Combined Sewer Overflow: Why Our Waterways Stink

by GWAPP on

Last week’s thunderstorms didn’t just threaten the annual fireworks show, they threatened the surrounding areas’ waterways. How, you might ask. More than half of New York City’s sewers operate using a Combined Sewer (CS) system. A CS system means that sanitary and industrial wastewater, rainwater, snowmelt and street runoff all go into the same sewers as they head to the City’s treatment plants. And when there’s too much wastewater, rainwater and runoff and the CS system is over capacity–like during a thunderstorm–that liquidy mess runs directly into our area waterways, such as Newtown Creek or the East River. This is called a Combined Sewer Overflow (CSO) event.

What’s the harm of a CSO event?
Basically, a CS system can only handle a certain amount, and when the CS system is working correctly all those various waters and debris get properly treated at a city treatment facility, such as the Newtown Creek Wastewater Treatment Plant on Greenpoint Avenue. But when the system is overloaded much of the intake is NOT properly treated, most often bypassing the treatment facility completely, and going directly in the waterway. “Combined sewer overflows (CSOs) may discharge untreated sewage when it rains.” Untreated sewage being human waste, trash, litter and other gross things you don’t generally want going into your local waterway without first being treated.

If you prefer a visual explanation (with cute instrumental music), check out The Center for Urban Pedagogy’s great (and brief) video on CSOs. Watch it below.

Why should CSOs matter to you?
If you’re a North Brooklyn resident, or even a tourist visiting the waterfront to snap photos of the Manhattan skyline, wouldn’t prefer your waterway not be… well, gross? CSO is a cause of the many bad smells emanating from the water and the unsightly debris floating in the water; is why we can’t/shouldn’t swim or eat fish from the water; and is why our waterway poses such a health risk to us.

What can you do?
Being well-informed on this issue is a great place to start. See the end of this post for helpful resources. Be conscientious of your water usage, and use less water, particularly during storms and the immediate days afterwards. Visit the Newtown Creek Wastewater Treatment Plant, go on one of their tours and ask lots of questions.

Newtown Creek Alliance (NCA) even has a “flush meter” on their website to let you know if it’s safe to flush–when it’s in the red, assume that your toilet flush is going straight into Newtown Creek. (Yeah, just take a minute and actually think about that.)

If you’re on Twitter, follow Newtown Creek Alliance (@NewtownCreek)–they regularly and seemingly automatically post CSO alerts for Newtown Creek. Side note: As of writing this blog post on Sunday evening, there is still a CSO alert in effect from Thursday’s thunderstorms according to @NewtownCreek.

And lastly, support Green Infrastructure endeavors such as “green roofs, rain gardens, and Right-of-way Bioswales on City owned property… Green infrastructure promotes the natural movement of water by collecting and managing stormwater runoff from streets, sidewalks, parking lots and rooftops and directing it to engineered systems that typically feature soils, stones, and vegetation. This process prevents stormwater runoff from entering the combined sewer system.”

For more on CSOs and NYC sewers, check out:
Types of Sewer Drainage Areas in New York City
Newtown Creek Alliance’s Weather in the Watershed
NYS DEC CSO Wet Weather Advisory
NY Times Sewage Flows After Storm Expose Flaws in System
NYC Green Infrastructure Program



The Greenpoint Waterfront Association for Parks & Planning, Inc. ("GWAPP") is a not-for-profit group, 501(c)(3), comprised of individuals, community organizations, religious institutions, and concerned citizens from the Greenpoint-Williamsburg communities dedicated to the development of parks and public access on the Greenpoint waterfront.