Oroville Dam Emergency Spillway Recovery
Photo ©Kiewit
Ninyo & Moore, a SOCOTEC Company, supported one of the largest emergency dam spillway reconstruction projects in U.S. history with materials testing and special inspection services, contributing to safety and resilience for millions of Californians.
Key Information
Client: State of California Department of Water Resources (DWR) c/o Kiewit Infrastructure West
Location: Oroville, California
Services Provided: Special Inspection, Materials Testing, On-Site Laboratories, Geotechnical Services
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The Challenge
Preventing a Dam Spillway Disaster in California
During the winter rains of 2016 and 2017, severe damage to the Oroville Dam spillway in Butte County, California, created an urgent crisis. Rapid erosion of the emergency spillway threatened dozens of downstream communities. Nearly 200,000 residents were forced to evacuate, and the State of California faced a critical task: stabilize and reconstruct the spillways to prevent catastrophic failure, and rebuild the ancillary roadways and parking areas around the dam.
The scale of the emergency demanded immediate, precise, and highly technical work. The California Department of Water Resources (DWR) needed partners who could mobilize rapidly and provide expert oversight for a project of unprecedented complexity. Ninyo & Moore, a SOCOTEC Company, was proud to support this historic effort by delivering materials testing and inspection services for Kiewit and DWR.
The Solution
Mobilizing Teams and Expertise for Reconstruction
To meet this challenge, Ninyo & Moore, a SOCOTEC Company, deployed a team of over 50 field technicians and ICC special inspectors to support DWR and its contractors in the multi-year reconstruction of the Oroville spillways.
Our team delivered comprehensive services between 2017 and 2020, including:
- Field Technician Staff rapidly deployed and assigned to the project.
- Materials Testing and Lab Testing for structural concrete, roller-compacted concrete, aggregates, various structural backfill, and asphalt pavement. These lab tests utilized two fully equipped on-site mobile laboratories, ensuring the rapid turnaround of test results and guaranteeing that construction could progress on schedule without compromising safety or quality.
- Special Inspections with ICC-certified inspectors of structural concrete during the construction of the new spillway
- Observation and Documentation of over 7,000 drilled anchor locations
The effort was monumental. Reconstruction involved more than 1.2 million cubic yards of roller-compacted concrete and 1 million cubic yards of structural concrete, requiring continuous monitoring and strict quality assurance.
To meet this challenge, Ninyo & Moore, a SOCOTEC Company, deployed a team of over 50 field technicians and ICC special inspectors to support DWR and its contractors in the multi-year reconstruction of the Oroville spillways.
Our team delivered comprehensive services between 2017 and 2020, including:
- Field Technician Staff rapidly deployed and assigned to the project.
- Materials Testing and Lab Testing for structural concrete, roller-compacted concrete, aggregates, various structural backfill, and asphalt pavement. These lab tests utilized two fully equipped on-site mobile laboratories, ensuring the rapid turnaround of test results and guaranteeing that construction could progress on schedule without compromising safety or quality.
- Special Inspections with ICC-certified inspectors of structural concrete during the construction of the new spillway
- Observation and Documentation of over 7,000 drilled anchor locations
The effort was monumental. Reconstruction involved more than 1.2 million cubic yards of roller-compacted concrete and 1 million cubic yards of structural concrete, requiring continuous monitoring and strict quality assurance.
The Results
Restoring Safety and Resilience
The Oroville spillway reconstruction stands as a testament to successful collaboration between public agencies, contractors, and geotechnical service providers such as Ninyo & Moore, a SOCOTEC Company. The project was an undeniable success:
- The main spillway was functional by November 2017, just months after the crisis, providing vital flood control ahead of the winter season.
- By 2018, the spillway was fully reconstructed and emergency spillway upgrades were completed to final design specifications, including the construction of a concrete buttress, underground secant pile wall, and erosion-preventing splashpad.
- The project engaged over 1,500 workers contributing more than 2 million labor hours, all under rigorous safety and quality standards.
- In 2020, the American Society of Civil Engineers (ASCE) recognized the project with the prestigious Outstanding Projects and Leaders (OPAL) Award, highlighting its importance to civil engineering and public safety.
The project's success ensured the continued operation of this vital hydropower facility. Most importantly, the communities of Oroville, Butte County, and California at large can now rely on strengthened infrastructure that safeguards lives, property, and the region’s hydropower resources.
Building Trust in Critical Infrastructure
This complex and large-scale geotechnical case underscores SOCOTEC’s expertise in critical infrastructure and energy sectors. Our geotechnical services and engineering capabilities, combined with our comprehensive testing and inspection services, make us the trusted partner for complex reconstruction and rehabilitation projects.
From dam and spillway reconstruction to roadways, parking, and hydropower facilities, our teams deliver the technical oversight that ensures infrastructure stands the test of time. By combining people-first values with advanced testing capabilities, we help our clients meet challenges with confidence.
