If you click on the vid the title is: Saylorville Spillway - 3-21-2007
And the description says: The outlet channel is a single circular concrete conduit, 22 ft. in diameter, located at the bottom of the west bluff. The control structure is located at the upstream end of the conduit and houses three gates, which have the capability of releasing a maximum outflow of 21,000 cubic feet of water per second (c.f.s.).
A quick google of the title reveals: Saylorville Lake - Wikipedia, the free encyclopedia
On the Des Moines River in Iowa in Polk County Iowa.