By Bridget Wadzuk, PhD, Contributor and Professor in the Department of Civil and Environmental Engineering at Villanova University
THE U.S. CONTINUES TO set new marks for the rainiest months on record. From July 2018 to June 2019, the country had on average 7.9 inches more rain per month than the long-term average, making stormwater a crucial environmental issue.
Green stormwater infrastructure—such as rain gardens and bioswales that allow rain to sink into the ground—is a strategy to help decrease the frequent flooding urban areas face after heavy rain. As municipalities across the country continue to grow there is a need for more resilient design and green infrastructure mitigates problems associated with our changing climate and increased flooding.
I am part of a research team at Villanova University‘s College of Engineering that has been studying green stormwater infrastructure on our campus for more than 20 years. As the synthesis of this research and a commitment by the University to build sustainably, Villanova opened a new complex of residential halls, The Commons, on a site previously occupied by a nearly 10-acre parking lot of impermeable asphalt. This new construction included a highly innovative stormwater design to manage more than 2 inches of rainfall per storm. Using green infrastructure, the rain remains where it falls instead of moving to a storm sewer that can overflow and cause flooding along roadways. This will positively impact not only Villanova but the surrounding community.
Our research team of faculty and students will benefit from this new complex by using the site as a living laboratory for our stormwater management research and education. There is truly no better lab than the environment around us.
This partnership with the University and its Facilities Management Department is not a new one. It began in 1999 when the University supported researchers from the Villanova Urban Stormwater Partnership to convert a detention basin into a constructed stormwater wetland. Since then, research initiatives and University-led efforts developed more than 20 rain gardens, three green roofs, and multiple green infrastructures that manage stormwater around campus.
The project team at Villanova used knowledge gained from our research in the planning of its new $225 million campus development, creating a plan that met regulatory requirements with leading-edge solutions. While the University was working with partner firms to design and build The Commons, the Facilities Management Department collaborated with the College of Engineering. Project managers and researchers worked together to test the rain gardens during construction to ensure they met design specifications. Facilities also added in additional elements—such as access to power and wifi to support monitoring equipment—that will go a long way in making this complex a long-term research facility.
The new site has four rain gardens, three bioswales, three infiltration trenches and two large underground cisterns that will take rain that falls on nearby roads and rooftops. The rain gardens, bioswales and trenches are located at the ground surface, allowing runoff to slowly seep into the ground, which filters out pollutants and recharges the groundwater; the plants within the systems provide ecosystem services and are aesthetically appealing. The underground cisterns are part of a stormwater harvesting system. While stormwater harvesting can often capture a lot of water, it can be hard to use all the water by the next time it rains. The system Villanova installed will reuse this stormwater through the new buildings’ HVAC system, which is used all year round and not strictly tied to user demand. It also means the University will save money by not using potable water for the HVAC.
In fall 2019, two undergraduate Engineering students will begin post-construction monitoring for water quality and water quantity. The collected rainfall and flow data will be compared against pre-construction monitoring data and the whole complex will be assessed to determine how well the design is working. The total rainfall captured on site will be quantified and the usage of the harvested stormwater from the cisterns will be measured.
The findings of this work will be used to demonstrate to the University how green infrastructure can effectively meet municipal requirements. Beyond that, these findings will help promote green infrastructure as a stormwater solution in cities across the country. Our research team shares best practices with organizations, municipalities and township officials, and other community groups through the Villanova Urban Stormwater Partnership.
Researchers across all disciplines seek solutions to problems that will impact the world around them. As someone who studies green stormwater infrastructure, I can attest to the fact that researchers must continue to play a critical a role in helping cities address growing issues of flooding and resiliency. Our work leads to the creation of new knowledge and through collaborative work and partnership, we can share best practices so that they can become part of land development policies to benefit the environment and society.
Nave Newell is proud to have worked on this highly innovative stormwater design. Read more about the project here.