Transcript Rain Water Management - University of Tennessee system

Water Quality Issues, Fees and
Management Options
Mr. L Sizemore and Dr. W. Anderson
Middle Tennessee State University for
the Mid-State Iris Association
June 3, 2008
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Why a Storm Water Fee?
City of Murfreesboro
July, 2007
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Why a storm water user fee?
• EPA
• Maintain and replace infrastructure
• Improve stream water quality
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State and EPA requirements
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Murfreesboro
Designated urban area
EPA requires
MS4 program
Ensure water quality in local bodies of
water
• Requires milestones to met-need
equipment, training, staffing
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Maintain & replace infrastructure
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Infrastructure
In place some time
Pipers clog
Impede storm water flow
Open ditches gradually fill
Vacuum and water jet trucks
Replace with BMP
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Improve stream water quality
• Murfreesboro streams impaired
• Streams may not be suitable for certain
aquatic life/human recreation
• Monitoring/research useful-aid in stream
quality
• BMP
 Bio retention area, debris catchments, bank
restoration
• Improve water quality
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Public outreach & education
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Public out reach
Ensure water quality
School education program
Workshops
Low impact development
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BMP improvement
• Restoration
• Habitat
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What is an impervious
surface?
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Rainwater cannot infiltrate
More water volume-runoff into storm drain
Storm water fee
Median impervious area of single family
residential [SFU] propertied-3,470 sq ft
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What is an impervious
surface?
• Review of 20,000 + properties
• $3.25 per month
• Commercial property- how many
equivalent SFUs
• Commercial – 34,700 sq ft = 10* $3.25=
$32.50
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How fee billed?
• SFU-added to bill
• Apartment-bill property owner
• Commercial- bill property owner
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What is goal of storm water
fee?
• Maintain water quality
• Allow city to comply – federal-state
regulations-unfunded mandate
• Flood damage reduction/drainage
• Long term maintenance
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What is goal of storm water
fee?
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Protect water supply
Stream restoration
BMP-road construction
Education for schools
Workshops for better water quality
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What can you do for clean water?
• Conserve water
• Keep grass clipping out of stream
• Keep restaurant and business waste away
from rain
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What can you do for clean water?
• Use min herbicides/fertilizers & keep off
paved surfaces
• Pick up pet waste
• Report water pollution
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More information
• And other slide shows
• http://www.murfreesboro.gov/government/
water_sewer/stormwater.htm
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What really goes down there?
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Rain Garden Rain Water
Management Option
At Middle Tennessee State
University
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History
• This power point is the result of work
completed by MTSU students in ABAS
3370 and 4370 at MTSU. Mr. L. Sizemore
and Dr. W. Anderson have worked with
MTSU students since Fall 2005.
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What is currently used to manage
rain water at MTSU?
•Gutters for roof runoff
•Surface drainage ditches and an
underground drainage system.
•Ditches or tiles direct water to a central basin
next to Rutherford Blvd.
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What are some of the problems
caused by these methods?
• Petrochemicals and metals are washed off
with storm runoff water.
• Rain water and runoff water can dissolve
the limestone bedrock.
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MTSU Campus Map
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Blowup of MTSU campus map
and drainage ditch (blue)
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Location of Rain Gardens One,
Two and Three
• Rain Garden One (2005) is near the MTSU
campus greenhouse (GH)
• Rain Garden Two (2006) is near the
Horticulture Center (HC)
• Rain Garden Three was completed in Fall
2007 in drainage ditch.
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Surface Drain system being
retrofitted with Rain Gardens (RG)
Green
house
RG 1&2
Commonsunderground
drain line
RG3
Basin
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Runoff from curb cut into Rain
Garden Three (lot # 66)
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Surface drainage ditch on
campus parking lot #66
• The photo looks North toward the campus
greenhouse and Rain Gardens One and
Two.
• Rain Garden Three (F-2007) has been
constructed in drainage ditch
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Alternative ways of dealing
with runoff?
• Direct water to a naturalized setting.
• Minimize runoff of average rain by 90%,
allowing rain garden (plants and soil)
• Filter pollutants-sediments, dissolved ionsbefore percolates into groundwater.
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What is a decentralized runoff
management system?
• Runoff water directed into rain gardens
• Plant canopy and soil can store excess
water.
• Rain Garden, shallow basin allows runoff
water to percolate through the soil and
transpire through the plants.
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How does a decentralized
system work?
Two ways:
1) Plant canopy (trees, shrubs, un-mowed
grasses)
A) increase evapo-transpiration
B) reduce water percolation.
2) Rain garden soil is a sponge for
runoff water
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MTSU Agribusiness and Agriscience
(ABAS) courses-time line
• ABAS 3370: Soil Analysis class began
Rain Garden One the Fall 2005.
• ABAS 4370: Soil & Water Conservation
class completed Rain Garden One the
Spring 2006.
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MTSU Agribusiness and Agriscience
(ABAS) courses-time frame
• ABAS 3370 class began and finished Rain
Garden Two the Fall 2006
• Rain gardens One & Two collect runoff
from gravel parking lots West and North of
the Horticulture Center
• Runoff water contains lime dust
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Decentralizing the pre-existing
drainage system at MTSU
• ABAS 3370 in Fall 2007 built Rain Garden
Three in the drainage ditch
• Planted in F 2007 and Sp 2008
• Horticultural Center to the drainage basin by
Rutherford Blvd (approximately ½ mile).
• Additional Gardens will be built in drainage
ditch
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Surface Drain system being
retrofitted with Rain Gardens (RG)
Green
house
RG 1&2
Commonsunderground
drain line
RG3
Basin
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Looking North toward Rain
Garden One
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Before Rain Garden One, Fall
2005
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Survey in Rain Garden one (Fall 05)
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Checking land elevation after
excavation F 2005
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Digging out Rain Garden One (F 05)
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Rain Garden One excavation
completed in October 2005
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Water in excavated Rain Garden
One-spoil piles in trees Sp 2006
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Spoil piles in background-gravel at
entrance Rain Garden One-Sp 06
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Water in excavated area for Rain
Garden One Feb 06
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Rain Garden One, Water filled after a
rain storm Feb 06
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Mar 06 adding and leveling prepared mix
to Rain Garden One
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Mar 06 leveling pooling area of Rain
Garden One
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Completing initial work on berm for
Rain Garden One (Sp 06)
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Rain Garden One, Spring 2006
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Rain Garden One
• Deeper and longer than needed in a
residential landscape
• Why?
• It had to fit in an existing drainage ditch
surrounded by parking lots.
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How to Plan a Rain Garden
• Garden is down slope from the area it is
draining.
• Small rain gardens are easier to
maintain than one large rain garden.
• Garden should be greater than 10 feet
from building foundation.
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Building Rain Garden Two:
Placement
• Rain Garden Two is on the East side of
Horticulture Center.
• Captures water from the graveled lot on
the West side of the Horticulture Center.
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Other Placement Considerations
• Do not place over a septic system or where
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water pools more than 5 days.
The garden soil should drain well.
How a soil drains can be determined by
watching the site after a rainfall event
 Does it drain within 2 to 3 day
 If not infiltration and percolation rate can be estimated.
• Clay soil or compacted soil can be amended to
improve infiltration and percolation.
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What is water infiltration?
• How quickly does water move into a soil?
• Watch a possible area after a rain fall
event.
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What is the percolation rate?
• The percolation rate is the time it takes for
one inch of water to pass through a soil.
• The ABAS class used these perc rates:
<60 minutes/inch
60-75 minutes/inch
>75 minutes/inch
• A good rate for a rain garden is <60
minutes per inch.
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How to determine percolation rate by soil
texture?
• Using a post hole digger, dug holes 6 to 8 inches
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for a shallow basin or 24 to 36 inches for a deep
basin.
For faster than 60 minutes per inch
 Excavate soil has a medium or fine textures
subsoil
 Or fine reddish textured subsoil
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How to determine percolation rate by soil
texture? (continued)
• For 60 to 75 minutes per hour
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 Excavated soil is reddish fine textured subsoil
to at least 24 inches and yellow clay between
24 to 36
For slower than 75 minutes per inch
 Excavate soil with bed rock within 36 inches
 or soil having a yellowish, grayish, or blackish
fine textured subsoil
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Texture by feel flow chart
• http://soils.usda.gov/education/resources/k
12/lessons/texture/
• Fine texture soils: Sandy clay, Silty clay
and clay
• Medium texture soils: silt loam, loam,
sandy clay loam, clay loam, silty clay loam
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Rain Garden 0ne –before mixing
sand
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Spreading sand in Rain Garden
One
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Spreading sand before tilling
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Because Rain Garden One was
large –tiller used
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Rain Garden One-one pass with
tiller after spreading sand
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Rain Garden One- tilling in sand
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Rain Garden One –tilling and
shovel work
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Rain Garden One-mixing in sand
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Building Rain Garden Two:
The Percolation Rate
• Dug holes to 24 inches, excavated soil in the
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proposed Rain Garden, was medium textured.
1” gravel in bottom, filled holes with 6” of water
and record time to drop one inch. Stuck a tooth
pick in the side of the hole for measuring water
drop.
Measured, 15 minutes per ¼” water drop, or 60
minutes per 1” water.
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Building Rain Garden Two:
Sizing?
• The size of the rain garden can be
calculated.
 Residential size: 100 to 300 sq ft
• The size required to capture surface runoff
around the HC was determined by Mr.
Sizemore’s observations.
 Dimensions: 8 feet x 24 feet by 6 inches deep
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Finding the Area Rain Garden
• If rain garden catch water from a rain
spout, use that part of the roof area.
• Lawns, graveled or paved driveways,
additional runoff water for a rain garden.
• The area to be drained can be multiplied
by a size factor to determine area of rain
garden.
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Size factors are determined according to the type of soil
and the depth of the garden and differ if the garden is
<30’ or >30’ from a building
<30
Feet
3-5”
deep
6-7”
deep
8”
deep
>30 feet
For all depths
Sandy
Soil
0.19
0.15
0.08
Sandy Soil
0.03
Silty
Soil
0.34
0.25
0.16
Silty Soil
0.06
Clayey 0.43
Soil
0.32
0.20
Clayey Soil
0.10
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% Slope Relates to the Depth
of the Rain Garden
• For slopes <4%, the garden depth should
be 3-5 inches deep.
• Between 5-7%: 6 to 7 inches deep
• Between 8-12%: about 8 inches deep
• For slopes over 12%, a rain garden will
take a great deal of fill, another location
should be considered.
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Calculating the Slope & Area
of the Rain Garden
• Drive two stakes about fifteen feet from each
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other (one uphill, one downhill).
Tie a string level to each stake and adjust it to
make it level.
Measure height difference between the
ground and the string in feet, divide difference
by the distance between the two stakes.
Multiply by 100 to get the percent slope.
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Defining the Shape of the
Rain Garden
• Shape should be aesthetic.
• Recommend, length of the garden be
perpendicular to the slope, will catch as
much water as possible.
• Garden should be twice as long as it is
wide.
• Width should be no more than 10-15 feet.
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Building MTSU Rain Garden
Two: Digging
• Mark the perimeter of the garden.
• Front end loader was initially used; for residential
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garden use a garden tiller .
District conservationist (NRCS) showed the class
how to measure slope with a laser level. It is
easy to do with a string and line level.
The inlet was higher than the outlet and the
bottom of the garden was leveled.
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Digging a Rain Garden
• Hammered stakes around the perimeter and ran
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string level between stakes across the middle of
the garden.
Dig the bed level at the desired depth with rakes
and shovels.
Use the removed soil to build a berm on the
downhill edge of the garden.
Covered channel above and below inlet and
outlet with landscape fabric and gravel
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Building Rain Garden Two:
Planting
• The 2006 Soil Analysis class planted
native bushes and perennials.
• The arrangement was done in a naturalistic
fashion using odd number groups.
• Odd number groups ease future
maintenance of the Rain Garden.
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Planting a Rain Garden
• Rain garden plants should be tolerant of
moist and dry conditions.
• Commercial landscape plants can be used
but consider native plants.
• Plant density should be higher and more
naturalistic looking than commercial type
plantings.
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Spreading Mulch in Rain Garden
Two, Fall 2006
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Building Rain Garden Two:
Mulch and Rock
• Placed landscape fabric at the entrance of
the Rain Garden.
• Covered the bottom of the Rain Garden
with double-shredded mulch to the desired
depth.
• Covered the landscape fabric at the
entrance with river rock.
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Rain Garden Two, Finished
Product, Fall 2006
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Looking South from Rain Garden One
toward Rain Garden 3 before its
Excavation in Fall 2007
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Rain Garden Three Specs
• Infiltration Rate
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 3 inches in 90 minutes
Depth
 7 inches
Materials Used
 river rock, landscape fabric, recycled concrete
(from construction site on campus), native
plants.
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Plants Used
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River Oats - Chasmanthium latifolium
Swamp Milkweed – Ascelpias incrnata
Red Twig Dogwood - Cornus sericea
False Sunflower – Heliopsis helianthoides
Helberd Leaf Rose Mallow – Hibiscus laevis
Inkberry Holly – Ilex glabra
Winterberry Holly – Ilex verticillata
Big Blue Lobelia – Lobelia siphilitica
Common Rush - Juncus effusus
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Construction of Rain Garden
Three During Excavation
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Construction of Rain Garden
Three after Excavation
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The only outlet for parking lot 66. The dark
soil is a result of oil and other pollutants
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Rain Garden Three: Excavation
Notice the normal red clay
Notice oil polluted clay
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Dr. Anderson Points out
Contaminated soil
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River Rock
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Spreading River Rock-covering
landscape fabric
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Landscape Fabric
Although fabric
is beneficial to
prevent weeds,
it does not
allow the rock
to settle. Notice
how the fabric
and rock
washed away
due to heavy
rain.
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Landscape Fabric Correction
We corrected
the problem
with recycled
concrete and
rocks to hold
the fabric in
place and to
slow down the
water flow.
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Rain Garden Three; Completed,
F 2007-lime dust on river rock
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In Summary
• Environmental problems caused by surface
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drainage in developed areas can be reduced
by changing landscape practices.
Limit mowed lawn space and raise mower
blade to increases plant canopy.
Stacked Rain gardens in the landscape allow
excess water to infiltrate the soil in many
places before water flows to lowest elevation.
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Plant Lists
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Plant lists will be available on request from:
1. your local extension office
2. Tennessee Master Gardeners
3. web search: rain garden plants
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Rain Garden One –Su 2008looking South
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Rain Garden One-Su 2008
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Berm at end of Rain Garden
One-Rain Garden Two to right
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Rain Garden One looking NorthSu 2008
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Entrance to Rain Garden One on
North Side looking East-Su 2008
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Rain Garden Two-su 2008
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Rain Garden Three looking
South- Su 2008
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Rain Garden Three looking
South-Su 2008
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References
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1.) http://clean-water.uwex.edu/pubs/raingarden/
2.) http://raingarden.il.gov/create.htm
3.) Prince George County Bioretention Manual
4.) Rain Gardens- solving drainage problems, Tennessee Gardener,
August 2005
5.) Land Judging Guide, UTK, PB 727
6.) www.cleanwaterccampaign.com/what_can_I_do/raingarden.html
7.) Estimating Soil Texture, GardenNotes #214,
www.cmg.colostste.edu
8.) Guide to Texture by Feel,
http://soils.usda.gov/education/resources/k_12/lessons/texture/
Rev 3-10-07, 3-15-07, 4-4-07,June 3, 2008
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Fact sheet- Rain Garden Design
• http://www.lowimpactdevelopment.org/raingarden_design
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/links/htm
http://www.dof.virginia.gov/rfb/rain-gardens.shtml
http://www.utk.edu
Construction
Cost
Cost of Not
What is a Rain Garden?
Man-made depression; Improve water quality
Bioretention area: 1.) Collect water runoff, 2.) Store it, 3.)
Filtered slowly-Nutrient removal
How? Contact with soil and plant roots
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Fact sheet- Rain Garden Design(2)
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Who Should Create a Rain Garden?
Suitable any land use; Residential, commercial, industrial
Place so impervious surfaces drain into depression
Grass buffer strip
Slows water entering rain garden; Surface filters
particulates from runoff
• Pond area
• Depression area, stores water; Evaporation; Particulate
not filtered to settle to bottom;
• 6 inch depth; Not pond more than 3-4 days – avoid
mosquito breeding
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Fact sheet- Rain Garden Design(3)
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Who Should Create a Rain Garden?
Suitable any land use; Residential, commercial, industrial
Place so impervious surfaces drain into depression
Grass buffer strip
Slows water entering rain garden; Surface filters
particulates from runoff
• Pond area
• Depression area, stores water; Evaporation; Particulate
not filtered to settle to bottom;
• 6 inch depth; Not pond more than 3-4 days – avoid
mosquito breeding
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Fact sheet- Rain Garden Design(4)
• Components of a rain garden
• Mulch/Organic Layer
• Decomposed organic material; Removes metals; Shredded
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hardwood mulch
Planting Soil
Leaf mulch (20%), sandy soil (50%) and 30% top soil; Clay particles
adsorb
Planting Selection
Species that tolerate extremes, perennials
Site Considerations
Site: Intercept water runoff
Bioretention area: 5 to 7% of drainage area (example ¼ roof area)
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Fact sheet- Rain Garden Design(5)
• How to Design a Rain Garden?
• Tennessee – Murfreesboro Water and Sewer Department
• http://www.murfreesborotn.gov/government/water_sewer/stromwater/
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residents.html
Harpeth River Rain Gardens for Backyards
http://www.harpethriver.org/backyard_raingardens.html
Maintenance: Dry, Spring
Plant Lists http://www.tneppc.org
Local nurseries of Tennessee Nurseryman’s Association
Questions: Rutherford County Extension office: 898-7710
Brown bag lecture, 4th Thursday of each month June 21 from 11:3012:30, 315 John Rice Blvd
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