HARLEM — It took decades for the water quality in the Harlem River to improve, but the river remains “impaired,” meaning it still fails to meet state and federal guidelines, a government report says.
A report released Tuesday by the U.S. Geological Survey touted the improvements of the river’s water quality since passage of the Clean Water Act in 1972, but said in a first-time analysis of the river data that “the concentrations of dissolved oxygen and fecal indicator bacteria do not consistently meet standards for good ecological health.”
The report found that over the past 20 years other healthy water indicators have improved, including concentrations of ammonia and suspended solids like sewage, which can be filtered out by wastewater treatment plants.
However, the river is still classified as “Class I” under state Department of Environmental Conservation regulations, which means the river is “impaired.”
An “impaired” designation means there is still a presence of pollutants in the river and the surrounding communities cannot fully use the river as a natural resource, specifically for recreational activities such as swimming, the report said.
Since the 1700s, the report said, people have been using the river for shipping and waste disposal, which severely affected overall water quality.
And although recreational boating and fishing are permitted, certain shellfish caught should not be eaten, the report warned.
“The actions that have been taken the past 40 years have resulted in significant improvement to the river’s water quality,” said Shawn Fisher, a USGS hydrologist and author of the study.
“Even with the changes, though, the river remains on the impaired waterways list…It’s likely to remain on the impaired list until the potential for sewage discharge into the river through combined sewer outflows has been eliminated, and the riverbed sediment is remediated.”
Fisher added that a “comprehensive assessment” would be needed to measure current concentrations of pollutants prior to the clean water legislation, such as metals, to identify which contaminants remain in the river, how they can be safely removed and prevented from entering in the future, the report said.
A city Department of Environmental Protection official told DNAinfo New York the agency is taking steps to improve the water quality and prevent further erosion.
“DEP has made significant improvements to the water quality and is currently attaining primary contact standards for dissolved oxygen and looks to be very close in attaining the primary contact standards for fecal coliform,” the DEP spokesperson said.
“There is expected to be a reduction in (combined sewer overflow) and a corresponding reduction in pathogen concentration within the Harlem River when a long-term headworks project at the Wards Island (Wastewater Treatment Plant) is completed.
“In addition, DEP is currently preparing a (combined sewer overflow) Long Term Control Plan that will assess additional green and gray alternatives to further reduce (combined sewer overflow) discharges with the goal of attaining primary contact standards for pathogen and dissolved oxygen."