Phone: 425.415.0551

Fax: 425.415.0311


Riley Group Corporate Office

17522 Bothell Way NE

Bothell, WA 98011

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City of Monroe

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Former Monroe Landfill

The Riley Group, Inc. (RGI) conducted an assessment of the horizontal and vertical extent of the former City of Monroe municipal solid waste landfill. The former City of Monroe landfill occupies 3 to 4 acres of an undeveloped, approximately 11-acre parcel located within the Monroe city limits.

RGI’s assessment began with a thorough review of the available City of Monroe, Snohomish County Health Department (SHD), and Washington State Department of Ecology (Ecology) files regarding the history of the landfill. RGI also reviewed available aerial photographs showing the landfill area.

To better estimate the area, thickness, and boundaries of the landfill RGI recommended a geophysical survey. The geophysical survey findings were used to map and field-flag the approximate edge of the landfill. RGI prepared a work plan to confirm the extent and thickness of the landfill material using an excavator and a sonic drilling rig. This plan was approved by SHD in June 2013 and completed in July 2013. A final report of findings was completed in October 2013. The City of Monroe is currently reviewing their options for developing or divesting the former landfill site.

RGI services included:

  • Conducting an assessment of horizontal and vertical extent of landfill
  • Reviewing historical documents
  • Coordinating third-party geophysical survey and interpretation of results
  • Preparing a report detailing findings, conclusions, and recommendations