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Interesting (novel?) technique for slowing water in channels during flood events  RSS feed

 
Michael Cox
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Location: Kent, UK - Zone 8
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I saw this mentioned very briefly in a BBC program yesterday, with very little detail. I managed to take a few screen shots but couldn't get the clip.

The big advantage of this method seems to be that it acts along the whole length of the river channel, rather than constricting at a single span as a check dam would. One criticism of check dams and gabions is that if conditions are not right the water flow can divert around them and form new channels. Timber is often a free and easy resource on large scale land restoration projects.

floodmanagement.png
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Logs are strapped to each other in a criss-cross pattern along the length of the river bed.
floodmanagement2.jpg
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Stone and other sediment are trapped in the shelter of the logs and deposit rather than being carried down stream. The sediment builds in depth over time - perhaps until the logs are buried?
 
Miles Flansburg
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Location: Zones 2-4 Wyoming and 4-5 Colorado
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As long as the logs are close enough to the stream bed that water cannot go under them.
Here in Colorado there was a huge fire about ten years ago. Afterwards they dropped 100's of burned trees in the stream beds to stop erosion. The water went under the trees and dug the streambed down another ten feet, in some places, to bedrock. Leaving the trees as bridges hanging above from bank to bank.

 
Rose Pinder
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Location: Otago, New Zealand
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Nice photos, thanks.
 
Dean Howard
Posts: 126
Location: NE ARIZONA, Zone 5B, 7K feet, 24" rain
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Miles Flansburg wrote:As long as the logs are close enough to the stream bed that water cannot go under them.
Here in Colorado there was a huge fire about ten years ago. Afterwards they dropped 100's of burned trees in the stream beds to stop erosion. The water went under the trees and dug the streambed down another ten feet, in some places, to bedrock. Leaving the trees as bridges hanging above from bank to bank.


I'm wondering if the huge loss of soil would have been worse without the logs to slow the water down. In other words, huge fire, nothing to hold the run-off, and without the logs, the damage may have naturally occurred in just as severe a fashion, if not worse... ? I don't know...
 
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