Issaquah Highlands

NGA was the lead geotechnical consultant on the Issaquah Highlands Master Development. Our services included numerous geotechnical evaluations for several different phases and aspects of this development, including slope and roadway stabilization, residential plats, retaining walls, roadways, and utilities.

NGA also worked with King County during their negotiations with Lake Side Gravel to acquire the right-of-way access for Highlands Drive. One of the most challenging aspects of this project was the stabilization of an ancient landslide that was traversed by the main road entering the development in the south side (Highland Drive).

This effort entailed an extensive geotechnical engineering analysis of the subsurface conditions and a design of a subsurface retaining wall. We monitored inclinometer casings installed in the vicinity of the repairs to ensure no additional movement of the road was experienced.

Location: Issaquah, WA