Monday, June 28, 2010

Four Mile Run

The historic creeks of Squirrel Hill are buried under the city, and there isn't really any room to 'daylight' them. There are,. however, historic streams right in Pittsburgh that could see the light of day again, in our lifetimes or even in the next few years, if funding and public support could be found for daylighting work...

Four Mile Run has two main forks, one that runs from east to west and the other from north to south. The latter, which is on this map stretching north from the 'Highway 40' sign, once ran through what is now Schenley Park, but is now routed into the connected sewer-stormwater runoff system. Why would people bother to put a stream in a park underground? Well, in the late 1800s and early 1900s, the stream was a repository for raw sewage so it didn't have much recreational value. Putting the stream underground was a public health issue.

I visited this historic channel recently. It now contains a bike trail and a railroad line.


The channel is used by bikers and joggers, but is generally underutilized. The sides of the narrow gulch are covered in dense invasive plants and not accessible. However, the area is still interesting, and there is a nice view of the Boulevard of the Allies bridge.


The channel contains some sports fields.


The run then passes under this small railroad bridge and a larger highway bridge.


The highway bridge has some huge downspouts on it that have oveflow issues at times (see below) and also has a playground under it as well as some space where construction appears to be occurring. This area is a possible candidate for some water art or runoff mitigation that people could see in action while sheltering from rain or spending time at the playground.


The Pittsburgh Parks Conservancy is looking into the possibility of initiating a daylighting project on this stream. This would add greatly to the recreational values of the underutilized western end of Schenley Park while also providing habitat for wildlife. It would also channel runoff from Panther Hollow Lake and other areas (but not the entire historic Four Mile Run watershed) through the restored stream directly into the Monongahela River - without any added sewage. This would decrease the load on the combined sewage-stormwater runoff system that causes sewage to wash into the lake.

The project would also greatly benefit people living in the neighborhood under the parkway bridge (near Big Jim's). These following photos, sent to me by resident Michael Vincent, are a dramatic illustration of the problems with the sewage-stormwater system. On multiple occasions this area has experienced sewage overflows during storms. Yep - that isn't just highway runoff - there is raw sewage in that water too. Daylighting the stream, along with building rain gardens and installing rain barrels, will decrease the occurrence of this sort of overflow in this neighborhood.

Four Mile Run Flooding - Michael Vincent

Four Mile Run Flooding - Michael Vincent

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