Analytical Solution for the Amplitude Ratio Method for Determining Mean High Water in Tidal Regions

In areas that are subject to tidal waters, projects such as bridge construction and property boundary location require the determination of the water level or water datum. Of the different water data that can be established, the mean high water (MHW) is of prime importance. To establish the MHW line at a project site, it is necessary to either make long-term (19 years) continuous tide observations or to perform simultaneous short-term tide observations at points in the vicinity of the project and at a tidal control station. Of the three short-term observation and computation methods for determining the MHW, the amplitude ratio method is applicable in most general circumstances. The current computation procedure of the amplitude ratio method utilizes graphic means to determine the tide amplitude. A new analytical solution for this method was developed using least squares principles. The advantages of the proposed solution are simplicity of computation, suitability for automatic data processing, and usability even with incomplete observation data sets.