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  4. I’ve been given mean high water springs (MHWS) and highest astronomical tide (HAT) predicted Tide Levels by another source. They don’t match up to those in the Coastal Flood Boundaries. Which should I use?

I’ve been given mean high water springs (MHWS) and highest astronomical tide (HAT) predicted Tide Levels by another source. They don’t match up to those in the Coastal Flood Boundaries. Which should I use?

Created: 03 October 2019 Updated: 03 October 2019

The 2018 updated dataset includes HAT and MHWS tide levels. These are based on interpolated levels at locations between NTGN sites and should be used for flood risk management purposes only. These levels should not be used for navigation purposes.