Must have: synthetic base layer, top & bottom, both light and heavy ones; throw bag and knife; neoprene booties with a good sole for scouting on rocky slopes; buddy with throw bag to help pull you out of the drink. Add to this:
Cheaper setup: drytop with heavy neoprene shorts or shorty farmer john wetsuit
Better setup: drysuit
Wise to have if you boat much in CO: pogies, Doc's ProPlugs (to prevent exotosis)
If you start to creek a lot, consider a facemask or mouthguard as well. Though most of us eschew both, you ought to consider the pros and cons before going without on a shallow run.
The better you get, the less you swim, the more you can go without as much warm gear on easier runs. I still wear a drysuit on any creek because if you have to do a rescue or recover a pinned boat, you never know how long you may have to be wading in really cold water.
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