Reality Check of California Water Fix Model results in a Critical Flow Year

by William Fleenor

The San Joaquin (left) and Sacramento (right) rivers meet near Antioch, an important location for X2 management during dry years. (Image credit: Carson Jeffres)

In 2008 a group from the Center for Watershed Sciences (including this author), joined by an economist from the Public Policy Institute, published findings that suggested that an alternative conveyance for Sacramento River water might improve ecological conditions in the Delta and improve reliability for Delta water exports [1, 2].

The original 2013 draft of the Bay Delta Conservation Plan (BDCP) (DEIR/EIS) included several alternatives using tunnels for Delta conveyance [3].  Long-term planning of this nature requires greatly simplified hydrodynamic models to simulate decades of data to estimate performance under a range of variable conditions.  These models also require manipulation to account for physical effects they don’t simulate (e.g., changes in habitat and sea-level rise conditions for which future management is unknown).

The manipulation involves simulating habitat changes and sea-level rise with other models that have far more physically accurate numerical computations, but which run too slowly to simulate details over many decades.  With results from the more accurate detailed models, a simple model can be calibrated to simulate a fuller range of conditions.

For the BDCP, the results of slow, more detailed 2- and 3-dimensional models (already imperfect) are incorporated into DWR DSM2, a faster 1-dimensional model, and run for a longer period, producing additional errors.  Results from DSM2 are then used to create an artificial neural network (ANN) for salinity intrusion used in the still-faster DWR CalSim II model to simulate the decades of planning for the DEIR/DEIS (more potential errors).  CalSim II is a monthly model that cannot resolve issues occurring on a shorter time scale (e.g., spring/neap tidal cycles, real-time flow changes, 14-day average compliance requirements, etc.).  Nearly all decisions made in the DEIR/DEIS were made using long-term averages of monthly averages of CalSim II results.

An earlier review of the DEIR/DEIS [4] pointed out this potential cascade of errors and recommended that the higher dimensional models be simulated for shorter periods of stressful conditions (e.g., drought) to corroborate the results.  The corroboration would help ensure that decisions made from the results were reasonable.

The final EIR/EIS [5] of the California Water Fix (FEIR/EIS) was released December, 2016 and still lacks such efforts to corroborate the results of the long-term simulations.

Here, I applied the 2-dimensional model, RMA2, to simulate Delta flows and salinity with and without the CWF for conditions of water year 2008, a dry year.  It is the same software used in CWF to provide input to modify DSM2 for habitat restoration.  It is the last year for which Clifton Court Forebay intake data have been made publicly available. (It would be easy to argue that not releasing Clifton Court Forebay operations data is a violation of California law (SB54).  These data are vital for detailed modeling of Delta flows and water quality.)

Figure 5-53 (Fig 1 below) in the FEIR/EIS summarizes results with a long-term average of ~3.5 MAF of water exported in dry and critical years with ~1 MAF of that through north Delta diversions (NDD).  Actual exports for water year 2008 were 3.43 MAF, which was similar to the long-term average and used for simulation with ~1 MAF taken from the new NDD intakes.

Figure 1 Figure 5-53 from the FEIR/EIS demonstrating exports in dry and critical water years

In the initial effort, I could not apply every operational restriction identified in the FERI/EIS, lacking time and money to re-write internal model code.  I honored first pulse constraints and sweeping velocity constraints past the NDD locations.  Beyond those, I applied the maximum volume of intake at the NDD locations to produce the maximum change throughout the Delta.  Using these criteria, the NDD volumes exceed 60% of total exports during the highest Sacramento River flows (6,000 of 11,000 cfs), but less than 30% during lower flow periods (Fig 2).

Figure 2. Modeled exports from NDD and south Delta pumps.

This modeling effort demonstrates that the work of the FEIR/EIS should hold true during low-flow drought periods, and I commend those involved with the modeling.  But I remain critical of their lack of providing detailed model corroboration.

One of the most watched Delta regulations is X2, the distance in kilometers from the Golden Gate Bridge of 2 psu (practical salinity unit) near the bottom along the path of the Sacramento River.  Since X2 is usually downstream of the confluence of the two rivers, and my analysis made no changes in net outflow, the only differences occur in fall and winter (Fig 3).  NDD exports only produced minor changes in X2 that could be easily managed.

Figure 3. Changes in X2 during water year 2008 by CWF and Base case

The key to salinity in Delta and export water is salinity in Franks Tract (FT).  Once salt gets into FT it is pulled to the pumps.  A graph of salinity changes in eastern FT helps explain when NDD affects Delta salinity (Fig 4), which includes the ratio of Total Exports to NDD.

Figure 4. Eastern Franks Tract EC changes along with Total Exports/NDD ratio.

Interestingly, salinity in Franks Tract falls during lower flow periods with CWF.  Only during the highest Sacramento River flows with NDD exports exceeding 50% of Total Exports does salinity in Franks Tract increase during CWF simulation.  The improvements during the lower flow periods result from a lower proportion of inflow into FT from False River and Dutch Slough, and a higher percentage of inflow from the Old River connection at the San Joaquin River (SJR) (supplied by water from the San Joaquin River and Sacramento River via the Delta cross channel).

The greater salinity near the end of January correlates with abrupt increases in the ratio of Total/NDD exports and the lack of Sacramento River water through the closed cross-channel gates.  However, for Total/NDD export ratios approaching 50% in May-June, salinity still falls with CWF.  A follow-up simulation capping the Total/NDD ratio to 50% shows that any increases in salinity can be managed.  Not shown is the simultaneous pulse of salinity up the San Joaquin River contributing to the January increase.  All these effects are manageable with proper insight and monitoring of the Delta.

For any given total export rate, any NDD export should reduce the negative net Old & Middle River flows (OMR) from through-delta pumping, and create more natural flow patterns through the Delta.  With proper monitoring and management, the negative OMR flows could likely be eliminated during critical times.  Creating a more natural flow pattern while reducing fish ‘salvage’ at the south Delta pumps and producing a system with improved reliability while maintaining Delta water quality goals would seem to benefit  all interests.

William Fleenor is an affiliate of the U.C. Davis Center for Watershed Sciences. His research focuses on the development and application of numerical hydrodynamic models for water management.

Further reading

[1] Lund, J., E. Hanak, Wm. E. Fleenor, R. Howitt, J. Mount, and P. Moyle, Comparing Futures for the Sacramento-San Joaquin Delta, Public Policy Institute of California, 2008, 241 pg

[2] Fleenor, W., E. Hanak, J. Lund, and J. Mount, “Delta Hydrodynamics and Water Quality with Future Conditions,” Appendix C to Comparing Futures for the Sacramento-San Joaquin Delta, Public Policy Institute of California, San Francisco, CA, July 2008.

[3] ICF International, 2013, Administrative Draft Environmental Impact Report/Environmental Impact Statement for the Bay Delta Conservation Plan, prepared for Califronia Department of Water Resources, U.S. Bureau of Reclamation, U.S. Fish and Wildlife Service, and National Marine Fisheries Service

[4] Mount, J., Wm. Fleenor, B. Gray, B. Herbold, and W. Kimmerer, 2013, Panel Review of the Draft Bay Delta Conservation Plan, prepared for The Nature Conservancy and American Rivers

[5] ICF International, 2016, Final Environmental Impact Report/Environmental Impact Statement for the Bay Delta Conservation Plan/California WaterFix, prepared for Califronia Department of Water Resources and U.S. Bureau of Reclamation

Posted in California Water, Delta | Tagged , | 3 Comments

Groundwater Recovery in California – Still Behind the Curve

by Thomas Harter and Bill Brewster

California has a unique and highly variable climate in which drought reoccurs periodically. California began this century in a dry period from 1999 to 2005, and experienced droughts from 2007 to 2009, and 2012 to 2016.  Such wet-dry cycles can be seen in Figure 1, which shows total rainfall amounts per water year (water years run from October 1 to September 30). These dry cycles greatly affect the state’s groundwater basins.

Figure 1: California statewide annual precipitation. Source: DWR 2017

Despite the current storms, the 2018 water year is well below average, and that pattern may continue. But from a groundwater perspective, it’s clear that dry is the new norm.

Why do groundwater basins continue to suffer the impacts of drought long after the rains have returned?  As explained last spring, a single wet winter after a dry period can replenish snowpack, soil moisture, and surface water reservoirs, but groundwater basins may take many years or even decades to recover.

An average or wet winter may make up for water level losses of one dry year, but often not much more.  Also, the amount and location of groundwater level recovery varies with other factors such as the local reliance on groundwater or chronic overdraft.

At the end of the most recent drought, the near average 2016 precipitation in Northern California helped stabilize groundwater levels, and some areas saw groundwater level recovery. The extremely wet winter in 2017 expanded groundwater recovery to most of California (Figure 2).

Throughout California, the wet winter of 2017 refilled groundwater storage leading to higher water levels in spring of 2017, when compared to spring 2016. Source: DWR 2017

In many areas with significant groundwater pumping, therefore, two average to wet years are not enough for groundwater to recover from several dry or drought years.  For example, the change in groundwater levels over the last 5 years (Figure 3) or the past 10 or 17 years (Figure 4) shows that groundwater aquifer conditions can have a long memory.

Figure 3: In most of California’s groundwater basins, the wet winter of 2017 did not refill groundwater storage to where it was before the 2012-2016 drought, in the spring of 2012. Source: DWR 2017

Figure 4: For most of California, 12 of the past 18 winters (and 7-8 of the past 11 winters) were below average or dry. As groundwater levels in most basins need one average or wet winter to recover from one below average or dry year, many areas are several average to wet years short of reaching water levels observed in spring 2000. Source: DWR.

The lack of groundwater level recovery is partly from persistent below-average precipitation in the past 20 years. This can be seen by comparing the long-term change in groundwater levels with the cumulative deviation from average (CDFM) statewide rainfall (Figure 5). The recent twenty-year sequence of more below-average years than average or wet years appears as a decline in the orange line in Figure 5. For comparison, DWR’s groundwater data and tools website includes groundwater level change maps of the difference in groundwater elevations over various time periods, with pie charts indicating the regional and statewide percent of wells increasing, decreasing, or staying relatively neutral (e.g., Figures 2 and 3). We can construct a groundwater level change index, for example, by subtracting the statewide percent of wells with increasing water levels from the statewide percent of wells with decreasing water levels over a period of time.  A positive number indicates more wells had increased water levels than decreased water levels, while a negative number means more wells have lower water levels than higher water levels.  For example, for Figure 2, the statewide groundwater level change index for 2016-2017 is computed as (30.7%+5.4%-1.0%-6.3%) = +28.8%.

The cumulative deviation from mean statewide precipitation (CDFM) since 1896 (blue line) shows that we reached peak surplus in 1983, 1998 and 2006. But by 2016, after a nearly steady ten-year decline, the deficit reached levels similar to the early 1990s. Note that the CDFM is, by definition, zero at the beginning and end of the averaging period.
Average and wet years can make up for groundwater decline in below-average years: The orange line indicates the difference between the total number of average to wet years to date and the number of below average to dry years to date. If an “average year” includes any year with at least 97% of average precipitation, then an equal number of years have been “average or above” years and “below average or dry” years since 1896 (difference = 0). For 1998 to 2007, five more years were “below average or dry” than “average or above”.

Figure 6 shows this groundwater level change index for 1, 3, 5, and 10 year periods preceding each year from 2012 through 2017. The long-term trends of all four indices – perhaps most so for the 10-year index – are similar to the precipitation trends– as precipitation deficit increases, the groundwater level change index becomes more negative (more and more wells with decreasing water levels). However, as the deficit decreases, fewer wells have decreasing water levels, and more wells have increasing water levels.  This very simple analysis doesn’t account for other factors that can affect long-term changes in groundwater levels, but shows the strong effect of the continued precipitation deficit, relative to 1998.

Figure 6: Comparison of the CDFM (blue) shown in the previous figure with a groundwater level change index that captures relative groundwater level change over the last 1 year, 3 years, 5 years, and 10 years prior to the year indicated at the bottom axis. The 10 year index most closely follows the precipitation CDFM.

What should well owners and operators expect for summer and fall of 2018 if it remains a below average to dry year? This would be like 2007 and 2012.  Both 2007 and 2012 followed wet years with surface reservoirs in good condition, like 2018.  Additionally, 2007 and 2012 had below average precipitation and a thin snowpack.

So, with a below average to dry 2018, groundwater levels would likely decline similarly to 2007 and 2012, but not as drastically as in 2014 or 2015 when additional groundwater pumping occurred from lack of available surface water for irrigation (Figure 7).

Figure 7: Unless April is exceptionally wet, expected water level changes between last fall and this coming fall will be of similar magnitude as between fall of 2011 (following a wet winter) and fall of 2012 (following a relatively dry winter, but with surface water storage carry-over from 2011 to support cities and agricultural irrigation). Source: DWR.

One thing is certain – California’s climate will continue to be variable.  And if the past 20 years are a guide, groundwater levels may have a difficult time recovering.  This reinforces the importance of drought contingency planning, especially for overdrafted groundwater basins and in basins with issues related to declining groundwater levels.

Thomas Harter is a Professor and Associate Director at the Center for Watershed Sciences. Bill Brewster is a Senior Engineering Geologist with the California Department of Water Resources.

 Further reading

CaliforniaWaterblog. Post-drought groundwater in California: Like the economy after a deep “recession,” recovery will be slow.

DWR Drought Page

Spring 2017 Groundwater Level Data Summary

USGS Runoff Estimates for California

DWR Groundwater Information Center Interactive Map Application

DWR Data and Tools Page

Posted in California Water, Groundwater | Tagged , | 2 Comments

Brown is the new gold: Water strategy is starting to pay dividends

by Nan Frobish

Planting orchards in deserts is part of California’s long-term vision for sustainable water management.

Governor Brown has unveiled a sweeping new strategy, “Brown is the New Gold,” to simultaneously make California more robust to drought, secure private water rights, buffer California’s growers against disastrous losses from a looming national trade war, and facilitate a market for environmental water.

“Leadership has not been clever enough, or strong enough, or perhaps visionary enough,” Brown said in a “Meet the Press” interview in 2017. “It takes a certain vision, how the hell do we get out of this? And it takes some political skill at the same time.”

And his vision proved prescient: with a potential trade war threatened between the Trump administration and China, California’s wine, nut, and fruit industries stood to lose billions.

“What’s the next most valuable thing our ag industry has besides the food it provides?” asked Brown. “Water. And someone always needs it.”

And now, Brown’s vision and a quirk in California’s water law have combined to form a system that secures farmer’s water, increases water for fish, and solves the problem using a market strategy – without one penny of government funds.

Brown began quietly laying the groundwork through the end of the recent drought. Reductions in urban water use, largely from the browning of outdoor landscapes, greatly reduced urban water use with minimal economic impact.  This promises to make more water available for agricultural and environmental uses into the future.

During the drought, farmers also faced large cutbacks, and in some cases farmers sold some of their water by browning their fields to that other farms could continue to prosper.

But most may remember the exemption to agriculture during the recent drought – while mandatory reductions were require for cities, farmers were largely left alone. While public outcry railed against what seemed to be a lopsided victory for farmers at the expense of cities and streams, the Brown administration was playing the long game.

Difference in idle Central Valley cropland between 2014 and 2011, relative to the total agricultural land in each region. Prepared by UC Davis Center for Watershed Sciences using information from the Satellite Mapping consortium project of DWR, NASA Ames Research, CSU-Monterrey Bay, USGS and the USDA. 

The key lies in California’s requirement that water right holders can temporarily transfer their right for another purpose or to another user without losing it – but only the portion of their water right that would have been used by the crop they are growing. Some of their water right is used to transport water from the stream to their fields, and the some is used by the crop; only the water used by the crop can be transferred.

So while fruit and nut growers have often been criticized for their profitable, water-demanding crops, their conversion of millions of acres to orchards has reclaimed millions of gallons of water as consumptive use – and thus provided a huge reservoir of tradable water in the event that these commodities take a hit from a global trade war.

Water markets have long been in place in California – the Central Valley Project water users have bought and sold water with each other for decades in ag-to-ag transfers. Ag-to-fish transfers are a newer market, but follow the same principle: a buyer needs water for the environment, a seller has water that might be more profitable as fish flow rather than orchard production, and they agree on a price.

Agricultural water is transferred back to the stream as part of California’s ag-to-fish water market.

“Fruit, nuts, fish,” says San Joaquin grower Lin Stuart. “It’s going to be what it’s going to be. We’ll still make money.”

“You can’t be a superpower and wallow in dysfunctionality,” said Brown. “As the world’s sixth largest economy, California is practically a superpower unto itself. We are going to show the nation what leadership truly looks like, rather than goofing off and averting our gaze.”

Under one provision of the new plan, the State would be able to sell farmers  environmental water if crop prices are high.  During the drought, environmental flow change orders allowed over one million acre feet of Delta outflows to be reduced.  Had this water been sold on the market, it would raise more money for the Delta environment than most water bonds have.

Professor Harold Hotelling of UC Atwater commented, “This scheme will bring market business solutions to all of California’s water problems.”

The State Water Board is considering introducing a WetCoin currency to ease water market transactions.

Nan Frobrish is the Director for Expedition Education at the Center for Watershed Sciences. She recommends first-hand interactions with stream hydraulics.

Further Readings

Hanak, E. and Jezdimirovic, J. Just the Facts: California’s Water Market. Public Policy Institute of California.

UC Davis Center for Watershed Sciences. Drought’s Economic Impact on Agriculture.

Arax, M. A Kingdom from Dust. California Sunday Magazine.

Mitric, J. If China Strikes Back On Tariffs, California Tree Nut Exports Could Take A Hit. Capitol Public Radio.


Posted in April Fools' Day | 7 Comments

California’s Water Data Problems are Symptoms of Inchoate Science and Technical Activities


“The truth is lost when there is too much contention about it.” – Publius Syrus (43 BC)

by Jay Lund

In 2016, California’s legislature passed AB 1755, the Open and Transparent Water Data Act, requiring that State agencies provide water data online, including existing datasets, with open-data protocols for data sharing, transparency, documentation and quality control.  That any legislative body, composed mostly of lawyers, would show interest in the wonkish topic of data and pass legislation on data management, is a testament to the failures of state agencies on the subject.  (Imagine state engineers suggesting changes in legislative rules.)

Efforts are now underway in diverse government agencies and other organizations to make water data available, accessible, and perhaps even organized and better explained.  Alas, if experience is a guide, most improvements from these efforts will be marginal, as they do not address the cause of California’s water data malaise.

Disorganized data is a symptom of disorganized technical work.  California has many agencies and programs involved in water management and regulation, particularly its Department of Water Resources, State Water Resource Control Boards, and Department of Fish and Wildlife.  Each agency has some excellent employees and the state supports some exemplary data and technical resources, particularly regarding floods, often in collaboration with other agencies.  But most of the state’s overall water-related scientific and technical activities are notoriously splintered across programs with independent legal mandates, funding sources, and lines of management, and overall leadership to serve the common good.  Addressing the root disorganization of the state’s technical efforts on water management and regulation is needed for long-term data success.

Fragmentation of the State’s technical activities also has other problems.  The many water accounting systems now hinder development of the common water accounting needed for groundwater recharge and management, water rights enforcement, environmental water management, and water markets.  The splintering of water quality and quantity data collection obscures insights needed for more effective management and hinders quality control within and across agencies.

Water data problems will likely worsen, particularly if unaddressed.  More data are being collected.  As prices for collecting data decrease, we collect much more.  Without organization, more data can add confusion.  The cost and controversies of making sense and developing insights from data is increasing.  Without synthesis, each side chooses the data and interpretations it wishes for.

Data will always be frustrating, even if we manage it well.  Good management and use of data will reveal sometimes unwanted insights and unrealized gaps and needs.  Good data management also raises demands for new analysis and quality control.  The more we know, the more we want to know and make sure of.  This is a price of progress.

California’s water challenges are leading to a more integrated water management, which needs to be supported by more integrated technical programs across the many state agencies and programs.  Implementing the Sustainable Groundwater Management Act will be excruciating for water users and all agencies without a common water accounting framework and common technical information (including recognized models and data).  The effectiveness of environmental flows will continue to be clouded and undermined without coordinated data collection, management, and analysis.  And water rights will be less secure, less marketable, and often unenforceable without more solid water accounting.

The problem is not lack of legislation or even (mostly) lack of money.  Local and regional water agencies already collect and manage immense amounts of water data, which can better contribute to a common understanding of California’s water.  State agencies need a more common scientific and technical program for water management and regulation, providing common support across agency boundaries.

The progress report on California Department of Water Resources’ (DWR’s) implementation of Assembly Bill 1755 contains many good things and is a step in the right direction.  However, these steps will not progress far or fast without a broader and more profound vision for more effective state technical water work, across agencies, extending well beyond DWR.  Integrated water management requires integrated scientific and technical work across the many state, local, and federal water data and technical efforts.

A few specific thoughts on the document:

  1. Funding for data management is as fundamental as funding personnel and personnel records, and should be part of every agency’s financial plan. That the report seeks separate funding for data management misses how fundamental data management is for the success of the state’s water management enterprise.
  2. A test bed and use cases are important, but it is also important not to stake too much on the success of the details of this narrow effort. Technology development often outstrips state software development.  Technological progress in this field can be both an opportunity (if we are prepared for it) and a problem (if we are not).  This is a rapidly-changing field.
  3. A “federated” approach to water data is needed.  The state’s most successful data and technical efforts are usually joint efforts across state and federal agencies, such as CNRFC, or joint efforts across state, federal, and local agencies for data collection. To be effective and not bog down in bureaucracy, a federated approach will need consistent accountability, motivation, and resources.  The most effective water data management efforts (CDEC and CNRFC) are motivated by flood problems, which must respond quickly to serve a wide range of users or create violent consequences.
  4. An improved institutional setting for data management might support improved technical information and coordination overall. Each state agency might develop a routine data management policy for its major functions, so that these data and functions might be more transparent and more easily coordinated across agencies.
  5. In data management, the best can be the enemy of the good. Trying to address too many issues too soon usually leads to collapse. Success will be frustratingly slow.
  6. One activity that would provide immediate and lasting service to all state and local agencies, as well as the public, would be on-line archiving of all reports done by or for state agencies. Maven’s water library is a prototype of such a system. The University of California library system is another suitable steward for such a system.  Any state project or decision process could archive analyses and reports with an automated system where agency staff and consultants could enter, catalog, upload, and archive documents into the library.  State agencies and programs often place documents on the web, but these can quickly become a dystopia of broken links.

The Department of Water Resources is accepting comments on its Progress Report – Implementing the Open and Transparent Water Data Act with Initial Draft Strategic Plan and Preliminary Protocols until March 30, 2018.

Jay Lund is a Professor of Civil and Environmental Engineering at the University of California – Davis, where he is also Director for its Center for Watershed Sciences. He enjoys data, and hungers for mostly better.

Further reading

California Legislative Information (2016), AB-1755 The Open and Transparent Water Data Act,

California Department of Water Resources, California Data Exchange Center (CDEC),

James, K. (2016), “California’s New Water Data Law Will Have Far-Reaching Benefits,” Water Deeply, 11 October.

Lund, J. (2016), How much water was pumped from the Delta’s Banks Pumping Plant? A mystery,, Posted on

Maven’s Notebook, California Water Library,

Mount, J. (2018), Advice on Voluntary Settlements for California’s Bay-Delta Water Quality Control Plan Part 3: Science for Ecosystem Management,, Posted on February 27, 2018.

National Oceanographic and Atmospheric Administration (NOAA), California-Nevada River Forecast Center (CNRFC),

UC Davis Center for Water-Energy Efficiency, work on data analytics




Posted in California Water, Planning and Management, Tools | Tagged | 2 Comments

How engineers see the water glass in California


Engineering a water glass at 50 percent. Source:

It looks like 2018 will be a dry year, with snowpack about 50%.  How do engineers see the water glass in California?  Mostly the same as they did six years ago in the original version of this post, but we’ve added a few more perspectives.

By Jay R. Lund

Depending on your outlook, the proverbial glass of water is either half full or half empty. Not so for engineers in California.

Civil engineer: The glass is too big.

Flood control engineer: The glass should be 50 percent bigger.

Army Corps levee engineer: The glass should be 50 percent thicker.

Mexicali Valley water engineer: Your leaky glass is my water supply.

Delta levee engineer: Why is water rising on the outside of my glass?

Dutch levee engineer: This water should be kept in a pitcher.

Southern California water engineer: Can we get another pitcher?

Northern California water engineer: Who took half my water?

California Water Commission engineer: Would a bigger glass provide public benefits?

Tulare Basin water engineer: I’m saving that storage to capture floods for recharge.

USBR CVP or NOAA engineer: Is that water cold?

Consulting engineer: How much water would you like?

Environmental engineer: I wouldn’t drink that.

Water reuse engineer: Someone else drank from this glass.

Groundwater engineer: Can I get a longer straw?

Academic engineer: I don’t have a glass or any water, but I’ll tell you what to do with yours.

Lawyers, NGOs, managers, regulators, and elected officials also seem to have different views of glasses at 50% of their capacity.  We can start a collection of these perspectives.

Jay Lund is a professor of civil and environmental engineering and director of the Center for Watershed Sciences at UC Davis.

Further reading

Munroe, Randall. Glass Half Empty.

Posted in Uncategorized | 3 Comments

Is Ecosystem-Based Management Legal for the Sacramento-San Joaquin Delta?

by Brian Gray (PPIC Water Policy Center), William Stelle (former NOAA Fisheries West Coast Administrator), and Leon Szeptycki (Stanford University, Water in the West)*

The Sacramento-San Joaquin Delta. (Photo credit: Carson Jeffres)


In a recent three-part series posted on this website, a group of independent experts (including one of the authors here) proposed new ways to manage the Sacramento-San Joaquin Delta ecosystem. The purpose of the recommendations is to inform negotiations on the revised Bay-Delta Water Quality Control Plan, which will set new water quality and flow requirements for the Delta and its tributaries.

These experts urged the State Water Board and negotiating parties to: (1) take an integrated approach to the Delta to improve food web productivity and habitat, while reducing harmful algal blooms; (2) coordinate management of freshwater flows, tidal energy, and landscape changes in the North Delta and Suisun Marsh to improve ecosystem function; and (3) develop a robust, well-funded independent science program to guide implementation and assessment of the water quality plan.

The experts note that populations of native fish species listed under the state and federal endangered species acts are so low that they are no longer reliable indicators of Delta conditions. They recommend shifting away from an emphasis on managing the Delta for these listed species. And they outline an ecosystem-based approach that would improve conditions for a wide range of terrestrial, wetland, and aquatic plants and animals—including listed fish species—as well as for human uses of the Delta’s water and lands.

These recommendations are intriguing, especially in light of growing consensus that the current approach to water quality and species protection in the Delta is failing to meet legal and policy objectives. But would management based on the proposed policies be legal?

Ecosystem-Based Management

An ecosystem-based approach to the Delta would differ in several important respects from the existing regulatory regime. Current regulations rely heavily on minimum flow and water quality standards, which are often met by releases from upstream reservoirs. These regulations also impose a variety of constraints on Central Valley Project (CVP) and State Water Project (SWP) operations—including seasonal restrictions on water exports from the south Delta—to minimize reverse flows and prevent dislocation and entrainment of fish.

The proposed approach calls for more flexible deployment of releases from upstream reservoirs to improve aquatic habitat, along with landscape changes to enhance habitat benefits from managed freshwater and tidal flows. The proposal also advocates focusing conservation and recovery actions on an arc of habitat from the Yolo Bypass through the North Delta and into Suisun Marsh (the “North Delta Arc”), which has been less altered by human interventions and is linked by the Sacramento River.  This area has a greater likelihood of producing significant, near-term ecological improvements compared with conservation actions elsewhere in the Delta. The proposal also would alter the current strategy of using large volumes of freshwater outflow to manage salinity in the Delta and Suisun Bay, choosing instead a geographically targeted approach to the application of freshwater flows.

Although it would represent a marked change from existing regulatory policy, an ecosystem-based strategy would be consistent with the water quality laws and the endangered species acts.

The Water Quality Laws

California’s Porter-Cologne Act implements the federal Clean Water Act and establishes independent state standards for water quality. It requires the State Water Board to set water quality standards that provide “reasonable protection” for an array of beneficial uses of the waters of the Delta ecosystem, including fish and wildlife and water supply. The courts have held that the Board has broad authority to determine what water quality criteria are reasonable and appropriate in light of competing demands on the resource, as long as its decision is supported by substantial evidence in the administrative record.

The Porter-Cologne Act thus grants the Board significant discretion to choose how best to deploy the freshwater available in the Delta. For example, if the Board concludes that the North Delta Arc is the most productive habitat for conserving and recovering protected species, then it would have authority to set water quality standards (including targeted flow requirements) that make this a priority region. If the Board is also persuaded that the central and south Delta are now unproductive and inhospitable habitat for native fish species, it could adjust salinity and flow standards accordingly.

In short, because of the multifaceted and flexible authority vested in it by the water quality laws, there is no significant legal impediment for the State Water Board to follow an ecosystem-based approach in revising its water quality standards for today’s Delta.

The Endangered Species Acts

The federal and state endangered species acts pose more difficult questions because they contain more rigid directives than do the water quality laws. Rather than setting standards to accommodate a variety of beneficial uses, these laws categorically prohibit the unauthorized “taking” of any protected fish. The federal statute also requires all federal agencies to ensure that their actions are not likely to jeopardize the continued existence of any listed species or adversely modify their critical habitat. Takings that are “incidental” to otherwise lawful activities—including water diversions and other water project operations—may be authorized by incidental take statements in biological opinions or by incidental take permits for non-federal activities. Both laws require the impacts of authorized takings to be “minimized,” and the state statute requires that they also be “fully mitigated.”

These laws govern water management in the Delta ecosystem principally as applied to the coordinated operations of the CVP and SWP, which must comply with a series of conditions set forth in biological opinions issued by the U.S. Fish and Wildlife Service (USFWS) for Delta smelt and by the National Marine Fisheries Service (NMFS) for anadromous species (salmonids and green sturgeon). The California Department of Fish and Wildlife (CDFW) plays a complementary role. Its principal regulatory authority in the Delta is through the longfin smelt incidental take permit issued to the SWP.

Legal Questions

The proposed ecosystem management approach raises several key legal questions to which we provide brief answers:

  • Is an ecosystem-based approach to water quality and species protection consistent with the federal and state endangered species acts?

Yes. Although the focus of the endangered species acts is on individual species and their critical habitat, there is nothing in the statutes that would preclude the fish agencies from adopting a more holistic and integrated approach—if the best scientific evidence supports the decision that the ecosystem objectives would be an effective means of fulfilling the no jeopardy/adverse habitat modification standards, as well as the mitigation requirements associated with the incidental take of each listed species.

Indeed, this legal question can be framed in a relatively simple way: What are good scientific metrics for predicting and assessing ecosystem functions (e.g., food web productivity) on which each species relies for its survival and recovery, and are these better expressed as ecological system metrics, rather than through the salinity, flow, and temperature metrics that are currently employed? If the ecosystem approach would be a better way to protect and enhance the biological requirements of each listed species, the fish agencies could approve it under the conventional consultation and incidental take regulatory processes.

  • Could the federal fish agencies revise the biological opinions for CVP/SWP operations to recognize the proposed focus on a North Delta Arc of critical habitat?

Yes. If the agencies conclude that creation of a North Delta Arc of habitat would promote the applicable conservation standards for each of the federally listed species, they would have authority to incorporate this strategy into the biological opinions. As noted above, these could include changes in upstream storage and release requirements to provide targeted flows into the Sutter and Yolo Bypasses, as well as other tidal sloughs and channels, to improve food webs and aquatic habitat.

  • Could the federal agencies revise the biological opinions to recognize a geographically specialized Delta ecosystem that reduces the emphasis on the central and south Delta as critical habitat for some species?

Yes. The federal endangered species act does not require conservation and recovery of listed species throughout their entire range of existing or potential habitat. It also affords the fish agencies considerable flexibility in setting priorities for habitat types and locations—if these conservation strategies would satisfy the no jeopardy/critical habitat directives for each listed species.

Therefore, if the best scientific evidence supports the conclusion that the central and south portions of the Delta are irreparably degraded and that the North Delta Arc is now the most promising habitat for the Delta smelt, the USFWS could adopt geographic specialization as a conservation strategy. This would be accompanied by changes in the critical habitat designation for the smelt, as well as adjustments in the incidental take limitations for the CVP and SWP south Delta pumps to account for this change in focus.

Similarly, NMFS could conclude (also based on the best available science) that the most promising habitat for Sacramento River salmonids is the North Delta Arc. Based on this determination, it too could shift the focus of its conservation and recovery directives to that region. The salmonid biological opinion also would have to include measures to promote passage of salmon and steelhead in the central and south Delta and lower San Joaquin River. As there is no scientific consensus on this subject, we recommend that NMFS—in cooperation with CDFW and the State Water Board—convene a small independent panel of creative scientists and engineers to evaluate the options.

  • Could the California Department of Fish and Wildlife revise the State Water Project’s incidental take permit for longfin smelt to recognize a specialized Delta ecosystem?

Yes. Although the longfin smelt once inhabited much of the Delta, its current population exists primarily in San Francisco Bay. As with federal law, the California Endangered Species Act does not require conservation and recovery of listed species throughout the full extent of their habitat, and it grants CDFW discretion to create priority habitat characteristics and locations. The department therefore would have authority to make the North Delta Arc (which once was important spawning habitat for the smelt) the focus of its conservation and recovery efforts.

Longfin smelt are anadromous and depend on freshwater and tidal flows in the Delta and Carquinez Strait. CDFW would have to ensure that the North Delta Arc conservation and recovery strategy would provide conditions that enable the fish to migrate between their freshwater and more saline habitats.

In addition, in revising the SWP’s incidental take permit, the department must determine that the North Delta habitat improvements would “fully mitigate” any adverse effects of the change in policy. Restoration and long-term enhancement of intertidal and sub-tidal wetlands in the North Delta is already part of the mitigation requirements of the SWP’s incidental take permit. If necessary to offset any risks posed to the smelt from the new habitat strategy, CDFW could require the acquisition and management of additional mitigation acreage.

Concluding Thoughts

Ecosystem-based management in the Delta may be a more efficient and effective means of implementing the water quality laws and endangered species acts than the current regulatory regime. Whether this is true will depend on the responses of the ecosystem and the fishes that inhabit it to the combination of targeted freshwater flows, tidal energy management, and landscape changes that would be concentrated along the North Delta Arc.

To test this new strategy, regulators, water managers, and environmental advocates must be willing to assume the risk of moving away from entrenched policies that have largely failed to achieve their objectives. The judgment whether the new approach is the “best available science”—and therefore may serve as the foundation for a revised water quality control plan and new biological opinions—rests with the regulators. We can simply say that there is nothing in state or federal law that would preclude such a decision.

More importantly, the strategy proposed in the earlier blog posts illustrates a foundational—but often neglected—principle of aquatic ecosystem management: Protection of water quality and conservation of species are one in the same, and neither can be achieved without the other. Perhaps the greatest contribution of the new Delta science will be to encourage the State Water Board and the fish agencies to work together to devise truly integrated standards for today’s novel Delta ecosystem.

* With contributions and insights on the intersections between law and science from Peter Moyle and Jay Lund (UC Davis) and Jeff Mount and Ellen Hanak (PPIC Water Policy Center).

 Further Reading

Gartrell, Greg, and Brian Gray. 2017. A Brief Review of Regulatory Assignment of Water in the Sacramento–San Joaquin Delta. Public Policy Institute of California.

Gore, James, Brian Kennedy, Ronald Kneib, Nancy Monsen, John Van Sickle, Desiree Tullos. 2018Independent Review Panel (IRP) Report for the 2017 Long-term Operations Biological Opinions (LOBO) Biennial Science Review: Report to the Delta Science Program. Delta Stewardship Council and Delta Independent Science Program.

Mount, Jeffrey. 2018a. “Advice on Voluntary Settlements for California’s Bay-Delta Water Quality Control Plan Part 1: Addressing a Manageable Suite of Ecosystem Problems.California WaterBlog, Feb. 13.

Mount, Jeffrey. 2018b. “Advice on Voluntary Settlements for California’s Bay-Delta Water Quality Control Plan Part 2: Recommended Actions to Improve Ecological Function in the Delta.” California WaterBlog, Feb. 21.

Mount, Jeffrey. 2018c. “Advice on Voluntary Settlements for California’s Bay-Delta Water Quality Control Plan Part 3: Science for Ecosystem Management.” California WaterBlog, Feb. 27.

Moyle, Peter, William Bennett, John Durand, William Fleenor, Brian Gray, Ellen Hanak, Jay Lund, and Jeffrey Mount. 2012. Where the Wild Things Aren’t: Making the Delta a Better Place for Native Species. Public Policy Institute of California.

Wondolleck, Julia, and Steven Yaffe. 2017. Marine Ecosystem-Based Management in Practice: Different Pathways, Common Lessons. Island Press.

Posted in California Water, Delta, Sacramento-San Joaquin Delta | Tagged , | 4 Comments

Back to Dry – Get Organized and Prepared for Drought Again

PLOT_ESI 3-3-18

Accumulated precipitation for northern California, 35% less than average and one third of 2017!

by Jay Lund

Despite this week’s rain and snow, California is back to dry conditions again after a very wet 2017.  With about four weeks left in the normal wet season, the Sacramento Valley is at about 65% of average precipitation (less than 1/3 of last year’s precipitation).  The southern Central Valley has less than 50% of average precipitation and southern California is still drier.  Snowpack is much less, at 37% statewide.  Surface reservoirs, which almost all refilled and spilled in record-wet 2017, are now at 98% of average for this time of year, and will fall quickly as there is well-below-normal snowpack to melt.  The large water projects are expecting to make some water deliveries, but much less than last year.  Groundwater, California’s largest reservoir, is in mostly good shape in northern California, but in the drier parts of California has not nearly refilled the additional pumping from the last drought.  Even if March is very wet, 2018 almost certainly will be dry.

Does this mean California is back to drought?  Some, but mostly not yet.  Drought comes on fast for some areas and more slowly for others.  California’s forests will likely experience drought this year.  Soil moisture and snowpack are the forests’ only reservoirs, and these deplete fast.  Having lost over 100 million trees from the still-recent previous drought, there will be plenty of dead wood and dry conditions for wildfires this year.  Aquatic ecosystems also can be expected to suffer in a dry year, especially as there has been little recovery of Delta Smelt and salmon from the recent drought.

Most cities and agriculture should be able to weather this year’s dryness with water stored in reservoirs and some additional groundwater use.  Some areas will be worse affected, however.  Southern Central Valley agriculture is slated to receive substantial surface water delivery cut-backs compared with last year.

A series of dry years leads to more widespread and deeper effects of drought.  Shallow rural wells are increasingly affected as dry conditions and the depletion of surface reservoirs leads to more groundwater pumping.  More groundwater pumping will make it harder for some regions to comply with the state’s new Sustainable Groundwater Management Act.  The drawdown of reservoirs also leads to problems maintaining flows and cold temperatures for salmon and Delta outflows.  Damages to ecosystems accumulate with additional dry years.

Areas prepared for drought suffer much less than areas with little or ineffective preparations.  But all areas suffer some.  Implementation of the Sustainable Groundwater Management Act is essential for rural areas to prepare for drought, as most agriculture and Central Valley water supplies will always depend on groundwater storage to get through long droughts.  Preparation is hardest for areas that lack organization and regular funding, such as small rural water systems and ecosystem management.  These are among the greatest challenges.

Now is the time for state and local agencies to prepare for drought, before a drought is declared.  Most cities and irrigation districts are now well-practiced for drought, and should now have better plans.  Waterfowl managers were fairly well-organized for the previous drought and introduced some useful innovations.  However, fish and aquatic ecosystem management was largely unprepared for drought, and urgently need plans and preparations for drought. Many water and environmental managers are likely to need drought plans this year.  Even in the best cases, they will need drought plans and preparations all too soon.

Drought and dry years have always accelerated innovation in California’s water management.  Given our climate, California will always have water problems, and opportunities to improve.  Now is a good time to prepare for drought, and to prepare to make other long-term improvements.

Jay Lund is the Director of the UC Davis Center for Watershed Sciences

Further Reading

The mighty California Data Exchange Center,  (Showing that some parts of California government do data fairly well – although we would always like more and better.)

Posted in California Water, Drought, Planning and Management | Tagged | 2 Comments

Advice on Voluntary Settlements for California’s Bay-Delta Water Quality Control Plan Part 3: Science for Ecosystem Management

by Jeffrey Mount, PPIC Water Policy Center*

The Delta. Photo credit: Carson Jeffres


Improving Delta ecosystem functions under the State Water Board’s proposed Bay-Delta Water Quality Control Plan will require a complex series of changes to water and land management—and a strong science program to guide actions. This science effort will need to go well beyond current Delta science programs in scope, authorities, and funding. The most promising approach is to expand the existing Delta Science Program and grant it the authority and responsibility to support the plan. As part of this effort, parties engaged in the Delta should create a Delta Science Joint Powers Authority (JPA) to better pool and administer science resources to be used by the Delta Science Program. The JPA also would be a forum for agencies, water users, and other stakeholders to develop consensus and collaborations on science-based management.


The State Water Board is updating its Water Quality Control Plan for the Sacramento-San Joaquin Delta. Multiple parties that would be affected by this plan are seeking to negotiate voluntary settlement agreements for the Board to consider.  In two previous posts, a group of us* have suggested that the Board and negotiating parties take a new approach to resolving some of the Delta’s ecological and water supply problems. The first post calls for integration of freshwater flows with tide and landscape management to improve food web productivity, maximize habitat for desirable plants and animals, and reduce the impacts of harmful algal blooms. The second post describes a suite of actions to meet these objectives.

This approach cannot succeed without a strong science program that is well-funded, authoritative, and useful. Most important, this science program must go beyond meeting the traditional interests of specific state and federal agencies and integrate science to meet broader objectives. It must also be an integral part of any adaptive management program. In this blog post we propose a science effort to inform and assess the implementation of the Water Quality Control Plan.

Science in the Delta Today

The San Francisco Estuary, including the Delta, is one of the most studied in the world (Cloern and Jassby 2012, Healey et al. 2016).  Science and monitoring is done by many state and federal agencies, water utilities, water user organizations, universities, stakeholder groups, and a large network of consultants (summarized in Hanak et al. 2013 and Gray et al. 2013). Many reviews of the science enterprise in the Delta have recommended reforms. Two particularly useful reviews are by the National Research Council (2012) and the Delta Independent Science Board (DISB 2016, Weins et al. 2017). Several persistent themes from these reviews inform the proposals made here. These include:

  • Conflicting agency goals lead to fragmentation of scientific efforts (Lund and Moyle 2013);
  • Divergence among preferred actions of different organizations — combined with fragmented science administration — leads to advocacy-based or “combat” science, pitting different organizations against each other in their scientific efforts;
  • The lack of reliable funding — and the inability to deploy it quickly — hampers the ability to conduct innovative science and monitoring, respond to new opportunities and information, and sustain vital long-term investigations.

Since the publication of the 2012 National Research Council report, there have been efforts to improve Delta science, principally through cooperation and collaboration among the many current efforts. But as the NRC report pointed out, “collaboration does not equal integration.” While these efforts have improved the quality of the science, they are not sufficient to support the integrated, ecosystem-based management program recommended in our previous posts.

Matching Science with Management Goals and Objectives

In our view, no single state agency has the capacity or authority to guide the implementation of the ecosystem management actions needed over the next 15 years. In addition, science funding has been unreliably based on a boom-bust cycle of state bonds and other sources; it has been unable to support the sustained research needed to inform and improve management. However, we believe the building blocks for an effective science program exist. The core of our proposal is to elevate the existing Delta Science Program (DSP) by granting it responsibility and resources to guide the science needed to implement the Water Quality Control Plan.

The Delta Science Program was established by the 2009 Delta Reform Act. Its mission is to provide the best available science for decision making in the estuary and watershed. The DSP answers to the Delta Stewardship Council, which appoints its lead scientist and approves the program’s budget. The program also houses the Delta Independent Science Board—a group of distinguished scientists and engineers who advise on scientific issues. At present, the DSP primarily tries to coordinate the many disparate science activities in the Delta, develop syntheses on important topics, and run modest grant and fellowship programs.

Although the DSP is structured to do just the kind of integrated science needed to meet the needs of the Water Quality Control Plan, it lacks the necessary budget and authority over the science agenda. We propose expanding its mission and finding creative ways to grant it the financial and institutional capacity to succeed.

The New Delta Science Program and Delta Science Joint Powers Authority

The Delta Science Program should be given resources and decision-making authority to:

  • Work with agencies, water users, and other stakeholders to develop a science action plan to meet the Water Quality Control Plan’s ecosystem-based objectives and, where possible, the broader science needs of state and federal agencies and stakeholders;
  • Build capacity to project outcomes of flow-tide-landscape investments with integrated hydrodynamic, ecologic, and economic models supported by data collection networks;
  • Coordinate protocols and data for monitoring in the estuary and the watershed to inform the Water Quality Control Plan;
  • Implement and oversee a science program that can guide management actions as experiments and assess outcomes and performance measures;
  • Build trust and promote consensus on the science used to inform decision making (recognizing that there will never be consensus on the decisions themselves).

The DSP has a good foundation to take on this task. Its 2016 Delta Science Plan and 2017-21 Delta Science Action Agenda cover many of the proposals in our earlier posts, and could readily be adapted to organize the science needed to guide implementation of the Water Quality Control Plan. In addition, the DSP already has a governance structure that provides both administrative oversight (by the Delta Stewardship Council) and scientific oversight (by the Delta Independent Science Board and review panels).

Placing the DSP in charge of science for the Water Quality Control Plan is insufficient, however, given both funding and institutional constraints. To overcome these hurdles, we suggest that the DSP be the core of a new Delta Science Joint Powers Authority (JPA). This JPA would be modeled, in part, after a successful water quality research effort in Southern California. The Southern California Coastal Water Research Program (SCCWRP) is a JPA that unites sanitation and stormwater agencies with water-quality regulating agencies. Together, these parties develop and fund a common scientific effort to support management and monitoring decisions on stormwater and wastewater. This program—which has also benefitted from excellent leadership—shows how to develop high quality, useful, and consensual science support for policy and management decisions.

Like SCCWRP, the Delta Science JPA would be funded and overseen by a group of regulated and regulatory entities and other parties. It would be chaired by the DSC, with a science program led by the DSP’s lead scientist. State and local public agencies would be signatories to this effort and contribute financial support or personnel. Federal agencies cannot sign JPA agreements, but they can contribute resources and serve on the JPA board. The JPA board can also include non-governmental stakeholder representatives, such as environmental non-profits. In this way, the parties affected by and overseeing the Water Quality Control Plan would have an opportunity to pool resources and build consensus on a science agenda and integrate scientific findings and actions.

The JPA structure provides a better way to fund scientific research and experimentation than is currently available to the DSP or other state agencies. JPAs can exercise authorities granted to any signatory agency.  Because local agencies generally have more flexibility to administer funds than state agencies, the JPA will be able to write contracts to support research and monitoring activities more quickly (days instead of many months), and with less overhead.  At present, difficulties in securing timely contracts from state and federal funders present a hurdle to science in the Delta and lead to missed opportunities for research by agencies, universities, non-profits, and private consultants.

We estimate that $20 to $30 million annually is needed to fund this science program.  (This is in addition to the current DSP budget of approximately $10 million, and does not count planned restoration efforts or monitoring activities currently being conducted by agencies.) Without a budget of this scale, there is little hope for a successful, collaborative, science-based ecological management program in the Delta. Funding sources could include pooled contributions from JPA members, contracts for research, appropriations from the state General Fund, and small fees on the use of water originating in the watershed and the discharge of pollutants into waterways both upstream of and within the estuary. For example, a $1/acre-foot fee on water use would generate more than $20 million annually.

In conclusion, we believe this proposed approach—elevating the Delta Science Program and anchoring it within a new Joint Powers Authority—is a practical and effective way to develop the scientific support needed to guide, evaluate, and adapt implementation of the Water Quality Control Plan. It builds on existing institutions while establishing a way to build consensus around a science agenda, pool and use resources more efficiently, and tailor a science program to meet the needs of an integrated, ecosystem-based approach to improving ecosystem conditions in the Delta.

*This blog post summarizes some of the ideas generated by an informal group of experts who have met several times to explore concepts for better management of the Delta. Group members include (in alphabetical order): Jon Burau (US Geological Survey [USGS]), Jim Cloern (USGS), John Durand (UC Davis), Greg Gartrell (consulting engineer), Brian Gray (PPIC), Ellen Hanak (PPIC), Carson Jeffres (UC Davis), Wim Kimmerer (San Francisco State University), Jay Lund (UC Davis), Jeffrey Mount (PPIC), and Peter Moyle (UC Davis).

Further Reading

Cloern, J., and A. Jassby. 2012. “Drivers of Change in Estuarine-Coastal Ecosystems: Discoveries from Four Decades of Study in San Francisco Bay,” Reviews in Geophysics. 50.

Delta ISB (Delta Independent Science Board). 2017.  Improving Adaptive Management in the Sacramento-San Joaquin Delta.  Delta Stewardship Council.

Delta Science Program. 2016. Delta Science Plan: One Delta, One Science.  Delta Stewardship Council.

Delta Science Program. 2017. Science Action Agenda: A Collaborative Road Map for Delta Science. Delta Stewardship Council.

Gray, B., B. Thompson, E. Hanak, J. Lund, J. Mount. 2013. Integrated Management of Delta Stressors: Institutional and Legal Options.  Public Policy Institute of California.

Hanak, E., J. Lund, J. Durand, W. Fleenor, B. Gray, J. Medellin-Azuara, J. Mount, P. Moyle, C. Phillips, B. Thompson.  2013.  Stress Relief: Prescriptions for a Healthier Delta EcosystemPublic Policy Institute of California.

Healey, M., P. Goodwin, P., M. Dettinger, and R. Norgaard. 2016. The State of Bay–Delta Science 2016: An Introduction. San Francisco Estuary and Watershed Sci. 14

Lund, J. and Moyle, P. 2013. “Adaptive Management and Science for the Delta Ecosystem.” San Francisco Estuary and Watershed Sci. 11.

NRC (National Research Council). 2012.  Sustainable Water and Environmental Management in the California Bay-Delta.  National Academies Press.

Weins, J., et al. 2017. “Facilitating Adaptive Management in California’s Sacramento–San Joaquin Delta.” San Francisco Estuary and Watershed Sci. 15.

Posted in California Water, Delta, Planning and Management, Sacramento-San Joaquin Delta | Tagged , , , , , , , , , , | 6 Comments

Advice on Voluntary Settlements for California’s Bay-Delta Water Quality Control Plan Part 2: Recommended Actions to Improve Ecological Function in the Delta

by Jeffrey Mount, PPIC Water Policy Center*

The Sacramento-San Joaquin Delta.


By strategically linking freshwater flow releases with the management of tidal energy and investments in landscape changes in the Delta, it is possible to improve ecological food webs and habitat for native species and reduce the effects of pollutants. Projects to address these problems should be concentrated in the North Delta and Suisun Marsh, and can be completed within 15 years. These include habitat improvements on flood bypasses, terminal channels, shallow open-water habitat, river-tide transition zones, and tidal marshlands, along with strategies for reducing harmful algal blooms. This integrated, ecosystem-based approach—in which freshwater flows, tides, and landscapes are managed together—is preferable to current approaches that manage them mostly in isolation from one another, and for a few species of fish.


The State Water Board is preparing a new Bay-Delta Water Quality Control Plan. Parties affected by this plan are attempting to negotiate voluntary settlement agreements for the Board to consider. A group of us—experts on the Delta and not part of any negotiations or representing any interested parties*—have come up with a series of recommendations to help inform these negotiations. This is the second in a series of three blog posts that reflect our discussions and conclusions. In our previous post, we recommended that negotiating parties and the Board identify and focus on a set of ecological goals for the Sacramento-San Joaquin Delta that could be achieved over the next 15 years. That post also lays out our view of the problems facing the Delta and the tools that can be used to better manage it.  Here we recommend near-term actions with the greatest likelihood of achieving significant and measurable progress in improving ecosystem conditions.

These recommendations are based principally on the professional judgment of the group, guided by a set of constraints on Delta management that will need to be taken into account (see text box). Many of the actions will be familiar to those working on ecosystem issues in the Delta.

Management Options to Improve Delta Ecosystem Conditions

The Delta and its watershed face many different environmental problems, and multiple tools are available to address them. There are three general management options (all include a commitment to improve water quality through management of pollutants):

  1. Focus on flow volumes: Emphasize allocation of freshwater flows to the ecosystem, with significant increases in outflow from the Delta into San Francisco Bay and the ocean.
  2. Focus on landscape management: Improve habitat through landscape management with no major changes in the current allocation of freshwater flows.
  3. Use a portfolio of actions: Increase flexibility in the timing and magnitude of freshwater flows and link these to landscape modifications that increase habitat benefits and take advantage of tidal energy (described below).

All three approaches have scientific merits and uncertainties; they also present different social and economic trade-offs. The first—significant increases in Delta outflows—is based on the historical connection between cool, wet years and improved population counts of some species, including pelagic fishes. This relationship is no longer as clear, however, particularly for Delta smelt (see the text box). To fully test this approach the Board would have to re-allocate very large amounts of water to outflow, because modest, incremental changes in outflow are unlikely to result in substantial changes in Delta conditions.  This would have large impacts on available water supplies.

The second approach—relying principally on landscape changes to improve conditions—seeks to reverse some of the extensive losses in habitat caused by land reclamation, channelization, and flood control projects.  Like the high outflow approach, this too has merit. But it ignores the importance of flow timing and magnitude to ecosystem functions and the life-history requirements of desirable plants and animals.

In our view, the third option—a portfolio that includes increased flexibility in how flows are managed, improvements in landscapes, and management of tides—has the highest likelihood of substantially improving ecosystem conditions. This approach also has the best chance of improving our understanding of how to manage the Delta in the future. To be effective, this option will involve reconnecting significant, contiguous areas of land—some currently held in private ownership—to freshwater flows and tides. This will require both the cooperation of Delta landowners and funding to acquire and manage these lands. Changes in flow management could also introduce some new constraints on water availability for human uses. However, by targeting flow releases we expect that this portfolio approach has the potential to use water, land, and financial resources most efficiently to improve ecosystem conditions in the Delta.

We next briefly describe what we mean by management of freshwater flows and tides.  We then outline six project areas for the recommended portfolio approach.

Managing Freshwater Flows

Managing fresh water in conjunction with the landscape and tides will require water users and regulators to shift away from the current approach—which focuses on adhering to minimum instream flow and water quality regulations—toward more flexible management. Flexibility includes allowing for real-time adjustments to hydrologic conditions (for example, to take advantage of pulse flows from storms), experimental flows to test ecological responses to landscape changes, and strategic use of flows to improve water quality. This also involves narrowly targeting flows to improve ecological conditions in specific areas, which increases the efficiency of the use of this water.

Some of us have presented ideas on how to accomplish this using ecosystem water budgets coordinated by designated “ecosystem trustees” (Mount et al. 2017). Regardless of the approach, there is one basic requirement: the ecosystem must have assets to enable managers to adjust the timing of flow releases and diversions. These assets can include a portion of annual flow that can be flexibly used, stored, or traded; water stored in reservoirs or groundwater basins; shares in storage and conveyance capacity; and financial resources to purchase water.

Managing Tides

Tides drive most water movement and mixing in the Delta and the San Francisco estuary. They are vital for connecting nutrients and supporting food webs across tidal marshes and channels, helping to address food limitations within the Delta. The concept of managing tides may be novel to policymakers, but their ecological relevance is grounded in studies showing that ecosystem productivity increases when different habitat types are connected by tidal flows (Cloern 2007).

Tools for managing tides include changing the Delta’s landscape and channels, as well as using gates and barriers. For example, restoring large tracts of tidal marsh will expand the area inundated by tides and dissipate tidal energy, reducing tidal influence elsewhere in the Delta. Gates and barriers can be used to direct tidal flows at the local scale, helping to move food resources (and fish) into or out of specific areas. Landscape changes that do not consider tidal effects can lead to unanticipated or unwanted consequences.

 Six Recommended Flow-Tide-Landscape Projects

To improve food webs, maximize habitat for desirable plants and animals, reduce impacts of algal blooms, and increase understanding of the Delta, we recommend a 15-year commitment to a suite of six linked projects. Five of these projects focus on managing landscapes, tides, and freshwater flows—principally within the North Delta, Suisun Marsh, and the Sacramento River floodplains. The sixth project focuses on building and applying knowledge to reduce the human and environmental health risks of algal blooms.

  • Flood bypasses: Yolo and Sutter Bypasses—the two large flood bypasses on the Sacramento River—have the greatest potential for reestablishing floodplain function in the Central Valley and enriching downstream food webs. Water can be directed through weirs onto floodplains to maximize habitat for migratory fishes (e.g., splittail and juvenile salmon), waterfowl, and wading birds. This requires operable weirs to test and refine management actions, improve ecological outcomes, and allow summer agriculture. This approach also may require pulse flow releases to augment natural flows.
  • Terminal channel systems: The North Delta and Suisun Marsh both have networks of dead-end channels that commonly host abundant native fishes (Moyle et al. 2012, 2014). Tidal mixing within these channels is associated with turbid water—which fish may use to avoid predators—and high food web productivity. In the mixing zone of the Deep Water Ship Channel, for example, Delta smelt and other native fish densities are as high as anywhere in the Delta (Feyrer 2017). Landscape changes and freshwater flow pulses can be used to manage these mixing zones in the North Delta to increase productivity. In Suisun Marsh, the salinity control gates could be used to help meet this objective.
  • Shallow open-water habitat: The Delta has approximately 20 square miles of shallow freshwater habitat, mostly in areas where levee breaches have flooded agricultural lands. Landscape changes may be able to enhance food production in these lake-like areas and transfer it to less productive adjacent channels (Lopez et al 2006). Experiments are needed to test this potential source of productivity.
  • Tidal transition zones: Zones where rivers meet the tides account for a large fraction of juvenile salmon mortality within the Delta (Perry et al. 2018). Seaward of these zones, river flows have little influence on the tides, and correspondingly little impact on mortality. Ongoing research shows that it may be possible to increase juvenile salmon survival in tidal transition zones by restoring marshland and making other landscape changes that reduce the influence of the tides in the North Delta. Strategic, short-duration freshwater flow pulses—coupled with improved channel margin habitat—may also help.
  • Tidal marsh habitat: Marshes, including their networks of branching (“dendritic”) channels, are some of the most productive, high-quality habitats within the Delta and estuary (Moyle et al. 2014).  They also form an important link with upland and wetland areas, promoting the exchange of nutrients and animals essential for this productivity. Creation of new marsh-channel systems is essential and will be most effective in large (1,000+ acre) interconnected areas where they were historically abundant (e.g., in the Cache-Lindsay Slough region and Suisun Marsh; see Robinson et al. 2016). Ongoing research shows that pulses of freshwater flow into Cache Slough have promise for improving habitat and food productivity.
  • Algal blooms: A two-pronged approach is needed to address the problem of harmful algal blooms in the Delta: 1) investigating relationships among flows, water quality, and cyanobacteria blooms; and 2) managing freshwater flows, tides, nutrients, and landscapes to reduce these blooms while promoting productivity for Delta food webs.

Except for the management of harmful algal blooms, all of the projects described above are detailed in some form in numerous state planning and regulatory documents (e.g., Bay-Delta Conservation Plan, Delta Plan, California EcoRestore). The San Francisco Estuary Institute has also produced an excellent summary of opportunities for habitat improvement (Robinson et al. 2016). Our proposed approach emphasizes two overarching recommendations: that priorities be based on geography, and that actions combine—wherever appropriate—the flexible allocation of freshwater flows with the management of tides and landscapes.


Why This Approach Is Better than the Current Path

Federal and state efforts to manage the Delta for ecosystem objectives have been unsuccessful, as indicated by declines in native biodiversity and water quality (Gore et al. 2018). The approach outlined here departs from historical efforts in two ways. First, we propose an integrated approach that considers the complex interaction among tidal and river flows, landscapes, and water quality. Past approaches have failed to consider that the benefits of environmental flows depend on their landscape setting, and that the benefits of landscape changes depend on their hydrologic setting.


Second, we take an ecosystem-based view that includes, but extends beyond, population declines of some native fishes listed under federal and state endangered species laws. The integrated approach seeks to improve Delta ecosystem conditions for a broad range of benefits, including fish and wildlife habitat as well as human uses of the Delta’s lands and water.


In our view, this integrated approach is more likely to achieve positive results and efficient use of resources than the current path. And by focusing on the North Delta and Suisun Marsh, measurable benefits can be achieved within a 15-year time frame. To be successful, however, this approach must be supported by a robust, well-funded, and trusted science program―a subject that will be explored in our next blog post.

*This blog post summarizes some of the ideas generated by an informal group of experts who have met several times to explore concepts for better management of the Delta. Group members include (in alphabetical order): Jon Burau (US Geological Survey [USGS]), Jim Cloern (USGS), John Durand (UC Davis), Greg Gartrell (consulting engineer), Brian Gray (PPIC), Ellen Hanak (PPIC), Carson Jeffres (UC Davis), Wim Kimmerer (San Francisco State University), Jay Lund (UC Davis), Jeffrey Mount (PPIC), and Peter Moyle (UC Davis).

Further Reading:

Cloern, J.E. 2007. “Habitat Connectivity and Ecosystem Productivity: Implications from a Simple Model.” The American Naturalist 169:E21-E33

Gore, J., B. Kennedy, R. Kneib, N. Monsen, J. Van Sickle, D. Tuilos. 2018. Independent Review Panel (IRP) Report for the 2017 Long-term Operations Biological Opinions (LOBO) Biennial Science Review: Report to the Delta Science Program. Delta Stewardship Council and Delta Independent Science Program.

Gray, B., B. Thompson, E. Hanak, J. Lund, and J. Mount. 2013. Integrated Management of Delta Stressors: Institutional and Legal Options, Public Policy Institute of California.

Hanak, E., J. Lund, J. Durand, W. Fleenor, B. Gray, J. Medellín-Azuara, J. Mount, P. Moyle, C. Phillips, and B. Thompson. 2013. Stress Relief: Prescriptions for a Healthier Delta Ecosystem, Public Policy Institute of California.

Lopez, C. B., J. E. Cloern, T. S. Schraga, A. J. Little, L. V. Lucas, J. K. Thompson, and J. R. Burau. 2006. “Ecological Values of Shallow-Water Habitats: Implications for the Restoration of Disturbed ecosystems.” Ecosystems 9:422-440.

Lund, J. and P. Moyle. 2018. Ecological Incentives for Delta Water Exports, January 24.

Mount, J., Gray, B., Chappelle, C., Gartrell, G., Grantham, T., Moyle, P., Seavy, N., Szeptycki, L., Thompson, B. 2017. Managing Freshwater Ecosystems: Lessons from Californias 2012-16 Drought. Public Policy Institute of California.

Moyle, P., W. Bennett, J. Durand, W. Fleenor, B. Gray, E. Hanak, J. Lund, and J. Mount. 2012 Where the Wild Things Aren’t: Making the Delta a Better Place for Native Species, Public Policy Institute of California.

Moyle, P.B., A. D. Manfree, and P. L. Fiedler. 2014. Suisun Marsh: Ecological History and Possible Futures. Berkeley: University of California Press.

Perry, R.W., A.C. Pope, J.G. Romine, P.L. Brandes, J.R. Burau, A.R. Blake, A.J. Ammann and C.J. Michel, Flow-Mediated Effects on Travel Time, Routing, and Survival of Juvenile Chinook Salmon in a Spatially Complex, Tidally Forced River Delta. Canadian Journal of Fisheries and Aquatic Sciences.

Robinson, A., Safran, S., Beagle, J., Grenier, L., Grossinger, R., Spotswood, E., Dusterhoff, S., Richey, A. 2016. A Delta Renewed: A Guide to Science-Based Ecological Restoration in the Sacramento-San Joaquin Delta. Delta Landscapes Project. Prepared for the California Department of Fish and Wildlife and Ecosystem Restoration Program. A Report of SFEI-ASC’s Resilient Landscapes Program. SFEI Contribution No. 799. San Francisco Estuary Institute – Aquatic Science Center.

Weins, J., et al. 2017. “Facilitating Adaptive Management in California’s Sacramento–San Joaquin Delta.” San Francisco Estuary and Watershed Sci. 15.

Posted in California Water, Delta, Sacramento-San Joaquin Delta | Tagged , , , , , , , , , , | 6 Comments

Drought Water Right Curtailment – Analysis, Transparency, and Limits

Eel River June 2014

Drought shortage by HUC12 in the Eel River basin for June 2014. Red shaded basins have more shortage. Diversion points are shown as squares (riparian rights) and triangles (appropriative rights), scaled in size by use quantity. Web-based maps can show analysis results. (Lord 2015)

By Jay Lund, Ben Lord, Andrew Tweet, Wesley Walker, Chad Whittington, Reed Thayer, Jeff Laird, Quinn Hart, Nicholas Santos, William Fleenor, Julia Pavicic, Lauren Adams, and Bradley Arnold

Drought often means not having enough water to satisfy all water-right holders.

Assessing which water-right holders should curtail their use and by how much is not simple.  California’s complex water rights system includes two water law doctrines: seniority-based appropriative water rights (“first in time, first in right”) and older and generally higher-priority English common-law-based riparian rights (where shortages are shared proportionally across all riparian right-holders).  Assessing curtailments is further complicated by the complex hydrology of large river basins with many sub-basins and local inflows, as well as hundreds or thousands of water right holders scattered throughout these basins with different water use quantities, priorities, and return flows.

Faced with such a daunting task of many complexities and uncertainties, water right administrators have some reluctance to suggest or enforce water right curtailments, even during droughts.  This reluctance works against the property rights of senior right-holders, reduces environmental flows, and hinders user water supply investments, agreements, and markets.

Fortunately, the legal logic of water right doctrines can be represented mathematically.  In the latter years of the 2012-2016 drought, the State Water Resources Control Board funded research at UC Davis to suggest newer methods for analyzing drought water right curtailments in California.  Although these methods were not used during the drought, they point to a more formal way to analyze drought water right curtailments, and quantify likely uncertainties from such analyses which require additional technical work or policy determinations.

The methods, now published (Lord et al. 2018), combine established databases of water right-holders and water availability forecasts with mathematical representations of water law logic and distributed water balances.  All data is stored in spreadsheets for easy review, and public-domain software is used to allocate available water to water users scattered across large basins.

Initial software implementations of these methods have been made for the Eel, Russian, Sacramento, and San Joaquin watersheds.  These are summarized in the table below and detailed in the five masters’ theses under further reading.

Basin Area (square miles) Number of Sub-basins Water right-holders
Eel River 3,684 113 683
Russian River 1, 485 43 2,015
Sacramento River 26,500 769 4,282
San Joaquin River 15,600 443 2,823

These analyses have also included early explorations of how robust curtailment model results are to uncertainties in overall and local water availability estimates due to uncertain flow forecasts, inaccuracy in hydrologic models and return flows, reservoir releases, and water use estimates.

Some overall findings are:

  1. So far, the spreadsheet models seem to work well, seem understandable for stakeholders and local experts, and can be tailored to local conditions. (Every watershed has local oddities.)
  2. Substantial uncertainties exist in the underlying data for water availability and use calculations: forecasts of basin and local inflows, return flows, and right-holder water use and diversion locations. Although much data is available, estimation and measurement errors are unavoidable for such large complex systems.  There will always be need for policy judgement and interpretation.  Legal and policy controversies, and resultant uncertainties, are also likely regarding particular water right and contract issues.
  3. Local environmental flow requirements are systematically lacking across all basins examined, and were largely unavailable for inclusion in these analyses.
  4. Simple rules can often be made before the onset of drought to forewarn or assure water right holders about the likely extent of use curtailments that will be needed.
  5. Simplifications can and must often be made. All errors are not important and important errors are not uniformly distributed across basins.  Most water users are very small and errors tend to affect upper watersheds more where estimate errors are greater relative to stream flows.
  6. The methods developed can be useful inputs to water user and agency curtailment decisions, with interpretation and discussion, and are likely to improve significantly with use. Most models improve with sustained application, but usually need an initiation period of interpretation, refinement, and scrutiny.
  7. A common spreadsheet analysis framework should make it easier for local experts, interests, and state water right regulators to develop a common technical understanding of water right curtailments, and more testable and precise descriptions of their disagreements and implications. Results can be displayed easily on maps, tables, and charts.

California needs a better and common water accounting system (Escriva-Bou et al. 2016).  Hopefully available data and more public analysis will reduce the technical controversies of water right administration, particularly during drought.  The mathematical representation of legal doctrines should shorten, better structure, and focus many water right and management controversies.

The authors are or were with the UC Davis Center for Watershed Sciences.  The web site shows modeled results for the Eel River in the summer of 2014 at the individual water right level.

Further reading

Escriva-Bou, A., H. McCann, E. Blanco, B. Gray, E. Hanak, J. Lund, B. Magnuson-Skeels, and A. Tweet. Accounting for California’s Water – Technical Appendix, 177 pp., PPIC Water Policy Center, San Francisco, CA, July 2016.

Escriva-Bou, A., H. McCann, E. Hanak, J. Lund, and B. Gray. Accounting for California’s Water, 28 pp., PPIC Water Policy Center, San Francisco, CA, July 2016.

Lord, B. (2015), “Water rights curtailments for drought in California: Method and Eel River Application,” Master’s thesis, Department of Civil and Environmental Engineering, University of California – Davis.

Lord, B., B. Magnuson-Skeels, A. Tweet, C. Whittington, L. Adams, R. Thayer, and J. Lund, “Drought Water Right Curtailment Analysis for California’s Eel River,” Journal of Water Resources Planning and Management, ASCE, Vol. 144, No. 2: 04017082, February, 2018.  Pre-publication version available here.

Pavicic, J. (2017), “Uncertainty in Water Right Analyses: Overpromising versus Over-curtailing,” Master’s report, Department of Civil and Environmental Engineering, University of California – Davis.

SWRCB and others on the calculation of water availability in 2014-2015.

Tweet, A. (2016), “Water Right Curtailment Analysis for California’s Sacramento River: Effects of Return Flows,” Master’s thesis, Department of Civil and Environmental Engineering, University of California – Davis.

Walker, W. (2017), “Drought Water Right Allocation Tool Applied to the San Joaquin River Basin,” Master’s thesis, Department of Civil and Environmental Engineering, University of California – Davis.

Whittington, C. (2016), “Russian River Drought Water Right Allocation Tool (DWRAT),” Master’s thesis, Department of Civil and Environmental Engineering, University of California – Davis.

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