Nine Mile Rerun
In Pittsburgh, activists bring a biologically dead stream
back to life.
By Peter Harnik
If Pittsburgh was “Hell with the lid off,” as it was
famously called during the worst of its industrial heyday, then its River Styx
was surely Nine Mile Run. Polluted into lifelessness, buried in culverts,
insulted with trash, gouged by flash floods, and stripped of its floodplain by
vast piles of slag, Nine Mile Run was as close to biological death as a stream
could get. Today it is the site of the largest urban stream revitalization
project ever undertaken by the U.S. Army Corps of Engineers.
It is fitting that Nine Mile Run would be the site of such a
grand experiment. For, as Jane Jacobs pointed out in her book The Economy of Cities, it is large urban
areas that are always the first to confront mankind’s newest problems, and they
are also always the first to be forced to solve them. The very industrial
processes that led to Pittsburgh’s once-immense wealth also caused
unprecedented problems for Nine Mile Run. Today the city is using some of that
old wealth along with the creative energy of its politicians and some of its
newest residents to devise solutions. But fixing the environment is harder than
damaging it in the first place.
Nine Mile Run was named for the distance from its mouth on
the Monongahela River to Pittsburgh’s Point, where the “Mon” meets the
Allegheny to form the Ohio River. (Actually, they counted wrong; it should be
Seven and a Half Mile Run.) Over the decades Nine Mile Run has been severely
modified. The entire lattice of its five-mile-long upper watershed is buried
under the streets, yards, and buildings of the eastern edge and suburbs of
Pittsburgh. Eventually the westward-flowing waters reach the lush forest of
Frick Park and emerge for the first time into the open, 2.2 miles upstream from
the Monongahela. Soon after, the run merges with its main tributary, Fern
Hollow, coming in from the north through the center of Frick Park. Joined
together, the larger stream flows southwest under the massive superstructure of
I-376, the Penn Lincoln Highway. The final race to the Monongahela takes it
through a narrow channel between two astoundingly steep and high banks of slag
that had been dumped for half a century on the former wetlands and wide
floodplain of the stream.
In 1998, the last year of its almost two centuries of
deterioration, Nine Mile Run was what is called a “flashy”—as in “flash
flooding.” It’s a characteristic of most urban streams. Five million dollars of
reconstruction later, it is still flashy, but a bit less so. And every
succeeding year its ecology functions a bit better. To understand the
problem—and the solution—requires getting down into the streambed.
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