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septimus prime
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  Quote septimus prime Replybullet Topic: River Physics 101
    Posted: 06 Jun 2014 at 4:57pm
Off to your favorite river destination already, huh? Told the boss you are working from home this afternoon...hmmm?

Well pop quiz. Due on my desk by...whenever you feel like it(WA standards based grading in a nutshell)

You arrive at your favorite creek to discover a large tree has fallen perpendicular to the thalweg in the middle of your happy place drop. The DBH of the tree is a little more than twice the length of your Stihl chainsaw bar.

Write a procedure for cutting it out (my wife is a fisheries biologists so I feel justified. kinda like planting trees to offset the miles you drive) and be sure to include which side of the stream (up or down) you would make your first cut.

Edited by septimus prime - 06 Jun 2014 at 4:58pm
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Travisimo
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  Quote Travisimo Replybullet Posted: 06 Jun 2014 at 5:13pm
drill 1" hole, about the depth of a stick of dynamite.

Insert dynamite into hole, light and run away. Fast.

Ooooorrrr... This is tough and really depends on how heavy the tree is and where it's going to fall (can it just sink until the wood boyancy takes over, or is it going to bounce... like usual)

Kind of like it's tough to tell a novice how to fall a difficult tree, it's really hard to make a "safe" procedure that works consistently that doesn't include the person taking a dunk with the saw and tree together.

I've always cut a notch on the upstream side first just like falling a tree. Then I cut from the downstream side and keep jumping off when I think I'm going swimming, pulling with a rope from downstream has always gotten the last part to snap... but it's a delicate operation and pretty much different every time. Sometimes that rope on the downstream side is good because we can get the log out of the main flow then with it...

Edited.... I failed the test first! Swapped sides!

Edited by Travisimo - 06 Jun 2014 at 9:55pm
H2O please
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Travisimo
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  Quote Travisimo Replybullet Posted: 06 Jun 2014 at 9:59pm
Bump... In case anyone read my first post, I swapped sides... Notch up, cut down so the blade doesn't bind. The notch makes the tree bark separate and make two pieces. Once I purposely did not notch so the tree would bend enough to be free and we pulled it out, have also pulled them without cutting... Waiting for very low water is usually safest though!

Edit edit... Trees we care about tend to be really scary since the water is moving fast, or we wouldn't care. Be safe.

Edited by Travisimo - 06 Jun 2014 at 10:04pm
H2O please
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mokelumnekid
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  Quote mokelumnekid Replybullet Posted: 07 Jun 2014 at 7:42am
My understanding is that down-trees and woody debris help create the diversity in environment that salmon and other fish need. But having said that I understand if something is manifestly dangerous it's position can be "adjusted" to benefit both   
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Travisimo
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  Quote Travisimo Replybullet Posted: 08 Jun 2014 at 12:44pm
That does not apply to any tree I've ever heard of a kayaker removing.

I remember a fisherman swearing to me that there are steelhead at the Putin for the upper upper Cispus. When I told him of the 30 foot falls, he told me fish jump high...

Generalizations are always false.
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mokelumnekid
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  Quote mokelumnekid Replybullet Posted: 08 Jun 2014 at 5:17pm
Fair enough not so much generalizing but thinking very specifically about all the research done on the role of woody debris of all types on conditioning the fluvial environment for migrating fish. A lot of which has been done in my workplace so I'm reasonably familiar with it. It had enough street cred to motivate changes in logging practice and river management. Point being I wasn't blowing smoke or seeking to advance some vague under-powered assertion. But at the same time didn't think that throwing around references to said studies was especially interesting to anyone.
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jon!
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  Quote jon! Replybullet Posted: 11 Jun 2014 at 8:11am
I like the dynamite idea. It requires less thinking and more running!
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knarfks
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  Quote knarfks Replybullet Posted: 14 Dec 2014 at 8:37am
https://www.youtube.com/watch?feature=player_embedded&v=pnbJEg9r1o8

I know it doesn't have to do with log removal, but a cool fluid dynamics video that applies to the river.
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Slackkinhard
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  Quote Slackkinhard Replybullet Posted: 14 Dec 2014 at 5:59pm
she is much better than Bill Nye

Edited by Slackkinhard - 14 Dec 2014 at 6:00pm
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portagebro
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  Quote portagebro Replybullet Posted: 14 Dec 2014 at 8:05pm
Our sport first became popular after decades of riparian logging (including the splash dam approach to getting the logs out to the mills) removed most of the potential for logs in our rivers. Now after a few decades of buffer strip requirements, we can expect large wood hazards to begin recovering to natural conditions. Essential for salmon recovery, not so good for kayaking.
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