Cleaning the Toxic Water of New York City is Not Without its Challenges

By Jan Kobal

Clean Water Advocate Christopher Swain swam the entirety of the Gowanus Canal, one of the most polluted bodies of water in New York, on the 17th of October in order to help put “threatened waterways squarely in the public eye, and to support protection, restoration, and education efforts.”

This event brought renewed light to an ongoing issue in New York City – the occurrence of Combined Sewer Overflows (CSOs) and how they affect the City’s various waterbodies. These happen because the City’s outdated sewage infrastructure carries a combination of both storm water run-off and sanitary flow in the same pipe.

“Every time it rains, even just an eighth of an inch in certain parts of the City, the system will be overwhelmed and will have raw sewage flowing into our many waterways,” said Inger Yancey, President of Brooklyn Greenroof. “New York doesn’t like that, we want to be a clean city.”

The DEP states that these overflows are of great concern since they can “increase the number of harmful bacteria and pollutants being released into our open waters.”

A study on the Harlem river published in the Journal of Environmental Protection found that “phosphorus, ammonia concentration as well as fecal coliform, E. coli, and enterococcus levels increased significantly during heavy rainstorms.” These levels of bacteria in the water after a storm are well over EPA standards and can cause various bacterial infections in humans if exposed.

Heavy rainfall and resulting CSOs also lead to the increase in polychlorinated biphenyls (PCBs) in the City’s water. According to the EPA “PCBs are one of the most widely studied environmental contaminants.” They have been shown to cause cancer in animals and seriously affect their immune system, nervous system, and reproductive system. Epidemiological studies have also shown associations between PCB exposure and rare cancers in humans.

The New York City Department of Environmental Protection (DEP) has provided funds to engineers and architects in the attempts to prevent CSO occurrence and the environmental damage associated with them.

“[The DEP] have a lot of money to use green infrastructure, using plants and using landscape infrastructure as a way to collect rain water that falls, filter it, and let it infiltrate into the soil,” said landscape architect Tricia Martin. “The [DEP’s] capital investment projects are mainly concerned with the installation of bioswales, especially around where the big combined sewer overflows are happening.”

Unfortunately, capital investment projects are very expensive and time consuming, for example, the Croton Water Filtration Plant was initially supposed to be completed in 2006 only to be completed this year with total spending on it being $3.2 billion. The installation of bioswales is faced with challenges as well.

“Putting a bioswale in is not some easy task,” said Martin. “The goal for some of these watersheds is to put 500 plus wells in and its very hard to find 500 locations, you run into restrictions.”

Restrictions include encountering high water tables, high level bedrock, and toxic soil, which if used for a bioswale may result in toxic water overflows.

Other forms of green infrastructure include the installation of rain gardens to absorb rain water, and blue roofs, which the DEP states act to “create temporary ponding and gradual release of storm water.”

The alleviation of pressure from New York City’s outdated combined sewer system is far from substantial enough to completely eradicate the occurrence of CSOs and their associated harmful health effects, however, the implementation of green infrastructure is on the rise and its importance is being noticed by the public eye.