When driving around Western NY this summer I stopped by to see the Lock at Seneca Falls on the CS (Cayuga-Seneca) Canal. This is also run by the state and similar in running to the Erie Canal locks to the direct North. Here is the Upstream end of the lock with the gates closed and the lock full at the moment. The tower to the left is an emergency drop gate in case there is a breach they can quickly drop the massive steel gate and shut down the water flow.
Click images for a larger view:
They let you walk right alongside the lock on this steel walkway and below is a very well kept park area you can eat lunch at.