Skip to content
CapRadio

CapRadio

signal status listen live donate
listen live donate signal status
listen live donate signal status
  • News
    • topics
    • State Government
    • Environment
    • Health Care
    • Race and Equity
    • Business
    • Arts and Lifestyle
    • Food and Sustainability
    • PolitiFact California
  • Music
    • genres
    • Classical
    • Jazz
    • Eclectic
    • Daily Playlist
  • Programs + Podcasts
    • news
    • Morning Edition
    • All Things Considered
    • Marketplace
    • Insight With Vicki Gonzalez
    • music
    • Acid Jazz
    • At the Opera
    • Classical Music
    • Connections
    • Excellence in Jazz
    • Hey, Listen!
    • K-ZAP on CapRadio
    • Mick Martin's Blues Party
    • Programs A-Z
    • Podcast Directory
  • Schedules
    • News
    • Music
    • ClassicalStream
    • JazzStream
    • Weekly Schedule
    • Daily Playlist
  • Community
    • Events Calendar
    • CapRadio Garden
    • CapRadio Reads
    • Ticket Giveaways
  • Support
    • Evergreen Gift
    • One-Time Gift
    • Corporate Support
    • Vehicle Donation
    • Stock Gift
    • Legacy Gift
    • Endowment Gift
    • Benefits
    • Member FAQ
    • e‑Newsletter
    • Drawing Winners
    • Thank You Gifts
  • About Us
  • Contact Us
  • Close Menu
 We Get Support From:
Become a Supporter 
 We Get Support From:
Become a Supporter 

Oroville Spillway Final Report: 50 Years Of Inadequate Action

  •  Bob Moffitt 
Friday, January 5, 2018 | Sacramento, CA
Listen
/
Update RequiredTo play audio, update browser or Flash plugin.
CA - DWR / Twitter
 

CA - DWR / Twitter

The final report on last February's failure of the Oroville Dam spillway and resulting overtopping of the emergency spillway says there is plenty of blame to go around. 

A 584-page report by the Independent Forensic Team says a combination of poor design, complacent management, and insufficient response to the spillway's failure contributed to a scenario in which 180,000 people were ordered to evacuate.

The team's report says the California Department of Water Resources was "somewhat overconfident and complacent regarding the integrity of its civil infrastructure." Investigators also blame regulatory and industry practices.

This was in spite of the condition of the rock at the main spillway site. It was identified as "poor" by geologists before the chute was completed in 1968.

Investigators say the design and construction process failed to make proper modifications to fit the site conditions.

The report says the concrete slab cracked almost immediately above and below the drain pipes after it was built in 1968. The cracks and resulting "underdrain flows" were "quickly deemed to be 'normal.'"

The report says the contractor on the project had never built a spillway before.

Although there were frequent repairs made during the next five decades, they did not address the erosion under the slab that was occurring.

In February 2017, investigators say water found its way through cracks and joints in the main spillway chute slab. The water caused an "unexpected" amount of erosion and put enough pressure from underneath the concrete that a rupture occurred.

Investigators also say the Department of Water Resources then failed to have a "full understanding" of the consequences that would come from halting or limiting water releases from Lake Oroville after the damage to the spillway was identified.

The report says flows were limited to protect the powerhouse at the base of the spillway even though the threat to the powerhouse was "clearly diminishing."

The overtopping of the emergency spillway weir lead to "severe and rapid erosion downstream of the weir and, ultimately, the evacuation order."

The report says geologists' reports in the early 1960's showed part of the area below the emergency spillway was not made of hard rock and was prone to erosion. Somehow, the department came to accept as fact that the area below the emergency spillway was all solid rock, covered by three-to-four feet of earth.

The Department of Water Resources issued a statement that says, in part, "We will carefully assess this report, share it with the entire dam safety community and incorporate the lessons learned going forward." 


Follow us for more stories like this

CapRadio provides a trusted source of news because of you.  As a nonprofit organization, donations from people like you sustain the journalism that allows us to discover stories that are important to our audience. If you believe in what we do and support our mission, please donate today.

Donate Today  

    More about Oroville Dam

  • Oroville Dam

    Related Stories

  • California Department of Water Resources

    Oroville Dam One Year After The Spillway Crisis

    Wednesday, February 7, 2018
    On the first anniversary of the Oroville Dam crisis, reporters Bob Moffitt and Risa Johnson look back at how the California Department of Water Resources handled the aftermath.
  • Bob Moffitt / Capital Public Radio

    California Politicians Weigh In On Oroville Dam Report

    Tuesday, January 9, 2018
    California Assemblyman James Gallagher joins Insight to discuss the Oroville Dam crisis and how it was managed.

 department of water resourcesOroville DamOroville spillway

Bob Moffitt

Former Sacramento Region Reporter

Bob reported on all things northern California and Nevada. His coverage of police technology, local athletes, and the environment has won a regional Associated Press and several Edward R. Murrow awards.  Read Full Bio 

Sign up for ReCap and never miss the top stories

Delivered to your inbox every Friday.

 

Check out a sample ReCap newsletter.

Thanks for subscribing!

Thank you for signing up for the ReCap newsletter! We'll send you an email each Friday with the top stories from CapRadio.

Browse all newsletters

More Stories

Andrew Nixon / CapRadio

What’s left for California lawmakers to tackle in their final month

August 1, 2022

Rick Bowmer / AP Photo

What to know about monkeypox’s spread and finding a vaccine in Sacramento

August 1, 2022

Alain Jocard, Pool via AP

California declares state of emergency as monkeypox outbreak grows

August 1, 2022

Most Viewed

Northern California wildfires: Where to find updates on air quality, evacuations, and official information

A California man’s ‘painful and terrifying’ road to a monkeypox diagnosis

Abortion is still legal in California. Here are answers to questions about access in the state.

California coronavirus updates: How many animal species have been infected with COVID-19? Scientists are still trying to find out.

New variants, wastewater data, long COVID: What Sacramento region experts are watching

We Get Support From:
Become a Supporter

Most Viewed

Northern California wildfires: Where to find updates on air quality, evacuations, and official information

A California man’s ‘painful and terrifying’ road to a monkeypox diagnosis

Abortion is still legal in California. Here are answers to questions about access in the state.

California coronavirus updates: How many animal species have been infected with COVID-19? Scientists are still trying to find out.

New variants, wastewater data, long COVID: What Sacramento region experts are watching

Back to Top

  • CapRadio

    7055 Folsom Boulevard
    Sacramento, CA 95826-2625

    • (916) 278-8900
    • Toll-free (877) 480-5900
    • Email Us
    • Submit a News Tip
  • Contact Us

  • About Us

    • Contact Us / Feedback
    • Coverage
    • Directions
    • Careers & Internships
    • Mission / Vision / Core Values
    • Press
    • Staff Directory
    • Board of Directors
  • Listening Options

    • Mobile App
    • On Air Schedules
    • Smart Speakers
    • Playlist
    • Podcasts
    • RSS
  • Connect With Us

    •  Facebook
    •  Twitter
    •  Instagram
    •  YouTube
  • Donate

  • Listen

  • Newsletters

CapRadio stations are licensed to California State University, Sacramento. © 2022, Capital Public Radio. All Rights Reserved. Privacy Policy | Website Feedback FCC Public Files: KXJZ KKTO KUOP KQNC KXPR KXSR KXJS. For assistance accessing our public files, please call 916-278-8900 or email us.