Posted by BCH DIVR on July 02, 2003 at 21:58:29:
In Reply to: Beach Diving Conditions and Tides posted by Andy on July 02, 2003 at 11:34:17:
I have often heard the high tide/good visibility lore but there is neither empirical evidence nor rational thought to support it. The reasoning was that "cleaner" water from the deep improved the viz but a quick calculation indicates the amount of dilution will have essentially no effect on the visibility. I also put the question to this board last year and no one wrote that they noticed better viz at high tides.
The best beach dive viz I saw was 13 years ago at El Matador (usually a consistent 10 footer) when we had 60 to 100 feet of visibility (no joking!). This dive was at the end of a week of Santa Ana winds and there was absolutly no surf. I believe it was the lack of surf as well as the off season for plankton that produced the outstanding viz, though upwelling of "clean" water cannot be ruled out.