noaa.gov
Datum Updates
Tide and water level datums are standard elevations used to reference water level heights and depths. Each type of datum represents a unique phase or behavior of the water along the coast or in the Great Lakes. CO-OPS and its partners are currently in the midst of two large-scale datum updates for the National Tidal Datum Epoch (NTDE) and the International Great Lakes Datum (IGLD).
To obtain datums for a specific location, please visit the CO-OPS Datums Station Selection web pages.
National Tidal Datum Epoch
The NTDE is a specific 19-year reference period over which water level observations are taken to determine Mean Sea Level and other tidal datums (e.g., Mean Lower Low Water). The NTDE has historically been updated every 20-25 years.
International Great Lakes Datum
The IGLD is a common reference system used to measure water level heights throughout the Great Lakes, their connecting waterways, and the St. Lawrence River System. The IGLD is updated every 25-30 years.
CO-OPS water level station 8465705 in New Haven, CT. There are over 200 stations like these across the nation collecting continuous water level data. Their data will be used to calculate the new datums.
Website Owner:Center for Operational Oceanographic Products and Services
National Oceanic and Atmospheric Administration
National Ocean Service
Privacy Policy
Disclaimers
Take Our Survey
Freedom of Information Act
Contact Us
NOAA WebsiteTides & Currents HomeHome (current)OverviewNavigation ServicesCoastal HazardsMapping and ChartingStrategic PlanContact UsTides and Water LevelsCurrentsPORTSĀ®Harmful Algal BloomsSea Level and Coastal Flooding InformationMeteorological and Other Oceanographic DataCoastal and Great Lakes Conditions ForecastCO-OPS PublicationsCO-OPS Field LibraryGIS and Web ServicesDatum UpdatesNewsTides & Water LevelsCurrentsFor Teachers and StudentsTides and Currents GlossaryFAQ
Home/Products