In addition to greening the grounds, the University's plan to implement generative systems within the local watershed involves managing stormwater through an integrated, campus-wide ecosystem approach. The University has created an innovative stormwater management plan that incorporates a number of stormwater practices identified below.
Today, Princeton incorporates rainwater and condensate collection systems in many new building projects for reuse in toilets, landscape irrigation and/or groundwater recharge.
A green or "living" roof, such as the one on Butler College, is a rooftop garden that filters, delays and reduces the volume of stormwater runoff; minimizing physical scouring and stresses associated with toxins, sediment, and excess nutrient loads. Butler College's green roof comprises 58 percent, or 65,540 square feet of a 113,000 square foot roof and has 14 varieties of hardy sedum planted. Learn more about the Butler College green roof installation.
Butler’s green roof is also an active demonstration of the University's approach to integrating academic and operational pursuits, with live performance data continually monitored by faculty and students, and outcomes informing future green roof projects.
Green roofs currently grow on Butler College and Sherrerd Hall, and are planned for future buildings. There are also a number of underground buildings that have greenspace lawns over their structures: among these are Whitman College, Firestone Library, McCormick Hall, Fine Hall, and Lewis Thomas Laboratory.
Rain gardens retain and filter stormwater, providing benefits to the local watershed and stream systems by encouraging stormwater infiltration and reducing erosion. The rain garden at the Frick Chemistry Laboratory was the first installation on campus, with others following at the new Neuroscience Institute and Peretsman-Scully Hall, and other sites.
Detention basins retain water to slow down stormwater runoff while simultaneously limiting flooding during heavy rain. Basins are pond-shaped depressions that perform some of the same functions as rain gardens, but do not have the extensive vegetation plantings for enhanced filtration. The campus currently has six detention basins, with locations that range from outside of the Frick Chemistry Laboratory to near the Lot 7 Garage.
Water Recharge Systems
A groundwater recharge system directs rain into subsurface gravel and sand beds. Similar to green roofs and rain gardens, the primary goal of recharge systems is to reduce surface runoff and erosion, and maximize replenishment of groundwater reserves.
The University has installed groundwater recharge systems beneath Princeton Stadium, Roberts Stadium, 1952 Stadium, Finney Field, Campbell Field, and other athletic fields.
The University is reducing the amount of paved surfaces around campus with surfaces that are permeable - or, surfaces that allow liquid to pass through. These features enhance biofiltration of surface runoff, improving local water quality.
The new Neuroscience Institute and Peretsman-Scully Hall building site reduced impervious surfaces by more than ten percent. Even with growth in building square footage, the current Campus plan (complete in 2017) will result in a net increase in pervious surface area on campus.