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2008 Construction Work

The design, construction and operation of the 2008 cleanup actions are described in the 2008 Engineering Design Report (EDR). The report includes the construction activities, building relocation, traffic impacts, and construction sequence described below.

What is a hydraulic control and containment (HCC) system?
The HCC system will prevent contaminated groundwater from traveling north from the rail yard property. It includes an underground groundwater barrier and a trench to collect groundwater. Groundwater collected by the HCC will be properly treated and discharged in permitted locations.
What is compliance monitoring?
Compliance monitoring confirms that human health and the environment are always protected during cleanup activities. It also measures whether the cleanup meets cleanup standards.
What is air sparging?
Air sparging is designed to treat contaminated soils and groundwater. The air sparging system for the NEDZ will include sparging wells, underground piping, and blowers to supply pressurized air to the sparging wells. A mechanical building for the air sparging system will be located in the Railyard Zone.
Construction Activities
Rail yard Zone (RYZ)
  • Construct hydraulic control and containment (HCC) system underground on the south side of Railroad Avenue.
  • Construct water treatment system for groundwater recovered by the HCC system.
  • Construct new crossing under the BNSF mainline tracks for remediation systems.
  • Construct temporary water treatment facility to treat water from construction activities.
  • Perform compliance monitoring & restoration activities.
  • Perform soil screening, stockpiling and loading of impacted soil onto rail cars.
Northwest Developed Zone (NWDZ)
  • Excavate and restore Railroad Avenue
  • Excavate free product and contaminated soils on the Whistling Post Tavern, Town, BNSF, and McEvoy House properties.
  • Excavate a small portion of Skykomish Church property and 4th Street right-of-way.
  • Perform compliance monitoring & restoration activities.
Northeast Developed Zone (NEDZ)
  • Excavate and restore Railroad Avenue
  • Sample shallow soils for lead on the Johnson property and the Church property and remove contaminated soils if possible.
  • Excavate free product and contaminated soils on Raiload Avenue and Joselyn Property
  • Install air sparging system on the Joselyn property.
  • Perform compliance monitoring & restoration activities.
  • Monitor air quality in the crawl space of the house on the Joselyn property and install fans if needed to maintain air quality in the crawl space.
Building Relocation
  • The Depot, McEvoy House and Whistling Post Tavern will be relocated during cleanup activities.
  • After construction is completed, the McEvoy House and Whistling Post Tavern will be returned to their original locations and connected to infrastructure for the community wastewater system.
  • The Depot will be relocated to a new location decided by BNSF and the Town.
Traffic Impacts
  • The 5th Street and Railroad Avenue intersection will be closed for up to three months.
  • An alternate route will be provided across the railroad tracks for cars and pedestrians while the crossing at 5th Street is temporarily closed. Access across the tracks will be located across from the school and will be available from 7:00 am to 10:00 p.m.
Construction Sequencing
Phase I
  • Move Depot to temporary storage location and prepare McEvoy House and Whistling Post Tavern for moving
  • Install all utility bypasses
  • Construct temporary public crossing and temporary construction crossing for moving excavated material onto the rail yard
  • Construct HCC (temporarily close 5th Street crossing)
  • Complete additional shoring and excavation north of HCC while still maintaining a single lane of traffic on Railroad Avenue east of 4th Street
  • Install air sparging system on Joselyn property
  • Backfill the excavated areas
  • Open 5th Street to traffic
Phase II
  • Move McEvoy house to temporary storage on Railroad Avenue
  • Establish a driving surface on newly backfilled area next to the HCC and move Railroad Avenue traffic to that surface
  • Move Whistling Post Tavern to the west of its current location
  • Install shoring where required and complete remaining excavation
  • Backfill and return Whistling Post Tavern and McEvoy House to original locations
  • Complete restoration activities
  • Complete remaining HCC features, including water treatment facility
Want more information?
You can read the 2008 EDR, along with the Master EDR, Cleanup Action Plan (CAP) and other cleanup documents, at any time. Documents can be found at the following locations: