Construction glitches may delay Brightwater

Glitches in construction of the Brightwater sewage-treatment plant and a treated-waste pipeline tunnel could delay the planned 2010 opening of the plant, a consultant told a Metropolitan King County Council committee Wednesday.

The consultant, R.W. Beck, also bumped up its cost estimate to at least $1.84 billion. Beck raised the low end of the cost range from the previous $1.83 billion and left the high end unchanged at $1.86 billion.

But the price could go higher if contractors run into unexpected problems in digging a 13-mile-long tunnel — up to 430 feet deep — that will take treated sewage to Puget Sound.

"There is always the risk in tunnels that they are going to encounter something major and unforeseen despite all the geotechnical work that was done," Beck senior director Pat Tangora said after a meeting of the County Council's capital-budget committee.

King County's budget for the project remains at $1.77 billion, but Project Manager Gunars Sreibers said the budget will be recalculated this spring. Brightwater, under construction near the Highway 9-Highway 522 interchange north of Woodinville, will treat sewage from customers in North King County and South Snohomish County when it is completed in late 2010 or early 2011.

Beck representatives said it is too early to say for certain whether construction problems will push back opening of the plant.

Even the Iraq war is figuring into the delay.

Work on the eastern segment of the tunnel is more than four months behind schedule, Beck reported. The start of construction initially was held up when the tunnel contractor couldn't obtain ball bearings for a boring machine because the Defense Department had requisitioned the entire output of the ball-bearing manufacturer for the war.

Since the contractor began work, tunneling through unstable peat under Northeast 195th Street in North Creek has gone slower than expected.

Another contractor took longer than scheduled to place closely spaced steel rebar intended to protect buildings from damage in an earthquake. That delay has used up nearly all of the "float," or cushion, in the construction schedule, Tangora said.

Sewer-utility managers say the Brightwater deadline is important because the risk of storm-related overflows of a Kenmore-area sewage pipeline will continue to rise until the plant begins operating.

The cost of Brightwater was originally estimated at $788 million in 1998 dollars, or $1 billion with inflation added.

Keith Ervin: 206-464-2105 or kervin@seattletimes.com