Marmot Dam will crumble to improve Sandy River salmon run

ALONG THE SANDY RIVER - In what is being called the 'biggest environmental event' of the decade, the century-old Marmot Dam on the Sandy River will be blown up to protect endangered salmon.

After a decade of planning, the countdown is on to bring down the 47-foot tall dam, which is owned by Portland General Electric.

Holes will be drilled 10 feet deep into the dam and 500 pounds of dynamite will be set off in more than a dozen successive charges, all lasting just a few seconds.

"It'll be a loud bang and there will be a lot of smoke and noise," said Project Manager John Esler.

The blast is expected to create a 40-foot opening across the dam's crown and heavy equipment will then go in to start to push the material out and cut the rebar.

All of this brings to mind another famous blast in PGE's recent past - on May 21, 2006, about 2,000 pounds of dynamite reduced Oregon's first and only nuclear plant to a 41,000-ton pile of rubble.

So how will the Marmot Dam blast compare?

"Well, this is going to be pretty anti-climactic, unfortunately," said Jerry Dilley, Manager with Superior Blasting.

That is because huge steel and rubber mats will be placed over the blast zone to keep debris from flying all over the river.

Although everyone will be kept 1,000 feet away from the controlled blast, project coordinators have made special plans to give them a show.

"At a thousand feet, it's pretty tough to see much in a controlled blast, so we're going to add some visual effects so they can actually see something happening," said Dilley. "We've set up some noisemakers, plus there will be material that will be thrown up in the air."