, 115 volt,3/4-horsepower pump when thesurge tank fills to pump thegreywater through the attachedsand filter.

The pump does have astrainer filter on the suction sideof the line that needs to becleaned monthly. Once the wateris collected and filtered it is

delivered to the site’s six orna-mental fruit trees through a2-inch pipe. The sand filter is0.45-0.55 mm. pool filter sand,and filters out dirt, hair, grease,and other particles. Periodicallythe sand filter must be back-washed to remove theaccumulated debris. A 3-waydiverter valve allows the greywa-ter to be diverted back to thehouse sewer system for back-washing or if the greywatersystem needs repair or cleaning.

The roof top rainwater is

Case Studies | 111

Greywater and rain-water pump andequipment in sumpC

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Greywater sumpschematic

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collected via gutters and down-spouts to a 1,220-gallon plastictank. The buried tank has a 2-foot diameter access hatch witha cover at grade level. An over-flow system consisting of a6-inch perforated pipe runs tothe orchard. A solenoid valveand float switch control thebackup system that is a line fromthe site’s well, which fills thetank when the collected rainwa-ter is exhausted. The switch fillsthe tank with the daily irrigationrequirements of 200 gallons ofwater, leaving approximately1,000 gallons of capacity forrainwater that may be collected.

A 1.5-horsepower pump drawsthe rainwater out of the tankinto an irrigation system thatwaters a rear-yard lawn and sev-eral shrubs as well as shrub inthe front yard.

The landscape irrigationneeds are estimated at 150 to200 gallons daily. By using boththe greywater and rainwatersystems, Chapman Companieswas able to provide an extrawater supply of approximately14,179 gallons, allowing certainshrubs and plants, which arenot normally provided in thebuilder’s landscape package, tobe included.

112 | Design for Water

SINGLE-FAMILY QUADPLEX—TUCSON BARRIO REDEVELOPMENT AREA

These four homes are notattached other than by fencing.The area between the homeswas divided into four court-yards. Each courtyard has three

cisterns, two at the end of theindividual carport and one onthe side of the home. The rain-water gravity-feeds into thecisterns that are 7 feet tall and

Location: Tucson, Arizona

Type of system: Active rooftop

Year installed: 2001

Annual rainfall: 12 inches

Catchment area: Rooftop – 2,000 square feet

Containment: Above-grade, three 370-galloncorrugated metal cisterns

Annual quantity Approx. 40,392 gallons for allcollected: three cisterns

Water usage: Landscape irrigation

Equipment involved: Pumps – GravityCistern level controls – VisualPressure tank – NoneFilters – None

Contact: Design and installation by DaveTaggett, Tucson, Arizona.(No website address available)

View of courtyardand cisterns prior tocarport completion H

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Case Studies | 113

View of the four-homequadplex and carportsfrom the street aftercarport completionH

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One tank on the mainpatio with two in theadjacent yard. Thishomeowner opted toremove one of thecisterns at the end oftheir carport

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Two tanks in adjacentcourtyard at the end ofthe carport

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approximately 3 feet in diameter,holding approximately 370 gal-lons of water.

The cisterns are made fromcorrugated metal pipes that havebeen turned on end to createtanks. The housing architecturefits well with the corrugated

metal pipe cisterns and they adda touch of “artsy” look to thecomplex. The systems areentirely gravity feed; no filtersor pumps are used, and thecollected water is only usedfor a gravity feed landscapeirrigation system.

114 | Design for Water

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LEFT:One tank on theside of one home

RIGHT:One tank in theadjacent sideyard H

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CASA RUFINA—APARTMENT COMPLEX

Casa Rufina is an apartmentcomplex located in Santa Fe,New Mexico with seven residen-tial buildings and a clubhouse.The total roof area collectedfrom is approximately 92,260 sq.ft., which includes catchmentfrom all the buildings as well ascovered parking areas. The roofrunoff is directed to four differ-ent groups of five Darco tanks.Each group of Darco tanks holdsa total of 10,000 gallons.

Two of the tanks aredesigned to overflow to theothers if they reach maximumcapacity; this insures that allrainwater is captured and notlost. Each tank system suppliespressurized water to its own irri-

This site plan showsa typical buildinglayout with catchbasins and lines tothe Darco tanks

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gation system that provideswater for that specific area orgroup of apartments. This sys-tem also has the DRS SwitchingSystem, a specialty systemdesigned by the Hydros Groupspecifically for switching watersupplies in a tank. The rainwatercatchment system was alsodesigned to take on additionalroof catchment water when thenext expansion is built.

The pump system is aHydromatic HE-20 Submersiblesystem. The filter is a GrafUniversal large scale filter systemthat filters 100 percent of thewater conveyed to the cisterns.

Case Studies | 115

Location: Santa Fe, New Mexico

Type of system: Active rooftopYear installed: 2005Annual rainfall: 12-14 inchesCatchment area: Rooftop – 92,260 square feetContainment: Below-grade, four 10,000-gallon

modules of Darco tanksAnnual quantitycollected: 699,873 gallonsWater usage: Landscape irrigationEquipment involved: Pumps – Hydromatic HE-20

submersibleCistern level controls – Digitalwater-quality indicating systemPressure tank – Not availableFilters – Graf Universal largescale filter system

Contact: A Desert Rain System by TheHydros Groupwww.thehydrosgroup.com

Residential Subdivisions: Rainwater Harvesting Systems

RANCHO VIEJO—SUNCOR DEVELOPMENT

Rancho Viejo is a 10,600-acreSunCor Development locatedsouth of Santa Fe, New Mexico.Due to high water-impact feesand the potential to maximizethe number of units, rainwaterharvesting systems were proposedto extend the water allocationprovided to the development.Other water conservation meas-ures were implementedincluding low-flow fixtures, pro-hibiting swimming pools, andimplementing xeriscape land-scapes. Irrigated areas were alsolimited to 1,000 square feet.

The rainwater is directed asit splashes down to the ground

from the home’s canales throughcobble-filled catch basins withnon-permeable liners to pipesthat lead to the undergroundstorage tank. Each system costsbetween $5,500 and $6,900. Eachhome system collects its ownrainwater for that specifichome’s use. The average waterusage per unit in 2001 was58,600 gallons, and with theimplementation of these rain-water systems the average unitwater usage is estimated to dropto 29,300 gallons. SunCor nowbuilds approximately 140 newhomes yearly, each with a rain-water harvesting system.

Location: Santa Fe, New Mexico

Type of system: Active rooftop

Year installed: 2003

Annual rainfall: Approx.13 inches

Catchment area: Rooftop – Approx. 2,500square feet

Containment: Below grade, one 600- or1,200-gallon polypropylene tank

Annual quantitycollected: Approx. 18,513 gallons

Water usage: Landscape irrigation water supply

Equipment involved: Pumps – 1-horsepower GrundfosMQ-35Cistern level controls – ManualPressure tank – NoneFilters – Cobbles

Contact: Design and installation by AquaHarvest, Santa Fe, New Mexicowww.aquaharvest.comwww.ranchoviejo.com

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116 | Design for Water

Bobcat loaderdelivering and

placing a cistern

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LEFT: Cistern locatedin hole with pipes

in placeRIGHT: One recently

placed and connected1,200-gallon cistern

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Rancho Viejoentry signage

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WILKES COUNTY LOG HOME SUBDIVISION—HOME WATER SUPPLYFOR 250 LOG HOMES

Case Studies | 117

TERRYM

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Dual cisternsbeing connectedto drainpipes

The Wilkes County Log HomeDevelopment is a projectcurrently under construction.When completed, the projectwill have 250 log homes withsix different designs, four condobuildings with five condo unitsper building, and a clubhouseand pool. The rainwater catch-ment systems are the primarywater supply for each home.

Each system captures rainwaterfrom a 3,200 square foot metalroof, and is estimated to costapproximately $10,000 perunit. The designs will be integralto the design of the log homes.

The water enters the tanksthrough a first-flush system of avortex fine filter to removeleaves and debris, and a smooth-ing inlet to prevent stirring up of

Location: Wilkes County,North Carolina

Type of system: Active rooftop

Year installed: 2006

Annual rainfall: Average 51.5 inches

Catchment area: Rooftop – Two-hundred fiftyhomes, each with 3,200 squarefoot catchment area

Containment: Above- and below-grade eachhome, 5,000-gallon storage intwo poly tanks

Annual quantity Approx. 144,401collected: gallons per home

Water usage: Potable water supply

Equipment involved: Pumps – 1-horsepower sub-mersible pump, and a boosterpump in the houseCistern level controls – FloatswitchPressure tank – Not availableFilters – First-flush, and tankfiltration is a WISY floating filterin the tank, UV light, one sedi-ment filter, and a carbon filter

Contact: Rainwater ManagementSolutions, Salem, Virginiawww.rainwatermanagement.com

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BOTTOM: A typical loghome in a western loghome subdivision

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sediment that may settle in thebottom of the tanks. Each rain-water system will have twolinked 2,500-gallon poly tanks.

The water in the tanks isretrieved with a normal switch-suction, submersible multiple-stage pressure pump. The pump

is fitted with a floating filterintake system and a float switch toturn off the pump if water levelsgo below the minimum. Thetanks are insulated for the coldweather experienced in the area,and have a pneumatic level indi-cator to display the water level.

118 | Design for Water

Typical log homein a remote area H

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RANCHO ENCANTADO—RESORT AND CABINS

Rancho Encantado has quite along history. Current historystarts with the following excerptfrom the resort’s web site:

In 1967, Betty Egan, awidow from Cleveland, Ohiowith children in tow, foundthe ranch and immediatelyfell in love with the settingand the dream of a new life.In 1968, she re-christened theproperty Rancho Encantadoor Enchanted Ranch, andopened the doors to guestsonce again. Her familialsense of hospitality quicklybecame legend. She hadcreated a world-class resort

with the casual ambiance ofa ranch, all aspects reflectingher strong sense of the waythings ought to be.

Over the years the legend ofRancho Encantado grew asBetty’s dedication to herspecial brand of hospitalityattracted scores of famousguests including PrinceRainier and Princess Graceof Monaco and family,Princess Anne, The DalaiLama, Maria Callas, HenryFonda, Jimmy Stewart, JohnWayne, and Frank Capra,among others.

The sense of hospitality

Location: Tesuque, New Mexico

Type of system: Active rooftop

Year installed: 2006

Annual rainfall: Average 13 inches

Catchment area: Rooftop – Total unavailable,includes resort building and 50cabin buildings

Containment: Below-grade Atlantis D-Raintanksystem, 160,000 gallons

Annual quantitycollected: Unavailable

Water usage: Landscape irrigation

Equipment involved: Pumps – Hydromatic HE-20submersible pumpCistern level controls – Digitalwater-quality indicating systemPressure tank – Not availableFilters – Graf Universal largescale filter system

Contact: A Desert Rain System by TheHydro Group, Santa Fe,New Mexicowww.thehydrosgroup.comwww.rancho-encantado.com

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Case Studies | 119

Atlantis rainwaterstorage tank schematic

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Atlantis pumpbasin schematic

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This site plan shows a typi-cal cabin cluster, how theAtlantis tanks are located,and how the rainwaterpipes connect the down-spouts to the tanks

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that Betty Egan created herewill live on. She welcomedher guests to Rancho as shewould to her home; thisspirit is at the heart of thenew Rancho Encantado. Wecontinue to honor her andher spirit as we move forward.

Today the luxury resort,Rancho Encantado, located inTesuque, New Mexico, has arainwater catchment system. Thesystem involves the multitude ofguest cabin clusters conveyingwater to a tank system specific to

the individual cabin cluster. Thetotal volume stored is 160,000gallons. Water is also capturedfrom the pool deck area as wellas the courtyards within thestructures. Each of the catchmentsystems ties into a DRS SwitchingSystem (a system designed by TheHydros Group; it uses no elec-tricity and has no moving parts).The pumps are Hydromatic HE-20 Submersible Systems and thefilters are Graf Universal largescale filter systems that filter 100percent of the water conveyed tothe cistern systems.

120 | Design for Water

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Convenience filter schematic

CLUB CASITAS DE LAS CAMPANAS—LUXURY GOLF COURSE DEVELOPMENT

The Club Casitas de LasCampanas is a portion of thelarger Las Campanas luxury golfcourse development on 4,800acres located in Santa Fe, NewMexico. Las Campanas has two18-hole world-class JackNicklaus Signature golf cours-

es—the Sunrise and the Sunset.In addition to the golf courses,there is a spa and tennis centerwith six tennis courts, indoorand outdoor pools, and a gym.The community is surroundedby more than 66,000 acres ofBLM land providing vistas, land

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This site plan shows atypical casita cluster andhow the Darco tanks arelocated, as well as how

the rainwater pipes connectthe downspouts and catch

basins to the tanks.

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for horseback riding, and hikingopportunities. Horses can alsobe boarded at the 92-stall eques-trian center on the property.

Each home in the communi-ty has a rainwater catchmentsystem. At the Casitas, ten unitshave been linked into two clustersof Darco tanks providing 18,000gallons of water storage in onecluster and 16,000 gallons in theother. The system will supplywater to the irrigation systemthrough the DRS switching system.The pump system used is aGrundfos SQE SubmersibleSystem. The filter system is theGraf Universal large scale filtersystem that filters 100 percent ofthe water conveyed to the cisternsystem. The system also has anautomatic dial feature that willnotify The Hydros Group if any-thing should malfunction.

Case Studies | 121

Location: Santa Fe, New Mexico

Type of system: Active rooftop

Year installed: 2006

Annual rainfall: Average 14 inches

Catchment area: Rooftop – Approx. 30,953square feet for ten casita units

Containment: Below-grade Darco tank system,nine 18,000-gallon and eight16,000-gallon.

Annual quantitycollected: 250,053 gallons

Water usage: Landscape irrigation

Equipment involved: Pumps – Grundfos SQEsubmersible pumpCistern level controls – Digitalwater quality indicating systemPressure tank – Not availableFilters – Inline convenience filter,Graf Universal large scale filtersystem

Contact: A Desert Rain System by TheHydro Group, Santa Fe,New Mexicowww.thehydrosgroup.com

Commercial Rainwater Harvesting Systems

CABELL BRAND STORE—RECREATIONAL FACILITY

Cabell Brand’s system is locatedin Salem, Virginia. The buildingwas constructed in the 1960s andis used as a recreational facility.The building houses a full tenniscourt, a basketball court, show-ers, weight room, and is adjacentto a swimming pool. The guttersystem was redesigned to carryall the roof water inside thebuilding to the roof washers.

Mr. Brand was experiencing$600 per month water bills from EDCRAWFO

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The two cisterns located at theback of the building, with the threeroof washers above the tanks

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122 | Design for Water

the municipal water supply tooperate the gym and pool. Thepool is open year round. Thegoal was to reduce the water costby 70 percent. After installingthe system the water bill hasbeen reduced by 65-75 percent.The remaining cost for water ismostly due to use in the building.

All of the rainwater from thebuilding is filtered and stored inthe 10,000 gallon tanks. Anyoverflow from the tanks is usedto recharge the ground waterthrough gravel and black fill pipe.

Mr. Brand has used the systemas a model to show local, state, andfederal elected officials how tomanage stormwater by rainwaterharvesting, while also reducing hiscosts for municipal water supply.The end result was the elimina-tion of 6,000 gallons of runoffper 1 inch of rainfall. The esti-mated cost of the system is $30,000.

Location: Salem, Virginia

Type of system: Active rooftop

Year installed: 2003

Annual rainfall: 42 inches

Catchment area: Rooftop – 10,000 square feet,metal building constructed in late1960s

Containment: Two 10,000-gallon aboveground, black, UV-protected tanks

Annual quantitycollected: 252,000 gallons

Water usage: Landscape irrigation and poolreplenishment (potable system)

Equipment involved: Pumps – Jet pumpCistern level controls – FloatswitchesPressure tank – Not availableFilters – Three roof washers,floating cistern filter in one tank,in-line sediment filter, in-linecarbon filter, and a UV light

Contact: Rainwater ManagementSolutions, Salem, Virginiawww.rainwatermanagement.com

EGGLESTON LAUNDRY—NON-PROFIT ORGANIZATION

The Eggleston Services, a non-profit organization in Norfolk,Virginia, is dedicated to provid-ing work opportunities forpeople with severe disabilities.The rainwater catchment systemis integrated into the 34,000 sq.ft. laundry facility in an effort toreduce cost of water, energy, andchemicals. The rainwater ischanneled from the all-rubberroof into a network of drain-pipes in the ceiling to the two10,000-gallon polyethylene tanks

located at the back of the facility.The rainwater is maintained inthe storage tanks at an ambienttemperature of 82 degrees, thusreducing the energy required toheat the washing water.

The rainwater is pumpedout of the tanks with a floatingcistern filter and through threeseparate filtration systemsinto the laundry building whereit is used as washing water.The water is used for washingmachines instead of using

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municipal water from the Cityof Norfolk. The company con-ducts services for 4.5 millionpounds of laundry per year. Byusing rainwater, the center hasexperienced multiple savingsin reduced soap and softenersbecause the rainwater is alreadysoft and in energy saving as lessheat is required in the washingprocess because of the storedtemperature of the rainwater.

To help with the waterheating, the company added a30-foot-long heat exchanger

system; the heat from the washtunnel waste water will now beused to warm the domesticwater or rainwater entering thebuilding. The rainwater system isan automated system switchingfrom rainwater to municipalwater when rainwater is notavailable. Rainwater is addition-ally fed into the boilers topartially fuel the steam-heatedironers. The harvested rainwaterprovides up to 15 percent of thelaundry’s water requirements.Based on the average rainfall, the

Case Studies | 123

Location: Norfolk, Virginia

Type of system: Active rooftop

Year installed: 2002

Annual rainfall: Approx. 40 inches

Catchment area: Rooftop – 34,000 square feet

Containment: Two above-grade 10,000-gallonpolyethylene tanks

Annual quantitycollected: 897,600 gallons

Water usage: Washing machine water

Equipment involved: Pumps – Jet pump, automaticswitch to municipal water ifcistern is dryCistern level controls – Floatswitches and level sensorPressure tank – YesFilters – Floating cistern filter inone tank, bag filter, in-linesediment filter, in-line carbonfilter, and a UV light

Contact: Rainwater ManagementSolutions, Salem, Virginiawww.rainwatermanagement.com

Two rainwatertanks

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Front of theEggleston Servicesbuilding

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system yields seventy-two daysof laundry operation. Theapproximate cost of the system

was $30,000 and the return onthe rainwater harvesting systemwas12 months.

124 | Design for Water

EL MONTE SAGRADO—LIVING RESORT AND SPA

The El Monte Sagrado LivingResort and Spa is a 4-acre luxuryresort nestled into the Taos historicurban downtown. The site takesits architectural craftsmanship

details from the area’s NativeAmerican roots and incorporateslocal building materials, as well asusing green building techniquesto create innovative, cutting-

Location: Taos, New Mexico

Type of system: Active rooftop and stormwatersystem

Year installed: 2003

Annual rainfall: 12 inches rain and 35 inchessnow

Catchment area: Four acresRooftop – 70,189 square feetGround level – 210,000 squarefeet

Containment: Below-grade; two 13,000-gallontanks for a total water storageof 26,000 gallons

Annual quantitycollected: Approx. 1.9 million gallons

Water usage: Landscape irrigation

Equipment involved: Pumps – Lift station pumps,pond circulation pumps, and rain-water pumps (Grundfos)Cistern level controls – Multiplefloat switchesPressure tank – 200 gallonFilters – Sediment and micron

Contact: Developer – Thomas Worrell Jr.,Living Designs GroupArchitect and RainwaterConsultantswww.elmontesagrado.comwww.livingdesignsgroup.com

DOUGLASPA

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TOP:Trout pond construction

BOTTOM:Cascade construction

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Case Studies | 125

Historic acequia, orirrigation ditch, runsalong the perimeter ofthe site. Runoff fromthe spa and four adja-cent guest suites arechanneled to the ditchD

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Upstream bridge crossesthe cascading water

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LEFT:Downstream bridgecrosses below asmaller cascadeRIGHT:Stormwaterponds

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edge technologies. Thirty percentof the complex is exothermallyheated and cooled. The remain-ing portion of the site’s facilitiesrelies on energy produced throughphotovoltaic solar panels. Virtuallyall wastewater is recycledthrough a purification systemcalled the Living Machine and isused for landscape irrigation.

Rainwater is collected, filtered,and used in the spa, and storm-water is collected and used toreplenish ponds and waterfalls.The complex includes a 30,000

square-foot main building, 36grouped guest suites, and 12casitas. The key system compo-nents are collection, filtration,subsurface conveyance, liftstation, rock sediment prefilter,storage, treatment (Tidal WetlandLiving Machine), display ponds,and site irrigation. The rainwatercollection and reuse costs wereapproximately $190,000.

The goal for the eco-resort isto be self-sufficient within fiveyears; the resort is currentlyLEED Certified.

126 | Design for Water

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Living Machinebioreactor

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Stream nextto building

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The 31-acre Earth Rangers sitelocated in Woodbridge northof Toronto, Canada is a show-case of sustainable designtechniques ranging from an8,800 square-foot permeableparking lot to its 100 percentradiant-heated and cooled con-crete floors and ceilings to its

rainwater harvesting system.The Earth Rangers Center iscapable of entertaining over100,000 human visitors yearly,as well as capable of treatingand rehabilitating 5,000 animalsannually. The center is one ofthe most advanced wildlife hos-pitals in the world.

Case Studies | 127

EARTH RANGERS HEADQUARTERS—ANIMAL REHABILITATION CENTER

Location: Woodbridge, Canada

Type of system: Active rooftop

Year installed: 2004

Annual rainfall: 32.2 in.

Catchment area: Rooftop – 62,350 square feetGround level – permeableparking lot

Containment: Below-grade 84,535-gallonconcrete cistern and an 8,000-gallon ZENON tank

Annual quantitycollected: 1.1 million gallons

Water usage: Non-potable uses such as clean-ing, washing floors, and pondreplenishment

Equipment involved: Pumps – Not availableCistern level controls – NotavailablePressure tank – Not availableFilters – ZENON wastewatertreatment system

Contact: Earth Rangerswww.earthrangers.cawww.zenon.com

PHILRUHL,E

ARTHRANGERS

TOP:The 84,535-gallon below-grade rainwater cisternunder constructionBOTTOM:Conceptual rainwaterprocessing

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The water used on site canbe classified in several ways.Potable water requirements aresupplied from an on-site well.Other water needs are met bycombining treated wastewaterand captured rainwater. On-sitewastewater is treated to tertiarylevels using a ZENON membranebioreactor and UV-light sterili-zation. The ZENON membranebioreactor treats the sanitarywastewater on-site; the water isthen drawn back into the build-ing where it is mixed withrainwater. The combined watersupplies are stored in a 79,252

gallon reservoir from which thewater is used for the facility’surinals, toilets, animal ponds,irrigation, and floor/cage washing.

Occasionally the systemreaches capacity of its reservoirand overflows into a small swale.The swale, in turn, goes to theHumber River tributary. Waterquality of the system must behigh to guarantee that theseevents do not pollute the riverenvironments. Rainwater is alsoused for fire protection.Rainwater is harvested from therooftop and stored in a buried84,535-gallon concrete tank.

128 | Design for Water

GRAND PRAIRIE ANIMAL SHELTER—PRAIRIE PAWS ADOPTION CENTER

The Prairie Paws Adoption Center(PPAC) is a 15,000 square-footmunicipal animal shelter forthe City of Grand Prairie, Texasand houses the Animal ServicesDivision. Construction began in2002 and building was complet-ed in October 2003. Total designand construction came in at $3.5million. Land costs were not anissue because PPAC was builtwithin the boundaries of 171acres of city land.

The cistern was not a partof the original design for thePPAC, but was part of a mid-construction attempt to makethe building and grounds a sitefor environmental education aswell as pet adoptions. Schrickel,Rollins and Associates, Inc. wereresponsible for the cistern and

landscape design, although theidea was the result of a visit bythe Environmental ServicesDirector to a McKinney PublicElementary school. McKinneyschools are built with conserva-tion in mind and have severalenvironmental- education ideasincorporated into their design.The cistern and equilibriumtube are their ideas.

The courtyard gutters aremade from aluminum and col-lect rainwater from roughly halfof the roof surface. The buildingis U-shaped, with the connectingroof clad in metal for aestheticreasons. The gutters feed into anaqueduct that connects to thecistern. The cistern was installedabove grade and has a copperplate attached to the exterior

Location: Grand Prairie, Texas

Type of system: Active rooftop

Year installed: 2003

Annual rainfall: Approx. 33 inches

Catchment area: Rooftop – 7,500 square feet

Containment: Above-grade 15,000-gallonfiberglass

Annual quantitycollected: 138,848 gallons

Water usage: Washing machine water

Equipment involved: Pumps – Landscape irrigation sizeCistern level controls –Equilibrium tube in buildingPressure tank – NoneFilters – Not available

Contact: Grand Prairie Animal ShelterSchrickel, Rollins and Associateswww.gptx.org

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Case Studies | 129

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Front of the animalshelter with the entryrainwater tank

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Aqueductover entry

ELIZABETHM

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Animal shelter courtyardwith aqueduct in back-ground

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130 | Design for Water

JENNIFERVUITEL,A

NIM

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RVICESM

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JENNIFERVUITEL,A

NIM

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RVICESM

ANAGER

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LEFT:Equilibrium tube in thebuilding, used to showthe depth of water inthe rainwater tank

RIGHT:Equilibriumtube sign

Aqueductand cistern

Grand PrairieAnimal Shelter

cistern schematic

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with a quote from BenjaminFranklin, “When the well is dry,we know the worth of water.”

The cistern is fiberglass(manufactured by L.F.Manufacturing, Inc.) and is cladin split-face slump block. It isconnected to the courtyardsprinkler system through a smallpump. The irrigation system hasa municipal backup fill for thetank if no rainwater is available.The cistern can hold 15,000gallons of rainwater, and has anoverflow on the west side that

flows into a storm drain. Wateralso backs up and out of theaqueduct when the water flowinto the cistern exceeds thecapacity of the overflow pipe.

The cistern includes a smallPVC pipe, which is buried beneaththe courtyard and connects to anequilibrium tube in the lobby.The tube shows the water levelin the cistern. Unfortunately, thisconnection has proven to be theAchilles heel of the whole systemas it has broken twice, leading tothe draining of the cistern.

Case Studies | 131

LADY BIRD JOHNSON—WILDFLOWER CENTER

The Lady Bird JohnsonWildflowerCenter located in Austin, Texasmakes rainwater collection animportant component of theCenter’s operations. Rainwatercollection has been a part of theCenter’s mission since its estab-lishment in 1982. The Center’s

rainwater collection system hasbeen incorporated into the facil-ities, architecture starting withthe white rock clad, 6,000-gallonEntry Cistern and aqueduct thatescorts visitors into the Center’scourtyard. Rooftop rainwater isdelivered to the Entry Cistern via

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LEFT:Aqueduct toEntry CisternRIGHT:Entry Cistern

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the aqueduct. A second cistern—the 10,000-gallon Tower Cistern—is also made from local whiterock. However, only the walls ofthe tower are rock—the cisternitself is located below grade. Rain-water entering the Tower Cisternis delivered to the upper levels ofthe tower and is allowed to fallto the floor of the tower where afloor grate directs the water into

the cistern. A third smaller cis-tern is located at the Little House.

The Little House Cistern is anindependent system, storing rain-water for that area of the Center.The Entry Cistern is an end-of-the-line collection system that isconnected to a drip irrigationsystem that provides water to thevisitor parking and drop-off arealandscape. The Tower Cistern and

132 | Design for Water

Location: Austin, Texas

Type of system: Active rooftop

Year installed: 1982

Annual rainfall: 30 inches

Catchment area: Rooftop – 18,839 square feet

Containment: Above- and below-grade,70,000 gallons in metal androck tanks

Annual quantitycollected: 333,096 gallons

Water usage: Landscape irrigation

Equipment involved: Pumps – Lift pump and a high-velocity well pump in thestorage tanksCistern level controls – Manualgate valve and gravity flow tothe lift stationPressure tank – Approx. 75 to100 gallonsFilters – Wire mesh debris filterwhere rainwater enters thecisterns

Contact: Lady Bird Johnson WildflowerCenterwww.wildflower.org/?nd=rainwater

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TOP LEFT:Tower CisternTOP RIGHT:

Little House 2,500-gallon cisternBOTTOM LEFT:Butterfly roof

on one buildingBOTTOM RIGHT:

Gutter from metal rooftransporting rainwaterover walkway to anopen-air cistern inlet H

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the remaining Center’s rooftopgutter collection system aredirected through undergroundpipes to an underground lifttank at the northern edge of thebuilding complex.

Pumps lift the collected rain-water into two 25,000-gallon tanks.

These two storage tanks are con-nected to the Center’s irrigationsystem, and are designed tooverflow, if needed, to the adja-cent landscape. The entire LadyBird Johnson Wildflower Centerrainwater system cost is estimat-ed at $250,000.

Case Studies | 133

LADYBIRDJO

HNSO

NW

ILDFLOWERCENTER

LEFT: Funnel collectiondevice

SOURCE: ADAPTED FROM THE LADY BIRD JOHNSON

WILDFLOWER CENTER SITE PLANRainwater harvestingsystem schematic forthe Lady Bird JohnsonWildflower Center

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RIGHT: Metal roof oncommercial building dropsrainwater to a metalcanopy over windows anddoors, which in turn allowsrainwater to collect in steelgutter next to building wall

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In 1917 Henry Ford purchased1,100 acres of Dearborn,Michigan marshland along thebanks of the Rouge River, landthat was considered unsuitablefor farming. Ford quickly trans-formed the site into a ground-breaking mass productionvehicle factory. The factory, sim-ply known as “the Rouge,” wasfamous for providing a brighter,safer, and more efficient factorythan other factories of the day.In 2000, the Ford MotorCompany began revitalizationof the Rouge Factory. The proj-ect—600 acres (the remainingacreage was sold)—was classifiedas the largest Brownfield rede-velopment in American History.

Among many aspects thatwere upgraded for the redevel-opment site was the management

of stormwater leaving the site.Today, a green roof—atop thenew truck assembly plant—and a large porous-pavementparking lot help cleanse thestormwater before it leaves thesite to join the adjacent RougeRiver. This natural treatmentsystem saved—at one-third thecost—millions of dollars byeliminating the need to buildand operate a traditionalstormwater treatment plant.41

The green roof, a 10.4-acreXero Flor

TM

system, consistsof sedum plantings of “FuldaGlow” and “Diffusum,” and 1inch of growing medium, with a2-inch fleece and drainage layer.It has a total saturated weight of10 lbs/sq. ft.

The 19-acre porous parkinglot was, when it was built, the

134 | Design for Water

Industrial Rainwater Harvesting Systems

FORD MOTOR COMPANY—FORD ROUGE CENTER

Location: Dearborn, Michigan

Type of system: Active rooftop and passive 600-acre stormwater system

Year installed: 2000

Annual rainfall: 31.2 inches

Catchment area: Rooftop – 32,000 square-footVisitor Center rooftop collection

Containment: Above-grade 12,500-galloncistern

Annual quantitycollected: 560,102 gallons

Water usage: Irrigation and toilet flushing atthe Visitor Center and filtering ofstormwater through porouspavement

Equipment involved: Pumps – Two at the Visitor CenterCistern level controls – Two-stage level switch Meroid Series500 float switch; digital controlpanel with low-volume alarmPressure tank – 80 gallons andtwo booster pumpsFilters – Ten-inch roof drainpasses through a 10-inch strainerprior to entering tank, 10-micronfinal filter with automaticswitchover

Contact: Ford Motor Company,Environmental Quality Officeand ARCADISwww.ford.comwww.arcadis-us.com

FORDM

OTORCOMPA

NY

Aerial of facility, VisitorCenter on far left of

photograph

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Case Studies | 135

FORDM

OTORCOMPA

NY

FORDM

OTORCOMPA

NY

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OM

THEFO

RDVISITORCENTERPLANS

FORDM

OTORCOMPA

NY

TOP:Green roof over assembly buildingLEFT:Rouge Visitor Center rainwatertank, inside the building for display.BOTTOM LEFT:Porous parking lot after completionin 2003BOTTOM RIGHT:Ford Motor Company VisitorCenter rainwater tank schematic

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largest porous parking lot in theworld.

42

The porous nature ofthe pavement allows rain andsnow to seep into undergroundrock storage basins, therebyfiltering the water before it isdirected to the natural treatmentwetlands for further filtering.The pavement can store 3.6million gallons. Four Archimedes-screw pumps move the storm-water when needed. The naturalstormwater managementsystem significantly reduces the

amount of stormwater leavingthe site.

Rooftop rainwater harvest-ing is conducted at the VisitorCenter only. This facility hasbeen certified as a LEED Goldbuilding. At the 32,000 square-foot Visitor Center, rainwaterfalling on the roof is collectedand stored in a 12,500-galloncistern. The collected water isfiltered and used for the Center’ssurrounding landscape and thefacility’s toilets.

136 | Design for Water

TOYOTA MOTOR SALES, USA INC.—TOYOTA LOGISTICS SERVICE,PORT OF PORTLAND VEHICLE DISTRIBUTION CENTER

In following with Toyota MotorSales’ Global Earth Charter and“Process Green” initiative, the86.4-acre Portland VehicleDistribution Center (VDC) wasrelocated and expanded whileincorporating the USGBC LEEDsustainable building considera-

tions. Toyota’s efforts wereawarded with LEED Gold fornew construction in 2005 forthis new facility. Among themultiple design componentsselected for installation were abioswale along the waterfront tofilter parking lot runoff water,

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Toyota Facilityentry

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and a rainwater harvesting sys-tem that would replaceseventy-six percent of the build-ing’s potable water supply.

The new rainwater harvest-ing system supplies nearly 90percent of the toilet and urinalwater used in one year. Additionalwater is saved by washing onlythe new vehicles arriving by shipthat are equipped with exteriorinstallations—such as graphicsand spoilers—instead of washingall vehicles as previously prac-ticed. Approximately 1,000

vehicles are processed daily, or270,000 annually.

The rainwater is collectedfrom one-half of the main build-ing rooftop—approximately33,500 square feet—because of theslope of the roof and the locationof the cistern. The rainwaterdrains to the adjacent below-grade fiberglass tank through a6-inch by 8-inch metal gutter to a4-inch downspout and polyvinylchloride (PVC) and copper pipes.Once in the tank a FamilianNorthwest H2O FloPro moni-

Case Studies | 137

Location: Portland, Oregon

Type of system: Active rooftop and passivestormwater system

Year installed: 2005

Annual rainfall: 36.6 inches

Catchment area: Rooftop – Half of the mainbuilding, approximately 33,500square feet

Containment: Below-grade, 6,000-gallon fiber-glass cistern

Annual quantitycollected: 757,699 gallons

Water usage: Flushing of ten toilets and threeurinals, 120,000 gallons

Equipment involved: Pumps – Myers WHR sumppump in tankCistern level controls –Electronic, digitalPressure tank – Proflo byAMTROL, 100 psi, 32 gallonAquaBoost Controller and G&L(Gould) pumpFilters – 5-micron bag filter,model PE5G1S by PentekFiltration (changed every month)

Contact: Toyota Motor Sales USA, Inc.www.toyota.com

DOUGW

ARNEKE,T

OYOTA

MOTORSA

LES,USA

INC.

Rainwater 6,000gallon tank priorto installation

DOUGW

ARNEKE,T

OYOTA

MOTORSA

LES,USA

INC.

Rainwater tankinstallation

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138 | Design for Water

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LEFT:Back of house gutter

and downspoutsRIGHT:

Mixing tank wheremunicipal water isadded if rainwaterquantity is insuffi-

cient; with pump andpressure tank

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LEFTMunicipalwater fillRIGHT:

Rainwatercontrols

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EXISTINGSYSTEM

Rainwater processingschematic

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toring system controls the Gould(G&L) pump that raises the har-vested rainwater to a 200-gallonmixing tank. At this point, if nowater is in the cistern, municipalwater is turned on to allow thesystem to operate.

The system generates aboutsix times the amount of waterused to flush the toilets. Theexcess goes into the stormwaterdrain. Toyota is expanding the

main building, and will considerusing the excess to flush addi-tional toilets added in theexpansion. The estimated costsof the system is approx. $36,800,plus fees and permits.

At ground level, the 86.4-acrenatural stormwater treatment isa bioswale adjacent to theWillamette River that filters thestormwater prior to it infiltrat-ing or entering the river flow.

Case Studies | 139

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AMERICAN HONDA NORTHWEST REGIONAL FACILITY

This American Honda NorthwestRegional Facility located inGresham, Oregon is a multi-usefacility which includes adminis-trative offices, parts distributionwarehouse, automotive technicaltraining, service center, and autosales. American Honda’s worktoward environmentally sensitiveand fuel efficient productsinspired them to apply for theUSGBC LEED-NC certificationprogram for which it received aGold rating. Starting with thisrating system, Honda identifiedevery green building require-ment in an attempt to use valueengineering and life cycle analy-sis to decided on specific, desiredfeatures. Rainwater harvestingfor use in the plumbing system,for watering landscaping, andfor a natural stormwater remedi-ation process, were among thefeatures selected for the new site.

Rainwater is collected fromthe eastern half of the warehouse

roof approximately 135,000 totalsquare feet in size. The water isgravity fed via downspouts intoa 90,000-gallon below-gradeconcrete storage tank located onthe eastern edge of the property.The stored rainwater is pumpedout by a submerged transferpump into the facility waterreclamation room where it makesits way through two water filtersand an Ultraviolet Light (UV)for sterilization. The rainwater isthen stored in two 300-gallonmixing tanks until needed. Thisstored water is not consideredpotable by the building systemand occupants. As it is needed,the treated water is movedthrough the plumbing systemwith the aid of a booster pumpand one pressure tank. The rain-water is initially used to flush thefacility’s 16 toilets and urinals.

A secondary use of the cap-tured rainwater is the landscapingimmediately adjacent to the

Location: Gresham, Oregon

Type of system: Active rooftop and passivestormwater system

Year installed: 2001

Annual rainfall: 36.6 inches

Catchment area: Rooftop – 135,000 square-footwarehouse rooftop collection;annual mandatory flushing offire suppression system is directedto the tank during the dry season

Containment: Below-grade, 90,000-gallonconcrete cistern

Annual quantitycollected: 2.8 million gallons

Water usage: Ten toilets and six urinals pluslandscape irrigation

Equipment involved: Pumps – SubmersibleCistern level controls – Electroniclevel sensorStorage tanks – Two 300-gallontanksFilters – Aqua Pure Filter (changedquarterly) and a UV Light

Contact: American Honda NorthwestRegional FacilityDesigned by System DesignConsultants, Portland, Oregon

Bag filter and used filter to the side

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140 | Design for Water

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Front of theHonda Facility

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Landscape on east endof the building, wherethe rainwater tank is

buried and tank accesshatch is located

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Interior courtyardirrigated with

captured rainwater

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Case Studies | 141

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LEFT:Roof drainsinside buildingRIGHT:Filters

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LEFT:Mixing tanksRIGHT:Pressure tanks

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Stormwater runoff pond

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building, which is watered withthe rainwater. A drip irrigationsystem is used to water newplantings until they are estab-lished, and at that point thesystem is turned off. The irriga-tion system can be turned backon during a drought if needed.

If the underground storagetank runs out of water, a domesticwater line which drains into the300-gallon tanks takes over andsupplies water used for flushingthe toilets and landscape irriga-tion. In addition to rainwater,the underground tank is alsosupplied with approximately40,000 gallons of water that ispumped through the facility fire

suppression system during itsannual flow test. AmericanHonda schedules the flow testfor late summer, the normal drytime of year. In most otherfacilities this water is drainedinto the storm or sewer system.

Any overflow from theunderground tank, along withstormwater runoff from else-where on the property, isdirected to the onsite retentionpond for filtration. This smallpond has a culvert that leadsinto a separator tank whereimpurities are held and removedby a local hazardous materialshandling service before they canenter the city storm drain system.

142 | Design for Water

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CILITY

Rainwater processingschematic

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Similar to the Kitt PeakObservatory discussed later, theKilauea Military Camp (KMC)has only one water source, rain-water. KMC, located on the bigisland of Hawaii, occupies about50 acres of the 300,000-plus acreHawai’i Volcanoes NationalPark. It began as an idea of HiloBoard of Trade members for atraining ground for the NationalGuard and a vacation or resortlocation for the Army. The sitehas served as a training grounds,a Navy camp, has hosted num-

erous dignitaries, and brieflyserved as a prisoner-of-warcamp during World War II. Theadjacent Kilauea volcano is oneof the most active volcanoes inthe world, last erupting in 1983.

The KMC rainwater systembasically consists of two divisions—the four raw water tanks (three450,000-gallon and one 250,000-gallon) and the three finishingwater tanks (one 250,000-gallon,one 350,000 gallon, and one450,000 gallon). In total with thevarious other tanks the KMC has

Case Studies | 143

Location: Big Island of Hawaii

Type of system: Active rooftop rainwater catchment

Year installed: 1916

Annual rainfall: 40.7 inches

Catchment area: Rooftop and catchment fieldstotaling 6.5 acres

Containment: Above grade, 19 welded steeltanks with a total capacity of 3million gallons; tanks range insize from 250,000 to 450,000gallons

Annual quantitycollected: Approximately 11.5 million gallons

Water usage: All water needs both potable andnon-potable

Equipment involved: Pumps – LargeCistern level controls – ElectronicPressure tank – Gravity flow topoint of useFilters – rapid sand and chlorina-tion after sand filtration

Contact: Purell Water Specialty Companymanages systemwww.kmc-volcano.com

TRISHAM

ACOMBER,U

NIVERSITYOFHAWAII

TOP:KMC Entry signBOTTOM:Collection surface

TRISHAM

ACOMBER,U

NIVERSITYOFHAWAII

KILAUEA MILITARY CAMP—HAWAI’I VOLCANOES NATIONAL PARK

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144 | Design for Water

TRISHAM

ACOMBER,U

NIVERSITYOFHAWAII

LEFT:Catchment surface

collection pipeRIGHT:

Flume from catch-ment surface

to storage tank TRISHAM

ACOMBER,U

NIVERSITYOFHAWAII

TRISHAM

ACOMBER,U

NIVERSITYOFHAWAII

Sandfilters

TRISHAM

ACOMBER,U

NIVERSITYOFHAWAII

Water storagetanks

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19 tanks, used for a total waterstorage capacity of 3 milliongallons. All water needs aresatisfied, with the rainwatercatchment system totaling 25,000gallons to 30,000 gallons per day.

They have built additionalroof-like catchment fields toincrease runoff catchment. Intotal there is 6.5 acres of roofsurface catching rainwater. Once

the rainwater is caught it is heldin the raw water tanks until it isdirected through the rapid sandfiltration at 180 gallons perminute. The purification processis completed with a chlorinationtreatment. Once purified, therainwater is pumped up to thehigher finishing- water tanksand gravity feeds the variousbuildings on site.

Case Studies | 145

School Rainwater Harvesting Systems

ST. MICHAEL’S PARISH DAY SCHOOL—STUDENT CENTER

The St. Michael Parish DaySchool Student Center is amulti-use facility. It was builtto accommodate assembly uses,performance activities, chapelfunctions, and physical educa-tion activities. The StudentCenter was designed and builtwith an integral rainwater catch-ment system. Each corner of theCenter contains a 7,000-gallon

cistern. The cisterns are madefrom corrugated galvanizedpipes stood on end coatedwith smooth concrete to createviable storage. The cisterns areapproximately 10 feet in diame-ter by 14 feet tall. The roof ofthe Center drains by gravityto these four cisterns, threeof which drain to the fourththat contains a deeper bottom

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Entry signagefor the school

Location: Tucson, Arizona

Type of system: Active rooftop

Year installed: 2000

Annual rainfall: 12 inches

Catchment area: Rooftop – 10,000 square feet

Containment: Above-grade, four 7,000-gallongalvanized metal tanks

Annual quantitycollected: 67,320 gallons

Water usage: Landscape irrigation

Equipment involved: Pumps – 1-horsepower Telell4RJ38Cistern level controls – NotavailablePressure tank – Telell variable5P22Filters – Pool type

Contact: Architect – Vint & AssociatesRainwater consultant: RichardBrittain, University of Arizonawww.stmichael.net

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146 | Design for Water

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LEFT:Outside viewof one tank

RIGHT:Interior view of thesump tank— the

deepest, and where theother three tanks drain H

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View of a secondtank from the coveredwalkway leading to

the building

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Pump andother equipment

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elevation to allow a sump, wherethe rainwater is ultimatelypumped from to supply thelandscape irrigation. A pumpand equipment room locatedbehind the scoreboard containsthe equipment to run the sys-tem. The costs of the system,including building and furnish-ings, were $1.5 million.

Case Studies | 147

PressuretankH

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ROY LEE WALKER—ELEMENTARY SCHOOL

TheMcKinney Independent SchoolDistrict (ISD) was chosen in 1998by the Texas State Energy Conser-vation Office to split a $400,000grant with the Austin ISD. Thegrant was to be used to buildsustainable schools. TheMcKinneyISD used the grant money to helppay for the design and building ofRoy LeeWalker Elementary Schooland the Austin ISD used themoneyto assist with the J.J. Pickle

Elementary School. Both schoolsare pioneering the use of sustain-able building features such asnatural day lighting, rainwaterharvesting, and natural and nativematerials in educational settings.

The Roy Lee WalkerElementary School plan has beenused for three additional schoolsowing to its principles of sus-tainability and demonstrateddramatic impact on attitudes,

Location: McKinney, Texas

Type of system: Active rooftopYear installed: 2000Annual rainfall: 33.7 inchesCatchment area: Rooftop – 69,788 square feetContainment: Above-grade, six tanks with a

combined storage of 68,000gallons

Annual quantitycollected: Approx. 1.3 million gallonsWater Usage: Landscape irrigationEquipment involved: Pumps – One 300 gallon-per-

minute circulation pump fornon-freezing events, plus onewell pumpCistern level controls –Mechanical float switch with ahigh and low level to keep tankfrom filling too much withdomestic waterPressure tank – NoneFilters – Utilize chlorine and uraticacid for potential algae growth

Contact: Architect – SHW GroupArchitects, TexasRainwater Consultant –Innovative Design, North Carolinawww.innovativedesign.net

INNOVATIVEDESIGN,INC.

View of the front of the school,the windmill and two cisterns

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148 | Design for Water

INNOVATIVEDESIGN,INC.

Gutter connectionthrough a pipe tothe front cistern

INNOVATIVEDESIGN,INC.

View of cistern at theback of the schoolfrom the courtyard

INNOVATIVEDESIGN,INC.

View of the courtyardand its sustainable

components

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reduced teacher absenteeism, andthe students’ raised interests inthe sciences. The blending of thebuilding’s physical environmentand the students learning processhas greatly paid off, as thebuilding’s design contributes tostudent educational experiences.

One educational componentat the school is the rainwaterharvesting system. Six cisterns—combined storage of 68,000 gallonsstrategically placed around theschool—capture rain falling onthe school roof. Each cistern hasan individual filtration systemfor filtering debris that may col-lect off the roof. The school haswon an award—AmericanInstitute of Architects Top Tenlist for most EnvironmentallyResponsible Design Projects in

the Nation. The cost of theSchool facility and furnishingscame in at approximately $10.8million (the same plans havenow been used four times, there-by reducing this initial cost).

Case Studies | 149

INNOVATIVEDESIGN,INC.

Window into equip-ment room forkids to see howeverything works

Pipes inside theschool allow kids tosee how the tanks filland empty as water isused and receivedduring rainstorms

INNOVATIVEDESIGN,INC.

HERITAGE MIDDLE SCHOOL—WAKE COUNTY SCHOOLS

The Heritage Middle Schoolin Raleigh, North Carolina hasbeen recognized several timesfor its sustainable and innovativedesign features. First, the USEnvironmental Protection

Agency recognized the schoolas an SEDI building, a buildingdesigned to earn the EnergyStar rating. Then, the schoolwas awarded the “School ofExcellence” for 2004 by the state

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of North Carolina. The schoolwas also named as one of thetop 25 Most Improved K-8Schools in North Carolina.The school system has beenpromoting sustainable designthrough the use of Triangle JCouncil of Government’s HighPerformance Guidelines, a local-ly modified version of the LEEDrating system.

One of the nine sustainablecomponents built into theschool facility is a rainwater col-lection system. Rain that falls onthe school’s roof is collected inone of the five underground cis-terns. The total rainwater storagecapacity at the school is 125,000gallons. Prior to going to thetoilets, the water is treated withchlorine to about 1/20 the levelrequired for potable use. A gaugeand graphics explaining the sys-tem are displayed in the mainentrance to enhance student’sappreciation of the impact andimportance of the system. Alltoilet fixtures and classroom sinkfaucets are low-flow and faucetshave automatic shutoff. Thecaptured rainwater is also used

to irrigate the school’s adjacentfootball field.

The air-cooled chillers save700,000 gallons of water annuallyover the use of a chiller utilizinga cooling tower. Approximately1,515,000 gallons of water areused indoors per year, 65,000gallons of potable water usedoutdoors per year, and no waste-water is reused onsite.

To avoid lawn watering andmowing, over an acre and a halfof the site has been modifiedfrom grass to more natural andmulched areas, with regionallyappropriate plantings. WCPSSrequired drought-resistant, low-maintenance grass for lawnareas. They will not irrigate thelawns. However, to address thegrowing problems associatedwith stormwater runoff andnitrogen that eventually flow tothe Neuse River, the school hasbuilt approximately one acre ofconstructed wetlands. The wet-lands were also designed to serveas an outdoor learning center.Walkways lead from the schoolto a boardwalk crossing over thewater to an island in the center

150 | Design for Water

Location: Raleigh, North Carolina

Type of system: Active rooftop

Year installed: 2004

Annual rainfall: 34 inches

Catchment area: Rooftop – rooftop collection149,925 square feet

Containment: Five below-grade 25,000-gallontanks with a combined storageof 125,000 gallons

Annual quantitycollected: 2.8 million gallons

Water usage: Flushing of toilets and irrigationof the football field

Equipment involved: Pumps – Submersible MyersRanger 50 gal/min; boosterpump is a Bell and Gossett1531 series rated at 120gal/minCistern level controls – NotavailablePressure tank – Antrol 275Filters – Watts 50-micron WH SS-B

Contact: Architect and rainwaterconsultant – Innovative Design,Inc., North Carolinawww.innovativedesign.net

INNOVATIVEDESIGN,INC.

Front ofschool

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of the wetland and to the water’sedge, allowing the students toeasily reach the fauna. A pathwayon the island allows students toalso study wetland soils. Thesefeatures provide students with theteaching tools to experience andbetter understand how wetlandsare essential to our ecologicalsystems. A photovoltaic panelon the island operates a wateraerator, serving as a teaching

tool as well as preventing thenesting of mosquitoes.

Combined with the rainwatercollection system, the wetlandreduces the amount of nitrogendischarged into the adjacent streamto a level of 85 percent below thenitrogen level discharged fromthe site before the new facilitywas constructed. The estimatedcosts of the School facility andfurnishings is $16 million.

Case Studies | 151

INNOVATIVEDESIGN,INC.

Back ofschool panorama

View with drop-offarea at center

ROBERTA.F

LYNN

PHOTOGRAPHY

LANGSTON HIGH SCHOOL CONTINUATION ANDLANGSTON-BROWN COMMUNITY CENTER

Langston High School is aredevelopment project for acommunity in Arlington,Virginia. The 2.46-acre sitewas originally home to the firstAfrican-American elementaryschool in Arlington. Today, theelementary school has beenreplaced with a larger facility, theLangston High School, whichhas been combined with theLangston-Brown CommunityCenter to meet the recreationalneeds of the County. Theproject was designed with a

“new urbanism” approach, aswell as a goal to reach theefficiency rating of silver bythe USGBC’s LEED program.At completion the building wasthe first building to achieveLEED status (Silver) in thestate of Virginia.

The building has embracednumerous environmentalfeatures including stormwatermanagement, energy savingsabove the ASHRAE standards,maximization of naturaldaylight, recycled materials,

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and assistance with reducingconstruction wastes andincreasing reuse on otherprojects in the County. Thestormwater management forthe project combines perviouspavement, a bio-retentiongarden, and rooftop rainwatercollection to reduce stormwaterflow and improve the site’sstormwater runoff quality.

The bio-retention gardencollects and filters stormwaterrunoff from the imperviousplay/courts area.

The rooftop rainwateris collected from the 16,500square-foot roof in two 24-foottall, 9-foot-diameter 11,000-gallon welded-steel tanks thathave been incorporated intothe facility’s structure.

152 | Design for Water

Location: Arlington, Virginia

Type of system: Passive rooftop

Year installed: 2003

Annual rainfall: Approx. 32.1 inches

Catchment area: Rooftop – 16,500 square feetGround level – bio-retention only

Containment: Above-grade, two 11,000-gallonwelded-steel tanks by ColumbiaTechTank

Annual quantitycollected: 279,134 gallons

Water usage: Landscape irrigation and variousother non-potable water uses

Equipment involved: Pumps – Gravity flowCistern level controls – Liquidlevel indicator with float andtarget boardPressure tank – Not availableFilters – Not available

Contact: Architects – BerryRio Architectureand Interior Design, Springfield,

Virginiawww.beeryrio.comwww.designshare.com

DUANELEMPKE,S

ISSO

NST

UDIOS,IN

C.

Building frontelevation

DUANELEMPKE,S

ISSO

NST

UDIOS,IN

C.

LEFT:West or front of

building tank that isconcealed behindthe white panels

RIGHT:Above-ground rain-water tank at the

back of the building

DUANELEMPKE,S

ISSO

NST

UDIOS,IN

C.

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One cistern is completelyexposed at the back of thebuilding and one cisternis slightly concealed bypanels in the front of thebuilding. Both are meantas “community billboards”for exposing sustainabilitypractices and educatingthe community. Thecollected rainwater is usedfor onsite irrigation,sidewalk washing, andother nonpotable uses.The estimated cost ofthe system is included inthe total building costsof $8.4 million.

Case Studies | 153

Rainwater tankschematic

STEPHEN EPLER RESIDENCE HALL—PORTLAND STATE UNIVERSITY

Stephen Epler Residence Hall islocated at the southwestern cor-ner of Portland State University.

More specifically, the building islocated at the southeast intersec-tion of SW 12th Avenue and

KEVINO’N

EILL,G

EOTK,LLC

LEFT:View of courtyardand runnel thatconnects in-linestormwater plantersRIGHT:Liner that will wrap thecrates is being unfold-ed prior to installation

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SW Montgomery Street inPortland, Oregon. The six-storyEpler Hall is a mixed-use build-ing with five upper floors—130housing units—and one ground-level floor dedicated to officesand classrooms. The buildingwas designed with sustainablecomponents focusing on inte-grating new technologies to getthe greatest benefit from thesite’s wind, rain, and sun charac-teristics. One of the design goalswas to make stormwater manage-ment interesting and engagingfor students and residents ofthe building.

The eastern side of Epler Hallhas been designed as a storm-water courtyard with visiblerainwater movement and filtra-tion features. Rainwater fallingon Epler Hall roof is directed todownspouts that discharge toriver rock splash boxes at groundlevel of the eastern public level

court yard.Water from the splashboxes are directed to flow overand through a 2-foot-wide “run-nel” of widely spaced blocks to astormwater planter. An overflowpipe allows a faster emptying ofthe splash box to the stormwaterplanter if more rain falls thanthe runnels can maintain.

Once the rainwater entersthe stormwater planter it mustinfiltrate through approximately3 feet of soil and gravel to thebottom of the planter. At thebottom of the planter is a 4-inchperforated pipe wrapped in afilter-fabric sock. The rainwateris filtered and ready to be direct-ed through the perforated pipeto a drain pipe that leads to theadjacent Rainstore3 water har-vesting structure. There are foursplash pads with runnels andfive stormwater planters in theEpler Hall courtyard. The storm-water planters are connected to

154 | Design for Water

Location: Portland, Oregon

Type of system: Active rooftop

Year installed: 2003

Annual rainfall: 34.9 inches

Catchment area: Rooftop – 11,760 square-footrooftop of the residence hall

Containment: Below-grade 8,600-gallon cistern,Rainstore3 water harvestingstructure by Invisible Structures Inc.

Annual quantitycollected: 230,000 gallons

Water usage: Five toilets, one urinal, andlandscape irrigation

Equipment involved: Pumps – Goulds high capacity4-inch well pump in a flow inducerCistern level controls – Floatswitch, SJE Rhombus controlssensor float with mercury tilt-switch overrides the pump whenno water is availablePressure tank – Not availableFilters – Sanitron UV Light

Contact: Portland State UniversityFacilities & Planning, Portland,OregonInvisible Structures, Inc.Mithun, Inc., Seattle, WashingtonGeotk, LLC, Vancouver, WAwww.sustain.pdx.eduwww.invisiblestructures.com

LEFT:Locating the crateson top of the linerduring installation

RIGHT:Wrapping the

crates with the liner KEVINO’N

EILL,G

EOTK,LLC

KEVINO’N

EILL,G

EOTK,LLC

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Case Studies | 155

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Downspout torock splash pad

KEVINO’N

EILL,G

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LEFT:Sealing the linerRIGHT:Crates and linerconnection to thesump

KEVINO’N

EILL,G

EOTK,LLC

LEFT:Splash pad box, run-nel, and stormwaterplanterRIGHT:Sign in bathroomabout rainwaterin toilets

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allow overflow from one to thenext, or lower, planter throughsurface runnels. A faster (over-flow) pipe is provided to accept

water to the storage structure ifthe water rises above the 12-inchfreeboard provided in eachplanter.

The filtered rainwater drainsfrom the storage structure to asump where a well pump deliversthe water to the toilets or irriga-tion supply line. Prior to usage,the water is first treated by anultraviolet light filter. An overridepressure switch will not allow thewell pump to operate if the levelis below the 3-foot minimumdepth. A 6-foot level of watercan be attained before a 6-inchover-flow directs the water to anadjacent storm sewer.

This rainwater collectionsystem and other sustainableelements—such as eliminatingair conditioning—reduced themunicipal water demand by700,000 gallons annually. Theproject has been awarded aUSGBC LEED Certified leveland a $15,000 EmergingTechnology Grant from theCity of Portland Office ofSustainability Development’sG/Rated Program.

156 | Design for Water

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TOP:UV filter and otherbuilding equipment

BOTTOM:Rainwater systems

layout in thenarrow courtyard

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Kitt Peak National Observatory(KPNO) is located 56 miles south-west of Tucson, Arizona, off StateRoute 86 on lands leased from theTohono O’odham Nation. The200-acre observatory site includesthe Kitt Peak summit, which is6,875 feet above mean sea level. Inaddition to KPNO, there are ninetenant observatories and onehydrogen alpha mapping centeratop Kitt Peak. All observatoryfacilities at this location (KPNOand tenants) are collectivelyknown as Kitt Peak Observatory,containing the world’s largestcollection of optical telescopes(a total of 22). KPNO is a divi-sion of the National OpticalAstronomy Observatories(NOAO), which is operated bythe Association of Universitiesfor Research in Astronomy, Inc.,

under cooperative agreementwith the National ScienceFoundation (NSF).

During the initial observato-ry construction in 1960, the NSFand KPNO worked together toresolve the lack of potable waterat the new observatory complex;the result was a rainwater har-vesting system consisting of a6-acre catchment area that uti-lizes most of the concave roadsystem and the two main park-ing lots. All rooftops of thecomplex drain to the adjacentroadways. From the roads andparking lots the rainwater isdirected to two concrete catchbasins, which act as an initialfirst-flush device. Combined, theupper and lower basins holdapproximately 600,000 gallons.The rainwater is left in the

Case Studies | 157

Parks and Interpretive Centers Rainwater Harvesting Systems

KITT PEAK OBSERVATORY—TOHONO O’ODHAM INDIAN RESERVATION

Location: Tohono O’odham IndianReservation, Arizona

Type of system: Active rooftop collection andground-level runoff collection,installed due to lack of potablewater service

Year installed: 1960

Annual rainfall: 25 inches

Catchment area: Rooftop and surface – 261,360square feet (6 acres)

Containment: Above-grade, two 500,000-gallon tanks

Annual quantitycollected: 1.2 million gallons annually

Water usage: Potable water source for all uses,3,000 gallons average daily use(no landscape irrigation)

Equipment involved: Pumps – Large, municipal qualityCistern level controls – ElectronicPressure tank – YesFilters – See process below

Contact: Kitt Peak National Observatorywww.noao.edu/kpno

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Kitt Peak fromthe highway

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158 | Design for Water

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Uppercatch basin

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Lowercatch basin

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Backupsupply lake

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basins for one to two days whilesolids settle to the basin bottom.From the basins the rainwater ispumped to a 500-gallon flashmixer and then to a flocculationtank where more solids settleout. The flash mixer adds sodaash and aluminum sulfate tohelp the settling process. Afterthe second settling process, therainwater is pumped through asand filter, then undergoes achlorination process, and finallyis pumped to one of two500,000-gallon steel tanks forstorage. To ensure that there isadequate water for fire suppres-sion, the water supply is neverallowed to go below 200,000 gal-lons. The rainwater is distributedfrom storage after it is chlorinat-ed a second time and pumpedthrough a charcoal filter.

The complex has a backupwater supply, which is a 9-mil-lion-gallon (27 acre-foot) lake 4miles down the road. A 6,000-gallon tanker can haul waterfrom the lake to the main park-

ing lot for release into the uppercatch basin for treatment whenwater supplies are low.

The rainwater harvestingsystem supplies enough waterfor the yearly needs of all resi-dent and visiting astronomers,daytime staff, tenant observato-ries and general public/visitors.There are six houses, fourdorms, two visitor houses, over22 telescopes, maintenance facil-ities, and one visitor center onthe mountain. The human pop-ulation on the mountain consistsof 12 to 15 people 24 hours aday, 60 daytime staff, six to eightastronomers, and up to 300 visi-tors a day, with an average of 50.

Over the last four years theNOAO complex has reduced itsyearly water usage by 500 gallonsby installing low-water-flowdevices. Excessive use of laundryfacilities is discouraged, washingof vehicles is prohibited, and alldumping is forbidden to preventcontamination of the rainwatercatchment areas.

Case Studies | 159

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Two 500,000-gallonstorage tanks

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Carkeek Park EnvironmentalLearning Center was built toprovide the existing facilitymore room for meetings andassembly needs so they couldincrease their environmentaleducation and stewardshipactivities. The building hastwo restrooms with one toiletin each, a small kitchen facility,and a large room for assembly.The building is an example ofenvironmental building tech-niques including:

• Energy–efficient, highly-insulated building envelope,intelligent lighting, andnatural ventilation

• Solar electric (photovoltaic)panels

• Eighty percent recycling orsalvaging of demolition andconstruction materials

160 | Design for Water

CARKEEK PARK—ENVIRONMENTAL LEARNING CENTER

Location: Seattle, Washington

Type of system: Active rooftop

Year installed: 2002

Annual rainfall: Approx. 52 inches

Catchment area: Rooftop – 1,500 square feet

Containment: Above-grade, 4,800-gallon blackpoly tank and two 50-gallonrainbarrels

Annual quantitycollected: 43,421 gallons

Water Usage: Two toilets and landscape irrigation

Equipment involved: Pumps – Exterior in equipmentroom, approx. 1 horsepowerCistern level controls – Floatswitch, electronicPressure tank – Small, approx.2 gallonFilters – Roof washer, 5- and10-micron filters

Contact: Carkeek Park EnvironmentalLearning Centerwww.seattle.gov/PARKS/parkspaces/CarkeekPark/ELC.htm

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Front viewof building

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• Salmon-friendly and drought-tolerant native landscape

• Paint and coatings as well asadhesives and sealants, alongwith wood composite and car-pets, are types that protectindoor air quality

• Salvaged and reused materialsin the new construction ofthe building

• Regional materials used tosupport local economy

• Rooftop rainwater collection

for flushing toilets and man-aging stormwater

The Carkeek Park Environ-mental Learning CenterRainwater Catchment System isvery simple, and is a good examplefor those wanting to implementa system on personal property.Most of the rain that falls on theroof of the building is directed tothe 4,800 gallon tank that is justoutside the entry to the building.The rainwater is filtered with atypical roof washer and is then

Case Studies | 161

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Rainwater tanks androof washer at the sideof the buildingRIGHT:Rainbarrels at the backof the buildingH

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Equipmentroom

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pumped from the tank to servethe building and irrigation needs.The rainwater goes through twofilters and a UV light prior toentering the building. The tworainbarrels are used for land-

scape irrigation with a gravitysystem. The Center providesabundant signage for educatingthe public and has been rewardedfor their work with a USGBCLEED Gold Certification.

162 | Design for Water

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Pressure tank andused filters

CHESAPEAKE BAY FOUNDATION’S PHILIP MERRILL ENVIRONMENTAL CENTER

The Chesapeake BayFoundation’s Philip MerrillEnvironmental Center hasbeen listed as a global environ-mental model that operates inharmony with the land, naturalresources, and the ChesapeakeBay. Their water stewardship iscommendable. There are noflushing toilets in the Center,which helps the Center to use90 percent less water than atypical office building. TheCenter believes that reducingwastewater use means cuttingthe amount of wastewater thatflows to the local sewage treat-ment plant. To decrease waterfurther, the center capturesrooftop rainwater for use in firesuppression, hand washing, mopsinks, the climate control system,

laundry, and washing equip-ment. Using rainwater allowsless groundwater to be with-drawn to feed municipalsystems. Less water leavingthe site also means the Bayand the adjacent Black WalnutCreek stay cleaner. A bioreten-tion cell filters the parking lotstormwater runoff.

The Center’s wood for thesunshades was salvaged fromthe barrels of an old EasternShore pickle plant that wasgoing out of business. Thedurable wood is a local resourcethat would have otherwisegone to waste. Three of thebarrels were used for the rain-water cisterns. Concrete foot-ing forms were made fromreused plywood.

Location: Annapolis, Maryland

Type of system: Active rooftop

Year installed: 2000

Annual rainfall: Approx. 42.2 inches

Catchment area: Rooftop – 17,000 square feet

Containment: Above-grade, three old picklebarrel cisterns 7,000 gallons each

Annual quantitycollected: Approx. 402,461 gallons

Water usage: Nonpotable uses

Equipment involved: Pumps – Not availableCistern level controls – NotavailablePressure tank – Not availableFilters – Sand, charcoal, andchlorine

Contact: Chesapeake Bay Foundationwww.cbf.org/merrillcenter

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Case Studies | 163

LORETTA

JERGENSEN,C

HESA

PEAKEBAYFO

UNDATION

Close up of thepickle barrels usedfor cisterns

LORETTA

JERGENSEN,C

HESA

PEAKEBAYFO

UNDATION

Front of building,with cisterns

CHESA

PEAKEBAYFO

UNDATION

Do-not-drink signin bathrooms

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The Chesapeake BayCenter’s headquarters haswon more than 25 significantawards, including the first

USGBC LEED PlatinumAward in 2001 and theBusiness Week/ArchitecturalRecord Award.

164 | Design for Water

Municipal Rainwater Harvesting Systems

SAN JUAN FIRE STATION NO. 1—RURAL FIRE PROTECTION

The San Juan Fire Station No.1is a typical rural fire depart-ment except that they have arainwater collection systemon their 9,000 square-footbuilding. The three-bay stationhas gutters on all eaves thatlead to a 240-gallon ball tankthat serves as a manifold forthe collection of all roof runoffwater. A small 60-gallon-per-minute one-half-horsepowerpump moves the rainwaterfrom the ball tank to themain tank. Six-inch down-spouts lead to the ball tank,but a 2-inch line transportsthe collected water back to thetank. The 30,000-gallon metal

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Front view offire station

Location: Friday Harbor,Washington

Type of system: Active rooftopYear installed: 2005Annual rainfall: 54.8 inchesCatchment area: Rooftop – 9,000 square feetContainment: Above-grade, 30,000-gallon

metal tank and a 240-gallonball tank

Annual quantitycollected: 276,685 gallonsWater usage: Fire sprinklers and fire fighting

in generalEquipment involved: Pumps – 1/2-horsepower pump

from ball tank to main tankCistern level controls – YesPressure tank – YesFilters – Yes

Contact: Design and installation by TimPope, Friday Harbor, [email protected]

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tank sits at the rear of theproperty with the operationalequipment in an adjacentbuilding. This is a simplesystem to install and a simplesystem to operate, as the wateris used for fire sprinklers andother fire-fighting needs.

Case Studies | 165

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LEFT:Downspout connectedto a drainpipe leadingto cisternRIGHT:Ball tank collectingall downspout drainageprior to cistern

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Roofdetail

View of guttersfrom above

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166 | Design for Water

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View of gutters anddownspout connection

Rainwatercistern

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FIRST GREEN POST OFFICE—8TH AVENUE STATION

The US Postal Service has one ofthe largest construction pro-grams in the nation, owningapprox. 35,000 facilities andbuilding 500 to 700 new facilitieseach year. The Postal Servicerecognizes they need to bestewards in their buildingprocess. In 1993, the PostmasterGeneral issued the USPSEnvironmental Policy andGuiding Principles, which canbe summarized as follows:

• Meet or exceed all applicableenvironmental laws

• Incorporate environmentalconsideration into the busi-ness planning process

• Foster the sustainable use ofnatural resources by promot-ing pollution prevention,reducing waste, recycling, andreusing materials

• Expect every employee to takeownership and responsibility

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for the USPS’s environmentalobjectives

• Work with customers toaddress mutual environmentalconcerns

• Measure our progress on pro-tecting the environment

• Encourage suppliers, vendors,and contractors to comply

with similar environmentalprotection policies

The above list was providedby the 8th Avenue station andis the list of reasons the facilitywas built to be a “Green”Showcase station. It is meantto test materials and systemsfor viability relative to the

Case Studies | 167

Location: Fort Worth, Texas

Type of system: Active rooftop

Year installed: 1998

Annual rainfall: Approx. 30 inches

Catchment area: Rooftop – 25,500 square feet

Containment: Above-grade, two 10,000-galloncisterns

Annual quantitycollected: Approx. 468,000 gallons

Water usage: Landscape irrigation

Equipment involved: Pumps – NoneCistern level controls – NonePressure tank – Three, sizenot availableFilters – None

Contact: United States Postal ServiceFacilities Headquarters,Arlington, VAwww.usps.gov

UJW

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Front of the FirstGreen Post Office

The two 10,000-gallon tanks used forrainwater storage

UJW

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AR,U

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ATESPOSTALSE

RVICE

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standard materials and systemstypically used.

One of the systems beingtested is the rainwater harvestingsystem. Originally, the systemwas meant for toilet flushing,but due to water quality ques-tions the system is currently onlybeing used for landscape estab-lishment. After a period ofmonitoring shows the waterquality provided by the systemmeets City drinking water stan-dards, the system will be used asoriginally intended to flush toi-

lets and put water to other usesthat will allow the station to beoff the water grid, providing itsown water needs. Until the sys-tem provides quality water, thewater will be used to establishthe landscape materials includ-ing its native Texas “buffalograss” lawn. After the land-scaping is well established, nofurther irrigation will berequired (during normal rainfallyears), and the entire “capture”of rainwater estimated to beapproximately 468,000 gallons

168 | Design for Water

Pressure tanksand pump

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Conceptual layout ofrainwater tanks and building

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per year can be devoted to thebuilding and occupants.

The potable water require-ments for the building based ona commercial use of 5 to 6 gal-lons per person per day will beapproximately 55,000 to 60,000gallons per year. The average

domestic water use in Arlingtonis typically higher, at 25 to 40gallons per person per day. Therainwater harvesting systemsaves over $2,800 per year inmunicipally supplied water thatdoes not have to be purchasedby the USPS.

Case Studies | 169

SEATTLE CITY HALL—SUSTAINABLE BUILDING PROGRAM

The Seattle City Hall is part of athree-block area know as theSeattle Civic Center. All build-ings are designed to fit togetherin both form and function. The

sustainable aspect guarantees thebuildings to be constructed fromdurable materials and to be flex-ible to respond to the future.The City Hall was designed tolast for 100 years, with the abilityto adapt to changing servicesand technologies. Several sus-tainable building elements arebrought into the designs includ-ing designing with LEED, socialsustainability, smart mobility,energy and water efficiency, sus-tainable materials, healthy indoorenvironments, and salmon-friendly designs. The rainwatercollection aspect of the buildingfalls under this last category.

The rainwater system at theSeattle City Hall is located in thebasement of the building, wherethe water storage is below thebasement floor in a location thatmakes it very difficult to compre-hend its size simply by viewingthe tank through an access hatch.However, viewing the equipmentin the lower portion of the base-ment allows some comprehensionof the depth of the tank. Therainwater is pumped from the

Location: Seattle, Washington

Type of system: Active rooftop

Year installed: 2003

Annual rainfall: 37 inches

Catchment area: Rooftop – Approx. 25,000square feet

Containment: Below-grade, 224,400-gallonconcrete structure below thebasement floor

Annual quantitycollected: Approx. 518,364 gallons

Water Usage: Toilets and landscape irrigation

Equipment involved: Pumps – Two large municipal-level pumps deliver the rainwaterto the equipment room and abooster pump pushes the waterup to the building for useCistern level controls – ElectronicPressure tank – Pumps pressur-ize linesFilters – No treatment, only adebris filter

Contact: City of Seattle SustainableBuilding Programwww.cityofseattle.net/sustainablebuilding

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LEFT:Sign outside therainwater equip-

ment roomRIGHT:

Mixing tank wheremunicipal fill isadded if needed

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Rainwatertank access

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Equipment for rain-water system; notethat the equipmentis below the top ofthe tank where thephoto was taken

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cistern to a much smaller mixingtank and then to the building’slandscape irrigation and multi-ple toilets—close to 50 of them.The mixing tank is used toswitch to municipal water if thecistern is empty. Using the mix-ing tank allows the cisterns toreserve maximum storage capac-

ity in anticipation of a storm.The rainwater catchment

is expected to decrease thestormwater runoff by 75 per-cent and eliminate the use ofpotable municipal water by 30percent. The yearly budget forflushing the building’s toilets is750,000 gallons.

Case Studies | 171

KING STREET CENTER—KING COUNTY

King Street Center was devel-oped as a partnership betweenKing County, the building ownerCDP King County III, and thebuilding developer WrightRumstad & Company. Thebuilding is located in Seattle’sPioneer Square historic districtand houses both King County’sDepartment of Transportationand Department of NaturalResources. The King StreetCenter has incorporated ornatemetal, concrete, glass, and hard-scape elements into the buildingof a facility that has been placedon the County’s Innovative Artist-Made Building Ports Registry.

The King Street Center wasalso designed to incorporate sus-tainable building design featuresincluding resource saving carpet,recycled glass, energy reducinglights, leftover paints, low VOCfurnishings, recycled ceramicand concrete tiles, and a rain-water catchment system toreduce municipal water usage.The rainwater collection systemwas designed by the building’s

mechanical and plumbing con-tractor to collect rain that fallson the 44,000 square foot rooftopand store it in three 5,400-gallontanks. The rainwater tanks andpumps are located on a lowerlevel “B.” The rainwater passesthrough all three tanks before itgoes through a strainer and finemesh 10-micron bag filters.

The first tank in the linearsystem is a settlement and mix-ing tank. While usage ofrainwater is the system’s first pri-ority, a groundwater supply isprovided to supplement lowwater levels. The groundwater ispumped from below the build-ing’s foundation. A three-waysolenoid valve and float switchesin the third tank monitor andmaintain the water level in thefirst tank. The second tank isalso a mixing tank where thelevel of water is controlled by asolenoid valve and float switchin the third tank. If groundwateris unavailable, then as a lastresort the float switches turn onthe municipal/domestic water

Location: Seattle, Washington

Type of system: Active rooftop

Year installed: 1999

Annual rainfall: 37 inches

Catchment area: Rooftop – 44,000 square feet

Containment: Basement level, three 5,400-gallon concrete tanks for a com-bined storage of 16,200 gallons

Annual quantitycollected: 1.4 million gallons

Water usage: Flushing of approximately118 toilets

Equipment involved: Pumps – Three booster pumpsCistern level controls – ElectronicPressure tank – One tank ismaintained at 115-120 psiFilters – Four 10-Micron fine-mesh bag filters. One strainerand the roof drains to filterdebris. The first tank was alsodesigned as a settling tank.Filters are changed monthly.

Contact: Architect and rainwater consult-ant – MacDonald-MillerCompany, Seattle, Washingtonwww.dnr.metrokc.gov/index.htm

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172 | Design for Water

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LEFT:Building entry

RIGHT:Green roof irrigated

with rainwater

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Controls andpressure tank

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LEFT:FiltersRIGHT:

Three main tanksin basement

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supply that is located in thissecond tank. A minimum waterlevel of 4 feet is required for thesystem to work. From the thirdtank the rainwater goes througha strainer, three booster pumps,and a pressure tank to maintain115 to 120 psi for the building’snon-potable water supply system.

The building was double-plumbed to deliver potablewater to all items needing apotable water supply such assinks, drinking fountains, anddishwashers. The rainwater sup-ply lines provide reclaimed waterto the toilets and urinals. TheKing Street Center “flushing”budget is approximately 2.2 mil-lion gallons annually. The Countyanticipates saving a minimum of1.4 million gallons of domestic

water by using the capturedrainwater. This building and itssustainable features is meant tobe a demonstration facility fordesigners, building owners,developers, and contractors.

The building has won theUS Environmental ProtectionAgency 2001 Energy Star Awardand the estimated cost of therainwater system is approximate-ly $320,000.

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Restroom sign aboutrainwater usage

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Rainwater systemcomponents for theKing Street Center

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The US Department ofAgriculture moved their facilityfrom their Phoenix location, onBaseline Road and 47th Street, tojust outside the Town ofMaricopa, in Maricopa County,Arizona. This southern locationsited in wide open fields allowedexpansion and the potential fora better facility layout. The newfacility allows the dirty fieldwork to transition to the cleaner

labs and offices in a linear fash-ion. This facility contains both apassive rainwater system designedfor a visual, educational purposeand an active system designed tocollect and store rainwater forsite irrigation and conservationof potable water supplies.

The passive educational sys-tem starts with the visible andaesthetically interesting roof ofthe main building, and ends in avery visible way in the facility’scourtyard. The main entry build-ing was designed with a graystanding seam roof that drains tothe center for a depressed ridgeline. The “butterfly” roof drainsto the rear of the main buildingwhere it drops to a custom made3,200-gallon above-ground,round, stainless steel tank. Thetank contains a floor drain andan overflow drain if the tank fillstoo quickly. The overflow allowsthe extra water to enter the

174 | Design for Water

US DEPARTMENT OF AGRICULTURE—RESEARCH FACILITY

Location: Maricopa County, Arizona

Type of system: Active and passive rooftop andground level hard-surface collection

Year installed: 2005

Annual rainfall: 7 inches

Catchment area: Rooftop – 100,000 square feet

Containment: One above-grade 3,200-galloncustom stainless steel tank andone 40,000-gallon below-gradecorrugated steel metal pipe for acombined storage of 43,200gallons

Annual quantitycollected: 200,000 gallons

Water usage: Site irrigation

Equipment involved: Pumps – Yes; size not availableCistern level controls – Yes;type not availablePressure tank – One; size notavailableFilters – Not available

Contact: Architect – Dibble & Associates,PhoenixRainwater consultant – SmithGroup, Phoenixwww.ars.usda.gov/is/pr/2006/060424.htmwww.corestructaz.com

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View of stainless steeltank from the ground

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Butterfly roof gutterand splash panel tostainless steel tank

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LEFT:Passive rainwater har-vesting: Channel withdrains to the landscapeRIGHT:Pressure tank andequipment box

Overflow frombelow-grade tank tobasin for infiltration

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active collection system.The passive system continues

as the rainwater drains to an at-grade bubbler box and trough.The trough runs the length of thecourtyard to deliver the rainwaterto five smaller perpendiculartroughs that direct the water tocourtyard trees. The courtyardcontains an overflow drain and thelower end of the trough containsand overflow drain. Both over-flow drains empty to the activecollection system storage tank.

The active system collectsrainwater runoff from all build-ings through a system of roofdrains and below-grade stormdrain pipes. The pumping equip-ment and rainwater systemcontrols are contained in a steelcabinet adjacent to a facilityparking lot. The corrugatedmetal pipe (CMP) that is used asa cistern can hold 40,000 gallons.The collected rainwater is usedfor the 5,000-gallon-per-daylandscape drip-irrigation demand.

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Conceptual diagram ofthe rainwater system atthe US Department of

Agriculture facility

ROANOKE REGIONAL JAIL—WESTERN VIRGINIA REGIONAL JAIL AUTHORITY

The Roanoke Regional Jail, whencompleted, will have 605 bedsfor individuals who have beentried and sentenced, are beingheld awaiting trial, or have somespecial problem such as needingto be separated from others. It isa short-time stay facility and willhelp to solve some overcrowding

in other jails. The jail, expectedto stand for 50 to 100 years, willbe an environmentally sensitivebuilding with energy-savingand eco-friendly components.USGBC LEED Certified level isbeing sought for the facility.

Rainwater will be collectedfrom the roof of the jail and

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used for washing and toiletflushing. The rainwater willmostly be used for the laundry

services because rainwater issoft water and will reduce theamount of soap the facility willneed to purchase. The facilitywill have less stormwater runoffbecause the inmates will nothave in-person visitors. Theywill communicate with visitorsvia videoconferencing fromthe localities where they wereconvicted. This means lessparking areas are needed, andthe parking that is requiredwill not have curbs, to allow anatural runoff into the land-scaped areas for infiltration.Some other sustainable featuresdesigned into the facility plansare as follows:

• Vacuum flush toilet unitsusing 0.6 gallons per flush

• Green roofs

• Stormwater catchment andreuse for roof cooling

• Recycling stormwater for usein evaporative cooling tower

Case Studies | 177

Location: Roanoke County, Virginia

Type of system: Active rooftop

Year installed: 2006

Annual rainfall: 42 inches

Catchment area: Rooftop – 290,000 square feetBelow-grade, four 30,000-gallonfiberglass tanks

Annual quantitycollected: Approx. 6.8 million gallons

Water Usage: Kitchen cart washers, laundry,toilets, and landscape irrigation

Equipment anticipated: Pumps – Jet pump, automaticswitch to municipal water ifcistern is dryCistern level controls – Floatswitches and level sensorPressure tank – YesFilters – Floating cistern filter inone tank, bag filter, in-line sedi-ment filter, in-line carbon filter,and a UV light

Contact: Rainwater ManagementSolutions, Salem, Virginiawww.rainwatermanagement.com

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• Reuse of cooling tower blow-down water

• Rainwater catchment forlaundry use

• Siphonic roof drainage system

The siphonic roof drainageis a technique for sizing drainagepiping to allow the drainage sys-

tem to flow full bore, to utilizethe full cross-sectional area of thepiping, and to exploit the poten-tial energy available from theroof elevation to the point ofdischarge. It represents an under-standing of fluid dynamics. Thissystem drains the roof runoff toa storage tank more quickly.

178 | Design for Water

NORTH CAROLINA LEGISLATIVE BUILDING—RAINWATER CATCHMENT SYSTEM

The North Carolina LegislativeBuilding rainwater and air con-

ditioning condensate collectionand reuse system is working as

INNOVATIVEDESIGN

Excavation for the rain-water tanks next to theLegislative Building

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Typical jailtoilet

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planned. The system, planned asan educational tool, will help tomitigate the impacts of droughtwhile helping the environmentand reducing energy use associ-ated with water treatment anddistribution. The system catches2,292,000 gallons of rain and669,000 gallons of used waterfrom the building’s air condi-tioning system for a total water

catchment of 2,961,000 gallonsannually. Three cisterns arelocated below-grade in thesouthwest corner of theLegislative Building’s lawn tohold the captured water while agauge is located in the buildingto allow visitors to view the vol-ume stored in the cisterns.

The rainwater flows off theroof and the condensate flows

Case Studies | 179

Location: Raleigh, North Carolina

Type of system: Active rooftop

Year installed: 2006

Annual rainfall: Approx. 45.2 inches

Catchment area: Rooftop – Approx. 90,000square feet

Containment: Below-grade three 18,000-gallonconcrete tanks for 54,000gallons total

Annual quantitycollected: 2.3 million gallons

Water usage: Landscape irrigation and fountainreplenishment

Equipment involved: Pumps – Ebara submersible,150 gallons per minuteCistern level controls – RSIsimplex pump controlPressure tank – NoneFilters – Kristal Klear L8830-3FAC-15

Contact: Innovative Design, Inc., Raleigh,North Carolinawww.innovativedesign.netwww.ncleg.net/cistern/web/index.html

INNOVATIVEDESIGN

TOP:Installed tankswith manholesBOTTOM:Tanks beingassembled inexcavated hole

INNOVATIVEDESIGN

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180 | Design for Water

INNOVATIVEDESIGN

Exposed manholesand covered tanks

INNOVATIVEDESIGN

Covered tanks

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Conceptual processfor the rainwater

system at the NorthCarolina Legislative

Building

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from the air conditioning unitsas they come together througha series of roof drains into one18-inch pipe. The pipe connectsto a sediment filter and thenreleases the water into thetanks. Overflow water is allowedto exit into the municipal stormsystem. Once in the tanks, therainwater is filtered, pressurized,and pumped to the irrigationsupply line. The captured rain-water and condensate water is

used for the following tasks:

• Irrigation of grounds andgardens of the LegislativeBuilding

• Irrigation of isolated gardensthroughout state governmentcomplex

• Provides water for fountainsaround the LegislativeBuilding

• Reduces nitrogen pollution intoRaleigh’s stormwater system

Case Studies | 181

Alternate Source Water Collection Systems

AIR CONDITIONING CONDENSATE—AND COOLING TOWER BLOWDOWNCOLLECTION: AN ALTERNATE WATER SUPPLY

Air conditioning has become anassumed benefit of living in anurban environment; we assumethe building we work in, havelunch in, exercise in, and watchmovies in will be air condi-tioned. Hardly anyone thinksabout it, except for the peopleresponsible for the maintenanceof the system. Large-scale airconditioning systems are typical-ly either a cooling tower or achiller. These units use millionsof gallons of water a year touphold our expectations thatour environments will be cool.The water released from theseprocesses is usually warmer thanthe environment water and canaffect the aquatic life by chang-ing stream temperatures. Largequantities of salt and dust canalso be released into sewer sys-tems.43 It is also a large quantity

of water that the city wastewatertreatment system must accept.One way to eliminate any envi-ronmental damage and reducemunicipal concerns over theextra water is to capture andreuse the water as an alternatewater supply.

Rainwater tanks at anAustin, Texas homelessshelter collects rain-water and air condi-tioning condensate

BILLHOFFMAN,A

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Eddie Wilcut, ConservationManager with the San AntonioWater System, Texas has puttogether a guidebook on how tocalculate the condensate a sys-tem is capable of producing. Hebelieves the rising water andsewer rates have spurred busi-nesses across the country toexplore ways to reduce theirwater use. Mr. Wilcut alsobelieves that reusing condensateproduced by air conditioningequipment can be a cost-effec-tive method for companies to

achieve their water conservationgoals. He has provided the fol-lowing information from hisguidebook for determining theamount of condensate that canbe collected from an air-condi-tioning unit.

From The Air ConditioningCondensate Guidebook byEddie Wilcut:

The normal, daily operationof air conditioning equip-ment can produce largeamounts of high-quality

182 | Design for Water

BILLHOFFMAN,A

USTINUTILITY

Orical’s Air-conditioningCondensate RecoverySystem for cooling

tower makeup water

BILLHOFFMAN,A

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Orical’s piping tocooling tower

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water that is ideal for reusein cooling towers, for land-scape irrigation, or for reusein industrial processes. Yet,more often than not, thispotential resource is regard-ed as wastewater. Mostindustrial users direct theircondensate to the sanitarysewer system or storm drain,where the opportunity tosave water and money islost. The Air-conditioningCondensate Guidebook is aresource for those who areinterested in exploring thepossibility of condensatereuse for current operationsor planned facilities.

The Guidebook contains:

• Information relating toheating, ventilation and airconditioning (HVAC) systemsand processes that result incondensate production

• Basic atmospheric andpsychrometric data andterminology

• Methods and calculationsfor estimating condensateproduction associated withHVAC Systems

• Case studies from local busi-nesses that are practicingcondensate recovery

• Details on SAWS ConservationPrograms that can help large-scale users cover a portion ofthe cost of condensate recov-ery projects

Simply put, condensation isthe process by which water vaporturns from a gas state into a liq-uid state. Consider what happenswhen you set a glass of ice wateroutside on a warm, sunny day.The temperature of the outsideair is higher than the temperatureof the surface of the glass. As thewater vapor in the air surround-ing the glass cools down itchanges from a gaseous state toa liquid and the glass appears tosweat. This “sweat” is actuallycondensate forming on the sur-face of the glass. The same effectcan be seen in the winter whencondensate forms on the insideof windows. As air cools, its abil-ity to hold water in the form ofvapor decreases. The same prin-ciples that cause condensate toform on a glass of ice water orwindowpane, and dew to formon the grass, are responsible forthe generation of condensate byair conditioning equipment.

To understand the condensateprocess one must understand thenature of water vapor and psy-chrometry. Water vapor is everpresent in the air that surroundsus. Psychrometry is the study ofmoisture in the air and of thechanges in the moisture holdingcapacity of the air in relation totemperature change. Simply stat-ed, as air temperature increases,its capacity for holding moistureincreases. As air temperaturedecreases, the capacity to holdmoisture also decreases. Relative

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humidity measures the amountof water that the air holds inrelation to the maximumamount of water (AbsoluteHumidity) it could hold.

At a temperature of 90degrees Fahrenheit and a relativehumidity of 80 percent, air willhold approximately 12.8 grainsof moisture per cubic foot of air,but it is capable of holding 20percent more moisture or 15grains per cubic foot of air. Asthe air temperature decreases,the percentage of the humidityin the air increases in relationto the decreasing moistureholding capacity. At 84 degreesFahrenheit, the same air canonly hold 12.8 grains of mois-ture and becomes saturated at100 percent relative humidity.At 100 percent relative humidity,the air reaches its dewpoint. It isat this point that condensatebegins to form.

While the results of reachingthe dewpoint are apparenteveryday in our surroundings,nowhere is it more dramaticthan in large air conditioningsystems where the rapid coolingof air can result in the produc-tion of several thousand gallonsof condensate water per day.

Air conditioning systemsvary in size and configuration.But whether it is a small windowunit, a 5-ton system used for asingle-family residence, or a1,000-ton system used at a man-ufacturing facility, the process of

conditioning air is basically thesame. Single-family residencesand many businesses can beeffectively cooled by a unitarysystem where refrigerant gas iscompressed and run throughcoils to cool the air that passesover the air-conditioning coils.Very large or multi-story facili-ties may require a different typeof system that uses an evapora-tive cooling tower and chilledwater instead of a refrigerantgas. In these systems, cooledwater leaves the cooling towerand is run through a chiller. Achiller is a heat exchanger thatuses refrigerant to cool andwater to transfer heat as partof the air conditioning process.A chiller is comprised of anevaporator, condenser, and acompressor system. The heatload is transferred to the coolingwater and then sent back to thecooling tower to be dissipated.

Both general types of sys-tems incorporate some type ofair handler. Air handlers general-ly incorporate an evaporatoralong with a ventilation fan. Asthe fan pushes warm, moisture-laden air over the evaporator, theair temperature drops, causingwater vapor to condense out andaccumulate on the coils. Thecool air is sent into our homesand businesses, while the con-densate is collected in a drip panwhere it is usually drained to theoutside of the structure or intothe sanitary sewer and simply

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forgotten. The average residen-tial air conditioning system canproduce five gallons of conden-sate in one hour during timeswith high relative humidity.When you consider that largecommercial and industrial facili-ties often have air-conditioningsystems with several hundredtimes more capacity than theaverage residential system, youcan start to see the potential forindustrial air conditioning sys-tems to produce large amountsof condensate.

Several factors will deter-mine how much condensatecan be produced by a facility.However, the predominantfactors are weather, industrialprocesses/human factors, andcooling capacity.

WEATHERAs an example, San Antonioexperiences an abundance ofwarm, sunny weather. In thewinter, 50 percent of the days aresunny and in the summer thatfigure increases to 70 percent. Infact, this area averages over 300sunny days annually. Maximumdaily temperatures during thesummer are above 90 degreesover 80 percent of the time.In addition, San Antonio entersa sub-tropical weather patternin the summer. The relativehumidity is highest in the earlymorning and decreases as tem-peratures warm up duringthe day. The average relative

humidity in San Antonio rangesaround 50 percent in the lateafternoon. That’s not as muchas Houston to the east—Houston’s average relativehumidity ranges around 63percent in the afternoon. Thisis a substantial amount of mois-ture in the air and it makes ahot day feel even hotter. Theresult of all of these climaticfactors combined is that air con-ditioning equipment mustoperate constantly throughoutthe day in order to meet therequirements of most industri-al/commercial facilities.

INDUSTRIAL PROCESSESAND HUMAN FACTORS

Condensate production will alsobe greatly influenced by themanufacturing processes andhuman activities that occurwithin a facility. This is com-monly referred to as the LatentCooling Load. The latent coolingload is the load created by mois-ture in the air, including fromoutside air infiltration and thatfrom indoor sources such asoccupants, plants, cooking,showering, etc.

Computers, copy machines,and other office necessities aswell as lighting and manufactur-ing equipment all introduce heatinto the working environment.Manufacturing processes such assterilization or food preparationthat generate large amounts ofsteam and heat will increase the

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potential for condensate produc-tion by introducing addedmoisture in the air. Also, certainworking environments like cleanrooms require a closely con-trolled humidity. Thesesituations require A/C equip-ment to work harder and runlonger to maintain specificworking environments andtherefore can lead to increasedcondensate production.

Large-scale facilities that arenot used for manufacturing canstill produce a useable amountof condensate. Human activityalone can dramatically influencethe potential for condensaterecovery. Facilities that experi-ence a high amount of foottraffic have large amounts ofoutside air continually broughtinside, causing increases in theindoor temperature and humidi-ty. Human respiration and bodyheat can also increase indoortemperature and humidity.While seemingly insignificant onan individual basis, the heat andmoisture generated by a largenumber of people can signifi-cantly affect indoor aircharacteristics.

Calculating CondensateProduction RatesEstimating condensate productionis, at best, a time-consumingprocess. While several sets of sci-entific and mathematicequations do exist that, whencombined, allow one to approxi-

mate the amount of condensatethat can be produced at a giventime under a given set of para-meters, a step-by-step processneeds to be assembled.Following is a first attempt atestablishing a methodology forcalculating the potential for con-densate production.

Step 1—Determine the Capacityof your system in TonnageThe capacity of an air condition-er is measured by the amount ofcooling it can achieve when run-ning continuously. The totalcapacity is the sum of a unit’sability to remove moisture fromthe air, otherwise referred to aslatent capacity; and the unit’sability to reduce temperature,otherwise known as sensiblecapacity. Each of these capacitiesis rated in British Thermal Units(Btu) per hour (Btu/h). It takes12,000 Btu/h to melt one ton ofice in a 24-hour period. A unit’scapacity is dependant upon suchfactors as the outside and insideconditions. As it gets hotter out-side (or cooler inside) the capacityto further cool the air decreasesas the load on the systemincreases. The capacity at a stan-dard set of conditions is oftenreferred to as “tons” of cooling.

A ton of air conditioningrelates a system’s cooling capaci-ty to the cooling effect associatedwith melting one ton of ice dur-ing a 24-hour period. Therefore,a system rated at 5 tons can pro-

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duce the same amount of coldair as melting five tons of iceduring a 24-hour period hour,which consequently wouldrequire 60,000 Btu per hour.

Typical residential central airconditioning systems can rangebetween two and five tons ofcooling capacity, while largecommercial buildings can havesystems that range from severalhundred to several thousandtons of cooling capacity.

CAPACITY = _______ TONS

Step 2—Determine the Percentageof Total Capacity at which yoursystem is runningPercentage of Total Capacity isthe actual percentage of themaximum rated capacity of thesystem necessary to accomplish adesired temperature. Multiplyingthe Percentage of Total Capacityby the Maximum Rated Capacitywill result in an indication of theactual amount of cooling a sys-tem is doing. In effect, a1,000-ton system operated at aPercentage of Total Capacityequal to 70 percent is equivalentto a 700-ton system operating at100 percent.

PERCENTAGE OF TOTALCAPACITY = _______ PERCENT

Step 3—Determine SpecificHumidity for air entering the airhandlerSpecific Humidity (Table 5.1) is

a measurement of the grains ofmoisture per mass of air at agiven temperature and baromet-ric pressure. (Look up SpecificHumidity at a given Temperatureand Relative Humidity). SpecificHumidity is expressed as grainsof moisture per cubic foot of air.

It is important to note that airhandlers will often handle a mix-ture of outside and inside air. Inthose cases, it is necessary to iden-tify what percentage of the make-up air is external and what per-centage is internal. Inside air is notthe same as air directly leavingthe air handler. The temperatureof inside air will be affected byprocesses and human factorsunique to a specific building.

Once you have determinedthese percentages, you will needto calculate the Adjusted Temper-ature. Adjusted Temperature =(Percent of Indoor Make-up AirX Temperature in Degrees F) +(Percent of Outdoor Make-upAir X Temperature in DegreesF).You can look up OutdoorRelative Humidity using real timedata on the Internet. You canalso determine outdoor relativehumidity using a psychrometer.

Once you have determinedthese percentages, you will needto calculate the adjusted relativehumidity. Adjusted RelativeHumidity = (Percent of IndoorMake-up Air X Percent RelativeHumidity) + (Percent ofOutdoor Make-up Air X PercentRelative Humidity).

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Step 4—Calculate SpecificHumidity for air leaving theAir HandlerLook up Specific Humidity(Table 5.1) at a givenTemperature and RelativeHumidity. Specific Humidityis expressed as grains of mois-ture per cubic foot of air. Youcan determine indoor relativehumidity using a psychrometer.Typically, indoor relative humid-ity is recommended at or below50 percent.

Step 5 – Calculate the differencein Specific Humidity between theIncoming and Outgoing airUsing data from Step 3 and Step4 calculate Specific Humidityas follows:

Specific Humidity of IncomingAir – Specific Humidity ofOutgoing Air = Grains ofMoisture per ft3 of air removedas a result of the cooling process.

Is the difference a positivenumber?

NO – Condensate is not beingproduced and you do not needto continue with the calculation.

YES – Condensate is being pro-duced. Proceed to Step 6

Step 6—Calculate MaximumAir FlowUsing data from Step 1calculateMaximum Air Flow as follows:

One Ton of Cooling = 350 ft3

Per Minute/Ton

System Capacity x 350 ft3 PerMinute/Ton = Air Flow in ft3

Per Minute

____ Tons X 350 ft3 PerMinute/Ton = Max Air Flow inft3 Per Minute

Step 7—Calculate actual air flowCombine data from Step 6 andStep 2 to calculate Actual AirFlow as follows:

Max Air Flow X Percentage ofTotal Capacity = Actual Air Flow

______ ft3 Per Minute X_____percent = Actual Air Flowin ft3 Per Minute

Step 8—Calculate totalcondensate produced asGrains of Moisture producedCombine data from Step 5 andStep 7 to calculate TotalCondensate as follows:

Actual Air Flow in ____ft3 PerMinute X ____Grains ofMoisture per ft3 = ____Grainsof Moisture Per Minute

Step 9—Convert total Grains ofMoisture produced to Gallons perMinute (GPM)Use data from Step 8 to calculatethe following:

Note: 1 lb of water = 7,000Grains of Moisture

1 gallon of water weighs 8.33pounds

(____ Grains of Moisture/Minute) + (7,000 Grains/lb x8.33 lb/gal) = the following:

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(____ Grains/Minute) X (58,310Grains /Gallon) = the following:

(____ Grains/Minute) X (1Gallon/58,310 Grains) = thefollowing:

_______ Gallons/Minute

The following is an actualcalculation of a system’s air-con-ditioning condensate productionbased on the given data and theabove formulas:

System area conditions:

Make-up air source – 100 per-cent outside air

Outdoor temperature – 90degrees Fahrenheit

Outdoor relative humidity – 80percent

Air temperature leaving the airhandler – 75 degreesFahrenheit

Relative humidity leaving the airhandler – 50 percent

Standard atmospheric pressure(Sea Level) = 29.92 in Hg(inches of mercury)

AC system tonnage – 100 TonsPercentage of total capacity = 80

percent350 cubic feet per minute

(CFM) per ton of cooling

Step 1—Determine the Capacityof your system in Tonnage100 Tons

Step 2—Determine the Percentageof Total Capacity at which yoursystem is running80 percent

Step 3—Using Table 5.1, look upSpecific Humidity for air enteringthe Air Handler90 Degrees F at 80 percent RH =12.02 Grains/ft3 (Table 5.1)

Step 4—Calculate Specific Humidityfor air leaving the Air Handler75 Degrees at 50 percent RH =4.8 Grains/ft3 (Table 5.1)

Step 5—Calculate the differencein Specific Humidity between theIncoming and Outgoing airSH (Incoming) – SH (Outgoing)= Difference in Specific Humidity

12.02 – 4.8 = 7.22

Difference is a positive number -Continue

Step 6—Calculate MaximumAir Flow100 Tons X 350 ft3 PerMinute/Ton = 35,000 ft3 PerMinute

Step 7—Calculate Actual Air FlowMax Air Flow X Percentage ofTotal Capacity = Actual Air Flow

35,000 ft3 Per Minute X 80 per-cent = 28,000 ft3 Per Minute

Step 8—Calculate TotalCondensate produced as Grainsof Moisture producedActual Air Flow Per Minute XGrains of Moisture per ft3 =Grains of Moisture Per Minute

28,000 ft3 Per Minute X 7.22Grains of Moisture per ft3 =202,160 Grains of Moisture PerMinute

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190 | Design for Water

Relative

Humidity

510

1520

2530

3540

4550

5560

6570

7580

8590

9510

0

400.

135

0.26

90.

404

0.53

80.

673

0.80

70.

942

1.07

61.

211

1.34

61.

480

1.61

51.

749

1.88

42.

018

2.15

32.

287

2.42

22.

556

2.69

141

0.13

90.

278

0.41

60.

555

0.69

40.

833

0.97

21.

110

1.24

91.

388

1.52

71.

666

1.80

41.

943

2.08

22.

221

2.36

02.

498

2.63

72.

776

420.

143

0.28

70.

430

0.57

40.

717

0.86

01.

004

1.14

71.

290

1.43

41.

577

1.72

11.

864

2.00

72.

151

2.29

42.

437

2.58

12.

724

2.86

843

0.14

80.

297

0.44

50.

593

0.74

10.

890

1.03

81.

186

1.33

51.

483

1.63

11.

779

1.92

82.

076

2.22

42.

373

2.52

12.

669

2.81

82.

966

440.

154

0.30

70.

461

0.61

40.

768

0.92

11.

075

1.22

81.

382

1.53

51.

689

1.84

21.

996

2.14

92.

303

2.45

62.

610

2.76

42.

917

3.07

145

0.15

90.

318

0.47

70.

636

0.79

60.

955

1.11

41.

273

1.43

21.

591

1.75

01.

909

2.06

82.

227

2.38

72.

546

2.70

52.

864

3.02

33.

182

460.

165

0.33

00.

495

0.66

00.

825

0.99

01.

155

1.32

01.

485

1.65

01.

815

1.98

02.

145

2.31

02.

475

2.64

02.

805

2.97

03.

135

3.30

047

0.17

10.

342

0.51

40.

685

0.85

61.

027

1.19

91.

370

1.54

11.

712

1.88

42.

055

2.22

62.

397

2.56

82.

740

2.91

13.

082

3.25

33.

425

480.

178

0.35

60.

533

0.71

10.

889

1.06

71.

245

1.42

21.

600

1.77

81.

956

2.13

32.

311

2.48

92.

667

2.84

53.

022

3.20

03.

378

3.55

649

0.18

50.

369

0.55

40.

739

0.92

31.

108

1.29

31.

477

1.66

21.

847

2.03

12.

216

2.40

12.

586

2.77

02.

955

3.14

03.

324

3.50

93.

694

500.

192

0.38

40.

576

0.76

80.

960

1.15

11.

343

1.53

51.

727

1.91

92.

111

2.30

32.

495

2.68

72.

879

3.07

03.

262

3.45

43.

646

3.83

851

0.19

90.

399

0.59

80.

798

0.99

71.

197

1.39

61.

596

1.79

51.

995

2.19

42.

393

2.59

32.

792

2.99

23.

191

3.39

13.

590

3.79

03.

989

520.

207

0.41

50.

622

0.82

91.

037

1.24

41.

451

1.65

91.

866

2.07

32.

281

2.48

82.

695

2.90

33.

110

3.31

73.

525

3.73

23.

939

4.14

753

0.21

60.

431

0.64

70.

862

1.07

81.

293

1.50

91.

724

1.94

02.

155

2.37

12.

586

2.80

23.

018

3.23

33.

449

3.66

43.

880

4.09

54.

311

540.

224

0.44

80.

672

0.89

61.

120

1.34

41.

569

1.79

32.

017

2.24

12.

465

2.68

92.

913

3.13

73.

361

3.58

53.

809

4.03

34.

258

4.48

255

0.23

30.

466

0.69

90.

932

1.16

51.

398

1.63

11.

864

2.09

72.

330

2.56

22.

795

3.02

83.

261

3.49

43.

727

3.96

04.

193

4.42

64.

659

560.

242

0.48

40.

726

0.96

91.

211

1.45

31.

695

1.93

72.

179

2.42

22.

664

2.90

63.

148

3.39

03.

632

3.87

44.

117

4.35

94.

601

4.84

357

0.25

20.

503

0.75

51.

007

1.25

81.

510

1.76

22.

013

2.26

52.

517

2.76

83.

020

3.27

23.

524

3.77

54.

027

4.27

94.

530

4.78

25.

034

580.

262

0.52

30.

785

1.04

61.

308

1.56

91.

831

2.09

22.

354

2.61

52.

877

3.13

83.

400

3.66

23.

923

4.18

54.

446

4.70

84.

969

5.23

159

0.27

20.

543

0.81

51.

087

1.35

91.

630

1.90

22.

174

2.44

62.

717

2.98

93.

261

3.53

23.

804

4.07

64.

348

4.61

94.

891

5.16

35.

435

600.

282

0.56

50.

847

1.12

91.

411

1.69

41.

976

2.25

82.

540

2.82

33.

105

3.38

73.

669

3.95

24.

234

4.51

64.

798

5.08

15.

363

5.64

5

610.

293

0.58

60.

879

1.17

21.

466

1.75

92.

052

2.34

52.

638

2.93

13.

224

3.51

73.

810

4.10

34.

397

4.69

04.

983

5.27

65.

569

5.86

2

620.

304

0.60

90.

913

1.21

71.

521

1.82

62.

130

2.43

42.

739

3.04

33.

347

3.65

13.

956

4.26

04.

564

4.86

85.

173

5.47

75.

781

6.08

6

630.

316

0.63

20.

947

1.26

31.

579

1.89

52.

211

2.52

62.

842

3.15

83.

474

3.78

94.

105

4.42

14.

737

5.05

35.

368

5.68

46.

000

6.31

6

640.

328

0.65

50.

983

1.31

11.

638

1.96

62.

293

2.62

12.

949

3.27

63.

604

3.93

24.

259

4.58

74.

914

5.24

25.

570

5.89

76.

225

6.55

3

650.

340

0.68

01.

019

1.35

91.

699

2.03

92.

379

2.71

83.

058

3.39

83.

738

4.07

84.

417

4.75

75.

097

5.43

75.

777

6.11

66.

456

6.79

6

660.

352

0.70

51.

057

1.40

91.

762

2.11

42.

466

2.81

83.

171

3.52

33.

875

4.22

84.

580

4.93

25.

285

5.63

75.

989

6.34

16.

694

7.04

6

670.

365

0.73

01.

095

1.46

11.

826

2.19

12.

556

2.92

13.

286

3.65

14.

016

4.38

24.

747

5.11

25.

477

5.84

26.

207

6.57

26.

937

7.30

3

680.

378

0.75

71.

135

1.51

31.

891

2.27

02.

648

3.02

63.

405

3.78

34.

161

4.53

94.

918

5.29

65.

674

6.05

36.

431

6.80

97.

188

7.56

6

690.

392

0.78

41.

175

1.56

71.

959

2.35

12.

742

3.13

43.

526

3.91

84.

310

4.70

15.

093

5.48

55.

877

6.26

86.

660

7.05

27.

444

7.83

6

700.

406

0.81

11.

217

1.62

22.

028

2.43

42.

839

3.24

53.

650

4.05

64.

462

4.86

75.

273

5.67

86.

084

6.49

06.

895

7.30

17.

706

8.11

2

GRAINS

OFMOISTUR

EPERCUBICFOOT

OFAIR

Temperature – Degrees F

Page 210: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

Case Studies | 191

Temperature – Degrees F

510

1520

2530

3540

4550

5560

6570

7580

8590

9510

0

710.

420

0.84

01.

259

1.67

92.

099

2.51

92.

938

3.35

83.

778

4.19

84.

617

5.03

75.

457

5.87

76.

296

6.71

67.

136

7.55

67.

975

8.39

5

720.

434

0.86

81.

303

1.73

72.

171

2.60

53.

040

3.47

43.

908

4.34

24.

777

5.21

15.

645

6.07

96.

513

6.94

87.

382

7.81

68.

250

8.68

5

730.

449

0.89

81.

347

1.79

62.

245

2.69

43.

143

3.59

24.

041

4.49

04.

939

5.38

85.

838

6.28

76.

736

7.18

57.

634

8.08

38.

532

8.98

1

740.

464

0.92

81.

393

1.85

72.

321

2.78

53.

249

3.71

34.

178

4.64

25.

106

5.57

06.

034

6.49

96.

963

7.42

77.

891

8.35

58.

819

9.28

4

750.

480

0.95

91.

439

1.91

92.

398

2.87

83.

358

3.83

74.

317

4.79

75.

276

5.75

66.

235

6.71

57.

195

7.67

48.

154

8.63

49.

113

9.59

3

760.

495

0.99

11.

486

1.98

22.

477

2.97

33.

468

3.96

44.

459

4.95

55.

450

5.94

56.

441

6.93

67.

432

7.92

78.

423

8.91

89.

414

9.90

9

770.

512

1.02

31.

535

2.04

62.

558

3.06

93.

581

4.09

34.

604

5.11

65.

627

6.13

96.

651

7.16

27.

674

8.18

58.

697

9.20

89.

720

10.2

32

i78

0.52

81.

056

1.58

42.

112

2.64

03.

168

3.69

64.

224

4.75

25.

280

5.80

86.

336

6.86

57.

393

7.92

18.

449

8.97

79.

505

10.0

3310

.561

790.

545

1.09

01.

634

2.17

92.

724

3.26

93.

814

4.35

94.

903

5.44

85.

993

6.53

87.

083

7.62

88.

172

8.71

79.

262

9.80

710

.352

10.8

97

800.

562

1.12

41.

686

2.24

82.

810

3.37

23.

934

4.49

65.

058

5.62

06.

181

6.74

37.

305

7.86

78.

429

8.99

19.

553

10.1

1510

.677

11.2

39

810.

579

1.15

91.

738

2.31

82.

897

3.47

64.

056

4.63

55.

215

5.79

46.

373

6.95

37.

532

8.11

28.

691

9.27

09.

850

10.4

2911

.009

11.5

88

820.

597

1.19

41.

792

2.38

92.

986

3.58

34.

180

4.77

75.

375

5.97

26.

569

7.16

67.

763

8.36

18.

958

9.55

510

.152

10.7

4911

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11.9

44

830.

615

1.23

11.

846

2.46

13.

076

3.69

24.

307

4.92

25.

538

6.15

36.

768

7.38

37.

999

8.61

49.

229

9.84

510

.460

11.0

7511

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12.3

06

840.

634

1.26

71.

901

2.53

53.

169

3.80

24.

436

5.07

05.

704

6.33

76.

971

7.60

58.

238

8.87

29.

506

10.1

4010

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11.4

0712

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12.6

75

850.

653

1.30

51.

958

2.61

03.

263

3.91

54.

568

5.22

05.

873

6.52

57.

178

7.83

08.

483

9.13

59.

788

10.4

4011

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11.7

4512

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13.0

50

860.

672

1.34

32.

015

2.68

63.

358

4.03

04.

701

5.37

36.

044

6.71

67.

388

8.05

98.

731

9.40

210

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10.7

4611

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12.0

8912

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13.4

32

870.

691

1.38

22.

073

2.76

43.

455

4.14

64.

837

5.52

86.

219

6.91

07.

601

8.29

28.

983

9.67

410

.365

11.0

5611

.748

12.4

3913

.130

13.8

21

880.

711

1.42

22.

132

2.84

33.

554

4.26

54.

976

5.68

66.

397

7.10

87.

819

8.52

99.

240

9.95

110

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11.3

7312

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12.7

9413

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14.2

16

890.

731

1.46

22.

193

2.92

43.

654

4.38

55.

116

5.84

76.

578

7.30

98.

040

8.77

19.

501

10.2

3210

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11.6

9412

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13.1

5613

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14.6

18

900.

751

1.50

32.

254

3.00

53.

757

4.50

85.

259

6.01

06.

762

7.51

38.

264

9.01

69.

767

10.5

1811

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12.0

2112

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13.5

2314

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15.0

26

910.

772

1.54

42.

316

3.08

83.

860

4.63

25.

404

6.17

66.

948

7.72

18.

493

9.26

510

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10.8

0911

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12.3

5313

.125

13.8

9714

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15.4

41

920.

793

1.58

62.

379

3.17

33.

966

4.75

95.

552

6.34

57.

138

7.93

18.

724

9.51

810

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11.1

0411

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12.6

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14.2

7615

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15.8

63

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815

1.62

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444

3.25

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073

4.88

75.

702

6.51

67.

331

8.14

58.

960

9.77

410

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11.4

0412

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13.0

3313

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14.6

6215

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16.2

91

940.

836

1.67

32.

509

3.34

54.

181

5.01

85.

854

6.69

07.

527

8.36

39.

199

10.0

3510

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11.7

0812

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13.3

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15.0

5315

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16.7

26

950.

858

1.71

72.

575

3.43

34.

292

5.15

06.

008

6.86

77.

725

8.58

49.

442

10.3

0011

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12.0

1712

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13.7

3414

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15.4

5016

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17.1

67

960.

881

1.76

22.

642

3.52

34.

404

5.28

56.

165

7.04

67.

927

8.80

89.

688

10.5

6911

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12.3

3113

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14.0

9214

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15.8

5416

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17.6

15

970.

903

1.80

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710

3.61

44.

517

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16.

324

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88.

131

9.03

59.

938

10.8

4211

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12.6

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14.4

5615

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16.2

6317

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18.0

70

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927

1.85

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64.

633

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96.

486

7.41

28.

339

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510

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11.1

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12.9

7213

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14.8

2515

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16.6

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18.5

31

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950

1.90

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3.80

04.

750

5.70

06.

650

7.59

98.

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9.49

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11.3

9912

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13.2

9914

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15.1

9916

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17.0

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18.9

99

100

0.97

41.

947

2.92

13.

895

4.86

85.

842

6.81

67.

789

8.76

39.

737

10.7

1011

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12.6

5713

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14.6

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16.5

5217

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18.4

9919

.473

Page 211: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

Step 9—Convert Total Grains ofMoisture produced to Gallons perMinute (GPM)202,160 Grains/Minute X (1Gallon/58,310 Grains) = 3.46Gallons Per Minute (GPM)

Condensate is generally ahigh quality source of water,making it ideal for numerousapplications. Because of theremoval of minerals during theevaporation process, condensateis similar in water quality to dis-tilled water. In condensate,suspended solids, turbidity, andsalinity are low and the pH isneutral to slightly acidic.

It is important to keep air-conditioning equipment as cleanas possible in order to ensure thatcondensate stays uncontaminated.In particular, the evaporatorcoils and drip trays should bekept free of dust, dirt and otherdebris. As condensate is formed,it is generally pure until it comesinto direct contact with suchsurfaces as the evaporator coils,condensate pans, and drain lines.It is from these surfaces thatcondensate will come into contactwith dust, debris, bacteria, etc.

Condensate drain pans arecharacteristically located in areaswith very little light and offer amoist and warm breeding groundfor bacteria and the productionof bacterial slime. This slime canultimately cause blockages tooccur in the condensate drainlines, resulting in water damage

to homes and buildings.In residential settings, it is

important to change the air con-ditioning filters regularly. Thiswill help to keep the evaporatorcoils clean and help reduce thepotential for bacterial growth.

It is also important to keepyour condensate drain line clean.To clean the condensate drain line,you will first need to turn off yourair conditioner and disconnect thedrain line from the condensatedrain pan. You can clean out thehose by pouring a vinegar-wateror bleach-water solution down thehose and letting it drain normally.This will help to kill fungus grow-ing inside the hose and reduce therisk of blockages.While youmay beable to do this yourself, it is high-ly recommended that you use theservices of a trained professional.

In commercial and industrialsettings, accessing the condensatedrain pans is often easier. In thesesettings, it is recommended thatthe pans be kept free of dirt anddebris by regular cleaning and theaddition of biocide tablets to thecondensate within the drain pans.

One concern that deservesspecial attention when dealingwith condensate is the possiblepresence of microbial pathogens.Condensate is generally createdin the presence of moisture andwarmth. Condensate drain pansare often prime breeding groundsfor bacteria. If condensate isallowed to stagnate and becomewarm in a cooling system, it can

192 | Design for Water

Page 212: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

lead to favorable growth conditionsfor bacteria, including legionellapnuemophila bacteria that are thecause of Legionnaires’ disease.Although legionella pnuemophilais commonly found in a varietyof natural and man-made aquat-ic environments, it can become apublic health threat if water con-taining the bacteria is atomizedand inhaled. Atomization willoccurs when a liquid is sprayedunder pressure, creating a mist.This can occur under such appli-cations as landscape irrigation.

As the saying goes, “It isbetter to be safe than sorry.” Ifyou are going to collect andreuse condensate for any pur-pose, it is always a good idea to

ensure some type of treatmentthat will help to reduce the riskof microbial growth. This canoften be easily done by the addi-tion of a small amount ofchlorine. It is highly recom-mended that you use the servicesof a trained professional when itcomes to water treatment.

Following are a few case studiesthat shown how air-conditioningcondensate is being safely collect-ed and reused. These examplesalso use very little chemical filtra-tion in their individual systems.Mixing of rainwater and air con-ditioning condensate with coolingtower blowdown water may alsobe one way to dilute the coolingtower chemical build-up.

Case Studies | 193

CASE STUDY: T.C. WILLIAMS HIGH SCHOOL—RAINWATER, AIR CONDITIONINGCONDENSATE, AND COOLING TOWER BLOWDOWN WATER

Moseley Architects designed a461,000 square-foot, three-storybuilding with a 450,000-galloncistern for the T.C. Williams

High School in northernVirginia. The cistern is locatedunder the school’s parkinglot and collects rainwater,

Location: Alexandria, Virginia

Type of system: Active multiple water collection

Year installed: 2004

Containment: Below-grade, 450,000-gallon concrete cistern under parking lot

Water usage: Toilets, landscape irrigation, roof garden, and cooling towermake-up water

Contact: Moseley Architects, Richmond, Virginia www.moseleyarchitects.comHensel Phelps Construction CompanyAlexandria City Public Schoolswww.acps.k12.va.us

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194 | Design for Water

MOSELEYARCHITECTS,HENSELPHELPSCONSTRUCTION,

ANDCITYOFALEXANDRIA

MOSELEYARCHITECTS,HENSELPHELPSCONSTRUCTION,

ANDCITYOFALEXANDRIA

View of interiorcistern ceiling andfloor at completion

Covered above viewof the cistern location

MOSELEYARCHITECTS,HENSELPHELPS

CONSTRUCTION,A

NDCITYOFALEXANDRIA

MOSELEYARCHITECTS,HENSELPHELPS

CONSTRUCTION,A

NDCITYOFALEXANDRIA

TOP LEFT:Cistern floor during

constructionTOP RIGHT:

Cistern wallsgoing up

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stormwater, air-conditioningcondensate, and cooling towerblowdown water for reuse inthe school’s toilets, irrigationsystems, and cooling tower

make-up water requirements.It required close collaborationbetween all designers and theCity of Alexandria.

Case Studies | 195

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Integrated Water Systemschematic for the T.C.Williams High School

CASE STUDIES:ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY (ADEQ), ARIZONADEPARTMENT OF ADMINISTRATION (ADOA), AND MOHAVE COUNTYADMINISTRATION BUILDING (MCAB)COOLING TOWER BLOWDOWN WATERThe OPUS Corporation hasdesigned and installed three

cooling tower blowdown watercollection systems. Two systems

HEATHERKINKADE-L

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ADEQbuilding

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196 | Design for Water

Location: Phoenix and Kingman,Arizona

Type of system: Active alternate water collection

Year installed: 2004-2005

Containment: Below-grade, 7,200 gallonfiberglass cistern

Water usage: Landscape irrigation

Contact: Opus West ManagementCorporation, Phoenix, Arizonawww.opuscorp.com

OPUSW

ESTM

ANAGEMENTCORPORATION

OPUSW

ESTM

ANAGEMENTCORPORATION

TOP:ADEQ tank connection

to equipmentBOTTOM:

ADEQ tankin ground

ADEQ buriedtank

OPUSW

ESTM

ANAGEMENTCORPORATION

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Case Studies | 197

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ADEQ equipmentvault

HEATHERKINKADE-L

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Cooling tower watercollection pipe

HEATHERKINKADE-L

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Coolingtower

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198 | Design for Water

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OPUSW

ESTM

ANAGEMENTCORPORATION

SOURCE:A

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ADOABuilding

Mohave CountyAdministration

building

BELOW:Integrated WaterSystem Plan for

the ADEQ, ADOA,and MCAB

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are located in Phoenix, Arizona,at the Arizona Departmentof Environmental Quality(ADEQ) and at the ArizonaDepartment of Administration(ADOA). The third system islocated in Kingman, Arizonawithin the Mohave County

Administration Building. Allthree systems are designed to besimilar to the ADEQ buildingsystem in Phoenix. Coolingtower blowdown water is collect-ed and reused without anychemical additives for on-sitelandscape irrigation.

Case Studies | 199

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Cistern Schematic forthe ADEQ, ADOA,and MCAB

FOG COLLECTION: AN ALTERNATE WATER SUPPLY

There is a small beetle—theNamib Desert beetle—thatwakes up every morning, justas the fog rolls in, to spread itswings into the air. The beetle iscatching its only drink of theday. The light fog condenses onthe beetle’s back and rolls downinto its mouth.44 This seeminglysimple process is the beetle’sonly chance for survival in itsharsh environment. Humansliving in the same or similarenvironment are not so lucky.

Fog collection attempts bio-mimicry by placing arrays of fog-collecting screens in the air, similar

to the way the beetle extends itswings, to allow fog to condenseon the mesh screening and rundown the screen to a trough thatdirects the condensate into themouth of a water tank, where thewater waits to be used. Typicallywind and rain are unwanted, but insome areas of the world, they offerthe only opportunity for collectionof large amounts of water. Inareas where the rain is too lightto fall from the sky, it must begiven the opportunity to forminto larger droplets that can falland be collected. Fog collectiontakes advantage of this process.

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200 | Design for Water

FOGQUEST

FOGQUEST

FOGQUEST

Fog mesh with fog inthe background and

flower in the foreground,Guatemala

Fog collectors andtank in Guatemala

Double-mesh fogcollector and troughbelow to catch the

condensate

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The amount of fog water thatcan be collected depends on thefog’s liquid water content, fogdroplet size, wind speed, the effi-ciency of the mesh used in the fogcollector, and the surface area ofmesh installed.45 When collectingwater from the atmosphere it isvital to know whether the collectedwater is to come from fog, rain, ordrizzle. The techniques for collect-

ing each droplet size are different.However, fog collection is a veryviable water catchment techniquein areas where fog forms and watersupplies are low or nonexistent.Many communities throughoutthe world are existing proof thatfog collection works; fromGuatemala to Nepal, fog collectionhas enhanced the quality of lifefor people living in those areas.

Case Studies | 201

FOGQUEST

TOP:Child fetching waterfrom a FogQuestNepal water tankBOTTOM:Typical fog collectorschematic

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CASE STUDY:NEPAL WATER FROM FOG PROJECT—FOGQUEST COLLECTION SYSTEM

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GREYWATER COLLECTION: AN ALTERNATE WATER SUPPLY

Greywater—or graywater—isdefined as untreated householdwastewater specifically from non-kitchen sinks, showers, baths,and washing machines or laundrytubs. It does not include waterfrom kitchen sinks, dishwashers,or toilets; these sources fallunder the heading of black wateror sewer water. Greywater is typ-ically only used for landscapeirrigation or toilet flushing, andin some states its use and appli-cation are regulated to limithuman exposure to the water.There are a few rules to follow indealing with greywater as follows:

• Do not use in vegetable gar-dens to irrigate root crops oredible parts of food crops thattouch the soil; its applicationto fruit trees has been listed asbeing safe

• Overflows from storage unitsshould drain to a sanitarysewer or septic system

• Use stored greywater withintwenty-four hours to preventbacteria growth

• Only discharge in areas thathave more than five feet of soilto the groundwater table

• Keep systems out of areas proneto flooding (to reduce transportpotential of pollutants)

• Laws typically require grey-water to be used on the samesite where it is generated

• Subsurface irrigation is typi-cally required to minimizeexposure; no spray or floodirrigation should be allowedwith greywater

• Greywater should not be dis-charged to a water-course ofany type

There are examples of com-mercial projects using greywaterin a safe and efficient manner; itis not limited to a residentialalternate water source. Somegreywater applications can beimplemented through fixturesthat exist today, such as the Totohand- wash cascade toilet. Ahand-washing bowl collects aportion of the tank refill for usein flushing the toilet. When fix-tures like the cascade toilet areused in the initial design, costsare low. Retrofits always costmore than placing the option ina new design. Greywater storagetanks are the largest cost in agreywater system. A greywatercollection system cost can rangefrom a retrofit of $1,250 to anew construction cost of $650.Prices vary greatly and dependon a multitude of factors. In anysituation, greywater collection isa viable alternate water source.

Sources:“Using Gray Water in New

Mexico’s ResidentialLandscapes,”

202 | Design for Water

Location: Danda Bazzar, Nepal

Type of system: Passive water collection

Year installed: 1997

Containment: An array of six large fog collec-tors (19.7 by 39.3 ft.) tosupply fifteen households—over80 people—with fresh waterfor several months; water isstored in three separate 265-gallon tanks

Water usage: Potable water supply (plans areto build a 6,600-gallon tank toallow more homes to benefit)

Contact: FogQuest: Sustainable WaterSolutions, Canadawww.fogquest.org

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www.nmenv.state.nm.usOasis Design web site,

www.oasisdesign.netPATH Technologies web site,

www.nahbrc.org“Arizona Graywater Guidelines,”

www.watercasa.org

California Graywater GuideUsing Graywater in YourHome Landscape,www.owue.water.ca.gov/docs/graywater_guide_book.pdf

“Yarra Valley Water Grey WaterReuse Fact Sheet,”www.yvw.com.au

Case Studies | 203

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THECALIFORNIAGRAYWATERGUIDE,

USINGGRAYWATERINYOURHOMELANDSCAPE;G

RAYWATER

GUIDE,1995

Typical residentialgreywater system

CASE STUDY:NATURAL RESOURCES DEFENSE COUNCIL—RAINWATER AND GREYWATERCOLLECTION SYSTEM

The Natural Resources DefenseCouncil’s (NRDC) Santa Monicaoffice opened in 2003 as a build-ing designed to take advantageof green building techniques.The site was purposely chosento take advantage of existingservices and utilities. The build-ing was redesigned to conservewater and energy as well asshowcase environmentally soundmaterials. The NRDC supports

greywater reuse and rainwatercollection, both of which aretechniques used at the SantaMonica building. The buildinguses a bamboo-planted cisternto help filter the rainwaterwhich is then mixed with thebuilding’s greywater for reuse inthe toilets. The greywater/rain-water mixture is also used toirrigate roof level and groundlevel landscapes.

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204 | Design for Water

Location: Santa Monica, California

Type of system: Greywater collection

Year installed: 2003

Containment: Greywater system is based on anEquaris Infinity water treatmentsystem, which settles and aeratessink and shower water as wellas the rainwaterStormwater system consists oftwo custom-built cisterns beneathbamboo planters that captureand prefilter stormwater fromthe roof, 800 gallons per day

Water Usage: Toilets and landscape irrigation

Contact: Natural Resources Defense Councilwww.nrdc.orgEnvironmental Planning andDesign LLCwww.epd-net.comEquaris Corporationwww.equaris.com

NATURALRESO

URCESDEFENSECOUNCIL

NATURALRESO

URCESDEFENSECOUNCIL

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TOP:Front of the NaturalResources Defense

Council, Santa MonicaOfficeMIDDLE:

Greywater filtration tanksBOTTOM:

Rainwater, greywater,black water, and munici-pal water conceptualinteraction diagram

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Remote AreasWater CatchmentHuman-made water catchmentsfor wildlife have many names,including guzzlers, drinkerboxes, trick tanks, and concrete-apron catchments. Some human-modified and natural catchmentsare called potholes (human-made rock catch basins), tinajas(modified or completely naturalrock pools), springs, and wells.Wildlife water catchments areinstalled to attract wildlife forvarious reasons. They can beplaced to open up lands to graz-ing, lands that have not beengrazed due to a lack of watersources. These catchments canalso keep animals from having totromp through pristine riparianareas, allowing them to healfrom over use.

The catchments are typicallymobile structures that can berelocated if needed and can helpto re-establish wildlife that havepreviously left because ofdrought. The catchments canalso be removed easily. Human-made rainwater catchments canalso be specifically used toattract wildlife for observationpurposes, and can be locatedanywhere in any range or graz-ing area.

Guzzlers are water catch-ments that include a solidroof-like structure, a tank, a floatswitch, a trough, and gravity

feed. The roof structure can bebuilt in a butterfly fashion, witha low center and raised edges, orbuilt to have the entire roofplane tilt in one direction. Thestorage tanks—around 2,250gallons total—can be built underthe roof structure or at an adja-cent location and at a lowertopographic elevation to allowgravity to move the water to thestorage tank. From the tank apipe runs down hill as needed toa 2-foot-long sump box thatcontains a flow switch. Attachedto this sump is a shallow troughthat allows animals to drink; thetrough is refilled from the sumpbox when the water level lowers.Some troughs have sloped edgesto allow smaller animals such asbirds, turtles, rabbits, squirrels,and lizards to drink safely with-out the fear of drowning.

Human-made rainwatercatchment devices called tricktanks are typically made out ofgalvanized metal with invertedgalvanized metal umbrellas ontop. These inverted umbrellasextend out beyond the lip of thetank several feet and slope backto the center of the 1,500- to2,500-gallon tank so the rain-water drains into the tankdirectly. A pipe exits the tank atground level to fill a similarsump and drinking trough aspreviously described.

Case Studies | 205

Rainwater Harvesting for Wildlife

RAINWATER CATCHMENT FOR WILDLIFE

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Water catchments calleddrinker boxes are prefabricateddevices that when assembledin the field provide the samewatering capabilities as guzzlersand trick tanks. However, theirwater storage capacity is muchless. Drinker boxes are usuallyburied (or partially buried) toallow a low profile and lessvisual impact than the guzzleror trick tanks.

Concrete-apron rainwatercatchments are permanent, and,as all of the described wildlife

rainwater catchments describedpreviously, require very littlemaintenance. All of thesewildlife water catchment systemsare viable and valuable to thehumans building them and theanimals requiring them.

Sources:Harvesting Rainwater for

Wildlife, 2006, http://tcebookstore.org

Willborn Bros. Co., www.willbornbros.com

206 | Design for Water

CASE STUDY:CONCRETE RAINWATER CATCHMENT—RAINWATER CATCHMENT FOR WILDLIFE

The following photographsand details are rainwater col-lection techniques used forwildlife as discussed above.

They are found throughoutthe United States in remotelocations to help supply waterto the local wildlife.

Location: Typical System

Type of system: Passive stormwater collection offconcrete apron

Year installed: Not available

Containment: Below-grade storage tank approx3 feet wide by 16 feet long andinches deep.

Water usage: Wildlife water source

Contact: Texas Cooperative Extensionhttp://texasextension.tamu.eduWillborn Bros. Co.www.willbornbros.com

WILLIAMW

ARNER

Kaibab Guzzler –umbrella tank

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Case Studies | 207

BILLYKNIFFEN

Concrete catchmenttrough for wildlifedrinking

BILLYKNIFFEN

Raised “roof-like”catchment surface

BILLYKNIFFEN

Concrete catchment padfor collecting water

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208 | Design for Water

BILLYKNIFFEN

BILLYKNIFFEN

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Tank for guzzlerrainwater storage

Drinker box forguzzler water

BOTTOM LEFT:Typical concrete

pad for water collec-tion – plan

BOTTOM RIGHT:A cross-section of thetypical concrete pad,

tank, and trough

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Case Studies | 209

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LEFT:Typicaldrinker boxMIDDLE:A typical guzzlerroof detail

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Float boxcross-section

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210 | Design for Water

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TOP:Typical umbrella

guzzlerRIGHT:

Galvanized tank andfloat box plan

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THE PRECEDING chapters havedocumented and described

both the concepts and processesof rainwater catchment, storm-water collection, and alternatewater reuse. Common sense tellus there are limits to how muchwater communities can with-draw from underground aquifersand surface lakes or rivers tomeet their current needs withoutthreatening their futures. All ofthese water catchment, collec-tion, and reuse systems can help

offset the quantity of groundwa-ter or surface water withdrawnby replacing municipal potablewater as a source for non-potable water demands.

It is evident that we contin-ue, unrestrained, in our use ofwater. Waiting until tomorrow tosave will be too late— we needto begin now. Probably thebiggest deterrent to, as well asthe main virtue of, a rain-basedor alternate water-based systemis that it requires owners to pay

It is all about water.When we are unawareof, ignore, or arewasteful in our rela-tionship to the inter-action of water withother natural resources,water can become awaste product andpotentially a powerfulsource of destruction.

— Patchett and Wilhelm

Conclusion | 211

German bus washusing only rainwaterto wash vehicles

Conclusion

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close attention to where theirwater comes from and how it isused. Rainwater and stormwatercatchment systems offer ownersthe highest possible personalcontrol over a water source andits quality.

46

Alternate waterreuse provides a guaranteedwater supply that can also bemanaged and purified as needed.Despite the control afforded bythese water systems, the generalpublic seems to prefer paying amunicipality to supervise itswater supplies. Our apparentwillingness to pay for waterwithout question is probablydue to the following:

• Lack of knowledge and respectfor the true value of water

• Relatively inexpensive waterand services compared tohousehold incomes

• Deficient public awareness ofresource-sensitive developmenttechnologies such as rainwater,stormwater, and alternate watercatchment and/or collection

• Limited knowledge of the ben-efits of these water catchmenttechniques as an alternatewater source

• Concern about costs associat-ed with installing a watercatchment system

• Municipal unwillingness toaccept alternative flood-con-trol techniques involvingrainwater and stormwatercatchment

Education of both the publicand municipalities is slowlyoccurring, and the importanceand benefits of maintaining thehydrologic cycle has been proven

212 | Design for Water

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German bus washingand service building.All rooftop rainwaterrunoff is directedto undergroundstorage tanks

SOURCE:JOEW

HEELER,R

AINFILTERSOFTEXAS,LLC

Typical German WISYsystem that has

become commonpractice through edu-cation and necessity.

Flow calmingdevice

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in actual application of tech-niques—such as the SeattlePublic Utilities Natural DrainageSystem—and in controlled stud-ies. The University of Guelph inCanada has found permeablepavers of interlocking concreteblocks demonstrate a 90 percentreduction in runoff volume andthat they significantly reducesurface runoff pollutant loads.

47

Existing projects—as thosedescribed in Chapter 5, Case

Studies—demonstrate the actualpotential for water catchmentand reuse from rain storms andbuilding equipment. Severalplanned projects, and severalcurrently in construction, aredesigned to use all potential sitewater for reuse or infiltration.

One example of an in-con-struction project is the SidwellFriends Middle School located inWashington D.C., a buildingdesigned to earn a USGBC LEED

Conclusion | 213

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Rain-catching, shade-pro-viding, upside-downumbrellas in a courtyardof multiple commercialoffice buildings

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Patio and stormwaterswale below upside-down umbrellas

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Platinum rating. A constructedwetland will treat building waste-water on site and the treatedwater will be recycled back to thebuilding and its lavatories. A greenroof will hold and filter rainwateras well as grow vegetables andherbs for the schools cafeteria.On a larger scale, the DorranceH. Hamilton Building and Plazain Philadelphia, Pennsylvaniahas changed a formerly 7 per-cent pervious site into a 40percent pervious site. The build-ing will collect rooftop rainwaterrunoff and air conditioning con-densate in a 20,000-gallonbelow-grade cistern. The waterwill be used to irrigate the land-scaped roof of a below-groundvehicular parking structure.

Both of these smaller proj-ects are only the beginning, andthe concepts discussed in thisbook need to be combined withother sustainable techniques tocreate an ultimate urban designallowing humans to live closerto what natural cycles requirefor continuation. An exampleof a fully integrated project isthe Portland, Oregon project,

Lloyd Crossing. This project areaincludes a 35-block, inner-cityneighborhood and is plannedthrough a 45-year process.Habitat quality, quantity, andconnections will be restored.Rainwater, stormwater, greywater,and black water will be treatedand reused. Energy demands areplanned to be reduced, and on-site renewable-energy resourceswill be harnessed. These resourceswill include biogas, solar, andwind power. Carbon-neutralityis also planned through purchaseof carbon credits.

The site has been evaluatedfrom a pre-development wateruse condition to an existing wateruse condition to a future-plannedwater use condition. Groundwaterrecharge is planned to increasebeyond existing quantities, tran-spiration is planned to increase,and site stormwater runoff isplanned to be substantiallyreduced. Rooftop rainwater isplanned to be collected throughgreen roofs and bioswales. Thetreated black water and capturedrainwater are planned for flushinglavatories as well as landscape

214 | Design for Water

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Passive stormwatercollection: commercialoffice building with apermeable courtyard

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irrigation and infiltration. All ofthis information and more can befound on this project by searchingthe World Wide Web for LloydCrossing: Sustainable UrbanDesign Plan and Catalyst Project.

The Environmental ProtectionAgency ranks urban runoff andstorm-sewer discharges as thesecond most prevalent source ofwater quality impairment in ournation’s estuaries, and the fourthmost prevalent source of impair-ment of our lakes.

48

Many areas ofthe world do not even have watersupplies let alone fresh watersupplies. As a result of disasterslike Hurricane Katrina and itsdevastating effects on the majorcity of New Orleans, a water-harvesting machine was createdto turn air into water. The AquaSciences machine can create upto 1,080 gallons of drinkablewater from the atmosphere in aday.49, 50 The machine comes infour sizes. The smallest fits intothe back of a pickup truck. Thelargest fits into a 40-foot tractor-trailer, and includes non-electricgenerators.51 The water-harvest-ing machine works by pushingair through a liquid salt solutionof lithium chloride. The com-pound used in the machineattracts water molecules; it ishygroscopic in nature, whichmeans that it can be used to har-vest water in humid as well asarid regions. The water is even-tually extracted from the liquidsolution and is filtered through

table salt as a natural disinfec-tant.52 A final carbon filter isused to add taste. Harvestedwater from the machine is storedin extremely strong bags withspigots so the water can easily betransported. The bags block sun-light and resist bacteria growth,allowing the water to stay fresh.

A second machine, theWaterPyramid, has recentlybeen designed for less developedcountries. It is a hybrid waterinstallation that integrates alarge-scale solar distillation andrainwater-harvesting practices.More information on this system,developed in the Netherlands byAquaEst International, can befound at www.aquaestinterna-tional.com/waterpyramid.htm.Both the Water HarvestingMachine and the WaterPyramidare the result of desires to pro-vide potable water for areas thatlack clean water sources.

It has been determined bythe United Nation’s MillenniumEcosystem Assessment that weare “living beyond our means”and that the natural hydrologicalsystem is a key service providedby nature that has been weak-ened by human development.

Passive survivability, coveredby Environmental Building Newsin a May 2006 article, isdescribed as “a building’s abilityto maintain critical life-supportconditions if services such aspower, heating fuel, or water arelost.” This concept has been sug-

Conclusion | 215

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gested as a standard design crite-rion for all homes, apartmentbuildings, and assembly build-ings that may be used in timesof emergency. Most of these sit-uations can be remedied withthe catchment of or infiltrationof rainwater, stormwater, and/oralternate water. It is time todesign for water in all projects,at all levels— and just maybewe can learn to live with natureand maintain our water suppliesfor emergencies as well as forfuture generations.

Information for FurtherResearch and Contacts forSuppliesAgua Solutions International SA

Costa Rica rainwater harvestingconsultant, U.S. contact available.www.aguasolutions.com

American Water Works Association(AWWA) The AWWA is an inter-national nonprofit scientific andeducational society dedicated tothe improvement of drinking waterquality. www.awwa.org

American Rainwater CatchmentSystems Association (ARCSA)Association for the Advancementof Rainwater Harvesting.www.arcsa-usa.org

216 | Design for Water

SOURCE:W

WW.AQUAESTINTERNATIONAL.COM/

WATERPYRAMID.HTM

CATHYBACON,C

AMPALDERSG

ATE

TOP:WaterPyramid

BOTTOM:A 700-gallon cistern at

Camp AldersgateCommons Building inLittle Rock, Arkansas; apotential emergencyassembly building

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Ao SaraOffers a variety of rainchains andgives directions for making rain-chains. www.aosara.com

Aqua HarvestRainwater harvesting design andinstallation.www.aquaharvestonline.com

AquaEst InternationalRainwater purification systemsfrom Zwolle, the Netherlands.www.aquaestinternational.com/home.htm

BRAE - Blue Ridge Atlantic EnterprisesRainwater technology and equip-ment company.www.braewater.com/ICMS

Center for Maximum Potential BuildingSystemsA nonprofit sustainable design andappropriate technologies firmengaged in education, demonstra-tion, and research. www.cmpbs.org

Centre for Science and EnvironmentAn independent, public Indianinterest organization, which pro-vides several rainwater relatedpublications such as AWaterHarvesting Manual for UrbanAreas; Case Studies from Delhi:Drought? Try Capturing the Rain;and Dying Wisdom: Rise, Fall, andPotential of India’s TraditionalWater Harvesting Systems.www.cseindia.org

Cherry Blossom GardensJapanese garden supplies and orna-ments, including rainchains.

www.cherryblossomgardens.com

Contech Construction Products Inc.Offers corrugated metal pipeunderground detention/retentionfor large systems.www.contech-cpi.com

Darco IncorporatedDarco tankswww.darcoinc.com/septic-tanks.html

Demossing RoofsUniversity of Alaskawww.uaf.edu/coop-ext/publications/freepubs/HCM-04956.html

Desert Botanical Garden’s Desert HouseRainwater harvesting system inPhoenix, Arizona.www.dbg.org

Development Technology UnitDTU Roofwater HarvestingProgrammeSchool of Engineering, WarwickUniversity, UKwww.eng.warwick.ac.uk/DTU

Dharma Living Systems (Living DesignsGroup)Design and installation serviceswith emphasis on sustainability.www.livingdesignsgroup.com

Earthwrights DesignsRainwater technology and [email protected]

Fab-Seal Industrial Liners, Inc.Offers custom fabricated superiorliners for lining tanks holdingdrinking water. www.fabseal.com

Resources List | 217

Appendix A:Resources List

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Field Lining Systems, Inc.NSF/ANSI 61 Standard.www.greatwesternliner.com/potablewater.html

FogQuestFogQuest is a non-profit, registeredcharity dedicated to planning andimplementing water projects forrural communities in developingcountries. http://www.fogquest.org/

Forgotten Rain LLCHeather Kinkade-Levario’s rainwa-ter harvesting and stormwaterreuse company.www.forgottenrain.com

FRALO Plastech Mfg., LLCBlow-mold HDPE below-gradetanks. www.fralo.net

Gardener’s Supply CompanyRainbarrelswww.composters.com/docs/rainbarrels.html

Greywater Treatment Package Systemswww.pontos-aquacycle.com/pontos/en/company/pontos.htmlwww.watersavertech.comwww.ecoplay.nl/en/index.htmlwww.bracsystems.com/contact-us.html

Greenbuilder Sustainable BuildingSourcebookDeveloped by the Austin GreenBuilder Program, this sourcebook,available on the web, contains achapter on rainwater harvesting.www.greenbuilder.com/sourcebook/rainwater.html

Gutters Direct.comAnswers for all questions aboutgutters and downspouts.www.guttersdirect.com

Harvest H2ORainwater resourceswww.harvesth2o.com/

Heat Tapeswww.cpsc.gov/cpscpub/pubs/5045.htmlhttp://extension.missouri.edu/explore/agguides/agengin/g01408.htmwww.thermon.comwww.heatersplus.com/easy.htm

“How to Assemble Rain Barrels in thePacific Northwest Region”How to assemble rain barrels toconserve water, save on water bills,and provide for garden plants dur-ing drought, and also where to buythem.www.dnr.metrokc.gov/wlr/PI/rainbarrels.htmwww.dnr.metrokc.gov/wlr/PI/Pdf/cistern-water-saving.pdf

Hydros Group / Desert Rain SystemsConsultants for renewable watersources. www.thehydrosgroup.com

Innovative Water Solutions, IncA full-service water conservationplanning, design, and systeminstallation firm for commercialand residential projects.www.watercache.com

International Rainwater CatchmentSystems Association (IRCSA)Dedicated to the promotion andadvancement of rainwater catch-ment systems technology withrespect to planning, development,management, science, technology,research, and education worldwide.www.ircsa.org

Invisible Structures, Inc.Rainwater crates.www.invisiblestructures.com

Kitt Peak National ObservatoryAn entire water source from rain-water harvesting system.www.noao.edu/kpno

Lanka Rainwater HarvestingForum/Roofwater HarvestingResearch GroupAims to organize a network to col-lect and share experiences inrainwater harvesting within SriLanka. Four-partner internationalresearch program, funded by theEuropean Union and started in1998.www.rainwaterharvesting.com

Leaf Beater SystemsAn Australian company that spe-cializes in water catchment andstorage systems and leaf debrisremoval systems.www.leafbeater.com

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LeafGuardSeamless gutter protection system.www.leafguard.com

LeafslideLeaf and debris filter inline withdownspout.www.rainharvesting.com.au

Low Impact DevelopmentInformation and resources on low-impact development.www.lowimpactdevelopment.orgwww.goprincegeorgescounty.com

National Sanitation FoundationA nonprofit organization whoseWater Distribution SystemsProgram certifies methods for thetreatment of drinking water.www.nsf.org

Northwest Water SourceRainwater harvesting design, con-struction, and component supplycompany for residential and com-mercial [email protected]

Oasis Design ConsultingA home-based design and publish-ing business providing rainwaterharvesting information.www.oasisdesign.net/water/rainharvesting/index.htm

Ozotech, Inc.Ozone Filtration Systems.www.ozotech.com

PermacultureRainwater harvesting for drylands.www.harvestingrainwater.com

Pima County Flood Control DistrictLink to water-harvesting manualand other references.www.dot.co.pima.az.us/flood/wh/index.html

PioneerWater Tanks (Australia 94) Pty LtdRainwater equipment, US contactavailable. www.pwtaust.com

Rainchains.comQuality rainchains and gardenaccents. www.rainchains.com

Rainfilters of Texas, LLCFactory-authorized distributors forWISY filter systems.www.rainfilters.comwww.wisy.de/eng/eng/products.htm

Rain Harvesting Pty. Ltd.Rainwater equipment and technol-ogy supplier.www.rainharvesting.com.au

Rain KingRainbarrels.www.rainwatersolutions.com

Rainwater Collection Over TexasSales, service, systems, and supplies.www.greenbuilder.com/sourcebook/Rainwater.html

Rainwater Management SolutionsRainwater Management Solutionsprovides rainwater harvesting sys-tems for residential andcommercial applications.www.rainwatermanagement.com

Rainwater Recovery Systems, LLCSmart solutions for water manage-ment.www.rainwaterrecovery.com

Rain Gardens in Connecticut: A DesignGuide for Homeowners.A residential design guide for raingardens.University of Connecticutwww.sustainability.uconn.edu/

RainsaverRainbarrels.www.rainsaverusa.com

Rocky Mountain InstituteArticle and contacts on rainwaterharvesting.

www.rmi.org/sitepages/pid287.php

SafeRainWater diverters.www.saferain.com.au

Save the Rain“Save the Rain is an independentnonprofit and is not affiliated withany religious organization. We aresimply a group of regular peoplewho decided that the present waterconditions in the world are unac-ceptable and we came together tochange it.” www.savetherain.org.

Spec-All Products, Inc.Metal tank supplier and installer.www.specallproducts.com

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StormceptorThe Stormceptor System CD-ROMuser’s guide.www.stormceptor.com

Suntree TechnologiesNutrient-separating baffle box.www.bafflebox.com

Tank TownRainwater collection. Collect rain-water, filter it, and enjoy the finestand healthiest water in the home.www.rainwatercollection.com/

Texas Guide to Rainwater HarvestingTexas Water Development Board’scomprehensive manual on rainwa-ter harvesting.www.twdb.state.tx.us/publications/pub.asp

Texas Metal CisternsExperts for design, installationand service of rainwater collectionsystems.www.texasmetalcisterns.com

Timber TanksSelling aesthetically pleasing wood-en potable water tanks.www.timbertanks.com

ToolBase ServicesRainwater harvesting technologyinventory (search for RainwaterHarvesting).www.toolbase.org/

Tucson, City of, Water HarvestingGuidance Manual.This manual describes a processfor evaluating site characteristicsand for developing integrateddesigns in which water harvestingenhances site efficiency, sustain-ability, and aesthetics. Waterharvesting principles, techniques,and configurations are described,followed by example designs for asubdivision, commercial site, pub-lic building, and public

right-of-way.http://dot.ci.tucson.az.us/stormwater/education/waterharvest.htm

University of Arizona Water ResourcesResearch CenterAcademic water-related informa-tion with link to WaterConservation Alliance of SouthernArizona (CASA).www.ag.arizona.edu/azwater

University of Hawaii“Rainwater Catchment Guidelines”www.ctahr.hawaii.edu/oc/freepubs/pdf/RM-12.pdf

University of Newcastle Upon TyneA site search will bring several arti-cles on rainwater harvesting.www.ncl.ac.uk

Water MagazineA site search will bring several arti-cles on rainwater harvesting.www.watermagazine.com

Water Tanks.comSupply company for potable andnonpotable water tanks.www.watertanks.com

Wonder Water Rain Water CatchmentWonderwater has one objective: tocreate a supplemental supply ofwater so we will continue to haveenough to drink, wash, cook, grow,and play in. We accomplish ourgoal with a 3,000-year-old prac-tice—catching, storing and usingthe rain.www.wonderwater.net

3P Technik UK LimitedRainwater equipment, US contactavailable.www.3ptechnik.co.uk

2020 EngineeringRainwater and stormwater solu-tions.www.2020engineering.com

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Here are some handy conversions for measurements:If you know: Multiply by: To Find:

Inches 25.4 millimetersInches 2.54 centimetersFeet 0.3048 metersYards 0.9144 metersMiles 1.609 kilometersFluid ounces 28.4 millilitersGallons 4.546 litersOunces 28.350 gramsPounds 0.4536 kilogramsShort tons 0.9072 metric tonsAcres 0.4057 hectaresSquare inches 6.452 square centimetersSquare yards 0.836 square metersCubic yards 0.765 cubic metersSquare miles 2.590 square kilometers

Millimeters 0.039 inchesCentimeters 0.39 inchesMeters 3.281 feetMeters 1.094 yardsKilometers 0.622 milesMilliliters 0.035 fluid ouncesLiters 0.220 gallonsGrams 0.035 ouncesKilograms 2.205 poundsMetric tons 1.102 short tonsHectares 2.471 acresSquare centimeters 0.155 square inchesSquare meters 1.196 square yardsCubic meters 1.307 cubic yardsSquare kilometers 0.386 square miles

Metric Conversion Tables | 221

Appendix B:Metric Conversion Tables

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Glossary | 223

Acre-foot (a.f.) – The amount of waterneeded to cover an acre of land onefoot deep. Equal to 325,851 gallons.

Aerobic zone – An area that supportsorganisms that exist only in thepresence of oxygen.

Algae – Aquatic one- or multi-celledplants without true stems, roots, orleaves but containing chlorophyll.Algae can produce taste and odorproblems in stored rainwater.

Alluvium – Debris from erosion, con-sisting of some mixture of clayparticles, sand pebbles, and largerrocks. Usually a good porous stor-age medium for groundwater.

Anaerobic zone – An area that supportsorganisms that are active in theabsence of free oxygen.

Aquifer – One or more geologic forma-tions containing enough saturatedporous and permeable material totransmit water at a rate sufficientto feed a spring, or for economicextraction by a well.

Aquifer compaction – The compressionof soil that occurs when soil parti-cles fall closer together because ofdiminished space between them: aresult of the withdrawal of aquiferwater that fills the voids betweengrained soil sediment.

Arid or semi-arid environment – Areasin which the ratio of annual pre-cipitation to evapotranspirationfalls within the range of 0.05 to0.65 percent. Excludes polar andsub-polar regions.

Artificial recharge – The act of deliber-ately adding water to a groundwateraquifer. Artificial recharge can beaccomplished by injection wells,spreading basins, or in-streamprojects.

Augmentation – Supplementation ofthe water supply by the importa-tion of water from another supplysource such as a municipal waterservice or from a basin or othersource of stored water. Alsoreferred to as alternate water sup-ply or make-up water.

Chlorine – A chemical commonly usedto disinfect water. It is highly effec-tive against algae, bacteria, andviruses, but not protozoa.

Cistern – A facility for storing water. Acistern must be closed and placedunderground or made of a materi-al that will prevent sunlight fromreaching the stored water.

Coliform bacteria – A common bacte-ria, found in soil and water, thatgrows in the intestines of warm-blooded animals. Generally notharmful, but high levels may indi-cate the presence of other harmfulbacteria or viruses.

Cone of depression – A drop in thewater table around a well or wellsthat have been pumping ground-water. Depending on the rate ofpumping and aquifer characteris-tics, a cone of depression can beshallow and extend only a few feet,or it can extend for several miles.Since water flows downhill under-

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ground, a cone of depression pullswater from the surrounding area,affecting adjacent water tables.

Debris – Any large items that could cloga rainwater system, specificallypumps and irrigation emitters.Debris may include leaves, branch-es, trash, or cigarette butts.

Desalinization – The process of remov-ing salts and other dissolvedminerals from water.

Diversion – A channel that diverts waterto sites where it can be used or dis-posed of through a stable outlet.

Drip irrigation – The application ofwater directly to the root zone of aplant at a rate slow enough to allowthe soil to absorb it without runoff.

Dry well – A large infiltration trench forrunoff, typically a vertical trenchor narrow hole covered with a filterfor debris and oil.

Effluent – A liquid that enters the envi-ronment from a point source suchas a sewage treatment or industrialplant.

Erosion – Detachment and movementof rocks and soil particles by gravi-ty, wind, and water.

Evaporation – The changing of a liquidto a gas.

Evapotranspiration – The amount ofwater transpired by vegetationthrough pores and evaporated.

Filtration – The process of passingwater through porous material tostrain out particles. Filtration canremove microorganisms, includingalgae, bacteria, and protozoa, butnot viruses.

First-flush device – A container that col-lects and disposes of the initial rainthat falls on a catchment surface,removing both debris and solublepollutants.

Fissure – A tear in the earth’s crust dueto land subsidence.

Flocculation – The clumping of particlesin water that collide because they fallat different rates. The larger parti-cles that form fall or settle morequickly than the original particles.

Floodplain – The area near a water-course that becomes inundatedduring floods. A 100-year flood-plain is one that would beinundated by a flood that has aone-in-one-hundred probability ofoccurring in any year.

Foul flush – A first flush that has beenallowed to stand, causing the accu-mulated debris to rot, which resultsin polluted and stinking water.

GPCD (Gallons per capita per day) –The average amount of water usedby an individual each day. TotalGPCD is calculated by dividingtotal water use in an area, includ-ing industrial and commercialuses, by the number of users.Residential GPCD is calculated inthe same way, but only consideringdomestic water use.

Greywater – Water that is collected frombaths, showers, washing machines,and sinks (water from kitchensinks is not allowed to be treatedlike rainwater).

Groundwater – The water that fills orsaturates the spaces between soilparticles and throughout porousbedrock such as limestone, sand-stone, or basalt.

Groundwater basin – An area enclosinga relatively distinct hydrologic areaof related bodies of groundwater.

Hydrologic cycle – The continual move-ment of water between the earthand the atmosphere through evap-oration and precipitation.

Infiltration rate – The rate at which soilwill absorb water. Expressed ininches per hour.

Irrigation district – A political entitycreated to secure and distributewater supplies. Some irrigationdistricts have departed from theiroriginal purpose of providing waterfor farm irrigation and now prima-rily serve municipal customers.

Land subsidence – The lowering of theearth’s surface due to compactionin aquifers that results from thelowering of the water table.

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Municipal water use – All non-irriga-tion uses of water supplied by acity, town, private water company,or irrigation district. Municipalwater use encompasses domestic,commercial, public, and someindustrial uses.

Nanofiltration (NF) — A form of filtra-tion that uses membranes withlarger pores than reverse osmosis(RO) filtration. NF removes mostsalts, pathogens, and organics. LikeRO, the process requires pre-treat-ment of water with chemicals or asand-based system. NF has notbeen used commercially on a largescale for drinking water.

Natural recharge – Natural replenish-ment of an aquifer from sourcessuch as snowmelt and storm runoff.

Overdraft – That quantity of waterpumped in excess of the replenish-able supply or the act of drawingfrom a water supply or aquifer inamounts greater than replenish-ment. Also, the sustained extractionof groundwater from an aquifer ata rate greater than its recharge rate,resulting in a drop in the level ofthe water table.

Paradigm – A way of thinking aboutand analyzing problems that hasbecome a standard.

Particulates – Solid particles or liquiddroplets suspended or carried inthe air.

Parts per million (ppm) and parts perbillion (ppb) – A measure of theconcentration of materials in a liq-uid, often used to describe thedegree of contamination of water.One ppm indicates that for eachone million units of water there isone unit of the contaminant. Oneppb indicates that for each one bil-lion units of water there is one unitof the contaminant. 1 ppm isapproximately equal to 1 mg/L.

Percolation – The downward movementof water in soil.

Permeability – A measure of the relativeease with which a porous medium

can transmit a liquid under apotential gradient.

pH – A number from 1 to 14 used todesignate the acidity or alkalinityof a soil. Below 7 is increasinglyacid, 7 is neutral, and above 7 isincreasingly alkaline.

Potable water – Water that is fit forhuman consumption.

Primary treatment – Initial treatmentgiven to sewage, usually involvingthe removal of solids and possiblysome disinfection. Precedes sec-ondary and tertiary treatments.

Rain – Water that falls as precipitationfrom clouds in the sky. Consideredthe first form of water in thehydrologic cycle.

Recharge – Augmentation of groundwater.

Reclaimed water – Water that was usedand then purified to a tertiary-treatment level, which allows it tobe used on turf or certain otherfacilities.

Renewable natural resource – A sourceof energy that can be replenishedin a short period of time.

Reservoir – A facility for storing water. Areservoir may be open or covered.

Reverse osmosis (RO) – A process where-by water is forced though porousmembranes that filter out solids.RO removes microorganisms,organic chemicals, and inorganicchemicals, producing very purewater. However, the process rejectsmore water than it filters.

Runoff – Drainage or flood dischargethat leaves an area as either surfaceor pipeline flow.

Secondary treatment – The most com-mon level of treatment of sewage,involving removal of solids, use ofbacterial action for purification,and the addition of disinfectants.Follows primary treatment andprecedes tertiary treatment.

Sediment – Soil particles and mineralsthat are washed from land into anaquatic system as a result of natu-ral and man-made activities.

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Sewage – Water that has been used byindividuals or businesses.

Sewer – A pipeline used to transportsewage to a treatment facility.

Soft water – Water with relatively lowconcentrations of certain dissolvedminerals, principally calcium, mag-nesium, and iron. Water fromwhich these minerals have beenmostly removed, usually through anion-exchange process. Rainwater.

Subsurface water – All water below theland surface, including soil mois-ture, capillary fringe water, andgroundwater.

Surface water – Water that flows on thesurface of the land.

Soil – A naturally occurring mixture onthe earth’s surface of minerals, organ-ic matter, water, and air that has adefinite structure and composition.

Swale – Low areas of land designed intoa landscape that capture water andallow it to infiltrate instead of run-ning off the property.

Tertiary treatment – Treatment of waterin order to improve its quality tothe point where it can be put to aparticular beneficial use. Followsprimary and secondary treatment.

Tinaja – A naturally existing rock bowlwhere rainwater collects.

Tohono O’odham – Native Americantribe located in south central andsouthwestern Arizona.

Total dissolved solids (TDS) – A meas-ure of the minerals dissolved inwater. Up to 500 ppm is consideredsatisfactory: A level above that isincreasingly unsuitable for domes-tic use.

Toxic – Describes substances that cancause injury or death when eaten,absorbed through the skin, orinhaled into the lungs.

Turbidity – The reduction of trans-parency in water due to thepresence of suspended particles: acloudy appearance in the water.Increased turbidity raises the riskof water-borne pathogens growingand reproducing. Because of this,turbid water is more difficult todisinfect.

Underground storage systems – Anyvessel located beneath the surfaceof the earth, such as a watertightconcrete tank or corrugated metalpipe, that is useful for holdingwater.

Urban – An area that has developed abuilt environment beyond the nat-ural carrying capacity of the land.

Water table – The upper boundary of afree groundwater body, at atmos-pheric pressure.

Well – A man-made opening in theearth through which water can bewithdrawn, with certain excep-tions, e.g.: as described in Arizonastate law ARS §45-402 (43).

Xeriscape (pronounced “zeer-ih-scape”)– A water-efficient landscapedesign that makes use of low-water-use plants.

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1 Millennium Ecosystem AssessmentBoard. 2005. Living Beyond OurMeans: Natural Assets and HumanWell-Being. United Nations.

2 Chapagain, A. K. and A.Y. Hoekstra.2004.Water Footprints of Nations,Volume 1: Main Report. UNESCO-IHE Value of Water Research ReportSeries No. 16. Delft, Netherlands.

3 Falkenmark, M. and J. Rockstrom.2005. Rain: The Neglected Resource.Swedish Water House Policy BriefNr. 2. SIWI.

4 See 3.5 Little, Val. 2003. GraywaterGuidelines. The Water ConservationAlliance of Southern Arizona:Phoenix, Arizona.

6 Gould, John and Erik Nissen-Petersen. 1999. Rainwater CatchmentSystems for Domestic Supply, Design,Construction and Implementation.South Hampton Row, London:Intermediate TechnologyPublications Ltd.

7 Pacey, Arnold and Adrian Cullis.1996. Rainwater Harvesting, theCollection of Rainfall and Runoff inRural Areas. Southampton Row,London: Intermediate TechnologyPublications.

8 Wahlin, Lars. 1997. Ethnic Encounterand Culture Change, ed. Sabour andVikor. 1997: 233-249.

9 See 8.10 Winterbottom, Daniel.

2000.“Rainwater harvesting, anancient technology—cisterns—is

reconsidered.” LandscapeArchitecture. April 2000: 40-46.

11 See 6.

12 See 10.

13 See 6.

14 Wilson, Alex. 1997.“RainwaterHarvesting.” Environmental BuildingNews. May 1997: 1, 9-13.

15 Boers, Th.M. 1994. RainwaterHarvesting in Arid and Semi-AridZones. Publication 55. Wageninge,the Netherlands: InternationalInstitute for Land Reclamation andImprovement.

16 Schemenauer, Robert S., PilarCereceda, and Pablo Osses. 2005. FogWater Collection Manual. FogQuestand Margarita Canepa: Thornhill,Ontario.

17 Texas Water Development Board.2005. The Texas Manual onRainwater Harvesting, Third Edition.Austin, Texas.

18 Centre for Science andEnvironment. 2000. AWaterHarvesting Manual For Urban Areas,Case Studies From Delhi. Faridabad,India: Age of EnlightenmentPublishers.

19 Manson, D. Brett. 2001. ReducingMixing Effects in Water Storage Tanks.www.eng.warwick.ac.uk/DTU/pubs/rn/rwh/uqpoo2_mason.pdf (15 Sept.2002).

20 Banks, Suzy and Richard Heinichen.1999. Rainwater Collection for theMechanically Challenged. DrippingSprings, Texas: Tank Town Publishing.

Notes | 227

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21 See 17.

22 Agua Del Sol International. 1998.Water Line. www.zekes.com/~aguadelsol/waterline.htm (27 April 2001).

23 Roofwater Harvesting ResearchGroup. Styles of RoofwaterHarvesting. www.eng.warwick.ac.uk/DTU/rainwaterharvesting/stylesofr-wh.html (10 November 2000).

24 Hartung, Hans. 2002. The RainwaterHarvesting CD. Weikersheim,Germany: Margraf Publishers.

25 Buttle, Mark, Michael Smith, andRod Shaw. Unknown. Technical BriefNo. 62. Emergency Water Supply inCold Regions.Water and EnvironmentalHealth at Loughborough (WELL),Loughborough University:www.lboro.ac.uk/well/ (18 August 06).

26 Barr Engineering Co. 2001. UrbanSmall Sites BMPs for Cold Climates.Bar Engineering: Minnesota CouncilEnvironmental Services, Minnesota,USA.

27 See 26.

28 See 25.

29 See 25.

30 See 25.

31 See 25.

32 See 25.

33 See 25.

34 Pope, Tim (Northwest Water Source).2002. Interview with author.

35 AquaEst International. 2004.Personal communication fromowner Willem P. Boelhouwer: [email protected].

36 See 17.

37 Beers, Stephen K. 1998. “SourcingWater from the Sky.”www.edcmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,4120,19385,00.html (15March 2001).

38 See 6.

39 Program on ConservationInnovation at the Harvard Forest.2004. The Report on ConservationInnovation. Fall 2004. Belmont,Maine: Harvard University.

40 See 39.

41 Ford Motor Co., 2005. “Ford RougeVisitor Center.”www.ford.com/en/company/about/sustainability/2005-06/envReviewBuildingsLEED.htm#frvc (3November 2006)

42 McKenzie, Heidi and MarkE.Holland. 2004. “Sustainable StormWater Management at the FordRouge Complex RedevelopmentSite.” Internal paper.

43 Lenntech.Water recycling for coolingpurposes by means of a cooling tower.www.lenntech.com/water_reuse_cooling_process_bymeansof _cooling_tower.htm (3 January 2006).

44 Trafton, Anne. 2006. “Beetle SpawnsNew Material.” MassachusettsInstitute of Technology: Internetnewsletter http://web.mit.edu/newsoffice/2006/beetles-0614.html (18August 2006).

45 See 16.

46 See 37.

47 Kelly, Stephen. “Rainwater Recyclingand Ecology – A Basis For Planningand Design.” Landscape Architectureand Specifier News: November 2005.

48 See 47.

49 American Observer. “FloridaCompany Unveils Disaster-Relief Toolthat Plucks Drinking Water fromDry Air.” The American UniversitySchool of Communication’sGraduate Journalism Program.www.americanobserver.net/2006/10/05/florida-company-unveils-disaster-relief-tool-that-plucks-drinking-water-from-dry-air/

50 Stevenson, John, Time for Kids,World Report Edition, December 8,2006. Vol. 12 No. 12, New York, NewYork.

51 See 49.

52 See 49.

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Aacequia, 125

Agua Solutions International SA, 216

air conditioning condensate, xvi, 3, 99,185, 188, 192-193, 214collection of, 178, 181, 195production of, 185-186, 189reuse of, 182-183, 193

Air Conditioning Condensate Guidebook,The, 182-183

air conditioning systems, 156, 179, 184-185, 187, 192

air handlers, 184, 187, 189

Alaskan Building Research Series HCM-01557, 44-45

alternate water supply, xiv, xvi, 2, 15, 28,35-36, 39, 63, 85, 87, 99, 181, 199,202, 212, 216collection systems for, xiv, 181for reuse, xi, xii, 4, 211-212

American Honda Northwest RegionalFacility, 139-140, 142

American Institute of Architects, 149

American Rainwater Catchment SystemsAssociation (ARCSA), xi, 216

American Water Works Association(AWWA), 216

Animal Services Division (GrandPrairie, TX), 128

Annan, Kofi, 1

Aqua Sciences machine, 215

AquaEst International, 215

aquifers, 2, 11-13, 40

Archimedes screw pumps, 136

Arizona Department of Administration(ADOA), 195, 198-199

Arizona Department of EnvironmentalQuality (ADEQ), 195-199

Arizona, University of, 53

ASHRAE standards, 152

Association of Universities for Researchin Astronomy, Inc., 157

Atlantis pump basin, 119

Atlantis rainwater storage tank, 119

Atlantis tanks, 119

Australian Slimline tank, 95

BBacillus thuringienis-israelensis (Bt-i)

Mosquito Dunk disk, 29

bio-retention gardens, 152

bioswales, 139, 214see also swales

Black Walnut Creek (MD), 162

black water, 3, 202, 204, 214

Blue Mountain Mesh, 22, 66

blue water, 2, 4

Brand, Cabell (VA), 121

Business Week/Architectural RecordAward, 164

butterfly roof, 65, 80, 132, 174-175

CCamino Blanca Residence (Santa Fe,

MN), 109

Camp Aldersgate Commons Building(AK), 216

carbon credits, 214

Carkeek Park Environmental LearningCenter (WA), 160-161rainwater catchment system in, 161

carwash reclaim pit, 85

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see also vehicle washing, reclaim pit

Casa Rufina (Santa Fe), 114

catchment area for rainwater, see rain-water catchment areas

CDP King County III, 171

Chapman Companies, 109, 112

Chesapeake Bay, 162

Chesapeake Bay Center, 164

Chesapeake Bay Foundation

Philip Merrill Environmental Center,162

chlorination process, 43-44, 145, 159

Chultuns, 7

cistern systems, 7, 31, 87, 120, 128, 131

cisterns, above-ground, 18, 26, 28, 40,44, 46, 80, 86, 107-108, 121, 153,163, 194, 203

cisterns, below-grade, 6-7, 15, 26, 28, 40,72, 80, 116-117, 127, 150, 214

cisterns, capacity of, 33, 38-39, 41

cisterns, corregated metal, 8, 11, 84-85,114, 145, 176

cisterns, maintenance of, 37, 77, 88

cisterns, nutrient levels in, 22

cisterns, as storage systems, 12, 23, 25-28, 32, 73, 79, 112-113, 131, 137,147, 149, 171, 179, 193

cisterns, and water quality, 29, 82, 88

cloud seeding, 12

Club Casitas de Las Campanas (SantaFe, NM), 120

Cole residence (San Juan Islands), 106

concrete unit pavers, 62-63see also permeable pavements

Condensate Recovery Projects, 183

conveyance systems, see rainwater con-veyance systems

cooling tower bleed-off water, xvi, 2

cooling tower blow-down water, 178,193, 195

collection of, 99, 181, 195, 199

Cryptosporidium, 30

DDarco tanks, 109, 114, 120-121

Department of EnvironmentalResources (MD), 49

Department of Natural Resources

(WA), 171

Dipstik, 82

distribution system for rainwater, seerainwater distribution

Dorrance H. Hamilton Building andPlaza (PA), 214

downspouts, 65-68, 72, 75, 95, 101-102,112, 138, 154-155, 165-166

filters for, 69, 71

drinker boxes, 205-209

drinking water, xiii, 7, 36, 42, 86, 88, 168

drip irrigation systems, 13, 29, 32, 132,142, 176see also landscape drip-irrigation

DRS Switching System, 115, 120-121

drywells, 54

EEarth Rangers Center (Woodbridge,

CA), 127

Eco Building (Phoenix, AZ), 87

Egan, Betty, 118, 120

Eggleston Services (VA), 122-123

El Monte Sagrado Living Resort andSpa (NM), 124

Emerging Technology Grant, 156

Energy Star Award, 173

Energy Star rating, 149

Environmental Building News, 215

Environmentally Responsible DesignProjects in the Nation, 149

FFamilian Northwest H2O FloPro moni-

toring system, 137

Feather and Fur Animal Hospital(Austin, TX), 2

Ferguson, Bruce K., xii

filtration, see rainwater filtration

fire protection, using rainwater, 128

First Green Post Office, 167

first-flush devices, xv, 7, 14-15, 18, 21-25, 32, 47, 69, 72-76, 78, 87, 95,107, 117, 157

flocculation tank, 159

flooding, see urban flooding

fog collection, xiv, 4, 99, 199-201

Fog Project (Nepal), 201

230 | Design for Water

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FogQuest water tank, 201

Ford, Henry, 134

Ford Motor CompanyRouge Factory, 134Visitor Center, 135-136

Fort Worth Botanical Gardens, 35

Franklin, Benjamin, 99, 131

French drains, 48, 54, 58, 63

freshwater, xiii, 2- 4

freshwater footprint, 2

GGeorgia, University of

School of Environmental Design, xii

Giaradia, 30

Gould (G&L) pump, 139

Graf Universal filter system, 115, 120-121

grains of moisture, 189-190, 192see also condensate

Grand Prairie Animal Shelter, 128, 130

Grand Prairie, City of (TX), 128

green roof, 134-135, 172, 177, 214

Green Streets Project, 49-53

green water, 2, 4, 13, 48

greywater, xvi, 2, 99, 111, 204

reuse of, 4, 203, 214

greywater systems, 100, 110, 112, 202-203

groundwater, 2, 12-13, 171

Grundfos pump, 95

Grundfos SQE Submersible System, 121

Guelph, University of, 213

gutters, 65-66, 68-71, 79, 148, 165

as catchment areas, 86, 95, 133

guzzlers, 205-210

HHarvesting Rainwater for Wildlife, 206

Hawaii Volcanoes National Park, 142

Hayward Power-Flo II, 111

HEB store (Austin, TX), 3

Heritage Middle School (NC), 149

Hilo Board of Trade, 143

hydrologic cycle, 11, 48, 212, 215

Hydromatic HE-20 Submersible system,115, 120

Hydros Group, 115, 120-121

IInnovative Artist-Made Building Ports

Registry, 171

intensity of use (of rainwater harvestingsystem), 34, 36

International Rainwater CatchmentSystems Association, xi

irrigation, 1, 3, 7, 12, 52, 58, 62, 128,150, 162see also landscape irrigation

irrigation systems, 25, 112, 131, 133,156, 195gravity feed, 114

Island Wood School (Seattle, WA), 3

JJ.J. Pickle Elementary School, 147

Jack Nicklaus Signature golf courses, 120

Jade Mountain, Inc. (Boulder, CO), 110

KKaibab Guzzler, 206

Kearney residence (Tucson, AZ), 107

Kilauea Military Camp (KMC) (HI),142, 143

King County Department ofTransportation (WA), 171

King Street Center, 171, 173

Kitt Peak National Observatory(KPNO), 142, 157

LL.F. Manufacturing, Inc., 131

Lady Bird Johnson Wildflower Center(Austin, TX), 131, 133

Landscape Architecture magazine, 103

landscape drip-irrigation, 176see also drip-irrigation systems,landscape irrigation

landscape irrigation, xvi, 2, 7, 24-25, 27,30, 32, 39-40, 72, 112, 114, 126,139, 142, 147, 162, 168, 171, 181,183, 193, 199, 202-203, 214

landscape retention basin, 48, 50

landscape swales, 13, 33, 47see also swales

Langston-Brown Community Center,151

Langston High School (VA), 151

Latent Cooling Load, 185

Index | 231

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Leadership in Energy andEnvironmental Design (LEED), 4

Leaf Beater Rain Head, 25, 69, 72

Leaf Eater Rain Head, 25, 69, 72

leaf filter baskets, 95

Leafslide box, 25

LEED Certification, 4, 126, 136, 139,150-152, 156, 162, 164, 169, 176, 213

Legionnaires’ disease, 193

Level Devil, 84

Levetator, 82

Liquidator, 82

Little House Cistern, 132

Living Beyond Our Means: NaturalAssets and Human Well-Being, 1

Living Machine bioreactor, 126

Lloyd Crossing, 214-215

Low Impact Development (LID), 49

Low Impact Development Center, 49

Low Impact Development DesignStrategies: An Integrated DesignApproach, 49

Lowe’s Home Improvement Center, 35

MMcClary, Michael, 1

McKinney Independent School District(ISD), 147

McKinney Public Elementary school,128

microbasins, 48, 52-53, 56, 61, 63

Millennium Ecosystem Assessment(MEA), 1

Mohave County AdministrationBuilding (MCAB), 195, 198-199

Moseley Architects, 193

mosquito breeding, 19-20, 22, 25, 27,77, 85, 151

mosquito dunks, 29, 77-78

Muir, John, 65

municipal water supply, xiii-xiv, 7, 13,27, 29, 31, 37, 40, 95, 122-123, 139,156, 171, 204, 211see also alternate water supply

NNational Optical Astronomy

Observatories (NOAO), 157, 159

National Sanitation Foundation (NSF),14, 30-31

National Science Foundation (NSF), 157

Natural Resources Defense Council(NRDC), 203-204

Neuse River, 151

New Braunfels Utilities, 83

nonpotable water, see water, nonpotable

North Carolina Legislative Building, 180condensate collection in, 178

OOPUS Corporation, 195

Oregon Convention Center, 100-101

Orical’s air-conditioning condensaterecovery system, 182

ozone, for water treatment, 87-88see also water treatment systems

PPartnership for Advancing Technologies

in Housing (PATH), 109

passive rainwater harvesting, see rain-water harvesting systems

percolation, see rainwater percolation

permeable pavements, 48-49, 52-54, 58-59, 63, 127, 136, 152, 213-214

Philip Merrill Environmental Center, 162

photovoltaic solar panels, 126, 151, 160

Pima Community College (AZ), 5

Pioneer Galaxy water storage tank, 94-95, 99

Piper’s Creek watershed (Seattle), 103

pollutants in rainwater, xi, xv, 15, 18,20-22, 42, 50-51, 87, 100, 103, 105-106, 166, 181, 202, 213

Portland, City of, 49, 156

Environmental Services, 50

Office of SustainabilityDevelopment, 156

Portland State University, 153

Portland Vehicle Distribution Center

Toyota Motor Company, 136

potable water, see water, potable

potholes, 205

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Prairie Paws Adoption Center (PPAC)(TX), 128

psychrometer, 187-188

psychrometry, 183

purification, of rainwater, see rainwaterpurification

RRain Alert, 84

rain cups, 80-82

rain gardens, 48, 54, 61-63, 100-102,104-105

Rain Harvesting Pty Ltd., 72, 84, 206

rainbarn, 14-15, 19

rainbarrels, 77-78, 81, 161-162

rainchain spash pad, 20

rainchains, 18, 20, 77-82

Raincoat 2000, 14

rainhead, 25

RainPC, 88, 92

Rainstore3 water harvesting structure,154

rainwater, captured, 52, 114, 128, 140,150, 173, 179

rainwater catchment areas, xv, 15, 18,23, 36-40, 47, 87contaminates in, 24, 159concrete, 206-207

rainwater catchment systems, 6, 11, 13,19, 65, 72, 100, 115, 117, 120-122,145, 171, 211-212, 216for laundry use, 178for potable uses, 106, 109

rainwater collection, xi-xvi, 4, 7, 11-12,18, 37, 41, 47-48, 54, 63, 68, 82, 86,96, 126, 128, 131, 133, 137, 139,159, 169, 174, 176, 195

rainwater collection systems, 7, 110,131, 150-151, 156, 164, 176, 178,203

rainwater, conservation of, 96

rainwater, contaminants in, 75, 92

rainwater conveyance systems, 13-15,18-19, 25

rainwater distribution, 3, 13-15, 27, 29,179

rainwater endowment, 15

rainwater filtration, xiv, 13, 15, 24-25,30-31, 126, 145, 149, 154

rainwater harvesting systems, 6-7, 11-13, 18, 20, 22, 26, 36, 63, 112, 122,127, 133, 139, 147, 149, 157, 159,168, 174commercial, 16, 121cost of, 94design of, 33industrial, 134municipal, 164for nonpotable use, 14, 32, 72, 77,

153passive, xii, 3, 5, 33-34, 36, 48-50,

52-60, 62-63, 175for potable use, 14-15, 23, 32, 96,

137, 150potential of, xv, 15residential, 17, 96, 106, 115return on, 124, 169for wildlife, 205

rainwater percolation, 13, 32, 48

rainwater purification, 13-15, 18, 23, 30,44, 87, 92, 126

rainwater runoff, 13, 22, 176see also rooftop rainwater

rainwater storage system, xiii, 12-14, 22,24, 27, 29-30, 35-36, 50, 47-48, 52,54, 69, 87, 92, 139, 150, 167, 174

Rancho Encantado (NM), 118, 120

Rancho San Marcos, 109-110

Rancho Viejo (Santa Fe, NM), 115-116

reclaim pit, 85

reclaim water, 3, 173

Reunion Building, 4

reverse osmosis, 86

Roanoke Regional jail (VA), 176

roof washers, xvi, 14-15, 20, 22-24, 69,72, 75-76, 87, 95, 121, 161

roofs, copper, 67

roofs, corrugated, 66

roofs, demossing of, 68

roofs, see also butterfly roof

rooftop catchment, xv, 12, 14, 18, 99

rooftop catchment areas, 38-39

rooftop gutter collection system, 133

rooftop rainwater, 52, 109-111, 162, 214catchment systems, commercial, 99collection of, 23, 152, 161harvesting of, 18-19, 22, 25, 128, 136runoff, 11-12, 32, 37-39, 42, 50, 63,

109, 114, 164, 178, 212, 214

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Rouge River, 134

Roy Lee Walker Elementary School(TX), 147

SSafeRain Vertical Diversion Valve, 24, 73

salt water intrusion, 13, 106

San Antonio Water System, 182

San Juan Fire Station No. 1 (WA), 164

San Juan Islands, 105

SAWS Conservation programs, 183

Schrickel, Rollins and Associates, Inc.,128

Seattle, City of, 103, 105

Seattle City Hall, 169

Seattle Civic Center, 169

Seattle Public Utilities Natural DrainageSystem, 103, 106, 213

SEDI building, 149

Sidwell Friends Middle School (WashDC), 213

siphonic roof drainage system, 178

snow, collection of, 41-42

soak-a-ways, 54

soil erosion, xi, 13, 32, 48, 51, 63, 101

solar hot water system, 42

solar water distillation systems, 32-33

splash boxes, 154-155

splash pads, 20, 79-80, 155

St. Michael Parish Day School StudentCenter (Tucson, AZ), 145

Stay-n-Play Pet Ranch, 93

Stephen Epler Residence Hall (OR),153-154

storage system, see rainwater storagesystem

stormwater, 2, 12, 21, 23

stormwater basins, 53, 57

stormwater catchment, xvi, 4, 13-14, 47,177, 212, 216

stormwater collection, xi, xiv, 54, 63, 72,126, 195, 211, 214

stormwater first-flush, 78-79

stormwater gardens, 100

Stormwater Infiltration, Introduction toStormwater, and Porous Pavements,xii

stormwater management, 47, 49-50, 52,103, 122, 134, 136, 152, 154, 161

stormwater runoff, 5, 12-13, 41, 54, 56,142, 151-153, 171, 177, 214

SunCor, 115

supplemental water supply, 27, 36-40

sustainable building program, 169

Sustainable Site Development,Stormwater Practices for New,Redevelopment, and Infill Projects, 50

swales, 48, 53-55, 57-58, 61, 63, 101,105, 108, 128, 213see also bioswales

TT.C.Williams High School (VA), 193, 195

Texas Guide to Rainwater Harvesting, 96

Texas State Energy Conservation Office,147

Thomas, Terry, 22

Tidal Wetland Living Machine, 126

TimberTank, 35, 82

tinajas, 205

Tohono O’odham Nation, 157

toilet flushing, xiii, xvi, 24, 72, 95, 139,142, 150, 156, 161-162, 168, 171,176, 195, 202, 214

Toto hand-washing cascade toilet, 202

Tower Cistern, 132

Toyota Motor Sales, 139

Global Earth Charter, 136

Triangle J Council of Government’sHigh Performance Guidelines, 150

trick tanks, 205-206

Tucson Barrio Redevelopment Area, 112

Uumbrellas, upside-down, 213

Uniform Plumbing Code, 19

United Nations Millennium EcosystemAssessment, 215

U.S. Department of Agriculture, 174,176

U.S. Department of Housing and UrbanDevelopment (HUD), 110

U.S. Environmental Protection Agency,149, 173, 215

U.S. Green Building Council (USGBC),xi, 4, 136, 139, 151, 156, 162, 164,

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176, 213

Using Graywater in Your HomeLandscape, 203

U.S. Postal Service, 166-167

Environmental Policy and GuidingPrinciples, 166

urban flooding, xi, 13, 48, 103, 212

Vvehicle washing, 137, 159, 211-212

Vertical Corrugated metal pipe (CMP), 85

WWarner, William, 206

Warwick, University of (England)

School of Engineering, 22

wastewater, 128, 181, 183, 202

water balance analysis, 36

water budget, 33, 36-41, 88

water budget worksheet, 88, 90-91

water catchment systems, xi, 213costs of installing, 212for wildlife, 205-206

Water Cistern Construction for SmallHouses, 46

water collection system, 37, 181

water conservation, 115, 182

water, distilled, 192

water footprint, 2, 4

Water Harvesting Machine, 215

water, nonpotable, xvi, 4, 14-15, 28, 30,36, 173, 211

water, potable, 4, 14-15, 18, 24, 28, 33,36, 128, 157, 169, 174, 215

water purification systems, 32

water runoff worksheet, 88-89

water treatment systems, 12, 30, 86-88,94, 128, 179, 181, 193

WaterPyramid, 215-216

watersheds, 47-48

Wilcut, Eddie, 182

Wilkes County Log Home Development(NC), 117

Willamette River, 50, 100, 139

Willborn Bros. Co., 206

WISY filter, 23, 86

Wollongong Botanic Garden (AUS), 94

World Birding Center, xiii-xv

Wright Rumstad & Company, 171

XXero Flor system, 134

ZZENON membrane bioreactor, 128

Index | 235

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Page 256: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

HEATHER KINKADE-LEVARIO’Spassion for rainwater har-

vesting began as a way to createa sustainable component forcommercial developments thatwere lacking in any such ele-ments. She has worked withwater collection through herLand Use Planning andLandscape Architectural profes-sion with ARCADIS, as a studentworking on her Ph.D. in UrbanGeography and Sustainability,and as the 2005-2007 Presidentof the American RainwaterCatchment Systems Association(ARCSA), and has publishedmultiple rainwater collectiondetails in McGraw Hill’s 2002Time-Saver Standards for UrbanDesign and in Wiley’s 2006Time-Saver Standards forLandscape Architecture. Her

writing has appeared in LandscapeArchitecture Magazine, and she isthe author of a previous book,Forgotten Rain RediscoveringRainwater Harvesting, whichwon both a state award and anational award in communica-tion from the American Societyof Landscape Architects.

About the Author | 237

About the Author

Page 257: Design for Water Rainwater Harvesting, Stormwater Catchment, And Alternate Water Reuse

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