Partnership for Rain Gardens, LLC

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Rain Gardens Sustainable Stormwater Management
Produced by University of Wisconsin - Extension
Wisconsin Department of Natural Resources
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80 of Wisconsin residents drink well water
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Rain that falls here ...
soaks into the earth ...
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where it replenishes ournatural waterways.
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Headwaters for Token Creek, Madison
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Conservation Subdivision
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How do these homes, streets and businesses impact
the stream?
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Groundwater Drawdown Regions
Each line represents 10 to 50 feet of groundwater
drawdown
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Peoples wells are drying up
Dane County
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96
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Rain falls on our roadways,parking lots roofs
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Water emerges at a high velocity through storm
sewer systems and can create a host of problems.
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Baseflow
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Impacts of imperviousness

• 1) Reduces infiltration
• Diminished base flow
• Increased well failure
• Lose wetlands

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• 2) Increased flooding

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Projected Increase in Urban Runofffor Lake
Mendota(from 2000-2020)
Amounts of Urban Runoff for 2000
Amounts of Urban Runoff for 2020
5,600,000,000Gallons
8,800,000,000Gallons
An Increase of 57
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3) Erosion
Lincoln Creek, Milwaukee 2000
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Engineered Waterways
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The yellow dots represent the number of fish
species
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Not Just Quantity.

• Quality too!

Soil Manure Fertilizer
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And with each rain runoff, organic matter,
soil, fertilizer, oil and chemicals get added
to our lakes and streams.
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Six Mile Creek, Dane County
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Mason Lake, Adams County
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Excess plant growth effects our enjoyment of
our waterways.
Lake Wingra, Madison
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Water based tourism bringsWisconsin 12 to 15
billion dollars every year
Lake Mendota, Madison
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Our Goal
Act more like this
Need to make this
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Rain Gardens

• Sunken garden with native perennials
• 4-6 inches deep with flat bottom
• Normally 1/3 the size of area draining to it
• Formal or informal

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Value of Using Native Plants
Deeper roots absorbs more water Uses no
fertilizer Uses little or no pesticides Does
not require watering after establishment
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Do they work?
Three rain gardens infiltrate 60 of stormwater
St Francis subdivision, Cross Plains
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994 gallons - 90 infiltrated
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Benefits of Rain Gardens
Helps to protect restore natural hydrology
Allows rain to soak into the ground
Intercept pollutants
On a 2000 sq ft house with rain gardens at each
downspout, rain gardens can catch and infiltrate
32,000 gallons of water a year.
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Attractive Addition to
Property Enhance Beauty of City
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Building a Rain Garden
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Places to Use Rain Gardens

• Below roof downspouts

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Places to Use Rain Gardens
Boulevards
Even industrial sites can work!
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Deciding on the best spot to site your rain
garden
Your rain garden

• Should be at least ten feet from a foundation
• Integrate with your landscaping
• Sunny or partly sunny locations are best, but a
  shade garden is possible
• Should not be located where water ponds
• The flatter the site the better less than 12
  slope
• Do not locate over septic system

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How to Size a Rain Garden
Questions to ask yourself What type of soil
do I have? How big is the area draining to the
rain garden? What is the slope? What is the
best size to fit my yard? (smaller means deeper
to hold the same amount of water)
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Calculating Drainage Area

• Area of roof going
• to down spout

• Length of house 100 feet
• Width of house 20 feet
• L X W 2000 sq ft
• 2000 sq ft 4 500 sq ft draining to rain
  garden

Length
Width
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Determining Your Soil Type

• Some hints
• Soil feels gritty and coarse sandy
• Soil feels smooth not sticky silty
• Soil feels sticky and clumpy clayey
• Have soil analyzed
• Use perc test

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Importance of Soil Type

• The higher the infiltration rate the smaller
  the rain garden can be
• Infiltration Rate of Sandy Soils 2.5 in/hr
• Infiltration Rate of Silty Soils 0.5 in/hr
• Infiltration Rate of Clayey Soils 0.3 in/hr

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Determining Size of Drainage

• If less than 30 feet use Table 1
• If greater than 30 feet use Table 2

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Using Size Factor and Depth to Determine Final
Rain Garden Size with 100 Control
Less than 30 feet from downspout
More than 30 feet from downspout
Example 500 sq ft x .25 125 sq ft rain
garden Roof drain area x soil factor size of
rain garden
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From Start to Finish

• Roger Bannermans rain gardens

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CALL DIGGERS HOTLINE!!
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uphill
Down spout
uphill
berm
downhill
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Make sure the bottom of your rain garden is flat
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Add a weed barrier and mulch
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Cost of Rain Gardens

• If you do the work but purchase plants,cost
  is about 3 to 5 per square foot.
• Cost of landscape consultants in Wisconsin is
  about 10 to 15 per square foot.Includes
  design, construction, plants, and planting.
• A 300 square foot rain garden costsbetween
  1,000 and 4,500.

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Answering Neighbors Concerns

• Mosquitoes?
• There shouldnt be any if the garden is properly
  sited and designed. Rain gardens should drain in
  no more than five days.
• Mosquitoes have a 7 to 12 day life cycle from egg
  to adult.
• Mosquitoes that carry most diseases dont live in
  ponds. They prefer small amounts of standing
  water such as holes in trees, old tires or bird
  baths.

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Other Things to Consider

• Weed ordinances
• Check the web, most communities have them under
  nuisances
• Many communities use DNR noxious weed list
• Sample language for modifying weed ordinances at
  Wild Ones http//www.for-wild.org/weedlaws/weedla
  w.html

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Thank You!
For more information clean-water.uwex.edu/pubs
Produced by Suzanne Wade, Jennifer Erickson
University of Wisconsin-Extension Laura Lueders,
Kristi Minahan, Roger Bannerman Department of
Natural Resources Photo Credits Roger
Bannerman, Jim Bertolacini, Margaret Burlingham,
Center for Watershed Protection, DNR and UWEX
file photos, Matt Hanson, Carolyn Johnson,
Maplewood MN Public Works, Bob Queen, Ellen
Rulseh, Bill Volkert, Suzanne Wade, Larry
Coffman, Applied Ecological Services, Genesis
Bichanich, Barr Engineering, David Thompson
and Candy Schrank July 2007