Ice And Trash Racks in Forebay Nov 23, 2006
This is the last line of defense for the turbines!
Ok, maybe a bit dramatic. These racks prevent large chunks of ice (and other debris) from entering the penstock and falling down into the turbines where they can damage the blades.
Rankine had more problems with ice than the Toronto Power Company station, primarily because the water had to make a 90-degree turn before entering the forebay. The Toronto Power Company station was positioned advantageously directly on the Niagara River's edge (apparently due to better political connections at the time). While ice was still a problem at that station, it wasn't to the same degree as it was with Rankine.