Posted by: Deirdre Des Jardins | September 9, 2019

Delta tunnel – commitment to updated science on sea level rise

On August 28, 2019, the Sacramento Press Club held a panel on Droughts, Tunnels & Clean Water: A Conversation on California Water Policy .  Panelists included  Secretary of Natural Resources Wade Crowfoot, MWD general manager Jeff Kightlinger, and the State water Contractors general manager Jennifer Pierre.

The transcript of the panel is now up on Maven’s Notebook.  Deirdre Des Jardins’ question is recorded:

I had a question about the Delta tunnel and sea level rise.  The last analysis that the North Delta intakes would stay fresh was done in 2010, which accounted for 55 inches of sea level rise and assumed no failure of the Delta levees.  My question for Mr. Kightlinger and Ms. Pierre is, are you going to do a new analysis for 10 feet of sea level rise?

The response by Jeff Kightlinger was explored in last week’s blog.   MWD is considering the cost-benefit tradeoffs of moving the Delta tunnel intakes north.

Secretary Crowfoot’s response is equally important:

I would add that’s the benefit of the new environmental review is to bring in updated scienceI think its scary for anybody who watches how these projections about sea level rise are changing, the acceleration of ice melt in the arctic so this new CEQA analysis will build in, as I understand, with the updated science as it relates to sea level rise.”

The Newsom administration’s expressed commitment to using updated science on sea level rise for the new CEQA analysis is long needed.  In 2014, a prescient review by the Delta Independent Science Board stated:

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. […] Similar comments could be made about the treatments of other disrupting factors, such as floods, levee failures, earthquakes, or invasive species, any of which could profoundly alter the desired outcomes of BDCP actions.

In their response to our preliminary draft review, the Department of Water Resources noted 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”. If the effects of major environmental disruptions such as climate change, sea-level rise, levee breaches, floods, and the like are not considered, however, one must assume that the actions will have the stated outcomes. We believe this is dangerously unrealistic. 

(underlining added.)

In 2018, the Delta Stewardship Council’s Draft Staff Determination on WaterFix Consistency Appeal stated:

… the Department stated its assumptions still reflect the use of best available science because they are consistent with the recommended estimates for the sea-level rise under the “likely range” reported for years 2030 and 2060 in the latest guidance from the California Ocean Protection Council for sea-level rise planning.The California Ocean Protection Council, however, recommends the “likely range” for use in low risk aversion decisions, such as a coastal unpaved trail. (Ocean Protection Council, 2018 Update, p. 25.) Whereas, it recommends use of the H++ scenario, which is extreme risk aversion, for projects with a lifespan beyond 2050. (Ibid.)

The H++ scenario, from the 4th National Climate Change Assessment, projects up to 6.6 feet of sea level rise at the Golden Gate by 2080, and up to 10.2 feet of sea level rise at the Golden Gate by 2100.  These dates would be about 40-60 years after any Delta tunnel project was finished.

While the H++ scenario is a maximum estimate, it is important to use conservative design assumptions for sea level rise in the engineering design.  The rate of mass loss in the West Antarctic ice sheet has tripled in recent years.

800px-glacier_on_antarctic_coast_mountain_behind

Posted by: Deirdre Des Jardins | September 2, 2019

Delta tunnel:  MWD weighs moving intakes 20-30 miles north for sea level rise

On Wednesday, August 28, 2019, the Sacramento Press Club hosted a panel discussion, “Droughts, tunnels & clean water.”  The panel included Wade Crowfoot, Secretary of Natural Resources, Jeffrey Kightlinger, general manager and CEO of Metropolitan Water District, and Jennifer Pierre, general manager of the State Water Contractors. Stuart Leavenworth from the LA Times moderated the panel.

The Newsom administration has committed to modernizing Delta Conveyance to protect water supplies from earthquakes and sea level rise. In a July 8 update to the Metropolitan Water District’s Water Planning and Stewardship Committee, Crowfoot stated, “if you are a state agency and you are building infrastructure that you want to exist and be operating in 2100, you need to plan for between 5 and 10 feet of sea level rise.”  Crowfoot emphasized that sea level rise was one of the reasons the Newsom administration supported the Delta tunnel, stating, “when we’re talking about really protecting our water supply against sea level rise and saltwater intrusion, the underground conveyance or the tunnel becomes quite important.

The Newsom administration has relied on assertions by the Department of Water Resources that the North Delta is 15 feet above sea level.  But as explained in California Water Research’s August 12 blog post, this assertion is misleading.  In the North Delta, only the top of the Sacramento River levee is 15 feet above sea level.  Elevations at Courtland and Hood range from -1 to 8 feet above sea level, and the bottom of the Sacramento River is over 20 feet below sea level. California Water Research has recommended that new modeling be done of the performance of the North Delta intakes with high sea level rise.

During the Q&A period at the Sacramento Press Club luncheon,Deirdre Des Jardins advised the attendees of these facts. She asked Kightlinger and Pierre if they would commit to modeling the performance of the North Delta intakes with 10 feet of sea level rise and widespread levee failure. In response, Kightlinger stated that MWD is looking at moving the Delta tunnel intakes 20-30 miles north to accommodate sea level rise. Kightlinger stated that MWD is evaluating the increased costs of a longer tunnel, versus the benefits of extending the lifetime of the project.

It is unclear what intake locations Kightlinger was referring to.  But in 2010, the Department of Water Resources evaluated two sets of locations north of Freeport, which would resist salinity intrusion with 10+ feet of sea level rise.  The first set includes two locations on the west bank of the Sacramento River in South Sacramento, the second set, two locations upstream of the American River confluence.  A third set of alternative locations was downstream of the confluence with Steamboat Slough.  (see below.)  These would benefit salmon but have less resistance to salinity intrusion.
2010 intake locs

These alternative locations were considered and rejected in 2010, partly on the basis of modeling by Resource Management Associates (RMA) which was interpreted to show no impacts from salinity intrusion at any of the proposed intake locations.  But as explained in California Water Research’s August 6 blog, the 2010 RMA modeling is obsolete and has major limitations.  The 2010 RMA modeling assumed 55 inches of sea level rise, and no failure of North Delta levees.  The California Ocean Protection Council’s current estimate of maximal sea level rise by 2100 is 10 feet or 120 inches.  This is over twice the 2010 estimate.

As part of “assessment of efforts to modernize Delta Conveyance,” California Water Research has recommended that the Newsom administration document that the WaterFix intake locations need to be reassessed for performance with 10 feet of sea level rise and widespread levee failure.

Posted by: Deirdre Des Jardins | August 26, 2019

Delta Levees Investment Strategy: protecting Delta smelt?

The Delta Stewardship Council has considered and rejected an alternative for the Delta Levees Investment Strategy that prioritized reducing risks to lives and property in the Delta.  It’s listed as Alternative 3 in the Initial Statement of Reasons for the regulations adopting the strategy.

The Delta Stewardship Council explains that Alternative 3 was rejected because it would not prioritize levee investments that provide “ecosystem enhancements.”  This is from p. 23 of the Initial Statement of Reasons:

Alternative 3 – Prioritize Levee Investments in High Risk to Life or Property Areas

Alternative 3 focuses on prioritizing investments in levee improvements at islands or tracts identified as having a high risk to life or property, including urban and urbanizing areas of Sacramento, West Sacramento, and Stockton. Levee improvements that support other State interests (such as improving Delta ecosystem conditions or maintaining water supply corridors) would still occur but would be prioritized lower than investments in areas with high risk to life or property. Continued funding would be provided for maintenance of levees throughout the Delta where authorized by Water Code section 12980 et seq. and consistent with the recommendations of the CVFPB.

This alternative would not be less burdensome or equally or more effective than the proposed regulation. Alternative 3 was eliminated from consideration because although it would achieve or partially achieve many of the objectives of the proposed amendment, it would not prioritize levee investments that protect ecosystem enhancements that provide high benefits over other types of levee investments.

(underlining added)

But the rejection of Alternative 3 has more to do with the Delta Stewardship Council’s rejection of the initially proposed cost allocation method than with the need for ecosystem restoration projects in the Delta. The Separable Costs — Remaining Benefits (SCRB) cost allocation method was recommended by Arcadis and presented for the Delta Levees Investment Strategy peer review.

Under Separable Costs – Remaining Benefits, the extra costs to provide ecosystem benefits would have been assessed separately from protection of lives and property, and allocated separately.  Arcadis’ consultant, Dr. McMahon, stated:

In summary, the objectives are fairness primarily, so we’re trying to allocate only the costs incurred, so we want to allocate costs in proportions of benefits received; we don’t want any purpose to subsidize other purposes. There are four steps; the first step is the SCRB cost allocation by purpose and then that will inform the subsequent three steps listed here.”

In a previous blog post on the Delta Levees Investment Strategy, we explained that the McCormack-Williamson Tract and Dutch Slough restoration projects are part of the 8,000 acres of intertidal and subtidal habitat restoration required under the 2009 Biological Opinion.  The Tule Red restoration project on Grizzly Island is also part of the 8,000 acres of tidal habitat restoration.  Changes to levees are a relatively small part of these projects.
dutch slough EIR

The California EcoRestore web page lists several future habitat restoration projects on Sherman Island and Twitchell Island, both of which are designated as “very high priority.”  These include an $88.4 million setback levee on Twitchell Island, and restoration of 1,250 acres of wetland on the west end of the island. Funds have yet to be identified for an additional 3,900 acres of emergent wetland restoration on Sherman Island.  The EcoRestore program evolved from the CALFED Ecosystem Restoration Program.  The CALFED Ecosystem Restoration Program (ERP) was part of the CALFED Record of Decision.  The ERP proposed extensive habitat restoration for mitigation of exports by the State Water Project and Central Valley Project.

As explained in a previous blog post, the Delta Levees Investment Strategy regulations will mandate that these ecosystem restoration projects take priority over protecting communities in the primary Delta from flooding. With the new prioritization, the issue of cost allocation becomes more critical.

The Davis-Dolwig Act, passed in 1961, directed that Department of Water Resources include in its water charges an amount “sufficient to repay all costs incurred for the preservation of fish and wildlife” as a result of the project.  But, according to the Legislative Analyst’s Office, the Department of Water Resources has generally not followed Davis-Dolwig in determining charges to the State Water Contractors.

This post was updated on August 27 to include future EcoRestore projects on Sherman Island and Twitchell Island.

Posted by: Deirdre Des Jardins | August 20, 2019

Vanishing funds for levee upgrades for smaller, vulnerable Delta communities

The Delta Stewardship Council will be adopting regulations to implement the Delta Levees Investment Strategy (DLIS) on August 22, 2019.  Maps of the priorities for levee investments are available here.

The proposed regulations make investments in upgrading urban levees in West Sacramento and Stockton and adjacent areas “very high priority.” These investments are long needed, particularly for Stockton.  Stockton is the 7th largest city in California, and the levees are badly in need of improvement.

Funding for improvements to urban levees has typically been tied to federal projects and funded separately from improvements to levees in the primary zone of the Delta.  Improvements to the levees in the primary zone have been funded by the Delta Levees Subvention and Special Projects Programs, separate pots of money.

The Delta Levees Investment Strategy also prioritizes investments in improving levees protecting Bethel Island in the South Delta. The US Census estimated Bethel Island’s population at 2,379 in 2017.  This is also an important investment.

But Rio Vista, population 9,009, and Discovery Bay, population 15,525, are second priority for levee improvements.   And the Delta legacy towns of Clarksburg, Courtland, Locke, and the eastern bank of Walnut Grove are the lowest priority, even though Clarksburg and Courtland have public schools.  (Walnut Grove is on both sides of the Sacramento River.)

DLIS NDDelta Levee Investment Priorities — Closeup of North Delta

SouthDelta DLIS.pngDelta Levee Investment Priorities — Closeup of South Delta

The Central Delta Water Agency has commented that, given the shortage of funds for the Delta Levees Subvention and Special Projects Programs, no or almost no funds will be available for levee improvements for islands in the second tier, and none for the lowest tier.  Thus the Delta Levees Investment Strategy codifies the somewhat chilling calculus that protecting smaller, vulnerable Delta communities from flooding is not in the state interest.

One of the main reasons there are insufficient funds to protect smaller Delta communities is that the Delta Levees Investment Strategy also assumes that public funds must be spent to protect Delta exports and pay for mitigation of impacts of the State Water Project and Central Valley Project.

The Delta Levees Investment Strategy designates as “very high priority” upgrades to the Delta islands marked as “critical for Delta exports” in a 2010 PPIC report, Levee Decisions and Sustainability for the Sacramento-San Joaquin Delta.  One of these islands has the town of Isleton, but the rest are more sparsely inhabited.

Levee analysis.png

According to the proposed Delta Levees Investment Strategy regulations, the levees on these islands must be fully improved before any state funds can be spent improving levees protecting Rio Vista, Discovery Bay, Clarksburg, Courtland, Locke, or the east bank of Walnut Grove.

The “Ability to Pay” analysis for the Delta Levees Investment Strategy did not take into account that revenues from the State Water Project could be used to improve the Delta islands that are “critical for water supply,” even though two of the islands are owned by the Department of Water Resources. Most of the land on Sherman and Twitchell Islands was acquired by DWR in the early 1990s. The acquisition and conversion of the lands to grazing and wildlife uses allowed the Department of Water Resources to move the salinity compliance point for their contract with North Delta Water Agency upstream. This was estimated in to provide a benefit to critical period SWP deliveries of more than 100,000 acre-feet per year.

ATP mapAbility to Pay analysis for Delta Levees Investment Strategy (Arcadis)

The Delta Levees Investment Strategy also makes public investments in tidal habitat restoration on Dutch Slough and McCormack-Williamson Tract highest priority.  These islands are being restored as part of 8,000 acres of intertidal and subtidal habitat restoration required for mitigation of the impacts of the State Water Project and Central Valley Project. The Ability to Pay analysis for the Delta Levees Investment Strategy includes no revenues from the State Water Project for the habitat restoration, even though mitigation of impacts of the State Water Project is legally the responsibility of the State Water Project Contractors.

Thus the result of the analysis for the Delta Levees Investment Strategy combining pots of money for upgrades to urban Delta levees, upgrades to levees in the Delta primary zone, and habitat restoration, is that funding for protecting smaller Delta communities basically vanishes.  Combining the pots of money is contrary to the originally recommended cost allocation methodology for the DLIS, the Separable Costs — Remaining Benefits method  (SCRB.)  Under SCRB, costs and benefits of projects for water supply reliability and habitat restoration would have been analyzed both jointly and separately from protection of lives and property.

The DLIS also exposes the state to considerable liability.  Many of the levees protecting North Delta legacy communities are State Plan of Flood Control Levees.  The Central Valley Flood Control Association commented that “[d]eviating from existing definitions of levee maintenance that results in the state reducing investments in maintenance of SPFC levees will ultimately increase state liability and costs to pay for flood damage caused by levee failures.”  The Central Valley Flood Control Association comments reference the 1986 SPFC Project levee failure near Yuba City “which resulted in evacuations, deaths, and hundreds of millions of dollars in property losses.”   In the Paterno decision, this failure to adequately maintain the State Plan of Flood Control Levees resulted in liability by the state of $467 million.

Following the originally proposed SCRB cost allocation method would have avoided the issue with prioritizing non-project levees which protect water supply over SFPC levees which protect lives and property.  The slide below is from a presentation by Arcadis consultants for the Delta Science program peer review of the DLIS methodology.

DLIS cost allocation

Slide from presentation to Delta Stewardship Council on DLIS methodology

Because of the failure to follow the recommended cost allocation procedure, it is difficult to see how the DLIS is consistent with the legislative mandate that the Delta Plan “attempt to reduce risks to people, property, and state interests in the Delta by promoting effective emergency preparedness, appropriate land uses, and strategic levee investments.”

This post was updated on 8/21 to include links to comment letters on the Delta Levees Investment Strategy, more maps, and information on the originally proposed method of cost allocation.

 

 

 

Posted by: Deirdre Des Jardins | August 12, 2019

Delta tunnel: Sea level rise and elevation of the North Delta

On May 2, 2019, the Department of Water Resources published a fact sheet on “Modernizing Delta Conveyance Infrastructure Q&A.” The fact sheet states that the California Ocean Protection Council has recommended “that projects with a lifespan beyond 2050 be built to withstand 10 feet of sea level rise by 2100.” The Department of Water Resources is to be commended for recognizing the recommendations by the Ocean Protection Council.   Hopefully DWR will be using them in assessing climate change and “efforts to modernize Delta conveyance.” per Governor Newsom’s April 29, 2019 Executive Order.

DWR’s Q& A fact sheet goes on to state:

“A reliable underground conveyance system is needed to move high flows from the northern portion of the Delta, which is over 15 feet above sea level, to the point that it can be exported to water systems in the Bay Area, Central Valley and Southern California.”

The statement that the northern portion of the Delta is over 15 feet above sea level is a bit misleading.  The US Geological Survey gives the elevation of Hood as 7 feet.   Maps from LIDAR data show that elevations at Hood over fifteen feet are on River Road, on top of the Sacramento River levee.  To the east of the levee, Hood is at 7-8 feet of elevation.

Hoodelev

The difference between 15 feet and 7-8 feet is critical for the Delta tunnel engineering design. Under NOAA’s 10 foot sea level rise scenario, sea levels could rise 7-8 feet by 2080.  If the Delta tunnel was completed by 2040, that would be within 40 years of initial operation.

If North Delta levees are not adequately maintained and upgraded, there could be flooding even without sea level rise. Courtland, just south of Hood, is at -1 ft to 3 ft of elevation, and is subsiding.  The map below shows elevations from LIDAR data collected by DWR and URS corporation.

North Delta elev closeup

legend

Channel profiles from the US Army Corps of Engineers show that the Sacramento River bottom in the vicinity of Hood is over 20 feet below sea level (Mean Lower Low Water in Suisun Bay.) If there was widespread levee failure in the Delta, it is unclear how far salinity would intrude up the Sacramento River at low flows.

SacRiverbottom

 

DWR’s assessment of “efforts to modernize Delta Conveyance” should include a discussion of whether further modeling is needed to evaluate salinity intrusion at the North Delta intake locations with 5-10 feet of sea level rise.

This post was updated on 8/14 to include an elevation map of the North Delta.

Posted by: Deirdre Des Jardins | August 6, 2019

CWR comments at the Water Board’s Water Portfolio Listening Session

The State Water Resources Control Board held a listening session to receive input on the Water Portfolio.  Deirdre Des Jardins made the following comments for California Water Research on deep adaptation to extreme impacts of climate change — droughts and flooding.

Water agencies need to plan for reliability of ecosystem water during droughts. There were far too many water agencies that came before the Water Board in 2014 to request relaxation of minimum instream flow standards. This should be the last resort during droughts, and only done after implementing Stage 4 drought curtailments.  If California water agencies fail to do this, aquatic ecosystems will not survive climate change.

The Water Board also needs better funding for its core missions. In 2003, at the beginning of the state’s budget crisis, the legislature cut all general fund funding for the Water Board’s water rights division. The Legislative Analyst’s Office noted that this budget cut would increase the backlog of water rights applications.

This is now a major issue with SGMA. The solution is not for the Board to streamline water rights applications statewide, but to provide adequate funding for the Board to evaluate existing permits and instream flow needs.

Another essential need is for critical evaluation of whether climate adaptation projects will actually provide the benefits that they claim. It is being claimed that Sites Reservoir provides flood protection. But it’s an offstream reservoir. It is being claimed that the Delta tunnel will provide mitigation for sea level rise, but the performance of the North Delta intakes has never been evaluated for current estimates of high sea level rise.

The Department of Water Resources has proposed that the state provide vastly increased subsidies for water supply projects. But in adapting to climate change, the state needs to first prioritize funding for protecting vulnerable communities that do not have the resources to adapt to climate change. Their needs include not just drinking water, but also protection from inundation due to flooding or sea level rise. If we continue to fail to adequately fund flood protection, the future consequences could be disastrous.

Finally, our state patterns of land use are unsustainable. Not only do we have massive groundwater overdraft in the San Joaquin Valley, satellite mapping showed 955,000 acres on the west side of the San Joaquin Valley that is moderately to severely impaired by salinity. We simply do not have the resources, either with surface water or with funding, to sustain these patterns of land use and also deal with the disruptions of climate change.

Posted by: Deirdre Des Jardins | August 6, 2019

DWR rescinds engineering performance standards for Delta tunnel

The Department of Water Resources delegated the design and construction of the WaterFix project to the Delta Conveyance Design and Construction Authority in the October 2018 Joint Exercise of Powers Agreement.   The Joint Exercise of Powers Agreement included performance standards for the engineering design of the project. The performance standards included requirements that the Delta conveyance be designed to withstand a maximum earthquake, and to have a 100 year lifetime.

The June 2019 Amendment to the Joint Exercise of Powers Agreement rescinded the engineering performance standards.  This should be of concern to water agencies evaluating whether to participate in the Delta conveyance project.

The requirement for a 100 year design lifetime is particularly important because of sea level rise. The impact of sea level rise on the North Delta intakes was last evaluated in 2010.   The hydrodynamic modeling assumed 55 inches of sea level rise by 2100, which is about half that of current maximum estimate of 10 feet.

SLR 2200

US Army Corps of Engineers   Sea level rise in the Delta through 2200

The 2010 modeling also evaluated the impacts of widespread levee failure, but used a grid from the Delta Risk Management Strategy modeling that only went as far north as Isleton and Bouldin Island.   So the modelling implicitly assumed that only levees in the South Delta would fail.

grid

 Grid used for modeling of salinity intrusion for DRMS and North Delta intakes

For these reasons, California Water Research  has recommended that more hydrodynamic modeling be done to assess the impacts of extreme sea level rise on the previously proposed North Delta intake locations.

The Delta Independent Science Board made similar recommendations in their 2014 review of the Delta conveyance project, stating,

If the effects of major environmental disruptions such as climate change, sea-level rise, levee breaches, floods, and the like are not considered … one must [not] assume that the actions will have the stated outcomes.

Without such an assessment, there is insufficient information for decision makers to evaluate the Delta tunnel as a water supply project.

Governor Gavin Newsom stated in his February 12, 2019 State of the State address that he did “not support the WaterFix as currently configured.  Meaning, I do not support the twin tunnels. But we can build on the important work that’s already been done. That’s why I do support a single tunnel.”  The meaning of Governor Newsom’s statement is the subject of active negotiations between the Department of Water Resources (DWR) and the State Water Contractors (SWC.)

DWR and the SWC have begun negotiations on a potential State Water Project contract amendment to pay for a single Delta tunnel.  Under a settlement agreement with Planning and Conservation League over the Monterey amendments, the negotiation meetings are required to be public. The first negotiation meeting was held on July 24, 2019.

At the July 24 meeting, the State Water Contractors presented a First Offer to DWR.  The State Water Contractors seek an Agreement in Principle that would allow the SWC to define the Delta tunnel capacity and general configuration, including the tunnel alignment, number of intakes, and pumping station capacity.

Meanwhile, in consideration of Governor Newsom’s direction, the Delta Conveyance Design and Construction Authority is reportedly considering four potential alignments for the Delta tunnel project in the DCA’s engineering design process.  The potential alignments include the “previously preferred” Waterfix tunnel alignment, and one nearer to I-5 that would avoid some of the major impacts from project construction on Delta recreation, Delta tourism, and Delta legacy towns.

Metropolitan Water District has bought two of the Delta islands in the WaterFix project main tunnel alignment, Bouldin and Bacon Islands, and CalTrans has constructed an interchange for the project at Highway 12 on Bouldin Island.  So it seems likely that the State Water Contractors are proposing that the main Delta tunnel alignment not change.

Bouldin tunnel

WaterFix main tunnel alignment on Bouldin Island with tunnel muck areas

For operations, the State Water Contractors are proposing that the Delta tunnel be a State Water Project facility, integrated into the State Water Project.  The SWC propose to define “Delta Conveyance Project Water,” which would be “the additional amount of total SWP water that can be conveyed with the Delta Conveyance Project compared to the amount that can be conveyed without the Delta Conveyance Project.”

The  State Water Contractors are also proposing that water agencies opt in to participate in the Delta tunnel project.  SWC who choose to participate would pay for a share of the available Delta tunnel capacity, up to their Table A allocation. The proposal states that the SWC believe that the Delta tunnel would be fully funded by the opt in framework, but propose an iterative procedure for determining participation as the design of the Delta tunnel is developed.

Meanwhile, the Delta Conveyance Design and Construction Authority is pushing forward with engineering work on the Delta Conveyance project and submitting the bills to DWR.  Unless agreement is reached, DWR may run out of funds to pay the DCA.

Further negotiation meetings are scheduled for July 31, and August 7, 14, 21, & 26.

Posted by: Deirdre Des Jardins | July 16, 2019

Speculative financing for Delta tunnel engineering work

The Delta Conveyance Design and Construction Authority (DCA) is a Joint Powers Authority created in 2018 by Metropolitan Water District, Santa Clara Valley Water District, Kern County Water Agency, and the State Water Contractors. The DCA was delegated the powers of the Department of Water Resources to design and construct the WaterFix / twin tunnels project.

In January of 2019, the DCA signed a $93 million contract with Jacobs Engineering for engineering design services for the WaterFix project and a $75 million contract with Fugro for geotechnical services.  In April, the DCA signed a contract for $40 million with Parsons Transportation Group for a Project Management Information System, cost and schedule controls, and program reporting.  But at the direction of Governor Newsom, all WaterFix project approvals were rescinded on May 2, 2019.  Work has nevertheless continued under the engineering contracts.

The continuing engineering work is being financed under a June 2019 amendment to the WaterFix Joint Exercise of Powers Agreement (JEPA,)  The amendment allows DWR to authorize and pay for design work on a single tunnel project, retroactive to May 2019.  The budget in the JEPA amendment (shown below) states that the DCA is planning to spend over $100 million for each of fiscal years 2019-2020, 2020-2021, and 2021-2022.

DCA budget and schedule

The DCA appears to be attempting to continue the original WaterFix engineering design schedule as much as possible, given the new direction on the project.   The WaterFix project engineering design was originally scheduled to be completed in 2022.

But how is the engineering work on the single tunnel being paid for, given that all project approvals were rescinded?   The meeting materials for the July 2019 Design and Construction Authority Board meeting show no current funding commitments. The cash flow projections (shown below) show the DCA is relying on a $19.7 million loan from DWR for expenses for the next few months. Future cash flow relies on yet-to-be-made commitments by State Water Project contractors starting in September 2019.  A footnote below the graph states that the majority of State Water Project contractors are “anticipated” to “seek and receive funding approval from their respective Boards between November 2019 and February 2020.”

DCA 7-19 cash flow

The DCA is also signing a $10 million lease for office space at 980 9th Street. According to the July meeting packet, the DCA Director is seeking authorization for a letter of credit from a bank that the landlord could draw on as necessary “if the DCA defaults on the lease.”

 

Posted by: Deirdre Des Jardins | July 8, 2019

Assessing the Delta tunnel project as a seismic upgrade

Governor Newsom’s April 29, 2019 Executive Order mandated that the California Natural Resources Agency and the California Environmental Protection Agency assess “current planning to modernize conveyance through the Bay Delta with a new single tunnel project.”

Part of the agencies’ assessment of that planning should include an independent, objective assessment of the Delta tunnel’s performance in a large earthquake. The assessment needs to look into why Metropolitan Water District’s analysis of whether the tunnel lining will survive a large earthquake assumes the tunnel is constructed in very dense soil.  This assumption is questionable.

100917_0503_WaterFixtun2.png

In April of 2018, California Water Research collaborated with the Sierra Club and other Southern California environmental groups to send a letter to the General Managers of Metropolitan Water District, and Kern County Water Agency, and the CEO of Santa Clara Valley Water District, explaining that the Delta tunnels were not being designed to withstand a Maximum Considered Earthquake on nearby faults. The letter concluded,  “[t]he Department of Water Resources and Metropolitan Water District must analyze the performance of the Delta tunnels for all seismic hazards in the Delta, including the.. Maximum Considered Earthquake.”

MWD commissioned an evaluation of the performance of the proposed Delta tunnel lining for a Maximum Considered Earthquake in the Delta, a 2% in 50 year, or 1 in 2,475 year event.  The July 2018 analysis concluded the tunnel lining design would perform adequately and no changes to the design were needed. (Arup 2018.)

But there were major limits to the new analysis by Arup. The analysis for a Maximum Considered Earthquake only considered ground shaking at Clifton Court. The analysis also assumed that the soil column at Clifton Court was very dense. Based on this assumption, the analysis concluded that the ground shaking at the depth of the tunnel was about one-third that of the ground shaking on the surface.

chart seismic

As explained below, the assumption that the soil column at Clifton Court is very dense is inconsistent with geologic maps of the deep sedimentary deposits in the Delta. The conclusion that ground shaking at the depth of the tunnel is one-third that of the ground shaking on the surface is also not consistent with measurements from a down-hole seismic array at another site with deep sedimentary deposits, La Cienega in Southern California (Grazier 2004.) Measurements at La Cienega show that for strong earthquakes, ground shaking at the proposed Delta tunnel depths is about 70% of that on the surface (Hu 2005.)

Seismic hazard maps from the California Geologic Survey show no regions in the Delta near Clifton Court Forebay with very dense soils. The CGS map below shows the soil density for areas in the Delta near Clifton Court. (CGS 2018.)   Interpreting the CGS map requires a little explanation.

Geologists and geotechnical engineers estimate the density or stiffness of soils with shear wave velocities (Vs.)  For earthquake engineering, they consider the average shear wave velocity over the top 30 meters (100 feet) of soil.   Average shear velocities above 750 m/s correspond to rock. Average velocities above 360 m/s correspond to very dense soils. Velocities above 180 correspond to stiff soils. Velocities below 180 correspond to soft soils.

The CGS map shows that, in general, the only very dense soils near Clifton Court are in the Diablo Mountain range (at the bottom left corner.)  The soils at Clifton Court are generally stiff (Vs = 294.)  The soils at Bacon Island are generally soft (Vs = 176.)

Woodward quadrangle

Perhaps the sediments Clifton Court Forebay increase in density with depth?   The graphs below show shear velocity vs depth in two boreholes at Bacon Island and Clifton Court, from Kishida 2009. There start to be layers of very dense soil at Clifton Court at about 25 meters (82 feet depth.)  The graph shows essentially no layers of very dense soil for Bacon Island.

Kishida

It is unclear how MWD could have concluded that soils at Clifton Court are “very dense,” except by cherry picking the properties of deep layers of soil.

For evaluation of the seismic performance of the Delta levees in the Delta Risk Management Strategy, on the other hand, DWR’s contractor cherry picked the lowest shear velocity values from specific boreholes.   This was criticized by the US Geologic Survey as not standard engineering practice.

If the DWR’s contractors analyze the seismic performance of the Delta levees as if they were built entirely on soft soils, and MWD’s contractors analyze the performance of the Delta tunnel lining as if it was built entirely in very dense soils, it will likely result in a large over-estimation of the seismic benefits of the Delta tunnel.

An objective, unbiased analysis of the benefits of the Delta tunnel as a seismic upgrade should use the same geotechnical assumptions for both the “without project” conditions and the “with project” conditions.

References

Arup, Seismic Review of Tunnel Liner Performance, Appendix M, Conceptual Engineering Report, California WaterFix Byron Tract Forebay Option,  2018. Available at https://www.waterboards.ca.gov/waterrights/water_issues/programs/bay_delta/california_waterfix/exhibits/docs/petitioners_exhibit/dwr/part2_rebuttal/dwr_1304.pdf

California Geological Survey, Seismic Hazard Zone Report for the Woodward Island 7.5-Minute Quadrangle, Contra Costa County, California 2018.  Available at http://gmw.conservation.ca.gov/shp/EZRIM/Reports/SHZR/SHZR_121_Woodward_Island.pdf

Graizer, V & Shakal, A. Recent Data from CSMIP Instrumented Downhole Arrays. AGU Fall Meeting Abstracts, 2004.  Available at https://www.researchgate.net/publication/252102057_Recent_Data_from_CSMIP_Instrumented_Downhole_Arrays

Hu Jin-jun & Xie Li-li. “Variation of earthquake ground motion with depth,” Acta Seimol. Sin. (2005) 18: 72. DOI:10.1007/s11589-005-0008-x.   Available at http://link.springer.com/article/10.1007/s11589-005-0008-x

Kishida, Tadahiro & Boulanger, Ross & A Abrahamson, Norman & W Driller, Michael & M Wehling, Timothy. Site Effects for the Sacramento-San Joaquin Delta. Earthquake Spectra. (2009) 25 10.1193/1.3111087. Available at https://www.researchgate.net/publication/256932489.

Schaefer, J.  Seismic Review Comments (and Responses) on Technical Memorandum Delta Risk Management Strategy (DRMS) Phase 1 Draft 3 Topical Area: Levee Vulnerability. US Army Corps of Engineers, April 11, 2008.  Available at https://cah2oresearch.com/wp-content/uploads/2019/07/Seismic-Review-Comments-and-Responses.pdf

 

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