How nyc is working to fix pollution caused by combined sewer overflow – curbed ny

New York City is full of peculiar phenomena—rickety fire escapes ; 100-year-old subway tunnels ; air conditioners propped perilously into window frames—that can strike fear into the heart of even the toughest city denizen. But should they? Every month, writer Ashley Fetters will be exploring—and debunking—these New York-specific fears, letting you know what you should actually worry about, and what anxieties you can simply let slip away.

Every now and again, during a wet and rainy season, the horror stories bubble up and burst forth: Heavy rain in New York City, which in many places drains into the same pipes that direct raw sewage to wastewater treatment plants, causes the whole rainwater-wastewater mixture to flow into the rivers and waterways around the city.


This results in some New Yorkers kayaking in other New Yorkers’ toilet water (and some of their trash, which rainwater can also pick up on the streets).

It’s normal—perfectly warranted, even—to worry about city dwellers’ poop contaminating the creeks, rivers, and bays around the city, especially when fecal contamination, according to the environmental nonprofit Riverkeeper, puts any human in contact with the water at risk for several kinds of bacterial and viral illnesses, as well as parasites like giardia.

Combined sewers as an infrastructural feature are largely a thing of the past in New York as well as in other cities; as a New York Times story on the subject points out, most water systems built after the 1950s drain wastewater and rainwater separately, with rainwater flowing into waterways and wastewater flowing exclusively to treatment facilities.

The bad news for New Yorkers is that most of New York was built before the 1950s—so “combined sewer overflow” can happen just about anyplace that’s next to a waterway if the weather gets wet enough. The website for the State of New York has a map of every “CSO community,” where residents are advised to “Avoid contact or recreation (swimming, boating, and fishing) within the waterbody during or following rainfall or snowmelt,” and, well, here’s a screenshot of that map:

The worst years of the potentially disastrous combined-sewer system seem to be, thankfully, behind us. In December 2017, the De Blasio administration released a report that New York Harbor had recently tested “cleaner and healthier than it had been in more than a century,” with bacteria levels dropping and dissolved oxygen levels on the rise.

The mayor’s office credited the city’s massive spending to overhaul the combined-sewer systems: Over the next few years, the city will spend more than $6 billion separating the rainwater and wastewater pipes, adding new overflow-retention tanks and interceptor sewers (and upgrading existing ones), and installing “curbside rain gardens” to create more absorbent space in a city where more than 70 percent of the ground is covered with impermeable surfaces.

Grassroots efforts like the Newtown Creek Alliance, which encourages residents to cut down on sink, shower, toilet, and washing machine use during wet weather, have also inspired the city to work directly with residents to remind them to hold off on using their in-home water systems. Starting in April, residents of neighborhoods in northwest Brooklyn to eastern Queens—where water use during storms can trigger overflows into Newtown Creek, Bowery Bay, Flushing Creek, and Flushing Bay—can sign up (for free) to get these reminders via text message whenever the weather gets stormy enough to potentially trigger a CSO.

Elsewhere in the world, there’s great concern over combined-sewer overflow’s potential contamination of drinking water; in Montreal, for example, researchers investigated this very possibility in 2015. In New York, however, there’s virtually no way combined-sewer overflow could affect the city’s drinking water supply, which flows downstate from three major watersheds north and west of the city, far upstream from the Hudson. It travels through an elaborate system of reservoirs and filtering and treatment facilities, then finally from a reservoir in Yonkers through just three major tunnels and up into our homes, bypassing the city’s waterways entirely.

So that’s one fear assuaged. But as the weather gets warmer (one day, soon, hopefully; please God) and city dwellers start thinking about where to next hop in the water to cool off, it’s of course wise to avoid the areas affected by CSOs. You’re better off swimming only where there’s plenty of tidal flushing—that is, where the water flows out pretty quickly and dramatically—and only when the weather has been dry for a few days.