Why the open water in the Canal

The water current in the the canal is fairly strong, much like a small river, thus keeping the water open. It will freeze up, or get plugged up with ice, but usually doesn't last long.
In the Springtime, you will be able to see chunks of ice drifting back and forth through the canal as the current reverses several times a day due to a phenomenon called a "seiche" (SAYSH, a French word that means "to sway back and forth"). This happens when water piles up on one side of the lake because of wind or high barometric pressure and then shifts back to the other side. Small seiches occur all the time.

Spring is here!  Almost!