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:
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:
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:
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).
POLLUTANT REMOVAL LEVELS
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:
– Parking areas
– Green roofs/on-structure
– “Break-out” zones.
SILVA CELL STORMWATER APPROVALS