Issue

Sutter County is protected from flooding by over 260 linear miles of levees. Approximately 70 miles of the levees that protect Yuba City and Live Oak from flooding have been improved but do not meet new, higher federal standards. Today, levees not only need to be high enough to hold anticipated water surface elevations relating to 1% probable storm events, but also have to be structurally sound enough to prevent or withstand through-seepage, under-seepage and rotational failures.

 Evaluation

Core sampling of the levees took place during 2006 and 2007 to identify levee reaches at risk. Evaluations using the sampling data are being used to help plan levee improvement projects.

Standards

FEMA requires that levee systems protect against the "100-year-flood" standard, meaning the levees would be strong enough to withstand a flood with a 1% chance of occurring in any one year. The State of California, Sutter County and Yuba City have set an additional goal of having levees to protect against a "200-year-flood" (0.5% chance of occurrence) for urban areas such as the cities of Live Oak and Yuba City.

Historical Perspective

Sutter County experienced major flooding 15 times during the 20th Century. Most recent levee breaks occurred in 1955 at Yuba City and Nicolaus; in 1986 at Linda and Olivehurst (both Yuba County); and in 1997 at Meridian and Arboga (Yuba County). Yuba City evacuated more than 24,000 residents prior to the 1997 event.

Responsibility

The Central Valley Flood Protection Board (CVFPB) owns and oversees all "project levees" developed as part of the federally-funded Sacramento River Flood Control Project. The U.S. Army Corps of Engineers shares regulatory oversight with the CVFPB. State Maintenance Areas and local levee and reclamation districts have responsibility for maintaining the levees.

Funding

The State and Federal Government provide some funding for flood protection. Even with passage of Propositions 1E and 84, the need is far greater than the available funding. Local governments are expected to share the costs. Cities and the County will explore options for raising necessary local shares.

Timeline

• Updated FEMA – Flood Insurance Rate Maps (FIRMs) for all of Sutter County are anticipated in 2016. The new FIRMs will reflect that the levees protecting Sutter County are no longer accredited, and will therefore trigger mandatory flood insurance for many Sutter County residents, affect insurance rates for current policy holders, and affect construction standards for new buildings.
• The Sutter Butte Flood Control Agency (SBFCA) is planning to improve 44 miles of levees from Thermalito Afterbay south to the Sutter Bypass. Design and environmental work was completed in 2012. Early stages of construction are expected to start in 2013, with project completion slated for late 2015. 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.