After major storms flooded low-lying areas of Pittsburgh repeatedly in 2004, 2009, and 2011, Carnegie Mellon University is now in the final stages of a major stormwater management project that will redirect floodwaters from major storms toward constructive uses for both the city and campus.
Since early May, construction crews have been excavating the area known as the Mall between the College of Fine Arts and Hamerschlag Hall. With the help of a 500-Mg (550-ton) crane, the crews will install four large concrete tanks measuring 416 m2 (4480 ft2) in surface area underground in the coming weeks. Once set in place, the dig site will be refilled. University administrators expect full restoration of the Mall by early August.
The underground tanks will be able to collect up to 1.04 million L (275,000 gal) of water to be reused for chilled water cooling systems on campus. Additionally, a system of downspouts and catch basins from nearby campus buildings through the Mall will help to minimize the risk of severe flooding during heavy storms by collecting a large amount of stormwater runoff.
Excess water will be diverted into Pittsburgh’s stormwater system, which eventually flows into the Allegheny River.
Stormwater management is a major concern in southwestern Pennsylvania because of its hilly terrain, generally poor soil quality, and growing land development. Water from storms rolls down hills into low-lying valleys quickly, and because an abundance of clay in the soil weakens absorption and the landscape is packed with such impenetrable surfaces as parking lots, sidewalks, and roofs, the area faces a high flood risk year-round.
For more information about Pittsburgh’s unique stormwater challenges, click here.