Between the storms a couple of weekends ago, rolled up to Arrowrock dam. Built in 1915 way before Hover, Arrowrock was the tallest damn in the world. Built mostly for flood control and irrigation. Arrowrock tamed the then wild Boise river. Lending a stability to the Treasure Valley critical to the last centuries growth.
Here is a photo of one on the 20 original “Ensign†Valves. These valves were run entirely by water pressure, needing no electricity to function. 
Want to see for yourself? Just head up highway 21 and turn towards Spring Shores after the bridge. Keep going till you see the damn. Takes 45 minutes or so from the Crow inn.