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Winooski Rain Garden Project
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Reducing Stormwater Impacts in Heavily
Developed Areas; Winooski Rain Garden Project
W i n o o s k i R a i n G a r d e n P r o j e c t
S e p t e m b e r 2 0 0 7
The Winooski Rain Garden project
was developed through a partnership between
UVM Extension Lake Champlain Sea Grant
program’s NEMO program and the city of
Winooski. A study of the Morehouse Brook
found it to be severely impaired by stormwa-
ter inputs just below Mallets Bay Avenue.
Winooski, a historic city that is heavily devel-
oped, has little area to build traditional engi-
neered stormwater facilities. In the process of
looking for an alternative way to reduce the
stormwater inputs to the Morehouse Brook,
the rain garden project was developed to dem-
onstrate to residence and business owners the
low cost and low maintenance practice to
manage their stormwater runoff.
Rain gardens originate from the
stormwater practice called bio-infiltration or
bio-retention. This practice mimics an upland
forest’s natural functions of interception, infil-
tration, chemical transformation and ground
water recharge. Rain gardens have a two fold
benefit; reducing stormwater flows and pro-
ducing clean water. This project showed the
versatility of rain gardens as a small residen-
tial garden treating roof runoff, to a large pub-
lic garden treating road runoff, to a small park
garden treating sediment laden stormwater
from a ball field, to the affects of a small gar-
den on parking lot runoff.
The project was funded by the Ver-
mont Department of Environmental Conser-
vation 319 Non-point Source Pollution Pre-
vention Grant in June of 2006. Other partners
in this project include Winooski Environ-
mental Leadership Board, University of Ver-
mont Master Gardeners Program and Ver-
mont Youth Conservation Corps.
Project Preparation
A flier was sent to all Winooski residents in
April as part of the town’s water bill mailing
advertising the rain garden project. The pro-
ject was also advertised in an article written
about the project in the Burlington Free
Press’s local section and through a live call in
program on the local cable access channel.
After receiving many emails and calls about
the project a kick off meeting was held in late
May for interested residents. Site visits to
potential garden locations were conducted by
Emma Melvin. At the same time locations for
the public gardens were reviewed by Emma
Melvin and Erik Bailey.
As part of the education component
of the project, in June, workshops were held
on the function, design and installation of rain
gardens. These workshops were open to the
public. All garden recipients were required to
attend a workshop. Master gardeners inter-
ested in the project were also encouraged to
attend. As part of the workshop, the partici-
pants installed a rain garden at the Winooski
Wastewater Treatment Plant. Twenty three
people attended the two workshops held, and
eighteen people attend the project kick-off
meeting.
North Street Rain Gardens
North Street rain gardens have about a
134,549 square feet watershed draining
into them. Twenty four percent of this
area is covered by impervious surfaces
including houses, roads and driveways.
Not all of these impervious surfaces are
asphalt or concrete, some are dirt and
gravel drives.
These rain gardens were designed slightly
oversized to compensate for the com-
pacted urban soils and somewhat larger
storms volumes (over one inch).
These rain gardens were functioning early
in April and infiltrated the spring snow
melt. They also captured water and sedi-
ment released during a water main break
on North Street above the gardens.
If the only surfaces within the watershed
draining into the rain gardens were the
impervious surfaces (~32,292 ft2) with a
precipitation of approximately 32.6 inches
(storms less than 1 inch) during the time
period the rain gardens were functioning,
these gardens have treated 1,051,750 cubic
feet of stormwater, not to mention all the
sediment captured in the gardens.
W i n o o s k i R a i n G a r d e n P r o j e c t
The Dabb’s garden was designed to capture runoff from 2/3 of the roof . There was a lower tiered garden
installed to capture any overflow from the top garden.
Installation
Garden installation started on July
29 at Jim and Carole Foster’s property, 57
Cedar Street, Winooski. Ten master garden-
ers volunteered for this garden installation.
The installation started with a short explana-
tion of a rain garden, the design and steps of
the installation. This garden treated approxi-
mately 500 square feet of the Foster’s roof.
The garden dimensions were
marked off with wooden pegs and string
prior to the installation. The master garden-
ers started by digging a one and a half foot
deep kidney shaped bowl with gently slop-
ing sides. The excess soils were used in cre-
ating a small berm on outside curve of the
planting bed. After the digging was fin-
ished, the gardeners leveled the bed and the
berm. Compost was mixed with native soils
to create the rain garden soil medium. Two
by four wood planks were laid out during
planting to minimize soil compaction.
Some of the plants in this garden
were donated by master gardeners
(approximately 3 out of the 15 planted). The
garden was mulched with approximately two
inch layer of aged mulch from the Intervale
Compost. The rain water was directed to
this garden through an extension pipe at-
tached to the rain gutter. The entrance of the
garden was lined with pebbles to protect
from erosion and to better disperse the wa-
ter.
The next garden was installed on
August 5, 2006 at Karen McCreas’ property
on 103 North Street Winooski. This garden
treated approximately the same size roof but
the rain water was directed to the garden by
a sloped drip line armored with cobble. This
garden was also installed by master gardener
volunteers.
The public gardens at Landry Park
were installed August 7-11 by the Vermont
Youth Conservation Corps crew. The town
of Winooski excavated most of the gardens
and created the curb cut for the entrance of
the gardens prior to installation. The town
also transported to the site all the gravel used
for the garden entrances and the walkway
from the baseball field. The compost and
mulch was delivered to the site by Intervale
Compost.
On August 7, the first day at
Landry Park with the VYCC crew, Andrew
Gordon from the University of Vermont’s
Across the Fence TV program, came and
filmed the installation and interviewed Eric
Bailey from the city of Winooski, Sally
Dean, the master gardener involved in the
project and Jim Foster, a garden recipient.
On that same day, a reporter and photogra-
pher from the Burlington Free Press inter-
viewed the VYCC crew members and the
project coordinator Emma Melvin. This
article appeared in the Burlington Free Press
the following day August 8. The Across the
Fence show aired early October.
Each of the larger gardens at
Landry Park was installed in a day. Each
was installed with a gravel entrance to dissi-
pate some of the erosive energy of the
stormwater as it enters the garden. An as-
phalt speed bump was also installed below
the curb cuts on the garden located along
North Street. These speed bumps were in-
stalled to help direct the stormwater in the
gardens. The gravel entrances were de-
signed to also allow for some water storage
and sedimentation for any thing being car-
ried in the stormwater. Many of the plants
used in these gardens were donated by mas-
ter gardeners and others.
Two rototillers, one loaned from
the Winooski Parks Department and one
rented from Essex Equipment were used to
un-compact soils in all the of the gardens.
Due to the high use and the common nature
of urban soils, they were of poor quality and
highly compacted. Replacement soils were
purchased from Intervale Compost. These
soils were used in the upper garden located
along North Street.
The next garden installed was for
the Michael Dabb's’ property at 217 Mallets
Bay Avenue. It was a unique garden given
that it crossed underneath the front fence and
was tiered. The upper tier was the main
garden and the lower tier was for overflow.
The upper tier had an earthen berm but the
lower tier had reinforced wooden wall.
Rain Garden Sign to be posted at the public rain
gardens.
R e s i d e n t i a l R a i n G a r d e n s a n d M a s t e r G a r d e n e r s
This project pur-
pose was to dem-
onstrate the uses of
rain gardens as a
viable tool to man-
age stormwater in
an ultra urban envi-
ronment. By part-
nering with the
Master Gardeners
program, this project was able to reach master gardeners
throughout the state and within Chittenden County. Master gar-
deners helped the home owners choose the proper plants for
their garden and how to maintain a healthy garden. They also
generously donated many of the plants used within the rain gar-
dens installed in this project. This highly respected and active
group planted the seed of rain gardens in their local communi-
ties. Stemming from this partnership a rain garden workshop
was presented at the Annual Association of Professional Horti-
culturist meeting and rain gardens and the Winooski project was
featured on the cover page of the Living Section of the Burling-
ton Free Press in July 2007. As part of this projects partnership
master gardener program has been working with Lake Cham-
plain Sea Grant to develop a plant list suitable for Vermont rain
gardens.
Special thanks to Nancy Hullet, Sally Dean, Marc Conpanion,
Tage Lilja and Ann Pearce.
The rain water was directed to the
garden through an extension pipe connecting
to the down spout. A small rock pile was
created at the end of the extension pipe to
dissipate the flow into the garden. Approxi-
mately eight volunteers helped install this
garden.
The last garden installed in the fall
was at the Nocito property at 4 Pine Grove
Terrace. This garden infiltrated one fourth
of the roof and was adjacent to the back
deck. The garden was adjacent to the gutter
and required little directing. This garden
comprised mostly of bushes, most interest-
ingly blueberry bushes and some herbaceous
flowering plants.
Visits were made to the installed
gardens to assess for any problems and en-
sure proper functioning in the fall and the
following spring and summer.
Two rain garden tours were con-
ducted in the fall of 2006 for interested mas-
ter gardeners, state employees, university
faculty and students. 17 people attended the
tours. Two more tours were given in April
2007 for the master gardeners and a Ver-
mont Technical College horticultural class.
An presentation was made to the
Winooski City planning and development
review boards about the project and rain
gardens encouraging them to consider rain
gardens and Low Impact development as a
solution to manage the towns stormwater.
An educational how- to poster was
created for municipalities and others inter-
ested. An informative brochure was created
about the project and was distributed at the
Vermont Farm Show and is currently dis-
played at the State Extension office in Col-
chester. The Across the Fence show and
the brochure is also available now on the
Lake Champlain Sea Grant webpage. The
project was also spotlight in a presentation
made to the New England Conservation
Districts at their annual meeting in Febru-
ary. A workshop on incorporating rain
gardens and other low impact development
strategies focused the Winooski Rain Gar-
den Project was presented at the Town Of-
ficials Education Conference spring of
2007.
Educational signs were designed
by the Maja Smith with the LCBP Wayside
Exhibit Program. This fall the signs will be
posted at the public gardens explaining the
stormwater impact on streams and how rain
gardens function and reduce these impacts.
Identical signs will be posted at rain gardens
installed by Otter Creek, Poultney Met-
towee, and Rutland.
Maintenance
All gardens were visited early
spring to see if any damage was incurred
over the winter. All gardens were function-
ing properly and were infiltrating spring
snow melt.
Plants were added to the North
Street gardens. The North Street gardens
were impacted by a water main break above
the gardens on North Street that washed in
large amounts of sediment. This sediment
covered the lower two gardens about 2 1/2
inches deep. The upper garden received less
sediment with only a thin layer of sediment
over sections of the garden. This sediment
was removed early enough by Emma Melvin
and the volunteer master Sally Dean to incur
no damage to the plants. Sediment depos-
ited into the garden is the largest mainte-
nance issue with the North Street gardens.
Few of the drive ways located in the water-
shed draining into the rain garden are gravel
or dirt. It is quite apparent that these drive-
ways are contributing enormous amounts of
sediment entering into the gardens. The
driveways can be identified by the type of
gravel that appears within the garden. Large
stones were added to the entrance to stabi-
lize the entrance. Much of the smaller
gravel was transported into the garden after
the larger storms and the water main break.
The gravel and sediment built up at the en-
trance of the gardens were removed as part
of the route weeding. Mulch was stockpiled
at the city wastewater treatment plant and
was used to mulch all the public gardens.
W i n o o s k i R a i n G a r d e n P r o j e c t
Sediment and gravels washed into the rain garden entrances at North Street. This is removed as part of
the season maintenance.
Garden edging was added to the gardens to
reduce the weeds within the garden. Sally
Dean has adopted the North Street garden
and has helped maintain these garden this
summer with Emma Melvin. She will con-
tinue this maintenance in the following
years.
All plants that were planted at these
gardens survived this year and will be moni-
tored next year.
The other Landry Park gardens
were damaged during park construction. No
maintenance was completed on these gar-
dens due to the continued construction and
inability of the city securely say that these
gardens would be maintained and restored
after construction.
The gardens located at the waste-
water treatment plant were re-mulched at the
beginning of the season and weeded through
the season. Most plants in these gardens
came back this season.
Stormwater Reduction
Some stream flow monitoring was
completed after the garden installations.
Morehouse Brook is piped under ground for
much of its length. It is first piped under
ground at the industrial park near the head
waters and is piped under North Street and
Landry Park. The flow measurements were
made at the point the stream reappeared
from underground just lower left corner of
Landry Park and where it day-lights again at
Mallets Bay Avenue. Upstream measure-
ments were made but were hard to compare
to the downstream measurements due to the
industrial park’s stormwater detention pond
in which the stream drains into prior to it
being piped underground. With the means
available no flow measurements could be
made directly upstream of the North Street
rain gardens to assess the actual decrease in
stormwater flow entering the stream. Esti-
mates were made of decreased stormwater
for each rain garden for the functioning pe-
riod of the garden by calculating the rain fall
and multiplying it by the drainage area of the
rain garden (Figure 2). The precipitation
data used for this calculation was taken from
the NOAA National Weather Forecast Of-
fice webpage for Burlington (Figure 1). The
time period used does not include periods
during the winter when the gardens were
filled with snow. For the residential gar-
dens, the total rain fall was used since resi-
dence noted that their rain gardens never
filled. For the Public gardens only storms 1
inch or less were used in the calculations.
Though rain gardens did infiltrate snow melt
this was not included in the calculations.
Figure 2. Winooski Rain Gardens
Infiltrated Stormwater
Garden Drainage
area
Infiltrated
Rain
Foster 500 ft2 19,495 ft3
Dabb 850ft2 26,928 ft3
McCrea 500 ft2 18,020 ft3
Nocito ft2 7,920 ft3
North Street 32,292 ft2 1,051,750 ft3
Wastewater
Treatment 600 23,394 ft3
Figure 1. Precipitation After Rain
Gardens Installed
Gardens
Installed Date
Inches
of Rain
Rain
Events
Above 1
Inch
Aug-07 1.46 b
Jul-07 6.29 2
Jun-07 2.26 b
May-07 1.95 b
Apr-07 3.79 1.27
Mar-07
Dec-07 3.84 1.74
Nov-07 2.62 b
Nocito Oct-07 6.25 1.96
Dabbs Sep-06 3.22 b
McCreas &
Landry Park Aug-06 4.36 1.5
Fosters &
Waste Water
Treatment
Plant Jul-07 2.95 b
Total
Rain 38.99
Nocito garden has an assortment of shrubs including
summer sweet and blueberry bushes.
S u r v e y R e s u l t s a n d C o m m e n t s 1) Have you seen pooling in your garden?
McCreas: Yes, I have seen pooling, but only in the middle of a
very heavy rain storm (remember, I also funnel water from the
back roof into the garden, AND we built it a tad larger than was
originally anticipated).
Foster: No standing water at all.
Nocito: There has not been any pooling in our garden.
2) Have all the plants survived?
McCreas: I lost one plant over last winter.
Foster: All survived
Nocito: All of our plants survived beautifully
3) Are you satisfied with the gardens performance?
McCreas: The garden is wonderful - it also supported a large
gaggle of bird-planted sunflowers all summer. The best display of
sunflowers I have EVER had.
Foster: Absolutely
Nocito: We love our garden! It performs great!
4) Have you talk to other people about rain gardens?
McCreas: Yes, I talk to people about the rain garden ...... and
thanks for the Free Press referral!
Foster: Constantly, a couple who I have talked to has put one in
or have plans too. People who talked to ask more questions about
putting one.
Nocito: Yes we have talked with other people about our garden.
5) Do people ask you about your rain garden?
McCreas: Thanks to the Free Press article, lots of people ask me
about my rain garden.
Foster: No neighbors this year but neighbors on each side asked
last summer.
Nocito: People cannot see ours unless they are in our backyard,
but typically if I bring it up they ask more about it.
Winooski Rain Garden Locations
Public Garden Locations:
Landry Park-
3 gardens on North Street along Park fence
1 gardens within park adjacent to bleachers
1 garden within park adjacent to baseball field dugout
Winooski Wastewater Treatment Plant-
2 gardens adjacent to parking lot
Private Garden Locations:
217 Mallets Bay Avenue
57 Cedar Street
103 North Street
4 Pine Grove Terrace
This project was funded by a Vermont Agency of Natural
Resources, Department of Conservation Non-point Source Pollution
Control Grant, and by the CSREES USDA New England Regional
Water Quality Project, award number USDA 00-51130-9775.
W i n o o s k i R a i n G a r d e n P r o j e c t ,
p r o t e c t i n g o u r w a t e r w a y s t h r o u g h g a r d e n i n g
Picutres taken during the Winooski Rain Garden
Porject.
University of Vermont
63 Carrigan Drive
Burlington, VT 05405
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