Characterization of Stormwater Runoff from the Elevated Highway at Pier 5

Stormwater runoff from roadways introduces metals, salts, oil and grease, and other organic contaminants that can adversely affect the water quality of the receiving waterbody, thereby diminishing the health of the local ecosystem and limiting its recreational use. The Harlem River in New York City currently receives direct untreated runoff along the eastern bank (Bronx County) from portions of Interstate 87 (I-87; Major Deegan Expressway) through storm drains in the street below. According to the New York State Department of Environmental Conservation (NYS DEC), the Harlem River is classified as a Class I saline surface water, indicating that the NYS DEC has determined that its best use is for secondary contact recreation and fishing, as well as being suitable for fish propagation and survival. A primary water-quality concern is numerous combined sewer outfalls (CSOs) that discharge along the river. In addition, stormwater runoff along the paved shorelines and elevated roadways contribute to poor water quality in areas such as those along Pier 5.

[top left] One of many downspouts that divert stormwater from the deck of the elevated Interstate-87 to the sidewalks below. [right] Storm drains along the sidewalk catch runoff from the downspouts and roadways and sends it underground towards the Harlem River. [bottom left] Storm drain outfalls along the Harlem River. This drain is less common in NYC as most of the City's stormwater is captured in the combined sewer system where it is transported to one of 14 wastewater treatment plants.