Anything for lakes fed off the bow are going to be about 4-6 degrees. I fell in Barrier last week and it was unpleasant. A quick dip to cool off maybe but nothing out that way is going to be a swimming lake, except for a few shallow ones that you're going to have to hike to.
The Bow from Ghost to Cochrane is pretty sweet, some rough patches. Not whitewater but I wouldn't take it with a $20 walmart raft either. You can stop at Wildcat park in the middle of the river (near the gas plant) for a break and snacks and whatnot, and there's a few little eddy pools you can stop at if you don't want to ride the river but just want to float.
If you're just looking at lakes to float on I'd go to Kananaskis, Spray, or Barrier. At least two of which have boat launches and good parking.
|