Highest Astronomical Tide Line? Pacific County Shoreline Master Program Update Questioned

60 days to appeal Pacific County's SMP update, starting from January 17.

HATs off to the County Commissioners
January 17 Pacific County's SMP update was accepted. Some are now wondering how it was that one area of Pacific County's shoreline is defined as being at the "Highest Astronomical Tide" (HAT) line, and other areas are the Ordinary High Water, typically defined as the average of the highest of the high tides. Two Districts, those represented by Commissioners Ayers and Rogers, do not have that definition (HAT) adapted.

Shifting lines in the sand, shifting times.
The difference can, in some cases, be very significant, impacting where buffer lines are set and developments occur. Using the Department of Ecology's definition, the line is towards the water, in essence providing upland owners a larger parcel and buffers beginning further towards the water. In the case of the HAT, that line is where the highest tide of the year (or perhaps decade, or maybe within the National Tidal Datum Epoch period - an 18 year period of time) is. How one determines that is a surveyor's dream, as they will have to spend hours researching the topography of the land and the cycles of the moon/sun to determine just where that line is. Or wait all year for the highest tide (assuming it is an annual event they are talking about).

Making waves in a storm.
To compound the problem, there is an issue over whether the line being pushed even higher by waves needs to be considered. If one is able to determine the HAT line, what happens if there is a storm which shows the water is actually rising higher? And what if there happens to be a low pressure event offshore which coincides with the HAT, in turn, pushing that line even higher?

Get involved. The seemingly arbitrary adoption of shorelines in two districts being defined as the Highest Astronomical Tide is going to cause Pacific County and property owners challenges as they move forward.

(SMP change from Dan Driscoll, Oysterville Seafarms at 360-244-0736)