Delta Stewardship Council hears a BDCP update, plus a frank discussion on tunnel size and capacity

Delta bridges
Photo credit: Department of Water Resources

At the Delta Stewardship Council’s meeting on August 22, Karla Nemeth, project manager, and Gordon Enas, engineer, were there to brief council members on the Bay Delta Conservation Plan (BDCP).  The presentation included an overview of the project and how it fits in to the Delta Plan as well as a in-depth discussion of the capacity of the tunnels.

The Delta plan’s recommendations call for completion of the BDCP successfully but consistent with the Delta Reform Act’s requirements by December of next year,” said Dan Ray, Chief Deputy Executive Officer.  “It’s important that it’s successful because it can help contribute to recovery of Delta fish and the ecosystem, partly by relocating the diversion points so we reduce entrainment of fish and other adverse impacts in the South Delta.  It also includes other conservation measures that can help restore the Delta ecosystem and address other stressors that damage the Delta’s ecology.  It can help improve reliability if it’s successful because it could reduce the regulatory uncertainties that confound management and diversions out of the Delta, provide more operational flexibility and increase the resiliency of our systems to the effects of floods and earthquakes.”

Because the BDCP is so important and because when it is approved, it will become part of the Delta Plan, we want the BDCP to work.  It’s essential to us since it will become part of our plan, that we do what we can to help the BDCP staff and participating agencies produce a plan that’s going to be effective and that will dock as smoothly as it can into the Delta Plan,” said Mr. Ray.

In preparation for the release of the public review documents in October and the Council’s role as a CEQA responsible agency, the staff has arranged for the Council to have a series of briefings over the next few months.  This first briefing will be an overview of the BDCP and how the BDCP fits with the objectives of the Delta Plan.  September’s briefing will focus on the costs, the governance structure, and the adaptive management program and October’s briefing will focus on the construction of the facilities and the anticipated impacts to the Delta.


Karla Nemeth began by congratulating the Council on completion of the Delta Plan.  “That’s an enormous accomplishment and I know very well how challenging those plans are to put together, so congratulations on that,” she said.

The administrative drafts of the conservation plan and the EIR/EIS were released earlier this year.  “We received comments on the administrative draft of the EIR/EIS from the federal lead agencies and those progress memos were made available to the public.  We’ve also received voluminous comments as one might expect from many local agencies who are cooperating agencies in the NEPA process, so folks are at work right now resolving those comments and preparing the public review draft, so the public review draft will look different than the one that has been provided to date.”

They are working to reduce the number of significant and unavoidable effects that were identified:  “We are doing quite a bit of work toward reducing those or identifying appropriate mitigation measures, so that’s a very important step in our process in terms of understanding on a more granular level what the potential impacts are in the Delta, how we work with them, and how that works with the Delta Plan in terms or preserving Delta as place and some of the legacy communities in the Delta,”  Ms. Nemeth said, adding that they are engaged in discussions with Dr. Goodwin and the Independent Science Board on revisions to the governance chapter and the adaptive management plan.

BDCP KN Slide 3We do have two goals that mirror the goals that the Delta Plan is working under which is to improve water supply reliability and restore the Delta ecosystem,” she said.  “In broad brush, we have been developing specific concrete actions that improve the operational flexibility of the state and federal water projects, reduce the conflicts between the operations of those projects and native fisheries, and secure water supplies from seismic risk and potential flooding and long-term sea level rise.”

The new diversions that are part of this plan are diversions that are anticipated to come online about 10 to 15 years after a plan would be approved,” said Ms. Nemeth, “so the plan itself is not contemplating near term actions in the Delta or physical actions in the Delta to address some of the other ideas that have been on the table in recent years for improvements to water supply reliability.”

The Plan proposes to protect and restore the Delta ecosystem including the restoration of critical habitat and restoring more natural flows, so those things speak directly to elements of the Delta Plan.”

As a conservation plan under federal endangered species law and the state’s Natural Communities Conservation Planning Act, the conservation plan needs to meet very specific objectives to provide for the recovery of species under the law,” she said, “and that’s essentially framed by the biological goals and objectives and the analysis that determines that our collective suite of actions can achieve those biological objectives over time, so those are things that are foundational to the regulatory context of the plan.”

BDCP KN Slide 5For water facilities and operations, the plan proposes three new north Delta intakes,” said Ms. Nemeth.  “We are identifying 30 miles of gravity fed tunnels, and we’re also identifying operable gates at the head of Old River and other nonphysical barriers to separate water supplies for human use from the fishery needs of the estuary.”

Recently we had our engineer Gordon Enas describe some of the actions that the Department has taken to reduce some of the physical impacts of the footprint of the proposed facilities,” said Ms. Nemeth.  “We have reduced the height of the proposed pumping plants from 60 feet to 30 feet, we have reduced the number of tunnel shafts and reduced some of the roadway impacts.  We have a smaller intermediate forebay; we had originally proposed a 750 acre forebay near the town of Hood that has been reduced to 40 acres partly … because we took a look at the ability to make some modifications to Clifton Court forebay so bringing that storage need that we have for the system to another location in the Delta that would lessen impacts on Hood as a legacy community.”

The other thing that we are working on and can’t be mentioned enough is just the fundamental infrastructure change in moving the intakes for the state and federal projects as the primary point of diversion to the Sacramento River and the opportunity it creates for more effective fish screening than is currently available with the configuration at the south end of the Delta,” she said.

BDCP KN Slide 7We do have extensive flow criteria for those intakes,” said Ms. Nemeth.  “For example, we have criteria for bypass flows or what kind of flows need to be in the Sacramento River before water can be delivered as additional water is available in the system and what is the appropriate rate of diversion to ensure that particularly juvenile salmon can move past the screens unharmed.  But the plan itself also includes flow criteria in Old and Middle River.  The proposal includes an operable barrier at the head of Old River, it also includes outflow conditions, spring outflow, fall and summer and winter consideration for outflow criteria.  Many of these are new criteria over and above the outflow conditions that we have today.  This is all a part of the notion that the conservation plan is promoting the recovery of 11 aquatic species, including longfin smelt, which is not part of the existing regulatory regime that governs the system.  So it is extensive and this really does fit with the Delta Plan’s policies about restoring more natural flows to the system.”

The BDCP habitat restoration inventoried habitat types available in the Delta and identified the most appropriate locations for terrestrial species both biologically and considering climate change, she said, adding that a large part of the conservation effort involves habitat on working agricultural lands and creating habitat for fish species.  “The Plan has identified 30,000 acres of habitat restoration to occur in the next 15 years, and there is tremendous interest across both the project operators and the biological agencies in understanding in much more detail how habitat restoration can help these fish species recover,” said Ms. Nemeth.  “There’s a lot that we don’t know.  There’s consensus around the notion that it needs to be done, but we need to get some habitat restoration in the ground to understand better what the effects of that restoration would be.”

BDCP KN Slide 10We have heard from Delta communities about their concerns regarding habitat restoration and the potential conversion of agricultural lands, and what might be done to offset or greatly reduce the impact on Delta agriculture, she said.  “In the administrative draft of the EIR/EIS, we have developed a section around environmental commitments that really is the product of discussions between DWR and Delta community members about a whole host of strategies that could be put in place to maintain the agricultural economy in the Delta.  Some of those things fit within BDCP mitigation, some of them do not. I think that is an area that is really ripe for further discussion with Council staff and the implementation committee to understand how we might move those kinds of specific actions forward. …I think that’s one area where we can have closer collaboration between the conservation plan and the Delta plan and identify some near term strategies.”

There are conservation zones for the habitat for the 45 terrestrial species.  “It’s really meant to be a blueprint for where habitat might go with specific targets, so there’s flexibility designed into the plan,” said Ms. Nemeth.  “It is also designed to work better with other planning processes underway in the Delta, including the Delta Plan and some of the economic sustainability efforts underway at the Conservancy and the Delta Protection Commission.”

BDCP KN Slide 11The plan also includes several methods to address other ecological stressors in the system; methylmercury management, reducing illegal harvest of species, urban stormwater treatment,“ she said, adding that “if the permit were approved, on Day 1 we start restoring habitat and implementing the other stressors measures as we start implementing a long term conveyance solution in the Delta.”

Chair Isenberg asked Ms. Nemeth, after the release of the public review draft, how long of the public comment period they were considering.

We’re looking at a 90-day public review period, but we do realize that would fall over the holidays,” she said.  “We are looking at about a 90-day meeting with public meetings around the public draft plan in January of next year.”  She said the plan will hopefully be completed by summer of 2014.

There is an overall state need for water supply reliability, said Ms. Nemeth.  “We are certainly aware that not everyone in the state benefits from the improved water supply reliability associated with BDCP, and the needs extend beyond that so we need to look towards other investments that the state needs to make.”  (Note: this statement is clarified later in the discussion.)

BDCP KN Slide 12The conservation plan is contemplating several sets of flow criteria, she said.  “There is outflow criteria associated with different seasons and spring outflow for particular species which are not part of the regulatory regime right now, but the plan is contemplating as permitting criteria for the conveyance facilities.”

The yield of the project under high outflow conditions that produces a yield similar to today’s current conditions of about 4.7 MAF, she said.  “We identify processes for testing the habitat restoration and testing the effectiveness of some of these flow criteria in a decision tree that suggests that if we got the biological response that we are seeking and we are seeing the improvement in species that there is a potential that the yield from the system could increase to 5.6 MAF.”

However, for the purposes of the economic analysis, they used the high outflow scenario’s yield of 4.7 MAF.  “With BDCP stabilizing existing water supplies with a yield of about 4.7 MAF, our most recent economic analysis demonstrates about a $5 billion economic benefit that is mostly the result of reducing the risk of future shortages and how important that is to the California economy, for jobs and for the broader economy that is served by the state and federal water projects,” she said.  “We also know that there’s downward pressure on water supplies coming out of the system because of climate change and that we’ll need to continue to invest in alternative water supplies so we can continue to meet California’s water needs, so it’s not an ‘either-or’ with this investment in a conveyance fix in the Delta.”

Different regions of the state have different needs, depending upon their water supply portfolio and what’s available to them locally, and all of those water supply alternatives are examined in the California water plan update,” she said, noting that the plan is expected to be released in draft form in September and finalized in January of 2014.    “That is going to help us understand what the BDCP proposal provides from a water supply infrastructure perspective and frames up some of the other investments that the state will need to make in other kinds of supplies to create a broader California water plan that meets some of the climate change needs that we know exist and that address some of the aging infrastructure needs that we know all Californians share.”

DSC Karla 1I read in an editorial in the Sacramento Bee recently suggesting that the conservation plan didn’t provide a look at water supply availability in different hydrological years,” said Ms. Nemeth.  “The plan does; we do have criteria for how the system would be operated in critically dry, dry  year conditions, wet conditions, and we have yields associated with that.  It is also a good framework for understanding better what the storage needs are in the state, both below ground and above ground, and potentially how we start addressing back to back critically dry years.   Part of the enormous task of the conservation plan has been to focus laser-like on what do we think we can sustainably export from the system while meeting the goal for helping these species recover in the Delta, and what the outcome of this particular process has on the potential for storage in this state and potential for other statewide investments in recycled water, improved water use efficiency and other areas.”

Councilwoman Gloria Gray:  I thought I heard you say that BDCP does not benefit everyone in the state, and that there are some areas that it does not.  Can you expand on that?

I think the point that I was wanting to make was that BDCP, as a conservation plan, secures water supplies for state and federal water contractors south of the Delta, so there is clearly a benefit to those particular users in the system,” said Ms. Nemeth.  “I think all Californians benefit from improvements in water supply reliability given the interconnectedness of the state’s economy, especially regionally, so I certainly didn’t mean to imply that benefits were limited to only one set of users, but we do have broader water supply needs that depend on where you are regionally within the state and we need to look to address those as well.”

The statewide economic benefit analysis did not include the benefits of a restored ecosystem, she said.  “We’ll probably introduce that kind of information over the course of the next several months; it looks to quantify the benefits that all Californians would realize with a restored Delta ecosystem.”


Executive Officer Chris Knopp asked Gordon Enas if he wanted to address the letter written by Friends of the River, the Environmental Water Caucus and others that suggests that the tunnels are larger than when they were proposed at 15,000 cfs ?

Back when we were looking at a much larger system, 15,000 cfs, it was really a pressurized pipeline,” said Mr. Enas.  “By going to an all-gravity system, the main control in a gravity system is the friction that you have  … with a pressurized line you can use a much more constricted pipeline, but once you go to gravity, you don’t have that pressure that is artificially imposed by a pumping system and all you are relying on is gravity to overcome friction in the line.  By increasing the size of the tunnel, you reduce the amount of friction, but you do need to increase it and that’s why we’ve gone from a 33 foot to a 40 foot tunnel.”

DSC Gordon 1I’ll make an analogy between what a lot of farmers in the valley will use, because farmers use gravity to run their irrigation systems in many cases,” said Mr. Enas.  “What we’ve gone to is much like a standpipe in a farm.  We’re pumping the water out of the river into our forebay, which really acts like a standpipe, so we’ve elevated the head and the elevation in the forebay, and the weight of that and the elevation difference in that water is really what pushes the water through the tunnel, so it’s really the difference in the hydraulic head that is now the pumping mechanism by which the water moves through the system.”

The limitations of your ability to force water through the gravity system also has something to do with the capacity performance of the system overall,” said Chair Phil Isenberg, “and one of the issues that Mr. Knopp was getting at was the question if you can run it continuously and constantly send water down at the highest possible volume, but as I understand it, without pressurization, there’s a problem with that.”

We’ve sized the tunnel to be able to handle the capacity that we have now which is 9000 cfs,” said Mr. Enas, “so if we wanted to move more than the 9000 cfs, we’d have to either increase the amount of intakes we have on the river because that’s how we’re sizing it so we’d have to add more on to it, or … well, that’s really the control point.  If the intake is 3000 cfs, we can’t divert more than that regardless of what the actual tunnel can move.  That’s really where our limitation is at is what we can really divert off the river.

It strikes me that this whole discussion – size, how much, guarantees and all of that – is kind of the classic difference between politics and maybe public policy which somehow acts as if we can guarantee at all time and in all places for all people and all things exact configurations,” said Mr. Isenberg,  “but a system that utilizes a natural resource like water is subject to the vagaries of the climate, weather patterns and availability of supply, and it’s also subject to the vagaries of the system as it’s designed and built.”

If I could take a crack at answering what the fear is a little more directly,” said Ms. Nemeth.  “We have a proposed 9000 cfs intake capacity and we have tunnels that are bigger than that because they need room to allow for gravity flow.  It isn’t simply that later on, another intake could be added and the capacity of those tunnels could be used to move even more water.  That would actually require a lining inside the tunnel and substantial reconstruction of the project to do that, and so …”

Unlikely to be a CEQA exemption,” said Mr. Isenberg.

Yes, unlikely to be a CEQA exemption,” said Ms. Nemeth.  “I think DWR has made it clear that this is a project that would be done only once, and so the capacity needs to be a capacity that looks at a 100-year or 200-year need, and that’s the reality we’re looking at.  We’re looking at 200-year facilities here.”


  • Click here for the staff report for this Council item.
  • Click here for Gordon Enas’ explanation of the recent changes made to the BDCP.
  • Click here for the Friends of the River letter.
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