The Kettle River contains some rocky, high gradient rapids, most notably the series of whitewater rapids as the river flows through Banning
Kettle River
State Park known as Hells Gate. This area must be avoided or portaged around as it is extremely dangerous. Rapids also occur south of Robinson Quarry Park near Sandstone at the old dam site, at river mile 18.5 (between Sandstone and Highway 48, known as the Friesland Rapids), and near the mouth of the river
Train bridge over Kettle River
in St. Croix State Park. The Friesland Rapids and the area in St. Croix State Park can usually be canoed during most water conditions, although during low water you may need to pull the canoe through some spots. Most of the rest of the river can be paddled easily by a novice canoeist.
http://www.dnr.state.mn.us/areas/fisheries/hinckley/rivers/kettle.html
The Kettle River contains some rocky, high gradient rapids, most notably the series of whitewater rapids as the river flows through Banning