Fly Lines

There was a time when I thought of the natural world as stable. I was not so keenly aware of the power of catastrophic events. In an instant Mount St. Helens changes all that. After she blew her top, I could not look at the Cascades in the same way. I read about even bigger events, like Mount Mazama, and somehow the ground I was standing on didn't seem quite so stable.

My view of rivers was a lot like my broader view of nature. I knew rivers were in a constant state of flux; continuously changing. They have to be changing or how else could they dig canyons or build river deltas? But I didn't think of this change as being catastrophic. I saw it as being slow, inexorable; like watching the hands of a clock move.

I did not fully appreciate how sudden and dramatic events could be until three summers ago when a mud-and-rock-slide added a new rapid to the Deschutes.

Since that mud slide there have been two similar events on the Metolius. Neither made a rapid, but with slightly different circumstances they could have. Knowing what these mud and rock slides look like and how they operate, I can now see clear evidence that they have run out of many side canyons on rivers throughout the Northwest.

Lots of the rapids fisherman and rafters think of as stable and constant where created by this type of event. The rivers have been making these dramatic changes, adding and deleting rapids in an instant, since the beginning of time.

Another catastrophic event which has been very interesting to observe first hand is the flood of two winters ago. Standing next to some of the piles of gravel that were moved, I'm awed by the raw power that was present. Construction companies spend years moving that much rock on a highway project.

When these catastrophic events are over they tend to leave raw scars on the land. The mud slides end in piles of boulders, rocks, dirt and broken trees. The floods uproots the alders and rip away the top soil leaving the land scarred and barren.

It would be easy to curse the disaster and say, "It has ruined the place I love."

I think that is too narrow a view. After all, floods, mud slides, volcanoes and other natural disasters have been shaping this land for a long time. They are a part of what the place is. I prefer to look at the way the land and the river respond to the change - to see how these amazing events become part of the natural system.

After the cleansing of the flood, the spawning gravel was flushed clean. For the first time in several seasons we saw the Chinook salmon back in the Warm Springs to the Trout Creek section of the Deschutes. During the low-water years they had been driven downriver to spawn in a completely different area from their historical grounds.

Over last winter we had more minor flooding - it filled in a lot of the damage of the big flood two seasons ago. In many places where the land had been scarred the currents this season were less severe and the soil filled in. The roots, trunks and limbs of washed out trees played a major role in catching sand and soils and re-depositing them. The land was finding a way to heal itself.

The effects on the river are so broad-reaching, even the insect populations are change by these natural events. I noticed last fall that there weren't as many October Caddis as there had been. Research on a stream near Ashland shows that these lumbering insects, which have limited mobility, are more easily affected by floods than other creatures. When the gravel moves they can't escape and are either crushed or destroyed.

October Caddis larva graze heavily on river algae. When they are not present there is more food for smaller insects. The smaller insects become food for the young salmon, steelhead and trout. Larger October Caddis Larvae are too big for the little fish to eat.

After a flood there is an increase in small trout and salmon directly related to these changes in the food web. If you're observant it's amazing the things you can learn about the wonderful intricate ways nature finds to replenish itself after an apparent disaster