There is a fresh water lake near Pascagoula, Miss. with similar rumors. It rises and falls with the tides too.
I am suprised that I am suprised to discover that fresh water enters the oceans gulfs and seas from springs at the bottom. We all should have realized that with the dry land being far higher than the ocean floor, that the veins of water that supply our wells and then flow on to the next well, would eventually bubble up, just as surely as the rivers, branches and creeks eventually flow onto the surface of those same bodies of water.
LOL! Now that we know , how the heck are we going to use this knowledge for our benefit?