Jordan Cove Urban Watershed Project

CASE STUDY FROM WATERFORD, CONNECTICUT
Jordan Cove Urban Watershed Project:
Long-Term Monitoring of a
Low Impact Development Neighborhood
QUICK FACTS
Theme
Monitoring
Name
Jordan Cove Urban
Watershed Project
Unique LID
Components
One of the first LID
monitoring studies, paired
watershed study, baseline
and post development
data, cost data, 10 year
project
Location
Waterford, CT
Land Use
Residential
Introduction
Watershed
Area
When the Jordan Cove Urban Watershed Project first began in the early
1990’s low impact development (LID) was not a common term. However,
LID site is 4.2 acres,
EPA’s Nonpoint Source Program wanted to determine how useful these
control site is 14 acres, and
new best management practices (BMPs) for stormwater management
traditional site is 5 acres
could be to reduce stormwater runoff pollution through a ten year
monitoring effort. Cleaning up Jordan Cove using BMP neighborhood
Lessons
Learned
Participant-focused public
designs and practices is important since Jordan Brook flows into the Long
outreach needed and
Island Sound, which is impaired for fecal coliform bacteria and
daily rain fall information
experiences periods of low oxygen (hypoxia) and no oxygen (anoxia).
is important
Promoting Innovative Stormwater Solutions
for Coastal Plain Communities
CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
Jordan Cove Project
Check out the Jordan Cove interactive tour
that includes not only final reports, pictures,
and designs but also interviews with the
major players. This is available online at
http://nemo.uconn.edu/about/news.htm
This monitoring project, conducted from 1995 to 2005,
compared stormwater runoff characteristics in three
residential watersheds within Waterford, CT’s Jordan
Cove area: 1) an older neighborhood (control), 2) a
traditional design neighborhood, and 3) a BMP
neighborhood. Table 1 depicts watershed area,
and gutter to convey stormwater runoff from the
impervious cover, and additional site details for each of
site to the stormwater BMPs
these three neighborhoods.
o
Jordan Cove included the following BMPs:
Pervious pavers were used instead of asphalt for
roadways
Raingardens (Figure 1);
o
Fifty foot cul-de-sac was replaced with a one way
cul-de-sac and bioretention area in the middle
Cul-de-sac bioretention (Figure 2);
Grassed swales in town right of ways; and
Cluster development pattern (Figure 4);
Pervious paver roads (Figure 3) and driveways
Zero lot line setbacks allowed home construction
(Figure 6) using Uni-Ecostone®.
closer to the property lines and reduced front setbacks
allowed home construction closer to the front of the
Jordan Cove’s Better Site Designs (BSDs) included:
lot to preserve the community’s natural land;
Town of Waterford, CT waivers for the BMP
Open space- a portion of the natural landscape was
neighborhood;
permanently protected;
o
Reduced road width from 28 ft to 20 ft
o
Grassed swales were used instead of typical curb
Shared driveways reduced impervious cover;
Low to no mow areas were designated on each lot;
Jordan Cove Mix- a custom grass seed mixture that
aimed to reduce fertilizer and herbicide application;
and
Education and outreach to homeowners through
workshops and yearly surveys.
In order to accomplish this project several key elements
fell into place and the following project team partners
included: John Lombardi- a willing, capable developer;
Dr. John Alexopoulus and Dr. Karl Guillard -early
Figure 1. Raingarden in Jordan Cove resident's yard. Photo
courtesy of University of Connecticut. natural resource planning and consultation;
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
Figure 2. Bioretention in cul-de-sac. Picture courtesy of
University of Connecticut.
Figure 3. Ecostone pavers were used for the road and
driveways. Picture courtesy of University of Connecticut.
Dr. John Clausen- a flexible and competent
Monitoring Study Design
research leader;
The Jordan Cove Urban Watershed Project had three sites
The Town of Waterfront, CT’s Steve Stedman and
Tom Wagner- flexible town planning division and
public works that eased local fire and safety
concerns;
shown in Table 1 that included an already built traditional
development (control), a traditional development, and the
BMP neighborhood. There was a calibration period for each
project site for about two years to determine baseline
conditions for all sites. This calibration period is extremely
Education and outreach- University of
important since the true pre-development stormwater runoff
Connecticut’s Nonpoint Education for Municipal
rates were measured and compared to the post control runoff
Officials (NEMO) provided expert, long term
rates. The traditional and BMP neighborhoods were
outreach;
monitored during development and two years after
Federal and state agencies (US EPA through the
construction (post construction phase). Figure 5 depicts
CT Department of the Environment Protection’s
monitoring onsite. The monitoring aspects of the Jordan
319 Nonpoint Program) - needed more
Cove project examined both stormwater quality and runoff
information about new and upcoming BMPs; and
quantity in each of the three watersheds. Sites were
Residents- willing to buy cluster development and
land with different deed restrictions as well as a
neighborhood that served as a research site.
monitored for suspended solids (sediments), and common
stormwater pollutants (such as nitrogen, phosphorus, fecal
coliform bacteria, copper, lead, zinc, and biochemical oxygen
demand). These stormwater runoff pollutants can harm
wildlife and humans. In Jordan Cove, the process to plan,
develop, monitor, and communicate findings to various
stakeholder groups was documented to serve as a learning
tool for similar projects in the future.
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
Figure 4. BMP neighborhood landscape plan (top) and aerial view (bottom). Landscape plan developed by Dr. John
Alexopoulos and aerial photo courtesy of John Walsh and the University of Connecticut.
(http://www.jordancove.uconn.edu/jordan_cove/publications/drawings/jordan_cove_10_of_14.pdf).
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
Table 1. Jordan Cove Urban watershed project sites (Clausen, 2007).
Project Sites
(neighborhoods)
Watershed Area
(ha)
Stormwater
Management
Impervious
Cover (%)
Number of
Lots
Lot
Size
(ha)
Construction
Period
Control
1.5
(already developed)
(~14 acres)
Typical Curb and
Gutter
29
43
0.16
1988
Typical Curb and
Gutter
32
17
0.15
1999 to 2002
LID BMPs
22
12
0.10
1997 to 2003
Traditional
BMP Development
2.0
(~5.0 acres)
1.7
(~4.2 acres)
Figure 5. Monitoring water quality and water quantity for Jordan Cove. Pictures courtesy of University of Connecticut.
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
In addition to the water quality and water quantity studies
considering education and outreach efforts in a monitoring of the entire watershed, researchers conducted
project and interpreting the results for Jordan the following studies to assess more discreet conditions in the
Cove.
BMP neighborhood:
Study Results
The Driveway Study compared six driveways that tested
The project’s main focus was to determine if
asphalt, Uni group EcoStone ® interlocking concrete
innovative BMP stormwater management practices
pavers (Figure 6), and crushed stone in the BMP
(LIDs) reduced the amount of stormwater runoff from
neighborhood. The study found that runoff depths
the site and resulted in better water quality.
decreased as follows: asphalt > pavers > crushed stone.
Weekly continuous flow weighted sampling occurred
Asphalt discharged water after 1 minute while pavers
before construction (calibration), during construction,
and crushed stone discharged water after 20 minutes
and post construction. A large majority of pre-
from water application. The pavers and crushed stone
development rates are modeled based on irrelevant
clearly promote infiltration much better than asphalt and
data (e.g., rainfall in other regions, curve numbers
pavers and crushed stone has significantly lower
inappropriate for the site, etc.). Jordan Cove’s paired
pollutant runoff than asphalt.
watershed project is unique because it contains that
The Lawn Nutrient Study monitored twelve lawns that
pre-development measurement period and uses it to
represented the range of lawn practices in all three
compare the post-development changes.
neighborhoods. Although differences were found on a
The BMP neighborhood controlled stormwater runoff
lot by lot basis and over time, the lawns with BMPs had
(runoff volume and peak discharge) but experienced
less nitrate. This indicates that their pollution level is
increased sedimentation during BMP construction
lower.
(here swale construction). BMP site stormwater runoff
The Household Survey was conducted in all three
volume stayed below the pre development stormwater
neighborhoods each year. The survey goal was to
runoff rates during and after construction (Bedan and
determine resident’s pet waste, lawn care, watering, leaf
Clausen, 2009). The traditional neighborhood
disposal, rain gutter outlet disconnection, and car
experienced high urban stormwater runoff volume
washing practices. Also, project updates were provided
problems at levels twice as high compared to the BMP
to residents at this time. Results from the surveys
site. The BMP site continued to release sediment
showed that BMP residents mulched leaves compared to
downstream, but recent testing around the time of the
the control neighborhood residents who preferred
report (2007) found low sediment export. Similar to
bagging the leaves. Pet waste practices, car washing
the sediment story, the nutrients (total phosphorus,
practices and proximity to storm drains, and lawn care
nitrate-N, and TKN) were high during construction
practices (fertilizing) practices did not have a
and post construction. Also, the paver road’s
measureable difference in the two neighborhoods. In
infiltration rate was less than expected during
addition, over the study period (1999 to 2004) there construction, but improved later (2001 to 2005).
were no measurable neighborhood differences in Even though sediments and nutrients were higher post
resident behavior. This is an important finding when development than pre development the concentrations
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
Figure 6. Pervious pavers were used in the driveways. Picture courtesy of University of Connecticut.
were not excessive and the ability to detect this difference
natural resources were better protected from increased
could largely result from the excellent experimental set up
stormwater runoff volume after a storm than the
(i.e., two year calibration period measuring the actual pre
traditional neighborhood (e.g., one measured storm
development rates and careful BMP development that
showed that the BMP stormwater runoff time was
yielded excellent monitoring results).
four times slower than the traditional neighborhood).
During and after construction the traditional
In the traditional neighborhood stormwater runoff volumes
neighborhood had low sediments and nutrients. Dr.
(peak discharge) were extremely high due to the impervious
Clausen noted that only smaller rain events occurred
surfaces constructed through the curb and gutter system.
during the 10 year study period and the highest event
These systems prevent flooding by quickly removing
was a 5 year rain event. Currently, he is in the process
stormwater off site through the curb and gutter system, but
of reevaluating the rainfall data for better data increase the runoff volumes and cause erosion problems interpretation. Dr. Clausen also noted that measuring
downstream. Additionally, the decreased time for pollutant
groundwater would be beneficial to future studies
transformation results in more polluted water leaving the site
(Dietz and Clausen, 2008). The BMP watershed downstream
although Jordan Cove did not measure groundwater.
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
Including BMP stormwater management practices in
Lessons Learned
Jordan Cove proved more expensive than traditional
The Jordan Cove Urban Watershed Project was a
development and stormwater management practices.
forefront LID development and research endeavor.
Using BMPs took more design time, more time to get
Jordan Cove provides the following important “lessons
the necessary permits and waivers, and the cost of
learned" from this project can help improve similar
pavers was higher than asphalt. However, the cost of
efforts in the future.
crushed stone was less expensive than asphalt. The
1.
comparison in construction costs between the three
Cluster design worked- This helped preserve natural
resources and decrease impervious surfaces (e.g.,
neighborhoods is shown in Table 2 (Table 33 in
roads and roofs);
Clausen, 2007).
2.
The BMP neighborhood site protected the receiving
Need LID ordinances- The project needed several
waivers;
waters from excess stormwater runoff during and after
construction. Using better site design to develop
3.
Simple stormwater disconnections should be
around natural resources and implementing
developed during the planning stage (e.g.,
alternatives to asphalt such as porous pavers and
downspout disconnection);
crushed stone in conjunction with the LID stormwater
4.
management practices was successful (Hood et al.,
Heavy equipment causes soil compaction that
damaged rain garden and swale infiltration- Use
2006).
temporary roads for heavy equipment access;
In summary, this project was a success both through
5.
improved stormwater management on site that was
LIDs are vulnerable to erosion before stabilizedErosion and sediment control is needed until the
demonstrated by thorough sampling over a long period
LID is stabilized;
of time. The project is unique because the monitoring
6.
period was ten years and this was one of the first of its
On site supervision during construction is needed
kind in the country. Public communication is an
during LID construction since contractors may be
integral component in Jordan Cove but the yearly
unfamiliar with LID features. For example the
survey did not change resident’s behaviors, so
contractors automatically applied loam fertilizer to
additional education and outreach are needed to
the grassed swale even though a soil test showed this
produce results. Although nutrient and sediment
was not needed (and this fertilizer resulted in excess
concentrations increased during construction and post-
pollution downstream);
construction important lessons were learned: 1) careful
7.
detail on site is needed to ensure swales are stabilized
LID BMP maintenance education is needed for
homeowners and maintenance crews;
and protected from storm events until that time and 2)
8.
fertilizer application in the swales contributed to
Education and outreach component should include
experts in the field for improved approach during
nitrogen and phosphorus spikes downstream.
study and better translation to the end users; and
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
a.
As Dr. Clausen said in the video interview on the
produced for Jordan Cove Urban Watershed Project that
Jordan Cove CD, explaining to homeowners why
details the LID practices, provides in-depth technical
behavioral changes should be made and how to
information, and shows interviews from project
accomplish those changes is not enough and
participants.
proved ineffectual in this case
9.
Jordan Cove’s Urban Watershed Management Plan
LID costs and benefits were difficult to assess-
documents the LID process for the developer, engineer,
Bringing in an economist or LID cost expert will
scientist, resident, local officials, additional stakeholders
improve LID value estimates.
to show the benefits for LID and opportunities to improve
the process. Low Impact Development implementation is
Through the Jordan Cove Urban Watershed project we
a way to responsibly develop and protect the natural
learned that the LID worked in the BMP neighborhood by
resources we depend on and appreciate.
reducing the water quantity that came off the site through
stormwater runoff and that some pollutants were reduced
Contact Information
but sediments and phosphorus were not reduced as much
John Clausen
as hoped. Jordan Cove is one of the earliest examples for
Professor, University of Connecticut
stormwater BMPs and LIDs. Jordan Cove taught us that
Department of Natural Resources
local codes and ordinances need to be flexible to allow
Management and Engineering
LID and BMP familiarity is needed across the board for
1376 Storrs Rd., U-4087
the developers, engineers, researchers, residents, public,
Storrs, CT 06268-4087
local planning and stormwater localities. A wide variety of
[email protected]
individuals and groups, including developers, engineers,
Phone: 860-486-0139
researchers, residents, public, local planning, and
For more information visit:
stormwater localities need to become more familiar with
http://www.jordancove.uconn.edu/
LID. Jordan Cove is one of the first LID communities
where long term monitoring showed the obstacles and
For copies of the UConn and CT NEMO’s Jordan Cove
opportunities from better stormwater management
CD visit http://nemo.uconn.edu/about/news.htm
practices in neighborhood development.
Photos courtesy of the University of Connecticut from
The University of Connecticut’s College of Agriculture
Jordan Cove Urban Watershed Project
and Natural Resources and CT NEMO developed a
www.jordancove.uconn.edu/jordan_cove/photos.html
comprehensive and easy to use multimedia CD was
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
References
Bedan, E. S. and J. C. Clausen. 2009. Stormwater runoff quality and quantity from traditional and low impact development
watersheds. Journal of American Water Resources Association 45: 998-1008.
Clausen, John C. 2007. Jordan Cove Watershed Project. Section 319.University of Connecticut. Available online at:
http://www.jordancove.uconn.edu/jordan_cove/publications/final_report.pdf
Dietz, Michael E. and John C. Clausen. 2008. Stormwater runoff and export changes with development in traditional and
low impact subdivision. Journal of Environmental Management 87(4): 560-566.
Hood, M.A, J.C. Clausen, and G.S. Warner. 2007. Comparison of stormwater lag times for a low impact development and
traditional residential development. Journal of American Water Resources Association 43:1036-1046.
Hood., M. J., J. C. Clausen, and G.S. Warner. 2006. Low impact development works! Journal of Soil and Water
Conservation Society 60(5):115A-117A
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CASE STUDY: JORDAN COVE URBAN WATERSHED PROJECT
Developed by the
nd
8390 Main Street, 2 Floor • Ellicott City, MD 21043
Funding and support for this project was provided by CICEET, the Cooperative Institute for Coastal
and Estuarine Environmental Technology. A partnership of the National Oceanic and Atmospheric Administration and the
University of New Hampshire, CICEET develops tools for clean water and healthy coasts nationwide.
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