​  Contracted construction teams complete the final steps of construction on the ogee weir within the Tule River Spillway at Success Lake, California, November 13, 2024.





 

Contact Information

For more information on the
Tule River Spillway Enlargement Project,
please contact us at:

Phone
(916) 557-5100

Email
spk-pao@usace.army.mil 

Mailing Address:
U.S. Army Corps of Engineers Sacramento District
Tule River Spillway Enlargement Project
1325 J Street, Room 1640
Sacramento, CA 95814

Success Lake, Richard L. Schafer Dam and the Tule River Spillway Enlargement Project

Richard L. Schafer Dam is located on the Tule River, about five miles east and upstream of the town of Porterville, Tulare County, California. An earthen dam 145 feet tall and 3,490 feet long, then-Success Dam and Lake were authorized as part of the Tule River Project under the Flood Control Act of 1944 and construction was completed in 1961. The reservoir has since provided flood risk management, water storage and recreation benefits for southern Central California communities.

The dam was renamed on October 1, 2019, to Richard L. Schafer Dam. Schafer was an integral and active member of the Central Valley water community for many years, serving as an active participant on numerous water boards and providing consultation for 13 different water management organizations. For more than 20 years, Schafer spearheaded the local effort to partner with the U.S. Army Corps of Engineers (USACE) to increase water storage in Success Lake. He passed away at age 95 in July 2021.

The dam was well-built using design standards that were current at the time of construction. Seismic reanalysis that began in 1992 indicated that the alluvial (loose soil or sediment) foundation underlying the dam is susceptible to liquefaction, which in a major earthquake could cause the dam to fail.

In 1999, Congress authorized USACE to study how to address seismic risk to the dam. The study revealed additional concerns about seepage and overtopping, requiring further study and funding authorizations. In late 2006, the Corps began limiting the amount of water stored in Success Lake to minimize flood risk to the public while USACE studied the dam and developed a solution.

New requirements and modifications to USACE's dam evaluation process since 2004 required additional analysis and a new type of report. Upon completion of this report in 2010, the USACE national dam safety program required the district to perform a baseline risk assessment, which is a comprehensive analysis of all the dam’s safety risks using the same methods now being applied to USACE dams throughout the nation. This re-evaluation demonstrated that the risk associated with liquefaction (dam failure during an earthquake) and seepage is significantly less than early study results indicated, and on April 11, 2014, USACE approved raising the operating restriction of the reservoir behind Schafer Dam to the then-maximum authorized storage capacity of 82,291 acre-feet of water, or a storage elevation of 652.5 feet.

Phase 1 construction of the Tule River Spillway Enlargement project began in September 2020 and was completed in February 2022. Phase II construction began in August 2022 and is scheduled to be completed at the end of 2024. Upon completion, the current authorized storage capacity of Success Lake will increase from 84,095 acre-feet of water to approximately 112,000 acre-feet, reducing flood risk and increasing water conservation capacity for the region.

The project’s major improvements include widening the spillway by 165 feet, construction of a 10-foot-tall ogee weir that spans the spillway, armoring of Frasier Dike and the HWY 190 bridge, and construction of a high-access boat launch.

Frequently Asked Questions

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Expand List item 26009Collapse List item 26009  Is the dam safe?

Schafer Dam is not in danger of imminent failure and is regularly inspected and monitored. The primary concern is overtopping in a huge flood and the public would get notice far in advance of this happening.

Expand List item 26010Collapse List item 26010  What improvements are USACE making at Success Lake?

The Tule River Spillway Enlargement Project includes widening the spillway an additional 165 feet, making the spillway approximately 365 feet wide, and constructing a 10-foot-high concrete Ogee Weir across the spillway, which will increase the reservoir pool by 28,000 acre-feet for joint-use flood control and irrigation water storage space.

When the project is complete, Success Lake’s storage capacity will be 110,300 acre-feet of water.

To accommodate the modified spillway, USACE will relocate the paved access road that currently passes through the spillway and  will armor a bridged section of California Highway 190 where it passes over the lake to account for the increased pool levels.

In 2018, it was announced that the Tule River Spillway Enlargement Project would be one of five Sacramento District projects to receive supplemental funding through Public Law 115-123 to fund short-term repair projects and long-term disaster recovery projects. With the addition of supplemental funding, the project is funded to completion.

In September 2021, Phase 1 construction of the Tule River Spillway Enlargement project began and was completed in February 2022. The second phase of the project began in August 2022 and is expected to be completed at the end of 2024.

Expand List item 26014Collapse List item 26014  What is the current pool level in Success Lake?

Access current reservoir status, monthly reports and historical water data since 1990 at http://www.spk-wc.usace.army.mil/. From the homepage, select “Midnight Reservoir Status”, then “COE”.

Expand List item 26008Collapse List item 26008  What's wrong with the dam?

Overtopping is the main threat that could cause the dam to fail. Overtopping results from a huge, although rare, flood (about a 1/13,000 probability in any year) that could fill the reservoir too quickly, leading to overtopping and erosion of the dam. During this extremely rare flood event, Schafer Dam is not tall enough to store such a high volume of water.

Through rigorous engineering analysis and investigation completed in 2017, seismic and seepage risks have recently been determined to be minimal concerns and Schafer Dam was reclassified to a lower risk classification, allowing the Tule River Spillway Enlargement Project to move forward.

Expand List item 26011Collapse List item 26011  When will construction be completed?

The first phase of construction began in September 2020 and was completed in February 2022. Phase II construction began in August 2022 and is scheduled to be completed in December 2024.

Contract Opportunities

Opportunity Status Award Date Posted On Response Date 
Construction - Phase II Awarded March 2022 June 3, 2021 July 8, 2021
Construction - Phase I Awarded May 2020