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Water Quality

Water quality problems in the Bronx River are largely caused by infringements in the riparian corridor, loss of wetlands, reduced base flow, sedimentation, channel aggradation, floatable garbage, diffuse waterfowl and pet waste, stream bank erosion, and runoff from impervious surfaces and other point and non-point sources of pollution, including CSO (ACOE, 1999). Throughout the river’s 21.5 mile-long freshwater section (including Westchester), storm water from parking lots, sidewalks, roads and roofs flow directly into the Bronx River through more than 100 discharge pipes (Main, 2003). Because this water enters the river through pipes instead of the ground, it is warmer and carries contaminants and sediments picked up from the impervious surfaces over which it originally flowed. These pipes also often carry additional wastes from illegal connections to residential sanitary systems, gas stations, Laundromats or other small industries.

In the Unified Watershed Assessment for 1999 and 2000, the New York State Department of Environmental Conservation (NYS DEC) rated the Bronx River Basin as a category 1 watershed—the lowest of three ratings (NYS DEC, 2005). Category 1 watersheds do not meet, or face imminent threat of not meeting, clean water and other natural resources goals and are in need of restoration. All sections of the Bronx River are listed on NYS DEC’s Final 2004 Section 303(d) List of priority water bodies (NYS DEC, 2004A). These are priority waters in New York State identified for total maximum daily load (TMDL) development and do not support appropriate uses (NYS DEC, 2004B). In this listing, the problem parameters cited for the Bronx River are DO and fecal coliform. Healthy aquatic flora and fauna require a minimum level of DO in the water. When oxygen is scarce, the river’s capacity to sustain life is limited. High levels of fecal coliform, a bacterium that can cause human health problems, triggers state and federal regulations that preclude certain uses for the water that include drinking, swimming or even bodily contact.

Water quality in the Bronx River varies according to location and time. To test water quality NRG has measured many variables including both characteristics of the water itself and of the organisms living within it. Commonly measured criteria include dissolved oxygen, fecal coliform, turbidity, and pH. Benthic monitoring has also been used to determine water quality.

Water Quality Monitoring Work

Many organizations regularly monitor the water quality of the Bronx River. To view individual monitoring programs follow the links below. Much of the data from these programs is available for download on the left sidebar.

Section Title Source Year
All Bronx River Stewards Water Quality Monitoring Bronx River Alliance 2004-Present
All RiverKeeper Water Quality Monitoring (download in excel) RiverKeeper 2000
All Urban Riparian Wetland Monitoring - Benthic Invertebrates NRG 2002-2004
Parkland Water Quality Baseline Data ACOE 2005
Parkland, Botanical Garden/Zoo Turbidity (Total Suspended Solids) NRG 2003
Parkland, Botanical Garden/Zoo, West Farms Fecal Coliform Concentration HydroQual 2000-2001
Botanical Garden/Zoo, Estuary Water Quality Baseline Data Lehman College 2002-2005
West Farms, Estuary Water Quality Baseline Data NRG 2005-2006
West Farms, Estuary Pollutant Loading Model NRG 2004
Estuary Fannie Lou Water Quality Monitoring (download in excel) Fannie Lou Hamer School 2001
Estuary Water Quality Baseline Data (download in excel) HydroQual 2000-2001

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