E.g.:
http://www.history.rochester.edu/canal/bib/whitford/1921/CHA...

The one alternating current station is situated at Crescent dam and furnishes power for the five locks and the two guard-gates on the land line between the Hudson and Mohawk rivers. This station contains three 75-kv.-a., 2,300-volt, 3-phase, 40-cycle, vertical generators directly connected to Francis inward-flow turbines.

E.g. 2:
http://www.corestore.org/cullsurge.htm
A differential surge shaft typically has the small riser shaft concentric with the large one. The reasons an arrangement of seperate shafts was used here were twofold: Since a gate is fitted to allow dewatering of the high-pressure system (and as a guard gate), use of a seperate shaft upstream of the gate allows the relief of water hammer when the gate is closed.

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Note added at 18 mins (2008-04-26 16:45:09 GMT)
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Reference: Termium