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Santa Monica CA Rainwater Harvesting Manual
 

Santa Monica CA Rainwater Harvesting Manual

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Rainwater Harvesting Manual

Rainwater Harvesting Manual

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    Santa Monica CA Rainwater Harvesting Manual Santa Monica CA Rainwater Harvesting Manual Document Transcript

    • City of Culver City Rainwater Harvesting ProgramTable of ContentsIntroduction .....................................................................................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 .............................................................10Why Harvest Rainwater? ..................................................................2 Calculate Runoff and Rain Garden Size..................................................10To Protect Our Bays and Ocean .............................................................2 Direct Water Flow..................................................................................10To Reduce Energy Demands ..................................................................2 Choose your Plants ................................................................................10To Practice Water Conservation ............................................................2 Plants for Southern California ...............................................................11To Recharge Groundwater Supplies.......................................................2 Build your Garden .................................................................................12Overview of Rainwater Harvesting ...................................................2 Other Rainwater Harvesting Options ................................................13Redirection Options...............................................................................2 Rainwater Harvesting System Maintenance ......................................14What is a Rain Barrel? ...........................................................................2 Rain Gutters ........................................................................................... 14What is a Rain Garden? .........................................................................3 Downspouts .......................................................................................... 14How to Harvest Rainwater on Your Own ...........................................4 Rain Barrels ........................................................................................... 14Assess your Site .....................................................................................4 Rain Gardens ......................................................................................... 14Redirection Criteria Checklist and Safety Considerations ......................4 Where Can I Get More Information? .................................................15How to Measure a Slope .......................................................................4 The City of Culver City ...........................................................................15How to Redirect a Downspout to a Pervious Area .............................5 Additional Resources .............................................................................15Before you Begin ...................................................................................5 Glossary of Terms ..................................................................................15Redirection Procedure ...........................................................................6How to Redirect a Downspout to a Rain Barrel .................................7Before you Begin ...................................................................................7Redirection Procedure ...........................................................................8How to Build a Rain Garden ..............................................................9 Rainwater Harvesting Program i
    • Introduction impervious surface such as a sidewalk, driveway or parking lot.Background Rainwater harvesting is the process of inter-The City of Culver City 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 whiletheir roofs into the storm drain system. The simultaneously reducing the pressure on ourProgram 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 homeownersDue 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 theof 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 homeownerssoil 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 infiltraterapid 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 AdditionalMany residential and commercial properties Resources provided in this guide. The programin the City of Culver City are fitted with down- website (CCrainwater.ballonawatershed.org)spouts. When it rains, water runs off roofs, will be updated with useful information as well.through these downspouts and usually onto an1 Natural Resource Defense Council Technical Report. A ClearBlue Future: How Greening California Cities Can Address WaterResources and Climate Challenges in the 21st Century. August © 2009 G3LA2009. Rainwater Harvesting Program 1
    • 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’sa variety of pollutants. By capturing rainwater drinking water comes from groundwater.that falls on roofs, landowners help reduce the Harvesting rainwater and allowing it to infiltrateamount of runoff ultimately reaching the Santa into the ground replenishes our groundwaterMonica Bay, and thus aid in improving the qual- supplies.ity of our local surface waters. Overview of Rainwater HarvestingTo Reduce Energy Demands Redirection OptionsThe State of California Energy Commission The City suggests redirecting stormwater runoffreported that water-related energy consump- from downspouts to either a rain barrel or antion in California accounts for nearly 20% of the on-site pervious area such as a flower bed orState’s electricity, 30% of its natural gas, and rain garden as “first-steps” in the rainwaterrequires about 88 billion gallons of diesel fuel harvesting process. There are many moreevery 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 Rainwateramount of potable water with captured rain Harvesting Options and Additional Resourceswater, 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 forCalifornia has entered an era of increasing reuse in landscape irrigation. Rain barrelswater scarcity, coupled with projections of are containers typically made of a heavy dutyincreased temperatures up to 10 degrees plastic and can range in size from the standardFahrenheit by the end of this century.2 55 gallons to more than 80 gallons. Eco-friendly2 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. Rainwater Harvesting Program 2
    • Key components of a rain barrel include the • Rain barrels must be accessible for periodicfollowing: 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 CCrainwater.ballonawatershed.org (if desired). What is a Rain Garden?Rain barrels are typically placed below down-spouts and must meet the following require- Homeowners can maximize both environmen-ments: tal and economic benefits by installing a rain 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 cap- etration in order to prevent algae growth; tures rainwater and allows it to soak into the• Rain barrels must be covered and any open- ground. Plants help to filter harmful pollutants ings must be screened to prevent mosquito in the the rainwater as it moves through the soil breeding; and layer. A rain garden is most often planted with Downspout native species creating a natural ecosystem on properties where birds, butterflies, and benefi- Swale Overflow Screen Valve cial insects thrive. Rain gardens also capture sediments carried by rainwater, preventing them from clogging the stormdrains. Barrel Spigot Multi-barrel Connector A swale directs water from the downspout to the rain garden. Many swales use rocks thatA typical rain barrel set up create a dry creek bed look. Rainwater Harvesting Program 3
    • 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% slopedownspouts 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 thethese downspouts are candidates for discon- ground. Make certain that the string attachednection. 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 andIt 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 100spout 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 Rainwater Harvesting Program 4
    • 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 Culver City 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 Rainwater Harvesting Program 5
    • 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 Rainwater Harvesting Program 6
    • 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.Rainwater Harvesting Program 7
    • 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. Rainwater Harvesting Program 8
    • How to Build a Rain Garden Assess Potential Rain Garden Sites Locate rain gardens where they can interceptBefore you Begin and collect roof runoff. Potential rain gardenDesign 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 followingtions for installing a rain garden are available by factors must be considered when siting a rainMetro Blooms at www.metroblooms.org. The garden:construction of a rain garden will potentially • Build a rain garden in a relatively flat area.result in the redistribution of soil on a property. • Build a rain garden in a naturally low lyingAs a consequence, underground utilities are a area with good drainage.concern. Before digging, call 1-800-227-2600 to • Remove grass or paved surfaces to createacquire the location of potential underground space for a rain garden.utilities. If a project does require the redistribu- • Do not site rain gardens underneath thetion of soil it may be possible to contour the canopy of existing trees.dirt into berms or terraces designed to slow © 2009 Central Ohio Rain Garden Initiative • Do not site rain gardens above septicthe flow of water. Additionally, the formation systems.of shallow depressions on the upflow side of A rain garden in bloom • Do not site a rain garden where potentialthe berms may trap water altogether allowing overflow will run onto neighboringthe opportunity for it to infiltrate into the soil. 1. Perform a simple soils infiltration test to properties.Constructing a rain garden may be an issue if calculate the drainage rate of the potentialyou live on a designated landslide or hillside As a guideline, site the edge of a rain garden: rain garden site.area. Visit the Navigate LA website for a hillside • At least 3 feet away from public sidewalks; 2. Calculate the rainfall that will run off thearea map or the Zone Information and Map Ac- • At least 5 feet away from property lines; portion of the roof that will be directed tocess System (Z1 MAS) websites for area maps. • At least 5 feet away from house foundations, the rain garden.Permits are not required for typical residential assuring at least a 2% slope away from the 3. Use the example calculations to estimate thelandscaping projects. If you plan on making home. size of your rain garden.major landscaping modifications such as mov- Design The rain garden sizing methodology is helpfuling more than 50 cubic yards of soil or altering for maximizing the volume of runoff captured Size your garden: It is easy to size a rain garden1 acre or more, contact the Culver City Building from a typical storm event. However, rain gar- to capture a common 3/4” storm event.and Safety Department at (310) 253-5780 for dens smaller than the calculated size, or with There are three key elements which are dis-further assistance. slow infiltration, can also make a difference. cussed in depth on the next page: Rainwater Harvesting Program 9
    • 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 channelexcess 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 (Pagestorm 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 anfoundation or neighboring property. [RA = ___ (square feet)] impermeable material, such as a geotextile, if it located in the vicinity of buildings. To preventPerform 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, addThe following is a list of tools and materials you that will flow to your rain garden. different sized river rocks to the swale. Whenwill 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 usedone foot wide in the deepest section of the tilling method and recalculate the rain garden in a rain garden. Diversity in plant selectionpotential 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. Ifcompletely. Fill the hole again with 5 gallons of a rain barrel is installed, the captured water canwater and monitor how fast the water drains. be used for watering plants.Record how many hours it takes to drain thehole. [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. Theis uniform. If drainage is too slow to measure, T x V x 0.008 = 26 (square feet) Rancho Santa Ana Botanic Gardens providesimprove 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, The Rainwater Harvesting Program 10
    • Garden Spot (bewaterwise), the Surfrider Foundation Ocean Friendly where with brilliant orange flowers. AttractsGardens, and the Green Garden Group (G3). See the Additional Resourc- butterflies and birds.es section for more information. Deer Grass – Grass. Likes full sun and dry toAvoid using invasive plant species in your rain garden. Lists of invasive semi-dry soil. Mixes well with wildflowers.species can be found at the California Invasive Plant Council, Southern Source of nesting materials for birds.California region website: www.cal-ipc.org . Some trees are protected © 2009 Ken Gillard Coyote Bush – Shrub. Likes full sun and dryby the City and require a special permit for removal. These include: all California Poppy soils. Hardy and fast growing. Attracts birdsnative Oak species, Black Walnut, California Bay, and California Syca- and butterflies.more. Contact the Culver City Department of Public Works , at (310)253-5600 for more information. Elegant Clarkia – Wildflower. Likes sun and dry to semi-dry soils. Easy to grow and long-lastingPlants for Southern California showy flowers in pink, red or purple. AttractsA few of the many plants available to you are described below. Photog- hummingbirds and butterflies. © 2009 Ken Gillardraphy is courtesy of Michael Charters at www.calflora.net Deer Grass Purple Needle Grass – Grass. Likes sun to partial sun and semi-dry soils. Hardy and showy 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 White Sage – Shrub. Likes sun to partial sun and Rose Sage to partial sun and dry to semi-dry soils. Hardy dry soils. Flower stalks are long and archingBush Anemone 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 andCalifornia Buckwheat sun and dry to semi-dry soils. Thrives every- Woolly Blue Curls butterflies. Rainwater Harvesting Program 11
    • 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 slopedSteps 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 offers free compost at the Griffith Park Composting Facil- ity. Call (323) 913-4166 for further information.Step 3 Rainwater Harvesting Program 12
    • Other Rainwater Harvesting Options In addition to rain barrels and rain gardens, infiltrate runoff. Terraced infiltration basins can additional rainwater 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. Regardless which option you choose, the A dry well is a trench or basin completely filled primary goal of any rainwater harvesting strat- with coarse media, such as angular gravel, to egy is to redirect water into the ground or a create a porous layer for infiltrating runoff. Dry holding tank before it reaches the storm drains. wells are suitable for foot-traffic, and are typi- Imagine a property as a “mini-watershed”, the cally placed between a driveway or patio and a principal objective is to completely eliminate vegetated area, where runoff from the paved runoff from leaving the property boundaries. surfaces is used to soak deep into the roots of These strategies and ideas will assist in recharg- adjacent plants. Dry wells are not suitable for ing the groundwater in a drought ridden state areas that would generate sediment or silt- and filtering harmful pollutants from the water- laden runoff. ways. 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 andRainwater Harvesting Program 13
    • 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.Rainwater Harvesting Program 14
    • Where Can I Get More Information?Help can be acquired from several sources. Start with the City ofCulver City Rainwater Harvesting Program. Explore other resourcesincluding local organizations that provide help and information aboutrain gardens and the use of native plants.The City of Culver City Glossary of TermsThe City of Culver City Rainwater Harvesting Pilot Program Berm – A mound of earth used to retain water, such as along the down-CCrainwater.ballonawatershed.org slope side of a rain gardenrainwater@santamonicabay.org Downspout – Pipe that directs stormwater runoff from the roof of aCulver City Department of Public Works, Environmental Programs house to the ground.http://www.culvercity.org/Government/PublicWorks/Environmental-Programs.aspx Impervious – Not allowing water to penetrate. Examples of impervious surfaces include paved driveways, walkways, or roofs.Additional Resources Pervious – Allowing water to penetrate. Examples of pervious surfacesCalifornia Invasive Plant Council include flower beds and rain gardens.http://www.cal-ipc.org/ Rain Garden -A planted depression that allows rainwater runoff fromNative Plant Nurseries and Local Botanic Gardens impervious urban areas like roofs, driveways, walkways and compactedhttp://lasmmcnps.org/nativenurseries.html lawn areas to be absorbed into the earth.Green Garden Group (G3) Rain gutter – Captures and redirects stormwater runoff from the roof tohttp://www.greengardensgroup.com/ a downspout. (Figure 3)Metro Blooms (Rain garden installation video and information) Runoff – Water that does not soak into the ground and flows overhttp://metroblooms.org/index.php impervious areas or areas already saturated with water. In the City ofThe Surfrider Foundation Ocean Friendly Gardens Culver City runoff from storm events flows into the ocean without beinghttp://www.surfrider.org/ofg.asp treated.TreePeople Swale – A shallow ditch, usually lined with river cobble or vegetation tohttp://www.treepeople.org/ prevent erosion, which conveys runoff to a certain location, such as a Rainwater Harvesting Program 15