Northrop Rural Residential Site Design – Washington County, Oregon

LEI Engineering and Surveying of Oregon developed a complete site design for this rural homesite on steep terrain in Washington County, Oregon.

At the onset of this development project, LEI Engineering and Surveying of Oregon worked closely with the project architect, geotechnical engineer, and owner to develop a site layout that met the owner’s desire for the site, while addressing the challenges present at the site.  One of the major challenges of this site was the very bad soils identified by the geotechnical engineer.  To address the bad soils at this site; LEI Engineering and Surveying of Oregon minimized embankment heights, over-excavated unsuitable soils, and prescribed controlled compaction under the direction of the geotechnical engineer.

Another challenge at this site was the treatment of stormwater.  The steep terrain and poor soils with very low permeability meant that low-cost infiltration systems would not work here.  LEI Engineering and Surveying of Oregon designed a large, but shallow, detention pond with a staged control structure and a designed flow spreader.  LEI Engineering and Surveying of Oregon’s pond design treats site stormwater and outlets it downslope as sheet flow using the designed flow spreader.