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| Los Angeles River East |
The Pennypack Trust is partnered with four other watershed organizations in the
Philadelphia suburbs in a consortium that is working to improve water
quality and reduce stormwater quantity in the Delaware River. Our
consortium works in the Philadelphia suburbs, but the William Penn Foundation who spearheaded this work is funding seven similar consortia
throughout the huge watershed. Our consortium is tasked specifically
with reducing stormwater, while the consortia working in less-developed
parts of the basin are working to reduce agricultural impacts and to
preserve open space. The entire basin-wide project is called the Delaware River Watershed Initiative.
Our work
has been going on for 1-1/2 years now, and the staff of the foundation
requested a tour of sites where the foundation's support has been used
to implement stormwater management projects in the field. On Thursday,
August 6, the watershed organizations' and foundation's staff members
gathered for a day-long bus tour of four sites scattered throughout the
Philadelphia suburbs.
First stop was at a private residence in Haverford, Delaware County where a rain garden had been
installed. This rain garden was one of about 20 rain gardens that are
being installed in prominent locations where neighbors and passers-by
can become familiar with using a rain gardens to capture and infiltrate
stormwater running off impervious surfaces instead of allowing it to
pour directly into storm drains.
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| Publicity in the front yard |
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| The rain garden, planted in May |
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| Homeowner (blue shorts) and project consultants (right) |
Second stop was a detention basin created to manage the
stormwater for a 40-unit subdivision in Whitpain Township, Montgomery County. While the basin was larger than needed to manage
the stormwater generated by the subdivision, the basin was poorly
designed and actually did almost nothing to detain stormwater. The
municipality has committed to modifying the basin by reducing the
diameter of the discharge pipe (thus trapping and holding the stormwater
for longer periods of time), creating islands, peninsulas, and pools
within the basin to create habitat, and planting native vegetation
throughout.
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| On the berm above the basin (about 10 feet deep) |
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| Temple University hydrologist Lora Toran explaining testing equipment to monitor project effectiveness |
After
lunch, we toured a municipal sports complex in Horsham, Montgomery County where stormwater sheets off
playing fields. (Turf sheds
water almost as effectively as asphalt.) At this location, the
municipality intends to create deep, rock-filled swales planted with native grasses or plastic igloo-like underground voids that will allow
rainwater running off the fields an opportunity to soak into the ground
rather than run off to the adjacent creek.
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| Water from the playing fields (right) and parking lot pours into this swale, then directly into a creek |
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| Grass swale will be replaced with a rock-filled infiltration trench |
Later in
the afternoon, we stopped at one of the most challenging and
intractable sites imaginable; we wanted to show the foundation staff
members just what our organizations have to deal with in the developed
suburbs. Here in Abington, Montgomery County, the headwaters of Sandy Run drain a fully-developed
residential and retail neighborhood. Because the watershed has so much
impervious surface (e.g., driveways, rooftops, lawns, and roads), very
little rain water soaks into the ground, so the stream has almost no
baseflow during dry periods. However, when it rains, Sandy Run turns
into a raging torrent because all of the imperious surfaces shed water
directly to the creek. Unfortunately, this neighborhood is densely
developed, so the stream channel is located in residents' backyards and
there's nothing that can be done to widen the channel or create
stormwater detention. Instead, Abington confined the creek to a
concrete channel reminiscent of the infamous Los Angeles River to
sluice the water downstream as quickly and "safely" as possible.
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| Concrete confines |
During Hurricane Floyd, two people living downstream of this
channel drowned in their basement when the water rose up in a flash and
flooded the house. So much for safety.
Stormwater management is a difficult problem to address. It took us literally centuries to for our urbanized watersheds to become like are in today. Let's hope it doesn't take as long to correct the mistakes of the past.
