Flood Authority continues to endorse flow-through dam for flood control

The Chehalis River Basin Flood Authority, made up of the communities and counties along the Chehalis and Skookumchuck Rivers from Lewis, Thurston and Grays Harbor counties, announced in a news release last week that it is continuing to endorse a flow-through dam for flood control.

The structure is proposed to be built above Pe Ell in the upper Chehalis River.

"We've looked at the alternatives carefully," Flood Authority Chair Edna Fund stated in the release. "Our communities are the ones that are hit hard when the giant rainstorms from atmospheric rivers trigger catastrophic floods on the Chehalis. That's why we've always supported a basinwide flood solution. The best science proves that this flow-through dam will reduce peak Chehalis river flood levels for every community along the river from Pe Ell to Aberdeen, including Interstate 5."

The Willapa Hills - the proposed location of the structure - are the source of the greatest rainfall and, therefore, floodwaters during winter storms in the Chehalis River Basin, the news release stated.

In February 2026, federal fish scientists with the National Oceanic and Atmospheric Administration (NOAA) issued their finding that the proposed flow-through dam poses little risk to Chinook and other salmon runs.

The structure will have open gates at the bottom allowing free passage for fish, and will only operate as a dam temporarily during catastrophic floods. The proposed site is also in the uppermost limits of documented salmon habitat in the basin.

"This new information from NOAA along with new information from fish modelling conducted by the state shows, once again, that fish runs are at risk of continued dramatic decline unless we continue with aggressive habitat work, and that decline won't be caused by the flow-through dam," Fund said.

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