I-405 Sepulveda Pass Widening

There is no more a central artery, or more trafficked freeway, than the 405 freeway in Southern California. Because of this, any attempt to repair or upgrade the 405 makes it a highly visible and scrutinized project. So, the Sepulveda Pass Widening was major news in California, being referred to as Carmageddon.

Chambers Group not only delivered environmental compliance monitoring for multiple construction crews on day and night shifts for this design-build contract, but we also developed a contractor education brochure to sensitize construction workers to environmental issues on the project. Staff conducted a formal jurisdictional delineation of the site in support of Clean Water Act (CWA) Sections 401, 402, and 404; and Division 2, Chapter 6, Sections 1600-1602 of the California Department of Fish and Wildlife (CDFW) Code for U.S. Army Corps of Engineers (USACE) and Regional Water Quality Control Board (RWQCB) permits. Chambers Group conducted biological species monitoring, including sensitive plants, vegetation communities, native trees, nesting birds, bats (day/night), and sensitive species constraints mapping. Right-of-way for this project was on both sides of the freeway along the 10-mile segment. Chambers Group conducted a native tree survey and mapped native trees that may be impacted during construction (trees were replaced at a ratio of 5:1.) In addition, Chambers Group surveyed potential areas for nesting birds and bats, rating potential areas for the upcoming spring; helped maintain the construction schedule by recommending to perform a constraints analysis to provide data on areas with moderate to high potential for nesting birds and/or bats; installed exclusionary devices to prevent nesting during the nesting season; scheduled the vegetation removal in these areas and designated areas for geotechnical boring outside the nesting season to prevent future potential delays in the schedule. This was a robust scope as intended, but it wasn’t until nearly two years into the project that the Chambers Group role expanded dramatically.

At that time, CDFW ordered an immediate stop work on this project. This meant that the enormous efforts of so many different agencies and companies would meet a likely stall of several months, resulting in millions of dollars lost in stagnancy, not to mention any potential implications for the project itself.

In just four working days, Chambers Group coordinated agencies to develop a workaround. Responding with multiple senior staff working literally around the clock, a Habitat Mitigation/ Monitoring Plan (HMMP) was developed. In response, CDFW released the stop work order and allowed project-wide work to continue under the conditions outlined in the HMMP. All told, in a stretch of less than one working week, the massive Sepulveda Overpass Widening project went from regular operations to full stoppage and back to full resume. The work that Chambers Group provided saved the client several months of delayed construction and millions of dollars.

While Chambers Group knows that stopping a project is never planned, one of the pledges we are proud to make to our clients is to keep your project moving forward. Under the most time impacted and pressurized of circumstances; Chambers Group was able to keep this project moving ahead.