Flood control advocates argue flow-through dam doesn't mean salmon devastation

May 15-Local flood advocates say evidence shows local communities don't need to choose between flood prevention and protecting vulnerable fish populations.

Chehalis Basin Board member J. Vander Stoep, Chehalis Basin Flood Authority Chair Edna Fund and longtime Flood Authority member Ron Averill visited the Centralia City Council Tuesday evening with new information about the impact that a proposed flow-through dam could have on the basin.

The information, which made its first appearance at a Chehalis Basin Flood Control Zone District meeting more than a month ago, shows a virtually imperceptible impact to basinwide salmon populations after the construction of the flood structure.

"No one wants their communities flooded. On the other hand, we all have an attachment to the fishery sources," Vander Stoep said during the meeting. "This says that we don't have to pick one or the other."

To drive the point home, the group showed studies that suggest the proposed structure's minimal impact to salmon populations and big impact on reducing damage during major flooding events across the entire basin.

The structure as proposed would only hold back water at times when significant flooding is in the forecast, otherwise allowing the river to run free. It would be located near the headwaters in Pe Ell.

Concerning the expected impact to vulnerable fish, the group presented a trimmed down version of a presentation given to the Chehalis Basin Board in early April.

The data presented showed a comparison between how the proposed flow-though dam would impact salmon numbers across the basin with how it would impact the area studied in the state's draft environmental impact statement (EIS) released earlier this year.

The draft EIS published as part of the State Environmental Protection Act focused its study on the parts of the Chehalis River immediately impacted by the proposed flow-through dam. The study area begins near Rainbow Falls State Park and encompasses the rest of the river and its tributaries headed upstream toward Pe Ell.

The study found that the construction and operation of the proposed flow-through dam would contribute to reducing the population of vulnerable salmon in the area, with some, such as spring-run Chinook, disappearing entirely.

Graphs in the recent presentation show the numbers included in the draft EIS and suggest that fewer than 200 spring Chinook salmon that enter the study area would be hard hit by the new facility in the near term. It also shows that the species would likely disappear from the stretch of the river over the next 80 years under current conditions even without the facility.

The data presented to the city council and the Chehalis Basin Board predicts that even with some impact to the immediate area around the project, the flow-through dam would have a minimal impact on salmon populations across the basin.

"You don't see any difference with or without the project on the fish abundance of the Chehalis Basin," Vander Stoep said. "And that's the point."

The new basinwide abundance results provided in the original presentation to the Office of the Chehalis Basin in April predict that the flow-through dam would reduce vulnerable salmonid species, including coho, steelhead and spring-run Chinook, by less than 200 fish per year even by the late part of the 21st century.

Mysteriously, the study even shows that the dam might increase coho counts, with the predicted late-century coho counts with no flow-though dam showing 50,916 and counts with the structure predicted at 51,224.

To further back up their point, the group of long-time flood advocates compared two flood maps that predict the change in flood water depth after the construction of two different plans. The maps include the flow-through dam, an improved levee system around the Chehalis-Centralia Airport area and modifications to the Skookumchuck Dam to help retain flood water.

Another map shows the changes predicted after construction of the Local Action Non-Dam Alternative, often referred to as the LAND project. It proposes building a network of levees around Centralia, Chehalis and even Adna.

Vander Stoep pointed out on the maps that the levee system reduced flood water depth in protected parts of the two biggest cities in Lewis County, but also increased flood water depth outside of the levees and did nothing to help other towns. He added that the proposed flow-through dam and adapted Skookumchuck Dam were expected to temporarily hold 82,000 acre feet of water during catastrophic flood events.

The Centralia City Council has been openly supportive of the flow-through dam in the past and appeared to maintain that support Tuesday evening. Mayor Chris Brewer expressed support for the project and spoke of once again passing a public endorsement.

The Chehalis Basin Board is currently studying multiple options for addressing major flooding and diminishing fish numbers in the basin. Different combinations of project construction, including levees and the flow-through dam along with no action, are all currently being studied.

The board expects to make a final decision on what projects it will pursue by the end of the year.

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