Each school has an equipment list specific to the river and season. You can download the trip details for your specific school here.
In the meantime, we've put together a list of the 6 things that every professional river guide should have (you may want to consider obtaining some of them before your school):
1. Good footwear. To guide is to abuse your feet. Get something that works and break them in before you get to the river.
Buy it: Chaco Z-2's, Astral Water Shoes.
Wing it: Old running shoes with wool socks.
Skip it: Anything with velcro-closing straps; crocs.
Bonus: Awesome tan lines!
2. Good fleece. A river guide without a fleece is like a jedi without a tabard. It is hard to have too much (but we all try).
Buy it: Patagonia Micro-D Pullover, Mt. Hardwear Microchill Zip-T
Wing it: Tommy Hilfiger closeout from Ross; thrift store stuff.
Skip it: Cotton.
Bonus: You can wear it around town and know you are legit.
3. Good hat(s). Sun protection, rain protection, warmth, comfort, cover-up; confidence comes from having something on top.
Buy it: Patagonia Trucker Hat, Columbia Peruvian.
Wing it: The beanie your boyfriend knitted for your 1st anniversary.
Skip it: Your grandmother's big, floppy sunhat; anything orange.
Penalty: If you have one of those retainer clips.
4. Good tent.Your home on the river. Even the worst possible day is made worse if your tent leaks.
Buy it: Mountain Hardwear Shifter, REI Half-Dome.
Wing it: Your friend's backpacking tent.
Skip it: Anything from Wal-Mart; anything orange.
Penalty: If you can't pitch it by yourself.
5. Good meshbag.Wet stuff stinks; wet stuff in a mesh bags stinks less. Bundling everything in your towel is noble, but a disaster.
Buy it: NRS Purest, The Summit Rig-Bag.
Wing it: Mesh laundry bag mom gave you for college; abalone bag.
Skip it: Wheeled carry-on; grocery bag.
Bonus: It makes a bad-ass laundry bag at college (no offense mom).
6. Good paddling jacket. You might not use it every day, but just knowing that you have one will make you feel warmer; like a kitten.
Buy it: Kokatat Super Breeze, NRS Paddling Jacket.
Wing it: Rainshell.
Skip it: Dad's golf windbreaker; poncho.
Penalty: Bringing a kitten instead.