The Bruno Mt. section of the North Santiam is a great run, as long as the skill level of your group matches up with the flow. I would say the minimum enjoyable flow is around 1,400 cfs. At this level, most of the run consists of fairly technical class III. Between 1,800 and 2,500 cfs, this is a great III+ run, with good sized waves and LOTS of play. As the river rises over 3,000 cfs, it becomes a non- stop big water run with some big holes and an abundance of catch on the fly surf waves. It's still not very difficult at this level, but eddies are very scarce, so a swim could last a very long time. This section never really washes out. It just keeps getting bigger and faster.
In the Summer, it can be run by desperate locals down to 400 cfs or so. At that flow it is more a training run and shorter sections should be bitten off so it doesn't take all day. It's more II-III at that flow with lots of rocks, but also some clean lines and loads of small features to practice in.
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Soggy Sneakers.