RENTON, Wash. -- Call it Boeing's berm.

The aerospace giant is taking sandbagging to another level.

In an attempt to avoid flooding from the Green River, a Boeing contractor is constructing an 8-foot-high berm of sand poured into a framework of thick canvas and wire.

It's tens of thousands of feet long, and surrounds two key complexes - Boeing's flight simulators at Longacres in Renton, and its complex in Kent that houses several national security defense programs and critical data center.

"It's a risk, and we've got to do things (so) that we are adequately protecting our assets and allowing us to continue on with business," said Dave Komendat, the company's chief of security.

The risk is a potential flood-level release of water from the troubled Howard Hanson Dam. The Army Corp of Engineers now says there's a one in four chance that may happen later this winter.

"When you look at what we are trying to protect, it's well worth the investment," said Komendat.

The company has not said how much the project will cost, or how long the berm is going to stay up.

The past week brought the first significant rain of the season, and what happened at the dam last week may be a snapshot of what's to come.

On Monday the level of the reservoir started to drop significantly as the Army Corp of Engineers increased its water release in preparation for the storm. And starting Sunday morning, the rain waters began pouring into the reservoir.

Boeing hopes to have its berm completed by the end of the month.