Earthwork

This extensive project included 250,000 CY of subgrade and ponding area excavation, 500,000 CY of embankment fill, 25,000 TN of riprap slope protection and a 300’ wide spillway. It also included installation of double 4’x6’ steel flap gated concrete box culverts and a concrete V-ditch. The finished improvements included over a mile of armored levee surrounding the Prison facility and raised the flood protection from the Prado Dam Reservoir up to an elevation of 566 feet.

Pillar Point Air Force Station is located on a 55 acre parcel of land 20 miles south of San Francisco. Adjacent to the community of Half Moon Bay, the site is positioned on a point of land 175 feet in elevation with steep bluffs overlooking the Pacific Ocean. The radar and telemetry station located there is critical for tracking, monitoring and control of missile tests emanating from the Vandenberg AFB missile and rocket launch sites.

Serious hydro-erosive activity jeopardized facilities and infrastructure located on the property.  A North Star Construction crew was deployed to the area quickly clearing and establishing a temporary road to access the steep incline to be repaired and shored. This project included replacing a failed 24” CMP down drain pipe with fused HDPE pipe. The project also included stabilization of seaside bluffs and reconstructing the primary facility access roadway.

The safe, effective, and efficient implementation of North Star resources and capabilities reversed the damage done to the hillside and vastly improved the drainage infrastructure of this strategically important and environmentally critical location for the foreseeable future.

Heavy rain events caused two large creep landslides and one complete road failure along Mosquito Ridge Road, located in the Tahoe NF. Immediate restoration of the road was essential as it is the only road used to service and maintain a large hydropower facility.  The two creep slides were repaired by installing over 3,500 LF of micropiles to arrest movement observed in the road prism. The third site required a more robust repair including the installation of a unique gabion retaining wall/drainage system in conjunction with stabilizing micropiles. The new retaining wall was built with a series of riprap- filled gabion baskets and a roadside under drain to capture sub-surface water. Other project features included a sheet drain system, overside drains and covering the hillside with High-Performance Turf Reinforcement Mat.