Auburn Dam on the American River: Fact Sheet

Betsy Cody, Steve Hughes, and Shelley Price(1)
Environment and Natural Resources Policy Division
Updated June 6, 1996
96-447 ENR

Background

For more than 30 years, Congress has debated constructing a dam on the American River near Auburn, California. The Army Corps of Engineers recently identified three alternatives for flood control, with the Division office's preferred plan calling for construction of a 508-foot-high detention dam. Currently, two bills address the issue: H.R. 3270 supports construction of the dam, while H.R. 2951 opposes construction of any structure on the North Fork of the American River.

The American River descends from the Sierra Nevada crest to the largest river in California, the Sacramento. A 115,000-acre floodplain lies at the confluence, encompassing much of Natomas and Sacramento. Historically, this region has been prone to flooding. Approximately 400,000 people and 165,000 structures, including the State Capitol, are contained within the 400-year floodplain.

Congress authorized the Bureau of Reclamation (Department of the Interior) to construct the Auburn Dam on the North Fork of the American River in 1965. Construction began in 1967. An earthquake in 1975 caused the Bureau to evaluate the dam's quake-resistance and halt construction. Due to the delay and increasing environmental and cost-sharing concerns, construction did not resume. In 1986, severe flooding raised the issue of whether the region had sufficient flood protection. At the direction of Congress, the Army Corps of Engineers (Corps) along with the State of California Reclamation Board (Reclamation Board), and later the Sacramento Area Flood Control Agency (SAFCA), proceeded to study the issue.

Current Issues

In 1991, the Corps released a Draft Feasibility Report and Environmental Impact Statement/Environmental Impact Report (EIS/EIR) analyzing six alternatives for increasing regional flood protection. Subsequently, H.R. 5414 and H.R. 5584 were introduced in the 102nd Congress authorizing new construction for flood control. Environmental and some local groups opposed the bills, stating concerns over environmental and economic impacts; size and cost of the projects; potential expandability of the dam; and availability of less expensive, less environmentally damaging alternatives. Congress did not authorize new construction in 1992, but instead included language in the Department of Defense Appropriation Act (P.L.102-396) authorizing levee, channel, and pumping station improvements to provide the Natomas basin and portions of the lower Dry and Arcade Creek waterbasin with a minimum of 100-year flood protection. Under further direction from Congress, the Corps began work to reevaluate flood control alternatives for the Sacramento area.

In March 1996, the Corps released the final EIS/EIR for the American River Watershed Project. This report identifies three options for flood control:

• The Folsom Modification Plan: designed to maximize the level of flood control protection without: (a) increasing the objective release(2) to the lower American River, or (b) constructing an upstream storage structure. The plan would require modifying Folsom Dam, increasing Folsom Reservoir's storage capacity, and constructing and fortifying slurry walls and levees. Likelihood of flooding in any one year: 1 chance in 180. Initial cost: $399 million.
• The Stepped Release Plan: calls for structural and operational modifications to Folsom Dam and Reservoir and associated system of levees to accommodate an increased objective release rate from Folsom Dam. The plan would require modifying reservoir storage, constructing slurry walls and other channel and levee improvements, and fortifying and building additional levees. Likelihood of flooding in any one year: 1 chance in 235. Initial cost: $522 million.
• The Detention Dam Plan: calls for the construction of a 508-foot-high structure on the North Fork of the American River, the construction and fortification of levees and slurry walls, and over 3,000 acres in environmental mitigation. According to the Corps, it would provide the highest levels of flood protection and other benefits. Likelihood of flooding in any one year: 1 chance in 500. Initial cost: $949 million.

The Detention Dam has been chosen as the locally preferred plan by the Reclamation Board and SAFCA, and as the recommended plan by the Corps' Division office. Due to budget and cost-sharing concerns, however, the Corps' Chief of Engineers draft report does not recommend authorization; instead it recommends authorization of features common to the three plans. Without specifically supporting the other options, many environmental and other groups oppose the Detention Dam plan, arguing that flood control can be achieved through non-dam alternatives. Meanwhile, other local groups and interests firmly support the project.

Authorization for Sacramento area flood control was introduced April 18, 1996, as the Disaster Prevention and Fiscal Responsibility Act of 1996 (H.R. 3270). Legislation prohibiting the use of Federal funds for the construction of a dam on the American River at Auburn (H.R. 2951) was introduced February 1, 1996. Neither bill has been reported out of committee.

Endnotes

1. Under the supervision of Betsy Cody and consultation with Steve Hughes, Shelley Price researched and wrote this report
2. Objective release is defined by the Corps as the flow of water that can safely be conveyed by downstream channels.