Feather River West Levee Project
The Sutter Butte Flood Control Agency is planning to improve 44 miles of levees from Thermalito Afterbay south to the Sutter Bypass (project map). The goal of the project is to reduce flood risk and remove more than 34,000 properties from FEMA Special Flood Hazard Areas. Levee repairs will be completed in two separate phases (see Timeline below).
Levees along the west bank of the Feather River do not provide 100-year flood protection (protection against a flood that has a one percent chance of occurring in any given year), because they suffer from potential underseepage and through-seepage. Similar problems caused major levee failures in Yuba City in 1955, and Yuba County in 1986 and 1997.
Levees can be made stronger by building deeper cutoff walls (also known as slurry walls), stability berms and seepage berms. These levee improvements block or slow the flow of water through and underneath the levees. Not all 44 miles of levees will need each of these improvements. More than 80 percent of the needed levee repairs will involve the construction of slurry walls, some as deep as 110 feet. In a few select areas, seepage berms constructed on the land side of the levee were determined to be the best fix.
The levee improvement program is expected to:
- Increase public safety by providing 200-year flood protection to Biggs, Gridley, Live Oak, and Yuba City, and improve flood protection for the less populated areas south of Yuba City.
- Save property owners tens of millions each year in mandatory flood insurance costs by delaying, preventing, or cutting short FEMA floodplain mapping.
- Allow cities and counties the freedom to implement general plans, which will soon be severely restricted for any urban or urbanizing community without 200-year flood protection. This would not apply to rural communities (areas with fewer than 10,000 residents).
- Maintain the rights of property owners to make substantial improvements to property without new state or federal land use restrictions.
- Sustain and grow the local economy by creating construction jobs, protecting property values, and allowing for responsible residential, commercial and industrial development.
Levee repairs will be completed in two separate phases:
- Phase I, the Feather River West Levee Project, will include work from Thermalito Afterbay to Star Bend, just south of Yuba City.
- Phase II will include the area south of Star Bend to the confluence of the Feather River and the Sutter Bypass. Phase II work includes repairs to the Sutter Bypass, and is in the planning stages.
The Feather River West Levee Project is on schedule and within budget. Agency engineers are working on the levee project design and preparing requests for necessary permits from state and federal agencies. Environmental specialists are also collecting information that is needed for environmental permit approvals. Design and environmental work is expected to be completed in 2012. Early stages of construction are expected to start in mid-2013, with project completion slated for late 2015.
Costs for the Feather River West Levee Project are being refined, based on ongoing studies. The most recent cost estimate – $312 million – reflects funding for the Feather River West Levee Project and Phase II work, and will continue to evolve as the project design is finalized and funding agreements with the state are negotiated. At this time, the state is expected to pay for as much as 77 percent of the project costs for the Feather River West Levee Project, and property assessment revenues (approved by property owners in June 2010) will be used to pay the remaining share. The State recently awarded the Agency a $9 million grant to help pay for the Feather River West Levee Project design.