Engineers keep an eye on Brightwater tunnel alignment in Bothell

Experts investigate ground settling, find no immediate safety risk

Engineers and construction experts responded quickly yesterday morning to a report of possible ground settlement in a residential neighborhood along the Brightwater tunnel alignment in Bothell.

King County and Brightwater contractor Vinci/Parsons/Frontier-Kemper, a joint venture, inspected small cracks in the driveways, walls and flooring of two homes above a section of the tunnel. In June 2008, Brightwater’s BT-2 tunnel boring machine passed 270 feet below the area, located at the intersection of 90th Avenue Northeast and Northeast 195th street.

Engineers inspected a house and evaluated ground conditions in the vicinity but found no indication of an immediate risk to property or public safety.

The county will continue working closely with its team of engineers and install monitoring equipment to watch for any signs of additional ground settlement.

Tunneling started at the Brightwater North Kenmore portal near the intersection of 80th Avenue Northeast and Northeast 195th Street in fall 2007. This tunnel extends nearly two miles, terminating at the Brightwater North Creek portal at Northeast 195th Street and North Creek Parkway in Bothell. About 1.5 miles of the tunnel has been completed.

More information about the Brightwater project is available on the Web at http://www.kingcounty.gov/brightwater.

Related information

Brightwater

King County Wastewater Treatment Division