Following on from underwater walling, this short video shows the newly walled section of fort stretching into the ocean. A surface perimeter has been built to prevent ocean waves from splashing water into the drained area which was preventing the east side pumps (moved slightly to the right) from draining the pool properly.
Important: If the movie appears blank or fails to play it is because it was recorded using a corrupt version of Dwarf Fortress. This is a known bug and is reported in the tracker, bug 2489. The DFMA administration is in the process of cleaning up these movies from the site; and hopes bay12games will fix the game functionality soon.