New York City Water Trail Association

Water Trail Map

Water Quality

Go to a public hearing about harbor water quality and all the work that various governments agencies are doing to improve it, and you are likely to hear the following proclamation at least once, and probably several times: “The water is cleaner than it’s been in 100 years.”

There’s no doubt that the harbor is cleaner now than it was then. One hundred years ago the sewers of cities and towns on both sides of the harbor emptied directly into it. It wasn’t really until the 1970s and the passage of the Clean Water Act that we began to build an effective network of modern wastewater treatment plants. There have been consistent improvements to the system since then, and bacteria test results taken at mid-channel locations show that sewage pollution numbers today are generally quite low—low enough on most days to meet the swimming standards at the city’s bathing beaches.

Combined sewer pipe: dry weather vs wet weather

It’s a different story when it rains, however. In most parts of the city, stormwater running off of streets, sidewalks and roofs is dumped into the same pipe that carries sanitary waste from residences, offices and factories. The resultant flow of “combined sewage” is far too much for the city’s wastewater treatment plants to handle, so much of it—more than 20 billion gallons a year in all—is bypassed into the harbor via a network of combined sewer outfalls, or CSOs. Sewage plumes are typically quite diluted by the time they reach the middle of the harbor, and but nearer the shore there can be higher concentrations, and thus more risk for swimmers, boaters and fishermen.

 

Federal and state environmental regulators require the city’s Department of Environmental Protection (DEP) to come up with “Long Term Control Plans” to reduce and, ideally, eliminate CSOs. The DEP counters that to make more than incremental improvements in the system would be very expensive, and that the zero-CSO goal needs to be weighed against other city priorities. We understand the need for balance, but believe there are many things the DEP could be doing now, without embarking on major capital spending projects, to improve public awareness and enjoyment of the harbor.

Here’s a short list:

  • increase monitoring at near-shore locations where boaters, swimmers and fishermen are more likely to come into contact with the water and/or incorporate community science data into agency modeling and planning
  • establish flow monitoring at CSOs and create a real-time notification system so that the public has a clear understanding of when, where and how much individual CSOs are discharging
  • share rainfall data (the DEP has weather stations at each of its 14 wastewater treatment plants) and redesign the city’s water-testing database so that test results are up-to-date and accessible to the layman (as of April, 2023, the Harbor Survey database had not been updated for more than a year)
  • investigate illicit or accidental pollution sources at localized ‘hotspots’ where bacteria numbers are consistently high whether or not it has rained
  • work with sister city agencies and state and federal regulators to support increased recreational use of the harbor, especially swimming, within the Upper Harbor