No disrespect intended on explanation of hydro, sit-rep. Just figured some readers may not know that.
i do the same thing sometimes but that was teetering on the edge lol...
I am actually surprised they dont use more tunnel type turbines laying on the bottom of the rivers like some countries are using utilizing tide flows. Many of the great lakes rivers are plenty deep enough to not interfere with shipping.
for description purposes I’ll use an exaggerated hourglass shape as the tunnel. larger opening to a reduced sized turbine area for the Ram effect, and then from the reduced sized turbin area to a larger exit area for a suction effect... I think that would cause enough pressure to make a few watts of juice!! Especial in areas like where Lake Huron first drains into the St. Clair River. Current is very fast with thousands of GPM