rainwater harvesting 101 - grow new york city

8/9/2019 Rainwater Harvesting 101 - Grow New York City

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Rainwater Harvestin 101


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RAINWATER HARVESTING 101

COUNCIL ON THE ENVIRONMENT OF NEW YORK CITY

Robert J. Kafin, Esq., Chairman

Marcel Van Ooyen, Executive Director

Prepared by:Julia Leung, DEC Summer InternforCouncil on the Environment of New York City51 Chambers Street, Room 228New York, NY 10007(212) 788-7900

August 2008


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PREFACE

The Council on the Environment of NYC (CENYC) is a hands-on non-profit that has been improving NewYork City's environment for over thirty years. CENYCs dedicated staff green our neighborhoods, create theenvironmental leaders of the future, promote waste prevention and recycling, and run the largest farmersmarket program in the country. CENYC achieves its mission through the following projects and programs:The Open Space Greening Program, Greenmarket, The New Farmer Development Project, EnvironmentalEducation Training Student Organizers, Learn It, Grow It, Eat It and Office of Recycling Outreach andEducation.

The Open Space Greening Program (OSG) empowers people in neighborhoods throughout the city tocreate, manage and sustain community gardens and park/playgrounds. OSG provides best practicesworkshops, services, tools, donated plant material, and open space planning/mapping information andother services. Grow Truck provides tools, donated supplies, plants and horticultural advice and assistanceto gardening groups all over New York City. The Plant-A-Lot Project gives substantial material and

technical assistance to several new gardens each year and helps the 45 existing gardens created in prioryears.

Since 2002, OSG staff has taken the lead in building and maintaining rainwater harvesting systems incommunity gardens across the five boroughs, leading educational workshops, assisting communitygardeners in identifying alternate water resources and building low cost systems. CENYC is an activemember of the Water Resources Group, a network of NYC greening and environmental organizationspromoting sustainable water conservation practices in NYC. The New York State Department ofEnvironmental Conservation (DEC) recognized CENYCs efforts with The Environmental Excellence Awardin 2006. This manual was created to disseminate to a wide audience the design parameters and buildingtechniques used by CENYC staff.

Summer intern was able to prepare this document thanks to a grant from The New York State Departmentof Environmental Conservation in 2008 for Pollution Prevention. Ms. Leung provided many of the photos,charts, and drawings used. OSG staff, Lars Chellberg, and Lenny Librizzi provided invaluable guidance,advice, and editing of the manual. CENYC Executive Director Marcel Van Ooyen and Assistant ExecutiveDirector Julie Walsh edited the text. Additional information and assistance was provided by NYCcommunity gardeners and members of the Water Resources Group.


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TableofContentsIntroductionofRainWaterHarvesting 2

Historyof

Rain

Water

Harvesting

5

BenefitsofRainWaterHarvestinginUrbanAreas 6

CurrentEfforts 7

Materials 10

Wheretoobtainsupplies 11

CostEstimates 12

PVCApplications 14

Sizingofthetankandroofwasher 18

Construction 21

Tank

23

Leaders 26

RoofWasher 30

Overflow 33

Anchoring 36

DripIrrigation 39

FiltrationSystems 41

Treatment 42

Aesthetics 43

RoofingMaterial

45

SeasonalMaintenance 46

LivingwiththeRWHsystem 47

ExistingRWHSystems 48

10WaystoConserveWater 49

Bibliography 50

FeedbackForm 51


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1

Introduction"Itisn'teasytocomeupwith'onesizefitsall'instructionsforbuildingrainwaterharvesting

systemsbecause

of

variations

in

styles

of

roofs,

downspouts,

storage

tanks,

and

garden

layouts.

Youhavetouseacombinationofresearch,commonsense,ingenuity,anddumblucktodesign

andbuildyoursystem."

LennyLibrizzi,AssistantDirectorofOpenSpaceGreeningattheCENYC

Rainwaterharvesting(RWH)isthemeansofcollectingandstoringrainwaterinlarge,durable

containers,usually,collectingfromrooftopgutters.RWHsystemscomeinavarietyofshapes

andsizes(seepicturesbelow).


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2

Rainwaterharvestingsystemsarefairlyeasytoconstruct.TanksinNYCcommunitygardens

rangeinsizefrom300to1000gallonsbutcanbeassmallas55gallonsandasbigas10,000

gallons.Rainwatercollectedfromthedownspoutofanadjacentbuildingorshedinthegarden

isredirectedtothewaterstorageareainthegarden.TheRWHsystemincludes3parts(see

drawing):thetank(1),thefirstflush(2)andtheoverflowpipe(3).

Duringarainfalleventwaterfromthegutter flows intothedownspout. Insteadofthewater

goingintothesewersystem,therainwaterharvestingsystemdivertsthewaterintopipes.This

diverterconsistsofa3wayteewithaplungerinplaceduringthesummer.Thisplungerkeeps

thewaterfromenteringthedownspoutandforces ittoflow intotheharvestingsystem. It is

takenoutinthewinterwhenrainwaterisnolongercollected(4).


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3

Hereisacloserviewofhowtheplungerworks.

Thepipesleadtoaroofwashersystemwhichisacontainmentareaforthefirstfewgallonsof

water.Sincetheinitialflushesofwatercontainrooftopdebrisandleaves,theroofwasheracts

asafilteringsystembyseparatingthedirtywaterfromthecleanerwater.Oncetheroofwasher

isfull,thecleanerwaterenterstheraintank.Assoonasthetankisfull,excesswaterflowsinto

the overflow pipewhich leads to an adjacent rain garden (5), is directed back towhere itoriginallyflowedorpipedunderground.Araingardenisaplotcontaininghardyplantsthatcan

survivewithbothsaturatedanddrysoil.


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4

Historyofrainwaterharvesting

Rainwaterharvestingisanancientpractice.Manydifferentcultureshaveusedthistechnology

foragriculturalpurposes.ThePhilippineshavebeenusingrainwaterforriceterracesfor

thousandsof

years

now.

Indian

history

indicates

that

rain

water

systems

have

been

in

use

since

3000BC. Usagecanalsobetracedback2000yearsagoinThailandandotherpartsof

SoutheastAsia,wheresimplegutterswereusedtofilljarsandpots.Theearthdamsofancient

Egyptwereusedtocontrolrunoff.Ancientrainwatercisternscanstillbeseenontheislandsof

CapriandMalta.

Inadditiontorainwaterharvesting,theRomansalsousedtheirsystemsasairconditioners.

Whenthewaterevaporated,itcreatedacoolingeffectinthemicroclimate.Astheir

populationsstartedtoincrease,theRomansdevelopedundergroundcisterns.Thisway,less

waterwouldbelostduetoevaporation.Theyconnectedthesecisternstoabovegroundpools

asameansofwaterfiltration.Whenthesepoolsoverflowed,thecleanerwaterwouldenter

thecisterns.

This

design

was

an

inspiration

for

modern

day

rain

barrels.

The

Romans

shallow

poolmirrorsthemoderndayroofwasherorfirstflushsystem.

TheworldslargestcisternistheYerebatanSarayi,builtbyCaesarJustinianin527AD.Itis

locatedinmoderndayTurkeyandisapopulartouristattraction.Itis140metersby70meters

bigandcanstoreupto80,000metersofwater.Thishugestructureiscompletelyunderground

andinvolvesaseriesofintersectingvaults.BinbirdikisanothercisterninIstanbul,createdby

CaesarConstantinein389ADthatcanstore80,000meters.Howeverconstructionofthese

cisternsstoppedduetothedifficultyofbuildingundergroundandtheoutbreakofhumanfecal

contaminationinlargecities.1

Inthe

1970s,

anew

technology

of

rain

water

harvesting

was

developed

where

storm

water

wasstoredinwellstoragetanksintheformofdifferentsizedponds.Athinlayerofredclay

wasusedtolinethebottomofthepondtopreventseepageandtreeswereplantedaroundthe

pondtopreventexcessiveevaporation.Over40,000ofthesesystemswerebuiltintheLoess

PlateausofChina.2

Althoughrainwaterharvestingwasasignificantandsuccessfuldesigninthepast,itspopularity

hasdeclinedoverthecenturies.Urbanizationdemandedamorecentralizedwatersupply

system.Watershedsandpipelinescameintouseandrunningwaterbecameoneoftheworlds

greatestinventions.However,duetomoderndaywaterpollutionanddrought,rainwater

harvestingtechniqueshavecomebackintopracticeagain.


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Benefitsofrainwaterharvestinginurbanareas

Bykeepingstormwateroutofthesewagesystem,gardenershelpkeeptheirlocalwaterbodies

clean.BecausemostofNYCispavedover,rainwatercantbeabsorbedbytheground.Instead,

itruns

across

the

pavement,

picking

up

oil,

street

debris,

animal

feces

and

other

waste

as

it

moves. Thisrunoffthenentersthesewersystem.

Unfortunately,notallrunoffmakesittoatreatmentplantbeforeenteringthecitysriversand

harbor. ThisisbecausemostofNYCisonacombinedsewersystem,wherebythesamepipes

areusedtotransportbothstormwaterrunoffandhouseholdwastetosewagetreatment

plants.Ifthesetreatmentplantsoverflow,thecontaminatedwaterthenentersthewater

bodiessurroundingNYC.

Duringdryweatherthesewagetreatmentsystemgenerallyworkswell,butthesetreatment

plantscanonlyhandleabouttwicetheirdryweathervolume.Thismeansthatheavyrainsoften

resultin

combined

sewer

overflows

(CSOs),

which

release

untreated

wastewater,

storm

water

andstreetdebrisintolocalwaterways.Untreatedsewagecancarrydiseasecausingpathogens

andnutrientrichorganicmaterial,whichcanchoketheHarborsecosystem.

Notonlycanrainwaterharvestingpreventwaterpollution,italsoconserveswater.Typical

systemscanstoreupto1000gallonsofwater.Harvestingduringrainydaysinspringand

summerprovidesasourceofwaterforthedryspellsbetweenrainevents.Insteadofrunning

thehosetowateryourgarden,youcanusetherainwaterstoredinyourtank.Thiswillrelieve

thestrainonourreservoirsandalsosaveyoumoneyonyourwaterbill.Fortypercentof

householdwaterconsumptionisusedondomesticirrigation!3

Rainwaterharvesting

has

proven

to

be

successful.

The

35

rain

water

harvesting

systems

workinginNYCscommunitygardenscollect422,900gallonsofwatereveryyear.Thatsenough

for264,313toiletflushes!

Ofcoursesmallscaleconstructionofrainwatersystemsisnotenoughtosignificantlyimpact

ourenvironment.However,ifrainbarrelswereusedmoreextensivelyandraingardensbecame

alargerpartofcitylandscapeplanning,waterconservationwouldhaveagreater

environmentalimpact.Wewouldexperiencecleanerwaterbodies,lessfloodingandlower

watercosts.

Rainwaterharvestinghasgreatpotentialtoreducerainwaterflowintostormdrainsby

collectingrainwater

in

gardens

and

can

reduce

the

dependence

on

the

NYC

watershed.

Every

dropofwatercountsandconservationisthemostsustainable,costeffectivesourceofwater

supplyforourregion.


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Currentefforts

CommunitygardenersacrossNorthAmericaandaroundtheworldhaverevivedthepracticeof

usingrainbarrelsintheirgardensoutofnecessity.

InSeattle,budgetconstraintsandrisingwaterpricesspawnedtheconstructionofrainwater

harvestingsystems.SomeofSeattlesrainwaterharvestingsystemsareworksofart.Heregate

pillarssupporttheflowofrainwaterfromthebuildingontherightintothecisternontheleft.

SeattlePublicUtilitieshaverecommendedchangestothelanduseandbuildingcodesthat

encouragewaterconservation.SPUhasalsosponsoredsomewildlysuccessfulsalesofrain

barrelstoSeattleresidents.

The10,000RainGardensPrograminKansas

Cityisanexampleofregionaleffortsto

educateandintroducewaterconservationto

theKansasCitycommunity. Raingardensare

areasofvegetationonporousgroundthatcan

filter

and

drain

excess

storm

water.

Kansas

Cityofficialsencouragetheirresidentstoplant

thesegardensontheirownproperty.

Thespecial

curves

on

this

gate

represent

the

monthly

rainfallinSeattleandtheamountofwatercollected

yearround.

Theoverflow

pipe

of

this

Seattle

cistern

creates

amini

waterfall.

AcatenjoyingtheraingardeninKansasCity.


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TheCityofVancouverdesignsandmanufacturesrainbarrelsforresidentstousefor

irrigation(seepictureonright).Vancouversubsidizesthecostoftherainbarrelsby

50%.Over2000barrelshavealreadybeensold.

Portland,Oregon,grantedapermitforahouseholdtoharvestrainwaterfor

useindoorsduringallbutthedrysummermonths(seesketchandpicture

below).ThewaterundergoesenoughfilteringtomeetEPAsstandardsfor

drinkingwater.In1998thissystemcostlessthan$1,500toinstall.


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Maplewood,Minnesotahasforgedacoalition

betweenitswaterandsanitationdepartments

andresidentiallandownerstoplantlargescale

curbsideraingardensthatreducestormwater

sewage(seepictureonleft).

TheMinnesotaArboretumusesitsparkinglotsto

demonstratebestlandscapepracticessuchas

plantingraingardensandusingpermeablepavers

toreducecontaminationcausedbystormwater

runoff(seepictureonright).

TheCityofTorontoDownspoutDisconnection

Program

offers

a

free

service

to

homeowners

to

disconnectdownspoutsfromthesewersystemand

installrainbarrelswhichareavailableatadiscount.

Chicagoalsoencouragesitscitizenstodisconnect

downspouts.Inaddition,ChicagosWaterAgenda2003includedarooftopgardeninitiative,a

pilotprogramforpermeablealleys,andraingardensplantedintheCitysrightsofway.

Austinoffersrebatesofupto$30fornewlyinstalledrainbarrelsandofupto$500for

installationofrainwaterharvestingsystems,followingdesignapprovalbytheCity.

In2001,

the

first

Drought

Emergency

to

be

announced

since

1989

was

declared

in

New

York

City.Thereservoirlevelswere40%belownormalwhichresultedinmandatorywateruse

restrictions.TheWaterResourcesGroup(WRG)wasfoundedasaresponsetothissingle

droughtyear.SincethenWRGandCENYChavebuilt35rainwaterharvestingsystemsinNew

YorkCity,collectingover422,900gallonsofstormwaterperyear.

NewYorkCitycurrentlylagsbehindothercitieslikeBostonandChicago,whichcapture90%of

theircombinedsewageoverflow;NewYorkCityonlycapturesabout70%,accordingtothe

city4


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9

Materials

Everyrainwaterharvestingsystemisdifferentbut

theydohavesimilarities.Hereisacomprehensivelist

oftools

and

supplies.

Your

system

will

use

many

of

thesebutmaynotrequireallofthem.

Tools:

Drill Holesawattachmentorjigsaw Screwdrivers Hammer Level PVCsaw(seetopsawinpicture)andmetalhacksaw(bottomsaw) Tinsnipsorsheetmetalshears Crimpingtool(seepictureonright)andcablecuttingtools

Gutters:

Gutterlengths Leadersandbends Prefabricatedgutterhangers Plumbingstrap(forsecuringpipestowall) Flexible,accordionstyleexpandableplasticpipe Tubeofguttersealantandcaulkguntoapplyit PVCcleanerandcement Teflontape(forcreatingawatertightsealonthreadedbushings)

Barrelstoragesystem:

TanksandPVCpartsorothermaterialstoconstructthemanifold.Herewehavea

capped4waytee(seeleftmostpicture)

anda90and45elbowrespectively(see

rightmostpicture)

Windowscreenorscreenedventsformosquitoproofvent

Bulk

head

fittings

(An

elongated

compression

fitting,

which

will

allow

pipe,

to

run

throughabulkhead)

Platformmaterialsuchastreatedlumber,plasticlumberorconcreteblocks Eyebolts(forsecuringtank) Spigot Metalflangesofcorrespondingsizetospigotandhardware Ropeorcablingsuppliestosecurethetank


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Wheretoobtainsupplies

Polyethylenetanksarebestpurchasedlocallybecauseofhighshippingcosts.Searchonlineforlocalsuppliers.Youcanpersonallyshipsmallertanksandsaveonextraexpenses.Hereare

somewebsites

that

sell

tanks:

http://www.liquidlogictanks.com/index.html http://www.tankdepot.com/ http://www.rainbarrelsource.com/ http://www.rainbarrelsandmore.com/ http://www.aquabarrel.com/

Dripirrigationsuppliersinclude: http://www.dripdepot.com/ http://www.dripirrigation.com/ http://www.rainbird.com/drip/index.htm http://www.dripworksusa.com/ http://www.netafim.com/ http://www.chapindrip.com/ http://www.farmtek.com

Downspoutfiltersandavarietyofotherspecializedpartsforsystemscanbepurchasedfrom: http://www.starkenvironmental.com/a1filtration.html http://www.braewater.com/ http://www.rainharvesting.com.au/default.asp http://downspoutfilter.com/index.php http://rainharvest.com/shop/default.asp

ToolsandPVCgutterpiecescanbepurchasedatyourlocalhardwarestores.LowesorHomeDepotalsosellstheseitems.Forlocationsnearyou,visittheirwebsitesat

http://www.lowes.com/orhttp://www.homedepot.com.


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CostEstimates

Notethatthepriceslistedindicatethevaluesin2008.Adjustfora15%20%annualincrease.

Polyethylenetanks:

Generally,

tanks

cost

$1

per

gallon

but

it

can

sometimes

be

too

big

to

transportonyourown.Shippingcostsareaboutanadditional$1pergallon.

LeadersandGutters:Thenumberofleadersandguttersneededpersitewillvarydependingontheroofconfiguration.A10footlonggutteris$15.00,a10footlong2x3leaderis$9.00,and

a10footlong3x4leaderis$16.00.Connectingparts,cornersandbendsareanywherefrom

$2.00to$10.00.

Platforms:Platformsforcontainerscanbemadeoutofcinderblocks,plywoodoranyother

sturdymaterial.Whilethetankislightwhenitisempty,rememberthatafulltankofwatercan

weighthousandsofpounds.Asmall55gallontankweighsover400poundswhenfull!Besure

thatyourplatformisstrongenoughtowithstandlargeweights.Cementblockscanbe

scavengedfromconstructionsites.Shouldyouhavetopurchasethem,8x16cementblocks

are$1.50each.Thelumberpricesare$16.00forapressuretreated8footlong2x10piece

or$13.00forapineorfir8footlong2x10piece. An8footlong4x4piececosts$12.00.

4x4lumberlaidlengthwiseinalternatingdirectionsplacedonagravelbasemakesasturdy

platform(seepictureonpage25).Usingpouredconcretepilingsandabuiltwoodendeckfora

platformmaycostabout$500.

MiscellaneousHardwareandspecializedparts:Thiscategoryincludesaccordionconnectorpieces,screens,sealants,sheetmetal,screws,nuts,bolts,gravel,filteringpartsandsupplies,

roofwashers,weedfabricandotherspecializedparts.Thesepartswillvarybysiteandtypeof

barrel.

PlumbingSupplies:Theamountofplumbingyouneedvariesdependingonthesystemyouaremaking. Thiscategoryincludesoverflowpieces,PVCpipes,connectorpieces,rubberfittings,

spigots,bulkheadfittingsandthepipingneededtodrawthewaterawayfromthesystem.

Upgradeswillincludesoakerhosesorothertypeofoverflowdisperserandroofwashers.A

sophisticateddripirrigationsystemcouldadd$5001000tothecost.

ToolKit:Somespecialtytoolsareneededsuchasdrillbits,screwbits,hacksawblades,tinsnips,holesaws,caulkgun,caulkingorsilicon,jigsaw,pliersandtapemeasures.


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Costanalysisfora300gallonrainwatersystemin2008

Tank $300

ShippingofTank $300

LeadersandGutters $100

Platform

$300

Hardware $100

Plumbing $100

ToolKit $50

TotalCost $1250

Costanalysisfora1000gallonrainwatersystemin2008Tank $1000

ShippingofTank $1000

Leadersand

Gutters

$200

Platform $600

Hardware $200

Plumbing $200

ToolKit $50

TotalCost $3250

Ifthereisnotalreadyanexistingrooforshednearby,ashade

structurecan

be

constructed.

One

possible

design

is

the

winged

structureseenhere:

Costanalysisfora300gallonrainwatersystemwithwingedstructurein2008Tank $300

ShippingofTank $300

LeadersandGutters $100

Platform

$300Hardware $100

Plumbing $100

ToolKit $50

MaterialsforShadeStructure $2500

TotalCost $3750


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PVCApplicationsUptonowPVCorpolyvinylchloridehasbeenthekeypipingmaterialintherainwater

harvestingsystemsinNYCcommunitygardens.Thishardplasticisinexpensive,durable,easyto

useand

readily

available.

Tees,

elbows,

bushings

and

couplings

are

all

made

out

of

PVC.

AlthoughPVCisfairlystable,thereareenvironmentalhazardsinmanufacturingandburning

PVC.Wearecurrentlylookingforothersourcesthataremoreenvironmentallybenignbutalso

havingthesameflexibilitywithpartsasPVCdoes.Althoughmetalcanbeanalternative,itcan

becostly.IfthereisamaterialthatyouthinkcanbeareplacementforPVC,pleaseaddyour

informationorcommenttothiswiki:

http://www.waterresourcesgroup.org/wiki/index.php?title=Main_Page.

InordertojoinPVCpipestogether,usePVCspecificcleanerprimerandcement.PVCcleaner

primerremovesdirtandmeltsthesurfaceforultimateadhesion.Afterthepipeisclean,you

canusecementtojointhetwopiecestogether.Onlyapplycleanerandcementtotheoutside

partof

the

male

piece

(see

picture

on

left)

and

the

inside

part

of

the

female

piece

(see

picture

onright).Itisimportanttoholdthetwopiecestogetherfor20secondsafterapplyingthe

cementbecausetheymaymoveapart.After20seconds,thetwopiecesarepermanently

joined(seebottommostpicture).Wipeoffexcessglue.

Usebushingsandreducerfittingswhenitisnecessarytochangethesizeofyourpipes.These

comeinawidevarietyofglue(slip)andthreadeddesigns.


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This2x1slipbushingconnectsa2(diameter)pieceofpipe

witha1pipe.Slipbushingscanbeadheredusingthecleaner

andcementmethodmentionedabove.

This2x1slipandthreadbushingconnectsa2slippipewitha1threadedpipe.Thread

bushingscanbeadheredtightlyusingTeflontape.Rollthetapestartingattheendofthemale

threadbushingtowardsthemiddle.Twoorthreewrapsaresufficient.

PVCpartsareveryversatilesincenotworainwaterharvestingsystemsarealike.Many

differentcombinationsofPVCpartscanbeusedforthesamefunction.Hereare5different

waystoconnecta2pipewithapipe.

Itisveryimportanttoalignadjacentpipes.Thetwoteesinthefirstpicture(seepicturebelow)

mustalignexactlyinordertoconnecttothesamewall.Carelessglueingwillleadtoproblems.

Useahard,levelsurfacesuchasaconcretefloortohelpyoualignpipes.


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Thepipesinthesecondpicture(see

pictureonleft)mustbeexactly

perpendiculartoeachother.Theteeon

theleftwillconnecttothebarrel.Thetee

ontherightwillconnecttoexistingpipes.

Useamarkertoindicatethepointswhere

theonepipemustmeettheother.

Thepicturesabovealsopointouttheuseofpiping.Noticehowthetwoteesarejoinedineach

picture.Inthesecondpicture,thetwoteesarejoinedbyusingasmallpieceofpipeinbetween

them,calledasleeve.Theinteriorcouplingistooshorttobeseeninthispicture.Inasituation

whereyouwanttheteestobefurtherapart,suchasinthefirstpicture,justextendthesizeof

thepipetothedesiredlength.

Althougheveryrainwatersystemmustbecarefullyplannedbeforeactualconstructionbegins,

itisveryeasytomiscalculateormeasureincorrectly.Oftentimes,errorsarenotrealizedat

first.To

fix

ameasurement

or

connection

problem

where

the

2pipes

that

were

intended

to

connectdonotmatchup,usetwo45degreeelbows.Acombinationoftwo45elbowswill

producealmostanytwistorangledesired.

Two45

elbowscan

makea90

degree

twistor

a

180

degree

twist.

Twopipesthat

didnot

connectbefore

cannowbe

connected

withthe

help

oftwo45

elbows.


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16

ItisalsopossibletoshortenthePVCpipebycuttingandreconnectingitwitharubbercoupling.

Noticethatthepipebelowistoolongtoconnectwiththesmallerpipesattachedtothewall

(seetoppicture).Itwasshortenedandreconnectedusingarubbercoupling(seebottom

picture).


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17

Sizingofthetankandroofwasher

Avarietyofrainwatersystemscanbeconstructedforthesamedownspoutandroof.Hereare

twodifferentsystemsthathavebeeninstalledovertheyearsatthe1100BlockBergenGarden

inBrooklyn.

It

is

generally

better

to

have

asingle

barrel

rather

than

multiple

barrels

because

of

possibleleakagefromthenumerousconnections.The9barrelsintheoriginalsystemhad17

connections.Therewere17locationswhereleakagecouldoccurasopposedto1locationinthe

currentsystem.

Thecapacityofthesystemshouldbedeterminedbytwofactors:thesizeoftheroof,which

determineshowmuchwatercanbecollectedandthesizeofthegarden,whichmeasureshow


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18

muchwaterisneeded.A300gallonverticalcylindricalstoragetankisapproximately42inches

indiameterand51inchestall.A1000gallonpolyethylenetankisapproximately92inchesin

diameterby60inchestallor61inchesindiameterby100inchestall.

Theamountofwateryoucanharvestvariesdependingonthesizeofyourroof.Youwillbe

surprisedhow

much

water

you

will

be

able

to

collect

from

even

the

smallest

roof.

The

rule

of

thumbis600gallonsofwaterperinchofrainperthousandsquarefeetofcatchmentarea.

Notalltherainthatfallscanactuallybecollected. Efficiencyisusuallypresumedtobe75%

dependingonsystemdesignandcapacity. Hereisthebasicformulaforcalculatingthe

potentialamountthatcanbecollected:

(Catchment area) x (inches of rain) x (600 gallons) x (.75)

________________________________________________

1000 square feet

Rememberthataroofcanhaveseveraldownspouts.Yourcatchmentareaonlyconsistsofthe

regionwhere

the

downspout

that

is

connected

to

the

rain

barrel

collects

from.

Pay

attention

to

thegutterandslopeoftherooftodeterminewhichpartisyourcatchmentarea.Inorderto

calculatethecatchmentarea,usemeasuringtapetodeterminethewidthandlengthofyour

roofinsquarefeet.Multiplythelengthandwidthofyourcatchmentareafortheareaofyour

roof.

Thesampleroofshownbelow(seepicturebelow5)hasacatchmentareathatis40feetwide

and30feetlong.Hence,ithasa1200squarefeetroof(40feetwidex30feetlong).Assume

thatitrains2inches.Wecannowplugthisinformationintoourgeneralformula(seeequation

above).

CatchmentArea=1200squarefeet

AmountofRain=2inches

Gallonsofwatercollectedperinchofrainper1000squarefeet=600gallons

Percent

Efficiency

=

75%

or

.75

(1200 square feet) x (2 inches of rain) x (600 gallons) x (.75)

__________________________________________________ = 1080 gallons

1000 square feet


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Thereforea1200squarefootroofwillcollect1080gallonsofwateronadaywith2inchesof

rainfall.Usingthisformulaandyourregionsaveragerainfallnumberscombinedwithan

estimatedwaterneed,youshouldbeabletocalculatetheapproximatesizeofyourtankor

barrelsystem.

Roofwashersizesalsodifferaccordingtothesizeoftheroof.Theruleofthumbisonetotwo

gallonsofroofwashercapacityforevery100squarefeetofcatchmentarea.A1footlengthof

6inchdiameterPVCpipeholds1.5gallons.A1footlengthof4inchdiameterPVCpipeholds

.66gallons.

Wewillusethesame1200squarefootroofshownaboveasanexample.Sincetheruleof

thumbsuggestsonegallonofroofwashercapacityforevery100squarefeetofcatchment

area,thesampleroofwillneed12gallonsofroofwashercapacity.

Ifyouareusing6inchdiameterpipe,usethefollowingformula:

Number of gallons of roof washer capacity

__________________________________

1.5 gallons/ feet

Thesizeofourroofwasheronoursampleroofcanbecalculatedby:

12 gallons of roof washer capacity

______________________________ = 8 feet of 6 pipe

1.5 gallons / feetIfyouareusing4inchdiameterpipe,usethefollowingformula:

Number of gallons of roof washer capacity 12 gallons

____________________________________ = _________________ = 18 feet of 4 pipe

.66 gallons / feet .66 gallons/ feet

Thereforea1200squarefootroofwillneed8feetof6diameterpipeor18feetof4diameter

pipe.Rememberitispossibletoseparatelonglengthsofroofwashersintoseveral,continuous

pipesinsteadofjustonelongpipe.


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20

ConstructionThefirststepoftheconstructionprojectistomakeaplandrawing.Theplandrawingconsiders

thelocation

of

the

downspout

and

the

amount

of

space

available.

Each

system

must

include

thetank,thefirstflushandtheoverflow.Herearesomeissuesthatshouldbeconsideredin

yourplanning:

Themoststableplacetopositionyourbarrelisagainstastablewallonlevelgroundasclose

tothedownspoutaspossible.

Gravitymoveswaterdownhill.Besurethereisavailablespaceforadownwardpitchinall

pipes.

Thebarrelonitsplatformisthehighestpointofthegardenbutthelowestpointofthe

system.

Theoverflowpipeshouldbedirectedtowardaraingardennottowardpathwaysor

structures.

Theoverflowpipeshouldflowfromthebarrelshighestpoint.

Thespigotshouldbeatthebarrelslowestpoint.


25/54

21


26/54

22

Tanks

Tankscanbemadefromallsortsofmaterialssuchascement(seepictureonleft6),metal,

ceramicandwood(seepictureonright7).Intropicalcountries,aterracottatankcanbeused.

Nowintering

tee

is

necessary

for

these

tanks

because

there

is

no

danger

of

freezing.

Fordesignpurposes,bladderscanalsobeusedtostore

waterinsteadoftanks.Bladdersarelarge,flexiblebags

functioninginawaysimilartothewaterballoon(see

pictureonleft8).Thisway,engineerscancreatestorage

tanksinavarietyofshapesinsteadofthetraditional

cylinder.

Thetanksystemincludesthespigot,theinflowpipe,theoverflowpipe,thelidandtheplatform

itrestson.

Spigot:Avarietyofbushingscanbeusedtoconnectthespigot.Itispreferabletouseasingle

reducerbushingbutthatisoftennotpossible.Forexample,thetanksspigotholeis2inchesin

diameter.Thespigotpicturedhereisaballvalvehosebib.Inordertoreducethe2opening

tothespigot,thefollowing3bushingswereused:


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23

Lid:Thelidshouldremainclosedatalltimes.Stillwaterisahavenformosquitolarvae.Inspect

thelidandanyventsannuallyandcleanasnecessary

InflowandOverflowpipes:Sometankscomewithbulkheadfittingsinstalledfortheinflowandoverflowpipes.Forthosethatdont,aholesawisusedtodrillalargeholeinthebarrel.Two

bushingpieces,liketheonespicturedbelow,areusedtofashionabulkheadfitting.

Useamarkertotracetheholeyouwillcutforthethreadedbushings.Maketheholetightto

thethreads.Oncetheholeisprepared,threadthefirstpieceinfromtheoutside.


28/54

24

Threadthesecondpiecefromtheinsideofthetankusingaflexiblewrench.Useguttersealant

tocreateawatertightseal.

Platform:Thepurposeoftheplatformistoraisethetankenoughtogetyourwateringcanunderthespigotandtocreatepressureflowforahose.Spreadathickgravelbaseoveranarea

slightlylargerthantheplatform.Thiswillpromotegooddrainageandallowforfinalleveling

oncethe

platform

is

built.

Astablearrangementofcementcinderblocks,likethisone,makesagreatplatformforsmall

55gallontanksbutisnotidealforlargertanks.Sincetheblockseasilyshift,rotresistant4X4

or6X6lumberlaidoutinalternatingrowsisthebestoptionforaplatform.Steelplatforms

arealsoapossibilitybutaremorecostly.Besuretolevelandcompactthegroundwellwhere

thetankwillsit.

WarningSigns:Donotdrinkthewatercollected.Onlyuseittoirrigateyourgarden.InstalledPVCisinertanditisusedasawatersupplypipe

forhouse

trailers

and

other

homes.

The

possible

contamination

is

almostexclusivelyfromharmfulbacteria.Forwatertomeetdrinking

waterstandardsitmustbetreated,usuallywithchlorine,oftenfiltered

andsometimestreatedwithultravioletlight.Awarningstickerorsign

shouldbeplacedonyourrainbarreltoavoidthepossibilityofanyone

mistakenlydrinkingthewater.


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25

Leaders

Theleadersoftherainwaterharvestingsystemrefertotheseriesofpipesthatleadtothe

tank.Thisincludesthepipethatconnectsthedownspout,thewinteringtee,theroofwasher

systemand

the

pipe

that

connects

the

barrel.

Gravity

keeps

the

water

flowing.

Remember

to

putadownwardpitchonallpipes.Aquarterinchdownforeverylinearfootwillcreateanadequatepitch.Usealevel(seepicturebelow).Itmaybeusefulforsomeonetostandbacktovisuallycheckthe

pitchandhelpyouadjustthepipesasyouarepitchingthem.

Keepthepitchofyourpipeseven

anddownhill. Thepictureontopis

correct.Thepictureonthebottom

hasan

upward

pitch

and

will

create

problems.

Keeppipespitcheddownward.

DONOTpitchpipesupward.


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26

Connectingthedownspout:Ourintentwithrainwaterharvestingistodivertstormwater,storeitforfutureuseandkeepitoutofthesewers.Thereareseveraloptionstodiverttherain

water:inserta3wayteeintothedownspout(seepictureonleft)orconnecttheexisting

downspoutdirectlytotherainbarrel(seepictureonright).Youcandesignyourowncustom

diverteraswell.

Anotherpossibilityistoreplacethedownspoutentirelywithpipesleadingtoyourrainwater

harvesingsystem(seepicturebelowandonthenextpage).


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27

Connectingtothedownspoutisoneofthelaststepsinconstructionofyoursystem.Youdonot

wanttodisconnectyourdownspoutandstartcollectingrainwaterwithanunfinishedsystem.

Winteringtee:Thepurposeofthewinteringteeistoallowthewatertobedirectedbackintothe

sewers

during

freezing

temperatures.

Rain

water

should

not

be

collected

at

that

time

becauseitmayfreezeandcausebreaksinthesystem.Asimplewinteringteeutilizesa

removableplungerhead.Theplungerheadblockswaterflowintothesewerandforcesitto

enterthesystem.Itisremovedduringthewinterandrainwaterwilljustflowstraightdown

intothesewer(seepictureonleftanddiagramonpage4).Complicatedwinteringteesinclude

afilteringsystem.Itoperateswiththesameprinciplebutinsteadofaremovableplungerhead,

thereisaremovablefilterwhichcatchesdebris(seepictureonright).

Roofwashersystem:RefertoRoofwashersonpage30.Connectingthebarrel:RefertoTanksonpage23.


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28

Herearesomeideastohelpyouwiththedesignofyourleader.

INFLOW

1:90elbow

2:4"pipe

3:90elbow

4:45elbow

5:4"pipe

6:45elbow

OVERFLOW

7:2"bushing

8:90elbow

9:2"pipe

INFLOW

1:downspout

2:4"rubbercoupling

3:cap

4:4way

tee

5:rubbercoupling

6:90elbow

7:4"sleeve

8:4"rubbercoupling

9:3waytee

OVERFLOW

10:45elbow

11:90elbow

12:4"pipe

Thisdesignusesaseparateinflowandoverflowpipe.

Thisdesignusesthesametankopeningforboththeinflowandoverflow.


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29

RoofWashers

Rooftopsarepronetocollectleavesanddirt.Theraincarriesallthisdebriswithitasitenters

thegutteranddownspout.Theroofwasherorfirstflushsystemisasimplewaytofilterthe

wateryou

collect.

It

is

aseries

of

pipes

that

storm

water

flows

into

before

entering

the

rain

barrel.Oncetheroofwasherisfull,waterwillbegintofilltherainbarrelwithoutmixingwith

thedirtywatercontainedinthefirstflush.Theappropriatesizeoftheroofwashervaries

dependingonthesizeoftheroof.RefertoSizingofthetankandroofwashersystemonpage

18fordetailsonhowtocalculateroofwashersize.Smallfirstflushsystemscanbeasingle

downwardpipe.However,toaccommodatelargerroofs,firstflushsystemscanbeconstructed

ofmultipledownwardpipes.

Theroofwashermustbeemptied

promptlyafteraraineventandvalve

resetin

the

closed

position

to

be

ready

forthenextrain.Draintheroofwasher

toasafelocation.Includeanotherspigot

orvalveinyourdesigntodrainthefirst

flush.


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30

AnalternativetothecontainermethodoftheroofwasherisadeviceliketheFlowRate

DiverterbySafeRain.Itconsistsofaplasticballattachedtoaspring.Thetopoftheball

containsascreenandamovabletab.Duringarainfallevent,waterthatentersthepipewill

eitherflowintotheballoronitssides(seepictureonleft).Thepurposeofthescreenontopis

tograduallyallowwatertoentertheball.Oncetheballisfilled,itwillsinkdownandblockthe

drain(see

picture

on

right).

Water

can

then

start

filling

up

the

pipe

and

start

entering

the

tank.

Themoveabletabcontrolstheamountofwaterthatenterstheballbycoveringorexposingthe

screenasdesired.Forexample,largerbarrelsthatrequirelargerroofwashersrequireascreen

thatislessexposed.Largeramountsofwaterwillhavetopassthroughthepipebeforetheball

canbefilled.Theballwillhaveasmalldripholetoslowlyemptyoncetherainhasendedto

thenreturntoitsoriginalpositiontobereadyforthenextrainfall.

Enteringrainwater

willflowintothis

pipe.Somewillenter

theball,

making

it

heavierandsomewill

flowpasttheballand

outofthepipe.

Oncetheballis

saturatedwithwater,

it

will

sink

down

and

blockthepipe.Water

willfillupthepipe

andfinallyenterthe

tank.

Thisdeviceallowstheoverflowpipetobeconnectedtotheroofwasherpipe.

Theballisplacedina3wayteewitha

removablecapsothattheballcanbe

takenout.

Water

gradually

enters

theball

through

this

screen.


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31

Hereisanideatohelpyoudesignaroofwasherofyourown.

ROOF

WASHER

1:3waytee

2:6pipe

3:90elbow

4:6pipe

5:3waytee

6:6pipe

7:3waytee

8:6pipe

9:drainvalve

INFLOW

10:6x4rubber

coupling

11:

4

pipe

12:45elbow

13:4pipe

14:45elbow

15:4pipe

16:bushing

OVERFLOW

17:bushing

18:90elbow

19:2pipe

20:90elbow

21:2pipe

ANCHORING22:plumbersstrap

Althoughthisrainwaterharvestingsystemhasagoodroofwasherdesign,itdoesnothaveagood

overflowdesign.Excesswaterwillbackupintotheinflowpipebeforetheoverflowpipestarts

working.Theoverflowpipeshouldalsobethesamediameterastheinflowpipetoavoida

bottlenecksituation.

gradually

enters

theball

through

this

screen.


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32

Overflowpipes

Whentherainbarrelreachesitscapacity,theoverflowpipedischargestheexcesswatersothat

waterwontstartspillingoutfromaroundthelid.Cutaholenearthetopofthebarreland

connectan

overflow

pipe

there.

Be

sure

that

the

overflow

pipe

is

not

directed

toward

water

sensitivestructuresorareaswherewatercancollectanddodamage.Theoverflowpipeshould

bethesamesizeastheinflowpipesothatabottlenecksituationisavoidedduringheavy

rainfalls.

Herearesomeideastohelpyoudesignanoverflowpipeofyourown.

OVERFLOW

1:bushing2:2pipe

3:45elbow

4:45elbow

5:2pipe


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33

Insteadofdirectingwaterbackintothesewer,youcandirectthewaterintoaraingarden,

gravelfilledtrenchorconnectittoadripirrigationsystem.Overflowcanbeturnedintoworks

ofart.Heretheoverflowisturnedintoasmallwatercourse(seepictureonbelow),which

ultimatelyendsinaraingarden.

OVERFLOW

1:2pipe

2:90elbow

3:2pipe

Theoverflowpipeisconnectedbacktothesewer.

Buildingsystemsclosetothedownspoutrequires

lesspiping.


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34

Raingardensaredepressedplotsofland(seepicturesbelow).Itshouldbeatthelowestpoint

inthegardensothatwatercanflowthereeasily.Digadeeptrenchandfillitwith5inchesof

gravelforseepage.Coverthisareawithburlapnettingsothatthesoilwillnotsinkdowninto

thegravel.Placeacoupleofinchesofsoilontopandstartplanting.Onlyplantsabletosurvive

bothdryandsaturatedsoilshouldbegrown.Nativeplantsarealsoencouragedbecausethey

aremore

tolerant

of

local

climate

and

soil

conditions.

These

plants

include

wildflowers,

ferns,

shrubsandsmalltrees.9BrooklynBotanicGardenprovidesathoroughlistofraingardenplants

fordifferentregionsontheirwebsiteat:

http://www.bbg.org/gar2/topics/design/2004sp_raingardens.html

Bioswalesarealternativestoraingardens.Theyaredepressionsinthelandscapewith

collectionsofrock,gravelandvegetationthatactasafilterforwater.Theyeffectivelystrain

silt,inorganiccontaminants,organicchemicalsandpathogens.Thelongerthewateristrapped

insidethe

bioswale,

the

easier

it

is

for

pollutants

to

be

trapped.

They

are

most

commonly

found

surroundingaparkinglotsothatoilrunoffcanbefilteredbeforeenteringthesewersystem.10


39/54

35

Anchoring

Becausetherainbarrelisfairlylightandmaytiporfallwhenitisempty,itisimportantto

anchorthesystemtotheplatformorastructure.Theeasiestmethodtotiedownyoursystem

isto

use

nylon

rope.

Steel

cable

is

also

asolution.

Since

cabling

is

more

complicated,

we

will

illustratethesesteps.

Cutapieceofsteelaircraftcableandslip5cableswedgesinitUsethefirstpieceofcable

swedge(seepicture1)andacrimpingtooltoconnectitintoacircle(2).Itscircumference

shouldbealessthanthecircumferenceoftherainbarrelbutmorethanthatofthelid.Cuttwo

morelongpiecesofsteelcable.Theyshouldbeatleasttwicetheheightoftherainbarrel.Use

onecableandslipitthroughtwoofthemetalcableswedgesthatarealreadyonthecircle.

Makingsurebothlengthsofcableareeven;usethecrimpingtooltosecurethemetalswedges

inplace.Dothesamewiththeothercableandtwometalswedges(3).

Screw

a

metal

eyebolt

into

each

of

the

four

corners

of

your

platform.

Connect

a

turn

buckle

to

eachmetaleyebolt(4).Placetheseriesofcablesontoyourrainbarrel.Thecircleshouldbeon

topoftherainbarrel(5).Thefourhangingendsshouldbefacingeachcorneroftheplatform.

Looptheendsofthecablesintotheturnbuckle(6).Useametalswedgetosecuretheloop.Do

thisforallfourcorners.Finally,twisttheturnbucklesuntilthemetalcablesaretaut(7)tofinish

securingyourrainbarrel(8).


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36

Forcinderblockplatforms,nailathickwoodenplankontopandusetheeyeboltmethod

mentionedabove.

Prefabricatedsteelbracketsaregenerallyusedtoanchorhorizontaltanks.


41/54

37

Itisagoodideatoanchorpipesaswell.Ifthepipeishuggingtherainbarrel,anchorthepipeto

thatplatformusingcable(seepicture1),perforatedplumbersstrap(2)orothermethods.

Pipesthat

are

directly

against

the

wall

of

abuilding

can

be

secured

to

the

wall

using

plumbers

strapattachedwithtapconscrews,whichsealtheholedrilledinthewalltoavoidleaks(2).


42/54

38

DripIrrigation

Dripirrigationsystemsreducewateruse.Smallamountsofwateraresuppliedtothebaseof

plants.Sincethewaterisapplieddirectlytothesoil,ratherthanontotheplant,evaporation

fromleaf

surfaces

is

eliminated.

The

water

is

also

placed

where

it

is

needed

rather

than

sprayed

overtheentiregarden.

Withadripsystem,waterflowsintoaseriesofthinflexiblehoselines.Theseirrigationhoses

havetinyholesatevenintervals.Thesehosesareplacedonthesurfaceorbeneathalayerof

mulch.Whenwaterentersthesystem,itslowlytricklesoutoftheseholesandwaterstheroots

ofplants(seepicturesbelow11).Theoverflowofrainwaterharvestingsystemsissometimes

connectedtothesesmallerpipes.

Tubingcomesinmanysizes(seepicturesbelow12).Itisusedtogetthewaterfromthesource

tothegarden.Avarietyoffittingsareavailabletogoaroundcornersandtoconnectpieces.


43/54

39

Inmostcases,nospecialtoolsorskillsareneeded.Plasticpipeispunchedwithaninexpensive

tubepunchthatassurestheproperholesize.Spaghettitubessnapintothehole.Nogluingis

required.Becausetheholesaresmall,theycaneasilybepluggedifyouputoneinthewrong

place.

GravityFeed

Drip

Irrigation

Kits

are

used

to

connect

to

rain

barrels

and

rainwater

harvesting

systemswherethewaterpressureislow(seepicturebelow13).Thissystemusessmallinch

valvesinsteadofemitterstoavoidtheproblemofcloggedemitters

DripIrrigationsystemsneedplanning,butareneitherexpensivenordifficulttoinstall.Most

dripirrigationsupplierswillhelpyoudesignasystemtobestmeetyourgardeningneeds.Drip

systemsrequireperiodicmaintenance.Checkregularlyforleaksandbrokenconnections.


44/54

40

FiltrationSystems

This rainwaterharvestingsystemalreadyhas twomeansof filtration,oneat thegutter (see

picture1)andtheotherattheroofwasher(2).

Thisgutter screen that isputat themouthof thedownspout (see

picture on right) prevents leaves and other large debris from

enteringthesystem.Ifyouwanttobuyafilter,twochoicesareRain

Keeper Downspout filter for smaller roofs and the Rain Keeper

Downspoutcollectionfilterforsmallersystems.RefertoWhereto

obtainsuppliesonpage11formoreinformation.

Thegutterfiltersout

leaves

and

large

debris.

Theroofwasherfiltersoutthe

particulatematterfoundon

rooftops.

1

2


45/54

41

Treatment

Duringwarmweather,bacteriamaygrowinsidethestoragetank.Organicmatteralsoposesa

problemasalgaeorothercontaminantsmaygrowinstoragetanks.WRGrecommendsaddinga

smallamount

of

chlorine,

in

the

form

of

unscented

household

bleach,

to

your

water

storage

tank.Donotusebleachwithanyadditiveslikefragrancesorsofteners.Alogshouldbekeptto

ensuretheproperadditionofthechemical.Storelogwithbleachcontainer.Pleaseremember

toweargloveswhenhandlingbleach,tostorebleachinacool,dryplaceandtolabelbottle

clearlytoavoidimproperuse.Onthe1stofeachmonth,addasmallamountofbleachtoeach

waterstoragecontainer.Ifthetankisemptiedandrefilledinlessthanonemonthstime,an

applicationofbleachshouldbeaddedtothetankwhenitrefills

TankSize AmountofBleachtoAdd

1000gallons 1/3cup

750gallons 1/4cup

500gallons 3tablespoons

50gallons 2teaspoons

Regularlyemptyingtheroofwasherandtheadditionofasmallamountofbleachtoyourtankwill

ensurethe

water

is

safe

for

watering

vegetables.

The

water

stored

in

the

tanks

is

for

irrigationpurposesonly. Itissafetouseonvegetablesandotherplantsinthegarden,butitisnotsafeto

drink.Thequalityofthiswaterdoesnotcomplywithlocalandnationaldrinkingwaterstandards.


46/54

42

Aesthetics

Themostbeautifulsystemiscarefullyconstructedandincorporatesacarefullythoughtout,

welldesignedandinstalledplumbingsystem.

Lars

Chellberg,

CENYC

staff

member

Althougharainbarrelisconsideredbysometobeunsightly,itiseasytobeautifyyourrain

waterharvestingsystem.PVCpipesandtankscanbecoveredbyplantsorpainted(seepictures

below).

AgazeboatthisSeattlecommunitygardencoversanundergroundcisternthatstores5,000

gallonsof

collected

rainwater

(see

picture

below).


47/54

43

Promotingthesustainablepracticeofrainwaterharvestingisalsoimportant.Forexample,NYC

communitygardensuseaThisgardenharvestsrainwatersign(seepictureonright),agood

ideatoputinfrontofyoursystem.Haveprintedinformationforpeopletolearnmoreabout

rainwater

harvesting

like

this

Water

Resources

Group

brochure

(see

picture

on

left).

SometimesitisnecessarytobreaksomebasicRWHrulesforaestheticreasons.Thisrainwater

harvestingsystemhasaninflowpipethatispitchedupwardwhichmeansthatitmustrain

enoughforthewatertofilluptheroofwasherandtheinflowpipebeforeitcanenterthetank.

Thiswasdonesothattheroofwashercouldbepositionedbelowthebrickwallandnot

interferewiththetreelimbortheneighborsviews.


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44

RoofingMaterial

Rooftopsareessentialtoanyrainwaterharvestingsystem.Populartypesofroofinginclude

corrugatedmetaldecking,shingles,rolledasphaltandcedarshake.

Corrugatedmetaldeckingcancomeintwo

forms zinccoatedorhotdippedgalvanized.

Because,zinccoatedroofsrusteasily,hot

dippedgalvanizedroofsaremorepopular.

Theseroofsareconstructedsimplybynailing

downwithsealingwasherstoyourstructure

orscrewing.Applyguttersealantonanynail

orscrewtomakesurewaterdoesntleak

fromthesespots.Metalroofsprovidegreat

structuralsupportforlongamountsoftime.It

hasthe

highest

efficiency

rate

when

it

comes

torainwaterharvestingbecauseofits

waterproofsurface.Itsonlydownfallisthe

noisefactor.Itgetsveryloudwhenrainwater

clasheswiththerooftop.Itisanidealroofing

materialfornonresidentialstructures.

Shinglesaresmallpiecesofoverlappingwoodorslate.Placeainch

widepieceofplywoodontopofthestructure.Startnailingshingles

inahorizontal,overlappingfashionstartingfromthegutterline.

Workyourwayuptothetopofyourroof,makingsureyournextrow

overlapsthepreviousrow(seepictureonleft14).

Rolled asphaltormodifiedbitumen roofsoccurmost commonlyon flatter rooftops.A large

sheetofasphaltissimplyglueddownwithtarorplastic.Asphaltroofs

can either have a granular surface or a smooth surface. Although

granular surfaces are slightly less efficient in catching rain water

becauseitiseasilytrappedinthepiecesofgroundglass,itispreferred

over smoother roofs.Granular roofswear slowly, resist cutting and

keep UV rays from degrading it. Typically, a few years after the

granularroofisinstalled,itispaintedwithaluminumtolockingrainsthatmayhavefallenloose

(see

picture

on

right

15

).

Cedarshakeorwoodenroofsareinstalledinavertically

overlappingfashion.Woodistheleastefficientincatchingrain

waterbecauseitisporous.However,oncethewoodissaturated,

itwillnolongerabsorbwater(seepictureonleft16).


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45

SeasonalMaintenanceToensureyourhealthandsafetytheWaterResourcesGrouprecommendsthefollowingseasonal

maintenanceschedule

for

keeping

your

rainwater

free

of

contaminants.

Spring

Closespigot Redirectroofwaterfromthedrainpipebackintotankstoragesystembyreplacingthe

inlineplungerorchangingthepositionofthevalve

Cleananywinterdebrisfromgutters,leaderinletsandroof Repairanyleaksinbarrelortanks Inspectandcleanbarreltops Fillsystemwithafewinchesofwatertocheckhoseconnectionsforleaks Inspectrope/cableretainerstoassurethatbarrelsaresecure Besurethatyourtankislabeledwithadonotdrinkthewater signinallappropriate

languages

Tohelpensurethatchildrendonotdrinkthewaterremovethevalvefromspigotandstorewithtools

Summer

Keeptheroof,guttersandleaderinletsclearofdebris,checkmonthly Inspectventsattopofeachbarreltoinsurethattheyarecleanandintact Visityoursystemduringaheavyrainorshortlyaftertocheckforleaksandoverflow

problems.

Anywaterfromtheoverflowsystemshoulddrainwithin24hoursofarainfall;ifpuddlesform,youshouldmovetheoutflowpipetoamoreporoussiteorconsider

installingasmallraingarden

Inspectpipesandconnectorsregularlyforanydamageordisrepair Checkmanwayhatchontopofyourtanktomakesureitissecurelyclosed

Fall

RemoveplungerfromthePVCjointtoredirectwaterintothedrainpipetothesewer Emptywaterfromtheentiresystem roofwasherandtank Openmainvalveofstoragetankandrainbarrels Openvalveonroofwasher. Valvesshouldremainopenallwintertokeepwaterfrom

freezinginsystem

Disconnectleaderfromsystemandreroutewaterasnecessaryforparticularsystem Coveranyopeningsinleaders


50/54

46

LivingwiththeRWHSystemNowthatyouhavebuiltyourrainwaterharvestingsystem,youhavehelpedtoconserveoneof

theEarths

most

valuable

resources.

A

rain

barrel

is

not

something

you

build

and

walk

away

from.Itisimportanttomakesuretherearenoleaksinyourbarrelandtodrainthefirstflush

aftereverystorm.

Remembertodrainyourroofwasherandtankduringthewinterandtotakeoutyour

winteringtee!FreezingwaterwillBREAKthesystem.Thecracksseeninthetwopictures

belowarefromleftoverwaterfreezingandexpanding.

Ifproperlybuiltandmaintained,yourrainwaterharvestingsystemwilllastmanyyears.Even

thesmallest

tanks

will

save

thousands

of

gallons

of

water.

It is essential to learn how tomanage

your water usage. Seventy percent of

residential water use goes to outdoor

activities. One third of that water is

wasted (see diagram on right17).Using

pumpsorsprinklerstowaterplantsare

one of the most inefficient ways to

irrigate.Plantsonlyneedtobewatered

at the roots. Sprinklers relentlessly

wastewaterby randomly shootingoutwater to tree branches or leaves.Drip

irrigation systems with outlets placed

strategicallynexttoplantrootsarethemostefficientwaystoirrigate.


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47

ExistingRWHSystemsOrganicGardeningMagazinehasbeensponsoringconstructionofrainwaterharvesting

systemsin

community

gardens

since

2007.

Their

Waterworks

Project

funded

30

systems

in

the

past2years.Lookingatexistingrainwaterharvestingsystemsandtalkingtocommunity

gardenersmayassistyouinbuildingyourown.LocationsintheUSAandCanadainclude:

AlemanyFarm SanFrancisco,CA

AshviewCommunityGarden Atlanta,GA

AspenFarms Philadelphia,PA

BoydStreetUrbanFarm Portland,ME

BradnerGardensParkSeattle,WA

BrentwoodCommunityGarden Portland,OR

ChildrenGarden Camden,NJ

CitySeeds

Urban

Farm

St.

Louis,

MO

DiasyFloresNewYork,NY

TheFarmGardenattheEarlyChildhoodEducationCenter Columbus,OH

FremontCommunityGarden Sacramento,CA

TheGardenofDreams NewYork,NY

GlobalGardens Tulsa,OK

GlorylandCommunityGarden,Detroit,MI

GrowingGreenYouthGarden,Buffalo,NY

GuadalupeMontessoriSchool,SilverCity,NM

HopeCommunityGarden Toronto,ONCanada

MarigoldMeadows

Phoenix,

AZ

MasterPeaceYouthandCommunityGarden Riverdale,MD

OurSaviourCommunityGarden Dallas,TX

The1100BlockBergenStreetGarden Brooklyn,NY

UrbanMinistryCenter Charlotte,NC

WasatchCommunityGardens SaltLakeCity,UT

WoodlawnGarden Portland,OR

XochiquetzalPeaceGarden Chicago,IL

Formoreinformationonthesegardens,visittheirwebsiteat:

http://www.organicgardening.com/feature/0,7518,s1210153111X2X34,00.html

ThisguidecanbefoundonCENYCswebsiteat:

http://www.cenyc.org/openspace/rainwater/RWHHowTo.pdf


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48

10Ways

to

Conserve

Water

1.Turnoffthefaucetwhenbrushingyourteeth,washingyourfaceandshaving.

2.Fixanyleakysinks,toiletsorshowerheads.

3.Washonlyfullloads forclothinganddishes.

4.Donotrunwatertothawmeats.

5.Waterplantsattheroots.

6.Takeshowersinsteadofbaths.

7.Replaceshowerheadsandsinkaeratorswithlowflowones.

8.Useapitchertostorecoldwaterintherefrigeratorinsteadofrunningthetapeverytime.

9.Waterplantsduringearlymorningsandlateafternoonstoreduceevaporation.

10.Donotflushthetoiletunnecessarily.Disposeofbugs,cigarettebuttsandtissuesanother

way.18

19

20

TheWaterResourcesGroup(WRG),acoalitionofNYCgreening&communitygardengroupsis

dedicatedtothepreservationofNYCwaterresourcesthroughgardening,ecologicaldesignand

educationprograms.WRGisinstallingrainwaterharvestingsystemsingardensacrossNYCto

conservewaterandpreventpollution.Formoreinformationonhowyoucanhelpconserve

waterinNewYorkCity,visittheWaterResourcesGroupwebsiteat

www.waterresourcesgroup.org.TheWaterResourcesGroupmeetseverysecondThursdayof

themonthat10a.m.attheCouncilontheEnvironmentofNewYorkCity,51ChambersStreet,

Room214.Allarewelcometoattend.

Ifyouhaveanyquestionsregardingtheconstructionofyourrainwaterharvestingsysteme

mailLenny

Librizzi,

Assistant

Director

of

Open

Space

Greening

at

CENYC

at

[email protected].


53/54

49

1Hasse,Rolf.Rainwaterreservoirsabovegroundstructuresforroofcatchment.WelcometoEnergy.19November2003.20

June2008

2An

introduction

to

rain

water

harvesting.

The

WWW

Virtual

Library

on

Urban

Environmental

Management.

9May

2008.

20

June2008

310,000RainGardens.2008.20June2008

4Water.TheNewYorkObserver.21April2008:G10.

5Anintroductiontorainwaterharvesting.TheWWWVirtualLibraryonUrbanEnvironmentalManagement.9May2008.20

June2008

6RhizomeCollective.EcoWarrior.28Nov2007.11July2008

7OakWhiskeyBarrel.RainBarrelbyAaron.2003.11July2008

8 Products.RainDropsCisternsRainwaterHarvestingandStorage.23June2008.11July2008

9RainGarden.Wikipedia:TheFreeEncyclopedia.12June2008.20June2008

10 Bioswales.Wikipedia:TheFreeEncyclopedia.3April2008.20June2008

11ChapinWatermaticsInc.11July2008

12Dripdepot.11July2008

13Dripdepot.11July2008

14Roofing.

Sam

Siding

Home

Improvement.

20

June

2008

15LexisCoatings.20June2008

16Cedar.HynesHomeImprovement:TheSignofQuality.11July2008.

17HydrapureWaterSolutions.Hydrapure.11July2008.

18Lenz,Ericka.10easywaystoconservewater.GaiamLife YourGuidetoaBetterLife.20June2008

1910waystoconservewater.EtowahWaterandSewerAuthority.2February2008.2008June2008

20TenWaysToConserveWaterAroundTheHouseAndHelpTheEnvironment.TheGoodHuman.2July2007.20June2008.

ThismanualwasputtogetherbyJuliaLeung,LennyLibrizzi,AssistantDirectorofOpenSpace

GreeningatCENYCandLarsChellberg.


54/54

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CouncilontheEnvironmentofNYC

51ChambersStreet,Room228

NewYork,

NY

10007

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rainwater harvesting 101 - grow new york city

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