Forest Service lists two top options for Spirit Lake outflow in draft EIS; Cowlitz County staff to prepare briefing before comment deadline

Public Services staff asked the Board of County Commissioners for direction on how extensively the county should analyze the Forest Service draft Environmental Impact Statement (EIS) for the Spirit Lake outflow and said the Forest Service has identified two leading alternatives.

Mike Moss said the Forest Service's two top choices are: (1) repair and restore the historic Spirit Lake tunnel to a capacity of about 550 cubic feet per second (CFS); or (2) install a pressure (steel) pipe for primary outflow, perform minor tunnel rehabilitation, and construct an overflow channel to reconnect the North Fork Toutle (transcript used "Toodle") to Spirit Lake while routing the primary outfall through the new pressurized line. "Their 2 top choices are 1 is repair of the tunnel, and making that, restoring the capacity to 550, CFS. And then their other top choice is to install a pressure pipe, do minor rehabilitation of the tunnel, and start building in overflow channel to reconnect the North Fork Toutle to the Spirit Lake," Moss said.

Moss provided technical details cited in the draft: the tunnel length is about 8,460 feet with an 11-foot diameter; staff noted a current maximum outflow of about 400 CFS in its present state. Moss said the Forest Service's alternatives analysis identifies environmental effects and that "the responsible official will decide which primary and redundant outflow measures ... to construct," meaning the Forest Service will recommend and the Corps likely will carry out construction. Moss told the board the U.S. Forest Service owns the tunnel and the U.S. Army Corps of Engineers (Corps) has historically maintained and would likely construct the fix; funding and final authorization would involve federal decisionmakers and appropriations.

Moss asked the board whether staff should prepare a comment letter to the draft EIS and how detailed staff's background research should be prior to the public comment deadline (Moss said the draft EIS comment window is due in October). Commissioners on the dais urged the county to take an active position: several commissioners emphasized the need for a systemwide river study and for dredging as part of any long-term solution, cautioning that past data (from the 1980s) may not reflect current sediment dynamics. Board members discussed tradeoffs: the steel pressure pipe option was described as more resistant to seismic activity than a rehabilitated tunnel; a natural overflow channel would create a second outfall and put flows into different downstream routes.

Why it matters: Spirit Lake outflow decisions affect downstream river dynamics, sediment transport, flood risk and long-term channel evolution in the Toutle/SRS system. County staff requested guidance to prepare technical background and potentially a comment letter to the draft EIS.

Ending: Moss said he and a colleague (Patrick) will gather background and return to the board; commissioners asked staff to be prepared to recommend which alternative the county should support if the board chooses to submit comments before the federal deadline.