Intake Gate Replacement and Drilling Project

In December 2019, the Gifford Pinchot National Forest released a Notice of Proposed Action for the Spirit Lake Tunnel Intake Gate Replacement and Geotechnical Drilling Project.  At the project page, you can read the official proposed action, preliminary natural resource specialist and engineering reports, government-to-government letters, and all of the comments received during the 30-day public comment period.

Only those who submitted written comments will have eligibility to file an objection once the Environmental Assessment and draft Decision Notice is released for a 45-day objection period. The Draft Decision Notice and Environmental Assessment is expected to be released in March or April 2020.

Background: When Mount St. Helens erupted in 1980, a debris avalanche carrying 3 billion cubic yards of sediment formed a natural dam that blocked the outlet of Spirit Lake, where it had previously flowed into the North Fork of the Toutle River.  If this debris blockage were dislodged, an estimated 2.6 billion cubic yards of sediment would flow into the Toutle, Cowlitz and Columbia Rivers, causing massive damage and loss of life.

To assess possible lake control measures the U.S. Army Corps of Engineers (USACE) completed an Environmental Impact Statement in April 1984. The selected alternative was to construct the current tunnel through Harrys Ridge, which drains Spirit Lake water into South Coldwater Creek, flowing into the Nork Fork Toutle River. The tunnel is approximately 1.6-miles long and 11 feet in diameter. 

Read the Notice of Proposed Action News Release from December 2019

 





https://www.fs.usda.gov/detailfull/giffordpinchot/home/?cid=fseprd632713&width=full