What does MLLW stand for in tidal references?

MLLW stands for Mean Lower Low Water, which is a standard reference point used in tidal studies and navigation. It represents the average of the lower low water heights observed over a specific period, typically 19 years, capturing the lowest tide level in a tidal cycle for any given location. This reference is crucial for mariners and navigational purposes as it helps determine safe navigation depths and the vertical clearance needed for various vessels.

Understanding MLLW is particularly important in coastal areas where tides can significantly impact water levels. By using MLLW as a baseline, sailors can avoid grounding and ensure safe passage, especially in shallow waters. The other options provided do not accurately define MLLW, as they either use incorrect terminology or conceptually misrepresent tidal references.