The Nature Conservancy in August used a helicopter to drop 26 logs into its Port Susan Bay Preserve in the Stillaguamish River delta. The environmental group hopes the logs will improve tidal channels that juvenile salmon use to migrate out to sea.
The logs are cabled together in clumps and secured to the ground so they don’t wash away.
Danelle Heatwole, an ecologist with The Nature Conservancy, led the log drop project and is monitoring how well it’s working.
What do the log jams look like?
We have three different sizes of log complexes. In each of the two channels there’s a two-log complex, a four-log complex, and a seven-log complex. So the complexes vary in height and size. The ones with seven logs are a lot more stacked.
Why the different sizes?
We wanted to see if we got more change in the shape of the channel if there were more logs in the complex, if the extra investment was worth it.
Why do you want to change the shape of the tidal channels?
There are certain features of channels that we think are important for juvenile salmon. For example, if there is a pool in the channel, the water might move more slowly there and the fish can rest. The pool could also have a lower temperature than the rest of the channel, and be a less stressful place for the fish to hang out.
The concept is that these log jams would allow scouring to happen below the wood complexes. Are you finding that these pools are forming?
We have seen some shifting and scouring in the sediments. It looks like there may be some pools forming, which is good, but the pools may get filled or moved over time. We need more time to see what will end up happening.
How will you know if the project is successful?
Keeping in mind that the goal was to evaluate the benefits of putting logs into these tidal channels for salmon, any information that we gain toward answering that question will be useful.
What have you been doing to manage the site?
We’ve been monitoring the logs and taking photos to keep track of what’s happening through the winter.
What’s next?
The first accounting of how many fish are using the log jams is scheduled for March or April. That is a time when juvenile salmon would be using the area. From then, the plan is to monitor the site each fall and spring for two years.
Reporter Lukas Velush: 425-339-3449 or lvelush@heraldnet.com.
About the preserve
The Port Susan Bay Preserve is 4,122 acres of tidal channels and mudflats at the mouth of the Stillaguamish River. The Nature Conservancy bought and manages the estuarine habitat for salmon and for migrating birds.
VISITATION
By appointment only. Call preserve steward Kat Morgan at 360-419-7059.
FOR MORE INFORMATION
Go to www.nature.org and enter “Port Susan” in the search field.
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