eli5 Why do some rivers have locks?


I understand (I think) why Canals have them, but why rivers

In: 4

Dams to maintain water level in the channel deep enough for boats to use, plus locks so boats can move from one section to the next. Also, turning a river into a series of lakes reduces the speed boats have to go to get upriver.

Usually so boats can get past dams. Think of the lock as a short little canal that bypasses the dam.

Locks on rivers essentially turn them into navigable canals. Without the locks, many rivers have rapids or short sections that cannot be navigated by ships / barges due to low clearance.

I keep seeing the word ‘dam’ and feel it should be Weir.

A dam stops the water flowing, a Weir is a way to keep the water level high, by letting the excess flow over the top.

They are there to allow boats to travel up and down the river. The river flows downhill, and if it’s too steep, the water flows in such a way that the water level will be too low in that fast moving section for boats to travel. The lock usually accompanies a dam or weir to raise the water level upstream, but the boat needs to use the lock to make that height transition. The only difference when a canal uses them is that it was planned out in advance, along with the rest of the canal, where as in a river we have to do some modifications.

Source: I live near a lot of locks