Flood prevention outweighs research in basin, officials say

LONGVIEW — Cowlitz County commissioners are endorsing a U.S. Forest proposal to re-establish a primitive road to Spirit Lake, saying that protecting downstream communities from flooding is more paramount than safeguarding scientific research in the basin.

Re-establishing the road from Windy Ridge to the south shore of the lake will enable drill rigs to access the area to take core samples of the debris blockage holding back the lake. It also would make it easier to replace the aging intake gate on the 1.5-mile drainage tunnel that keeps the lake at a safe level.

The commissioners are distributing a letter, which they approved Wednesday, to local area governments seeking their endorsement. Port of Longview officials considered the letter Wednesday but are awaiting revisions to address port-specific concerns before approving it.

Citing a 1983 U.S. Geological Survey study, the letter states: “An outburst flood of the lake could generate 2.4 billion cubic yards of sediment to downstream communities, producing a catastrophic event on par with the 1980s eruption. A flood of this magnitude would likely completely inundate the port of Longview and close the ports of Portland, Vancouver and Kalama for over a month.”

The letter suggests that the Forest Service maintain the road as permanent, “not temporary.” The road would follow the same route used in the early 1980s to build the drainage tunnel and support a temporary pumping effort. That “should limit the idea that re-establishing that route is going to dramatically impact ongoing scientific studies,” the letter says.

“While we can certainly sympathize with any impact the project may have to studies in the area, we can hardly side with those concerns over the consequences of not being able to access the lake, understand the debris blockage, and maintain long-term safe lake levels.”

The May 18, 1980, eruption of Mount St. Helens blocked Spirit Lake’s old outlet into the North Fork of the Toutle River and raised the lake about 200 feet. Without an outlet, the lake would rise, break through the debris blockage and cause unprecedented flooding along the Cowlitz and Toutle valleys, scientists warned. So the U.S. Army Corps of Engineers cut a drainage tunnel that opened in 1985 to control the lake level.