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Continuously Operating Reference Station Program

National Water Level Observation Network

Center for Operational Oceanographic Products and Services

National Geodetic Survey


Observing Land Motion and Water Level Change – Same Time, Same Place

A CORS station

The CORS at Battery Park, NY. Stations within the CORS network enable NOAA and others to monitor the smallest changes in the Earth environment because they provide significantly more accurate vertical and horizontal positions than could ever be obtained from a single Global Positioning System unit or geodetic markers.

A Continuously Operating Reference Station (CORS) now sits next to one of the country’s longest standing tide gauges at Battery Park in New York City, New York.

The tide gauge is one of 175 water-level stations that make up the National Water Level Observation Network (NWLON). NWLON stations, managed by the Center for Operational Oceanographic Products and Services, are the foundation for NOAA’s tide prediction products. NWLON stations also serve as controls in determining tidal datums for coastal activities.

Water-level station at Battery, NY

The tide station at Battery, NY, is one of 205 water-level stations operated by NOS around the country. These stations are part of a comprehensive water-level monitoring network.

The CORS network comprises a collection of more than 1,350 stably mounted receivers that collect signals from Global Positioning System satellites around the clock. The National Geodetic Survey processes these signals to accurately track the three-dimensional location of CORS sites over time.

Co-locating the NWLON station and CORS at Battery Park will enable NOAA to relate water-level change with land motion to better anticipate flooding related to  land subsidence (sinking), earthquakes, sea level rise, storm surge, and other natural phenomena.