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No sediment studies will be needed for Jacksonville dam removal

Plans to notch Jacksonville Reservoir dam passed a big hurdle when the U.S. Army Corps of Engineers ruled last month that sediment studies to determine chemical contamination are not required, says the project's planner.

Savings without the study requirement will be in the tens of thousands of dollars, said Scott English of Ashland, whose Northwest Biological Consulting firm is doing design work for the city.

"I think primarily one of the reasons we weren't required to do any more is that this is not an industrial area," English said. "Because this is €¦ not in an urbanized area makes it a lot easier to make this call."

Jacksonville is under pressure from the state to remove the dam, which has been labeled a hazard for people and property below it on Jackson Creek and is likely to fail in a major flood. The City Council has set aside $50,000 for studies on breaching the dam and $150,000 toward the work. The dam was built in 1912 but hasn't been used for water storage since the 1950s.

"It looks like we have passed a milestone on the sediment evaluation," Joe Sheahan, a project manager with the Corps, wrote to English in an email. One of the big issues will be how to control sediment moving in the event of a flood, he added.

"The next step is more detailed surveying and engineering design for breaching to the extent necessary to restore the creek," said English.

The Corps of Engineers and the Oregon State Division of Lands will need to issue joint fill and removal permits for the process after studies and reviews by multiple state and federal agencies.

"You really have to involve a lot of different agencies plus stakeholders as well," said English. He expects public meetings on the process and presentations to the City Council.

A project description calls for removing about 30,000 yards of sediment and rock and using some of the material to restore the natural flow of the creek from the dam base to the natural channel upstream. Excess materials would be placed in an adjacent quarry site from which rock for the dam was originally mined.

— Tony Boom

Read more in Saturday's Mail Tribune.