Flood Control Zone District supervisor Edna Fund discusses the district’s public comment regarding their proposed dam with district administrator Erik Martin Thursday, Nov. 12.
As the Army Corps works to finalize its Environmental Impact Statement (EIS) on the proposed dam in the Chehalis River, the Chehalis River Basin Flood Control Zone District is planning to formally submit a public comment arguing that the Corps has overestimated some negative impacts.
The district, which proposed the dam, is requesting that the Army Corps revise the EIS, this time taking into account the district’s own analysis and mitigation plans.
One potential impact of the dam — which would only close during flooding events — is reduced salmon populations. The Army Corps’ EIS, required under the National Environmental Policy Act, estimates a potential reduction of 40 to 78 percent of some fish populations in the project area. The district’s comments highlight the basin-wide impacts, however, which would be significantly less — in some cases projected population declines are less than one percent.
“What is lost in this presentation is that while the percentage of fish affected in the project area may appear high, the actual numbers of fish predicted to be lost are relatively few,” the document reads. “... including the actual predicted abundance values ensures that the (final EIS) will accurately reflect the potential basin-wide impacts which are not significant.”
The state Department of Ecology is responsible for a similar EIS required under the State Environmental Policy Act. While a draft has been completed, Gov. Jay Inslee earlier this year paused the process and asked the Office of the Chehalis Basin to come up with a viable alternative plan to the dam.
In public meetings hosted by the Army Corps, the issue of fish populations proved to be a point of contention, with some environmental groups arguing that even a small decline in salmon populations could have a precipitous effect on the ecosystem, including on southern resident killer whales, an endangered population that relies on the fish.
The district’s comments also point to assumptions the EIS makes about how often the dam would be closed, creating a reservoir that would inundate a large swath of land. The district’s comments argue that the Army Corps’ modeling made incorrect assumptions about frequency, extent, and duration of inundation, which “resulted in an overestimate of the increase in water temperature and resulting effect on aquatic species.”
Ultimately, the district is requesting that the Army Corps refines its analysis in seven different places. The comment also requests that the Army Corps use the district’s own data and analysis for their final draft, critiquing the Army Corps’ use of modeling.
“... (A)lthough models provide context to decision making regarding a proposed action, models are inherently a simplified representation of complex systems, and must rely on subjective interpretation of error bounds for their results,” the comment reads. “When model results are relied upon as fact, this can lead to a misunderstanding of the application of the models in the decision making process.”
The district is also asking the Army Corps to take into account mitigation efforts, including a new Conceptual Vegetation Management Plan, which outlines a plan to minimize tree clearing and vegetation removal during the project’s construction. Plans to mitigate environmental impacts by enhancing salmon habitat and spawning grounds are also underway.
On Thursday, the district met to discuss their planned public comment, which will be submitted in coming days. Erik Martin, the district’s administrator, noted that although Inslee requested last summer that the Office of Chehalis Basin (whose members overlap with the district) consider non-dam alternatives, he also told the office to continue analyzing environmental mitigation efforts for the dam.
“And that’s what the district has been doing since,” Martin said. “And it’s starting to show that many of these impacts can be mitigated in a very effective way … we are answering the governor’s call.”
Public comment on the Army Corps’ EIS is due Nov. 17 and can be submitted here: https://chehalisbasinstrategy.com/eis/nepa-process/.
