PacifiCorp Energy prepares for seismic retrofit of Yale Lake’s Saddle Dam

Project, expected to run through June 2024, is not expected to harm wildlife after remediation

By Lauren Ellenbecker, Columbian staff writer

Published: January 26, 2023, 6:00am

2 Photos

Saddle Dam on Yale Lake, one of three large reservoirs on the North Fork of the Lewis River, will be retrofitted due to seismic concerns, leading to park closures and a temporary displacement of nearby elk habitats. (Photo contributed by PacifiCorp) Photo Gallery

An unassuming grassy slope at the southern edge of Yale Lake on the North Fork Lewis River plays a crucial role in preventing the 3,780-acre reservoir from pouring into the land below.

Saddle Dam, an earthen wall stretching 1,600 feet long and 40 feet tall, isn’t the main barrier that contains Yale Lake. That would be Yale Dam, which sits 1,000 feet south of Saddle Dam and features a classic concrete spillway and a PacifiCorp Energy hydroelectric station that can generate enough megawatts to power 134,000 homes, according to spokesperson Tom Gauntt.

The embankment may be meager compared with its larger counterpart, but a large-scale earthquake could loosen Saddle Dam’s soil foundation and result in an uncontrolled flood from the reservoir. The seismic threat, although not immediate nor certain, could reach magnitude 9 and happen within the next 50 years, according to project documents.

As a precaution, PacifiCorp intends to build a filter buttress on the downstream side of Saddle Dam and, farther along the stream, install a shallow drainage ditch into a central swale, a sunken channel, to protect the embankment if earthquake-induced cracking occurs, Cowlitz County environmental planner Peyton Murphy said during a public hearing last week. On the upstream face of the dam, there will be loose stone structures, or riprap, to form a barrier intended to protect from erosion caused by wave run-up.

There was no public input regarding the project, according to officials.

Large and small mammals, bull trout and Kokanee salmon, as well as more than 100 bird species, occupy the nearby valleys and meadows, according to a wetland and critical areas report prepared for the project. The area is teeming with natural life, some of which will be disrupted by PacifiCorp’s seismic remediation.

Notably, meadows west of Saddle Dam that are frequented by hundreds of Roosevelt elk year-round to forage will be used as a staging area for construction. Gauntt said there will be restoration projects to maintain these habitats following the dam’s retrofit.

Grounds for construction downstream of the dam will require the removal of roughly 140 trees, including Douglas fir, bigleaf maple and red alder. Chestnut trees are also scattered through the western forests. Gauntt said that for every tree removed, PacifiCorp will plant three to restore disrupted wildlife habitats, which complies with the Lewis River Wildlife Habitat Management Plan.

Fifteen acres of upland herbaceous habitats, which mostly consist of non-native grass and forbs, will be disturbed during the project; PacifiCorp will cover that area with a seed mix after construction is completed. Downstream, 6 acres of vegetation will also be disrupted.

Small bodies of water and four streams sit within the project area, but construction limits will be established to avoid work within 200 feet of the wetlands, streams and ponds.

Cowlitz County, the State Environmental Policy Act lead agency, deemed that the project will not have severe impacts on the environment.

Pending all the necessary state and federal permits, including a license amendment from the Federal Energy Regulatory Commission, PacifiCorp will open the bidding process. It anticipates kicking off construction in the fall. The utility will also lower Yale Lake to 465 feet to allow for construction access, about 25 feet below “full pool” levels.

Saddle Dam Park — often visited by picnickers, water sport enthusiasts and horseback riders — will be closed during the project, which is expected to continue through June 2024, according to project documents. The boat launch at Saddle Dam Park at the southern end of the dam will also be closed. An equestrian trail that leads northwest of the lake will remain partially open.

To accommodate recreational users during these closures, parking lots and restrooms will be relocated. PacifiCorp will move its boat launch north to Yale Park, and supplementary parking will be added to Cresap Bay and Speelyai Bay.

PacifiCorp will release exact dates for park closures closer to its expected time frame in September.

This story was made possible by Community Funded Journalism, a project from The Columbian and the Local Media Foundation. Top donors include the Ed and Dollie Lynch Fund, Patricia, David and Jacob Nierenberg, Connie and Lee Kearney, Steve and Jan Oliva, The Cowlitz Tribal Foundation and the Mason E. Nolan Charitable Fund. The Columbian controls all content. For more information, visit columbian.com/cfj.

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