The Lower Hudson River is a tidal, urban estuary that changes dramatically from season to season, and even day to day.
Twice-daily tides every six hours rise and fall, mixing salty ocean water from the harbor with the fresh currents pouring down from the source upstream. This brackish mixture provides critical inshore habitat for hundreds of species of fishes, crustaceans, mollusks, and many more creatures.
To monitor the water quality and ever-changing conditions, the Park maintains in-water devices called sondes that continuously measure and upload data to the internet to provide a real-time feed of river conditions such as temperature, salinity, pH, and the like.
The Park also conducts weekly surface-water pathogen contamination sampling as part of the Community Water Quality Testing Program, that provides boaters and recreators with high frequency, site-specific water quality data to inform safe recreation choices during the warmer months.
Learn more about the Park’s water quality monitoring work below!