Yardley Borough is prone to flooding and local government officials have been taking steps to reduce the severity of the problem. Remediation is needed within the Borough because new area construction has created increased runoff during storm events, flooding out homes and businesses. In a healthy ecosystem, trees soften the blow of heavy showers, leaves and native vegetation absorb rain water, and water is naturally recharged to underground aquifers to replenish reserves. After considerable development in the region, high velocity runoff amasses from hard surfaces during downpours, resulting in habitual flooding. This project is one attempt to mitigate the hazardous floodwaters endured by this community.
In conjunction with site improvements at Buttonwood Park including a plaza, sidewalks, and parking, stormwater Best Management Practices (BMPs) were incorporated into the new design of the Park. Phases II and III of the redevelopment were completed in the fall of 2003 and the spring of 2004. The goal of this stormwater management system was to encourage the percolation of runoff instead of letting it contribute to the overburdened municipal rainwater conveyance facilities, which flood during peak flow storm events. The system detains surface water and eliminates pollution loading into nearby waterways.
Initially, porous pavement was planned to be installed, but percolation tests found that parking area soils were not suitable for pervious asphalt, though the roadway soils were. The plans for porous pavement were scrapped, and a subsurface stormwater collection system was instead installed.
This system is comprised of two excavated percolation pits installed with concrete vessels known as infiltration chambers, an infiltration trench, and a new conveyance system to pipe the water to these percolation pits. Surface water is directed towards inlets, where solid piping leads stormwater beneath the pavement into the infiltration chambers to effectively clean water before it is returned to the ground. The black drainage piping is hooked into the vessels, and the pits are backfilled with rock. The rock allows enough air to enter the infiltration pits for indigenous organisms to survive and perform bioremediation before the runoff recharges.
Native plants were installed on the site to provide additional cleansing and water retention performance, while also beautifying the site. The native plant list is available here, and a planting diagram can be found here. Bowman’s Hill Wildlife Preserve helped the Borough pick out native shrub and tree species for the park.
The infiltration chambers can be periodically pumped out to be cleared of sediment and debris. Inspection of the chambers is required on an annual basis.
Watershed: Delaware River
Buttonwood Park is found in the commercial center of Yardley Borough.
Buttonwood Park Committee
Bucher and James Inc. (project engineers)
Pennsylvania Department of Conservation and Natural Resources
Pennsylvania Department of Environmental Protection
Pennsylvania Department of Community and Economic Development
Bowman’s Hill Wildflower Preserve
The cost for all phases equaled about $750,000.
Pennsylvania Department of Environmental Protection Growing Greener Grant (2003) $20,000
Buttonwood Park Committee