Deschutes Estuary Dam Removal Alternative Explored in New Book

 

Photo: The four basins of the impounded Deschutes River as seen on November 2. Percival Cove is in the foreground. The south basin is directly east of the cove, with Capitol Lake in the middle, and Budd Inlet in the distance.

By Janine Gates Little Hollywood

It’s running over old ground, but better late than never, say advocates with an alternative to the removal of the 5th Avenue dam on the Deschutes River in downtown Olympia.

Four authors, Dave Milne, Jack Havens, Bob Wubbena, and Bob Holman have written a new book, “A New Percival Creek Estuary and Capitol Lake: A Win-Win Alternative for Olympia (and Washington State).”

While it is now almost undisputed that a tidally influenced estuary would improve the ecological functions of the lower Deschutes watershed and restore year-round fish passage, how to best do that remains the question in the minds of these authors.

The authors advocate for the preservation of Capitol Lake and parallel it with a new constructed Percival Creek estuary.

Jack Havens and Bob Holman spoke at a public hearing held by the Washington State Department of Ecology on October 28 for new design elements of the Deschutes Estuary Restoration Project. The deadline for public comment to Ecology is November 9.

According to Ecology, the design process is expected to be completed by mid-2027, with construction expected to begin in 2028. It is anticipated that the entire project will take six to seven years to complete. Funding for the project’s construction has not been secured and is expected to exceed $400 million.

In 1951, the 260-acre Capitol Lake was created as part of the Capitol Campus by damming the Deschutes River at Budd Inlet. The area has been divided into four basins: north, middle, south, and Percival Cove. The dam, which prevents the natural mixing of fresh and saltwater that naturally occurs in an estuary, is located in the area of the north basin and Tumwater Falls is in the area of the south basin. Deschutes Parkway, a major transportation route to and from Tumwater and in and out of downtown Olympia, travels around Percival Cove and the middle basin.

Havens, a veterinarian and community volunteer, and Holman, a chemical engineer who retired from the LOTT Clean Water Alliance regional wastewater treatment plant, said at the hearing that they think the project will exceed one billion dollars. None of the authors can attribute a source for this dollar figure.

All four are long-time residents of the area and have participated with varied aspects of the conversation, including state agency, port, citizen, and technical advisory boards.

Photo: Dave Milne, co-author of “A New Percival Creek Estuary and Capitol Lake: A Win-Win Alternative for Olympia (and Washington State),” during an interview on November 2.

Dave Milne, a retired environmental sciences faculty member at The Evergreen State College, chatted about his book in an interview with Little Hollywood on Monday. The book, which is not yet available in bookstores, is available from Milne upon request.

Milne says he isn’t trying to stir up controversy this late in the game. 

“What we are presenting is an alternative to fall back on once it’s realized that the funding objectives are unattainable.” Recalling how the Capitol Lake versus estuary debate raged in the early 2000s, Milne said restoring the estuary would be a “worst-case scenario” for our area’s marine and freshwater future.

Speaking of Washington State agency staff, dam removal advocates, and others who have worked for years to get near-universal tribal, federal, state, and local collaboration on the dam removal project, Milne said he thinks “they are working in good faith, but the reality will catch up. Removing the dam is wishful thinking. They insist the lake is not protecting downtown, but it is,” said Milne.

Photo: The Washington State Capitol Building and Capitol Lake earlier this week.

Milne said that at this point, Capitol Lake is performing a valuable service removing nitrogen from the water. The lake has not been dredged since 1986, and has become a de-facto wetland, with habitat hosting wildlife, migratory and resident birds and waterfowl.

Sediment accumulation has made the maximum depth in the north basin about 20 feet, and the middle basin is about three feet.

“There is water clarity. In fact, Capitol Lake has been swimmable since the 1990s,” said Milne. Swimming was officially discontinued at the lake in the mid-1980s.

In its entirety, Capitol Lake basins host 72 stormwater outfalls, 30 of which officially discharge city of Olympia street and stormwater runoff into the lake.

Photo: Percival Cove and the Deschutes Parkway

The Percival Creek Plan

Percival Creek originates in Trosper Lake in Tumwater, a once rural area now seeing urban and industrial pressures. Before the dam was constructed, the creek once flowed into the Deschutes River and directly to Budd Inlet. In 1922, a drainage channel, later called the Black Lake Ditch, was constructed at Black Lake in southwest Olympia. The channel joins the creek and contributes significant flow into the Deschutes basin.

Today, Percival Creek enters Capitol Lake through a weir-like screen just east of the Deschutes Parkway bridge near Marathon Park. A BNSF railroad line parallels the creek in the lower reaches.

Percival Cove, immediately to the west, is an isolated water basin, once used for decades by the Washington State Fish and Wildlife as part of a Chinook salmon hatchery program. The cove became a major source of phosphorous, derived from fish food and waste, into the lake. These net pens were phased out and removed in 2007. According to the City of Olympia, there is still some potential for this area to be a properly functioning fish habitat that warrants protection and restoration activity.

Restoring the Percival Creek estuary is not a newly found interest. A salmon habitat protection and restoration document produced by the Thurston Conservation District in the early 2000s said that Deschutes coho are found in Percival Creek and the Black Lake Ditch. Thurston County, the City of Olympia, and Tumwater own most of this area.

In their book, the authors admit their alternative has its own set of challenges, requiring the possible purchase of residences west of the parkway or moving a section of the railroad track. Still, Milne said this solution would be more economically and ecologically attractive to removal of the dam.

The management of Capitol Lake has raged for decades, with multiple plans and studies to address flooding, water quality, shoreline habitat, fisheries, sedimentation, the infestation of the invasive New Zealand mud snail, and other considerations. 

In the 2000s, a team management effort by tribal, state, and local government entities called the Capitol Lake Adaptive Management Plan finally fell apart in 2010. [See CLAMP Gets Clamped Down, Little Hollywood, May 6, 2010, at https://janineslittlehollywood.blogspot.com/2010/05/clamp-gets-clamped-down.html]