flooded causeways

in the Isle of jersey today. it's quite lovely and nice here, breeze blowing off the ocean, houses a cross between British row houses and French farm houses. everyone quite friendly. Wanted to walk the shoreline and watch the ocean so have been doing that. decided to go see Castle elizabeth which looked quite interesting being connected to the land by a causeway that is flooded during high tide. You can walk to the castle, about a mile walk, when the tide is out and there is a huge amphibian truck for when the tide is covereing the causeway.
As I am walking out to the castle, one of the trucks comes back full of people. there are other people on the causeway walking towards the castle as well but when we get there, the castle is locked up tight and no notice. We ask a workman and he says the wind is too high for the boats. Didn't realize that he meant the big amphibian trucks. I hd thought that when I got out to the castle, if the water got too high or i got too tired, i'd buy a ticket for a ride back on the truck. So I wandered around for maybe 15 minutes total time from the time I reached the castle until I started back. Noticed that the water was now at the edge of the walkway where it had been several feet further back on the way out to the castle. the tide is moving fast. I stop a family that is busy splashing through about 6" of water that is already over the walkway. Have to take off my shoes to get through that part. I go to the amphibian boat place and he says by law they have to quit when the wind is guaged to be too high because it will push over their trucks. So had i not started back when I did, I might have been stuck until low tide because no boats were coming out there. Also found out that the tide goes over the walkway by several meters. Another 15 minutes and I might have been swimming back to the beach.