Home Depot Development on Rossman’s Landfill

(Oregon City, OR)  Landau Associates provided environmental and geotechnical engineering services for design and construction of the Home Depot store at the Rossman’s Landfill site, a closed municipal solid waste landfill in Oregon City, Oregon. Services included coordination with Oregon Department of Environmental Quality (DEQ) Solid Waste Program personnel during investigation, design, construction, and environmental monitoring activities.

Environmental services included leading agency coordination with DEQ; preparation of the environmental engineering design report that summarized existing site conditions and the key environmental design, construction, and monitoring provisions that were incorporated into site redevelopment; construction monitoring during excavation and disposal of refuse encountered during installation of pile foundations; and restoration of the soil cover in selected areas of the landfill.

Geotechnical engineering services included assisting in foundation design and the demonstration that driven pipe piles to support structural loads in underlying soft soil and refuse would not exacerbate groundwater contamination in the aquifer below the site. Landau Associates also designed an Ultrablock retaining wall that was founded over buried refuse extending under Highway 213. The wall was designed with discrete joints in order to accommodate differential settlement and to facilitate future removal and reconstruction if necessary. 

This project demonstrates how proper design and construction methods can be used to successfully construct a substantial development on a closed solid waste landfill, with waste left in place.