Horsham Township / Hatboro-Horsham School District
Project Overview
We're exited about the opportunities to work with Horsham Township and the Horsham-Hatboro School District
to manage stormwater from this large multi-use site including Clearbrook Park and the Blair Mill Elementary
School. The site is well suited to the Project Headwaters approach, with three stormwater BMP projects already
identified in close proximity to one another.
Conceptual project designs for this site include "pocket wetlands" along a bioinfiltration swale, riparian buffer tree plantings, and improved stormwater management from the school parking area and roof downspouts.
visit Blair Mill Elementary School Home Page on the web
Constructed Wetlands and Bioinfiltration Swales- Clearbrook Park
The existing grassy sloped area in Clearbrook Park can be converted to biofiltration swales to provide water quality treatment.
In this conceptual plan, Water is temporarily retained behind a series of low check dams that span the swale in 50-100 foot increments. Water then filters through a planted layer of amended soil and a filter fabric into layer of clean run gravel. Depending on the porosity of the subsoils, water will either drain down gradient through the filter bed, which can be augmented with perforated drainage pipe to decrease travel time, or infiltrate into the subsoil.
Wetlands and swales can be planted with native wetland and meadow plants, attracting wildife and butterflies.
Stormwater / Roof Runoff Infiltration and Treatment
A rain garden was constructed at Blair Mill School in 2009. The rain garden was funded by PWD and designed by URS Corp. About 830ft2 of roof area drains to the 100ft2 rain garden, which is planted with native plants. The rain garden has a storage capacity of approximately 500 gallons, which is the equivalent of:
- 52 Dishwasher cycles
- 17 average (10min.) showers
- 324 low-flow toilet flushes
We are also investigating whether it is possible to provide additional infiltration and treatment of stormwater from the school parking area and additional roof runoff before it enters this small tributary.
Interested in building a rain garden on your own property? Download the Pennsylvania Rain Garden Guide (MB PDF), courtesy of The Wissahickon Watershed Partnership.
Riparian Plantings at Blair Mill Elementary School
The riparian zone directly adjacent to the school property is lacking a riparian buffer for approximately 500ft.
This area along the edge of the stream will be planted with native trees and shrubs to protect the small headwater stream on school property.
This buffer zone will absorb pollutants and nutrients that would otherwise end up running directly into the stream. Plant material slows runoff and filters out pollutants and sediments. Well-planted streamside buffers are also a great low-cost way to control erosion. While plants slow runoff, filter pollutants, and help control erosion, trees cast shade on the stream, cooling the water, reducing algae growth and improving fish habitat. A buffer with trees and shrubs also becomes a home to birds, butterflies and other creatures.
Educational Opportunities
Project Headwaters will encourage teachers to get their students outside and observe the local environment before and after the restoration activities are completed and make observations about changes that take place.
In one lesson, Students will observe their local surroundings and look for evidence of various types of point and non-point source pollution. Students also consider measures taken to reduce the effects of such pollution and devise methods to reduce the effects of pollution and stormwater runoff. Students use their knowledge of water pollution to complete a scavenger hunt.