Urban Waters Federal Partnership—Bronx and Harlem River Watersheds (New York, N.Y.)

Science Center Objects

The Harlem and Bronx Rivers provide ecological and social resources in an intensively urban area. Connecting people to rivers requires clean water—the USGS is helping to assess the efficacy of green infrastructure to improve the quality of stormwater that flows into the rivers.

RCSP intertidal area post storm.

Roberto Clemente State Park intertidal area, post storm.

Living shorelines, parks, and access to water add to quality of life and provide a breath of fresh air in densely urbanized areas. The New York City Department of Parks and Recreation (NYC Parks) is committed to implementing green infrastructure to keep contaminants out of the Bronx and Harlem Rivers. The USGS is partnering with NYC Parks to evaluate the effectiveness of different green infrastructure systems in removing stormwater-related contaminants in areas of existing and proposed parks.

Harlem River Street tree monitoring

Harlem River Street tree monitoring.

At Roberto Clemente State Park, USGS is working with the NYC Department of Environmental Protection (DEP), and Interstate Environmental Commission (IEC) to collect upriver, storm, and non-storm water samples to determine how effective a green roof, the intertidal zone, and a bioswale are at removing contaminants in stormwater runoff. Contaminants of interest include organic contaminants, metals, nutrients, and indicator bacteria.  The USGS also is assisting in the measurement of these contaminants along Depot Place, Bronx, the site of the proposed Bridge Park South, at which NYC Parks is exploring the possibility of living shorelines and access to the water from the park. As part of this effort, the DEP has installed a continuous water-quality monitor at Roberto Clemente State Park to support the NYC Parks Harlem River Watershed Management Plan and overall monitoring of the Harlem River.

Together, USGS, NYC Parks, and DEP are assessing whether street trees newly planted along the Harlem and Bronx Rivers can help capture stormwater runoff, diverting it away from the combined sewer systems. USGS has been monitoring daily soil moisture values in five pairs of trees—each pair has one tree with a pit guard and one without—that are located within the same city block. USGS will be installing piezometers to collect soil water samples that will be analyzed for contaminants, and DEP will be monitoring groundwater levels. The results will be compared to water quality of untreated storm runoff and soil water from compacted soil under mature trees.

An additional activity is the monitoring of the effects of a newly installed geothermal well on surface-water and groundwater quality. The well, located at the Bronx Riverhouse, will be used to heat and cool the NYC Parks and Bronx River Alliance outreach building. Water will be pumped from deep in the aquifer (1,250 feet below surface) and discharged in the shallow annular space around the well (10 feet below surface). Groundwater will be analyzed for major ions, trace elements, nutrients, volatile organic compounds (VOCs), a range of isotopes, and a range of physical properties. The question of interest is whether changes in the chemistry and physical properties of the groundwater caused by pumping will affect the geothermal equipment. For example, will the aeration of deep groundwater, which contains little dissolved oxygen, when it discharges at shallow depths cause rusting? The initial results, collected prior to the activation of the geothermal system, will serve as a baseline for comparison with later samples to be collected after the geothermal system is activated.

Transects across and along the Harlem River are being conducted to assess the spatial distribution of the fecal indicator bacteria Enterococcus, which is used by health officials and City managers to assess beach conditions for recreational uses. In cooperation with the U.S. Environmental Protection Agency (EPA), both storm and non-storm events will be sampled. In additional, microbial source tracking methods will be used at select sites and depths for analysis at two USGS microbiology labs to better understand differences in pathogen presence and transport. 

The projects on the Harlem and Bronx Rivers are in cooperation with the New York City Department of Parks and Recreation, the New York City Department of Environmental Protection, the New York City Department of Design and Construction, the Interstate Environmental Commission, and the U.S. Environmental Protection Agency.
 

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More about other Urban Waters Federal Partnership projects