Most marshes keep dikes semi-mowed. In many cases the only way to get from one dike to another is walk/RTV on the top. The sides just grow all year long. Unless there is a trunk for water flow it can be like a tunnel.
Small birds (here a Grackle) and Dragonfly’s love to perch on the sides.
Unfortunately there can be a dozen Storks right on the other side and it’s impossible to get a photograph.
Bear Island, South Carolina.