EVERETT — The deadline to comment on study plans for a proposed dam on the Skykomish River is Wednesday.
The Snohomish County Public Utility District is considering building a mini-dam on the river above Sunset Falls near Index.
The PUD has submitted a plan to the federal government specifying which environmental issues it will study in determining whether to build it. Those include water quality, fish passage, geotechnical issues, air quality and specifics within each category.
The power to approve or deny a permit for the project rests with the Federal Energy Regulatory Commission. First, the agency must approve the PUD’s study plan.
After the comments are in, FERC is expected to give a thumbs-up or down to the study plan by the end of the month, PUD spokesman Neil Neroutsos said.
The dam, if built, is expected to cost between $110 million and $170 million and supply power to an average of 10,000 homes.
The utility buys more than 80 percent of its power in the form of hydroelectric energy from the Bonneville Power Administration and is looking to diversify.
The project has met with stiff opposition from environmental organizations and some people who live near the site.
Concerns include flooding above the dam and reduced water flow below it, including possible effects on fish, glare from lights, noise and traffic during construction, and the effect on scenery.
According to a preliminary PUD study, the dam won’t cause flooding or de-watering on the river and will be visually unobtrusive. Detailed fish studies remain.
The plan involves diverting water from the pooled area behind the 7-foot weir above Sunset Falls on the south fork of the Skykomish, through a 2,200-foot pipe downstream to a powerhouse below the falls.
The weir would be inflated for about nine months of the year, when flow is highest, officials have said. It would be deflated during low-flow periods in the summer.
The PUD has not formally applied to build the dam. It will likely be at least five years before a final decision is rendered, a FERC official said last summer.
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