Enhancing Low Impact Development Designs Using Manufactrured BMP's

ENGINEERED SOLUTIONS
Enhancing LID Designs
Using Manufactured
BMP’s
A Collection Of Case Studies That Show
How Manufactured BMP’s Contribute to Low
Impact Development
2014 | www.ContechES.com/Stormwater-Blog

How Manufactured BMP’s Contribute to Low Impact Development
2 3
What makes a
stormwater design
green?
Urban stormwater planning has two fundamental purposes, minimizing the impact of increased runoff quantity and
preventing pollutants from migrating to our natural waterways through stormwater conveyance systems. Natural systems
comprised mainly of soil, plants and associated microbiological communities perform these functions with remarkable
effectiveness in natural environments. Compared to unmitigated urban landscapes, most undeveloped areas generate
lower runoff volumes, lower peak flow rates, shorter runoff durations and more moderate runoff temperatures. What
runoff does occur is relatively free from urban pollutants like hydrocarbons, fertilizers, heavy metals and bacteria. Green
or low impact urban stormwater systems provide these same critical stormwater quality and quantity management
services, although given engineering and land availability constraints, they may take a decidedly engineered form.
The case studies presented here are real project examples where manufactured stormwater management systems were
integrated into the site design to restore predevelopment hydrology and to minimize pollutant discharge. Such strategies
include:
• Using underground infiltration galleries to reduce or eliminate runoff while preserving the overlying site area
for green space and vehicular loading
• Harvesting and treating stormwater from roofs and other impervious surfaces for on-site use to reduce runoff
and potable water demand
• Using flow-through treatment systems in dense environments to capture spills, gross pollutants and trash
thereby protecting downstream soil and plants
• Targeting specific urban pollutants with subsurface filtration systems using optimized filter media
• Integrating compact high-rate biofiltration systems into the streetscape to provide pollution control
Table of Contents
• UrbanGreen® Solutions Staircase...............................................................................4
»» Managing stormwater close to the source
• Pitzer College – Claremont, California.......................................................................6
»» California college adds stormwater infiltration systems to help promote sustainability
• Oceano Apartments – Woodland Hills, California.......................................................7
»» Apartment complex meets LID goals with rainwater harvesting solution
• Salem-Keizer Public Schools – Salem, Oregon............................................................8
»» School district uses biofiltration to provide decentralized stormwater treatment
• Ocean Parks Boulevard – Santa Monica, California..................................................10
»» Complete “green street” reduces urban runoff discharges
• Huntington Library – San Marino, California............................................................12
»» Library’s cultural landscaping meets stormwater mitigation plan
• Mathei Place – Bellingham, Washington...................................................................14
»» High-density development takes on challenge of being green
• Lake Street in Whitehall – Whitehall, Michigan..........................................................16
»» Michigan’s first “green road” uses flow-through treatment to improve water quality
• Surfer’s Point – Ventura, California...........................................................................18
»» Managed retreat project provides long term solution to popular beach
• Point Breeze Office – Baltimore, Maryland................................................................19
»» Office building follows LID principles by integrating land based and structural BMP’s

Storing runoff, treating it and using it for irrigation, toilet
flushing, wash water, cooling make-up or other applications
turns stormwater into a valuable resource.
Biofiltration
Biofiltration is a compromise between LID practices
and traditional flow through BMPs. Filtration through
a deep media bed provides a high level of treatment and
some runoff reduction. Incorporating plants and organic
material into the mix further enhances performance. Because
biofiltration is a flow-through treatment process and does not
eliminate runoff completely, it is preferred when options higher
on the staircase are not practical.
Traditional Design –
Treatment Trains
Traditional stormwater criteria require
both improving the quality and
managing the quantity of runoff. One
of the best practices is to incorporate
pretreatment, detention and treatment
into an integrated system. The use of
detention and treatment systems in a
conventional design continues to provide
significant environmental benefits and
is acceptable in many jurisdictions. This
approach can meet TMDL requirements by
providing a high level of pollutant removal
and preventing erosion damage from
peak flows.
4 5
Surface Infiltration
Surface infiltration is the first option in many LID
strategies. Infiltrating runoff through engineered
soils cleans the water and slowly recharges groundwater
systems that supply aquifers, streams and lakes. Where
viable, infiltration is an effective means of managing
stormwater runoff because it often allows you to address
both water quality and water quantity concerns. Practices
include minimizing impervious surfaces (and using porous
hardscape), rain gardens and bioswales.
Subsurface Infiltration
For dense developments or sites with lower
infiltration rates, aboveground practices
may not be a viable solution. The next step to consider is
underground infiltration practices such as vaults, chambers
and pipes with open bottoms or perforations. Belowground
practices provide a significant storage volume and
infiltration footprint without using land that could otherwise
be developed or preserved.
Rainwater Harvesting
Harvesting runoff and using it on-site
provides many benefits beyond stormwater
management. Not only does harvesting reduce runoff
from the site, it preserves municipal fresh water supplies,
eliminates the energy required to move water long
distances and eliminates CO2 emissions associated with
that energy consumption.
Solutions Staircase
Low impact development regulations
direct us to manage stormwater close to
the source and mimic predevelopment
hydrology to the maximum extent
practicable. It is easy to meet those
goals by taking a systematic approach
to selecting which BMP is right for your
site. First, select the runoff reduction
practices that are most appropriate for
your site, paying particular attention to
pretreatment needs. If the entire design
storm cannot be infiltrated on-site,
select a treatment BMP for the balance.
Finally, select a detention system to
address any outstanding downstream
erosion issues.
hydrodynamic
separation
detention
filtration
retention
© 2012 Contech Engineered Solutions LLC

6 7
In 2001, Pitzer College reimagined its campus.
The college committed itself to expanding
in an environmentally responsible fashion.
The 2003 Housing Master Plan proposed
new residence halls designed with both
architectural flair and eco-friendly features.
Phase I of the project, Atherton Hall, was so
green it achieved LEED Gold certification.
For Phase II of the project, the construction of
Built in 2012, Oceano apartments is a 244 unit,
5.8 acre community located in Woodland Hills,
California, featuring outstanding architecture
and design as well as a host of the most
modern and cutting edge amenities. The goal
of the development was to provide residents
with a unique, sustainable environment and a
neighborhood feel.
Water and energy conserving technologies
and practices were incorporated into the site to
Pitzer College » Claremont, CA
Owner: Pitzer College
Engineer: KPFF
Landscape Architect: Mia Lehrer, Associates
Contractor: Bali Construction
Technical Description:
CMP Infiltration - 163 LF of 60-in. dia
ALT2, perforated CMP
Installation Date: June 2011
Oceano Warner Center »
Woodland Hills, CA
Owner: TDI Real Estate Holdings LLC Dune &
Real Estate Partners LP
Engineer: KHR Associates
Contractor: AR Pipeline
Technical Description: (3) CDS® hydrodynamic
separators; 88,000 gallon cistern made from
500’ of 96” diameter DuroMaxx® SRPE
the Mosbacher/Gartrell Center for Media Experimentation and Activism, the college set its goals even higher - LEED Platinum
certification. More than 40 sustainable features were incorporated into the design of the residence halls, including a green roof,
solar panels, permeable concrete, and a graywater system to collect and treat water to be used for irrigation. The project was a
way to celebrate rainfall, sustainability and create a seamless transition to the Outback portion of the campus.”
Contech helped the college meet its goal by providing two stormwater infiltration systems to capture runoff, storing the water
during a storm until it can be slowly released into the surrounding native soil and recharging the aquifer. Both systems use 60-in.
diameter ALT2, perforated corrugated metal pipe (CMP). The first system
uses 197 LF of CMP to store 5,684 cf of runoff while the second system
uses 126 LF to store 9,400 cf of runoff. The two systems were enclosed in
a non-woven geotextile to prevent clogging of the perforations.
“This was beyond green design. There was no storm drain infrastructure
on site; the underground detention was necessary for the project to move
forward,” said Omar Maciel, Engineer at KPFF. Infiltration is a common
Low Impact Development (LID) practice. By utilizing subsurface infiltration, space is preserved for development, runoff is reduced
or eliminated and groundwater recharge can occur. Contech CMP infiltration systems can be sized and shaped to meet site-specific
needs, and are available fully or partially perforated. CMP detention and infiltration systems are available in all AASHTO
M 36 types, with various coatings to achieve 75-100 year design service life. In 2012, Phase II of the project earned LEED Platinum
certification from the US Green Building Council.
reduce the community’s overall carbon footprint. This included
an UrbanGreen Rainwater Harvesting System from Contech
Engineered Solutions. The 3.57 acre site was challenging
because it consisted of 85% impervious surface and included
48,778 sq. ft. of landscaping. Engineers at KHR originally looked
at retention as a way to control stormwater, but upon further
review, rainwater harvesting was chosen as it provided the runoff
reduction required by the Community of Woodland Hills in the City of Los Angeles.
A Contech CDS hydrodynamic separator was used to pretreat runoff collected from the roofs, surface parking and associated drive
aisle, keeping organic material and other debris from damaging or clogging the system and to reduce maintance costs. The treated
water then flowed to a 188,000 gallon cistern made from 500’ of 96” DuroMaxx Steel Reinforced Polyethylene. DuroMaxx is an
ideal choice for rainwater harvesting cisterns as it is strong, lightweight, and can be made in diameters of up to 120”. Contech
provided all of the pumps and controls, providing a turn-key system from a single provider. Contech also provided KHR complete
sizing, engineering, and installation support.
The stormwater management design also called for two additonal CDS units to treat stormwater downstream, treating runoff from
roadways not collected in the cistern. The CDS system uses continuous deflective separation to effectively screen separates and trap
debris, sediment and oil from stormwater runoff.
Oceano Warner Center was honored as the Best New Construction in Los Angeles by the California Apartment Association and is
LEED Silver Certified.
The 2003 Housing Master Plan
proposed new residence halls
designed with both architectural
flair and eco-friendly features. Infiltration
The goal of the development was
to provide residents with a unique,
sustainable environment and a
RWH neighborhood feel.

8 9
Voters in the Salem-Keizer Public School District
passed a $242.1 million school construction
bond in 2008 — one of the largest in Oregon
history. This bond included increases to school
safety, renovations and upgrading of current
facilities, construction of four new facilities
to alleviate overcrowding, and independent
oversight of all bond-related projects.
An internal high-flow bypass weir is a standard
design feature of the UrbanGreen BioFilter.
This eliminates the extra high-flow bypass
inlet structure that would have been required
with alternative biofiltration products. This
configuration greatly reduced installation time
while providing additional cost savings to the
District. Activation of each BioFilter unit, plants
and even first-year maintenance to ensure
establishment of a healthy root system, are
all included in the purchase price, providing
additional cost savings.
Salem-Keizer Public Schools »
Salem, OR
Owner: Salem-Keizer Public Schools
Engineer: Youngman Locke Engineers
Contractor: Emery & Sons
22 UrbanGreen® BioFilters 4-ft x 6-ft
Installation Date: January 2011
The District created a construction bond campaign to share how the bond addressed these community concerns, and strengthen
community relationships. Two of the new schools, Straub Middle and Kalapuya Elementary, would benefit the community through
providing healthy and safe environments for educational programs, and providing access for West Salem neighborhoods, through
the planned extension of Wilmington Avenue. They were working within a tight time frame to complete construction and open the
new schools on schedule. As a result, a quick-installing solution that
addressed stormwater management was required. The District worked
with Youngman Locke Engineers to find a Low Impact Development
(LID) solution.
“The LID solution was desired because it decentralizes treatment,”
said Ron Hudkins, P.E., with Youngman Locke Engineers. “It also has
the additional benefit of lessening the peak water runoff volume.”
The Contech UrbanGreen® BioFilter was selected for the project
because it could provide a high level of treatment and partial reduction of runoff volume. The UrbanGreen BioFilter is a cost-effective
solution that is a compact, versatile and reliable alternative to conventional bioretention designs.
UrbanGreen Biofilters are commonly configured with a curb inlet, but in this case the road on which the Biofilters are being used
has slopes of up to 9%, so the engineers designed the units with catch basins in the street to ensure all runoff would be captured
in the systems and not just flow by.
“One site challenge was the hilly nature of the site,” said Hudkins. “Wilmington Avenue traversed the
entire elevation change of the site, leading to varying grades at the basin locations - from two to 9.5
percent. This called for a new design for the UrbanGreen BioFilter.”
Emery & Sons installed 22 of the 4-ft. by 6-ft. UrbanGreen BioFilters in just 6 weeks. Additionally, a
Corrugated Metal Pipe (CMP) detention system composed of 336 LF of 72-in. diameter, 16 gage,
Aluminized Type II CMP was used to create a system footprint of 24-ft. by 108-ft.
“We were pleased with the final outcome of the project,” said Jay Remy, Director of Communications and
Community Relations for the Salem-Keizer Public School District. “We have two new schools open, serving
more than 1,000 students per day in a great learning environment.”
The ribbon cutting and open house events at Kalapuya Elementary and Straub Middle schools were held in September 2011. More
than 1,000 students, parents and other community members attended these and 11 other events at schools throughout the District
following the extensive summer construction projects.
“The LID solution was desired because
it decentralizes treatment,” said Ron
Hudkins, P.E., with Youngman Locke
Engineers. “It also has the additional
benefit of lessening the peak water
runoff volume.”
Biofiltration

10 11
In 2008, at the request of the Santa Monica
community, a project was initiated to examine
the portion of Ocean Park Boulevard west of
Lincoln Boulevard to Neilson Way. The community
requested solutions to issues based on scale,
character, health, safety, sustainability, landscaping,
accessibility and circulation. After several years of
planning and collaboration between community
members, the City of Santa Monica and other local
“The CMP installed very smoothly,” stated Randy
Slane, Construction Manager with Arcadis, the
construction manager on the project. “Excel Paving
Company is a great contractor and installed the
large, 7’ diameter pipe and connected it with an
excavator in less than an hour, like clockwork.”
Throughout the project, a few challenges were
encountered, such as installation of the pipe in
Ocean Park Boulevard Green
Streets Project » Santa Monica,
CA
Owner: City of Santa Monica
Engineer: Kimley-Horn and Associates, Inc.
Contractor: Excel Paving Company
• 4 Basins of ChamberMaxx®
• 3 Basins of Corrugated Metal Pipe
Installation Date: April to June 2012
stakeholders construction for the Ocean Park Boulevard project began in December 2011 with a groundbreaking ceremony. From Neilson Way to
Lincoln Boulevard, Ocean Park Boulevard will be turned into a “Complete Green Street,” resulting in a better performing, enhanced streetscape that
is pedestrian and bicycle oriented, attractive and reduces urban runoff discharges
into the Santa Monica Bay.
Key elements of the project included: wider sidewalks, over 100 trees, improved
landscaping, a drip irrigation system, crosswalks, traffic signal improvements,
parkway/stormwater biofilter swales and infiltration areas, storm improvements and
more. While searching for a stormwater solution, the City and Kimley-Horn and
Associates, Inc, the engineer on the project, turned to Contech Engineered Solutions
for help. Both long-term clients, they knew Contech would provide a strong level of
expertise in stormwater and Low Impact Development (LID) engineering.
As a solution, Kimley-Horn chose to utilize four basins of ChamberMaxx® ranging from 945 CF to 4,590 CF of storage, two basins of 84” perforated
corrugated metal pipe (CMP) with approximately 4,000 and 10,000 CF of storage and one basin of 24” perforated CMP with approximately 250 CF
of storage. Ideal in a shallow footprint, the open-bottom plastic ChamberMaxx allows infiltration into surrounding soil, effectively achieving runoff
reduction requirements. By utilizing subsurface infiltration, space is preserved for development or green spaces above, runoff is reduced or eliminated
and groundwater recharge can occur. Furthermore, ChamberMaxx’s light weight allows for installation by hand, rather than by heavy equipment,
providing a green and economical solution.
tight spaces, utility conflicts and grade issues. Due to utilities buried in the area, it was imperative that the pipe size varied throughout the project in
order to meet the depth requirements. In addition, the footprint was extremely restricted so the width and length of each
pipe section was carefully considered. There were also concerns about corrosive soils in the area so, as a solution, the
CMP was coated with polymer.
At completion, the project included improvements to over a half mile of vehicular right of way, more than 6,000 linear
feet of sidewalks and the 4th Street overpass. The end result has benefited the Ocean Park neighborhood and the entire
Santa Monica community by providing a working model of sustainability, multi-modality and low-impact street design.
Ocean Park Boulevard will be turned
into a “Complete Green Street,”
resulting in a better performing,
enhanced streetscape that is ...
attractive and reduces urban runoff
discharges into the Santa Monica Bay.
Infiltration

12 13
The Huntington Library in San Marino
California is a private, nonprofit institution that
encourages research and promotes education
in the arts, humanities and botanical sciences.
The library is replacing the current 9,000
square-foot entrance with a new Education
and Visitor Center. The $60 million project
features 6.5 acres of new gardens and about
43,000 square feet of educational facilities
and visitor amenities.
After treatment, the runoff is directed to a below
ground infiltration system made from 310 LF
of pipe-arched 71” x 47” 10 GA Aluminized
Type II perforated pipe designed to provided
8,731 CF of storage; 5,606 CF from the pipe
and 3,125 CF from the stone. The system stores
runoff in the pipe and surrounding stone during
a storm until it can be slowly released into the
surrounding native soil.
Huntington Library » San
Marino, CA
Owner: Huntington Library
Engineer: Breen Engineering
Contractor: Kana Pipeline
Technical Description: CMP Infiltration - 310
LF of pipe-arched 71”x 47” 10 GA Aluminized
Type 2 perforated pipe and (2) CDS®
hydrodynamic separators
Installation Date: 2013
The new facility will provide much improved services for more than
550,000 visitors who come to The Huntington each year.
The new buildings are designed to be compatible with the formality,
scale and materials of the original 20th-century Beaux-Arts architecture
on the property. The landscaping will include gardens highlighting the
natural, agricultural and cultural landscape origins of the estate in a
Mediterranean plant palette.
Given the dense site and the need to comply with Los Angeles County
Standard Urban Storm Water Mitigation Plan (SUSMP), Breen Engineering selected a belowground infiltration system with
pretreatment from Contech Engineered Solutions to manage runoff from the site.
Water from the roof and other impervious surfaces is conveyed to two Contech CDS hydrodynamic separators. The CDS is a swirl
concentrator hybrid technology that provides continuous deflective separation – a combination of swirl concentration and patented
indirect screening – into a unique product. The indirect, self–cleaning screening capability of the system allows for 100% removal
of floatables and neutrally buoyant material, without binding. Pretreament with a CDS removes trash and solids debris to protect
infiltration beds from solids occlusion, protects outlet control structures, and isolates sediment into a single structure to provide
easy maintenance.
Pipe-arch was used instead of large diameter pipe because the site was very flat with limited depth.
Using pipe-arch allowed for a larger volume of storage per foot of pipe; maximizing storage and
minimizing the depth of the trench.
“Breen Engineering decided to use this particular system at Huntington because it provided a
concentrated treatment area for a large project acreage,” said Evan Fernandez, Civil Designer at
Breen Engineering. “Infiltration being the recommended and preferred method for storm water
treatment by MS4 Permittees, it gave us the option to use the CMP system. The CMP, along with the
CDS units, allowed the site to maintain the original layout the architects intended, as well as utilizing
the existing storm drain system in many areas to create a complex storm drain system that can
provide flood protection and treatment control.”
Installation of the stormwater management system was completed in the Fall of 2013. The new Education and Visitor Center is
scheduled to open in early 2015.
The landscaping will include gardens
highlighting the natural, agricultural and
cultural landscape origins of the estate in
a Mediterranean plant palette. Infiltration
HDS

Matthei Place » Bellingham, WA
Owner: City of Bellingham
Engineer: Chris Webb & Associates
Contractor: Callen Construction
Products Used: The Stormwater Managment
StormFilter® and CatchBasin StormFilter
configuration and CMP Detention (250 LF of
60-in. dia. corrugated metal pipe)
Installation Date: 2008
The City of Bellingham agreed to surplus the
land for the stormwater wet pond to the project
in exchange for an agreement to manage the
fire station’s stormwater for both water quality
and flow control indefinitely. The addition of
this land to the project site took the total project
site to just about an acre – approximately
42,000 sq. ft. This additional area allowed the
architect to lay out the project with more open
space and allowed the construction of a bike
barn to encourage non-car transportation.
To provide the required treatment for the off-site stormwater flows from the fire station, two CatchBasin StormFilters were selected.
To meet the detention requirements for the off-site flows and for the roof water from the on-site homes, a 60-in. diameter
corrugated metal pipe vault system was used. The new 12,000 sq. ft. on-site parking lot did not require any additional treatment
or flow control as it was designed to directly infiltrate.
The off-site flows are treated by two CatchBasin StormFilters. One is a single cartridge unit located off-site in the back parking lot
of the fire station. The second unit is located on-site and provides treatment for the large apron in front of the fire station and a
portion of Harris Avenue. Following treatment in the CatchBasin StormFilters, the stormwater flows are directed to an on-site vault
system of approximately 250 lf of 60-in. diameter corrugated metal pipe in three parallel pipes with a header. The flow from the
14 15
In Bellingham, Washington – as in many
communities in the Pacific Northwest and
across the United States – the number
of projects constructed utilizing green or
sustainable practices is increasing rapidly.
Often these projects utilize emerging
technologies and construction practices and,
without the economies of scale, these green
features can come with a cost premium. The
goal of this project is to take on the challenge
of being green and sustainable while also meeting affordable housing requirements. The Matthei Place project’s goal is to build
14 permanently affordable single family attached homes and 21 parking places on ½ of a city block in Bellingham’s south side.
The primary challenge for this project was to achieve a level of density that is much higher than the surrounding development.
The site for the project was ½ of a city block that was designated for use as affordable housing by the Bellingham City Council
following the construction of a new fire station on the other ½ of the block. The original size of the site dedicated to the project was
approximately 37,000 sq. ft. which included part of a vacated right of way. In order to maximize the size of the site to allow the 14
units and the required parking to be provided while maintaining some open space, additional land was needed.
When the fire station was built, about 5,000 sq. ft. of land on the project’s ½ of the block was used to provide stormwater treatment
and detention/flow control in a stormwater “wet pond”. A “wet pond” provides dead storage for stormwater treatment and live
storage controlled by an outlet structure for stormwater detention.
“At the level of density necessary to build this type of project, dedicating
that much space to a detention pond is just not an efficient use of
land,” said the project’s Civil Engineer. The engineer and the owner
approached the City of Bellingham with an offer that if the project
proved to provide the detention and stormwater treatment function
afforded by the existing “wet pond”, the city would have to allow the
land containing this pond to be added to the project.
To meet the project’s green goals and to take full advantage of the
infiltration capacity of the project’s sandy loam soils, a pervious
concrete pavement system was proposed for all new parking areas.
The goal of this project is to take
on the challenge of being green
and sustainable while also meeting
affordable housing requirements. Infiltration
roofs of the 14 homes is also directed to the vault where it combines with the off-site flows and is detained
prior to being released to the city’s stormwater system and ultimately into Padden Creek.
In summary, the use of the CatchBasin StormFilters and the corrugated metal vault system was part of a
system that incorporated the Low Impact Development (LID) strategy of pervious pavement which allowed
this project to meet its goals of affordability and sustainability. The efficient use of land in the dense urban
areas is important to allow development to occur where services exist and avoid sprawl.

Surfer’s Point » Ventura, CA
Owner: Surfers Point
Engineer: RRM Design Group
Contractor: Tierra Contracting, Inc. /C.A.
Rasmussen, Inc.
Product Used: The Stormwater Management
StormFilter®, 60 cartridges 8-ft. by 24-ft.
Installation Date: April 2011
Since two decades of problematic
flooding contributed to the erosion,
the project required Low Impact
Development (LID) features to capture
and filter stormwater runoff for flood
control and water quality improvement.
Since two decades of problematic flooding
contributed to the erosion, the project required
Low Impact Development (LID) features to
capture and filter stormwater runoff for flood
control and water quality improvement. The
StormFilter provided by Contech, working with
the other biofiltration methods, met all the LID
criteria.
16 17
For more than 20 years, challenging
stormwater conditions and continued erosion
have been a problem at Surfer’s Point, a
popular surf break near Santa Barbara. Beach
erosion, degraded water quality and flooding
issues have caused tremendous damage.
Coastal development, unsustainable water
management practices and runoff from urban
and agricultural areas further exacerbated the
problem.
A collaboration of community stakeholders from government,
businesses, non-profits and residents spent years debating options,
and eventually chose the innovative “managed retreat” — or shoreline
retreat — approach as their long-term solution to effectively manage
the stormwater and stall erosion.
The design of a rainwater-permeable parking lot and sustainable
stormwater filtration system were critical to the success of the Surfer’s
Point managed retreat project. To provide the highest possible quality
treatment of runoff water, the City of Ventura and consulting engineer
RRM Design Group, chose Contech to provide a StormFilter® stormwater management system to use in combination with
bioretention from a grass bioswale, “buried cobble” berm and vegetated sand dunes. This StormFilter system was designed to
remove trash, sediment, oil, nutrients and heavy metals from stormwater runoff at flow rates of up to two cubic feet — that’s 900
gallons — per minute.
In addition to being the most economical solution, managed treatment is also the best environmental solution because it
reestablishes a natural erosion buffer zone through redesign of the urban watersheds and environmental restoration of this
1,800-foot stretch of shoreline. To create this zone, the old rip-rap was replaced with a cobble-and-sand berm, a crumbling bike
trail was relocated more than 60 feet inland, and a sustainable quality stormwater management system was designed to provide
high-quality filtration near the new bike path and parking areas to treat stormwater runoff before discharge to the nearby Ventura
River estuary and the Pacific Ocean.
Filtration
Both the City of Ventura and RRM Design Group have years of experience working with the StormFilter
product. In addition to the quality of treatment provided, StormFilter also offers quick installation. In
this case, the Surfer’s Point StormFilter was installed in less than an hour from offload.
“It was critical to the success of the project that treatment of the stormwater satisfied the strict
requirements of both the California Coastal Commission and the Regional Water Quality Control
Board,” recalls Jerry Michael, RRM Design Group principal, who provided civil engineering services
for the project. “StormFilter provided the best solution to meet all of the agencies’ concerns, and was
easy to install.”
The newly renovated Surfer’s Point was engineered to appear natural, hiding the highly-sophisticated stormwater filtration and
treatment system, and managing the beachfront by acting as a barrier against further shoreline erosion.
This innovative managed retreat project is the first of its kind for the state of California. It is featured on the National Oceanic and
Atmospheric Administration (NOAA) website in “Shoreline Management” and is hailed as a model environmental approach to
coastline restoration and stabilization.

Lake Street in Whitehall »
Whitehall, MI
Owner: City of Whitehall
Engineer: Prein & Newhof
Contractor: Thompson Brothers
CDS® model 3030 hydrodynamic separator
Installation Date: August 2012
The city transformed 2,800 lf of
Lake Street from a traditional
paved roadway into a state-of-the-art
stormwater collection system. HDS
Point Breeze Office »
Baltimore, MD
Owner: Maryland Department of
Transportation
Products Used: The Stormwater
Management StormFilter®
Based on low impact development
(LID) principles, curbs and gutters were
eliminated and surface runoff from the
parking lot was treated close to the source. Filtration
18 19
White Lake is a major tributary to Lake
Michigan and an EPA Area of Concern (AOC).
Historic industrial pollution contaminated lake
bottom sediments, tainted fish and harmed
water. Government officials are now working
to reduce the volume of polluted stormwater
that drains off the land and into White Lake.
The City of Whitehall recently completed
Michigan’s first “Green Road.” The city
transformed 2,800 linear feet of Lake Street from a traditional paved
roadway into a state-of-the-art stormwater collection system. The system
uses pervious pavers, a Contech CDS hydrodynamic separator, rain
gardens and bioswales to capture and repeatedly filter stormwater
runoff from 60 acres of streets and industrial land near White Lake. The
Contech CDS unit plays a critical role in this unique stormwater system.
Runoff on Lake Street is diverted into a series of bioswales along both sides of the road. These direct runoff into several detention
zones lined with native trees and plants. Runoff then flows into the new wetland areas. Each of these steps is designed to filter the
runoff and encourage it to soak into the soil. Prior to the retrofit, runoff collected at industrial facilities east of Lake Street drained to
the street without treatment. A CDS system was installed to remove trash, debris and sediment from the industrial area flows prior
to treatment by BMPs within the green street. The system uses continuous deflective separation to effectively screen, separate and
trap debris, sediment and oil from stormwater runoff. This greatly improves the longevity of those systems and retains pollutants
where they will not come into contact with groundwater, soil or wildlife.
“The City of Whitehall is committed to being a leader in stormwater treatment,” says Jason Washler, Civil Engineer with Prein &
Newhof. “With the new system, stormwater is treated multiple times prior to its eventual discharge into White Lake. The treatment
methods include naturalized wetlands, bioretention, pervious pavers, and a hydrodynamic separator from Contech. White Lake
is expected to be delisted as an EPA Area of Concern in 2014 as a result of the efforts of many local stakeholders, including the
City of Whitehall.”
Because the road’s stormwater system is so environmentally friendly, this project will further the EPA’s goals to reduce the quantity
and improve the quality of stormwater entering White Lake.
The runoff from an office building parking lot
at the Maryland Department of Transportation
on Broening Highway, Baltimore, needed to
be managed. Due to the size of the site there
was inadequate space for a landscape-based
stormwater application that could encompass
the required water quality flow rate. The entire
drainage area is approximately ¼ acre making
it a very tight site.
There were various pollutants of concern in the runoff from the
parking lot, including trash and debris, sediments (fine, medium
and coarse), oil and heavy metals (Cu, Zn, Pb and Cd). The
engineer divided the drainage area into 3 sections. The individual
areas were elevated, and the runoff was conveyed by sheet flow
into 3 swales using parking blocks. The swales were designed to
capture and temporarily hold pretreatment and recharge volume.
The swales direct runoff into linear precast StormFilter units designed with 3 cartridges in a trench vault (10-ft. length and 3-ft. width)
to treat the remaining water quality flow. Each cartridge has a capacity of 15-gpm. The cartridges are equipped with CSF® leaf
media to remove sediments, oil, and metals typically found in urban runoff. When the runoff volume is greater than the volume of
the system, overflow is directed to a catch basin to drain through an outfall. The system provides the same function as a sand filter,
but provides the same level of treatment in a much smaller space.
The site designed was based on low impact development (LID) principles. Curbs and gutters were eliminated and surface runoff
from the parking lot was treated close to the source. The StormFilter provided appropriate treatment for overflow from the swales,
which eliminated standing water. This project is an example of how to integrate a structural BMP with a landscape-based BMP to
achieve the desired stormwater management goal and follow low impact development principals. Stormwater runoff is managed
close to its source using a multi-benefit natural feature system, in this case vegetated swales.
The StormFilter is used to provide polished effluent quality within a tight footprint, so the water quality flow from the design storm
was adequately treated. Meanwhile the integrated system was able to convey the peak flow, avoiding the potential problems (water
ponding, scouring) that can be associated with swales.

ENGINEERED SOLUTIONS
Enhancing LID eBook
Dig Deeper
Find all the information you need at www.ContechES.com, including
field and laboratory test results, approvals, brochures, design guides,
standard details and specifications within the product section of our site.
Quick Links
• Stormwater Solutions – www.conteches.com/stormwater
• Rainwater Harvesting Brochure – www.ContechES.com/rwh
• LID Application Guide – www.ContechES.com/lid
• Professional Development Articles – www.ContechES.com/pdh
Connect With Us
We're here to make your job easier – and that includes being able to
get in touch with us when you need to. Search for your local rep at
www.ContechES.com/ConnectWithContech
Start a Project
If you are ready to begin a project, contact your local representative
to get started. Or you can check out our design toolbox for all our
online resources at www.ContechES.com/designtoolbox
www.ContechES.com • 800-338-1122
©2014 Contech Engineered Solutions LLC
All rights reserved. Printed in USA.
NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS AN EXPRESSED WARRANTY OR AN IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE.
SEE THE CONTECH STANDARD CONDITIONS OF SALE (VIEWABLE AT www.contechES.com/COS) FOR MORE INFORMATION.
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Enhancing Low Impact Development Designs Using Manufactrured BMP's

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