New York City’s sewage system dumps billions of gallons of untreated wastewater into Bronx waterways each year, according to an investigative report released earlier this week by City Limits Investigates.  

The wastewater is a combination of untreated storm runoff and sewage, known as combined sewage overflows (CSO), that is ejected from 494 overflow pipes around the city into dozens of waterways, including the Bronx and Harlem rivers. The third largest overflow pipe in the city is at West 192nd Street on the Harlem River, alongside a dozen others along the northern Harlem River.

Because much of the city’s sewer system combines rainwater and household waste in the same pipe, even a tenth of an inch of rain can overwhelm the city’s 14 sewage treatment plants, spilling human waste, street litter and potentially toxic materials and bacteria into local waterways.

Mayor Michael Bloomberg’s ambitious PlaNYC 2030 proposal includes recommendations for reducing these outfalls, but clean water advocates say it doesn’t go far enough.

"One problem we see is that [the Department of Environmental Protection] has become focused on traditional ‘hard infrastructure’ solutions and has not embraced what we call ‘green infrastructure,’" said Walter Matystik, a Manhattan College professor and environmental engineer. "And people believe those solutions really need to get addressed."

The green solutions Matystik and other Bronx environmentalists would like to see are things like green roofs, rain basins, and porous pavement, which absorb water before it reaches the sewer system. Although PlaNYC includes a five-year tax abatement for green roofs, supporters of that strategy say the incentive may not be attractive enough to developers and landlords.

Environmental experts point to porous pavement projects like one in Seattle, where an absorbent sidewalk reduced stormwater runoff by 99 percent in two years. Other initiatives included in DEP plans to reduce CSOs include 800 new greenstreets, which convert paved surfaces into green space.  

While clean water activists are pleased to see green infrastructure proposals in the city’s plan, they’re frustrated with the city’s reluctance to implement them on a large scale. Rohit Aggarwala, director of the Office of Long-Term Planning and Sustainability, told City Limits Investigates, "What we did in the plan – we did it throughout – is we set goals that we considered to be ambitious but achievable." The plan is focused on trying to restore the most polluted city waters, he said.

"Newtown Creek, Flushing Bay, Paerdegat Basin, parts of the Bronx River-these are the last places in the city where it’s not even safe enough to go out in a rowboat," Aggarwala said.

The methods for cleaning up those waterways include a mix of old standbys and limited green pilots. Officials say the green infrastructure has not been tested in a large urban area like New York, but advocates dismiss that argument.

"There are alternatives that are adopted all over the country, so why can’t you do it in New York City?" said Karen Argenti, who chairs the water committee of the Bronx Council for Environmental Quality. In fact, the Environmental Protection Agency has endorsed green infrastructure as a cost-efficient way to protect waterways. The agency recommends approaches that infiltrate or re-use stormwater, such as rain gardens, vegetated swales, trees with basins that can collect stormwater, and green roofs, which absorb rainwater instead of channeling it through the gutter and into the sewer system.

At this stage, there is a small pilot proposed in Jamaica Bay, and Argenti said the Bronx River would be perfect for a model watershed project.

Instead, the city’s plan relies on traditional "end of pipe" solutions, like large concrete tanks to collect excess rainwater, and barriers and nets to catch debris and litter in the water. City officials have argued that the costs of implementing new solutions on a large scale are too high and would raise water rates beyond what New Yorkers can pay.

The concrete tanks the city builds are expensive and not efficient, critics say. The city currently captures only 72 percent of its wet weather flow, and Bloomberg’s plan calls for the city to capture 75 percent, a negligible improvement. A consent order signed by the DEP in 2004 requires that the city meet the 75 percent standard. Under those standards, the city is not in compliance with the Clean Water Act, which calls for a capture rate of 85 percent.

Another controversy underscored in the City Limits article is the failure to make city waterways swimmable and fishable. PlaNYC aims to make 90 percent of the city’s tributaries open for recreation, which advocates assumed meant both primary (swimming, kayaking) and secondary (boating) contact. In recent statements, the administration has revised that goal to make 90 percent safe for secondary contact. That’s a disappointment to water advocates, who have organized the SWIM Coalition to press for higher standards and better methods of reducing sewage overflows to make the rivers safe for swimming and recreation.

SWIM Coalition members are urging the DEP to test out some of the newer approaches to capturing water at the source and reusing it. Their efforts may benefit from a settlement announced last week by Attorney General Andrew Cuomo that directs over $7 million to the National Fish and Wildlife Foundation for projects to reduce storm water pollution of the Bronx River.

The funds come from agreements with Yonkers Racing Corporation and the cities of Yonkers, White Plains, Scarsdale and Greenburgh, all of which had been polluting the Bronx River with untreated sewage.  

This means there will be more money available for greener infrastructure and more low-impact development, said Teresa Crimmins, of the Bronx River Alliance and SWIM Coalition.  

Ed. Note: This article is the result of a collaboration between the Norwood News and City Limits Investigates. To obtain CLI’s full report,"Deep Trouble: New York City Faces its Silent Sewage Crisis," or to read a summary, go to www.citylimits.org.