We are overjoyed to have hosted our first in-person meeting since before the pandemic, and first field tour since 2019! Last week the Forest Service and members of the Pinchot Partners forest collaborative group took a field trip to view Cispus River-Yellowjacket Creek Restoration project where the Forest Service is currently working in partnership with The Cowlitz Indian Tribe to improve salmon and steelhead habitat for threatened Coho and Chinook salmon and steelhead trout.
This area has been targeted for restoration due to its high potential for enhancing spawning and rearing habitat. In its existing condition, the lack of instream large wood limits the quality and quantity of instream habitat for salmon. The project area falls short of its natural fish production potential due to natural and human caused disturbance.
Major natural events have affected the Cispus River watershed, like ash from the 1980 eruption of Mount St. Helen’s, widespread turn-of-the-century fire, and multiple flood events. Past land management practices focused on timber production harvested much of the available standing large trees, as well as a lot of the large organic material the river naturally transports.
Today, with an improved understanding of river dynamic, we now know the importance and key role mature forests and woody debris play in developing healthy fish habitat.
During the field trip on July 21, the Pinchot Partners along with Forest Service staff viewed some of the “engineered log jams” along the Cispus River that are being built to mimic channel-forming processes that happen when a large, 500-year-old tree falls. The substantial and stable “engineered ‘log jams” are embedded about 20 feet into the river and rise another 10 feet above the stream bed as sequentially layers of large wood and slash. Much like a naturally formed log complex, the structure is backfilled with river substrate and planted over with native trees thanks to Cascade Forest Conservancy volunteers, to help hold them in place.
The construction sequence is meant to mimic the decades of natural development required for debris and sediment to collect around a giant fallen log and result in desirable forested islands. Some short-term response of “engineered ‘log jams” will shift the river channel slightly, re-establish side channels, and create pools of deeper cooler water where fish can survive and find refuge during periods of warming or floods.
These “engineered ‘log jams’” are built to last. Though a few components may be moved over time, tested construction techniques and hydraulic modeling support the durability of these structures. The current phase of development has 18 jams under construction within a half-mile section of the Cispus River/Yellowjacket confluence. Managers expect to observe the jams over time to assess how they affect the river and lend to salmon recovery effort.
Many thanks to everyone who brought this together, and sincere appreciation from everyone in being able to enjoy the National Forest together! Special thanks to Elizabeth Robinson (USFS), Nikia Hernandez (USFS), Eli Asher (Cowlitz Indian Tribe), and Amy Boyd (Cowlitz Indian Tribe) for their efforts in planning the tour and sharing their knowledge.