Valleyfield is pretty much as described in the www. Slalom kayakers from Ottawa travel there regularly to train while we wait for the NCC etc to finish the work on the pumphouse, as as a change of pace.
It isn’t private, however, they do appreciate a donation to maintain the gates and facility generally. There is some good play and it is very reliable water – not huge, but worthwhile. Last year they had a ramp built a la Gull, not sure if it’s still there. The water is also very clear which makes a nice change from the pumphouse.