Mission - To advance the evolving field of sustainable stormwater management and to foster the
development of public and private partnerships.
Since the early 1990’s the field of stormwater management has undergone a dramatic shift from
a myopic flood-prevention approach to a more sustainable view that embraces both water quality
and quantity. A new suite of mitigation measures termed Stormwater Control Measures (also
known as Best Management Practices) was developed to treat various forms of urban stormwater
impacts including pollution, runoff volume and erosive flows. Recognizing the need for research
and public education, the Villanova Urban Stormwater Partnership (VUSP) was launched in
2002 as the product of a partnership between the Pennsylvania Department of Environmental
Protection (PADEP), private industry, and Villanova University’s (VU) Department of Civil and
Environmental Engineering.
The VUSP’s Stormwater Control Measure (SCM) Research and Demonstration Park includes
several types of SCMs to include a stormwater wetland, bio-infiltration and bio-retention rain
gardens and swales, pervious concrete / porous asphalt installations, infiltration trenches, and a
green roof. In the Fall of 2009, the VUSP also became one of the five research clusters that
constitute the Villanova Center for the Advancement of Sustainability in Engineering (VCASE).
The goals of VU’s SCM Research and Demonstration Park are to:
1) Improve our understanding of nonpoint source pollution
2) Scientifically evaluate the effectiveness of watershed technologies designed to control
nonpoint source pollution
3) Export our results and lessons learned to the stormwater community.
Educational signage has been installed at each SCM site to enhance the learning experience and
a website has been created to facilitate technology transfer. The experiences gained through the
construction, operation, monitoring, and evaluation of these sites form the basis for the outreach
and education component of the Research and Demonstration Park.
Details for each SCM can be viewed through the following link: http://www.villanova.edu/vusp.
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VU Bioinfiltration Rain Garden SCM (2007)
This bio-infiltration SCM was constructed in 2001 and its construction was funded by a PA
Growing Greener Grant. Additional research at the site has been funded by PA DEP Growing
Greener, PA DEP 319 Program, and PA DEP Coastal Zone Management Program. It was created
by retrofitting an existing traffic island on VU’s campus. The facility intercepts runoff from a
highly impervious (50%) student parking area and road (0.53 ha) that was previously collected
by inlets and delivered through culverts to a dry detention basin. It is designed to control runoff
from smaller storms through capture and infiltration of the first flush within the bowl and soil
void space storage. The bowl is approximately 18 inches deep, has a recession rate of
approximately 0.75 to 0.9 cm/hr with an approximate ratio of impervious to infiltrating surface
of 12 to 1. There is no underdrain. Maintenance consists of trash removal, invasive species
control, and yearly harvesting / composting the grasses.
Evapotranspiration and infiltration are responsible for capturing 100% of storm events less than a
½ inch (1.27 cm) and 97% of those between ½ and 1 inch. Water quality studies have shown that
nitrogen and other parameters such as phosphorous and metals are significantly reduced, and that
subsurface groundwater mounding is limited and temporary.
Lee, R., Traver, R., Welker A. (2013) “Continuous Modeling of Bioinfiltration Stormwater
Control Measures using Green and Ampt.” Journal of Irrigation and Drainage Engineering
(in press).
Flynn, K., Traver, R. (2013). “Green Infrastructure Life Cycle Assessment: A Bio-Infiltration
Case Study.” Journal of Ecological Engineering, Volume 55, pp 9-22.
Welker, A., Mandarano, L., Greising, K., and Mastrocola, K. (2013). “Application of a
Monitoring Plan for Stormwater Control Measures in the Philadelphia Region.” Journal of
Environmental Engineering, in press.
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Komlos, J. and Traver, R.G. (2012). "Long Term Orthophosphate Removal in a Field-Scale
Stormwater Bioinfiltration Raingarden." Journal of Environmental Engineering, 138, 991998. Link
Hunt, W.F., Davis, A.P., and Traver, R.G. (2012). “Meeting Hydrologic and Water Quality
Goals through Targeted Bioretention Design.” Journal Environmental Engineering, ASCE.,
138(6), 698-707.
Davis, A.P., Traver, R.G., Hunt, W.F., Brown, R.A., Lee, R. and Olszewski, J.M. (2012).
“Hydrologic Performance of Bioretention Stormwater Control Measures.” Journal of
Hydrologic Engineering, 17(5), 604-614.
Machusick, M., Welker, A., and Traver, R. (2011) “Groundwater Mounding at a Storm-Water
Infiltration BMP,” Journal of Irrigation and Drainage Engineering, Vol. 137, No. 3, pp. 154160.
Gilbert Jenkins, J.K., Wadzuk, B.M. and Welker, A.L. (2010) “Fines Accumulation and
Distribution in a Stormwater Rain Garden Nine Years Post Construction,” Journal of
Irrigation and Drainage Engineering, Vol. 136 (12), pp. 862-869.
Emerson, C. and Traver, R. (2008). “Multiyear and Seasonal Variation of Infiltration from
Storm-Water Best Management Practices.” Journal of Irrigation and Drainage Engineering,
134, SPECIAL ISSUE: Urban Storm-Water Management, 598–605.
Heasom, W., Traver, R.G., and Welker A. (2006) “Hydrologic Modeling of a Bioinfiltration Best
Management Practice Using HEC-HMS.” Journal of the American Water Resources
Association, Vol. 42, No. 5, pp. 1329-1347.
3
Stormwater Wetland (Adapted from Google Earth, 2011)
In 1998, an existing stormwater detention basin on VU’s campus was converted into an extended
detention wetland SCM, and was rebuilt during 2010. This SCM is currently funded by the EPA
Section 319 grant. Currently (2013) the site has had adequate vegetation growth over the past
two years and other species (flora and fauna) have moved into the ecosystem. The 0.8 acre CSW
treats runoff from a 41 acre watershed that includes at least 16 acres of impervious surface. The
watershed includes students’ residence halls, classroom buildings, parking, roads and a railroad.
The contributing watershed forms the headwaters of a watershed listed as medium priority on the
degraded watershed list, and treats flows that impacts a high priority stream segment on the
303(d) list.
The project has been published as an EPA 319 Success Stories Part III. This site was
reintroduced as a 319 NPS project in May 2011. Baseflow and water quality and quantity studies
are ongoing.
Jones, G.D. and Wadzuk, B. (2013). “ Predicting performance for constructed storm water
wetlands.” Journal of Hydraulic Engineering, 10.1061/(ASCE)HY.1943-7900.0000767
Wadzuk, B. M., Rea, M., Woodruff, G., Flynn, K. and Traver, R. G. (2010). “Water-Quality
Performance of a Constructed Stormwater Wetland for All Flow Conditions.” Journal of the
American Water Resources Association, 46(2), 385–394.
4
VU Infiltration Trench (2005)
The infiltration trench was constructed in August 2004 and is funded by the EPA Section 319
grant. This SCM has a very large ratio of drainage area to infiltration area to stress its capacity. It
is designed to capture approximately the first 0.6 cm of runoff from an elevated parking deck
(0.16 ha) and infiltrate it through a rock bed into the ground. The rock bed has a surface area of
approximately 7.2 m2, and is 3 m deep (under the influent box and picnic table in Fig. 3).
Overflow from the trench first exits through a pipe at the surface to the inlet pictured (far left of
Figure 3). During extreme events, if the overflow pipe is full, any additional runoff exits through
the porous pavers placed above the infiltration trench. Of the demonstration sites under study,
this site is the only one with a 100% impervious drainage area. Study of the site has revealed that
the bottom of the infiltration bed clogged during the third year, and all infiltration currently exits
through the sides. The drainage area receives continuous use by faculty and staff vehicles.
Emerson, C. H., Wadzuk, B. M. and Traver, R. G. (2010). “Hydraulic evolution and total
suspended solids capture of an infiltration trench.” Hydrological Processes, 24(8), 1008–
1014.
Batroney, T., Wadzuk, B., Traver, R. (2010). “A Parking Deck's First Flush” ASCE Journal of
Hydrologic Engineering, 15(2), 123–128.
Emerson, C. and Traver, R. (2008). “Multiyear and Seasonal Variation of Infiltration from
Storm-Water Best Management Practices.” Journal of Irrigation and Drainage Engineering,
134, SPECIAL ISSUE: Urban Storm-Water Management, 598–605.
http://www.stormh2o.com/SW/Articles/Constructing_an_Infiltration_Trench_Retrofit_BMP_16
689.aspx
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VU Pervious Concrete / Porous Asphalt (2007)
The PCPA SCM was constructed in October 2007. Its construction was funded by Prince
George’s County (EPA), RMC Foundation, and PA DEP. Additional studies have been
supported by PA DEP EPA 319 funding. The site, formerly a standard asphalt paved area, is
located behind Mendel Hall at VU campus. This SCM consists of an infiltration bed overlain by
a 15.2 x 9.1 m pervious concrete surface and an adjacent, equally sized porous asphalt surface. It
captures runoff from a campus parking area, passes the flow through either the pervious concrete
or porous asphalt surface course, and infiltrates it through a rock bed into the ground. The site
receives continuous use by faculty and staff vehicles. The site is designed to capture and
infiltrate storms of up to 5 cm of rainfall. From these events there is no runoff from the site. The
base of the infiltration beds are level and range from 0.9 to 1.5 m deep and are filled with washed
stone, with approximately 40% void space. In extreme events, when the capacity of the storage
beds is exceeded, flows are permitted to exit the site and flow out to the original storm sewer
system. This overflow eventually makes its way to the SWW. A vacuum street sweeper is used
two / three times of year for maintenance.
Welker, A., McCarthy, L., Gilbert Jenkins, J.K, and Nemirovsky, E. (2013). “Examination of
the Material Found in the Pore Spaces of Two Permeable Pavements,” Journal of Irrigation
and Drainage Engineering, Vol. 139, No. 4, pp. 278-284.
Nemirovsky, E., Welker, A., and Lee, R. (2013). “Quantifying Evaporation from Pervious
Concrete Systems: Methodology and Hydrologic Perspective,” Journal of Irrigation and
Drainage Engineering, Vol. 139, No. 4, pp. 271-277.
Welker, A., Barbis, J., and Jeffers, P. (2012). “A Side-by-Side Comparison of Pervious Concrete
and Porous Asphalt,” Journal of the American Water Resources Association, Vol. 148, No. 4,
pp. 809-819.
6
a.
b.
Fig. a. Linear SCM
Fig. b. Aerial View of the Treatment Train (Adapted from Google Earth)
The design and construction of the treatment train at VU’s campus took place during the Fall of
2011 and was funded through PADEP Growing Greener Grant. It includes a vegetated swale,
followed by two rain gardens in series, and finally an infiltration trench. This SCM is designed to
capture 1 inch storm event.
The swale and rain gardens act as pretreatment to the infiltration trench so that less flow annually
reaches the infiltration trench and there is a lower sediment load to preserve the infiltration
capacity over a longer design life. The aerial photo (Fig. b.) displays the collection area and
layout of the SCMs. The swale, rain gardens, and infiltration trench are noted by the green,
yellow, and red arrows, respectively. The six monitoring and sample collection sites are
represented by white arrows and are used to analyze water-quality and -quantity changes
throughout storm events.
http://www.stormh2o.com/SW/Articles/Applying_Stormwater_Control_Measures_in_Series_19310.aspx
7
Fedigan Rain Gardens
The Fedigan Rain Gardens constructed in 2009 include a Bio-infiltration and Bio-retention SCM
that captures runoff from the rooftop. The rain gardens were constructed as part of a joint project
with the university to create a green dorm. Recently, funding was secured from PA DEP
Growing Greener to study this rain garden as well as several others on campus.
Stormwater from the roof is diverted into the two rain gardens in front of the building. The bioretention site is lined to prevent percolation, with an underdrain while the bio-infiltration site has
no underdrain or liner. The east rain garden (Bio-retention) detains the water and releases it back
into the atmosphere through evapotranspiration, and slow release through the underdrain. The
west rain garden (bio-infiltration) utilizes both evapotranspiration and infiltration. Bio-retention
and Bio-infiltration is accomplished by using a combination of porous soils and vegetation. Both
the sites have media consisting of a 2.5-foot modified sandy soil. The species of vegetation
planted at the site can survive in both dry and wet conditions.
8
Fig. a. Green Roof at CEER, VU.
Fig. b. Cross section of the layers present in a typical green roof.
The design of the green roof (GR) was a retrofit of a small portion of VU’s Center for
Engineering Education Research (CEER) roof. The construction took place in 3 days in the
summer of 2006 and covers approximately 530 ft2. The site was designed to capture and retain
the first half inch of every precipitation event, thereby reducing downstream stormwater
volumes, stream bank erosion, and non-point source pollution. It has been found that the GR
outperforms the design, owing a great deal of the performance to evapotranspiration between
storm events. The GR will also protect the underlying roof material by eliminating exposure to
the sun’s ultraviolet (UV) radiation and extreme daily temperature fluctuations. A cross section
of the layers present in a typical green roof can be seen in Figure b.
Wadzuk, B., Schneider, D., Feller, M., and Traver, R. (2013). "Evapotranspiration from a Green
Roof Stormwater Control Measure." Journal of Irrigation Drainage Engineering,
10.1061/(ASCE)IR.1943-4774.0000643
9
Rain Gardens (Adapted from Google Earth)
The West Campus Rain Gardens project was funded by the America Recovery Act – PennVest.
The purpose of this SCM is to reduce the effective impervious surface draining to the Darby
watershed through disconnection of currently directly connected downspouts using rain gardens.
Over 70000 cf. of water is estimated to be removed from the overflow per year.
The rain gardens are designed to capture half inch of rain off the roof top with outflow going to a
raingarden. Overflow for larger storms will be through overflow of a small berm and then out to
preexisting catch basins in the lawn area.
10
Upper
Bed
Middle Bed
b.
a.
Lower Bed
Fig. a. Completion of bed construction by covering with choker stone prior to pouring of the pervious concrete
Fig. b. Pervious pavers
An infiltration SCM utilizing permeable pavement was constructed during the retrofit of an
existing paved area in the center of the campus of VU in August 2002. The contributing
watershed area is approximately 50,000 ft2 and is highly impervious, consisting of pedestrian
walkways, rooftops and some grassed areas. The rooftops and some adjacent paved areas are
directly connected to three separate rock storage beds (four feet deep) that are outlined by the
porous surface layer (Fig. a). The rock beds are linked through piping systems to distribute the
runoff between beds and allow for overflow during major storm events. The site was designed to
capture and infiltrate the first two inches of runoff, thereby reducing downstream stormwater
volumes, stream bank erosion, and non-point source pollution.
The first surface (2002) was entirely pervious concrete, however, this pavement did not perform
well and in October of 2004, approximately 40% of the pervious concrete was replaced with new
pervious concrete. In 2012, the repaired pervious concrete had significantly deteriorated and this
layer was replaced with pervious pavers (Fig. b). It should be noted that the more recent pervious
concrete site on campus built with updated material procedures has performed well. These
pavers have been strategically placed as to allow infiltration of rain water between them and into
the underlying rock beds. The functionality of this site in terms of water quantity and water
quality is expected to remain unchanged as the pervious layer serves mostly as a means to
transport runoff into the rock beds, with the rock beds themselves serving as the primary
mechanism of stormwater control.
11
Radlinska, A., Welker, A., Greising, K., Campbell, B., and Littlewood, D. (2012). “Long-Term
Field Performance of Pervious Concrete Pavement,” Advances in Civil Engineering, Vol.
2012, ID no. 380795, 9 p.
Horst, M., Welker, A., and Traver, R. (2011) “Multiyear Performance of a Pervious Concrete
Infiltration Basin BMP,” Journal of Irrigation and Drainage Engineering, Vol. 137, No. 6,
pp. 352-358.
Emerson, C. and Traver, R. (2008). “Multiyear and Seasonal Variation of Infiltration from
Storm-Water Best Management Practices.” Journal of Irrigation and Drainage, 134,
SPECIAL ISSUE: Urban Storm-Water Management, 598–605.
Kwiatkowski, M, Welker, A., Traver, R., Vanacore, M., Ladd, T. (2007). “Evaluation of an
Infiltration Best Management Practice (BMP) Utilizing Pervious Concrete”, Journal of the
American Water Resources Association, Vol. 43, No. 5, pp. 1208-1222
Braga, A., Horst, M., Traver, R. (2007). “Temperature Effects on the Infiltration Rate through an
Infiltration Basin BMP”, Journal of Irrigation and Drainage, 133(6), 593–601.
12
Rain garden microcosms used to study evapotranspiration. In-situ photograph shown in (a)
and new soil media configuration shown in (b).
Funding: PADEP Growing Greener 2008, 2011
Constructed: Original configuration, 2009; newer configuration, Summer 2013
Description: Weighing lysimeters are instruments that measure ET by utilizing a mass
balance analysis. The change in weight of the entire lysimeter system is equal to what comes
in due to precipitation minus what leaves the system through water draining out of the
lysimeter or through ET. Weighing lysimeters were designed to create a microcosm for each
of the SCMs studied, with inflows and outflows controlled and measured (Figure above).
Location: These microcosms are located on the top berm of the constructed stormwater
wetland.
Quick Facts:
-
The original BRG weighing lysimeter (Figure a) was created using a 0.76 m diameter and
0.91 m deep weighing bucket with the same soil mixtures and plants as the BRG on
campus.
13
-
The buckets are mounted on a tension load cell to measure weight over time with high
accuracy. The Sentran S-Beam tension load cell has a combined error of 0.025% of the
rated output compared to the 0.03% of the rated output given for the comparable
compression model. For example, with a weight measurement of 680 kg this difference
becomes significant, especially when tracking ET fluctuations in weight as small as 2 or
3 mm of water per day, which is equivalent to 0.91 to 1.36 kg in this lysimeter.
-
Total rainfall, percolation through the bucket (i.e. infiltration), relative humidity, solar
radiation, temperature, and wind speed were measured and recorded by a Campbell
Scientific CR1000 datalogger located roughly 4.5 m from the weighing lysimeter.
-
The new configuration of the weighing lysimeters is shown in Figure b and was
constructed in Summer of 2013.
14
Funding: PADEP Growing Greener 2008
Constructed: greenhouse set-up, summer 2011; relocated to outdoor site, summer 2012
Description: The constructed stormwater wetland is mimicked in a non-weighing lysimeter to
directly measure ET. A Mariotte bottle (on the left in the figure above) maintains a constant
water level in the CSW mesocosm and changes in water level in the mesocosm, as measured by
an ultrasonic level, can be directly correlated to the rate of ET.
Location: Located at the top berm of the constructed stormwater wetland.
Quick Facts:
-
The CSW lysimeter was created using a 0.46 m diameter and 0.61 m deep barrel with the
CSW soil and plants. Typically a 12 cm ponded water surface is maintained.
Total rainfall, percolation through the bucket (i.e. infiltration), relative humidity, solar radiation,
temperature, and wind speed were measured and recorded by a Campbell Scientific CR1000
datalogger located roughly 2 m from the weighing lysimeter.
15
All of this work wouldn’t have been possible without the support of our sponsors who have
joined us in our mission to advance the practice of comprehensive stormwater management.
Our special thanks to Pennsylvania Department of Environmental Protection (PADEP) 319 NonPoint Source Program, Pennsylvania Growing Greener Grants, the PA CZM program and the
William Penn Foundation. We also want to thank VUSP’s partners, members and friends and
VU Facilities Management Office.
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