All of us fishing in riffles or using nymphs must have snagged the gravel on the bottom of a beat at sometime, then waded to release the snag disturbing all the trout for 20 yds upstream of where we've been fishing.
Domenick Swentosky (US Fly Fishing guide) posted an easy way to release snags on his Troutbitten blog. The simplicity of the way he shows to release a snag had me thinking about the number of times I'd battled this situation only to make it worse and have to use a arm in the water or net to release the snagged up hook.
If you haven't come across the blog before then its well worth an explore. His standard mono-rig set-up is now my go to leader for late season trout and grayling nymphing; its way cheaper to construct than puchasing specialist Euro Nymphing lines or specialist long nymphing leaders. The Maxima construction can also cast a dry fly a few rod lengths if the trout change from taking nymphs to dries (but of course its not as efficient as using a standard fly line for dry flies).