Alaska Tidal Datum Portal
Unambiguous vertical datums in the coastal environment are critical to the evaluation of natural hazard vulnerability in support of local and regional planning. Appropriate tidal data must be considered in the siting, design, construction, and operations of development projects to ensure protection of human life, property, and the coastal environment.
Help update the Tidal Datum Portal, improve the National Spatial Reference System, and facilitate public access to Alaska benchmarks by collecting GPS data and making a contribution to the shared Online Positioning User Service (OPUS) database. DGGS has prepared a list of priority tidal benchmark sites in support of this effort and shared solutions from any NGS geodetic mark are always encouraged.
- About the Alaska Tidal Datum Portal
The NOAA Center for Operational Oceanographic Products and Services (CO-OPS) provides infrastructure and expertise for all verified tidal measurements and is the ultimate authority on tidal datums in the United States. NOAA’s National Geodetic Survey maintains the National Spatial Reference System (NSRS) that is used to relate tidal datums to geodetic datums. The minimal record of water level measurements and limited survey control in our state prevents the widely-used VDatum program from being available for most of Alaska.s coast. DGGS has identified a critical need to improve awareness and facilitate access to tidal datum information in Alaska during this interim period.
The calculator function and information presented on this site are provided as a convenience, values obtained on this site should not be used for rigorous emergency, planning or construction purposes. Because the relationships between local tidal and geodetic elevations can change with time, the most up-to-date measurement sources must be consulted, independent of this site, to ensure accurate transformations for these high-stakes applications.
- Frequently Asked Questions (FAQ)
- Alaska Tidal Datum Calculator
- Recommended External Resources
The development of this site was partially funded with qualified outer continental shelf oil and gas revenues by the Coastal Impact Assistance Program, Fish & Wildlife Service, and U.S. Department of the Interior. The views and conclusions contained herein are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. government.