Ballard Siphon replacement tunnel - TunnelCast

31 October, 2013: Construction work to replace wood-stave wastewater siphons built in 1935 under the Lake Washington ship canal in Seattle, Washington, is entering its final phases with the final 84in (2m) diameter fiberglass reinforced liner pipe being installed into the completed 2,000ft (610m) long x 2.6m diameter tunnel excavated by an EPBM at about 18m beneath the bed of Salmon Bay. Application of innovative shaft sinking technology is one of the highlights on the successful job as explained by Marty Noble, Project Representative for owner King County, and Rich Mascarello, Project Manager for contractor JW Fowler. The new CSO wastewater tunnel is on schedule to begin operation in early 2014.

Seattle mobilizes for sewer upgrade - TunnelTalk, Sept 2011
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Ballard Siphon replacement project

Sterling Noren reporting for TunnelCast
Salmon Bay, Seattle, Washington
2,000ft long (610m) up to 120ft (37m) beneath the Lake Washington ship canal
CSO wastewater tunnel to replace a pair of wood-stave siphons, built in 1935
King County Department of Natural Resources and Parks Wastewater Treatment Division
Project Value:
$38 million
Contract Value:
$32.7 million
Launch shaft:
145ft deep x 30ft diameter (44m x 9m)
Reception shaft:
100ft deep x 70ft diameter (30.5m x 21m)
2.6m diameter Herrenknecht EBPM
Herrenknecht VSM (vertical shaft machine)
JW Fowler Company of Oregon
TetraTech & Staheli
Construction Management:
Jacobs Associates