by Neil E. Thompson, Superfund Proj. Mgr.; EPA, Seattle, WA,
Robert L. Stammes, P.E., (M.ASCE), Reg. Engr.; EPA, Seattle, WA,
Mark A. Koelling, P.E., (M.ASCE), Area Mgr.; Hayward Baker Inc., Seattle, WA,

Serial Information: Civil Engineering—ASCE, 1997, Vol. 67, Issue 12, Pg. 41-43

Document Type: Feature article


A Superfund site near Seattle was surrounded by a 2,200-ft-long soil-bentonite wall to keep contaminants from entering nearby water sources. An earlier remediation effort had failed to contain leakage of contamination from the Queen City Farms site, which was previously a hazardous waste dump. Complex geology and topography at the site complicated the new remediation effort and resulted in extensive earthmoving and construction of stepped working platforms to build the 40-70 ft deep barrier. An extended-stick backhoe trenched the entire length and depth of the wall location, and a bentonite slurry prevented the narrow trench from collapsing until the backfill material could be added. The finished wall has very low permeability and will protect against further migration of contaminants into soil and groundwater.

Subject Headings: Walls | Permeability (soil) | Waste sites | Soil pollution | Pollutants | Mitigation and remediation | Occupational safety | Construction sites | United States | Seattle | Washington | New York | New York City

Services: Buy this book/Buy this article


Return to search