Low Tide Festival 2011

This year, the Low Tide Festival will be held from 10AM to 3 PM, at Point Robinson Light Station and Park. The tide this year is at its lowest at approximately 12:15 PM, and will e at 2.6 feet below datum.

So what does it mean that the water level at Point Robinson will be more than two feet below datum? Over the years that tide levels have been recorded by hydrographic agencies, an average level for low tide has been determined. That low tide average level is shown on the nautical charts, and in several other places used by professional seamen. It be enough to say that when the tide levels are below that average, called datum, a minus tide is recorded. And that manifests itself in a lot of beach out at Point Robinson. That is the result of all that datum stuff-the chance to see creatures and features that would not otherwise be visible.

I use Dot’s Fishing Guide Tide Tables, available at many places on our Island. Although I am not a fisherman, I like the format in Dot’s. It is compact, has an enormous amount of information, and the use of the tables can be learned by anyone. The only caveat I add is to not only look up the state of the tide in the main tables, but also look to see if there is any correction factor for your particular location.

The theory of tides is simple in concept, and very complicated in the derivation of the tables. The tides happen because the sun and the moon exert a gravitational pull on the earth. When the sun and the moon are in line, and on the same side of the earth, their gravitational pull, especially of the moon, is additive. That is when the tides are the lowest, and the closest high tides are high. And if the moon is at the same time closer to the earth, that makes for even higher and lower tides. And without getting into the theory, leaving something for you to figure out, there are no tides on our Great Lakes. However, wind can move the water in the lakes, especially Lake Erie, from one side of the lake to the other, causing as much as a two foot drop in water level on the upwind side.

So come and join us on Saturday, 2 July, for a day filled with exploration, guided by your neighbors in their role as beach naturalists. There will be displays, I will be giving tours of the lighthouse, food, and the chance to expose the youngest of our citizens to Good Beach Behavior.

Written at 8 bells of the Morning Watch by Captain Joe, President of the Keepers of Point Robinson