Underground Stormwater Systems
Manage runoff below ground and keep valuable surface space available. Explore modular detention, infiltration, and water storage with GRAF EcoBloc and project support from BARR Plastics.
GRAF EcoBloc modular underground stormwater system
What is an underground stormwater system?
An underground stormwater system collects runoff and holds it beneath the surface. Depending on the site design, the water can infiltrate into surrounding soil, be released at a controlled rate, or be stored for later use.
The right approach depends on the site's drainage objectives, soil conditions, groundwater, loading, and local requirements.
Place stormwater storage below parking areas, landscaping, and other usable surfaces, subject to project specific structural and installation design.
What does your site need to do with runoff?
EcoBloc can be configured for different stormwater functions. Choose the application that matches your project.
Hold it, then release it
Temporarily store runoff during a storm and release it through a designed, controlled outlet.
Explore detention applications →Return it to the ground
Store runoff within a permeable system and allow it to infiltrate where site conditions permit.
Explore infiltration applications →Store it for reuse
Create an underground reservoir as part of a designed rainwater harvesting system.
Explore harvesting applications →Infiltration suitability and any storage for reuse must be evaluated as part of the complete site design.
Featured system / GRAF EcoBloc
Meet GRAF EcoBloc
Interconnected plastic modules form a below ground reservoir sized and arranged for the site's storage needs.
EcoBloc gives designers a modular approach to detention, infiltration, and harvesting, with component options for inspection access and project specific configurations.
- Modular layout
- High void storage
- Inspection access options
- Lightweight components
- Traffic area applications*
- System accessories
* Loading, cover, burial depth, and module selection require project specific engineering review.
Built around the site, not a fixed tank shape
Use the surface
Keep above ground areas available for other site functions.
Configure the footprint
Arrange modules around available dimensions and storage targets.
Plan for access
Include appropriate inspection and maintenance provisions in the design.
Match site loads
Select the module and installation detail for anticipated loading.
Move components efficiently
Modular elements simplify transport and handling on many sites.
Scale with demand
Size the reservoir to the required volume and available space.
How the system manages stormwater
The hydraulic path depends on your site's design and the application selected.
Collect
Runoff enters from drainage infrastructure.
Pretreat
Specified upstream measures help manage sediment and debris.
Store
Water enters the underground modular reservoir.
Manage
Water infiltrates, leaves through an outlet, or is held for reuse.
Maintain
Designed access points support inspection and upkeep.
From site constraints to a workable system
BARR Plastics supports engineers, developers, contractors, and municipalities with system selection, design assistance, supply, and installation guidance.
Share location, drainage objective, required volume, and project stage.
Consider footprint, depth, soil, groundwater, and loading.
Review module options, connections, access, and configuration.
Coordinate components and logistics with the project schedule.
EcoBloc product and design resources
Use these BARR resources to review the system, available components, design information, and project support.
Underground stormwater systems FAQ
What is the difference between detention and infiltration?
Detention temporarily stores runoff before a controlled release. Infiltration stores runoff while allowing it to soak into suitable surrounding soil. A site assessment and local requirements determine which approach fits.
Can EcoBloc be installed beneath a parking area?
EcoBloc has options for trafficked areas. The right module, cover depth, installation detail, and loading must be checked for each project.
Can an EcoBloc system be inspected?
Inspection access can be incorporated using compatible system components. Plan inspection and maintenance access during the design stage.
What does BARR need to review a project?
Start with the site location, intended application, target storage volume if known, available footprint, depth limits, loading requirements, project timeline, and any site plans or drawings.
Does BARR provide design and installation support?
Yes. BARR describes consultation, system selection, design assistance, product supply, and installation guidance for EcoBloc projects. Contact the team to confirm the scope needed for your site.
Planning an underground stormwater system?
Send BARR your project location, drainage objective, drawings, and required volume if available. The stormwater team can help you assess an EcoBloc configuration for your project.
Final system sizing, geotechnical suitability, loading, and compliance require project specific professional review.