海角大神

Green solutions for New York City's overflowing sewers

Techniques such as more trees and porous pavement can reduce runoff that fouls the city's waterways.

In late July, Harlem residents held their noses as millions of gallons of untreated sewage water flowed straight into the Harlem and Hudson Rivers because of a sewage plant fire. On the hottest day of the year, precious beaches and water areas were off limits, too toxic to swim in, as a repair team took shifts working in the heat to fix the plant.

But the crisis was more than just an isolated incident; it was symptomatic of a larger, structural problem in the way New York City 鈥� home to 8.5 million people 鈥� deals with its residents鈥� liquid waste.

Each year, 27 billion gallons of raw sewage are dumped into the New York City harbor, making sewage, or more specifically, the city's inability to process waste water, the largest source of water pollution in the city. This dumping is caused by combined sewer overflows that occur when the sewer system becomes overloaded by heavy rain on top of normal sewage flows. Overburdened city infrastructure is simply not capable of handing so much water.

The solution to this problem may lie in what is known as 鈥済reen infrastructure.鈥� Green infrastructure, according to the and , the city鈥檚 sustainability initiative, includes 鈥渁dvanced tree pits, porous pavements and streets, green and blue roofs.鈥� It is essentially anything that is built in to the city鈥檚 currently existing infrastructure that makes systems, like sewage collection and treatment, run more smoothly.

Large-scale, industrial solutions, such as 50-million underground sewage storage tanks, are simply not affordable given New York City鈥檚 budget constraints. And the return on investment for these tanks is diminishing rather than growing according to PlaNYC. Therefore, other solutions must be taken seriously.

With green infrastructure, the city aims to reduce combined sewageo utflows by 鈥渕anag[ing] runoff from 10 percent of the impervious surfaces in combined sewer watersheds through detention and infiltration source controls.鈥� One tangible way to do this: the campaign, which is planting trees throughout the city not only to provide shade, but also to create more treebeds that absorb rainwater.

But to many sustainability activists, the city鈥檚 green infrastructure plan is just a stop-gap measure, well-intentioned but too centralized and bureaucratic.

The approach of the coalition differs. The coalition views stormwater as a resource, rather than a waste. It wants to improve water quality through 鈥渘atural, sustainable stormwater management practices in our neighborhoods,鈥� according to its website. It has more than 70 member organizations working on infrastructural water issues in New York City.

After the recent North River sewage plant crisis, S.W.I.M. released that the level of pollution in the Hudson River was much higher than the Department of Environmental Protection (DEP) had announced.

鈥� is one of our member organizations,鈥� explained Kate Zidar, the coordinator of S.W.I.M. 鈥淭hey sampled in the middle of the river and near the shoreline; they did a comparative grid. It鈥檚 not totally clear to me how DEP tests; typically they test midstream. Riverkeeper found the pollution because they looked for it.鈥�

What does this say about the DEP鈥檚 efforts to fulfill their responsibilities?

鈥淏oth the testing and the notification that is based on that testing is insufficient. It doesn鈥檛 meet their required duties,鈥� Ms. Zidar said.

Zidar is critical of the DEP鈥檚 plans for stormwater management as well.

鈥淭he DEP is kind of creating their own definition of green infrastructure, which is confusing for people who have been in this field longer than they have,鈥� she said. 鈥淭hey are using the term 鈥榞reen infrastructure鈥� to refer to what鈥檚 really stormwater detention.鈥�

Detention refers to a process by which stormwater is held and then later released, decreasing the volume of water in the system. But retention, by contrast, is when water is retained and utilized. Retention, not detention, is what green infrastructure is based on, according to Zidar and others in the S.W.I.M. network.

鈥淭here are major flaws in the [city's] plan,鈥� Zidar said. 鈥淲e鈥檙e trying to make this better.鈥�

In addition to the S.W.I.M. coalition, individual sustainability activists are taking matters into their own hands. One technology designer, Leif Percifeld, has invented a way for the NYC sewer system to 鈥渢alk back鈥� to New Yorkers, alerting them to storm events and system overflows.

Using Open Source coding and software, Mr. Percifeld made a sensor that can detect rising water levels and send text messages warning recipients not to use water at home. His next step is getting into the city鈥檚 sewers to install the sensors 鈥� no easy task, given that he鈥檚 doing it illegally and undercover. With the help of a , a flashlight, and some , however, he is determined to make it happen. Anyone can sign up for the alerts through the website.

Percifeld is acting to solve this problem as a citizen scientist, tackling a citywide infrastructural problem through grass-roots means: crowdfunding on a website to pay for materials, developing the technology on his own, and entering sewers without authorization.

Another citizen scientist team, , is embarking on a year-long research project to evaluate the potential of urban farms to become part of a city鈥檚 green infrastructure. Like Percifeld, Tyler Caruso and Erik Facteau are working at the grass-roots level, collaborating with people in their social network and employing their own know-how and resources to tackle the problem of burdened water systems. Caruso and Facteau would like for their research to nudge city officials into providing further support for urban agriculture.

Cleaning up the city鈥檚 waterways is a dirty job. But solutions are evolving from all levels 鈥� official citywide plans and grass-roots, collaborative efforts amongst concerned citizens. Moving forward, it will be vital that the lines of communication between all these actors are kept open so that affordable, sustainable solutions can go into effect as quickly as possible.

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