Ballard Siphon replacement project

February 9, 2012 Project Update

North site: Shoring installation is complete! After several weeks of site cleanup and preparation, crews will begin shaft excavation. 
El sitio del norte: ¡La instalación de la columna es completo! Después de varias semanas de preparación del sitio, los equipos comenzarán la excavación del eje.

South site: Shaft construction begins. Truck deliveries increase as equipment and materials are brought to the site.
El sitio del sur: La construcción del eje comienza. Aumentan las entregas de camiones como equipo y materiales son llevados al sitio.

View project update (PDF, February 9) 

Typical work hours: 7:00 a.m. – 6:00 p.m. weekdays
24-hour project hotline/Para más información*: 206-296-3848
  (*Señale su idioma y llamaremos a un intéprete. El servicio es gratuito.)

Project description

Project map. Click map to enlarge view. Also available as PDF


Construction Photos at the North Site (PDF), January 30, 2012

 
Pedestrian detour map (PDF), August 2011

To protect public health and the environment, King County is building a new 84-inch siphon pipe under Salmon Bay between the Ballard and Interbay areas of Seattle. The new siphon will be installed more than 120 feet underground and connect the Ballard Regulator Station at 5110 Shilshole Avenue Northwest in Ballard to the North Interceptor at West Commodore Way and 24th Avenue West intersection in Interbay (see project map).

After excavating vertical shafts at the Shilshole Avenue and Commodore Way sites, King County’s contractor will install a tunnel boring machine to bore a pipe corridor for the new siphon roughly 60 feet beneath Salmon Bay. The existing siphon will be cleaned out and relined as part of this project. Additional equipment supporting the new pipe will also be installed at the Ballard Regulator.

Project need

The new pipe is needed to accommodate growth in north Seattle. The new pipe replaces two 36-inch wooden stave pipes which have served the Ballard community since the 1930’s. The new pipe will meet north Seattle’s wastewater conveyance needs through the end of the century.

Wastewater from homes and businesses in Ballard now flows through the 36-inch siphons and across the bay, moving from the higher elevated pipes on the north side of the canal to the lower elevation on the south side, for treatment at the West Point Treatment Plant in Magnolia.

Project schedule

What to Expect

• Noise and other activity typical of a construction site at the intersection of Shilshole Avenue Northwest and Northwest 20th Avenue in Ballard and at the intersection of West Commodore Way and 24th Avenue West in Interbay.
• Crews, trucks and heavy equipment at the Ballard and Interbay sites
• Traffic detours near the construction sites on Shilshole Avenue Northwest and West Commodore Way.
• Increased truck traffic on Shilshole Avenue Northwest, 15th Avenue Northwest, Northwest Leary Street, West Nickerson Street and Aurora Avenue.