There are two low dams with locks along the Cher River in our village — there are 16 such locks between Saint-Aignan and Tours.
A lock in French is une écluse, and the houses where the lockkeepers lived are called maisons éclusières. The one in the picture below is not much more than a mile from our house.
In theory the Cher is navigable, and in centuries past it was used for the transport of merchandise. Then along came trains and trucks. I don't think all the locks are in working order these days.