Seattle: Damaged downtown water pipe must be replaced; expected cost $4M
SEATTLE (AP) — The director of the Seattle Public Utilities department says crews will soon start digging up Western Avenue in downtown Seattle to replace a quarter-mile of 20-inch diameter water pipe damaged last fall in the Pioneer Square neighborhood.
The Seattle Times reports http://is.gd/5iVWHh that agency director Ray Hoffman told the City Council on Monday the pipe must be fixed soon to reduce flooding risk from a rupture. Replacement is expected to cost $4 million.
The agency says the pipe has sunk as much as 1.3 inches in three measured locations.
The Times said the suspected cause was groundwater pumping by Seattle Tunnel Partners, the state contractor building the Highway 99 tunnel project.
The tunnel contractor needed to relieve water pressure that otherwise might blow into the concrete-lined, 120-foot-deep access pit that was built to reach the front end of the damaged tunneling machine called Bertha.
The newspaper says that hundreds of survey measurements by the state, contractors and city indicate the ground has stabilized since January.