Planning for a Rainy Day

Studying the path of stormwater

Traver Wadzuk Welker

Villanova’s campus – filled with graceful buildings of stone and brick, a wide lawn bordering Lancaster Avenue, towering trees and lush landscaping— is stunning in the sunlight. But for the students, faculty and civil engineers who form the Villanova Urban Stormwater Partnership (VUSP), it’s even more spectacular in the rain.

That’s because every time the clouds burst, the campus transforms into a living laboratory for their field of study: what to do with all that water—otherwise known as stormwater management.

As raindrops fall and gather in force and volume, certain features of the campus that may seem ornamental gradually start to demonstrate their function. Elements such as strategically positioned rain gardens, carefully tended green roofs and porous concrete walkways capture and absorb the water, allowing it to soak slowly into the ground.

These are just a few of the stormwater control measures designed by the VUSP, which was founded in 2002 by College of Engineering professor Robert Traver, PhD, PE, D.WRE, F.EWRI, F.ASCE, ’82 MS, a nationally leading expert in stormwater management. COE professors Andrea Welker, PhD; Bridget Wadzuk, PhD, ’00 COE; and John Komlos, PhD, also serve as VUSP faculty. As a partnership between Villanova’s Department of Civil and Environmental Engineering, the Pennsylvania Department of Environmental Protection, and private industry, the VUSP has been transforming the old thinking on stormwater management by using Villanova’s campus as a model of innovation.

“The Villanova Urban Stormwater Partnership has been a phenomenal resource for the stormwater management community throughout Pennsylvania,” says Janet Bowers, executive director of the Chester County Water Resources Authority. “My agency gets timely, relevant, scientifically sound information from them that is invaluable to us in providing practical technical guidance for the land developers in our municipalities.”

Bowers also praises the Pennsylvania Stormwater Management Symposium, a biennial conference hosted by the VUSP that brings together representatives from academia, municipal governments and the private sector. “This conference presents the most cutting-edge information about stormwater management in a way that’s relevant to researchers and practitioners all around the commonwealth,” she says.

A new approach

“In the past, stormwater management focused on dealing with the impact of extreme storms, such as Hurricane Katrina, but it’s even more important to manage water from more typical storms that produce an inch of rainfall or less,” Dr. Traver says.

Ideally, most of this water should evaporate or be absorbed by plants that return it to the atmosphere (a process known as evapotranspiration), or it should soak through the soil to replenish groundwater supplies. However, hard, impervious surfaces—from rooftops to parking lots to sidewalks—impede this process, creating surface runoff. Conventional stormwater management involves collecting this runoff in drainage pipes and discharging it into nearby bodies of water.

This “get rid of it quickly” approach can cause numerous problems, including erosion, downstream flooding and reduced groundwater. The water can also collect toxic chemicals as it travels over hard surfaces and ultimately pollute rivers and streams.

“A more sustainable approach is to mimic natural hydrology by allowing water to filter into the ground,” Dr. Traver says. “We do this in a way that supports and contributes to the campus infrastructure.”

For the past 12 years, the VUSP has been developing and testing a variety of sustainable approaches at numerous stormwater control sites throughout the campus. But many people probably never recognize these areas as research sites. They simply regard them as unique and lovely parts of the campus that they pass by, over and under every day.

Pointing out their true value is a skill honed by doctoral student Amanda Hess ’14 MS and master’s students Gerald Zaremba and Conor Lewellyn, who lead tours of the stormwater control sites for everyone from local high school students to civil engineering professionals visiting from other countries.

Fedigan rain gardens

As students walk through the front door of Fedigan Hall, they are able to admire the gardens on either side of the entrance, featuring hardy, water-loving woody plants, grasses and herbs. These are the Fedigan rain gardens, constructed in 2009 to capture and collect water from the building’s downspouts. The west garden incorporates a plastic liner and holds water longer, allowing the plants to soak it up and return it to the atmosphere. The east garden has no liner and lets water slowly infiltrate into the soil. These slightly different designs allow researchers to compare each garden’s performance over time.

The Fedigan rain gardens are just two of 16 rain gardens on campus. They contain mostly native plants, but rain gardens that collect parking lot runoff also may contain coastal varieties, such as those indigenous to New Jersey, which can withstand saline environments. This is particularly important in the winter, when the runoff frequently contains rock salt for melting snow and ice.

Hess, who studies evapotranspiration from rain gardens, notes that people often comment that they wouldn’t have noticed the gardens unless they were pointed out. “I like this comment, even though it seems to downplay the gardens’ importance,” she notes. “When people recognize that stormwater control measures can be unobtrusive and aesthetically pleasing, hopefully it will make measures like rain gardens more commonplace.”

CEER green roof

When Villanovans sip their lattes at the Holy Grounds coffee shop in the Center for Engineering Education and Research (CEER), they’re relaxing under a green roof, which was constructed in 2006 as a retrofit project on the existing roof. It’s planted with several varieties of sedum, a hardy species with a shallow root system and water-storing leaves that can withstand harsh environments.

The green roof absorbs and stores the first half-inch of water that falls on it during a storm, which fortifies the plants and allows evapotranspiration to occur. It also protects the conventional roof beneath it from the sun’s damaging ultraviolet rays.

“Green roofs offer an insulating effect in the winter and a cooling effect in the summer,” notes Zaremba, whose research focuses on quantifying and modeling evapotranspiration from green roofs. “And they can last up to 50 years and possibly longer with proper maintenance.”

Pervious walkway on “the Quad”

On rainy days, “the Quad” between Sullivan and Sheehan halls serves as a passage for both students and stormwater. Originally paved with asphalt, the Quad was reconstructed with pervious concrete, which lacks sand and other fine particles found in regular concrete, and allows water to flow through unobstructed.

Underneath the concrete lie three infiltration beds, which temporarily hold the rainwater that falls on the pathway, as well as the flow from the roof drains of the adjacent residence halls. The water then percolates slowly into the earth below.

The pervious walkway was the first of its kind in the region, and its construction had its fair share of bumps. The original surface, which was installed in 2002, quickly degraded. The pathway was reconstructed in 2003 with a combination of traditional and pervious concrete; it required additional repairs in 2004.

Throughout this process, the VUSP was open about the project’s successes and failures, which was as unusual as it was invaluable, according to Bowers. “Villanova was willing to admit that something was wrong, and they were open about how they planned to fix it,” she says. “And the rest of the stormwater management community got the benefit of learning from their experience.”

Other sites include a stormwater wetland in the northeast region of campus and a treatment train on the eastern side of the St. Augustine Center for the Liberal Arts parking garage, which routes water through a series of stormwater control measures, including two rain gardens.

Whether these sites are in high-traffic areas or tucked away in more remote corners of campus, they all share one common feature, notes Lewellyn, whose research focuses on examining the water quantity and quality in the treatment train. “Each site solves a problem unique to that particular location,” he says. “And each one is a fully functional system, in addition to being a research site.”

Future plans

Planning, designing and maintaining the stormwater control sites is a joint effort involving the VUSP and Villanova’s Facilities Management team, led by Associate Vice President of Facilities Management Robert Morro. “In most cases, the VUSP members will propose a project, and then we’ll walk around campus together and assess different areas,” he says. “We then share the responsibilities of building and maintaining each site. We embrace any opportunity to work together to help educate students and benefit the campus.”

Morro notes that the lessons learned from the current stormwater control measures will carry forward as Villanova undertakes major expansion projects, including replacing the parking lots along the south side of Lancaster Avenue with new residence halls, a performing arts center and a pedestrian-friendly townscape. “Our design concept already includes rain gardens, vegetated swales, pervious concrete for parking areas and sidewalks, and even a green roof on the performing arts building,” he says.

Morro adds that in October 2013, Radnor Township passed a stormwater fee ordinance, based on the amount of impervious surface, which costs the University nearly $86,000 per year. “Eventually, we hope to get monetary credit for current and future stormwater control measures to reduce this fee,” he says. “But we’d take these measures regardless of the financial benefits. Implementing responsible and innovative stormwater measures is a vital part of our students’ education—and it’s also just the right thing to do.”

Tapping the experts

Villanovans are nationally recognized for their research capabilities and expertise. Since January, for example, the total amount of funding awarded to Villanova faculty for stormwater-related research has exceeded $2.6 million. Among the grants is a $565,000 William Penn Foundation award presented to the Villanova Urban Stormwater Partnership for the development of a watershed protection strategy for Philadelphia. The National Science Foundation awarded $800,000 for the research and development of smart stormwater green infrastructure systems.

At a September press conference, Dr. Robert Traver led members of the American Society of Civil Engineers’ Task Committee on Flood Safety in presenting a report on lessons “observed but not learned” from Hurricane Katrina. Dr. Traver highlighted actions that can reduce the nation’s exposure and vulnerability to the consequences of flooding.