Beneath the surface of the east parking lot at Diehl Park, Silva Cells aid in stormwater management.
Silva Cells
- Are modular plastic frames designed to support traffic loads, allowing for a suspended pavement in parking lotsand streets.
- Prevent soil from getting compacted around tree roots, allowing for large tree growth and on-site stormwater management.
- Make it possible to grow large canopy, mature trees within the confines of a parking lot.
In addition to helping cool and clean the air and provide beauty to the community, mature trees consume large volumes of water through soil storage, interception and evapotranspiration. A large quantity of planting soil provides ideal conditions for tree growth to occur and also provides storage for additional stormwater.

gallons of water annually. (USGS)
Trees provide an abundance of economic, social and environmental benefits. A city’s tree canopy can significantly reduce stormwater runoff and save millions of dollars in drainage infrastructure needs. A healthy level of urban tree canopy is around 40 percent. The City of Defiance is in the process of creating an inventory of existing street trees and subsequently developing a Master Planting Plan.
This combination of green infrastructure practices means that there is no longer a connection from Diehl Park into the combined sewer system.
This project was financed in part through a grant from the Ohio Environmental Protection Agency under the provisions of the Surface Water Improvement Fund.