Hi Steve, I have a Backroad Mapbook for Eastern Ontario and it lists some paddling routes.
For the Clyde River it says "grade I-II... a number of great eddies....some rapids longer than usual...11 km.... 3 hours....best in the spring and early summer when levels are at their highest". When I look at the online gauge, it shows that the current level is about 8.3 metres, and on averge the water level drops below this level around June 10th. So this water level might be low but OK, June 10 is not later than "early summer"
For Playfairville, it says "grade I-III rapids... short 6km stretch... 2 optional portages at II-III...depending on runoff levels, this route is only passable in early spring to about mid May". The Ferguson Falls gauge shows that the water level is about 3.2 metres, and a typical mid May levle is about 3.3 metres. The Mississippi at the outlet of Dalhousie Lake gauge is all over the place, showing a peak in March, quite low in April, and more in May, and staying up higher than April through the summer, so that might suggest some weird dam stuff going on there, but we are higher than the mid May levels, and are as high as any average level for any time of year, but not sure I trust this gauge as much.
Oh, and the good-ol carp River is about 5.0m but my lower cutoff for that is 5.1. I know that well enough to wait for higher spring water.
So, neither of the ones that I have suggested are clearly at spring peak levels, but both are potentially passable. I could go with either one I think. If water level are low and marginal, maybe the shorter of the 2 is better. We're not planning on an early start, we'll let it warm up a bit. I'll check back here, and/or try giving me a call 613-832-0811
Peter