Do your research before getting into rivers. My local river has several gauges and hotlines you can call to get dam releases. They also have a chart of the water release amounts and if you could paddle/float/canoe/kayak etc. It even has a turbidity gauge that will show you if any harmful bacteria is present, we have issues with fertilizer runoff and e-coli. It's a rather mundane river in an area not as known as Glaci…
Acquaintance did some suburban kayaking and didn't see a 3ft drop (some kind of dam or culvert under a bridge) until too late. The fluid mechanics of that drop are such that there is a vortex at the base that makes it difficult to get out. He was able to stand but just barely - scary to think how close a call that was in a pretty innocuous looking setting.
Low head dams are the drowning machine, and they can look very safe and simple.