Hudson River Salt Front Data

Science Center Objects

Tide stage, specific conductance, water temperature, and freshwater inflow at selected Hudson River (New York) gages updated every hour. Water temperature and specific conductance are measured at a depth of 10 feet below NGVD 1929 (mean sea level). These data include PROVISIONAL DATA subject to revision.

This information has been made possible by funding from the U.S. Geological Survey Cooperative Water Program and National Streamflow Information Program and New York City Department of Environmental Protection, New York State Department of Environmental Conservation, New York State Department of Health, Hudson Valley Regional Council (representing Dutchess, Orange, Putnam, Rockland, Ulster, and Westchester Counties), the Hudson River-Black River Regulating District, and the City of Poughkeepsie, NY.


Hudson River Estuary:

  • Current salt-front location in the Hudson River (map,

    table, tab delimitted). Location, in river miles above The Battery, New York City, is a daily value for the most upstream location (at high slack tide) for the previous day. The salt front is defined as 100 mg/L chloride concentration; and measured in the field as a specific conductance of 510 microsiemens per centimeter at 25 degrees Celsius (see conversion chart).

Streamflows and Reservoir Levels:


Historical Event Information:

To view and print the postscript (.ps) files from your browser, download, (free), the GSview utility.

USGS Hudson River Salt Front Study (Project Description, Map, etc.):