SCH Number 2022110165

Project Info

Title

Yuba River North Training Wall Phase 2 Project

Description

The North Training Wall (NTW) is an approximately 2.25-mile-long cobble embankment that was constructed by the California Debris Commission in the early 1900s to confine the Yuba River and facilitate downstream movement of mining debris within the floodway. Flood control was not an authorized purpose, but the NTW has historically provided and continues to provide flood risk reduction to the surrounding area. However, the height and width of the NTW have decreased over time. This reduction and ongoing, persistent erosion from storm events have combined to increase the flood risk to the Hallwood community, the City of Marysville, and portions of Reclamation District 10 (D-10). In early 2022, the Three Rivers Levee Improvement Authority (TRLIA) completed the NTW Phase 1 Project, which included reshaping the NTW embankment to provide a more stable geometry and address height and width reductions that had occurred over time and ongoing, persistent erosion from storm events. Completing this reshaping improved flood protection for the City of Marysville and portions of D-10 and substantially reduced flood risk to the community of Hallwood. The NTW reshaping was evaluated separately under the California Environmental Quality Act (CEQA) because it had independent utility and resources were available to complete the work. The Phase 2 project includes constructing a high ground tie-in embankment to extend the north end of the NTW upstream and form a contiguous line of protection that further reduces flood risk to the Hallwood community, the City of Marysville, and portions of D-10. Phase 2 also includes potential ecological enhancement components: riparian/aquatic habitat creation, fish passage enhancement, and salmonid foraging enhancement.

5 documents in project