Posted by: Deirdre Des Jardins | June 26, 2017

WaterFix Dual Conveyance Operations Permit Deferred

Tunnel map

In a major change from the draft Biological Opinion, most of the Final Biological Opinion by the U.S. Fish and Wildlife Service is programmatic only.   No Incidental Take Permit for operations of the State Water Project and Central Valley Project under Dual Conveyance has been issued. The cover letter does state that the U.S. Fish and Wildlife Service has concluded that the project is unlikely to modify critical habitat.

DFW application status unclear

The change also makes the status of the application by the Department of Water Resources to the California Department of Fish and Wildlife for an Incidental Take Permit under the California Endangered Species Act is unclear, since that application relied on the proposed operations in the Draft Biological Assessment.

Much of the testimony for the WaterFix Change Petition assumed the proposed operations in the Draft Biological Assessment. The Department of Water Resources and the U.S. Bureau of Reclamation had indicated in the WaterFix Change Petition hearing that the “H3+” operations scenario analyzed in the Biological Assessment was going to be close to the approved operations.

Many WaterFix actions need further analysis

This is from the cover letter by the US. FWS:

The following activities requiring future Federal approvals and therefore addressed programmatically are:

(1) construction of the NDD and associated structures;

(2) construction of the HORG;

(3) construction of the CCWD settlement agreement facilities;

(4) operations of new and existing CVP and SWP water facilities under dual conveyance;

(5) future maintenance;

(5) future monitoring; [duplicate number in letter]

(6) compensatory mitigation associated with construction of the NDD, HORG, and CCWD settlement agreement facilities; and

(7) the CWF Adaptive Management Program.


In order to ensure that future actions developed for the CWF are consistent with this analysis, Reclamation and DWR have proposed a framework consisting of Guiding Principles that are analyzed as part of this BiOp. One or more subsequent consultations will be needed to address activities associated with future approvals. No Incidental Take Statement is included for activities addressed programmatically because those subsequent consultations will address incidental take associated with those activities.

Construction related permits issued

The cover letter lists activities that were fully analyzed for the Biological Opinion. They are entirely construction related.

The following activities analyzed as a standard consultation are:

(1) construction of the tunnels;

(2) expansions and other modifications of Clifton Court Forebay;

(3) associated infrastructure;

(4) geotechnical explorations,

(5) compensatory mitigation associated with construction except the North Delta Diversions (NDD), Head of Old River Gate (HORG), and Contra Costa Water District (CCWD) settlement agreement facilities; and

(6) specific construction-related conservation measures including preconstruction surveys for listed terrestrial species.

The reasons for the change to a programmatic opinion for the long term operations of the WaterFix project unclear, but the change allows the Bureau of Reclamation significant latitude to change the proposed operations that were analyzed in the Draft Biological Opinion, and that were worked out with the U.S. Fish and Wildlife Service and National Marine Fisheries Service under the Obama administration.


Posted by: Deirdre Des Jardins | May 7, 2017

Full San Luis Endangers 200,000 people — more coverage

Alex Breitler of the Stockton Record published the results on his inquiry into safety issues with San Joaquin Valley dams:  The state of our dams.

In the article, Deirdre Des Jardins of California Water Research points out that people’s lives are being endangered by filling the seismically challenged San Luis reservoir.   The 2 million acre foot reservoir needs a restriction of at least 50 feet to be safe in a large earthquake.

Breitler quotes the Bureau of Reclamation as saying that a reservoir restriction at San Luis would “be a massive issue for water users.”   Presumably this includes the very, very, VERY sorry Department of Water Resources that has been publicly apologizing to Oroville residents.   The Bureau declined to disclose the probability of a large earthquake in the area.


San Luis Reservoir

Posted by: Deirdre Des Jardins | April 22, 2017

Scientific integrity in DWR’s engineering: sea level rise

The WaterFix tunnel design assumes 18 inches of sea level rise by Late Long Term (2065.)  All structures, including tunnel intakes, tunnel shafts, the Intermediate Forebay, and the new parts of Clifton Court Forebay are being designed to withstand sea level rise of 18 inches. Simulated operations also consider salinity intrusion with a maximum of 18 inches of sea level rise.   Simulations by the U.S. Army Corps of Engineers show severe salinity intrusion with 1.68 meters (5.5 feet) of sea level rise, which could be reached by the end of this century.

Max salinity intrusion with 1.68 m sea level rise                U.S. Army Corps of Engineers

The Department of Water Resources’ assumptions about sea level rise date back to 2009. By 2013, when the first BDCP Draft Environmental Impact Report / Enviromental Impact Statement (EIR/EIS) came out, it was clear that the sea level rise estimates were obsolete. But the Department of Water Resources was reluctant to analyze higher values of sea level rise, stating in the Draft EIR/EIS that “the modeling analysis for BDCP had been designed and performed.” (Chapter 29, p. 13.)  Doing a new analysis would also have been quite expensive.

In a 2014 review, the Delta Independent Science Board was harshly critical:

The potential effects of climate change and sea-level rise are underestimated. . . . The potential direct effects of climate change and sea-level rise on the effectiveness of actions, including operations involving new water conveyance facilities, are not adequately considered. . . . We believe this is dangerously unrealistic.

DWR responded to the Delta ISB’s review, stating that “the scope of an EIR/EIS is to consider the effects of the project on the environment, and not the environment on the project.”

What could go wrong?

Jones Tract Flood 2004

Jones Tract Flood, 2004.      Source:  CA Water Blog

 The graph below shows projections of sea level rise by the U.S. Army Corps of Engineers and NOAA Climate Change Center, compared with the WaterFix tunnel design estimate of 18 inches, and the maximum operating range of 33 inches proposed under the new Delta plan amendments.  Under the high rate of sea level rise, the maximum operating range is exceeded around 2060-2070.

SLR w tunnels2

Sea level rise at Golden Gate — U.S. Army Corps and NOAA

Changing the sea level rise requirements in the Delta Reform Act

The Delta Reform Act required that the WaterFix EIR/EIS have a
comprehensive analysis of operations under sea level rise of up to 55 inches. (Section 85032(b)(2).)

The Delta Stewardship Council is proposing to amend the Delta Plan to only require that the EIR/EIS consider sea level rise of 20 inches at 2070, and the operations with up to 33 inches of by 2100.    These are derived from mean projections from the now obsolete 2012 report by the National Research Council.

The Department of Water Resources quietly disclosed the risks of underestimating sea level rise in a new paragraph in an unrelated chapter of the Final EIR/EIS:

• Underestimating sea level rise in the project design will result in harmful realized impacts such as flooding. Harmful impacts are more likely to occur if the project design is based upon a low projection of sea level rise and less likely if higher estimates of sea level rise are used. In situations with high consequences (high impacts and/or low adaptive capacity), using a low sea level rise value involves a higher degree of risk. (Examples of harmful impacts that might result from underestimating sea level rise include damage to infrastructure, contamination of water supplies due to saltwater intrusion, and inundation of marsh restoration projects located too low relative to the tides). (Chapter 9, section

The Ocean Protection Council’s Science Advisory Team Working Group just released a new risk report for sea level rise.    The highest sea level rise is projected for the highest greenhouse gas emissions.   For the current climate change models, possible scenarios are called “Representative Concentration Pathways.”   The highest Representative Concentration Pathway is RCP 8.5.    For the RCP 8.5 scenario, there is a 28% chance that sea level rise at the Golden Gate will exceed 3 feet by 2100, and an 8% chance it will exceed 4 feet.   Thus DWR’s use of sea level rise estimates of 18 inches for the WaterFix tunnels could result in a useful lifetime of less than 50 years for the project.

Sea level rise exceedance at the Golden Gate under highest GHG concentration pathway (RCP 8.5)

There is still significant uncertainty about catastrophic effects of climate change.    But these graphs show that using unrealistic assumptions for the $17 billion WaterFix project could result in severe and unanalyzed impacts on the project.


Griggs, G, Árvai, J, Cayan, D, DeConto, R, Fox, J, Fricker, HA, Kopp, RE, Tebaldi, C, Whiteman, EA (California Ocean Protection Council Science Advisory Team Working Group). Rising Seas in California: An Update on Sea-Level Rise Science. California Ocean Science Trust. 2017. Available at

National Research Council, Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future. Washington, DC: The National Academies Press. 2012. Available at

Parris, A., P. Bromirski, V. Burkett, D. Cayan, M. Culver, J. Hall, R. Horton, K. Knuuti, R. Moss, J. Obeysekera, A. Sallenger. Global Sea Level Rise Scenarios for the US National Climate Assessment. 2012. Available at

Sweet, W.V., R.E. Kopp, C.P. Weaver, J. Obeysekera, R.M. Horton, E.R. Thieler and CZ. NOAA Technical Report NOS CO-OPS 083, Global and Regional Sea Level Rise Scenarios for the United States. 2017. Available at

U.S. Army Corps of Engineers, Sea Level Change Calculator. 2015. Available at

Delta Independent Science Board, Review of the Draft EIR/EIS for the Bay Delta Conservation Plan. 2014. Available at

Bay Delta Conservation Plan Public Draft EIR/EIS, Chapter 29 — Climate Change. 2013. Available at

WaterFix Final EIR/EIS, Volume IChapter 9 – Geology and Seismicity. 2016. Available at

California Water Research, Comments on Water Supply and Water Quality Modelling in the WaterFix RDEIR/SDEIS. 2015. Available at

Chris Clarke, New Sea Level Rise Study Calls Delta Tunnels Into Doubt, KCET. April 2016. Available at

Posted by: Deirdre Des Jardins | April 21, 2017

San Luis Dam seismic upgrade to cost $600-700 million

031217_2104_FullSanLuis1.jpgValley Public Radio ran a segment on San Luis Reservoir endangering 200,000 people in the San Joaquin Valley on Tuesday, April 18.  Ezra David Romero interviews Deirdre Des Jardins of California Water Research and Ron Stork of Friends of the River as well as the Bureau of Reclamation’s Dam Safety Office. The Bureau spokesperson said the seismic remediation and raise of San Luis Dam is estimated to cost $600-700 million.

Valley Edition: April 18

Together with the Oroville spillway repair, costing at least $275 million, there is now an estimated total of almost $1 billion for public safety upgrades to Oroville dam and San Luis dam. And it’s not just the State Water Project’s two huge dams. The original State Water Project power plant and pumping plant equipment is also near the end of its estimated useful lifetime.

Table of SWP facility lifetimes.    2016 SWRDS financial statement

hyatt turbine

Hyatt Turbine Replacement 

There are real questions about whether the Department of Water Resources has budgeted for needed upgrades of its aging facilities. California Water Research dug up DWR’s projected capital and operating costs for the original State Water Project facilities and produced some graphs.

The original State Water Project facilities include the Upper Feather, Oroville, Delta, and Suisun Marsh facilities, as well as San Luis Dam and the California Aqueduct to Dos Amigos.   The projected capital costs for these facilities are so low that it appears that the cost projections assume no major repairs. What about operating costs? Those are also projected to grow more slowly than the 2.75% rate of inflation.

Annual capital costs for last 30 years from Bulletin 132-16, Table B-13

Projected capital costs from Bulletin 132-16, Table B-13

Projected Operating Costs from Bulletin 132-16, Table B-13

Posted by: Deirdre Des Jardins | April 9, 2017

Spillway failure is third serious incident at Oroville-Thermalito complex

The failure of the lower part of the Oroville main spillway is the third serious incident at the Oroville-Thermalito complex. The causes of the incidents were all related to conditions previously noticed as safety violations by the Federal Energy Regulatory Commission’s Division of Dam Safety and Inspections.   The three incidents indicate serious maintenance issues at the Oroville facilities.

In 2007, a site inspection by John Onderdonk, chief of FERC’s San Francisco Regional Office of Dam Safety and Inspections, found three safety violations related to the later incidents. These were the items in Onderdonk’s letter to DWR:


  1. The bolts and nuts that secure the river valves to the pipe flanges were observed to be rusty. This item was also on the 2006 follow-up letter and your plan and schedule calls for the repair to be finished by November 2, 2007. […]

8. Small areas of spalling damage of the concrete on the floor of the spillway were noted during the inspection. By December 3, 2007, please provide a plan and schedule to repair areas on the spillway where the concrete has been damaged.

9. During the inspection, Mr. Onderdonk inquired when the last time that the spillway drainage system has been cleaned out and he was informed that it has been many years. There are a series of vertical clean outs located on each side of the service spillway. By December 3, 2007, please provide a plan and schedule to clean out the spillway drains.


  1. A five-gallon container of oil was found on the floor in the powerplant. By December 3, 2007, please provide a plan and schedule to remove the oil container or provide secondary containment for the container.  […]

These safety violations presaged 3 serious incidents:

  1. In 2010, five workers were injured in the river tunnels when a 6′ tall, 10′ wide steel panel with rusted bolts flew off during a test.
  2. In 2012, a fire destroyed the Thermalito Power Plant, caused by a relay short-circuit and an unknown source of fuel.
  3. In 2017, the main spillway developed a large crater.

Details of Incidents

  1. Rusty bolts in river tunnels

In July 2009, during a test of the river tunnels, a large steel panel flew off during a test in the river tunnels injuring five workers, one seriously.  As reported by Toni Scott in the Chico Enterprise-Record, the cause was corroded bolts:

Shortly after the valves were opened, a 6-foot-tall, 10-foot-wide steel panel near the employees collapsed, sending flying debris toward the workers and creating a vacuum-like force that pulled them toward a tunnel carrying water out of the dam.

The investigation also found that DWR failed to properly maintain the collapsed steel panel, finding that the bolts securing the non-structural panel to the wall were corroded and that the panel “was never inspected for integrity or safety for over 40 years.”

A foam sealant had been placed where the bolts had corroded, “indicat(ing) knowledge of corrosion and failure of the bolts and the seal of the door,” the report reads.

2. Five gallon container of oil on floor of powerplant

In 2012, the Thermalito Pumping Plant has a major fire. According to a presentation by DWR’s staff to an engineering conference, the fire cost an estimated $90 million in cleanup and $75 million in repairs.


The results of the forensic investigation of the cause of the fire were reported in The investigation determined that a short-circuit in a relay was responsible, but lab controlled experiments were unable to recreate the ignition. The relay engineers said there were two possible additional causes:

  • An unknown source of fuel was available that could be and was ignited; and
  • The actual circuit No. 19 fault produced far more thermal energy than was generated during testing.

Forensic expert Mark Schafer, of Electro-Mechanical Recertifiers, also identified other contributing factors, including: aged cables, mixed voltages and over-stacked cables in the cable trays, a lack of fire stops between elevations, an inoperable dry chemical fire extinguisher cart, and combustible materials such as plant schematics and additional historical items printed on large paper sheets stored within the plant.

Two months before the fire, Mark Cowin, the Director of the Department of Water Resources had told the Metropolitan Water District Board that DWR no longer had the appropriate financial resources to operate and maintain the aging SWP facilities.

According to the State Water Project financial statements, the life of the equipment in the State Water Project power plants and pumping plants is 30-50 years.  The Thermalito pumping plant will be 50 years old in 2019.

lifetime table

3. Spalling damage to spillway chute and drains not cleaned out

FERC’s San Francisco office of Dam Safety and Inspections had to remind the Department of Water Resources in August 2008 that the repairs for the main spillway chute were needed.

An investigation by DWR in 2008 of the main spillway chute showed that the concrete surface had more extensive damage than just the “small areas of spalling” noticed by John Onderdonk in 2007.  The bid summary in 2009 shows that the main spillway chute needed 10,000 linear feet of sawcutting one inch deep, and 83 cubic yards of void repair. The chute also needed 3,900 linear feet of major crack repair, as well as 23,700 linear feet of contraction joint repair.

Although the letter from FERC requested Department of Water Resources to submit a followup report on the main spillway chute repair, California Water Research could not locate any report about the repair in DWR’s public FERC filings.  As previously reported by California Water Research, the Bureau of Reclamation’s Guide to Concrete Repair recommends investigation of the causes of cracks in concrete hydraulic structures.

This post was updated on April 10, 2015 to include information about the expected lifetime of facilities.

The Federal Emergency Management Agency (FEMA) defines High Hazard dams as “those [dams] where failure or mis-operation will probably cause loss of human life.” The current industry standard is to have Emergency Action Plans for all High Hazard dams, but California does not give the Division of Safety of Dams the authority to require dam owners to prepare one.

According to a report from FEMA’s National Dam Safety Program, only ten states do not give their dam safety agencies the authority to require Emergency Action Plans: Alabama, California, Georgia, Idaho, Indiana, Iowa, Kentucky, North Carolina, Vermont, and Wyoming.  The map below, from the FEMA report, shows those states in gray.

The map also shows the percentage of high hazard dams that had Emergency Action Plans. In 2013, only 45% of High Hazard dams in California had Emergency Action Plans. California has some of the largest dams in the country, and major earthquake risks.

1 Percentage of State-regulated High Hazard dams with Emergency Action Plans         Source: FEMA


Federal Emergency Management Agency, “Federal Guidelines for Dam Safety: Hazard Potential Classification System for Dams,” April 2004.   Available at

Federal Emergency Management Agency, “Dam Safety in the United States:  A Progress Report on the National Dam Safety Program,” August 2014.  Available at

U.S. Army Corps of Engineers, “National Inventory of Dams database.”  Available at

The California Department of Water Resources owns three smaller dams upstream of Oroville, including two on tributaries of the Middle Fork of the Feather River, and one on a tributary of the North Fork of the Feather River.  Records show that all three upstream dams had extensive spillway repairs in 2009, at the same time that the Oroville main spillway had extensive repairs.  The repairs for all three spillways included sawcutting concrete, void repairs, and repairs of major cracks. Frenchman Dam also had repairs of the spillway lip. Records show the three dams were last inspected in October of 2014.

Two of the dams, Grizzly Valley and Frenchman, began spilling last week, according to news reports. There are a number of small communities on tributaries and the Middle Fork of the Feather River that could be inundated if the dams had major spillway erosion. The U.S. Army Corps’ National Inventory of Dams Database shows no Emergency Action Plan for any of the dams, although all appear to meet the definition of High Hazard dams, because failure could result in loss of life. The State of California does not require Emergency Action Plans for High Hazard dams, and the dams are not supervised by the Federal Energy Regulatory Commission.

Frenchman Dam, at the headwaters of the Middle Fork of the Feather River, is on Little Last Chance Creek. Little Last Chance Creek flows down past the small community of Chilcoot-Vinton (population 457) into the Sierra Valley, where it joins with other tributaries to form the beginning of the Middle Fork of the Feather River. Frenchman Dam is 139 feet tall and impounds Frenchman Lake, up to 55,477 acre-feet of water.

1 Frenchman Lake and Lake Davis                                 Source: Google Earth

Further downstream, just north of the City of Portola (population 2,100), Big Grizzly Creek joins the Middle Fork of the Feather River. Grizzly Valley Dam, on Big Grizzly Creek, is 115 feet tall and impounds Lake Davis, up to 83,000 acre-feet of Water. Numerous other communities are on the Middle Fork of the Feather River downstream of the City of Portola including Deleker, population 700, Mabie, population 161, Iron Horse, population 297, Graeagle, population 737, and Cromberg, population 261.

2 City of Portola, California

DWR’s third dam is Antelope Dam, on Indian Creek, a tributary of the North Fork of the Feather River, in Plumas National Forest. Antelope is 113 feet tall and holds 22,566 acre-feet of water. The small community of Taylorsville (population 150) is on Indian Creek below Antelope Dam.

3 Antelope Lake                              Source: Google Earth

Grizzly Valley Dam, which impounds Lake Davis, began spilling last week, as did Frenchman.

On September 14, 2009, the Department of Water Resources published a notice soliciting bids  for repairs of the concrete chute on the main Oroville spillway , as well as for repairs of the spillway chutes of Grizzly Valley, Frenchman, and Antelope Dams.  DWR also published a summary of received bids, which showed that the Antelope Dam spillway had 1,790 linear feet of sawcutting and 47 cubic feet of void repair, as well as 100 linear feet of major crack repair and 200 linear feet of subdrain repair. The Frenchman Dam spillway had 713 linear feet of sawcutting and 100 linear feet of major crack repair. Grizzly Valley Dam had 40 linear feet of sawcutting and 40 linear feet of major crack repair.

Posted by: Deirdre Des Jardins | March 18, 2017

Risk study: $21.8 billion in property in Oroville inundation path

Risk Management Solutions, a leading catastrophic risk modeling company headquartered in Silicon Valley, did a “what if?” modeling of a breach of the Oroville Dam. Risk Management Solutions estimated there is $21.8 billion in damageable property in the Oroville Dam inundation path. See RMS, What If The Oroville Dam Had Collapsed Completely? March 3, 2017.

Dam inundation is not covered by standard insurance policies. Only NFIP flood insurance covers flooding. But only buildings in 100 year flood plains are required to have flood insurance – and not even those buildings if they are behind FEMA certified levees. Risk Management Solutions compared the FEMA 100 year flood zones with the Oroville Dam inundation path, and found that areas with no flood insurance would include most cities: Biggs, Gridley, Live Oak, Oroville, South Oroville, Thermalito, and Yuba City.

There are similar issues with the San Luis Dam inundation path – and also billions of dollars of property at risk, with no insurance that would cover flooding from dam failure. Both Oroville Dam and San Luis Dam are known to have seismic issues – San Luis Dam has a Bureau of Reclamation initiated formal Corrective Action Study, and Oroville Dam has a mandate by the FERC five year Independent Consultant dam safety review to do a seismic re-evaluation. (See the Matt Weiser, Oroville Dam earthquake investigation may be needed, Sacramento Bee, November 29 2013.)

Failure of Oroville and San Luis Dams is not only an enormous economic risk for the Sacramento and San Joaquin Valleys, it is also an enormous risk for the California budget. Under the 1999 Paterno decision, the state of California could be liable for inverse condemnation if courts later found that the Department of Water Resource’s operations or maintenance of these large dams exposed people and property to unreasonable risk. The Paterno decision states:

“The condemnation clause of the California Constitution provides in part that ‘Private property may be taken or damaged for public use only [citation omitted] when just compensation, ascertained by a jury unless waived, has first been paid to, or into court for, the owner.’ (Cal. Const., art. I, § 19.) Where the government damages property without first paying for the right to do so, the owner may sue for inverse condemnation. [citations omitted.]”

“….the only way to determine whether a damaged private landowner has thereby been forced to contribute a compensable “disproportionate” share of the public undertaking is to determine whether the system, as designed, constructed, operated, and maintained, exposed him to an ‘unreasonable’ risk of harm, either individually or in relation to other landowners.’ ” [citations omitted.]”

It seems clear that it is in the best interests of both the public and the state of California that the seismic and structural issues with these 1960s era dams be carefully considered and adequately remediated, both in the interim and with long term solutions.

1 FEMA 100 year flood plains                                                                                       Source: RMS

2 Oroville inundation area                                                                                                  Source: RMS

Posted by: Deirdre Des Jardins | March 14, 2017

DWR’s unpublished studies of the Oroville emergency spillway

As explained below, laws governing the formal dam safety reviews by the Federal Energy Regulatory Commission required an assessment of the adequacy of Oroville Dam’s emergency spillway.   The safety reviews relied on two unpublished studies by the Department of Water Resources’ Division of Engineering.

As part of formal reviews in 2004 and 2009, DWR’s Division of Engineering performed studies of the impacts of erosion below the Oroville emergency spillway weir. The first study appears to have been only distributed internally.  A published agenda shows the second study was presented for 15 minutes to the Federal Energy Regulatory Commission’s dam safety review team, and was marked, “CEII,” or Critical Energy Infrastructure Information, as part of FERC’s standard practice. Although stakeholders could request the second study through FERC’s FOIA process, they would have had to (1) know about the second study, and (2) sign a nondisclosure agreement to get it.

The distribution of DWR’s 2004 and 2009 Oroville emergency spillway studies is reminiscent of the notice of demolishment of Arthur Dent’s house in Hitchhiker’s Guide to the Galaxy:

But the plans were on display…”

“On display? I eventually had to go down to the cellar to find them.”

“That’s the display department.”

“With a flashlight.”

“Ah, well, the lights had probably gone.”

“So had the stairs.”

“But look, you found the notice, didn’t you?”

“Yes,” said Arthur, “yes I did. It was on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying ‘Beware of the Leopard.”

This is apparently standard for information used in FERC’s dam safety reviews.

The Federal Energy Regulatory Commission (FERC) Dam Safety Review Process

FERC is governed by the Federal Power Act. Part 12D requires a formal review of the safety of dams every five years by a panel of independent consultants.   One of the most important aspects of the Part 12D reviews is the Potential Failure Mode Analysis, or PFMA. The FERC Dam Safety Program webpage describes a PFMA as follows:

A PFMA is an informal identification and examination of “potential” failure modes for an existing dam by a team of persons. It is based on a review of all existing data and information, first hand input from field and operational personnel, site inspection, completed engineering analyses, identification of potential failure modes, failure causes and failure development and an understanding of the consequences of failure.

Section 12.35 of the FPA, Part 12D mandates that FERC’s PFMA include a review of spillways:

(b) Evaluation of spillway adequacy. The adequacy of any spillway must be evaluated by considering hazard potential which would result from failure of the project works during flood flows.

(1) If structural failure would present a hazard to human life or cause significant property damage, the independent consultant must evaluate the ability of project works to withstand the loading or overtopping which may occur from a flood up to the probable maximum flood or the capacity of spillways to prevent the reservoir from rising to an elevation that would endanger the project works.

Oroville’s engineering design includes using the emergency spillway for the probable maximum flood. So analyzing the performance of Oroville’s emergency spillway was required under Part 12D, section 12.35.

Seventh Independent Consultant’s Safety Review in 2004

FERC’s e-library records show that in 2004, FERC oversaw the Seventh Independent Consultant’s review of the safety of Oroville and Thermalito dams. FERC records show the report of the Seventh Independent Consultant recommended that an erosion study of the hillside below Oroville emergency spillway be done, because a consultant thought that sediment could cause failure of the downstream dam. Based on this recommendation, FERC’s Division of Dam Safety & Inspections requested that DWR do an erosion study of the hillside. The Department of Water Resources formally responded in 2006:

Our Division of Engineering’s Project Geology Section has reviewed the erodibility of the emergency spillway’s downstream area. There is only one to four feet of erodible top soil in the downstream area and erosion would not compromise the stability of the emergency spillway. The amount of material eroded is dependent on the volume and duration of a spill, but material transport in the Feather River is expected. Therefore, we will re-evaluate the Thermalito Diversion Dam stability analysis to account for additional lateral earth pressures on the concrete structure due to material deposited upstream of the dam prior to the Project No. 2100 Eighth Part 12D Independent Consultant Board of Safety Review in 2008…

Original Spillway plans show no boreholes on hillside below spillway

It is unclear what geotechnical data DWR’s Division of Engineering was using to analyze the erodibility of the hillside below the emergency spillway. The original plans, published in 1974 in DWR’s Bulletin 200, Volume III, p.94, show no boreholes on the hillside below the emergency spillway weir – only under the concrete weir. It is unclear if DWR did further geotechnical investigation.

A pdf with full size graphics from Bulletin 200 is posted here: Design and General Plan of Oroville Spillway.

Eighth Independent Consultant’s Safety Review in 2009

In 2009, for FERC’s Eighth Part 12D Independent Consultants’ review, DWR chose two engineers from GEI consulting, Bill Rettberg, then Vice President of GEI, and Steven Verigin, Chief Geotechnical Engineer. A GEI document on the Oroville/Thermalito safety review states that Rettberg and Verigin worked “very closely” with DWR on “clarifying and reclassifying” some of the Potential Failure Modes (PFMs) of the dams.

The team worked very closely with DWR throughout the process, working on a shortened schedule to comply with the FERC deadline. The PFMA audit session was an intense one-day activity, that the Board and the DWR/FERC/and DSOD believed was valuable to revisiting the original PFMs and clarifying and reclassifying some of the PFMs.

The agenda for the “intense one-day” PMFA audit session shows that Tim Wehling of DWR’s Division of Engineering spent 15 minutes presenting a study of the emergency spillway to the review team.

1515-1530    Study Results; Oroville Emergency Spillway  Wehling (DOE)

The Eighth Part 12D Independent Consultants’ report is not publicly available. It is also classified “CE II” – i.e., Critical Energy Infrastructure Information.  However, subsequent FERC correspondence shows no mention of erosion of the emergency spillway as a Potential Failure Mode (PFM) for Oroville Dam or Thermalito Diversion Dam.

DWR’s Division of Safety of Dams also formally reviews the safety of Oroville and Thermalito dams at least every five years. However, in practice, DSOD’s  five year review of DWR’s dams relies on the FERC five year review. Subsequent documentation of potential failure modes of Oroville by DSOD does not show erosion of the emergency spillway as a Potential Failure Mode.

Oroville’s spillway failure appears, in hindsight, to have relied on inadequate analysis of the emergency spillway as a Potential Failure Mode.  This raises real questions about DWR’s 2004 and 2009 engineering analyses.   It is currently unclear if these analyses will ever be publicly released by DWR.

This post was updated on March 16, 2017 to correct the definition of CEII classification and provide a link.


Posted by: Deirdre Des Jardins | March 12, 2017

Full San Luis Dam endangers over 200,000 people

San Luis Dam, also known as B.F. Sisk Dam, is 382 feet tall and 18,600 feet long, and impounds up to 2 million acre-feet of water. It is the largest offstream dam in the United States.  Pursuant to the 1960 San Luis Act, San Luis Dam was constructed by the Bureau of Reclamation, and is still owned by the Bureau. The Bureau of Reclamation and the California Department of Water Resources entered into a Joint Use Agreement for San Luis in December 1961, which provides that the State of California operates and maintains the San Luis facilities. Because the dam is owned by the Bureau of Reclamation, it is not subject to oversight by DWR’s Division of Safety of Dams, or the Federal Energy Regulatory Commission’s Division of Dam Safety and Inspections.


1 San Luis Dam and Reservoir                                                                         Source: Bureau of Reclamation

San Luis Dam is in a very seismically active area, and parts of the Ortigalita fault run through the reservoir. In the 2000’s, it was recognized that the Ortigalita fault could generate an earthquake of magnitude 7.1. The dam is also only 28 miles from the San Andreas Fault, and 23 miles from the Calaveras-Hayward Fault.

San Luis seismic sources

2 Faults near San Luis Dam Source: California Department of Conservation, 2012

It has been known since a large slide in 1981 that the earthen dam has serious structural and seismic deficiencies. The dam is currently the subject of a formal Bureau of Reclamation Corrective Action Study, begun in 2007. San Luis Dam is known to need an operating restriction of at least 50 feet to be within Reclamation’s Dam Safety Public Protection Guidelines. However, because the dam is operated by the California Department of Water Resources, there appears to have been no formal consideration of an interim operating restriction to protect lives and property.

1981 Embankment Slide

In September 1981, a 1,100 foot section of the upstream San Luis Dam embankment near the crest of the dam — 400,000 cubic yards — slid 177 feet. It was a deep seated failure which extended through the fill and into the native soil under the dam.

3 September 1981, San Luis Dam Embankment slide                                                           Source: J. Michael Duncan

1999 engineering analysis by the nationally recognized civil engineer  J. Michael Duncan showed that the factor of safety for the dam had been reduced from 4.0 to 1.21 – too low to be safe in an earthquake. The table below is from Duncan’s analysis.

4 Safety factors after repair                Source: Duncan, The use of back analysis to reduce slope failure risk (1999)

Known Seismic Hazards

Beginning in 1982, geologist Larry Anderson at the Bureau of Reclamation conducted a series of seismic studies which showed that the Ortigalita fault has higher rates of activity than had been previously recognized. The independently reviewed studies also showed that a large earthquake could lead to crest settlement and overtopping of the dam, which would result in large uncontrolled releases and likely dam failure. The Mid-Pacific Regional Office of the Bureau initiated a formal Corrective Action Study in 2007. In the letter to CVP contractors, the Mid-Pacific Regional Office stated:

Through the Dam Safety Program, Reclamation has identified several conditions at B.F. Sisk Dam that require action to reduce risks.

• The dam is located in a seismically active area, very close to the Ortigalita Fault

• Studies and deformation analyses conducted during 2005 indicate that, during a major earthquake, crest settlement greater than freeboard, or cracking associated with embankment deformation, could occur and lead to dam failure

• Failure of the dam could inundate hundreds of square miles including the town of Santa Nella, about 7 miles of Interstate 5, and numerous farms and houses along the San Joaquin River including some areas of Stockton

• An independent consultant review board agreed with Reclamation that the calculated crest settlement is possible for the estimated peak ground accelerations associated with the Ortigalita Fault

Under the current schedule, the Mid-Pacific Regional Office’s Corrective Action Study is not expected to be completed until May of this year. Construction on the proposed corrective action is not expected to begin until at least 2020, and funding has not yet been identified. The Mid-Pacific Regional Office published a draft appraisal for the San Luis Dam Corrective Action in 2013. The study indicated that a reservoir restriction of at least 50 feet is required to bring the seismic risk to within current Reclamation Public Protection Guidelines:

Since B.F. Sisk is an off-stream storage facility, a reservoir restriction is feasibly obtained by not filling (pumping into) the reservoir. This measure would consist only of a change in operations, so it is considered non-structural.

Based on current seismic deformation estimates (Reclamation 2013b) it appears that a permanent restriction of at least 50 feet would be required to reduce the risk to within current Reclamation Public Protection Guidelines. (emphasis added, p. 27)

However, Mid-Pacific Regional Office documents show no consideration of interim operating restriction on the dam, although such a restriction would normally have been considered under the Bureau’s 2011 Interim Dam Safety Public Protection Guidelines. The diagram of first priority risk reduction actions, from p. 30 of the 2011 Public Protection Guidelines, is shown below. The first priority actions clearly include taking interim steps for risk reduction.

Dam safety risk management actions             Source: Reclamation Public Protection Guidelines

Because of California’s torrential rains this winter, San Luis reservoir filled. Failure to formally consider and implement an operating restriction has resulted in catastrophic risks, both to lives and to California’s water supply. If an earthquake were to occur, the earthen dam could slump and be overtopped. Failure of the dam would create an enormous path destruction, almost 10 miles wide and over 80 miles long, from Los Banos to Antioch in the western Delta. The inundation would immediately hit Santa Nella (population 1,400) and Los Banos (population 37,000). It would flow through western Merced and Stanislaus counties, impacting West Modesto (population 5,600.) In San Joaquin County, the inundation would impact the western part of Manteca (population 72,000), the western part of Stockton (population 298,000.) In Contra Costa County, the inundation would impact Discovery Bay (population 14,000), and Brentwood (population 55,000.) In 2003, the San Joaquin County Office of Emergency Services estimated that 165,000 people were in the inundation path.

6San Luis Dam Inundation Map                                                                               Source: City of Ripon

The dam inundation path also includes Clifton Court Forebay and the State Water Project and Central Valley Project Banks and Jones pumping plants. Potential impacts on Clifton Court Forebay and the SWP and CVP facilities is unknown. However, failure of San Luis dam would have catastrophic impacts on State Water Project and Central Valley Project water supplies.

7 State Water Project Banks Pumping Plant                                          Source: The California Spigot

Although an operating restriction on San Luis reservoir would have a significant impact on State Water Project and Central Valley Project water supplies, most of the largest SWP and CVP contractors do have other storage available that does not have catastrophic risks to lives, property, and infrastructure. Metropolitan Water District has Diamond Valley Reservoir, with a capacity of 800,000 acre feet, as well as groundwater storage in the Semitropic groundwater bank.  Santa Clara Valley Water District also has groundwater storage in Semitropic. Kern County Water Agency has groundwater storage available in the Kern Water Bank and other groundwater banks.

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