“What does not bend must break”

Last night’s storm was one of the strongest Pittsburgh has seen in years.  As the streets flooded and the wind blew, I couldn’t help but cringe thinking about what I’d see when I walked through the parks this morning.  What I did ultimately see was certainly disheartening, but a chat with Phil Gruszka and Erin Copeland, our Director of Parks Management and Maintenance and Restoration Ecologist, revealed that the parks had held up remarkably well.  I thought I’d share some of what I learned with you.

Frick Park
My first stop on the Tour o’ Destruction was Nine Mile Run, where a couple of DPW crew members were sweeping mud off the bridge near the Commercial Street parking lot.  They reported that the water had been higher than the top of the bridge at one point, but by morning the bridge was walkable (if slippery).  The most obvious things about the Nine Mile Run scene were the bent plants and the unusually high amount of trash.  The area around the bridge looked like the snack aisle of a convenience store, with just about every candy and chip wrapper imaginable stuck in the leafy debris.  Litter that’s tossed onto the ground in the neighborhoods surrounding the Nine Mile Run Watershed (Edgewood, Swissvale, Wilkinsburg, and Regent Square, to name a few) washes into the stream during a storm event, and this storm brought more than its fair share.  It’s absolutely true that what we do at home impacts our natural areas, even if we can’t always anticipate how.

Walking further along the stream, it seemed like almost all the tall plants had bowed in submission during the storm.  It looks grim now, but given a few days they’ll pop back up.  As Phil says, “What does not bend must break,” and floodplain plants are naturally able to go with the flow.  They take some of the hit from the stormwater, slowing it down and lessening its impact elsewhere in the wetland and on the trails.

Schenley Park

The Phipps Run Trail, with one of the basins to the middle right.

After checking out Nine Mile Run, I headed to Schenley Park to see how the Phipps Run stream engineering project the City and the Conservancy conducted about five years ago had held up.  The results did not look encouraging.  Water was still streaming down the steps, and all along the Phipps Run trail, there was a huge rut in the gravel.  As a regular park user, my perception was, “This trail is destroyed.”  But Phil explained to me that, far from being cause for despair, the appearance of the trail was actually a “Hooray!”

When the stream was re-engineered a few years ago, the purpose was to allow the trail to withstand unusually powerful storm events like this one.  Before the project, the trail was constantly washing out, making it impassable for hikers and bikers.  The City and the Conservancy mapped out an alternate course for the stream, allowing it to meander and slow down heavy flows of water.  Two basins were installed to catch sediment, so that in a storm like last night’s, heavy sediment is caught by the basins instead of rushing over the footbridges and into Panther Hollow Lake.  The heavy materials can slam into the bridges, causing them to crack or collapse, and collecting this sediment from the lake is much harder than collecting it from small basins. 

Panther Hollow Lake looks rough today, but the footbridge is still intact thanks to help from the re-engineered stream and the wetland plants.

The rut in the trail came from the water crossing over an edge that was placed to the left side of the trail.  This edge is meant to erode in storm events, directing water toward the Panther Hollow wetland, where it meets more of those great floodplain plants and slows down.  In a lesser storm, you wouldn’t see the rut, but it isn’t cause for alarm because the base material of the trail is still in place.  What happens next is that the City will remove the sediment that collected in the basins and use it in other areas of the park (for creating meadows and such), and bring in some gravel to fill the trail back in. 

In short, the stream behaved exactly as the project partners intended: none of the bridges were damaged, the basins did their job, and a few minor repairs will bring the trail back to its full use.  These repairs have to happen every now and then if we want to have streams as part of our parks–they’re beautiful to look at, but they are subject to the whims of nature just like everything else.

What Can You Do to Help?
I asked Phil how people could help out in the next few days, and his first piece of advice was to allow the City crews a few days to clear out the hazardous materials, like downed or damaged trees.  The north end of Frick Park was hit pretty hard, so mountain bikers would be wise to stay off the trails until they can be cleaned up.

If you want to get out in the parks and help clean up, the Nine Mile Run Watershed Association is having a stream sweep this Sunday, June 21 from 9:30am to noon.  You can help remove the trash that has collected in the wetland, which would make a huge difference in helping the area to recover.  Click here to learn more and sign up.

Want to see a little more of the storm aftermath?  Click here for more photos.

The Nine Mile Run stream, looking more robust than usual!