MONROE — The floods that wreaked havoc across much of Snohomish County this fall were not felt at one spot on the Skykomish River, a location recently thought so vulnerable the County Council approved an emergency ordinance urging it be fixed.
Prior to this fall, a major flood easily could have sent the entire Skykomish River down an old river channel at the southeast edge of Monroe, local flood experts said Monday.
If that were to happen, the swollen river would first wipe out a county road, then wash out Highway 203 and then possibly destroy any number of homes and farm buildings, flood experts say.
Also in its path would be Haskell Slough, a side channel to the Skykomish that has become extremely productive habitat for juvenile salmon since it was recently restored.
"Estimates are that it would cost $40 (million) to $65 million to fix the damage," said John Sayre, executive director of Northwest Chinook Recovery, a regional environmental group that has led efforts to stabilize the Skykomish’s bank.
Although both of this fall’s floods were big enough to possibly send the river down a new destructive course, it didn’t happen.
While floodwaters did spill over on to cattle rancher Dale Reiner’s property, they first were slowed by a just-completed zigzag fence constructed of giant fir trees chained to wooden pilings pounded 20 feet into the ground.
The 1,000-foot contraption is what farmers, environmentalists and about 25 government officials Monday called an "innovative" way to protect downstream buildings and roads while also protecting the habitat of endangered salmon.
"This is beyond win-win," Rep. Hans Dunshee, D-Snohomish, said minutes before touring the site. "This works for farmers and for fish."
The state Legislature funded the $798,000 fence built in October and November. Next spring hundreds of cottonwood trees will be planted for additional stabilization.
"We hadn’t even finished when the first flood occurred, and it was already working," said Jack Sell, of the civil engineer firm Layton Sell Coastal, which helped design the structure. "It has already stopped a flood."
Sell said the wood structure is designed to catch logs and stumps that float down the river in a flood. The large objects — there already are several stumps wedged behind the fence from the recent floods — will cause the river to slow, which will allow the soil, sand and gravel that it’s carrying to fall out of the water.
Over time, such deposits will allow the riverbank to build up naturally. There are already small drifts of sand built up, some as tall as two feet.
The eventual goal is to use the site as an example of how flood damage can be stopped while protecting endangered species habitat, said Sayre, whose Northwest Chinook Recovery facilitated building the flood protection fence.
Sayre said the hope is to open up the entire Haskell Slough, only the bottom is open now. If water is allowed to flow through from top to bottom, it would become more productive salmon habitat.
Without the new fence, the slough could be destroyed because the river’s new path largely would follow the route cut by Haskell Slough, he said. The then-abandoned river channel eventually could become viable salmon habitat, but that would take time.
Reiner said he got involved in the project after losing 80 to 100 acres of productive land to floods in the late 1990s. During each flood, the shifting river would dump massive amounts of sand and gravel on his farmland as it carved away at the weakened riverbank.
"My property is worthless," he said, saying that the project is to make sure the same thing doesn’t happen to farmers downstream from him. "This is no longer usable farm land. It will take literally decades for this to become usable farmland again."
Reporter Lukas Velush: 425-339-3449 or lvelush@heraldnet.com.
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