For all of its arguably practical planning, New York City has a major flaw: its combined sewer system. The pipes that whisk all of our raw sewage to one of the fourteen wastewater treatment plants around the city were also designed to carry rainwater as it ran off the city’s streets. The only problem is that the pipe system and the treatment plants are not equipped to handle the volume of raw sewage and rainwater that we feed them. So where does it all go, if it doesn’t get treated?
As little as about one tenth of an inch of rainwater in an hour can overload the system and cause a combination of rainwater and raw sewage to pour from any of the 460 outflow sites around the city. These sites are scattered up and down the Hudson and East Rivers, Jamaica Bay, Coney Island, and Flushing Bay. It is estimated that about 27 billion gallons of combined sewage overflow (CSO) enter New York City’s waterways every year.
If you aren’t grossed out yet, you should be. Combined sewage overflows often result in the closure of beaches and waterfront areas. And for good reason: the sewage that pours out contains over 40 different types of disease-causing bacteria, toxic heavy metals, and pesticides, among other unpleasant things. That sewage-chemical mix, mixed with all of the garbage that gets washed off city streets, has slowly been turning the water around New York City into a literal cesspool.
People started connecting CSOs to compromised water quality in New York in the 1950s; why is this still a problem? To put it simply, putting in a whole new sewer system just isn’t in the budget. Some attempts have been made over the years, but a comprehensive end-of-pipe filtration system would still cost over $2 billion.
Luckily, some alternative solutions to the CSO problem have been kicked around over the last few years, focusing instead on the excess water before it hits the pipes, instead of after. Installing green roofs, street trees, or permeable pavement would divert water from the sewer system altogether. These solutions have multiple benefits, besides beautifying the city. Water absorbed by plants would get naturally filtered; the better plants are watered, the more able they are to cleanse the air of nasty pollutants. Similarly, water absorbed through permeable pavement would help replenish New York’s water table.
The war against CSOs can be waged at a small scale, too. A planter box in your window could even make a small dent in the larger problem. You can also help by improving your local community garden or park.