The objective of the retrofit project at Black Rock Park was to incorporate stormwater Best Management Practices (BMPs) into the expansion of facilities including a new police station and public works depot. Goals included the improvement of water quality and water resource conditions in the Schuylkill River as well as reduced downstream flooding. Implementation of this type of naturalized basin decreases maintenance costs for Upper Providence Township, beautifies the park, and provides educational opportunities in line with MS4 permit requirements. The basin at Black Rock Park has been certified as a Backyard Wildlife Habitat by the National Wildlife Federation because it provides a refuge for fauna.
The basin measures 3,600 square feet and was originally designed as a dry pond retention basin composed of turf grass to trap runoff from the adjacent paved areas. To naturalize the basins, native plant species were planted by volunteers led by the Delaware Valley RiverKeeper and local watershed groups. Tall growing native plants and soil absorb much more water and pollutants than normal sod. The rainwater from impervious surfaces is collected in the basin and is naturally filtered by the plants before being absorbed into aquifers and waterways. This BMP prevents flooding within Black Rock Park and helps mitigate the serious problem of downstream flooding in the Commonwealth.
To provide enhanced stormwater management for the site, the project partners implemented the following steps: Assessment of Area by the Delaware RiverKeeper Network, Implementation driven by community outreach efforts and partnerships, and a long-term Maintenance Plan.
Assessment of Area
Delaware Riverkeeper staff visited the Black Rock basin for an initial inspection on July 27, 2004. Analysis of the soils on the basin revealed silt loams and clay loams with gravel loams found on the embankments. The project area included turf, cold season grasses, some trees, and a small grove of trees to the east. Plants on the site were noted in order to pinpoint invasive species and plants one could expect to re-inhabit the area. The only invasive species in the inventory were full-sized tree-of-heaven (Ailanthus altissima) and their seedlings. Aggressive native species, common cattail (Typha latifolia) and summer grape (Vitis aestivalis) were also discovered in the basin. The plant inventory from the grove and the basin was analyzed to help formulate the list of equivalent native species to plant.
Work began on the site August 24, 2004 by volunteers orchestrated by the project partners. Cold season grasses and sod were removed and the basin was regraded. Native species had been chosen according to their tolerance of both moisture and salt from parking lot runoff. Two native seed mixes were sown, plugs of wild flowers and grasses were installed and native shrubs and trees were planted. To secure the seed mixes and to prevent erosion, a biodegradable blanket was placed on the basin’s steep areas. All of the basin’s bare soils were covered with a crop of winter wheat to establish plant life. For a bioretention diagram, please click here. For a plant list, please click here.
Monitoring the site is necessary for the project’s success. The maintenance plan accesses the basin’s continued ability to retain and filter stormwater runoff and the establishment of native plants. Initially the basins needed to be monitored to verify the establishment of preferred plants, but in the coming years only a bi-annual inspection by a professional should suffice.
Part of this project’s maintenance plan includes early detection and prevention of invasive species. The Delaware Riverkeeper prepared an invasive plant species report directed at managing this basin. Since tree-of-heaven was found during preliminary inventories, careful attention is paid to extracting this fast growing tree and the proliferation of seedlings it produces. Two other aggressive but native plants were found in the basin during the first inspection. These are common cattail (Typha latifolia) and summer grape (Vitis aestivalis). The most aggressive invasive plant to this date is multiflora rose.
Other maintenance activities include checking and clearing drains of debris and trash until the establishment of desirable plants. Reseeding can keep the area looking colorful. Planted shrubs and trees are regularly watered, pruned, mulched, tagged for visibility during mowing, and observed for disease. Mowing of the basin can occur on an annual basis and is recommended in the early springtime. In the first year after planting the basin it can be mowed to no less than six inches for a second time in July.
The township has financially benefited from the transformation of this basin. Naturalizing the basin relieves the township from costly maintenance work, like regular mowing.
Watershed: Schuylkill River
Black Rock Park is located at the intersection of routes 113 and 29 at 1286 Black Rock Rd. The Park is approximately 49 acres, surrounded by the township’s administrative buildings and police department office building and garage. The park also incorporates softball fields, basketball courts, a skate park, and other amenities.
Non Point Source Pollution Prevention Education Mini-grant from the Pennsylvania Association of Conservation Districts (PACD). Educational sign was $570. Plants cost $853.
Friends of the Mingo Creek
25 Iroquois Drive
Royersford, PA 19468
Upper Providence Township
1286 Black Rock Road
Oaks, PA 19456