The large wood and steel rectangles before you are the walls of temporary dams.
They are designed to be placed by crane at either end of the stone locks to your right. —- This allows the locks to be closed off, the water pumped out, and repairs made to the lock doors.
In the past, mud built up at the base of the doors, wood rotted, and metal control pieces bent. At the moment, repairs are needed to the "wicket gates". — These are the small metal louvers at the bottom of the doors that regulate the flow of water into (and out of) the locks. This determines level of water in the locks, so that the doors can be easily moved.
These are cumbersome and heavy. Moving them long distances is impractical. They are stored here in anticipation of reopening the canal. This work is dependent, however, on costly restorations to the railroad bridge behind you.