Drain gates. So that’s what those are I see.
Yes drain gates just like paddocks with our Dutch brethren. Usually a simple sluice gate of nothing more than a piece of plywood in a frame that can be raised and lowered. If bit rain water filling the paddies it’s pumped in from rivers in East Texas either way those gates must be closed to flood the fields. Even if not stocked most of the former paddies are loaded with crayfish aka mudbugs spring rains bring them out of their borrows and into traps if you set them in the flooded fields. In that case yes we will eat ZZZZZ bugs properly boiled in oh so salty water with lemons onions sausage potatoes and corn. Have a good dirty rice on the side and some Abita beer by the keg.