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The Modular Wetlands Linear is the only biofiltration system to utilize patented horizontal flow, allowing for a smaller footprint, higher treatment capacity, and design versatility. It is also the only biofiltration system that can routinely be installed downstream of storage for additional volume control and treatment.
With numerous regulatory approvals, the system’s aesthetic appeal and superior pollutant removal make it the ideal solution for a wide range of stormwater applications, including urban development projects, commercial parking lots, residential streets, mixed-use developments, streetscapes, and more.
| Features | Benefits |
|---|---|
| Pretreatment chamber | Enhanced pollutant removal, faster maintenance |
|
Horizontal flow biofiltration |
Greater filter surface area |
|
Performance verified by both the WA DOE and NJ DEP |
Superior pollutant capture with confidence |
|
Built-in high-flow bypass |
Eliminates flooding and the need for a separate bypass structure |
|
Available in multiple configurations and sizes |
Flexibility to meet site-specific needs |
The Modular Wetlands Linear continues to outperform other treatment methods with superior pollutant removal for TSS, heavy metals, nutrients, and hydrocarbons. The Modular Wetlands® Linear is field-tested on numerous sites across the country and is proven to effectively remove pollutants through a combination of physical, chemical, and biological filtration processes.
| MEASURED POLLUTANT REMOVAL PERFORMANCE | |||
| Pollutant | Median Removal Efficiency | ||
| Total Suspended Solids (TSS) | 89% | ||
| Total Phosphorus (TP) | 61% | ||
| Total Nitrogen (TN) | 23% | ||
| Total Copper (TCu) | 50% | ||
| Dissolved Copper | 37% | ||
| Total Zinc (TZn) | 66% | ||
| Dissolved Zinc | 60% | ||
| Motor oil | 79% | ||
Some jurisdictions recognize higher rates - contact your Contech Stormwater Consultant for performance expectations.
The Modular Wetlands Linear has been evaluated by some of the most stringent stormwater technology evaluation organizations in North America, including, but limited to:
The Curb Inlet configuration accepts sheet flow through a curb opening and is commonly used along roadways and parking lots. It can be used in sump or flow-by conditions.
The Vault configuration can be used in end-of-the-line installations. Another benefit of the “pipe-in” design is the ability to install the system downstream of underground detention systems to meet water quality volume requirements, or for traffic-rated designs (no plants).
Modular Wetlands Linear is designed to drain down between storm events. To help vegetation remain healthy during extended dry periods or in arid climates, Contech recommends incorporating irrigation at the top of the system. Plant selection should also consider local climate, expected dry periods, and site-specific maintenance practices.
As stormwater enters the Modular Wetlands Linear, trash, debris, and other floatables are captured in the pretreatment chamber. In online configurations, peak flows can pass over the internal bypass weir, allowing high flows to bypass the treatment chamber. Where additional floatable control is required, a Connector Pipe Screen can be installed in the outlet bay in front of the outlet pipe. The screen captures trash and debris larger than 5 mm, such as plastic, bottles, and cigarette butts, while allowing stormwater to pass through to the outlet. High-flow bypass is not provided in end-to-end configurations.
Yes, the Modular Wetland Linear system can be used in arid/highland desert. In these cases, we recommend selecting drought-tolerant plants and including supplemental irrigation.
The minimum hydraulic drop depends on the design approach. For flow-based designs, the standard drop from inlet invert to outlet invert is 16 inches. Shallower drops may be considered on a project-specific basis. For volume-based designs with hydraulically connected upstream detention, a minimum of 6 inches of fall is required from inlet invert to outlet invert.
When Modular Wetlands Linear is installed downstream of detention, it can often be designed as a volume-based system that retains water and drains down over a designated period. Because the system can accept lower inlet pipes and build head within the unit, this approach may allow for a smaller unit size compared to a flow-based design. Final sizing depends on the applicable regulatory requirements and project-specific hydraulic conditions.
Modular Wetlands Linear can be sized using either a flow-based or volume-based design approach, depending on the applicable regulatory requirements and project conditions. Flow-based sizing is typically based on the required treatment flow rate, while volume-based sizing is based on capturing, retaining, and draining the required water quality volume over a designated period. Your local Contech Stormwater Consultant can help determine the appropriate sizing method for your project.
Yes. Modular Wetlands Linear can be designed with or without vegetation, depending on the project requirements and applicable regulatory approvals. In some applications, the system can also be installed underground. Because vegetation requirements may vary by jurisdiction or approval, the final configuration should be confirmed based on local regulatory requirements.
The Modular Wetlands Linear curb inlet configuration is designed to receive sheet flow through a curb opening and is commonly used along roadways, parking lots, and other paved areas. The vault, or pipe-in, configuration receives stormwater through a pipe connection and is typically used where runoff is collected and conveyed through a storm drain system.
Yes, the Modular Wetlands Linear system is available in various prefabricated sizes. The sizes available depend on the configuration (open planter, underground). Custom sizes may also be available.
Prefabricated sizes include:
4' x 4'
4' x 6'
4' x 8
4' x 13'
4' x 15'
4' x 17'
4' x 19'
4' x 21'
6' x 8'
8' x 8'
8' x 12'
8' x 16'
8' x 20'
8' x 24'
4' x 4'
These sizes provide flexibility to meet specific site constraints and installation requirements.
Modular Wetlands vaults are manufactured by an NPCA Certified Plant, or equal.
Yes, the Modular Wetlands Linear has California Water Resources Control Board, Full Capture Certification.
Yes, the Modular Wetlands system can be installed above grade. For these applications, it is recommended to use a cast-in-place vault.
The Modular Wetlands System can be placed both upstream and downstream of detention and sized using either a flow-based or volume-based design.
Contech provides installation guides, maintenance guides, and plant lists for the Modular Wetlands System. These guides can be found in our technical Documents Library by clicking here.
Pretreatment removes sediment, trash, and debris before runoff reaches the storage system, reducing pollutant loading on the Modular Wetlands media. This results in extended maintenance intervals and can extend the service life of the treatment train.
Flow-based sizing is determined by the project's water-quality flow rate and is typically used when the Modular Wetlands System is located upstream of a detention, storage, or infiltration system. Volume-based sizing is used when the Modular Wetlands System is located downstream of detention and is designed to treat the Water Quality Volume (WQV) over a specified drawdown period, typically 24 to 96 hours, depending on local requirements.
Volume-based treatment is often more cost-effective for projects with higher water-quality flow rates and where detention is already required for hydromodification management. By treating a controlled volume over time rather than a peak flow rate, the Modular Wetlands System can often be more economical than a comparable flow-based system.
Yes. The Modular Wetlands system is generally considered biofiltration, as it uses engineered media, vegetation, and physical, chemical, and biological treatment processes to remove pollutants from stormwater runoff.
Terminology can vary by jurisdiction. Some agencies may classify Modular Wetlands as a biofiltration system, biofilter, bioretention system, or manufactured treatment device, depending on local stormwater definitions and approval programs. Because definitions vary, designers should review the BMP terminology used by the local agency.
If you need clarification on the terms used in local regulations, please reach out to your Contech Stormwater Consultant.
Yes. When comparing pollutant removal data, Filterra has demonstrated performance that is generally consistent with or better than conventional bioretention systems for many common stormwater pollutants, and has been certified by the Washington State Department of Ecology for Basic (TSS), Phosphorus and Metals Treatment.
Based on information from the International Stormwater BMP Database, conventional biofilters may meet TAPE Basic Treatment requirements, but do not generally meet nutrient and dissolved metals performance levels.
Our team is ready to provide you with expert advice and assistance on local regulatory requirements, resulting in faster approvals.
Our engineers can review your requirements, weigh all options, and recommend the optimal solution to integrate with your site designs.
Our engineers can assist by providing product specific engineering calculations such as hydraulics, buoyancy, foundation reactions, and unit sizing.
We can quickly provide engineer’s cost
estimates to assist with your solution
selection process.
Our engineers can provide site-specific drawings for proposals, project meetings, and submittals, helping you be more efficient with your time.
Contractors know time is money, so we provide preconstruction meetings, delivery coordination, and on-site installation support to ensure a timely, smooth installation.
