Break walls?

We are on a bridge in this picture, and I'm not quite sure what I'm looking at here. I don't know what purpose those piles of rocks serve. They may be a Bahrain version of a breakwall because you can see the tide rush in and out between them, or they may be designed to keep larger boats out. In the distance you can see a big ass ship. The water is so shallow here they must have dug a channel for these ships. You can literally walk out in the water in most places a good quarter mile before it goes over your head (so I hear.)