Right near the complex where I work, there is an unusual hydroelectric system on the Ottawa river. On either side of the main channel are large concrete canals with blocks of turbines. From those, high voltage power lines extend. In the middle of the river, there is a long arc of gates. These are to manage the degree to which water flows through the side channels, and the degree to which it flows over the uneven stone surfaces that were once natural cascades.
Since the water level in the river is high, there is pretty much always some degree of overflow venting through the gates. The little building you can see above them actually moves along the arc, raising and lowering gates. I am not sure if there are people inside or whether it is robotic, but everyone with an office on the south side of my building has a constant view of the whole installation. Those on the north side must content themselves with the fountain at a Gatineau casino.
Energy Ottawa operates two ‘run-of-the-river’ hydroelectric generating stations on the Ottawa River in Canada’s Capital. Run-of-the-river means the stations do not dam or interrupt the flow of the river—an important criteria for our recent certification under Environment Canada’s EcoLogo program.
Source
Chaudière Falls
Finally
They may not “interrupt” the flow of the river, but they did interrupt the river as concerned the first nations for whom the rapids was an important spiritual place.