What is the generally recognized average used to establish the Mean High Tide marker in Texas?

The Mean High Tide marker is established based on an extensive analysis of tidal data to accurately reflect the average high water line over time. The generally recognized average used for this purpose is 18.6 years of tidal data. This lengthy duration accounts for the cyclical nature of tidal patterns, including variations caused by astronomical factors such as the moon's influence and the shifting nature of coastlines.

Utilizing an 18.6-year period allows surveyors and coastal managers to obtain a representative average that smooths out anomalies caused by shorter-term events such as storms or extreme weather conditions. This long-term approach provides an accurate understanding of tidal behavior and is essential for legal and environmental applications, including land use and property boundaries.

Other options range from shorter periods, which would not capture the full span of the tidal cycle's influences in a meaningful way, potentially leading to misinterpretations of the mean high tide line. For example, a 12-month or 5-year average would be insufficient for capturing long-term trends, while a 30-year average could provide more data but exceeds the typical standardized approach for determining the Mean High Tide in Texas.