Combined Sewer Overflow

Katie Blackley / 90.5 WESA

The Allegheny County Sanitary Authority, or ALCOSAN, revealed its plans to reduce sewage overflows by 7 billion gallons by 2036. The announcement Thursday began with something unusual: a round of applause for the sewage treatment plant.

Margaret J. Krauss / 90.5 WESA

Hundreds of millions of gallons of stormwater flow into Pittsburgh’s sewer system during hard rains, which results in chronic flooding and sewage backups. A massive green infrastructure project slated for Four Mile Run could significantly reduce those problems, Pittsburgh Water and Sewer Authority officials said.

midquel / Flickr

New data suggests that Pittsburgh sewer overflows may be 15 percent greater than prior estimates, which were based on data from 2003. A new report from the RAND Corporation analyzes data collected by ALCOSAN between 2004 and 2013.

 

Furthermore, the volume of water overflowing from local sewers could rise in coming decades, according to Jordan Fischbach, co-director of RAND’s Water & Climate Resilience Center.

Matt Nemeth / 90.5 WESA

At the south end of the Pittsburgh Zoo and PPG Aquarium parking lot is a small access road with a sign reading “Do Not Enter.” Beyond that is a big gravel parking lot, mostly used for overflow parking during large zoo events and as a staging area and storage space for the Department of Public Works.

One-tenth of an inch of rain over an hour is all it takes for the region’s sewers to overflow.

That’s according to the Allegheny County Sanitary Authority (ALCOSAN), which has already issued two Combined Sewer Overflow (CSO) alerts this season.  The Authority is hoping that as the river recreation season takes hold more recreational users will take note.