Brightwater tunnel mining now complete - two tunnels join under Lake Forest Park

Under Lake Forest Park, workers hose down the dirt coming through the wall as the cutting head 
breaks through the concrete wall separating the two tunnels.  Photo courtesy Brightwater.

Mining completed a month ahead of schedule; tunnel to begin operating mid-2012

The daily grind is over for the tunnel boring machine that on Wednesday, August 17, 2011, broke through the final sliver of earth 300 feet below Lake Forest Park to complete mining on Brightwater’s 13-mile conveyance tunnel.

Joint venture contractor Jay Dee Contractors, Inc. and Frank Coluccio Construction (JDC) signed the contract in April 2010 to complete the remaining 1.9 miles of the four-mile BT-3 tunnel, one of four tunnels in the Brightwater Treatment System’s 13-mile conveyance pipeline.

The contract called for JDC to complete mining on the 13.3-foot-diameter tunnel by September 2011. The estimated cost of the entire contract is $77.3 million, which includes $2 million in incentives for completing the mining work on time. The contractor is also eligible for additional incentives of up to $2 million for completing the remaining non-mining elements of the work early.

After the change of contractors to JDC, the cutting head on Elizabeth was brought up 

through the Ballinger Portal and refurbished before the machine bored the tunnel segment 

between Ballinger and Lake Forest Park. Photo courtesy Brightwater

With tunnel mining completed, JDC will now install the final lining on the adjacent four-mile BT-4 tunnel they completed last summer. The contractor will also build a sampling facility at Point Wells and connect the Brightwater conveyance pipeline to a mile-long marine outfall that was completed in 2008. JDC will also restore the 9-acre Point Wells portal site near Richmond Beach.

The 13-mile tunnel is scheduled to begin carrying treated wastewater from the Brightwater site to the deep-water outfall in September 2012.

Interim plan until the tunnel begins
operating.  Graphic courtesy BW.

King County originally contracted with Vinci, Parsons and Frontier-Kemper (VPFK) to build the BT-3 tunnel, but in mid-2009, the contractor’s “Rainier” machine was damaged and required time-consuming repair. Executive Constantine made a decision to hire JDC, which had completed the adjoining four-mile BT-4 from Point Wells to the Ballinger portal and already had a machine, “Elizabeth,” in place. VPFK remains under contract to complete the final tunnel liner in the BT-3 tunnel and to restore the Kenmore property that served as a staging area and access portal during tunnel construction.

The treatment plant will begin operating this summer and treated wastewater will be sent to South Plant in Renton or West Point in Seattle until the Brightwater tunnel begins operating. (see map)

The public is invited to a grand opening celebration of the Brightwater Treatment System project on September 24, 2011.