Salman,

I don't think I have any photos specifically of redd scour. I could take a photo of a gravel bar that is high and dry, but is where the river channel formerly was prior to the last high water event. Any salmon spawning redds in that former stream channel were scoured and then refilled to create the gravel bar that is there presently.

Another example of redd scour would be in lower Diobsud Creek, tributary to the Skagit River right near where the Hwy 20 bridge passes over it. The stream channel looks almost exactly the same before and after a high water event. However, I knew that all the pink salmon redds that had been constructed there were scoured away and long gone. We had installed scour chains, buried 24 to 30" deep in the creek bed. I think we recovered one or two, but the rest were completely gone, meaning that the high water had scoured the stream bed 2 1/2 to 3 feet deep and then refilled the channel with fresh gravel from upstream, carrying it down during the high energy high flow event.

I list the above as examples of what redd scour might look like. There are others ways redd scour might present itself as well.

Logging doesn't directly cause redd scour, at least in the terms of how I usually think of it. What logging does is change the runoff patterns of rain and snow, with rain events generally running off into stream more quickly due to the bare ground and lack of forest canopy. So what happens is that streams that have upstream logging will rise faster and higher (peak flow) than streams without logging. Higher flows mean higher energy, and higher energy causes scour, and deeper scour that destroy redds by mobilizing both the gravel and eggs. And that kills the eggs. And we haven't even gotten to the part where logging results in rain and snow runoff causing increased erosion, dumping huge quantities of fine silt and sediment into the water column, so even if redds are not scoured, they are smothered, reducing the critical oxygen exchange necessary for the eggs to live and develop to hatching and emergence.

What can be done about it? A lot of things, but they aren't real popular with the timber industry because it reduces profitability. The beneficial measures include buffer zones, wider buffer zones, no entry buffer zones, limited entry and harvest buffer zones, smaller logging units, longer rotations between harvests, proper abandonment of old or unused logging spur roads, fewer roads to begin with, aerial yarding of logs, paving logging road mainlines, and other actions that I can't think of right now. Then again, not logging at all is the best alternative for stream health, but then we would not have the wood fiber that is critical to our way of life. Many of the mitigating measures I listed have been adopted, going back as far as the Timber, Fish, & Wildlife Agreement legislation of 1989 and the Fish & Forests plan of, oh about 2005 I think. I don't remember exactly when that was completed. The upshot is that WA has the most restrictive forest management and timber harvest rules in the U.S. And stream health has improved in some cases, maybe a lot of cases. But it is usually a slow process, measured more in decades than years. Hope this info helps answer your question.