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News from the Department of Water Resources (DWR)

Here is an update on the Lake Oroville Spillways Emergency Recovery project.

May 31, 2017

Community Members,

The following is an update from the Department of Water Resources on the Lake Oroville Spillways recovery project activities.

Two internationally recognized dam engineering and dam safety organizations released a statement Friday about the Lake Oroville spillway incident investigation. The Association of State Dam Safety Officials (ASDSO) and the United States Society on Dams (USSD) selected the independent Forensic Team members, who are charged with finding the cause or causes of the Lake Oroville spillway incident.

The statement describes the Forensic Team's process, discusses its preliminary findings and explains individual roles, including two members “selected for their expertise in how human and organizational factors may contribute to dam safety incidents.” The statement also provides contact information for media inquiries.

The Forensic Team is expected to submit their report expected in fall, 2017.

View the full statement here: http://www.damsafety.org/media/Documents/PRESS/2017/Oroville%20Press%20Release%20-%20May%202017.pdf

View the Forensic Team's bios here: http://www.damsafety.org/media/Documents/PRESS/2017/Oroville%20Investigation%20Team%20Resumes(1).pdf

And view DWR's press release here: http://www.water.ca.gov/news/newsreleases/2017/0530171.pdf.

For more information, follow us on TwitterandFacebookread our news releasesand visit our Oroville Spillway Incident webpage.

If you have questions please contact us at (800) 248-7026 or This email address is being protected from spambots. You need JavaScript enabled to view it..

– Oroville Outreach Team

COMMUNITY ADVISORY

TEST OF LAKE OROVILLE EMERGENCY SIREN

May 31, 2017

Please distribute this community advisory to your contacts or anyone who may be interested.

The public may hear a TEST of the Lake Oroville Spillways emergency siren this Friday, June 2 at noon.

 Although loud, this is only a test and is nothing to worry about. The siren test will lastless than one minute. 

The purpose of the siren is to alert construction workers about a worksite emergency, should one arise.

Future siren tests will be conducted at noon on the first Friday of each month. The next test will be July 7, then August 4, etc. Do not be concerned if you hear the siren.

This siren was installed recently to replace the siren that was lost during spillway releases in February. 

For more information about the Oroville Spillways, visit the California Department of Water Resources Oroville Spillway Incident webpage and/or follow us Facebook or Twitter.

 

If you have questions please contact us at (800) 248-7026 or This email address is being protected from spambots. You need JavaScript enabled to view it.

 

Construction

Construction on the flood control gated (main) spillway began on Friday May 19. Construction includes regular blasting to dislodge concrete on the chute of the damaged gated (main) spillway, as well as to safely lay back the slopes adjacent to the spillway to accommodate construction equipment. Blasting is a normal part of this construction process, and is not a cause for concern to residents or visitors. The blasting in this phase will be louder than previous blasts, however residents are not likely to hear it.

 Today, May 25th,  blasting will occur midday and early evening. For now, blasting will typically occur six days a week in the early evening.

 As a reminder, you can watch construction on the live “dam cam” https://www.parks.ca.gov/?page_id=29480

Siren

Some residents will recall that normal operation of the main spillway included the use of a signaling siren to alert anyone near the spillway and the adjacent Diversion Pool when the spillway was about to be operated. That siren was destroyed when erosion occurred next to the main spillway. DWR will replace the siren to restore the signaling function for future spillways operation.  This siren will also be used as part of DWR’s safety program to signal evacuation of the construction site should a construction emergency or safety incident occur. DWR will inform local law enforcement and the public when plans are in place to perform weekly safety drills that may include using the siren.

Lake levels

DWR understands the importance of keeping Lake Oroville at an adequate level to support summer recreation activities. We forecast the lake elevation to be lowered from the current level of 830 feet to 770 feet through the summer. We will balance the observed and forecasted reservoir inflow with necessary releases to manage a safe and reasonable lake level into the fall.

 Please visit www.water.ca.gov/oroville-spillwayfor more information, and to view photos and videos.

  Thank you,

 Erin Mellon, Communications Advisor

CA Natural Resources Agency

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On behalf of the California Department of Water Resources (DWR), I’d like to thank you for attending one or more of the recent community meetings about the Lake Oroville spillways incident emergency response and recovery. We appreciate your attendance and willingness to share questions, perspectives, and concerns.

We are reviewing and cataloging the written comments submitted at the community meetings, and will follow up where further details or clarification were requested. We plan to post written summaries of the community meetings on our website in June. 

DWR’s number one priority is public safety and security. We are committed to ensuring that the main (flood control) spillway is operational by November 1 to safely handle winter storms. We are working non-stop with our partner agencies to meet this objective.

We hope you will continue to stay engaged with DWR and members of your community during the recovery process. Please visit the DWR Oroville Spillways website or DWR Facebook pagefor project updates as well as notices of upcoming public meetings. You can reach us directly via email at This email address is being protected from spambots. You need JavaScript enabled to view it.or by phone at (800) 248-7026.

 Here are additional information resources:

 Community meeting PowerPoint presentation is available online.

Frequently Asked Questions

Who should I call with questions about evacuation procedures? Where do I find information on my evacuation zone or sign up for evacuation alerts?

In general, evacuation procedures and plans are developed at the county level and implemented by that county’s sheriff. DWR is in consultation with the Butte County Sheriff’s Department, along with other emergency and safety officials, to strengthen coordination and communications. Depending on the county you live in, a number of resources, including the ability to sign up for evacuation notices, are available:

 

Who is paying for the repairs?

Construction, operation and maintenance costs for Oroville dam are covered by the 29 State Water Project Contractors. FEMA may cover 75% of the eligible emergency response and Oroville dam complex repair costs. 

Why are there green spots on the face of the dam?

Oroville Dam is sound and safe. The green patches are caused by rainfall seeping into the face of the dam, allowing vegetation to grow. The seepage from the dam and the resulting vegetation is normal. All earthen dams have seepage. In fact, Oroville Dam had seepage as it was being constructed, even before the reservoir was full. DWR works with the Federal Energy Regulatory Commission to monitor the green patches.

Which government entities inspect the dam?

DWR continually assesses Oroville Dam. Oroville Dam is also formally inspected by three different entities.

  • Twice a year, the Dam is inspected by the California Division of Safety of Dams (DSOD). The last inspection by DSOD was conducted in August 2016.
  • Annually, the Federal Energy Regulation Commission (FERC) Dam Safety Program also inspects the Dam. The last FERC inspection occurred in May 2016.
  • Every five years, most recently in August 2014, an independent board of expert consultants inspects the Dam.

All of these inspections of Oroville Dam and its spillways concluded that they were safe to operate.

 Who is providing oversight of the recovery effort?

Oversight of the design and reconstruction of the Lake Oroville spillways is being conducted by several entities: Federal Energy Regulatory Commission, California Division of Safety of Dams, and the independent Board of Consultants. Each entity’s areas of jurisdiction are outlined on the DWR website.

When will we find out what went wrong with the spillways and why these problems were not anticipated?

To provide for an independent review of the spillways incident, DWR contacted the Association of State Dams Safety Officials and the United States Society of Dams to propose a team that could conduct a forensic evaluation. The assigned Forensic Team, comprised of six engineering experts with diverse specialties, is charged with determining the cause of the spillways incident, as well as any other contributing causes. Their findings will be shared with the Board of Consultants as they advise DWR on recovery operations so that lessons learned can be incorporated into the recovery plans.

Where can I find the memos or reports from the Forensics Team and the Board of Consultants?

This far, the Forensics team has released this memo outlining potential causes of the spillway incident. It is important to understand that not all of the factors listed in this memorandum will eventually be judged to have significantly contributed to the actual damages to the spillways. The team’s final report is expected to be released later in 2017.

Memos from the Board of Consultants are posted on DWR’s website here. The Board of Consultants memos provide a significant amount of information about the Lake Oroville spillways incident response and recovery, while protecting certain sensitive and security-related information.

Thank you,

Erin Mellon

Communications and Outreach Advisor

Natural Resources Agency