yes there would be large rock pools but most of it would be gone, also to my knowledge its not a high\low tide as we know it, it all depends on the ammount of rain the surface is having that leaks into "our" rivers which controls the ammount of water in the "great lake", but then to me it seems to screw with the harbour a bit as the harbour maps show what it looks like when there has been alot of rain and the "great lake" has reached is usual highest. Not considering that average rainfall would cause the lake to be much lower, and then very low rainfull to be not even be anywhere near it.
:\ All I can think is during periods of low tides the land is used for farming perhaps, as i would expect it to be more a seasonal thing, lots of rain during winter, not so much in summer.
EDIT: minetus, I would think that the Klyros would make artificial valleys for low tide made out of stone to control the river (would support the farming idea), also if the tides are seasonal valleys would change alot, as the "great lake" would alter them during high tide.