Michael McGinn, the only major candidate for mayor of Seattle who opposes Greg Nickels’ $4.2 billion plan for a bored tunnel, today challenged Nickels to acknowledge the lessons that he should be learning from the Brightwater and Beacon Hill tunnels.

“At $4.2 billion, the tunnel already costs too much and harms Seattle’s real priorities,” McGinn said. “And anyone who has seen what has happened with the Brightwater and Beacon Hill tunnels knows that the costs could rocket even higher.”

McGinn continued, “Greg Nickels needs to be honest with the voters of Seattle: there will be cost overruns, which Olympia requires Seattle taxpayers to cover.”

The recent setbacks with the Brightwater and Beacon Hill tunnels teach a clear lesson: digging a tunnel is complicated, expensive work, and it is inevitable that there will be cost overruns and delays.

On Sunday, the machine boring a two mile sewer tunnel for Brightwater  was damaged.  Because it is 300 feet beneath the surface, repairs must be done by divers operating under high pressure and the threat of the “bends.”  Repairs will take months.

Tunneling for the Brightwater sewage treatment plant caused a huge sinkhole to open at the surface, causing severe damage.  Sound Transit has fared little better with its bored tunnel through Beacon Hill, which caused several “voids” in the soil as well as a 21-foot-wide sinkhole beneath a home.

How do the Beacon Hill and Brightwater tunnels compare with Nickels’ tunnel?

By the state department of transportation’s own admission, the troublesome glacial soils and sands of Beacon Hill are exactly like the material beneath downtown Seattle where a tunnel would go.  But instead of the single-family homes and empty earth above the tunnels in Beacon Hill and rural King County, Nickels’ tunnel would be bored beneath office towers, the bus tunnel, the railroad tunnel, sewage lines, and utility lines.

And the Brightwater and Beacon Hill projects suffered delays and cost overruns despite being far less complicated projects. At 54 feet wide, Nickels’ tunnel would be the widest bored tunnel in the world. By way of comparison, Sound Transit used a 21-foot-wide boring machine, and yet costs “exceeded the initial estimate by nearly 31 percent because of unstable soil and water discovered after the work began,” according to a news report.  Similarly, the Brightwater sewage treatment plan will cost at least $1.8 billion—twice as much as originally promised, and the cost estimate seems to go up every year.  Sunday’s sinkhole was caused by a boring machine only 16.5 feet wide —less than a third of the width of the machine that would be necessary for Nickel’s tunnel.

“The establishment insists that this is a done deal,” McGinn observed. “But at this point, it’s still just a costly fantasy, and if I am elected mayor, I will work to make sure that it never becomes a reality.”