rain gardens landscaping for water quality presented by the soil and water conservation district of...

Rain GardensRain GardensLandscaping for water qualityLandscaping for water quality

Presented by the Soil and Water Conservation District Presented by the Soil and Water Conservation District of Lake Countyof Lake County

What is a rain garden?What is a rain garden?

A rain garden is a shallow depression A rain garden is a shallow depression in your yard that is planted with in your yard that is planted with native flowers and grassesnative flowers and grasses

It is positioned in the yard to receive It is positioned in the yard to receive runoff from your roof, sidewalks, runoff from your roof, sidewalks, driveway and lawns allowing water to driveway and lawns allowing water to slowly soak into the groundslowly soak into the ground

Rain gardens – a short Rain gardens – a short historyhistory

Rain gardens are a relatively new conceptRain gardens are a relatively new concept They emerged in 1993 in Maryland out of the need They emerged in 1993 in Maryland out of the need

for low cost stormwater infiltration methods that for low cost stormwater infiltration methods that would improve water qualitywould improve water quality

The idea of bioretention or holding and filtering The idea of bioretention or holding and filtering stormwater in plant systems came aboutstormwater in plant systems came about

The term was later refined as rain gardens as it was The term was later refined as rain gardens as it was more attractivemore attractive

Since then, the concept of rain gardens has been Since then, the concept of rain gardens has been developed by other states especially Minnesota, developed by other states especially Minnesota, Michigan and Wisconsin Michigan and Wisconsin

A more widespread use of such gardens could A more widespread use of such gardens could dramatically improve water quality everywheredramatically improve water quality everywhere

Why are they important?Why are they important? The conversion of land from forests, The conversion of land from forests,

grassland and agricultural land to grassland and agricultural land to urban and suburban lots has urban and suburban lots has reduced the natural ability rain water reduced the natural ability rain water to infiltrate into the ground because to infiltrate into the ground because of increased impervious surfacesof increased impervious surfaces

This results in stormwater runoff that This results in stormwater runoff that carries pollutants from streets, carries pollutants from streets, parking lots and lawns into our local parking lots and lawns into our local lakes and streams, degrading their lakes and streams, degrading their water qualitywater quality

Why are they important?Why are they important?

Chicago (1970-1990)…Chicago (1970-1990)…

288,000 acres converted288,000 acres converted35% increase in 35% increase in

developed land developed land 4 % increase in 4 % increase in

population population

Urban areas are spreading rapidly...Urban areas are spreading rapidly...

Green Infrastructure: A Strategic Approach to Natural Resource Planning and Conservation

Why are they important?Why are they important?

One way we can improve water One way we can improve water quality right on our own properties, quality right on our own properties, is by planting rain gardens, that can is by planting rain gardens, that can filter and re-direct rain waterfilter and re-direct rain water

Even though they are small in size, Even though they are small in size, collectively they can make a big collectively they can make a big differencedifference

Rain Garden BasicsRain Garden Basics LocationLocation

Your rain garden should be at least 10 feet Your rain garden should be at least 10 feet away from your houseaway from your house

It can be placed close to your downspout so it It can be placed close to your downspout so it only receives water from the roofonly receives water from the roof

Or further away so it catches water from your Or further away so it catches water from your roof and your lawn roof and your lawn

Don’t put it where water already ponds – the Don’t put it where water already ponds – the idea is to encourage infiltrationidea is to encourage infiltration

Plants will grow easier in full sun than in shade Plants will grow easier in full sun than in shade or under a treeor under a tree

A flat area of the yard will be easier to dig than A flat area of the yard will be easier to dig than on a slopeon a slope

LocationLocation

Picture courtesy of Wisconsin DNR

Rain Garden BasicsRain Garden Basics SizeSize

You should choose a garden size that you You should choose a garden size that you can manage; typical sizes are between can manage; typical sizes are between 100 and 300 sq.ft.100 and 300 sq.ft.

The depth can vary between 4 and 8 The depth can vary between 4 and 8 inchesinches

A garden that is too small and too shallow A garden that is too small and too shallow will not have enough plant variety and will not have enough plant variety and will not provide appropriate infiltrationwill not provide appropriate infiltration

Similarly a garden that is too large and Similarly a garden that is too large and too deep will be hard to maintain, too deep will be hard to maintain, expensive and will resemble a hole in the expensive and will resemble a hole in the ground filled with waterground filled with water

Rain Garden BasicsRain Garden Basics SizeSize

To find the perfect size for your garden To find the perfect size for your garden take into considerations a few things:take into considerations a few things:

Soil typesSoil types Drainage area that will feed into the gardenDrainage area that will feed into the garden Depth of gardenDepth of garden

Clayey soils drain slower that sandy and Clayey soils drain slower that sandy and silty silty

The bigger the drain area, the bigger the The bigger the drain area, the bigger the garden should begarden should be

Depth of garden should be determined Depth of garden should be determined by the slope of the lawnby the slope of the lawn

Rain Garden BasicsRain Garden Basics Determine soil typeDetermine soil type

The soaking testThe soaking test The ribbon testThe ribbon test

Determine the drainage area of your Determine the drainage area of your propertyproperty

For gardens less than 30 feet from downspoutFor gardens less than 30 feet from downspout For gardens more than 30 feet from downspoutFor gardens more than 30 feet from downspout

Determine the depth of the rain garden Determine the depth of the rain garden by determining the slope of the lawnby determining the slope of the lawn

Determining slopeDetermining slope


Rain Garden SizeRain Garden Size Having determined soil types, drainage area and depth, Having determined soil types, drainage area and depth,

you can now calculate the surface area of your gardenyou can now calculate the surface area of your garden Use the table below to do thatUse the table below to do that

1.1. Find the size factor for the soil type and rain garden Find the size factor for the soil type and rain garden depth.depth.

2.2. Multiply the size factor by the drainage area. This Multiply the size factor by the drainage area. This number is the recommended rain garden area.number is the recommended rain garden area.

3.3. If the recommended rain garden area is much more If the recommended rain garden area is much more than 300 square feet, divide it into smaller rain than 300 square feet, divide it into smaller rain gardens.gardens.

Building Your GardenBuilding Your Garden

Anytime before digging in your Anytime before digging in your garden you should call JULIE (Joint garden you should call JULIE (Joint Utility Locating Information for Utility Locating Information for Excavators) at Excavators) at 1 800 892-01231 800 892-0123

Recruit some friends to help you out Recruit some friends to help you out so the work will take less timeso the work will take less time

Do some advanced prep work to Do some advanced prep work to lighten up the physical loadlighten up the physical load

Building Your GardenBuilding Your Garden Start out by defining the shape of the garden Start out by defining the shape of the garden

with a string or a flexible hosewith a string or a flexible hose While you dig put the soil outside of the string; While you dig put the soil outside of the string;

you will use the displaced soil to build a berm you will use the displaced soil to build a berm or a low wallor a low wall

If you are on an incline start out at the high If you are on an incline start out at the high end and work your way towards the low end; end and work your way towards the low end; make sure you know how deep your garden make sure you know how deep your garden has to behas to be

When you are done digging check to see that When you are done digging check to see that the bottom of your garden is flat; you can the bottom of your garden is flat; you can “eyeball it” or use a 2x4 and a carpenter’s “eyeball it” or use a 2x4 and a carpenter’s levellevel

Building Your GardenBuilding Your GardenPicture courtesy of Wisconsin DNR


If your lawn has a slope greater then 8% If your lawn has a slope greater then 8% you will need to use some of the soil you you will need to use some of the soil you dig to level the gardendig to level the garden

The rest of the soil will be used to build the The rest of the soil will be used to build the bermberm

When you are done digging, rake the soil When you are done digging, rake the soil smooth and prepare for plantingsmooth and prepare for planting

For better plant establishment compost For better plant establishment compost can be used; you can mix it with your soilcan be used; you can mix it with your soil

Building Your GardenBuilding Your GardenPicture courtesy of Wisconsin DNR

Choosing plantsChoosing plants You should choose plants based on You should choose plants based on

the sun/shade pattern and soil type the sun/shade pattern and soil type to ensure proper growth to ensure proper growth

Native plants is they way to go due Native plants is they way to go due to their resilience and low to their resilience and low maintenance needsmaintenance needs

They come in different varieties and They come in different varieties and colors, they are drought resistant colors, they are drought resistant and they don’t require fertilizer and and they don’t require fertilizer and pesticidespesticides

Picture Courtesy of Chicago Wilderness

Root system of the prairie grassesRoot system of the prairie grasses

Plants for full sunPlants for full sun

Plants for partial shadePlants for partial shade

Plants for shady areasPlants for shady areas

PlantingPlanting You should come up with a pleasing You should come up with a pleasing

design keeping in mind the height of design keeping in mind the height of the plants and color variationthe plants and color variation

Clump plants together for a visually Clump plants together for a visually enjoying displayenjoying display

Do not exclude the rest of your Do not exclude the rest of your property – plan the rain garden as part property – plan the rain garden as part of a wholeof a whole

Native plants should be planted about Native plants should be planted about 1 foot apart to allow roots to grow well 1 foot apart to allow roots to grow well

As soon as you finish mulch and waterAs soon as you finish mulch and water

MaintenanceMaintenance The first year after planting your rain garden is The first year after planting your rain garden is

very important in terms of maintenancevery important in terms of maintenance It will determine how well your garden will do It will determine how well your garden will do

in the futurein the future Two key components are watering and Two key components are watering and

weedingweeding Second component cannot be emphasized Second component cannot be emphasized

enough since the plants and weeds are in enough since the plants and weeds are in powerful competition for resourcespowerful competition for resources

Once the garden is established (typically it Once the garden is established (typically it takes 2-3 years for complete establishment) takes 2-3 years for complete establishment) the amount of maintenance will reduce the amount of maintenance will reduce considerablyconsiderably

Alternative to Rain GardensAlternative to Rain Gardens

If you feel that installing a rain If you feel that installing a rain garden is too much work, you can garden is too much work, you can take advantage of rain barrelstake advantage of rain barrels

They collect rain water from your They collect rain water from your roofs, which can be used for roofs, which can be used for irrigation laterirrigation later

It is a cheap, easy alternative and It is a cheap, easy alternative and requires no maintenancerequires no maintenance

Rain BarrelsRain Barrels

Residential irrigation can account for Residential irrigation can account for 40% of domestic water consumption 40% of domestic water consumption in a given municipalityin a given municipality

Rain barrels not only store water, they Rain barrels not only store water, they help decrease demand during the help decrease demand during the times when precipitation is scarcetimes when precipitation is scarce

Only 1/4 inch of rainfall runoff from Only 1/4 inch of rainfall runoff from the average roof will completely fill the average roof will completely fill the typical barrel the typical barrel


Rain water is ideal for watering Rain water is ideal for watering your gardens because it tends to your gardens because it tends to have fewer sediments and have fewer sediments and dissolved salts than municipal dissolved salts than municipal waterwater

Saving water in this manner will Saving water in this manner will reduce your demand for treated reduce your demand for treated tap water, and save money by tap water, and save money by lowering your monthly bill lowering your monthly bill


Picture Courtesy of www.rainbarrelguide.com

ResourcesResources

One of the best resources is the One of the best resources is the booklet I used for this presentation booklet I used for this presentation “Rain Gardens – A How To Manual For “Rain Gardens – A How To Manual For HomeownersHomeowners

The Soil and Water Conservation The Soil and Water Conservation District of Lake County can help District of Lake County can help answering any questions about native answering any questions about native plantsplants

Also Applied Ecological Services can Also Applied Ecological Services can help with designs and planting ideashelp with designs and planting ideas

Rain gardensRain gardens

Questions ???Questions ???

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