These photos show an interesting activity taking place. Notice in the last photo that a tow boat is just entering a lock. In another photo, the lock is empty. In the 2nd to last photo, a set of barges has already exited the lock. These photos were all taken within a minute or two of each other, so these conditions existed at the same point in time. What is going on? The barge tow is too long for the 600 foot lock. As a result, the tow was broken into two pieces. One set of barges was locked through, then tied up below the dam. The second set is now waiting to enter the lock. Once they pass through the lock, the tow will be joined back together for the trip down to Lock & Dam #25.