Technical Description:
(3) CDS® hydrodynamic separators
(3) DuroMaxx® SRPE cisterns
(3) Pump and controls systems
(3) Diversion manholes
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The Village at Westfield Topanga is a mixed-use project designed to be a community destination and gathering place in the heart of the West Valley. The project includes over one million square feet on 30.67 acres of under-utilized land within Warner Center. The Village features outdoor open spaces, pedestrian-friendly access to and amid the site, as well as bike lanes, transit stops and water features alongside a blend of new retail shops, restaurants, and offices.
All uses in The Village meet LEED certification standards. To meet the LEED requirements and the City of LA LID hierarchy, Fuscoe Engineering worked with Contech Engineered Solutions to design a series of stormwater quality best management practices including rainwater harvesting and reuse for irrigation.
Three UrbanGreen® Rainwater Harvesting Systems were designed to capture and reuse stormwater from roofs, parking lots, and other impervious surfaces, and use the water for irrigation. Each system uses a CDS® hydrodynamic separator to pretreat the captured water prior to entering the cisterns. CDS is an underground stormwater treatment device that uses swirl concentration and continuous deflective separation to screen, separate and trap trash, debris, sediment, and hydrocarbons from stormwater runoff. With CDS, there is no need for “first flush” diversion, so no water is wasted. Pretreatment is an essential component of rainwater harvesting, as it prevents organic material and other debris from damaging or clogging the system, and reduces maintenance costs.
The pretreated water is then stored in tanks made from DuroMaxx® Steel Reinforced Polyethylene (SRPE), a unique product made from eighty (80) ksi steel reinforcing ribs encased in pressure rated polyethylene (PE) resin. There was limited space for the cisterns, so Contech designed multi-barrel cisterns to fit the available footprint. There were also hydraulic limitations, so the design included the use of sump pumps to bring the water to the cisterns, and divertion manholes were used to divert high flows around the systems.
Pump and control packages were also provided, delivering 60 gpm at 85 psi to the drip irrigation systems. Providing completely integrated rainwater harvesting packages reduced the coordination between multiple vendors; improving the design, delivery, and installation for both the engineer and contractor.
System 1
- CDS 2025-5 – pretreating water prior to rainwater harvesting
- Diversion manhole to divert high flows around rainwater harvesting system
- Cistern: 402’ of 96” DuroMaxx – storing 146,348 gallons
- Pump and Control package – delivering 60 gpm at 85 psi to drip irrigation system
- Sump pump and control package – pumping stormwater to the cistern
System 2
- CDS 2020-5 – pretreating water prior to rainwater harvesting
- Diversion Manhole to divert high flows around rainwater harvesting system
- Cistern 2: 230’ of 96” DuroMaxx – storing 83,731 gallons
- Pump and Control package – delivering 60 gpm at 85 psi to drip irrigation system
- Sump pump and control package – pumping stormwater to the cistern
System 3
- CDS 2015-4 – pretreating water prior to rainwater harvesting
- Diversion Manhole to divert high flows around rainwater harvesting system
- Cistern 3: 151’ of 96” DuroMaxx – storing 54,971 gallons
- Pump and Control package – delivering 60 gpm at 85 psi to drip irrigation system
The three Contech UrbanGreen Rainwater Harvesting Systems provided a total of over 285,000 gallons to irrigate beautiful California drought tolerant landscaping.
"The stormwater quality design on The Village was incredibly involved, intricate, and interrelated," said Greg Mino, Senior Project Manager at Fuscoe Engineering. "We needed a strong partner to help execute the design and facilitate the installation of the various stormwater treatment BMP’s specified throughout the project site. Contech is always our “go-to” stormwater treatment BMP provider, as they consistently provide top notch leadership, responsiveness, creativity, and follow-through from the inception of a project all the way through commissioning."
Technical Description:
(3) CDS® hydrodynamic separators
(3) DuroMaxx® SRPE cisterns
(3) Pump and controls systems
(3) Diversion manholes
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