Army Corps of Engineers declares emergency for Yolo Bypass levee repairs after slope collapse

The West Sacramento Area Flood Control Agency (WSAFCA) held a meeting on December 19, 2024, to discuss urgent repairs needed at the Yolo Bypass following a significant levee collapse. The meeting began with an overview of the emergency situation, which was first declared by the Army Corps of Engineers on October 18, 2024, after a warranty walkthrough revealed a concave depression along the levee slope. This issue escalated to over a quarter of a mile in length, prompting immediate action.

The Army Corps of Engineers outlined their response, which included modifying a construction contract to build an adjacent levee behind the existing structure. This approach was deemed one of the most effective ways to ensure flood protection during the winter months. Initial efforts focused on excavating a keyway for the new levee, which required the relocation of a PG&E pole that previously supplied power to a nearby pump station operated by the California Department of Fish and Wildlife (CDFW). In the interim, a generator has been arranged to maintain operations at the pump station.

The contractor has been working diligently, securing necessary materials and constructing the adjacent levee. Additionally, the Corps has initiated the removal of rock from the slope to reinforce the levee toe and the edge of the Tule Canal, aiming to prevent further slumping. Geotechnical assessments are ongoing to determine the best long-term solutions for the levee's stability.

As of the meeting, the adjacent levee construction is complete, and protective measures using visqueen and sandbags are 40% finished, with expectations for completion in the coming days. The Corps is also evaluating whether a 4 to 1 slope may be more suitable than the standard 3 to 1 slope for this area.

Funding for these emergency repairs will be drawn from the Weibull account, and the Corps is currently working within the original budget estimates for the Yolo Bypass project. A contract amendment with REE is in progress, and a detailed cost estimate will be presented in the following month.

The meeting concluded with an emphasis on the urgency of the repairs and the collaborative efforts between the Army Corps of Engineers and local agencies to ensure the safety and integrity of the levee system.