TROUT TIPS -- Remember the floods that hit our trout streams two and three years ago? There were major, rock-turning floods on some streams, especially the Root River system. How did the bugs survive these events -- why weren't they all washed away?

Thomas F. Waters, a retired University of Minnesota professor, writes in his book "Wildstream" about a new entomological theory that might explain why bugs survive these events.

This theory is that mayfly and stonefly nymphs burrow into the stream bottom and into the side of banks where they live until it's time for them to hatch. They are able to survive on just moisture, not needing to be completely in water.

These nymphs have been found burrowed several feet into the bottom or sides of streams. Entomologists have also found nymphs burrowed in dried-up river beds, waiting for the water to return.

This phenomenon might explain why bugs survive the major flooding we've had on some of our streams.

I highly recommend the book "Wildstream" if you are interested in learning more about this wonder of nature and other interesting facts about free-flowing rivers.

Trout Tips is a weekly feature by Wayne Bartz, a Rochester angler and a field editor for Midwest Fly-fishing Magazine. His e-mail address is waybar535@aol.com.