Tide datums are essential yet often overlooked tools in marine navigation and coastal management. They serve as reference points, or baselines, from which all water depth measurements are made. A common datum used is Mean Sea Level (MSL), the average sea level over several years, which provides a stable platform for measuring tides, charting nautical maps, and assessing coastal construction.

Different datums are used for various purposes. For instance, Mean Lower Low Water (MLLW) is typically employed for navigation charts in the United States, as it represents the average of the lowest low tide recorded each day. On the other hand, coastal engineers might use Higher High Water (HHW) when designing sea defenses to ensure they withstand the most extreme high tides.

Understanding and choosing the correct tide datum is crucial because the difference between two datums can be significant. Using the wrong datum in measurements or construction can lead to errors, potentially causing boats to run aground or inadequate coastal defenses.

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