Standards for establishment of local tidal datums.

(1) Unless otherwise allowed by this part or regulations promulgated hereunder, a local tidal datum shall be established from a series of tide observations taken at a tide station established in accordance with procedures approved by the department. In establishing such procedures, full consideration will be given to the national standards and procedures established by the National Ocean Service.

(2) Records acquired at control tide stations, which are based on mean 19-year values, comprise the basic data from which tidal datums are determined.

(3) Observations at a tide station other than a control tide station shall be reduced to mean 19-year values through comparison with simultaneous observations at the appropriate control tide stations. The observations shall be made continuously and shall extend over such period as shall be provided for in departmental regulations.

(4) When a local tidal datum has been established, it shall be preserved by referring it to tidal bench marks in the manner prescribed by the department.

(5) A local tidal datum may be established between two tide stations by interpolation when the time and mean range differences of the tide between the two tide stations are within acceptable standards as determined by the department. The methods for establishing the local tidal datum by interpolation shall be prescribed by regulations of the department. Local tidal datums established in this manner shall be recorded with the department.

(6) A local tidal datum properly established through the use of continuous tide observations meeting the standards described in this section shall be presumptively correct when it differs from a local tidal datum established by interpolation.

(7) The department may approve the use of tide observations made prior to July 1, 1974, for use in establishing local tidal datums.