Creek Alignment Coming Into View at Tualatin River NWR
The following 20/20 Blog post was authored by Todd McKinney, Park Ranger at Tualatin River National Wildlife Refuge.
If you’ve recently made your way to Tualatin River National Wildlife Refuge - or heck, if you’ve even just driven by - you’ve likely seen a lot of activity out in the wetland. Understandably, “activity in the wetlands” probably conjures images of waterfowl flocks, wading herons, or a deer and fawn grazing along the edges. But right now, the Refuge is hosting critters of a different, slightly more metallic, sort. Crews are working full tilt on the Chicken Creek Restoration Project, setting the stage for healthier and more viable habitat.
Three major actions have occurred since the contractors began moving soil on August 19th:
The historic channel has been excavated between the lateral ditch road and North to just about the photo blind.
Crews have worked tirelessly to create large woody debris structures in throughout the wetland.
Bulldozer work has made great strides filling in the lateral water delivery ditch, which will open up the area into one large wetland.
Carving the Channel
From day one, the contractors have been diligently carving out the new channel that was once Chicken Creek. The digging began at the end of the creek closest to the Tualatin River. A portion of the relic creek still exists near the photo blind and this is where they began scraping the earth, pulling up giant scoops of soil and loading them into massive dump trucks. The soil was then carried to a “spoils” pile that is located by the wayside entrance. This soil will be used to fill the existing, human-made Chicken Creek ditch.
Mimicking Nature with Woody Debris
In this “pre-water” phase of the project, one interesting thing to watch is the installation of the large woody debris. Seeing this activity has been fairly easy and engaging, partly because it’s happening close to the walking paths. Visitors with fortunate timing have been able to witness how the logs are driven into the earth and arranged in very particular ways. All of which is meant to mimic how tree debris would naturally enter and settle into a more established creek and wetland system.
The pattern usually involves placing a large tree flat along the ground to serve as a starting point for the structure. Other logs are driven into the ground, end-first, criss-crossing the first log. One passing visitor noted that this seemed reminiscent of beachfront barriers used during World War II.
While wildlife watching usually passes as the main form of entertainment at the Refuge, seeing these logs installed has been a unique treat. A large excavator, first, picks up the tree while a chainsaw operator trims one end like a pencil tip. Next, the excavator hoists the log into a vertical position, lines it up where they want it, then pushes it into the earth for stabilization. Once the log is stable, the bucket on the excavator is used as a hammer to pound it deep into the soil. This blunt force takes its toll on the log ends, which is why you’ll see a lot of shredded wood on the exposed ends.
If you’re wondering what the wildlife makes of this activity, you may or may not be surprised to learn that some of the more curious species are taking a front row seat. We’ve already heard from some of our regular photographers that several birds of prey have been using these structures for perches. Though it’s a early in the process, this constructed habitat is already working.
Filling the Void with What’s Already There
Next to where they’re digging the channel and placing debris, you may have seen a large bulldozer working up and down the South side of the lateral ditch road. What’s happening here is filling of that ditch, which had historically been the way water was delivered throughout the Refuges six wetland cells. Chicken Creek will be allowed to once again do that work naturally, so the ditch is no longer needed.
Conveniently, the material for filling the ditch was already in place. The bulldozer is essentially pushing in the sides of levee to fill the middle. When completely filled in, what were once two separate wetland cells will be seamlessly connected to form one very large wetland, with water flowing freely between the two areas.
Opportunities to Get Involved are Right Around the Corner
Work, thus far, has moved along quickly and smoothly. We should start to see equipment leaving the Refuge by the end of September. If you’re looking to get involved with the restoration project, please stay tuned. We will be organizing a couple of large scale plantings this Winter. Dates will be posted here at Refuge 20/20 and on the Portland-Vancouver National Wildlife Refuges Facebook page as soon as the details are sorted out.