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 Regional Project Profile
Delaware County Community
College
Stormwater Management Techniques
Category:
Implemented Retrofit Design
Type of BMP:
weir,
wet pond, infiltration beds, porous pavement, green roof
| Description |
Location |
Partners |
Cost
| Contact |
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Delaware County
Community College (DCCC)’s comprehensive plan to improve water quality
and environmental stability within the Crum Creek watershed aims at
upgrading aging stormwater management techniques in conjunction with the
construction of a new
Science Technology
Engineering Math (STEM) complex. The
new 132,000 square foot STEM complex at DCCC clarified the
need for bigger-scale stormwater Best Management Practices (BMPs) and that components of some 2005 improvements using Pennsylvania Department of Environmental Protection (PA
DEP) 2003 grants were deficient.
Components of the first
phase of the project known as the Martin's Run Headwaters project was completed in 2005 with Growing Greener grant
funds and included: 1) Raising the level of the wet pond and installation of a
check dam; 2) Pervious pavement with infiltration bed (now
demolished) and 3) Erosion control measures (now demolished). The
STEM complex to be completed by 2009 incorporates: 4) additional
infiltration beds and 5) green roof.
For a plant list
associated with the STEM complex improvements, please click
here. For a
corresponding layout of the planting scheme (also includes plant list),
click
here. For
a partial land development plan for the STEM complex including outlines
of infiltration beds and drainage, click
here, and for plan
outlying additional sitework at STEM, click
here.
1) Raising the level of the wet pond and installation of a check dam
In order to increase the
effectiveness of aging stormwater management techniques on campus, the
College upgraded a wet pond and sediment pond in 2005. The wet pond was
not holding enough water during storm events, while the sediment pond
was overloaded with sediment. A concrete and steel dam called a
“weir” was constructed to raise water levels about one foot in depth and
store additional volume within the wet pond to mitigate area flooding. More water is now treated before flowing into Martin’s Run, decreasing
downstream pollution and erosion. Raising the level of water within the
wet pond reduces the sediment load borne by the downstream sediment
pond, where the springhouse is found. This addition was a clear
alternative to dredging. The thick vegetative overgrowth in the
pond benefits the environment by absorbing pollutants. Invasive Phragmite, known as the Common Reed, retreated and no longer occupies
the center of the wet pond.
2) Porous pavement with infiltration bed (now demolished)
In 2005, a 3,164 square
foot porous parking lot and 3,076 square foot subsurface infiltration
bed were constructed at Delaware County Community College in front of
Employee Parking Lot #2. Best stormwater management techniques were
compatible with the features of the landscape, making it possible to
capture runoff from the sloping landscape. The stone subsurface
infiltration bed was constructed beneath the porous pavement. According
to estimates calculated by Cahill Associates, the infiltration bed
intercepted water from about 1.7 acres of paved parking area, but the
surface area could have been greater due to the tiered nature of the
lots. The drainage area for these BMPs was 26,229 square feet. The
College purchased a pavement vacuum device to clean the pervious
pavement more frequently than recommended. Since 2005 the porous
pavement and underlying infiltration bed have been replaced by newly
constructed infiltration beds, described in bullet #4.
3) Erosion control measures (now demolished)
An erosion control
blanket was installed to prevent erosion within the grass islands and in
adjacent wooded areas. Three-foot wide earthen berms were built between
stormwater beds to barricade water from flowing into the grass islands
and woods, carrying it instead towards inlets into the infiltration
system. The installation of earthen berms was less costly and
disruptive than a comparable solution entailing the creation of taller
curbs. On the other hand, the downside of earthen berms is that they
are vulnerable to erosion. These erosion control measures were
replaced by larger infiltration beds.
4) Additional infiltration beds
Infiltration beds have been added throughout the campus in conjunction
with the new STEM complex. Two have been added underneath a new parking
lot, and measure 54 feet x 100 feet x 39 inches, and 54 feet x 35 feet x
36 inches. There is also some newly created open space on campus, where
the pervious pavement and infiltration trench once stood. Underlying
this new green area is an enlarged infiltration bed. All of these
infiltration beds work similarly: runoff during storm events is
captured through inlets, through which stormwater is carried to the
infiltration bed to be stored and infiltrated to reduce surface
pollution and recharge groundwater aquifers. All these beds come
equipped with an overflow piping system that allows for excessive water
to drain off elsewhere. These infiltration beds are space efficient
since ground level facilities such as trenches or basins would need
additional room on the site.
An expansion of an
existing 1995 basin is also expected to be completed as well as yet
another infiltration bed, which should be installed beneath an existing
parking lot. These upgrades should be completed before the 2009 STEM
project deadline.
5) Green roof
The
STEM complex's green roof will be installed on the science building and
will include wild grasses planted on 2-3 feet of dirt. Architects are currently
working on the green roof design.
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County:
Delaware
Watershed: Crum
Creek
Delaware County Community College is found at 901 South Media Line Road
in Media, Pennsylvania. A
sub-watershed of Crum Creek known as Martin’s Run passes through campus
property. A 400-foot concrete swale directs stormwater runoff from
Route 252 onto campus, and then into a wet pond via a grass swale at the
upper end of campus. The sediment pond, where a small springhouse is
located, drains downstream into a large wet pond, which feeds into
Martin’s Run.
View
all
TVSSI BMPs in a larger map
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2005 project:
The porous pavement parking lot and infiltration bed cost an estimated
$31,722, or about $1,670 per parking space.
Weir (concrete/ steel dam) cost from $500 to $1,000 and was installed by
DCCC facilities staff.
Pennsylvania Department of Environmental Protection Growing Greener
Grant (2003): $50,000.
2009 project:
Currently unavailable. |
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Contact for 2005 project:
Daniel Wible, P.E. (project engineer)
Water Resources Engineer
Cahill Associates, Inc.
610-696-4150
dwible@thcahill.com
Contact for 2009 STEM compound project:
Tony DeLuca
Director of Facilities
Delaware County Community College
901 South Media Line Road
Media, PA 19063-1094
610-359-5110
TDELUCA@dccc.edu |
