Battalion Chief David Cooper says people seem to think the Boise river is much safer than it really is.
"It's not a carnival ride. Just because it goes through the center of town and literally tens of thousands of people are on it in any given weekend, it doesn't mean it's safe," said Cooper.
Boise fire rescues about 30 people every summer from the river.
"I'd say our two biggest problems are too much drinking and too little life jackets," said Cooper.
He says the safest place in the river for floating is in the center, away from trees and debris along the banks.
"We've had very very good swimmers fall out of their rafts and not be ready for that cold water and not be able to swim in it. In some spots the river is shallow enough that people get flipped out of their rafts, they hit their heads and they can't swim because of that too," said Cooper.