Monday, February 16, 2015

A Ray of Hope

On Friday morning, February 13, I joined my landscape restoration students for tours of an urban oasis featuring the latest stormwater management and native gardening concepts.  My graduate students gathered for their tour at 8:30 a.m., and then my undergraduates met at 11:00 a.m. for a second tour.  When we got to the site, the temperature was 8 degrees F, and the wind was blowing strongly.  To say it was cold was an understatement, and the temperature had only risen to about 18 when the undergraduates convened for the second tour.

The site was the Salvation Army's Ray and Joan Kroc Community Center in Philadelphia.  Ray Kroc, founder of McDonald's restaurants, and his wife, Joan, gave the Salvation Army over $1 billion to build community centers in severely disadvantaged urban neighborhoods across the country.  I'm not much of a fan of the Salvation Army (because of their discriminatory practices) and everyone has an opinion about McDonald's.  Our tour leader, Chris, shared my opinions about both organizations, but he conceded that the community center was a godsend for the impoverished neighborhood in which it was located and he commended the Salvation Army for its good deeds here.

The site had been a lightly-contaminated brownfield associated with the Budd Manufacturing Company, one of Philadelphia's largest employers when manufacturing was king.  Budd's thousands of workers built zeppelin gondolas, railroad cars, and airplane parts.  Today, the factory buildings are vacant, derelict and marred by graffiti.  The 13-acre Kroc site had been a parking lot for Budd's workers.

When the Salvation Army decided to locate the community center on the site, they hired the local but widely-renowned landscape architecture firm Andropogon (named for a genus of native grasses) to design the landscape.  With Philadelphia's extremely strict  stormwater management regulations, the Salvation Army insisted that the designed landscape capture, retain, and infiltrate as much water as possible.  Andropogon's designers also decided to make the project "zero waste" - no material would be removed from the site.

All of the existing parking lot pavement was either recycled to be reused for porous pavement on the new parking lot or was spread to level the site.  Slightly contaminated soil was buried deep under the site and encased in compacted soil.
Bioswale
The new porous pavement parking lot was divided into sections separated by bioswales.  Any stormwater which does not drain through the porous pavement runs into the bioswales planted exclusively with native species.  Stormwater which fails to infiltrate in the bioswales is gathered into one location and diverted to an extended detention and infiltration basin called Rain Garden B.
Roof stormwater management system
The community center building covers two acres.  The architects determined that installing a green roof would have been prohibitively expensive.  So, instead, they worked with Andropogon on an alternative.  Rain falling on the roof collects in three locations and spills into downspouts integrated into the building's design.  The spouts discharge into decorative runnels, which direct the water into one of two cisterns buried in the center of the site.  The cisterns were designed to supply water to the property's landscape irrigation system but, unfortunately, the irrigation system failed soon after it was completed and now the cisterns simply discharge into Rain Garden A when they are full.
Cleverly disguised downspouts and decorative runnels
Tour leader Chris demonstrating the capacity of the runnels
Small rain events fill just the central sculpted channel in the runnels, while larger events fill the broader channel.
Sculpted runnel designed to look like flowing water

Students standing at he edge of Rain Garden A that receives the discharge from the roof cisterns
All three of the rain gardens on the site were dry when we visited..  If Rain Garden A fails to infiltrate all of the stormwater it receives from the roofs, the excess water can flow into Rain Garden B, which collects water from the parking lots.  And, if Rain Garden B cannot infiltrate all of the water, the excess flows to Rain Garden C, which also includes a structural outlet to the city's stormwater sewers - a "fail safe" in the event of a major flood.  Chris emphasized that Rain Garden C had never spilled any water into the city's sewers since it had been built (though he admitted that we hadn't had a hurricane yet, either).
Rain Garden B on right of path
Last stop.  Rain Garden C, which can handle the overflow from A and B, if necessary.
The plantings in Rain Garden C included some bald cypress trees in the bottom of the basin.  Bald cypresses will survive this far north, but they are not part of the native flora.  I didn't challenge Chris on the issue, so I can't explain the reasoning behind planting cypress (versus a more northern species that could also tolerate wet feet like swamp white oak, pin oak, or sycamore).  With global warming, the cypresses may be very happy in the near future, but there was no evidence of global warming on the morning we visited!

6 comments:

Mark P said...

We haven't had temperatures that low this winter, I'm happy to say. We may reach near that this week, though.

I like the concept of the zero waste site. it's a neat idea, and it sounds like it was pretty well executed. I was surprised to read that they used cyprus.

packrat said...

Fascinating blog post, Scott! I love learning about these kinds of projects. I'd never heard that the Krocs had donated so much money for these developments. No matter what anyone may think of them (and I really know nothing about their lives) $1 billion + is nothing to sneeze at. Despite the cold your students must have appreciated the field trip.

robin andrea said...

Such an interesting, well-planned endeavor. I'm also impressed that the students showed up in such crazy cold temps. Pretty impressive.

Scott said...

Mark: It was really cold. At one point, we decided to visit a portion of the site shaded by an adjacent building; let me assure you we didn't stay there long.

I'll ask about the cypress the next time I see Chris.

Scott said...

Packrat: Most of the students seemed to have appreciated the field trip (though one undergraduate woman, after we had been outside for over an hour, asked if we could retreat inside because she said that her brain was numb).

If you listen to NPR, you may occasionally hear that Joan Kroc left a significant bequest to NPR.

Scott said...

Robin Andrea: The students had a choice: freeze for 1-1/2 hours or listen to me drone on for 2-1/2 hours. :) Actually, I think most of the students appreciated the site despite the cold.