I would try to keep the fences away from the water just because it's a hazard to the fence. If the fence gets in the water, it will just ground out, and with a dead fence your goats can come and go as they please. It's not like dropping a radio or some other appliance in the bathtub. We had a bit of a flash flood a few months ago and everything was under water, including most of our electic fences which were on a very, very hot 100-mile plug-in Zareba charger, and no one got electrocuted.