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Previous Cleanup Activities
  2006
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  2008
  2009
  2010
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. Below is a summary of construction activities performed in 2008.

What is a hydraulic control and containment (HCC) system?
The HCC system prevents 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 is 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 required standards.
What is air sparging?
Air sparging is designed to treat contaminated soils and groundwater. The air sparging system for the NEDZ includes sparging wells, underground piping, and blowers to supply pressurized air to the sparging wells. A mechanical building for the air sparging system is located in the Railyard Zone.
Construction Activities
Rail yard Zone (RYZ)
  • Constructed hydraulic control and containment (HCC) system underground on south side of Railroad Avenue
  • Constructed water treatment system for groundwater recovered by the HCC system
  • Constructed new crossing under the BNSF mainline tracks for remediation systems
  • Constructed temporary water treatment facility to treat water from construction activities
  • Performed compliance monitoring & restoration activities
  • Performed soil screening, stockpiling and loading of impacted soil onto rail cars
Northwest Developed Zone (NWDZ)
  • Excavated and restored Railroad Avenue
  • Temporarily relocated the Depot, McEvoy House and Whistling Post Tavern
  • Excavated free product and contaminated soils on the Whistling Post Tavern, Town, BNSF and McEvoy House properties
  • Excavated a portion of Skykomish Church property and 4th Street right-of-way
  • Returned the McEvoy House and Whistling Post Tavern to original locations and connected to infrastructure for the community wastewater system
  • Performed compliance monitoring & restoration activities
Northeast Developed Zone (NEDZ)
  • Excavated and restored Railroad Avenue
  • Sampled shallow soils for lead on the Johnson property, no excavation was needed
  • Excavated free product and contaminated soils on Raiload Avenue and Joselyn Property
  • Installed air sparging system on the Joselyn property
  • Performed compliance monitoring & restoration activities

Formal cleanup documents, weekly reports, and newsletters that were produced during 2008 cleanup activities are available in the Documents section.