Los Angeles Rainwater Harvesting Manual

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Los Angeles Rainwater Harvesting Manual

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  • 1. City of Los AngelesRainwater Harvesting Program A Homeowner’s “How-To” Guide November 2009 · 1st Edition
  • 2. City of Los Angeles Rainwater Harvesting ProgramTable of ContentsAcknowledgments ............................................................................ii How to Build a Rain Garden ..............................................................9Introduction .....................................................................................1 Before.you.Begin....................................................................................9Background............................................................................................ 1 Assess.Potential.Sites.............................................................................9What.is.Rainwater.Harvesting?..............................................................1 Design..................................................................................................... 9Who.Should.Use.this.Manual?...............................................................1 Perform.a.Soils.Infiltration.Test..............................................................10 Calculate.Runoff.and.Rain.Garden.Size..................................................10Why Harvest Rainwater? ..................................................................1 Direct.Water.Flow. .................................................................................11 .To.Protect.Our.Bays.and.Ocean..............................................................1 Choose.your.Plants.................................................................................11To.Reduce.Energy.Demands...................................................................2 Build.your.Garden..................................................................................12To.Practice.Water.Conservation.............................................................2To.Recharge.Groundwater.Supplies.......................................................2 Other Rainwater Harvesting Options ................................................13Overview of Rainwater Harvesting ...................................................2 Rainwater Harvesting System Maintenance ......................................14Redirection.Options. ..............................................................................2 . Rain.Gutters............................................................................................ 14What.is.a.Rain.Barrel?............................................................................2 Downspouts........................................................................................... 14What.is.a.Rain.Garden?..........................................................................3 Rain.Barrels............................................................................................ 14 Rain.Gardens.......................................................................................... 15How to Harvest Rainwater on Your Own ...........................................3Assess.your.Site......................................................................................3 Where Can I Get More Information? .................................................15Redirection.Criteria.Checklist.and.Safety.Considerations.......................3 The.City.of.Los.Angeles. .........................................................................15 .How.to.Measure.a.Slope........................................................................4 Additional.Resources..............................................................................15 Publications............................................................................................ 16How to Redirect a Downspout to a Pervious Area .............................5Before.you.Begin....................................................................................5 Glossary of Terms .............................................................................16Redirection.Procedure............................................................................6How to Redirect a Downspout to a Rain Barrel .................................7Before.you.Begin....................................................................................7Redirection.Procedure............................................................................8 Los.Angeles.Rainwater.Harvesting.Program i
  • 3. Acknowledgments Chuck Wolf, Mike D’Annucci, Rachel Stevens,.Lisa Cuellar, Erika Kennelley A.special.thanks.to.the.following.for.their. contributions.to.the.City.of.Los.Angeles. S. Groner Associates, Inc.: Rainwater.Harvesting.“How-To”.Guide: Public Outreach Consultant Team Erica Hooper - Project.Manager City of Los Angeles Bureau of Sanitation Jackie Wei, Codi Harris Executive Management: Enrique Zaldivar - Director Community Reviewers: Traci Minamide -.Chief.Operating.Officer Green Gardens Group (G3) Varouj Abkian -.Assistant.Director Pamela Berstler, Marilee Kuhlmann Adel Hagekhalil - Assistant.Director Heal the Bay Alex Helou - Assistant.Director Mark Gold, Kirsten James, Shahram Kharaghani - Program.Manager,. Meredith McCarthy Watershed.Protection.Division Los Angeles & San Gabriel Rivers City of Los Angeles Bureau of Sanitation Watershed Council Rainwater Harvesting Program Team: Nancy Steele, Edward Belden Wing Tam - Program.Manager, Watershed.Protection.Division. Los Angeles Department of Water and Power Michelle Vargas - Public.Information.Officer,. Tom Erb, Andy Niknafs Public.Affairs.Office. North East Trees Joyce Amaro - Stormwater.Public. Hannan Awad Education.Manager,. The River Project Watershed.Protection.Division. Melanie Winter Watershed Protection Division Kosta Kaporis - Environmental.Engineer, Santa Monica Bay Restoration Commission Daniel Loo - Associate.Engineer Sean Bergquist, Shelley Luce Majid Sadeghi - Associate.Engineer The Surfrider Foundation Ammar Eltawil - Associate.Engineer Paul Herzog Deborah Deets - Landscape.Architect TreePeople Malcolm Pirnie, Inc.: Andy Lipkis, Rebecca Drayse, Lead Consultant Team Deborah Weinstein, Edith Ben-Horin, Catherine Tyrrell - Project.Manager Jason Schmidt, Lisa CahillLos.Angeles.Rainwater.Harvesting.Program ii
  • 4. Introduction impervious.surface.such.as.a.sidewalk,.driveway. or.parking.lot..Background Rainwater.harvesting.is.the.process.of.inter-The.City.of.Los.Angeles.Rainwater.Harvesting. cepting.rainwater.from.a.roof.(or.other.surface).Program.is.designed.to.help.homeowners.learn. and.putting.it.to.beneficial.use..By.implement-to.capture.rainwater.for.beneficial.use,.and. ing.the.harvesting.techniques.in.this.guide,.reduce.the.amount.of.rainwater.flowing.from. homeowners.gain.an.extra.water.supply.while.their.roofs.into.the.storm.drain.system...The. simultaneously.reducing.the.pressure.on.our.Program.calls.for.disconnecting.downspouts. limited.water.supplies.that.discharge.to.impervious.areas.and.redirect-ing.them.to.areas.where.rainwater.can.perco- Who Should Use this Manual?late.into.the.soil,.or.collect.into.rain.barrels. This.guidance.manual.will.help.homeowners.Due.to.heavy.groundwater.usage.in.Southern. implement.the.first.steps.of.harvesting.rainwa-California,.approximately.3.2.million-acre.feet. ter...It.contains.“How-to”.information.for.the.of.space.are.available.for.groundwater.re- homeowner.interested.in.disconnecting.down-charge..That.is.equal.to.12,000.Rose.Bowls.filled. spouts.to.capture.and.use.rainwater...By.follow-to.the.top.with.water..A.recent.study.described. ing.the.step-by-step.instructions.homeowners.soil.conditions.in.most.of.the.Southern.Cali- can:.(1).disconnect.existing.downspouts;.(2).fornia.region.as.highly.permeable,.allowing.for. extend.downspouts.to.areas.that.can.infiltrate.rapid.infiltration.into.groundwater.basins1...The. rainwater;.(3).install.a.rain.barrel;.and.(4).rainwater.harvesting.process.described.in.this. construct.a.rain.garden.or.other.infiltration.“How-To”.Guide.will.help.increase.local.water. mechanism...Homeowners.looking.to.imple-resources.by.promoting.groundwater.recharge. ment.additional.rainwater.harvesting.methods,. or.seeking.supplemantal.“How-to”.or.trouble-What is Rainwater Harvesting? shooting.information.should.refer.to.Additional.Many.residential.and.commercial.properties.in. Resources.provided.in.this.guide...The.program.the.City.of.Los.Angeles.are.fitted.with.down- website.(www.LARainwaterHarvesting.org).will.spouts...When.it.rains,.water.runs.off.roofs,. be.updated.with.useful.information.as.well.through.these.downspouts.and.usually.onto.an.1 ..Natural.Resource.Defense.Council.Technical.Report..A.Clear.Blue.Future:.How.Greening.California.Cities.Can.Address.Water.Resources.and.Climate.Challenges.in.the.21st.Century...August. © 2009 G3LA2009. Los.Angeles.Rainwater.Harvesting.Program 1
  • 5. Why Harvest Rainwater? Using.rainwater.to.water.plants.helps.conserve. dwindling.drinking.water.supplies.To Protect Our Bays and OceanWhen.rainwater.flows.from.a.downspout.onto. To Recharge Groundwater Suppliesour.sidewalks,.driveways.and.streets,.it.collects. Approximately.40%.of.Southern.California’s.a.variety.of.pollutants...By.capturing.rainwater. drinking.water.comes.from.groundwater...Har-that.falls.on.roofs,.landowners.help.reduce.the. vesting.rain.water.and.allowing.it.to.infiltrate.amount.of.runoff.ultimately.reaching.the.Santa. into.the.ground.replenishes.our.groundwater.Monica.or.San.Pedro.Bays,.and.thus.aid.in.im- supplies.proving.the.quality.of.our.local.surface.waters. Overview of Rainwater HarvestingTo Reduce Energy Demands Redirection OptionsThe.State.of.California.Energy.Commission. The.City.suggests.redirecting.stormwater.runoff.reported.that.water-related.energy.consump- from.downspouts.to.either.a.rain.barrel.or.an.tion.in.California.accounts.for.nearly.20%.of.the. on-site.pervious.area.such.as.a.flower.bed.or.State’s.electricity,.30%.of.its.natural.gas,.and. rain.garden.as.“first-steps”.in.the.rainwater.requires.about.88.billion.gallons.of.diesel.fuel. harvesting.process...There.are.many.more.every.year.2...One.inch.of.rain.falling.on.1,000. features.that.can.be.implemented.on.a.residen-square.feet.of.rooftop.produces.more.than.600. tial.property.to.capture.and.utilize.rainwater...gallons.of.water...If.homeowners.replaced.this. Please.refer.to.the.Sections:.Other.Rainwater.amount.of.potable.water.with.captured.rain. Harvesting.Options.and.Additional.Resources.water,.energy.consumption.in.the.State.should. for.more.rainwater.harvesting.ideas.be.reduced. What is a Rain Barrel?To Practice Water Conservation Rain.barrels.store.rainwater.from.roofs.for.California.has.entered.an.era.of.increasing. reuse.in.landscape.irrigation...Rain.barrels.water.scarcity,.coupled.with.projections.of. are.containers.typically.made.of.a.heavy.duty.increased.temperatures.up.to.10.degrees. plastic.and.can.range.in.size.from.the.standard.Fahrenheit.by.the.end.of.this.century.1.. 55.gallons.to.more.than.80.gallons...Eco-friendly.2 ..The.State.of.California.Energy.Commission...California’s. rain.barrels.assembled.from.recycled.food.bar-Water-Energy.Relationship.Final.Staff.Report...November.2005.. rels.or.manufactured.from.recycled.plastics.are.(http://www.energy.ca.gov/2005publications/CEC-700-2005-011/CEC-700-2005-011-SF.PDF) available.to.consumers... Los.Angeles.Rainwater.Harvesting.Program 2
  • 6. Key.components.of.a.rain.barrel.include.the. •. Rain.barrels.must.be.accessible.for.periodic.following: cleaning.•. A.screen.to.keep.debris.and.mosquitoes.out Information.on.where.to.purchase.a.rain.bar-•. A.spigot rel.and.rain.barrel.pricing.can.be.found.on.the.•. An.overflow City’s.website.at:..•. A.connector.for.linking.multiple.rain.barrels. www.LARainwaterHarvesting.org (if.desired). What is a Rain Garden?Rain.barrels.are.typically.placed.below.down- Homeowners.can.maximize.both.environmen-spouts.and.must.meet.the.following.require- tal.and.economic.benefits.by.installing.a.rain.ments: garden.in.place.of.a.grassy.or.impervious.area...•. Rain.barrels.should.not.allow.UV.light.pen- A.rain.garden.is.a.shallow.depression.that. etration.in.order.to.prevent.algae.growth; captures.rainwater.and.allows.it.to.soak.into.•. Rain.barrels.must.be.covered.and.any.open- the.ground...Plants.help.to.filter.the.rainwater. ings.must.be.screened.to.prevent.mosquito. as.it.moves.through.the.soil.layer...A.rain.garden. breeding;.and is.most.often.planted.with.native.species.creat- ing.a.natural.ecosystem.on.properties.where. Downspout birds,.butterflies,.and.beneficial.insects.thrive... Overflow Rain.gardens.also.capture.sediments.carried.by. Screen Valve rainwater,.preventing.them.from.clogging.the. stormdrains...Incentives.for.creating.rain.gar- dens.are.provided.by.the.Los.Angeles.Depart- Barrel ment.of.Water.and.Power.(LADWP).through. Swale their.Residential.Drought.Resistant.Landscape. Incentive.Program...Also.called.the.cash-for- grass.program,.LADWP.pays.single.family. Spigot residential.customers.$1.for.each.square.foot. Multi-barrel of.grass.removed.and.replaced.with.drought. © 2009 G3LA Connector tolerant.plants,.mulch.and.pervious.areas...The. program.is.dependent.on.budget.availability... A.swale.directs.water.from.the.downspout.to. For.more.information.about.the.cash-for-grass. the.rain.garden..Many.swales.use.rocks.that.A typical rain barrel set up program,.call.LADWP..(888).376-3314. create.a.dry.creek.bed.look. Los.Angeles.Rainwater.Harvesting.Program 3
  • 7. How to Harvest Rainwater As.a.guideline,.locate.downspouts:on Your Own •. At.least.3.feet.away.from.public.sidewalks;. •. At.least.5.feet.away.from.property.lines;Assess Your Site •. At.least.5.feet.away.from.house.foundations. 300 ft2Preparing.a.site.sketch.will.help.to.determine. and.crawl.spaces,.assuring.at.least.a.2%.slope.downspouts.to.disconnect...Begin.by.drawing. away.from.the.home;an.outline.of.the.home.from.a.bird’s.eye.view... •. At.least.6.feet.away.from.basement.walls.Walk.the.perimeter.and.mark.the.location.of. Downspoutsall.downspouts.on.your.sketch...Note.which. How to measure a slope:downspouts.are.connected.to.rain.gutters;. Tie.a.level.string.to.two.stakes.pounded.into.the.these.downspouts.are.candidates.for.discon- ground...Make.certain.that.the.string.attached.nection..Draw.in.roof.lines,.and.estimate.the. to.the.uphill.stake.is.at.ground.level...Measure. Figure 1:.Example.sketch.of.sitesquare.footage.of.the.roof.area.(Figure 1). the.distance.between.the.stakes...This.is.consid- ered.the.width...Measure.the.distance.from.the. Example of Roof Area Calculation:Redirection Criteria Checklist and Safety string.on.the.downhill.stake.to.the.ground...This. Lr.=.25.ft Lt.=.10.ftConsiderations is.the.height...Make.certain.that.the.height.and.It.is.suggested.that.the.following.list.of.condi- width.are.the.same.units...Divide.the.height.by. Wr,.Wt.=.10.fttions.are.met.in.order.to.safely.redirect.a.down- the.width.to.get.the.slope...Multiply.this.by.100.spout.from.a.roof.to.a.pervious.area.without. to.obtain.the.percent.slope..(Figure 2) Roof.Area.=.(Lr.x.Wr).+.1/2(Lt.x.Wt).=.damaging.building.foundations,.or.flooding.a. . 250.(square.feet).+.50.(square.feet).=.basement.or.neighboring.properties. . 300.(square.feet)As.a.guideline,.direct.downspouts: Height ÷ Width = Y•. To.gently.sloped.areas.(preferably.10%.slopes. Example of Slope Calculation: Downhill Y x 100= % slope Uphill or.less.–.See.How.to.measure.a.slope); Stake Stake•. To.areas.sloping.away.from.buildings; Height.=.6.inches.=.0.5.feet Width 10’•. To.rain.gardens.(See.How.to.Build.a.Rain. Width.=.10.feet String Garden); 0.5.feet.÷10.feet=.0.05•. Never.above.septic.tanks; Height 6”•. Never.to.areas.that.experience.ponding; 0.05.×100.=.5% Slope•. Never.to.fill.areas. Figure 2:.How.to.measure.a.slope Los.Angeles.Rainwater.Harvesting.Program 4
  • 8. How to Redirect a Downspout to a Pervious AreaBefore you BeginPrepare all of the tools and materials that you need. It is best to use Hacksaw Tin snipsdurable, gutter-grade materials, such as ABS Schedule 40 plastic options. Drill BracketOther materials such as corrugated black plastic, PVC pipe, or dryer hosecan be used but tend to be less durable. Consult a home and gardenspecialist when purchasing materials for further assistance. See the listbelow and Figure 3 for tools and materials you will need. Be sure to Screw driver Needle-nose Tape measurewear safety glasses. Elbow pliers Downspout extension Tools: Materials: Sheet metal Safety glasses • Hacksaw • Downspout Splash screws • Tin snips extension guard • Drill • Sheet metal screws • Needle-nose pliers • Elbow Figure 3: Materials and tools for redirecting the downspout or crimpers • Bracket • Tape measure • Splash guard Gutter • Screwdriver or nut driver • Safety glasses DownspoutSelect downspouts to disconnect that are connected to a rain gutter(Figure 4). Some homes in the City of Los Angeles are not fitted with raingutters. If a home does not have rain gutters along the perimeter of the Extensionroof, homeowners might consider installing them. This guidance manualdoes not provide information on how to install rain gutters becausethese tasks involve roof seals and require professional expertise. Figure 4: Rain gutter and downspout Los Angeles Rainwater Harvesting Program 5
  • 9. Redirection Procedure Redirecting a downspout to a pervious area is a simple procedure. Step 1: Mark approximately 12 inches from the ground to the downspout. This height should work for up to a 6 foot extension. Cut the downspout higher for longer extensions. 12” Step 2: Using a hacksaw, cut the downspout No basement at the mark. Remove the cut piece. You may extension 2’ need tin snips to smooth the material. Step 3: Attach the elbow over downspout. If Basement extension 6’ the elbow does not fit over the downspout, use crimpers or needle-nose pliers to crimp theSteps 1-2 ends of the cut downspout and slide it inside Step 4 the elbow. Attach the elbow to the downspout with screws; it might help to pre-drill holes. For additional stability, consider securing the elbow to the building with a bracket. Step 4: Measure and cut the downspout exten- sion to the desired length. Attach the extension to the elbow by slipping the extension over the end of the elbow. Step 5: Use screws to attach the extension to the elbow; it might help to pre-drill holes. For additional stability consider resting the extension on a support like a cinder block. To prevent erosion, place a splash guard at the end of the downspout or direct the extension to aStep 3 swale. Step 5 Los Angeles Rainwater Harvesting Program 6
  • 10. How to Redirect a Downspout to a Rain Barrel Before you Begin Make a list of the tools and materials needed. The installation of a rain barrel requires materials for the downspout disconnection, and materi- als to build a platform that the barrel can sit on, such as wood or cinder blocks. Homeowners may also need an additional strap to secure the barrel. Be sure to wear safety glasses. Tools: Materials: • Hacksaw • Downspout • Tin snips extension • Drill • Sheet metal screws • Needle-nose pliers • Elbow or crimpers • Bracket • Tape measure • Splash guard • Screwdriver or nut • Wood/cinder blocks driver • Securing strap • Level • Safety glasses You can transfer water from the rain barrel to a garden by filling a water- ing can, connecting a garden hose, or installing a manual drip irrigation system. Water pressure at the rain barrel spigot will depend on the level of the water in the rain barrel. The higher the water level, the greater the amount of pressure. You can also improve flow through a hose at- tached at the rain barrel spigot by elevating the barrel.Los Angeles Rainwater Harvesting Program 7
  • 11. Redirection Procedure Redirecting a downspout to a rain barrel is a relatively simple procedure. Elbow Step 1: Decide where to locate a rain barrel. The best place is either directly under or a few feet from the disconnected downspout. By attaching a hose to the spigot, a homeowner Measure Securing can transport water from the barrel to another strap area of the yard. Step 2: Estimate how high the barrel will rest under the downspout. Be sure to include the height of the cinder blocks or platform for the Wood / cinder blocks barrel. Mark where the downspout will be cut. Make sure to make your cut just high enough Steps 1-3 above the rain barrel to accommodate attach- ing an elbow. Hacksaw Tin snips Drill Step 3: Cut the downspout with a hacksaw so that the elbow will be inserted just above the rain barrel inlet. You may need tin snips to smooth the material. Needle-nose pliers Tape measure Step 4: Assemble the rain barrel platform. Make sure it is level. Sheet metal screws Screwdriver Step 5: Attach the elbow over the downspout with a screw. Secure the downspout to the house with the bracket. Level Safety glasses Step 6: Place the barrel beneath the elbow, making certain that the barrel overflow valve isFigure 5: Materials and tools needed for positioned in an appropriate location and awayinstalling a rain barrel from the home. Secure the barrel to the house Steps 4-6 with a strap. Los Angeles Rainwater Harvesting Program 8
  • 12. How to Build a Rain Garden Assess Potential Rain Garden Sites Locate.rain.gardens.where.they.can.intercept.Before you Begin and.collect.roof.runoff...Potential.rain.garden.Design.and.build.a.rain.garden.before.discon- sites.are.down.slope.of.a.downspout,.or.adja-necting.a.downspout...Helpful.video.instruc- cent.to.an.impervious.surface...The.following.tions.for.installing.a.rain.garden.are.available. factors.must.be.considered.when.siting.a.rain.by.Metro.Blooms.at.www.metroblooms.org... garden:Remember,.the.removal.of.grass.to.build.a. •. Build.a.rain.garden.in.a.relatively.flat.area.rain.garden.will.likely.qualify.homeowners.for. •. Build.a.rain.garden.in.a.naturally.low.lying.the.LADWP.Residential.Drought.Residential. area.with.good.drainage.Landscape.Incentive.Program...Please.call.Dig. •. Remove.grass.or.paved.surfaces.to.create.Alert.at.(888).376-3314.to.obtain.an.application. space.for.a.rain.garden.package.before.building.a.rain.garden. •. Do.not.site.rain.gardens.underneath.the.The.construction.of.a.rain.garden.will.poten- canopy.of.existing.trees.tially.result.in.the.redistribution.of.soil.on.a. •. Do.not.site.rain.gardens.above.septic.. © 2009 Central Ohio Rain Garden Initiativeproperty...As.a.consequence,.underground. systems.utilities.are.a.concern...Before.digging,.call. A.rain.garden.in.bloom •. Do.not.site.a.rain.garden.where.potential.1-800-227-2600.to.acquire.the.location.of. overflow.will.run.onto.neighboring..potential.underground.utilities...Constructing. 1..Perform.a.simple.soils.infiltration.test.to. properties.a.rain.garden.may.be.an.issue.if.you.live.on.a. calculate.the.drainage.rate.of.the.potential. As.a.guideline,.site.the.edge.of.a.rain.garden: rain.garden.site.designated.landslide.or.hillside.area...Visit.the.Navigate.LA.website.for.a.hillside.area.map.or. •. At.least.3.feet.away.from.public.sidewalks; 2..Calculate.the.rainfall.that.will.run.off.the.the.Zone.Information.and.Map.Access.System. •. At.least.5.feet.away.from.property.lines; portion.of.the.roof.that.will.be.directed.to.(Z1.MAS).websites.for.area.maps.(See.Addi- •. At.least.5.feet.away.from.house.foundations,. the.rain.garden.tional.Resources)...Permits.are.not.required.for. assuring.at.least.a.2%.slope.away.from.the. 3..Use.the.example.calculations.to.estimate.the.typical.residential.landscaping.projects...If.you. home. size.of.your.rain.garden.plan.on.making.major.landscaping.modifica- Design The rain garden sizing methodology is helpfultions.such.as.moving.more.than.50.cubic.yards. Size your garden:.It.is.easy.to.size.a.rain.garden. for maximizing the volume of runoff capturedof.soil.or.altering.1.acre.or.more,.contact.the. to.capture.a.common.3/4”.storm.event.... from a typical storm event. However, rain gar-Los.Angeles.Building.and.Safety.Department.at. There.are.three.key.elements.which.are.dis- dens smaller than the calculated size, or with(866).452-2489.for.further.assistance. cussed.in.depth.on.the.next.page: slow infiltration, can also make a difference.. Los.Angeles.Rainwater.Harvesting.Program 9
  • 13. Remember,.you.should.always.incorporate. Calculate Runoff and Rain Garden Size Direct water flowan.overflow.in.your.rain.garden.such.that.any. Step 4:.Estimate.the.total.roof.area.(RA).that. A.splash.guard,.followed.by.a.grassed.channel.excess.water,.from.larger.storm.events,.will. will.drain.to.your.potential.rain.garden...Note. or.swale,.directs.water.from.the.end.of.a.down-flow.into.another.infiltration.area,.or.to.the. that.rooftop.runoff.from.multiple.downspouts. spout.extension.to.the.rain.garden.site.(Page.storm.drain.system.and.away.from.the.home’s. can.be.used.to.support.one.rain.garden... 3)...Make.sure.that.the.swale.is.lined.with.an.foundation.or.neighboring.property. [RA = ___ (square feet)] impermeable.material,.such.as.a.geotextile,.if.it. located.in.the.vicinity.of.buildings...To.prevent.Perform a Soils Infiltration Test Step 5:.Multiply.the.roof.area.by.a.factor.of. 0.65.to.determine.the.volume.of.rooftop.runoff. erosion.and.create.a.dry.creek.bed.look,.add.The.following.is.a.list.of.tools.and.materials.you. that.will.flow.to.your.rain.garden.. different.sized.river.rocks.to.the.swale...When.will.need.to.conduct.a.soils.test: [V = RA x 0.65 = ___ (gallons)] the.rain.garden.is.filled.with.water.and.begins.•. Measuring.tape to.overflow,.direct.excess.water.flows.away.•. Garden.spade Step 6:.Plug.the.numbers.into.the.equation. from.buildings.and.neighboring.properties.•. Empty.gallon.container below.to.determine.the.required.size.of.the.rain.•. A.watch garden...If.the.calculated.rain.garden.size.is.too. Choose your plantsStep 1:.Dig.a.square.hole.two.feet.deep.and. big.for.the.property,.improve.drainage.by.the. There.are.a.variety.of.plants.that.can.be.used.one.foot.wide.in.the.deepest.section.of.the. tilling.method.and.recalculate.the.rain.garden. in.a.rain.garden...Diversity.in.plant.selection.potential.rain.garden...This.size.works.best.for. size...Smaller.gardens.can.be.installed.with.an. will.add.an.aesthetic.quality.to.your.garden..the.equation.provided.in.this.“How-To”.Guide. overflow..[(hours) x (gallons) x 0.008 = _____ Consider.native.and.drought.tolerant.species. square footage area of rain garden] that.adjust.well.to.seasonal.rainfall.patterns,.Step 2:.Fill.the.hole.with.water.and.let.it.drain. and.require.minimal.supplemental.irrigation...If.completely...Fill.the.hole.again.with.5.gallons.of. a.rain.barrel.is.installed,.the.captured.water.can.water.and.monitor.how.fast.the.water.drains... be.used.for.watering.plants...Record.how.many.hours.it.takes.to.drain.the.hole....[T = ____ (hours)] There.are.several.resources.available.for.the. Example: selection.of.rain.garden.plants.native.to.South-Step 3:.Consider.digging.more.holes.in.the.po- ern.California...Native.plant.nursery.profession-tential.rain.garden.site.to.determine.if.drainage. Optimal.Area.of.Rain.Garden:. als.or.garden.clubs.can.provide.assistance...The.is.uniform....If.drainage.is.too.slow.to.measure,. T.x.V.x.0.008.=.26.(square.feet) Rancho.Santa.Ana.Botanic.Gardens.provides.improve.the.drainage.by.tilling.in.a.mixture.of. native.plant.palette.lists.and.offers.native.plant. Where,.two-thirds.sandy.loam.topsoil.and.one-third. gardening.workshops...Please.visit.their.web- T.=.10.(hours).compost.to.a.depth.of.18.inches.. site.at.www.rsabg.org...Other.groups.include. RA.=.500.(square.feet). V.=.RA.x.0.65.=.325.(gallons) the.Water.Conservation.Garden.at.Cuyamaca. College,.the.California.Native.Plant.Society,. Los.Angeles.Rainwater.Harvesting.Program 10
  • 14. The.Garden.Spot.(bewaterwise),.The.Los.Angeles.and.San.Gabriel.Rivers. where.with.brilliant.orange.flowers...Attracts.Watershed.Council,.the.Surfrider.Foundation.Ocean.Friendly.Gardens,. butterflies.and.birds.and.the.Green.Garden.Group.(G3)...See.the.Additional.Resources.section. Deer Grass.–.Grass..Likes.full.sun.and.dry.to.for.more.information. semi-dry.soil...Mixes.well.with.wildflowers...Avoid.using.invasive.plant.species.in.your.rain.garden...Lists.of.invasive. Source.of.nesting.materials.for.birds.species.can.be.found.at.the.California.Invasive.Plant.Council,.Southern. © 2009 Ken Gillard Coyote Bush.–.Shrub...Likes.full.sun.and.dry.California.region.website:..www.cal-ipc.org....Some.trees.are.protected. California Poppy soils...Hardy.and.fast.growing...Attracts.birds.by.the.City.and.require.a.special.permit.for.removal...These.include:.all. and.butterflies.native.Oak.species,.Black.Walnut,.California.Bay,.and.California.Syca-more...Contact.the.Los.Angeles.Department.of.Public.Works.Bureau. Elegant Clarkia.–.Wildflower..Likes.sun.and.dry.of.Street.Services.Urban.Forestry.Division.at.(213).847-3077.for.more. to.semi-dry.soils...Easy.to.grow.and.long-lasting.information. showy.flowers.in.pink,.red.or.purple..Attracts. © 2009 Ken Gillard hummingbirds.and.butterflies.Plants for Southern CaliforniaA.few.of.the.many.plants.available.to.you.are.described.below...Photog- Deer Grass Purple Needle Grass –.Grass..Likes.sun.to.raphy.is.courtesy.of.Ken.Gillard.from.the.Theodore.Payne.Foundation. partial.sun.and.semi-dry.soils..Hardy.and.showy.www.theodorepayne.org with.purple.seed.heads..Attracts.songbirds. Bush Anemone.–.Shrub...Likes.full.sun.and.well. Rose Sage –Shrub...Likes.sun.to.partial.sun.and. drained.soil...Does.best.with.minimum.care... dry.soil..Compact.and.scented.with.rose.and. Produces.white.flowers.with.yellow.center.in. blue.colored.flowers...Attracts.hummingbirds,. the.spring...Attracts.butterflies.and.birds. songbirds,.butterflies,.bees.and.lizards. © 2009 Ken Gillard © 2009 Ken Gillard California Buckwheat.–.Groundcover...Likes.sun. Rose Sage White Sage.–.Shrub..Likes.sun.to.partial.sun.and. to.partial.sun.and.dry.to.semi-dry.soils..Hardy. dry.soils...Flower.stalks.are.long.and.arching.California Buckwheat and.shrubby.with.tiny.pink.and.white.flowers... with.white.flowers...Attracts.butterflies,.bees,. Attracts.butterflies,.bees.and.birds.. birds,.lizards.and.nectar-loving.insects. California Lilac “Concha”.-.Shrub..Fragrant.with. Woolly Blue Curls.–.Shrub..Likes.sun.to.partial. bright.blue.flowers..Likes.semi-dry.soil,.grows.to. sun.and.dry.soils...Native.to.Santa.Monica. be.6-8’.tall...Attracts.hummingbirds. Mountains.and.requires.no.water.in.the.sum- mer..Blue.and.pink.woolly.flowers.bloom.in. © 2009 Ken Gillard California Poppy.–.Annual.Wildflower...Likes.full. © 2009 Ken Gillard the.spring.and.fall...Attracts.hummingbirds.and.California Lilac - “Concha” sun.and.dry.to.semi-dry.soils...Thrives.every- butterflies. Woolly Blue Curls Los.Angeles.Rainwater.Harvesting.Program 11
  • 15. Build a Garden Use.the.following.steps.as.a.guide.for.building.a. rain.garden: Step 1:..Outline.the.rain.garden.area.with.string. and.stakes. Step 2: If.the.soil.is.too.hard.to.dig,.moisten.it. with.a.garden.hose...Allow.the.water.to.seep.in. overnight...Dig.up.existing.grass.and.plants...Set. aside.any.native.plants.that.can.be.used.in.the. garden. Step 3: Dig.the.rain.garden.18.inches.deep.. Frame.the.rain.garden.with.the.sides.sloped.Steps.1-2 to.about.20%...To.minimize.the.risk.of.erosion,. consider.lining.the.side.slopes.with.stones.or. plant.vegetation...If.the.rain.garden.is.on.a. slight.slope,.add.a.berm.on.the.downhill.slope. Step.4 to.hold.in.rainwater. Step 4: .Plant.the.rain.garden...Use.a.variety.of. species...After.planting,.add.compost.to.provide. nutrients.to.the.plants...Compost.or.soil.amend- ments.can.be.purchased.at.most.garden.supply. stores...The.City.of.Los.Angeles.also.offers.free. compost.at.the.Griffith.Park.Composting.Facil- ity...See.Additional.Resources.for.more.informa- tion.Step.3 Los.Angeles.Rainwater.Harvesting.Program 12
  • 16. Other Rainwater Harvesting Options In.addition.to.rain.barrels.and.rain.gardens,. infiltrate.runoff...Terraced.infiltration.basins.can. additional.rain.water.harvesting.features.can. be.formed.on.sloped.properties.. be.installed.at.a.residential.property..Visit.local. Impervious.walkways.and.driveways.can.be. demonstration.gardens,.take.a.workshop,.and. removed.and.replaced.with.permeable.paving. review.references.provided.in.the.Additional. such.as.“pavers”...Pavers.are.brick-like.materials. Resources.section.of.this.“How-To”.Guide.to. that.are.manufactured.in.a.variety.of.shapes... gather.ideas...Consider.consulting.a.contractor. Pavers.fit.together.like.tiles.and.are.set.with. or.a.landscape.designer.to.address.site.specific. small.gaps.between.them.creating.grooves.for. needs...Some.noteworthy.rainwater.harvesting. water.to.infiltrate.the.soil.below...Other.materi- applications.include.installation.of.dry.wells. als.such.as.broken.pieces.of.recycled.concrete. (also.known.as.French.drains).or.infiltration. can.also.be.used...Paved.walkways.can.also.be. basins,.and.replacing.paved.surfaces.with. removed.and.replaced.with.gravel.or.mulch. permeable.paving... Specifications.for.infiltration.projects.provided. A.dry.well.is.a.trench.or.basin.completely.filled. by.the.Los.Angeles.Department.of.Building.and. with.coarse.media,.such.as.angular.gravel,.to. Safety.and.the.Bureau.of.Sanitation.Watershed. create.a.porous.layer.for.infiltrating.runoff...Dry. Protection.Division.can.be.used.as.guidelines.. wells.are.suitable.for.foot-traffic,.and.are.typi- (See.Additional.Resources) cally.placed.between.a.driveway.or.patio.and.a. vegetated.area,.where.runoff.from.the.paved. surfaces.is.used.to.soak.deep.into.the.roots.of. adjacent.plants...Dry.wells.are.not.suitable.for. areas.that.would.generate.sediment.or.silt- laden.runoff. A.rain.garden.is.a.type.of.infiltration.basin... There.are.several.additional.infiltration.basin. designs.that.can.accommodate.existing.con- tours.and.vegetation.on.your.property...For. instance.depressions.extending.beyond.the. canopy.of.a.tree.can.be.created.to.catch.and.Los.Angeles.Rainwater.Harvesting.Program 13
  • 17. Rainwater Harvesting System Maintenance Perform.the.following.activities.to.maintain. your.rainwater.harvesting.system: Rain Gutters •. Clean.gutters.at.least.twice.a.year,.and.more. •. Check.and.clear.downspout.elbows,.rain. often.if.you.have.overhanging.trees. barrel.screening,.and.overflow.to.prevent. •. Make.sure.gutters.are.pitched.to.direct.water. clogging. to.downspouts. •. Repair.any.leaks.and.holes. •. Repair.leaks.and.holes. •. Make.sure.the.rain.barrel.remains.securely. •. Look.for.low.spots.or.sagging.areas.along.the. screened.to.prevent.mosquito.entry. gutter.line,.and.repair.with.spikes.or.place. •. Inspect.overflow.area.to.make.sure.that. new.hangers.as.needed. water.will.continue.to.drain.away.from. Downspouts structures.and.does.not.flow.onto.pavement,. •. Check.and.clear.elbows.or.bends.in.down- sidewalks.or.neighboring.properties.. spouts.to.prevent.clogging. Rain Gardens (or other landscaping) •. Repair.any.leaks.and.holes. •. Irrigate.deeply.once.a.week.during.dry. •. Each.elbow.or.section.of.the.downspout. months.to.encourage.root.growth.and.keep. should.funnel.into.the.one.below.it..All.parts. plants.strong,.especially.while.plants.are. should.be.securely.fastened.together.with. getting.established. sheet.metal.screws. •. Maintain.the.garden.regularly. Rain Barrels •. Inspect.your.garden.after.a.heavy.rain... •. Make.sure.all.parts.are.securely.fastened. Remove.sediment.and.debris,.watch.for.ero- together.and.the.rain.barrel.is.securely. sion,.and.replace.plants.as.needed. fastened.to.the.building. •. If.a.plant.isn’t.surviving.in.one.area,.try.mov- •. Clean.out.the.rain.barrel.and.check.for.leaks. ing.it.to.another. at.least.once.a.year...Los.Angeles.Rainwater.Harvesting.Program 14
  • 18. Where Can I Get More Information? The.Garden.Spot:.. http://www.bewaterwise.com/knowledge01.htmlHelp.can.be.acquired.from.several.sources...Start.with.the.City.of..Los.Angeles.Rainwater.Harvesting.Program..Explore.other.resources. Green.Garden.Group.(G3)including.local.organizations.that.provide.help.and.information.about. http://www.greengardensgroup.com/rain.gardens.and.the.use.of.native.plants. City.of.Los.Angeles.Department.of.City.Planning.Zone.Information.. &.Map.Access.System.(ZIMAS).The City of Los Angeles http://zimas.lacity.org/The.City.of.Los.Angeles.Rainwater.Harvesting.Pilot.Program..www.LARainwaterHarvesting.org Los.Angeles.County.Department.of.Public.Works,.Water.Conservation http://dpw.lacounty.gov/wwd/web/conserve.cfmThe.City.of.Los.Angeles.Standard.Urban.Stormwater.Mitigation.Plan.http://www.lacity.org/SAN/wpd/siteorg/businesses/susmp/ The.Los.Angeles.and.San.Gabriel.River.Watershed.Councilsusmpintro.htm http://lasgrwc2.org/Default.aspxThe.City.of.Los.Angeles.Griffith.Park.Composting.Facility. Metro.Blooms.(Rain.garden.installation.video.and.information)5400.Griffith.Park.Drive. http://metroblooms.org/index.phpLos.Angeles,.CA.90027. Metropolitan.Water.District.of.Southern.California.and.The.Family.of.(323).913-4166. Southern.California.Water.Agencies.www.lacity.org/san/srecd http://bewaterwise.comAdditional Resources Rancho.Santa.Ana.Botanic.Gardens:.California’s.Native.GardenCalifornia.Department.of.Water.Resources:. http://www.rsabg.orgA.Guide.to.Estimating.Irrigation.Water.Needs.of.Landscape.Planting.in. The.Surfrider.Foundation.Ocean.Friendly.Gardens.California..August.2000.. http://www.surfrider.org/ofg.asphttp://www.owue.water.ca.gov/docs/wucols00.pdf The.Theodore.Payne.Foundation.for.Wildflowers.and.Native.Plants,.Inc.California.Invasive.Plant.Council. http://www.theodorepayne.org/http://www.cal-ipc.org/ TreePeople.California.Native.Plant.Society:.. http://www.treepeople.org/Native.Plant.Nurseries.and.Local.Botanic.Gardens.http://lasmmcnps.org/nativenurseries.html The.Water.Conservation.Garden.at.Cuyamaca.College. http://www.thegarden.org/ Los.Angeles.Rainwater.Harvesting.Program 15
  • 19. PublicationsLancaster,.Brad...Rainwater.Harvesting.for.Drylands.and.Beyond:.Volume.2.Water-Harvesting.Earthworks...Rainsource.Press..2008..ISBN.978-0-9772464-1-0Los.Angeles.Waterworks.District.No..29..Drought.Tolerant.Plantshttp://dpw.lacounty.gov/wwd/web/booklet/docs/Drought%20Toler- © 2009 G3LAant%20Plants.pdfThe.City.of.Los.Angeles.Department.of.Building.and.Safety.Information. Glossary of TermsBulletin/.Public..-.Building.Code:.Guidelines.for.Stormwater.Infiltration... Berm – A.mound.of.earth.used.to.retain.water,.such.as.along.the.down-Document.No..P/BC.2008-118...Effective.01/01/2008. slope.side.of.a.rain.gardenhttp://www.ladbs.org/faq/info%20bulletins/building%20code/2008/IB-P-BC%202008-118%20Stormwater%20Infiltn.pdf Downspout –.Pipe.that.directs.stormwater.runoff.from.the.roof.of.a. house.to.the.ground..The.City.of.Los.Angeles.Department.of.Public.Works.Bureau.of..Engineering:.Hillside.Areas.Map. Impervious – Not.allowing.water.to.penetrate...Examples.of.impervious.http://navigatela.lacity.org/common/mapgallery/pdf/hillsidearea.pdf surfaces.include.paved.driveways,.walkways,.or.roofs.The.City.of.Los.Angeles.Standard.Urban.Stormwater.Mitigation.Plan:. Pervious – Allowing.water.to.penetrate...Examples.of.pervious.surfaces.Infiltration.Requirements.and.Guidelines. include.flower.beds.and.rain.gardens.http://www.lastormwater.org/Siteorg/download/pdfs/tech_docs/ Rain Garden -A.planted.depression.that.allows.rainwater.runoff.from.SUSMP_Infiltration_Req.pdf impervious.urban.areas.like.roofs,.driveways,.walkways.and.compacted.Metropolitan.Water.District.of.Southern.California..Plants.for.Southern. lawn.areas.to.be.absorbed.into.the.earth.California.Homes. Rain gutter –.Captures.and.redirects.stormwater.runoff.from.the.roof.to.http://www.ci.glendora.ca.us/Modules/ShowDocument. a.downspout..(Figure.3)aspx?documentid=1839 Runoff – Water.that.does.not.soak.into.the.ground.and.flows.over.im-Metropolitan.Water.District.of.Southern.California.and.The.Family.of. pervious.areas.or.areas.already.saturated.with.water...In.the.City.of.Los.Southern.California.Water.Agencies..California.Friendly.Garden.Easy. Angeles.runoff.from.storm.events flows.into.the.ocean.without.being.Update.Weekend.Project:.Mulch.your.plant.beds. treated..http://www.bewaterwise.com/pdf_weekendMulch.pdf Swale – A.shallow.ditch,.usually.lined.with.river.cobble.or.vegetation.to. prevent.erosion,.which.conveys.runoff.to.a.certain.location,.such.as.a. rain.garden. Los.Angeles.Rainwater.Harvesting.Program 16
  • 20. www.LARainwaterHarvesting.org Program funded by the Safe Neighborhood Parks, Clean Water, Clean Air and Coastal Protection BondAct of 2000 (Prop 12) through the Santa Monica Bay Restoration Commission and the California Coastal Conservancy City of Los Angeles • Department of Public Works • Bureau of Sanitation • Watershed Protection Program As a covered entity under Title II of the Americans with Disabilities Act, the City of Los Angeles does not discriminate on the basis of disability and upon request, will provide reasonable accommodation to ensure equal access to its programs, services and activities.