The naturalized basin conversion project began in 2002. The project involved retrofitting six existing, mown grass stormwater detention basins into naturalized infiltration basins. The project naturalized five basins by the summer of 2003 and fully converted a sixth basin by the spring 2004.
The goals of the project included improved aesthetics, improved water quality, decreased stream temperature, increased groundwater infiltration, and a cost saving to the Township in the form of decreased mowing requirements.
In August 2002, contractors removed the low-flow channels in Basin 11. Then the area was seeded and covered with biodegradable matting. Volunteers planted trees and shrubs in early October 2002. In spring 2003, turf grass was eliminated through the application of a systemic, non-selective and non-residual herbicide. Meadow seed mixes were planted, which contained a variety of native grasses and wildflowers. Three separate mixes were used – a floodplain mix on the bottom, a showy upland mix on the side slopes, and a general detention basin mix throughout the basin. Approximately 600 plant plugs were also installed in the basin bottom and low-flow areas. One year after the conversion began, the naturalized basin exhibited vigorous growth. Sprouted wildflower seeds and plugs create a showy display.
To kick off the project, an educational brochure describing the benefits of naturalized stormwater basins was created and distributed. A series of public workshops at the Township Building informed homeowners living adjacent to the basins and other interested parties. In addition, informational signs installed at each basin upon completion inform the general public about the project.
Project results include the successful restoration of a traditional stormwater management basin to a more natural condition; the reduction of municipal maintenance requirements; a more aesthetically diverse landscape; and enhanced wildlife habitat. (Please note that water quality samples were taken but the results were inconclusive.) The basin will be monitored by a series of maintenance procedures developed with input from several sources, including landscape architects and land managers familiar with naturalized basins and the owner of a native plant nursery.
|Planting List for Basin 11|
|Quantity||Botanical Name||Common Name|
|16||Juniperus virginiana||Easter red cedar|
|15||Alnus serrulata||Smooth alder|
|15||Aronia arbutifolia||Red chokeberry|
|15||Cornus ammomum||Silky dogwood|
|5||Nyssa sylvatica||Black gum|
|5||Fraxinus pennsylvanica||Green ash|
|5||Acer rubrum||American red maple|
|5||Celtis occidentalis||Common hackberry|
|5||Betula nigra||River birch|
|100||Lobelia cardinalis||Cardinal flower|
|100||Asclepias incarnata||Swamp milkweed|
|100||Iris versicolor||Blue flag|
|100||Juncus effuses||Soft rush|
|100||Vernonia noveboracensisis||New York ironweed|
|100||Scirpus tabermontanii||Soft stem bulrush|
Watershed: Perkiomen Creek
Basin 11 is located within Lower Providence Township in Southeastern Pennsylvania. The 42,900 square foot pie-shaped detention basin runs along Stillmeadow Drive. A house is located close to each side of the lot while the lower back corner is wooded and contains delineated wetlands. The other back lot line runs along a hedgerow.
$98,795.00 (Total for all six basins)
Funded by a PA DEP Growing Greener Grant.
Perkiomen Watershed Conservancy
1 Skippack Pike
Schwenksville, PA 19473
Lower Providence Township
100 Parklane Drive
Eagleville, PA 19403