During a recent expansion of Perkiomen Valley High School, stormwater Best Management Practices (BMPs) were incorporated into plans in order to manage the runoff from 28 acres of athletic fields and impervious surfaces. Components of the plan included: Vegetative Swales, a Wet Pond, Aerator, and Aquatic Bench, and a Maintenance Plan. The full list of plantings, including seed mixes, plugs, shrubs, and trees is available by clicking here.
The vegetated swales are composed of a mix of meadow grasses that accommodate runoff from the school’s 28 acres of athletic fields and impervious surfaces. Because stormwater naturally flows to this recessed and sloped area, the swales funnel the water down to the wet pond, making for cleaner and calmer runoff.
Wet Pond, Aerator, and Aquatic Bench
The wet pond collects water from the vegetated swales which carry runoff from athletic fields and parking areas. The property’s soils were not very penetrable to percolation and thus the decision was made to allow for a pond instead of a naturalized basin. The pollutants and sediment from the surrounding area gravitate towards the bottom of the deep wet pond and can be removed as needed. An aerator is used to oxygenate the pond’s water enough to sustain organisms like plants and aquatic life.
The aquatic bench was formed by removing the 12’ portion of top soil was removed and keeping it safely aside. The depth of the bed needed to be dug a foot deeper than anticipated to re-deposit the topsoil. This was done in order to maintain the ecological integrity of the site. Straw mulch was used to immediately stabilize disrupted areas. Warning flags were posted along the aquatic bench and a goose fence was mounted along the shoreline. The goose fence needed to circle the pond with stakes installed at 10-foot intervals, and the circumference was staggered with another subsequent row to effectively keep out the birds. Click here for a detail drawing of an aquatic bench by Cahill Associates.
A maintenance plan was implemented to include habitual mulching, pest control, weeding, pruning, etc. Even though a natural spring area on the wet-pond’s steep slope was carefully planted to avoid the invasion of cattails, by winter 2007-2008 they had grown in. The cattails are pulled out by hand to keep them from taking over. The District saves about $100 per month by not mowing their basins.
The BMPs are used as living laboratories, frequented by science classes learning about environmental issues. This project is not only indicative of Perkiomen Valley School District’s dedication to sustainable land-use, but it also stresses the District’s commitment to hands-on education: the students play an active role in the monitoring of the site. The naturalized sites are tested for chemicals, pH, temperature, dissolved oxygen and species diversity.
Watershed: Perkiomen Creek
Perkiomen Valley High School is located at 509 Gravel Pike (Rt. 29) two miles north of Collegeville in Montgomery County. The school property sits adjacent to Perkiomen Creek.
KCBA (landscape architects) cost approximately $3,200.
Aerator pump operations cost approximately $150 per month.
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