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Can a Parking Lot Be Good for the Bay?

August 20, 2008 12:00 PM

UMBC Workshop to Teach Builders, Planners
About ‘Green Concrete’ in Classroom, With Cement Truck

Can a Wal-Mart parking lot be good for the Bay?

The answer could be yes, if it’s made of pervious concrete, a ‘green’ building material that is the subject of a how-to workshop hosted by UMBC's Center for Urban Environmental Research and Education (CUERE) on Wednesday, Aug. 27 from 8 to 11 a.m.

Pervious concrete allows stormwater to slowly drain through it like a sponge. This prevents the rapid runoff of rainwater from traditional concrete that erodes waterways and carries pollution into the Chesapeake Bay. Voids left in the mix give pervious concrete a bumpy texture and allow water to soak through.

Experts from UMBC and Cleveland State University will give contractors, tradesmen, architects and municipal planners a classroom session on best practices for working with the material and for navigating Maryland's recent changes in development laws, such as the Maryland Stormwater Management Act of 2007, which calls for “environmental site design” for new construction and development.

At 10 a.m. a concrete mixer truck will arrive for a hands-on lesson in the proper pouring and installation of the material. Several test beds of pervious concrete will be installed outside of the CUERE facilities.

The test beds will be equipped with scientific instruments to give UMBC researchers long-term data on pervious concrete's effectiveness both as a building material and as a tool for environmental stewardship. Gwen Stanko, a doctoral student in CUERE's prestigious IGERT program, and other UMBC students will help monitor the test beds.

Photo Caption: Stu Schwartz (right) and UMBC Ph.D. student Gwen Stanko with pervious concrete samples near a future test site.

The event was organized by Stu Schwartz, a senior research scientist at UMBC CUERE with over 15 years of experience in land use and water quality issues.

Schwartz says the workshop’s goal is to improve understanding of pervious concrete. While there are differences in how to mix, pour and maintain pervious versus traditional, when properly installed and maintained, it is effective for light-traffic parking lots, roads and sidewalks.

“In the past, people have promoted pervious concrete as a magic pavement that makes all your water problems go away," said Schwartz. "There's no such thing as a magic bullet like that. Many of the negative stereotypes associated with the material have been caused by improper design and installation. So we want to provide information for contractors, engineers and planners to know when and how to use it effectively.”

According to Schwartz, industry is starting to invest more in pervious concrete as both a way to comply with environmental rules and as a boost to the bottom line. He noted a Wal-Mart parking lot in Denver, Co., made of pervious concrete and a seven-acre paved storage yard and parking lot by Shelter Systems, a Westminster, Md., roofing truss company.

“Pervious concrete allowed Shelter Systems to use their entire seven-acre site instead of losing an acre or acre and a half to stormwater ponds, saving the cost of a $400,000 stormwater management system,” said Schwartz.

The workshop and research effort is funded by the Chesapeake Bay Trust, part of the organization's new Pioneer Grant Program, which focuses on larger, higher-impact grants to improve the health of the Bay.

Photo Caption: Stanko demonstrates how a pervious concrete sample lets water flow through.