As a functionally equivalent bioretention facility, Silva Cells are a great choice to maximize valuable surface area in heavily paved urban environments, given the system’s modularity and flexibility. Silva Cells perform biofiltration and bioinfiltration; the system can also provide temporary storage and peak flow reduction, but on a reduced scale (given that it’s primarily filled with soil).

Silva Cells Perform Underground Bioretention:

Biofiltration and Bioinfiltration

The Silva Cell system can be configured for biofiltration: moving stormwater through an underdrain to route it to designated sites along the stormwater sewer system. Likewise, Silva Cells can perform bioinfiltration in which it retains stormwater naturally in the ground by moving it to the trees.


The advantages of incorporating the Silva Cell system into a green infrastructure plan are numerous, including its proven track record of growing healthy trees, installation simplicity, and flexibility around existing underground utilities (and other project uncertainties). Its modular design also allows for easy access and excavation in cases of emergency. Other benefits include:

  • Improves water quality
  • Mitigates heat island effect
  • Reduces energy load
  • Peak overflow reduction
  • Little to no maintenance
  • May use any type of soil – even site-specific soil
  • Most efficient use of space within urban environment


As a bioretention BMP facility, the Silva Cell system is approved across North America. Some of its specific features that make the system an ideal fit in nearly any environment include:

  • Available in 1x, 2x, or 3x sizes to fit unique project needs
  • Open interior format for optimal soil volume, water, and root spread
  • Regionally manufactured in the US, Canada, and UK
  • Complimentary design and installation support from DeepRoot technical team

Silva Cell Installation Aerial and Section View

Want to learn more?
DeepRoot’s Silva Cell Fact Sheet resource is a detailed guide and sizing manual and is available for download today.

How it works

Meet regional stormwater requirements using underground bioretention designed for tight urban spaces. The Silva Cell is a stormwater BMP that leverages soil and trees to provide:

Water quality / pollutant control

Peak overflow reduction/flow control


Any type of soil

Grow big trees


The soil contained in the Silva Cell serves two important functions: growing large trees and treating stormwater onsite.

Interception and Evapotranspiration: Large trees intercept and evapotranspire significantly more rain than small trees. For example, a healthy 40 year old Hackberry tree is estimated to provide 14 times as much interception as a 10 year old Hackberry (McPherson et al 2006).

Long-Term Infiltration: As roots grow and then decay, they leave open channels in the soil that restore and/or enhance porosity and infiltration rates. Several studies have found a significant increase in saturated hydraulic conductivity in bioretention with plants as compared to those without (e.g. Lucas and Greenway 2011).

Water Quality Benefits: Vegetation is crucial to many water quality benefits, including removal or sequestration of dissolved nutrients, hydrocarbons, and Total Suspended Solids (TSS).

Plants also slow water flow, allowing more time for sedimentation to occur (Hunt et al 2012).

Silva Cell compared to typical bioretention systems

Unlike some bioretention systems, which leach nutrients and negatively impact receiving water bodies, Silva Cell systems also provide nutrient removal. Additional low impact development benefits of the system include:
– Water quality
– Peak overflow reduction
– Low/no maintenance
– May use any type of soil
– Efficient use of space

Silva Cells can be used on almost any type of site, including:
– Streets
– Plazas
– Parking areas
– Green roofs/on-structure
– “Break-out” zones.



U.S. Approvals
Canadian Approvals
City of North Vancouver
City of Calgary
City of Edmonton
Toronto Regional Conservation Authorityaccept Silva Cells as an equivalency for bioretention
Lake Simcoe Regional Conservation Authority accept Silva Cells as an equivalency for bioretention
Credit Valley Conservation Authorityaccept Silva Cells as an equivalency for bioretention
Province of Ontario: Ministry of the Environmentaccept Silva Cells as an equivalency for bioretention
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