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 | 1 Comment

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.

Posted in California Water, Drought, Tools | 1 Comment

Advice on Voluntary Settlements for California’s Bay-Delta Water Quality Control Plan Part 1: Addressing a Manageable Suite of Ecosystem Problems

by Jeffrey Mount, PPIC Water Policy Center


The State Water Resources Control Board and the parties seeking to incorporate voluntary settlement agreements in the Bay-Delta Water Quality Control Plan should identify a specific, tractable set of problems that can be addressed over the next 15 years through this plan. We urge the participants to focus a near-term Delta plan on:

1) increasing food-web productivity in the Delta,

2) maximizing high-quality habitat that favors native plants and animals, and

3) improving water quality through nutrient management.

These efforts should recognize the inadequacies of actions focused on single species recovery, and instead focus on the simultaneous and integrated management of flows, tides, and landscapes to improve overall ecosystem function and condition.


The State Water Resources Control Board is revising its Bay-Delta Water Quality Control Plan. The plan is critical for water management because it prescribes water quality and flow requirements in the Sacramento-San Joaquin River and Delta. The Board is considering incorporating Voluntary Settlement Agreements between affected parties to guide development of its water quality plan.

Members of the Brown administration asked a small group of us to offer views on elements that should be considered in such settlements. Each of us met the following criteria: 1) are not part of the settlement negotiations, 2) do not represent any interested stakeholder, and 3) have expertise in water and ecosystem management in the Delta watershed and the San Francisco Estuary. We have prepared three blog posts that reflect our discussions and conclusions. This is the first in the series.

The Delta Challenge

Balancing the competing interests for water in the Delta and its watershed is one of California’s most vexing water policy challenges. This challenge stems from the high economic value of this water throughout the watershed and to export areas, and the highly disrupted ecological conditions of the rivers, the Delta, and the greater San Francisco Estuary. Management for “co-equal” goals, as required by the Delta Reform Act, involves difficult trade-offs that can never fully satisfy all interests.

While there can be value in seeking to simultaneously address all of the many Delta challenges, we think it is more realistic to identify a smaller, well-defined set of problems that can be addressed in the near term (15 years for purposes of this discussion). This requires identifying a set of linked priority actions that might help address ecosystem problems while providing information about how to better manage the Delta in the future. And because we are uncertain about their effectiveness, any suite of actions must include adequate funding and suitable governance for the science needed to test and refine these actions.

Here we recommend three problem areas to address over the next 15 years, as well as three management tools to use in addressing these problems. Two subsequent posts will recommend priority actions and explore possible funding and governance structures.

Toward a Manageable Set of Delta Problems

The Delta and its watershed have many problems. Some will require decades to address (e.g., adaptation to sea level rise and climate change, and improving storage and conveyance). We recommend that the settlement agreements emphasize problems that can be addressed in the near term and help build foundations for long-term solutions. We focused on three fundamental ecological problems:

  • The Delta has become a low-productivity estuary. Reclamation of the Delta landscape eliminated 98% of its high-productivity wetland habitats, leaving an estuary where growth of fish and invertebrates is limited by a small food supply. Low productivity at the base of food webs constrains our ability to meet biological goals for the Delta (Cloern et al. 2016).
  • Ecosystem conditions favor non-native plants and animals over many native species. Current conditions support novel assemblages of organisms that have no historic analog and are difficult to manage. Many non-native species prey on or compete with desirable native fishes. Invasive clams deplete food web productivity. And non-native aquatic vegetation reduces habitat quality for native species and promotes non-native predatory fish (Brown et al. 2016).
  • Water quality is declining. Degradation of water quality by nutrients, pesticides, and other contaminants is affecting human uses of Delta water for recreation and water supply and likely causing harm to native species. An example is the increasing occurrence of blooms of the toxic cyanobacteria Microcystis (Lehman et al. 2010, Brooks et al. 2012).

For several decades, Delta water management has been driven by efforts to recover several fish species listed under the federal and state Endangered Species Acts. These fishes are no longer reliable indicators of changing ecosystem condition, due to their small population sizes. We recommend that the settlement agreements and the Water Quality Control Plan take an ecosystem-based approach that explicitly recognizes that addressing these three fundamental problems will improve conditions for a wide range of terrestrial, wetland, and aquatic plants and animals—including listed fish species—as well as human uses of Delta water.

Three Tools to Address These Delta Problems

To improve productivity, habitat, and water quality, the Water Quality Control Plan will need to employ a range of tools. These include:

  • Managing freshwater flows. Regulating flows into and out of the Delta has been the primary emphasis of past water management actions, and will continue to be important. The focus has been on setting minimum flow and water quality requirements that result in outflow from the Delta into San Francisco Bay, and on regulating export flows when fishes of concern are likely to be harmed by export pumping (Gartrell et al. 2017). A range of flow attributes will need to be managed to address the three near-term ecological problems discussed above. These include: flow regime (frequency, magnitude, duration, timing), quality (including salinity, nutrients, and toxins), and the geographic application of freshwater flows. Flow management will be more effective in confined regions where existing flows are small, rather than broadly across the entire Delta (Brown et al. 2008). More ecologically-effective flow management will require flexibility to respond to new information and changing climatic and hydrologic conditions (Mount et al. 2017).
  • Managing tides. Water quality and circulation in the estuary is largely driven by tides. For most of the Delta, tidal flows dwarf freshwater inflows, particularly in dry times. Historic management of the Delta has viewed tides as a constraint, rather than an opportunity to improve ecosystem conditions. New approaches must accommodate or harness tidal energy to meet flow, habitat, and water quality objectives. This includes considering how changes in inflows and landscapes in one area may affect tidal energy elsewhere (Enright 2014).
  • Managing landscapes. Although most of the focus on Delta management has been on flows, the historic transformation of the Delta through channelization and reclamation of wetlands has arguably had a greater impact on ecosystems. To use freshwater inflows and manage tidal energy more effectively, alterations of flow must be paired with strategic changes to the landscape. These changes may include reconnecting landscapes to tidal action and flood flows and altering existing channels in ways that improve ecological conditions and water quality (Robinson et al. 2016, Durand 2017).

These three tools—managing freshwater flows, tides, and landscapes—must be applied in concert to address the three near-term problems identified here. Applying any one of these tools without the others substantially reduces the likelihood of success.

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 (SFSU), Jay Lund (UC Davis), Jeffrey Mount (PPIC), and Peter Moyle (UC Davis).

Further Reading:

Brooks, M. L. et al. 2012. Life Histories, Salinity Zones, and Sublethal Contributions of Contaminants to Pelagic Fish Declines Illustrated with a Case Study of San Francisco Estuary, California, USA. Estuaries Coasts 35: 603-621.

Brown, L. R., W. Kimmerer, and R. Brown. 2008. Managing Water to Protect Fish: A Review of California’s Environmental Water Account. Environ. Manage. 43: 357-368.

Brown, L. R., W. Kimmerer, J. L. Conrad, S. Lesmeister, and A. Mueller-Solger. 2016. Food Webs of the Delta, Suisun Bay, and Suisun Marsh: An Update on Current Understanding and Possibilities for Management. San Francisco Estuary Watershed Sci. 14.

Cloern, J. E., A. Robinson, A. Richey, L. Grenier, R. Grossinger, K. E. Boyer, J. Burau, E. A. Canuel, J. F. DeGeorge, J. Z. Drexler, C. Enright, E. R. Howe, R. Kneib, A. Mueller–Solger, R. J. Naiman, J. L. Pinckney, S. M. Safran, D. Schoellhamer, and C. Simenstad. 2016. Primary Production in the Delta: Then and Now. San Francisco Estuary and Watershed Science 14.

Durand, J. 2017. Evaluating the Aquatic Habitat Potential of Flooded Polders in the Sacramento-San Joaquin Delta. San Francisco Estuary and Watershed Sci. 15.

Enright, C. 2014. Physical processes and geomorphic features. Pages 45-64. In Moyle, P.B., A. D. Manfree, and P. L. Fiedler. 2014. Suisun Marsh: Ecological History and Possible Futures. Berkeley: University of California Press.

Gartrell, G., Mount, J., Hanak, E., Gray, B. 2017. A New Approach to Accounting For Environmental Water: Insights from the Sacramento-San Joaquin Delta. Public Policy Institute of California.

Lehman, P. W., S. J. Teh, G. L. Boyer, M. L. Nobriga, E. Bass, and C. Hogle. 2010. Initial Impacts of Microcystis aeruginosa Blooms on the Aquatic Food Web in the San Francisco Estuary. Hydrobiologia 637: 229-248.

Mount, J., Gray, B., Chappelle, C., Gartrell, G., Grantham, T., Moyle, P., Seavy, N., Szeptycki, L., Thompson, B. 2017. Managing Freshwater Ecosystems: Lessons from California’s 2012-16 Drought. Public Policy Institute of California.

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: Richmond, CA.

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

Weston, D. P., D. Chen, and M. J. Lydy. 2015. Stormwater-Related Transport of the Insecticides Bifenthrin, Fipronil, Imidacloprid, and Chlorpyrifos Into a Tidal Wetland, San Francisco Bay, California. Sci. Total Environ. 527: 18-25.

Posted in California Water, Delta | Tagged | 2 Comments

Lessons for SGMA from other State-Local Collaborations

by Dave Owen

California’s Sustainable Groundwater Management Act is known primarily for establishing statewide requirements for sustainable groundwater management.  But the statute did another important thing: it introduced an intriguing yet relatively rare model of state and local governance into groundwater management.

Typical state and local governance models involve delegating authority to local governments, with state intervention occurring on an ad-hoc basis (if at all); or, alternatively, keeping all authority at the state level.  SGMA, however, mandates local planning and implementation and state-level administrative review.

If SGMA involved the federal government and a state, there would be nothing new about this approach.  Analogous arrangements dominate federal-state relationships, where they are known as “cooperative federalism” systems (the word “cooperative” is not always descriptively accurate, but the phrase has stuck).  The Clean Air Act’s state implementation planning requirements, which served as a template for SGMA, are just one prominent example, and similar models recur in fields ranging from telecommunications to health care.

But in state-local relationships, such systems are much rarer, and state-local relationships differ from federal-state relationships in some important ways.  That rarity and those differences raise two additional questions: can SGMA’s unconventional approach to state and local governance succeed, and, if it can, what will it take to ensure that success?

It’s hard to use SGMA itself to answer these questions; the statute is too new.  So, three other long-standing governance programs with analogous structures were examined, using interviews with experienced government staff, private attorneys, and planners.  The results of that inquiry appear in this paper.

In Oregon and, until recently, Florida, land use regulation follows similar local-state models; and for decades California has subdelegated substantial air quality planning responsibilities from the Air Resources Board to local air districts. For SGMA, the study leads to several conclusions:

1. “Cooperative subfederalism” is a promising model.

When California adopted SGMA, it seemed risky to ask local governments to take the lead.  Since 1994, when the Third District Court of Appeal decided Baldwin v. County of Tehama, the authority of California’s local governments to regulate groundwater use had been clear, yet few of them had done so effectively.  Would a state mandate really make a difference?  Yet the interviewees were strikingly and consistently positive in their reviews of a cooperative subfederalism model.  They never claimed that governing within such a system was easy, and no one expects SGMA implementation to go smoothly.  But they generally agreed that a joint federal-state governance model was well-suited to the governance challenges of SGMA.

2. Making this model work requires highly interactive governance.

Some of the legal-academic literature on federalism and many United States Supreme Court cases have emphasized the importance of preserving distinct spheres for different levels of government. Yet interview subjects consistently emphasized the importance of integration, communication, and overlap.  Cooperative governance arrangements succeed, they said, when communication occurs early and often, and when the state’s approach is very hands-on.

For SGMA, this will mean a lot of meetings and conference calls.  But a secondary message that emerged, particularly from the Oregon interviews, was that the geography of interaction matters.  Oregon land use officials emphasized the importance of regional offices within the state land use agency; these offices operated as important interlocutors between Salem and local governments.  Some also emphasized the importance of sending the state’s decision-making board out on location, so that its members could see some of the areas in controversy and citizens outside the capital could see their state agency in action.  Similar benefits could arise for SGMA, and perhaps DWR and the SWRCB should budget for regional staff and road trips.

3. The state has to invest heavily in building local capacity, and in supporting local decision-making where capacity is lacking.

Another theme of traditional federalism literature is the idea that delegation enables the delegating government to conserve resources. The federal government, according to this way of thinking, delegates to states partly to accomplish things it lacks the budget and staffing to do on its own.  Similarly, California might delegate groundwater planning responsibilities to local governments as a way of getting around staffing and resource limitations at the State Water Resources Control Board and the Department of Water Resources.

To anyone thinking this way, the interviewees’ message was, “don’t get your hopes too high.”  They emphasized, instead, that the state had to invest major resources in developing and supporting local capacity, and in performing tasks that under-resourced local governments could not handle themselves.  They saw benefits in delegation, but saving the state money wasn’t one of them.

For SGMA, that suggests that sometimes the state will need to play a major role in helping GSAs develop their plans.  Developing detailed plan templates may be helpful, and sometimes DWR and the SWRCB may need to imitate their counterparts at the Air Resources Board and actually do GSAs’ modeling for them.  Fortunately, the state already is doing some of this work.  This research suggests it will need to do much more, and that while local agencies’ needs for state support will evolve, they will never really go away.

4. Specificity and clarity matter (but it isn’t always clear whether they will be helpful or harmful).

Another dilemma that often arises with delegation programs is the choice between open-ended and highly specific mandates.

Both SGMA and its implementing regulations provide examples of this dilemma.  The statute itself defines its central goal—sustainability—in somewhat vague terms (which are then defined with other somewhat vague terms), leaving implementing agencies some discretion to decide what outcomes the statute actually forbids.  And DWR’s implementing regulations require “substantial,” rather than meticulous, compliance, potentially adding more wiggle room.

Many interview subjects raised doubt about this kind of approach, and emphasized the importance of highly specific mandates in clarifying expectations and compelling action.  Others emphasized the importance of flexibility and criticized highly specific mandates for making decision-making overly legalistic.  Still others noted that striking an effective balance between specificity and flexibility was one of the most difficult challenges they had faced.  The implications for SGMA are uncertain, except for the basic point that striking this same balance is going to be hard.  But the interviews provide cause for concern that the combination of a flexible mandate and a flexible compliance standard may wind up creating unpredictability and undercutting motivations to impose controversial regulatory controls.

In summary, California’s selection of a collaborative state-local governance model was a sensible first step.  But making that model succeed is going to be hard work.

Dave Owen ( is a professor at the University of California, Hastings College of the Law.

Further reading:

Cannon-Leahy, Tina.  Desperate Times Call for Sensible Measures: The Making of the California Sustainable Groundwater Management Act.  Golden Gate Envtl. L.J. 9, no.4. 2015.

Daniels, Katherine & Sullivan, E., Oregon’s 40-Year-Old Innovation: A Remarkable Planning Program Faces a Milestone — and Continuing Challenges. Planning, Feb. 2013.

Davidson, Nestor.  Localist Administrative Law.  Yale L.J. 126, no. 3. 2017.

Gerken, Heather.  Federalism All the Way Down.  Harvard L. Rev., v. 124, no.1. 2010.

Kiparsky, Michael, et al.  Designing Effective Groundwater Sustainability Agencies: Criteria for Evaluation of Local Government Options.  University of California, Berkeley, 2016.

Owen, Dave. Cooperative Subfederalism, UC Hastings Research Paper No. 258, 59 Pages Posted: 18 Nov 2017 Last revised: 22 Jan 2018, University of California – Hastings College of the Law,

Pelham, Tom et al., Twenty Years Later: Three Perspectives on the Evolution of Florida’s 1985 Growth Management Act.  Planning & Environmental Law.  58, no.7.  2006.

Powell, David L.  Growth Management: Florida’s Past as Prologue for the Future. Florida St. L. Rev. 28, no.2.  2000.

Walker, Peter A. and Hurley, P.T.  Planning Paradise: Politics and Visioning of Land Use in Oregon.  University of Arizona Press, 2011.

Weinstein-Tull, Justin.  Abdication and Federalism.  Colum. L. Rev. 117, no.4.  2017.

Posted in California Water, Groundwater | Tagged | 1 Comment

Ecological Incentives for Delta Water Exports

by Jay Lund and Peter Moyle

All parties in the Delta have an interest in a healthy ecosystem and in healthy water exports.  Without a healthy ecosystem, endangered species requirements increasingly intrude on water exports and Delta landowners.  Without healthy water exports, the south and central Delta becomes dominated by brackish agricultural drainage and state interest in funding local levees diminishes.  The Delta, in essence, is the hostage of all interests.

The hostage is not doing well, but it is easier for stakeholders to battle over management than to find common cause.  A better framework for compromise and cooperation is needed.

The many parties to Delta policy will never enthusiastically agree on Delta exports and outflows or how to adapt outflow and export quantities to future conditions.  Scientific complexity and uncertainty make it impossible to specify exactly what the ecosystem needs to be healthy.

Currently, minimum flow requirements are employed to support in-Delta water quality for exports and in-Delta users, and to support some threatened native fish species.  These standards have not been sufficient (or effective) to support native species and have exacerbated water quality problems for some areas and purposes.  Moreover, the fixed standards are not readily adaptable to changing conditions or experimentation.  Arguments over Delta standards have fostered much conflict, but little forward-looking insight or compromise.

Give the ecosystem shares of Delta water export capacity

We propose that water export capacity and flow authority be allocated to various export and ecosystem authorities, and then managed flexibly.  This would create incentives for all parties to cooperate in Central Valley Project (CVP) and State Water Project (SWP) operations and to invest in ecosystems and Delta levees, especially where landowner levee interests coincide with ecosystem and export objectives.  Management for ecosystem purposes would shift at least partially from legal regulation to operational governance and active stewardship. This approach would work under the existing configuration of the Delta and could be adapted if one or two tunnels are constructed to convey water from the lower Sacramento River to the south Delta pumps.

The ecosystem share of export capacity could remain unused at times when ecosystem objectives are most sensitive to water exports or be rented to raise funds for ecosystem improvements.  Fish require both flows and habitat, and resources are needed to acquire and assure both at the proper times and locations.  Ecosystem managers would become more directly aware of the trade-offs of exports and revenues for ecosystem support and the value of experimentation and flexibility.

This framework also provides incentives for water exporters to invest in both desirable water infrastructure and the future of reconciled ecosystems with desirable characteristics.  To the extent that native fishes prosper, more export capacity becomes reliably available.  The flexible allocation of export capacity across export and ecosystem purposes also establishes a framework for cooperation and pragmatic negotiation and sharing of risks.

Define flexible water export shares for the ecosystem and exporters

We propose six “pools” of Delta water with different authorities for water export.  These pools could vary with hydrologic conditions and are shown below for three different types of water years:

(1) Required Delta outflows. This water serves overlapping needs for water quality for export and in-Delta uses and endangered species (Gartrell et al 2017a, b).  It would be defined as a conventional minimum flow requirement.

(2) Water diverted upstream of the Delta. This pool consists of the water diverted for upstream agricultural, municipal, business, and wetlands uses upstream of the Delta. It accounts for most human water use in the system.  This pool might be limited based on hydrologic and ecosystem conditions.

(3) Reliable Delta Exports. This pool would be available for export uses under the exclusive control of the CVP and SWP.

(4) Performance-Based Exports. This pool would allow additional water export capacity if specified ecosystem function and fish condition targets are achieved.  If these targets are not met, this water would augment Delta outflows.

(5) Ecosystem-Discretion (Adaptive Management) Water. This pool would be additional export capacity available at the discretion of an ecosystem steward for lease to export or in-Delta users, augment Delta outflows, or support adaptive management experiments.

(6) Uncapturable flows. Wet years (such as 2011 or 2017) have significant uncapturable water in excess of these five categories (so-called “spill”).  Even dry years have some uncapturable inflows discharging to San Francisco Bay when export and storage capacities are insufficient (Gartrell et al. 2017a, b).

Proposed allocation framework for Delta export capacity (not at all to scale). The three Delta exports pools would be controlled by different interests.

The interested parties would negotiate the details of these pools, but ultimately both the export quantities and the other conditions would govern the use of existing or new water export facilities, subject to approval by the State Water Resources Control Board (SWRCB) in consultation with state and federal fisheries agencies.

Additional thoughts on the three export pools, including risk-sharing, incentive structures, and operational considerations

Reliable Delta Export Pool.  This limited Delta export capacity would be assured, but vary with hydrologic conditions.  It establishes a secure supply for exporters making major long-term investments, and would be available as long as required Delta outflows are met.

Performance-Based Export Pool.  This water export quantity would be determined annually by achievement of specific ecosystem function, fish condition, or fish population objectives.  This pool is essentially a flexible minimum Delta outflow requirement, with its availability for exports contingent on improving ecosystem conditions. Initially, perhaps 90 percent of the pool would be allocated based on achieving ecosystem function objectives (flow patterns, habitat functions, etc.).  Over time, this share should recede, with growing weight for meeting fish condition or population objectives.  The higher initial emphasis on ecosystem function objectives would provide incentives for exporters to invest in improving flow management, large-scale habitat restoration projects, and reducing the effects of other stressors, such as pesticides, particularly in the early years of the agreement when uncertainty is great and before fish populations could be expected to respond.  The performance measures could be negotiated as part of an agreement and periodically updated, perhaps with initial suggestions from an independent scientific group.  The SWRCB (perhaps in consultation with the Delta Watermaster) would determine if performance conditions have been met.

Ecosystem Discretion (Adaptive Management) Pool.  Export capacity from this pool would be allocated by an Ecosystem Steward – perhaps a special office in the California Department of Fish and Wildlife, in consultation with the U.S. Fish and Wildlife Service, the National Marine Fisheries Service, and an external independent science panel.  This capacity could be used to increase outflows or be leased at negotiated rates to willing export users and/or upstream water sellers.  Revenues from the leases would help support ecosystem management and improvements for the Delta ecosystem.

(Another way to administer this pool would be to provide guaranteed funding to the Environmental Steward to purchase export capacity and thereby increase net Delta outflows. Such funds would need to be built into the agreement, not subject to the unreliability of legislative appropriations or voter-approved water bonds.)

The Ecosystem Steward would face an annual decision on how best to protect the Delta ecosystem through a mix of Delta outflow and funding for other environmental projects.  This pool also would provide flexibility for adaptive management and would likely require some federal approval or acceptance.

Sharing Risks.  The future is an uncertain place.  Any agreement implies an allocation of both benefits and risks.  Naturally, all sides prefer to shift risks to others.  Scientific uncertainties regarding Delta fish population performance make it more difficult for wildlife agencies to commit to a long-term permit that omits population performance contingencies; otherwise, they bear the full risk of continued species decline. In the framework proposed here, the Performance-based and Ecosystem Discretion export pools allow some flexible risk-sharing and experimentation over time, while the required Delta outflow and reliable export amounts somewhat limit both environmental and economic risks.

Incentives.  Risk-sharing must be accompanied by positive incentives for all parties to make the system work for the ecosystem and the economy.  This proposal would give water exporters incentives to improve both ecosystem functions and fish populations, while also providing water export reliability needed to justify large capital investments that improve export water quality and ecosystem functions.  The framework also would give ecosystem managers incentives to enhance water export reliability as a way to help improve ecosystem conditions and fish populations.

Diversion location.  The Ecosystem Steward’s authority might include how to divide exports between the existing south Delta pumps and any new upstream intakes to maximize ecosystem benefits for any amount of Delta exports. For instance, upstream diversions through a tunnel might be favored during the spring, because spring export diversions from the south Delta pumps disrupt migration of estuarine fishes.

Annual and seasonal variability.  Hydrologic variability could be incorporated by varying the volume of each of the three pools based on a water year index, as illustrated in Figure 1.  A seasonal distribution of export capacity might be imposed generally or at particular intake locations to reflect seasonal fish migrations and other desired ecosystem functions, perhaps with substantive discretion for the Ecosystem Steward.

Special cases.  A re-opener clause would be desirable if the future changes radically (perhaps from an earthquake, levee failures, or new legal or regulatory conditions).  Extreme droughts also might trigger a re-opener clause.  Such aspects are discussed for Ecosystem Water Budgets by Mount et al. (2017).  Development of infrastructure or operations to capture currently uncapturable flows might trigger additional negotiation.

Evolving understanding.  Evaluation standards for the Performance-Based Pool should evolve over time based on improved scientific understanding of desirable ecosystem functions and the effects of water diversions, changes in flow and temperature, pollutant discharges, and other stressors on fish populations and water quality needs.  Such revisions might occur at regular intervals or in response to scientific advances. An independent science panel would initiate and oversee the revision process.  By providing flexibility to support adaptive management, Ecosystem Discretion exports would also provide information improving ecosystem, water quality, and water supply management.

Consistency with Endangered Species Acts and Other Environmental Laws

Mount et al. (2017) discuss the legal authorities and requirements for such more flexible ecosystem management.  Such proposals, though novel, can, in theory, be consistent with federal and state Endangered Species Acts.  Although the federal and state ESAs allow for the taking of a few individuals of protected species as an unavoidable consequence of project operations, they also require that such incidental takings be accompanied by measures to restore the species to sustainable populations and protect the species’ habitat.

Our framework acknowledges need for more than a fixed minimum ecological flow.  Environmental managers also need flexibility to adaptively manage flows and system improvements that reduce many stresses (e.g., better physical habitat, reduced pollution, and better hatchery management). The Ecosystem Decision Pool allows an Ecosystem Steward to adaptively adjust flows.  The Performance-Based Export Pool allows some additional exports if improvements in habitat, water quality, project operations, or other factors demonstrably benefit protected species or their habitats.

Sharing Risks and Incentives

In the declining Delta ecosystem, passive regulatory approaches have not been effective.  The approach presented here adds resources, flexibility, and incentives for continuous attention, which can accommodate adaptive management with changing and uncertain conditions.  It also can better integrate water operations with other habitat improvements in the Delta ecosystem.

We offer this framework and proposed allocation of Delta water export capacity in the spirit of creative problem-solving. Many variants of this idea might provide a workable approach for the WaterFix, environmental flow, and more general Delta negotiations.  The approach has similarities with Delta export management and Ecosystem Water Budget (EWB) strategies previously proposed (Lund et al. 2010; Mount et al. 2017).

This proposed framework suggests a middle path for managing Delta exports with shared risks and incentives: An environmental protective baseline is supplemented by performance-based restrictions on water exports.  Water exporters receive a baseline of reliable water export capacity and additional export capacity for approved ecosystem improvements and actual improvements in fish populations or conditions. (The baseline for future performance of fish populations might account for declining populations anticipated from climate change and other external factors, with credit for improving performance above a declining baseline.) And environmental managers receive defined capacity that they may use flexibly, either to directly augment environmental baseline flows, support adaptive management experiments, or raise funds for additional ecosystem enhancements.

Such a middle way would help to move all parties toward practical deals to meet the co-equal goals of improving ecosystem sustainability and water supply reliability in the Delta, within a framework that can adapt over time.  It also may help avoid mutually destructive battles and delays.

Jay Lund is a Professor of Civil and Environmental Engineering and Director of the Center for Watershed Sciences at UC Davis. Peter B. Moyle is a UC Davis Professor Emeritus of fish biology and an associate director of the Center for Watershed Sciences.

Further Reading

Delta Independent Science Board, Flows and Fishes in the Sacramento-San Joaquin Delta: Research Needs in Support of Adaptive Management, Delta Stewardship Council, Sacramento, CA, 37 pp., September 2015.

Greg Gartrell, Jeffrey Mount, Ellen Hanak, Brian Gray (2017a), A New Approach to Accounting for Environmental Water Insights from the Sacramento–San Joaquin Delta, PPIC, San Francisco, CA.

Greg Gartrell, Jeffrey Mount, Ellen Hanak, Alvar Escriva-Bou, Brian Gray (2017b), Appendix B: Water Assigned to Meeting Environmental Standards in the Delta from 1980–2016, PPIC, San Francisco, CA.

Greg Gartrell and Brian Gray (2017), Appendix A: A Brief Review of Regulatory Assignment of Water in the Sacramento–San Joaquin Delta, PPIC, San Francisco, CA.

Lund, J., E. Hanak, W. Fleenor, W. Bennett, R. Howitt, J. Mount, and P. Moyle, Comparing Futures for the Sacramento-San Joaquin Delta, University of California Press, Berkeley, CA, February 2010.

Mount, J., B. Gray, C. Chappelle, G. Gartrell, T. Grantham, P. Moyle, N. Seavy, L. Szeptycki, and B. Thompson (2017), Managing California’s Freshwater Ecosystems – Lessons from the 2012-16 Drought, Public Policy Institute of California, San Francisco, CA, November, 50 pp.

Wiens, J. , J. Zedler, V. Resh, T. Collier, S. Brandt, R. Norgaard, J. Lund, B. Atwater, E. Canuel, and H.J. Fernando, “Facilitating Adaptive Management in the Sacramento-San Joaquin Delta,” San Francisco Estuary and Watershed Science, Vol. 15, No. 2, July 2017.

Posted in California Water, Delta, Sacramento-San Joaquin Delta | Tagged , | 7 Comments

Los Angeles and the Future of Urban Water in California

by Erik Porse

Cars drive on Woodman Avenue in Panorama City, Calif., Jan. 7, 2016, beside a curb cut where rainwater runoff is directed to a bioswale in a median.  Michael Owen Baker, AP

Los Angeles is a grand American urban experiment. It brings emerging ideas into the mainstream, sometimes for better, and sometimes for worse. In the early 20th Century, it seemed fanciful to build a metropolis in a region receiving limited seasonal rainfall. But LA adopted the ideas of the time at grand scales. It built pipelines over hundreds of miles of rugged terrain to import water from the Owens Valley (1913), Colorado River (1939), and Northern California (1972). In a quest for growth, LA has always adopted new ideas to keep ahead.

A pipe feeds recycled wastewater to a holding pond to recharge an underground aquifer at the Orange County Water District recharge facility in Anaheim, Calif. (Chris Carlson, AP)

The myth of LA as a desert city persists, but belies local conditions. Los Angeles has always used local water supplies, often preferentially. The region has significant groundwater resources, and in the surrounding mountains, up to 40 inches of rain can fall annually, waiting to be captured. As early as the 1930s, LA communities began managing groundwater, limiting pumping and building large spreading basins to recharge runoff from storms. Today, LA captures and recharges 200,000 ac-ft annually on average, much more in wet years. Regional agencies also have built “purple pipe” infrastructure for water recycling, which helps recharge groundwater and irrigate landscapes. An additional 40,000-60,000 ac-ft of recycled water is recharged in local basins each year.

If LA is an urban laboratory for contemporary ideas, what can it tell us about the future of urban water management in California? Contrary to lore of a thirsty desert city, LA demonstrates some well-tested lessons for California’s continually growing cities:

  • Stormwater is already a resource in California. LA County has operated a network of spreading basins for decades with the explicit purpose of groundwater recharge. In past decades, cheap imported water supplemented local stormwater runoff and infiltration. In recent years, regional agencies have improved systems to capture more runoff and recharge recycled water. The largest annual volume of managed recharge in LA County was 630,000 ac-ft (2005-06). Managed stormwater capture in LA was largely developed and funded as part of developing groundwater adjudications. Throughout Southern California, too, the 2010 MWD Integrated Water Resources Plan (Appendix 12) reported an additional 400,000 ac-ft of active recharge in other southern counties. The challenge for future stormwater management is to combine centralized and distributed infrastructure to promote recharge and meet water quality regulations without increasing groundwater pollution.
  • Technology is important, but dull government processes are critical. New water reuse technologies offer cheaper and more efficient options for water supply and wastewater management. These will be important. But in the end, agency interactions are critical to regional success. Metropolitan areas often have complex and “polycentric” governance, with duties dispersed across many agencies. In mid-20th century LA, the myriad of public and private parties involved in LA groundwater basins had to work out collaborative governance structures. They created new entities that served as models for locally driven governance. Today, the agencies in LA responsible for capturing stormwater to recharge groundwater basins are not the agencies that pump the groundwater for water supply. Costs and benefits of projects are mismatched. Multi-benefit projects are often impeded by the difficulties of assembling collaborations with complicated accounting. Some regional progress is underway. For instance, the City of Los Angeles, through its OneWater initiative, is moving towards better integration across water agencies.
  • The “sticker price” of water is misleading. Future projects must examine the long-term costs of alternative water sources when evaluating investments. In urban areas of California, the increasing costs of imported water will likely promote more use of local sources, including stormwater and water reuse. Today, imported water looks and is cost-effective. But its costs in Southern California have steadily increased, making local alternatives equally attractive over the long-term. With or without statewide infrastructure improvements, the increased costs of imported water to Southern California cities, along with desires for regional self-reliance, are driving local agencies to invest in local sources.
  • No single agency has the answer. Regional strategies for local water supply enhancement in LA necessarily involve many agencies. The regional water importer, MWD, is examining investments in large-scale recycled water from water treatment plants. Local agencies such as the LA Department of Water and Power (LA City) and the Water Replenishment District of Southern California (WRD) are investing in ways to promote additional stormwater capture and better estimate natural recharge. The LA County Department of Public Works led a detailed analysis of opportunities to re-operate regional flood control infrastructure and retrofit urban landscapes, with the goal of maximizing stormwater capture and infiltration. Ultimately, the agencies will have to configure collaborative projects that align funding streams with desired regional outcomes.

As a city at the edge, or a canary in the coalmine, Los Angeles provides rich case studies for understanding the future of urban water management in the West.

Erik Porse is a Research Engineer in the Office of Water Programs at
CSU-Sacramento and a Visiting Assistant Researcher at UCLA.

Further reading

Blomquist, William. 1992. Dividing the waters : governing groundwater in Southern California. ICS Press, San Francisco, Calif.; Lanham, Md.

Davis, Margaret Leslie. 1993. Rivers in the desert: William Mulholland and the inventing of Los Angeles, 1st ed. HarperCollins Publishers, New York, NY.

Erie, Steven, HD Brackman. 2006. Beyond Chinatown: the Metropolitan Water District, growth, and the environment in southern California. Stanford University Press, Stanford, CA.

Hevesi, J.A., and Johnson, T.D., 2016, Estimating spatially and temporally varying recharge and runoff from precipitation and urban irrigation in the Los Angeles Basin, California. USGS Scientific Investigations Report 2016–5068, 192 p.,

Los Angeles City Department of Water and Power (2015). Urban Water Management Plan. Los Angeles, CA

Los Angeles County Department of Public Works and US Bureau of Reclamation. 2016. Los Angeles Basin Study: The Future of Stormwater Conservation. Final Report. Los Angeles, CA.

MWD. Integrated Water Resources Plan: 2010 Update. Technical Appendices (Appendix 12). Los Angeles, CA.

Mika, Kathryn B., E. Gallo, E. Porse, T. Hogue, S. Pincetl, and M. Gold. 2017. LA Sustainable Water Project: Los Angeles City-Wide Overview. UCLA, Los Angeles, CA

Ostrom, Elinor. 1965. Public Entrepreneurship: A Case Study in Ground Water Basin Management. Ph.D. Dissertation, University of California, Los Angeles

Ostrom, Vincent, CM Tiebout, and R Warren. “The organization of government in metropolitan areas: a theoretical inquiry.” American political science review 55.4 (1961): 831-842.

Ostrom, Vincent. 1962. “The political economy of water development.” The American Economic Review 52.2: 450-458.

Porse, Erik, KB Mika, E Litvak, KF Manago, K Naik, M Glickfeld, TS Hogue, M Gold, DE Pataki, and S Pincetl. 2017. “Systems Analysis and Optimization of Local Water Supplies in Los Angeles.” Journal of Water Resources Planning and Management. 143, no. 9 (2017): 04017049.

The LA Water Hub. UCLA California Center for Sustainable Communities. 2017.

Posted in California Water, Planning and Management, Uncategorized, Water Supply and Wastewater | Tagged , , | 7 Comments

Will Delta Smelt Have a Happy New Year?

by James Hobbs and Peter Moyle

Staff with the California Department of Fish and Wildlife trawl for Delta smelt in the Sacramento-San Joaquin Delta in 2015. (Image credit: Amy Quinton, Capitol Public Radio)

The results of 2017 surveys of Delta fishes are coming in. Already, the results are clear:  it was an unhappy year for Delta smelt.

The wet year with high outflows should have created an increase in the population, as happened in 2011.  Instead numbers stayed extremely low.  The US Fish and Wildlife Service (USFWS) estimated abundance of adults from January to February 2017 at approximately 48,000 fish. (The USFWS completed a revised adult delta smelt abundance estimation based on the CDFW’s SKT data for January and February; the point estimate was 47,786 but with confidence intervals from 22,000 to 92,000.) While this might seem like a lot of fish, for a pelagic forage species this is really low.

Abundance of Delta Smelt as reflected in the Fall Midwater Trawl index and Summer Townet index. Redrawn from data reported by the Region 3 Bay-Delta Fish and Wildlife Office.

Meanwhile the California Department of Fish and Wildlife (CDFW) Spring Kodiak Trawl Survey (SKT) index was only 3.8; this survey is aimed at adult Delta Smelt between January and May.  The CDFW SKT index has ranged from 1.8 (2016) to 130.2 (2012); the 2017 index was based on a total catch on only 39 fish. Fish surveys conducted in tidal marsh by UC Davis did not capture a single Delta Smelt in Suisun Marsh and only 1 adult in the Petaluma River-marsh in April.

Two measures of the year’s reproductive success of Delta Smelt are also taken by USFWS and CDFW. CDFW produces an index of abundance for juveniles (Summer Townet Survey-STN) and sub-adults (Fall Midwater Trawl Survey-FMWT). The STN Index ’increased’ in 2017 to 0.2, although the previous two years the index was zero. An index of zero does not mean the smelt abundance was zero, rather fish were just not captured at the index stations. We know there were still fish around because the next survey up, FMWT, caught a few delta smelt, so they were just really low in abundance. The FMWT index was lowest on record, 2, representing a total catch of only 2 individuals in October among the index stations.

The US Fish and Wildlife Service (USFWS) recently began a new monitoring program called the Enhanced Delta Smelt Monitoring Program (EDSM) which employs slightly different sampling methods to produce estimates of total Delta Smelt abundance.  Abundance estimates from USFWS varied wildly from week to week in 2017, but appeared to collapse in July and remain low through the remainder of the season.

Delta Smelt abundance estimates from the EDSM surveys, July –September 2017. Different sampling areas are represented by different colors. Vertical lines are confidence intervals around each estimate. Figures from USFWS-EDSM Sept 22 2017.

What happened in July? We can only speculate:  July is usually a month of very warm temperatures in the Delta.  Catches of Delta Smelt in the Cache Slough region and Sacramento Deepwater Ship Channel coincided with very warm water 22-23 °C  (72-73 °F).  Smelt would have been extremely stressed by these warm waters and would have likely moved downstream to the western region of the Delta where water temperatures were 2-3 °C cooler.  This may explain the increased abundance in survey 3 (Figure 2) in Suisun Bay and Marsh.  What happened after that is anyone’s guess. We certainly didn’t see these fish in our Suisun Marsh surveys.

Abundance of delta smelt remained low in all surveys after September, which interestingly, coincided with a USFWS decision to relax ESA requirements in order to maintain freshwater outflow for the fish starting in October.  Since October 1, the special EDSM program encountered only 17 Delta Smelt in a total of 366 tows.  December abundance estimates were down to less than 4,000 fish. While the abundance is extremely low, targeted efforts by UCD researchers at the Fish Conservation and Culture Laboratory were able to collect 100 delta smelt for the captive breeding program in one day, from a known area of concentration. So Delta Smelt are not yet extinct, but numbers have never been this low.

At this point it is worth reviewing some basic facts about delta smelt biology.  First, they basically have a one-year life cycle in the wild, although a few fish live a second year. Delta Smelt move upstream in the fall and aggregate in the North Delta, where presumably most spawning takes place, although beaches along the Sacramento River near Rio Vista likely are attractive to spawners (Figure 3). Fish spawn between February and June.  Most fish die after spawning, although individual smelt can spawn multiple times over several months (Le Cava et al. 2015).

Catches of delta smelt by the Spring Kodiak Trawl in January 2017, when the fish should be aggregating for spawning. This survey concentrates on delta smelt.

Most smelt spend the first few months of their short lives in western Delta (Sacramento River) or as resident fish in a few areas in the north Delta. Smelt are largely absent today from the South Delta, except when carried there by cross-Delta water movement generated by the SWP and DWR pumping plants.  Delta Smelt feed on zooplankton and spend their lives in the larger channels and bays of the upper SFE, near the surface. The life history described above actually has more flexibility than we describe; for a more nuanced view see Moyle et al. (2016) and Hobbs et al. (2017).

Some fishes with similar habitat requirements for juveniles (young of year) but with more complex life histories than Delta Smelt showed a positive response to the wet conditions.  For the FMWT, both juvenile Striped Bass and American Shad in 2017 showed some of their highest indices in recent years.  They also were abundant in Suisun Marsh and in other sampling programs.  Longfin Smelt, a distant cousin to the Delta Smelt, also showed a small uptick in abundance, while two other species monitored by FMWT, Sacramento Splittail and Threadfin Shad, showed continued low numbers. However, we note that the FMWT is a poor tool for sampling splittail and Threadfin Shad and these species are abundant in Suisun Marsh, with no strong trends (Moyle, unpublished data).

The question then becomes, why didn’t Delta Smelt respond to improved conditions as did other fishes?   One possible explanation is that there was so much water last winter that smelt were more dispersed than usual and had a hard time finding mates. This dispersion is reflected in the distribution of reproductive fish in January 2017 from the Spring Kodiak Trawl Survey. Reproductive smelt were scattered from the Sacramento Deepwater Ship Channel in the North Delta to the Napa River, with the majority of catches being single individuals. As further evidence for the distribution problem, we caught one adult in the Petaluma River in April, where they have never been encountered before. 

The abrupt decline in abundance detected by the EDSM survey in late July (Figure 2) may be an indicator that Delta Smelt recruitment (survival from larvae to adulthood) is impacted by summer temperatures. Research on temperature tolerance suggests Delta Smelt are very sensitive to warm waters (Komoroske et al. 2014; 2015, Jeffries et al. 2016). Since the beginning of drought in 2012 water temperatures have been creeping up, warming earlier and cooling off later in the year. Is this a signature of climate change? It may be too early to say, but if this year stays dry with low outflows in late summer, smelt that survive will have to have find cool-water refuges somewhere, perhaps the lower Sacramento River.

When numbers are so low, as they clearly are for smelt, random factors in sampling, in distribution of spawners, in spawning success, and other factors can make a big difference to the total population or to the indices.  If smelt are concentrated in just a few places for spawning, then physical changes in the spawning habitat or coincidence of spawning with concentrations of egg and larval predators (e.g., Mississippi Silverside) can be lethal.   Competition from the introduced, similar Wakasagi Smelt could be problem, which seems to be increasing in numbers.  Wakasagi also hybridize with Delta Smelt, but the offspring are apparently sterile, so this could interfere with spawning in the wild.  In other words, when Delta Smelt numbers are low, many things can keep them from rebounding, pushing them closer to extinction.

So the coming year does not look like a happy one for Delta Smelt. So far, California appears to be back in a drought pattern. Furthermore, protections from freshwater exports appears to be in question. In late December the U.S. Bureau of Reclamation announced their intentions to maximize water deliveries, as well as review and consider modifications to the 2008 RPAs for protecting smelt. One of these RPAs, the Fall X2 Action (RPA Component 3), calls for maintenance of higher than normal flows in the fall to maintain low-salinity habitat in Suisun Bay following years of above normal or high flows. In October, these regulations were relaxed by USFWS under petition from the US Bureau of Reclamation3. This will likely be something the Bureau will pursue further in their request for modifications. In addition, the Interior Department announced they will be working on changes to the Endangered Species Act under the guise of the Trump administrations Unified Agenda of Regulatory and Deregulatory Actions. Its unclear what changes to protective measures for Delta Smelt will occur in 2018, but it appears the changes will not favor the fish.

If our wishes were fishes, Delta Smelt might survive.

James Hobbs is a research scientist with the UC Davis Department of Wildlife, Fish and Conservation Biology. Peter B. Moyle is a UC Davis Professor Emeritus of fish biology and an associate director of the Center for Watershed Sciences.

Further reading:

Hobbs, J.A, P.B. Moyle, N. Fangue and R. E. Connon. 2017. Is extinction inevitable for Delta Smelt and Longfin Smelt? An opinion and recommendations for recovery.  San Francisco Estuary and Watershed Science 15 (2):  San Francisco Estuary and Watershed Science 15(2). jmie_sfews_35759. Retrieved from:

Jeffries, K.M., R.E. Connon, B.E. Davis, L.M. Komoroske, M.Britton, T.Sommer, A,E. Todgham, and N.A. Fangue. “Effects of high temperatures on threatened estuarine fishes during periods of extreme drought.” Journal of Experimental Biology 219, no. 11 (2016): 1705-1716.

Komoroske, L. M., R. E. Connon, J. Lindberg, B. S. Cheng, G. Castillo, M. Hasenbein, and N. A. Fangue. “Ontogeny influences sensitivity to climate change stressors in an endangered fish.” Conservation physiology 2, no. 1 (2014).

Komoroske, L.M., R.E. Connon, K.M. Jeffries, and N.A. Fangue. “Linking transcriptional responses to organismal tolerance reveals mechanisms of thermal sensitivity in a mesothermal endangered fish.” Molecular ecology 24, no. 19 (2015): 4960-4981.

LaCava, M., K. Fisch, M. Nagel, J. C. Lindberg, B. May, and A. J. Finger. 2015. Spawning behavior of cultured delta smelt in a conservation hatchery. North American Journal of Aquaculture 77: 255-266.

Moyle, P. B., L. R. Brown, J.R. Durand, and J.A. Hobbs. 2016. Delta Smelt: life history and decline of a once-abundant species in the San Francisco Estuary. San Francisco Estuary and Watershed Science14(2)

Moyle, P.B., J. A. Hobbs, and J. R. Durand.  2018.  Delta smelt and the politics of water in California.  Fisheries. In press (February).

Posted in Delta, Delta Smelt, Fish, Sacramento-San Joaquin Delta | Tagged , | 3 Comments

New paths to survival for endangered winter run Chinook salmon

by Anna Sturrock and Corey Phillis

The chemical composition of adult Chinook salmon otoliths (“earstones”, left image) were used to reconstruct their movements through freshwater as juveniles. Otoliths grow in the inner ear of all bony fishes and reveal daily growth increments just like tree rings when you section them (right). The researchers used a laser coupled with a mass spectrometer to measure strontium isotope ratios across these layers in order to retrace the fishes’ migration history. Image courtesy of George Whitman/UC Davis.

Many Californians have seen headlines about endangered Sacramento River Winter Run Chinook salmon (“winter run”) on the “brink of extinction.” But not many people know exactly what winter run are, nor why they are endangered.

Like all salmon, winter run reproduce (spawn) in freshwater. Their offspring migrate to the ocean as juveniles, where they feed and mature before returning to their natal stream to renew the cycle.

However, the timings of these movements differ dramatically among salmon species and populations. Winter run exhibit a suite of behaviors so unique that they are treated as a separate “species” by the Endangered Species Act (ESA) and were the first Pacific salmon to be state and federally listed as endangered in 1989 and 1994, respectively.

To help protect this endangered fish during freshwater residence, most of the Sacramento River has been designated as “critical winter run habitat” by the ESA. While winter run juveniles have occasionally been observed in intermittent streams and tributaries to the Sacramento River, no one knew how frequently they showed up, how long they stayed, nor whether these “errant teens” survived to tell the tale.

In a new study published this week in Biological Conservation, researchers from the Metropolitan Water District of Southern California, UC Davis Center for Watershed Sciences, NOAA Fisheries, and Lawrence Livermore National Laboratory used salmon otolith (“earstone”) chemistry to reveal the migration patterns and secret hang out spots used by juvenile winter run on their way to the ocean.

The surprising finding was that, in their youth, around half the successful winter run adults had wandered beyond their natal reach of the Sacramento River to feed and grow before continuing their journey to the ocean. These alternative “non-natal” habitats included Deer, Mill, Battle Creeks, the Delta, Feather and American Rivers, most of which is not designated as critical habitat under the ESA.

Juvenile Chinook salmon hide in willow branches in the American River in the California Central Valley. The American River was found to be a favorite stop off for endangered winter run youths during their perilous journey to the ocean. Image courtesy of John Hannon/USBR

Let’s take a quick step back. What are winter run and why are they endangered?

Winter run exhibit a unique combination of behaviors that sets them apart spatially and temporally from all other types of salmon. For a start, they return to freshwater in winter – hence the name.

The last remaining population began declining dramatically in the 1970s to fewer than 200 spawners by 1991, and for the last decade the census has typically been below 3000. Before we built huge, impassable dams in their path, winter run spawned in cool, high-elevation, spring-fed tributaries above the Sacramento River, such as the McCloud and Pit rivers. Today, the remaining adults spawn in a small stretch of the upper Sacramento River immediately below Keswick Dam in early summer.

You might associate salmon with grizzly bears and icy Alaskan waterfalls, not summers in Chico. The California Central Valley contains the southernmost populations of native Chinook salmon in the world. Most life stages avoid the summer heat by moving into high elevation streams or escaping to the ocean.

Winter run eggs somehow need to survive and thrive through scorching summers, when air temperatures average around 100°F. Winter run literally put all their eggs into one basket – a small, very hot basket near Redding. One day, winter run may be reintroduced into the high-elevation streams above Shasta; but for now, their future is heavily reliant on cold water reserves in the reservoir that can be released through the summer.

But egg survival is only part of the story. If the warm water temperatures don’t poach the eggs, the tiny hatchlings (termed “fry”) face a perilous ~300 mile journey to the ocean. Their migration takes them down the Sacramento River, through the Delta, the estuary and bays, and finally past Golden Gate Bridge. Along the way they need to find food and territories, fight off competitors, and avoid the hungry jaws of predators.

Again, humans have upped the ante considerably. We have lined the rivers with “riprap” (large boulders or concrete blocks) to avoid erosion, facilitate flood control, and help with water delivery; but in doing so, have turned them into super highways of fast flowing water with few places for juvenile salmon to hide or rest. We have also introduced voracious predators like striped and largemouth bass, who love to dine on our winter run friends. But the results of our study showed that winter run juveniles are more resourceful than previously realized, and often wander out of the mainstem Sacramento River into smaller tributaries to feed and grow.

How did we discover their secret stop-offs?

We used otolith (“earstone”) chemistry to re-trace the migration patterns of hundreds of winter run and identify the rivers they had visited when they were making their treacherous journey to the ocean as juveniles. We extracted the otoliths from adult carcasses on the spawning grounds, representing the precious few that survived to adulthood. Otoliths are crystalline structures that grow like a pearl in the inner ear of the fish, depositing a new layer each day and forming growth rings just like a tree. The growth rings record the ambient water chemistry, providing a permanent record of the fish’s age and lifetime movements, rather like an airplane flight recorder.

We took advantage of California’s diverse geology to find a tracer for their migration to the ocean. Natural differences in strontium isotopes released from weathering rocks allowed us to develop a chemical map of river strontium-87 signatures called an “isoscape.” We used laser ablation mass spectrometry to measure the abundance of strontium-87 in tiny (~2 weekly) intervals across the otolith growth rings – from its center (the fish’s birth) to when it entered the ocean (typically 5-10 months old). Changes in the otolith strontium-87 values acted like chemical signposts, allowing us to track their movements and favorite hangout spots.

What are the implications?

An interesting finding was that the “wandering” winter run tended to leave the mainstem Sacramento River as small fry, yet left freshwater at a similar size to the rest of the population. These results suggest that these alternative habitats provide important growth opportunities and/or predator refuge.

Map of the California Central Valley winter run spawning grounds and migratory corridor, from Keswick Dam on the Sacramento River to Chipps Island, where they exit the freshwater Delta. Red shaded areas identify the regions identified isotopically as potential non-natal rearing habitats. Inset barplot shows the proportion of winter run in different “rearing groups” by escapement year, and averaged across years. Image from Phillis et al. (2018)

By using multiple habitats over their lifecycle, winter run are proving to be canny strategists. If you liken each habitat to a financial stock, winter run are effectively spreading risk by investing in a more diverse portfolio. By spreading themselves across the rich tapestry of freshwater habitats, winter run are reducing competition in natal habitats while potentially finding even better spots along the way.

Not only this, but differing growth opportunities can result in increased variability in rearing duration and ocean entry timing. Upwelling and prey dynamics are notoriously variable off the Californian coast; if a cohort all enters the ocean at the same time and miss the favorable window, they can all perish. Such “match-mismatch” dynamics are thought to be the leading cause of the precipitous stock collapse that occurred in 2007. By broadening this window, winter run are adding another layer of resiliency.

In summary, juvenile winter run have shown themselves to be masterful risk spreaders, taking their future into their own fins and using rearing habitats across a far broader geographic region than previously known. The findings open up exciting restoration and conservation opportunities for aiding species recovery, and bring new hope for the future of this endangered fish.

Anna Sturrock (@otolithgirl) is an Assistant Project Scientist at the Center for Watershed Sciences using otoliths to reconstruct juvenile salmon growth and habitat use. Her broader interests lie in linking fish ecology, science communication and data visualization, and providing empirical data to support and inform resource management. Dr. Corey Phillis, lead author of the study, can also be found in the twittersphere as @hydrophillis

 Further reading

Phillis CC, Sturrock AM, Johnson RC, Weber PK. 2018. Endangered winter-run Chinook salmon rely on diverse rearing habitats in a highly altered landscape.  Biological Conservation 217: 358-362.

Moyle PB and Lusardi RA. 2017. Moving salmon over dams with two-way trap-and-haul.

California Trout and UC Davis Center for Watershed Sciences. 2017. State of the Salmonids: Fish in Hot Water

Posted in Biology, Fish, Salmon | Tagged , | 4 Comments

Beginning of 2018 drought? – December 31, 2017

High and prepip lows for California December 2017

by Jay Lund

Every year is different for water management in California.

The 2012-2016 water years were among the driest and warmest on record.  2017 was the wettest year of record for much of California, with thousands of water managers struggling to store as much water as possible in reservoirs and aquifers.

So far for this 2018 water year (which began October 1), Northern California precipitation is about 67% of average for this time of year.  Further south, the San Joaquin Basin precipitation is about 38% of average and Tulare basin is about 25% of average.  Snowpack statewide is about 27% of average for this time of year.

December has had essentially no precipitation and a stationary ridge in the Pacific Ocean off California seems likely to block most moisture from the Pacific Ocean into January.

Fortunately, today California has 109% of average water storage in reservoirs for this time of year, 1.5 maf more than average reservoir storage.  The wet 2017 water year substantially refilled Northern California’s less depleted aquifers.  But only a small part of the additional drought groundwater withdrawals has been recharged for the more depleted aquifers of the southern Central Valley and southern California.

Here is some simple statistical analysis on three reasonable questions.

1) Will the 2018 water year be dry? Likely, but maybe not.

Let’s look at some historical statistics of monthly precipitation in Northern California.

For the last 97 years, when December precipitation was in the lowest 20% of all years, 79% of the overall water years were drier than the median precipitation.  As the plot below summarizes, the dry December likely means a drier year, mostly because the annual total is deprived of December precipitation, but also because there is also some correlation that drags down precipitation in other months.  From the regression equation slope, one inch loss of December precipitation averages 1.28 inches in lost annual Northern California precipitation.  One inch less December precipitation tends to be accompanied by an additional 0.28 inches of less precipitation in other months.  So there is a good chance that 2018 will be drier than the median and drier than average.

However, of the 19 historical years with the driest 20% of Decembers, four had total precipitation above the 97-year median.  So there is roughly a 21% chance that 2017 will be an above-median water year.

December vs Water Year Precip for N Cal

2) What about floods? Does a dry December reduce the probability of flooding this year?  Yes, but a flood could still occur.

A review of Northern California precipitation statistics shows that in 97 years, years when December has been in the lowest 20% of precipitation have never had flood levels of precipitation (more than 20 inches, corresponding to the 16 wettest months since 1921).  Part of this is that a dry December means that one of the most flood-prone months did not have a flood.  But a flood could still happen January through March.  Viewed this way, the odds are low that 2018 will be a flood year – But water managers probably should not bet anyone’s flood safety on this statistic.

3) If 2018 is a dry year, is it the beginning of a new drought for California?  Perhaps not.

With its long dry summers, every year California has a worse drought than most of the US has ever seen.  This troubled early settlers, but today California’s city water supply and irrigation systems have enough reservoir and aquifer storage, supply interconnections, and institutional responsiveness so that most economic water uses are largely immune from one-year droughts. (Ecosystem impacts are a sadder story, however.)

California almost has to have at least two dry years together for there to be a noteworthy drought.  Even if this year is dry, there is only about a 50% chance that the next year is drier than the median.  Total water year precipitation has very little correlation between years, as seen in the two figures below.

Looking at the statistics for Sacramento Valley runoff (since 1906), by definition half of these 111 water years (55 years) are drier than the median.  Thirty years are in the second or more year of successive dry years.  18 years are in the third or more consecutive dry years, 10 years are in the fourth or more consecutive dry year, 4 are in the fifth of more consecutive drier than median year, and 2 years are in the sixth consecutive drier year.  No historical droughts exceed six consecutive drier years.

Progression of dry years in Sacramento Valley

The frequency of longer drought years declines almost as if there were no correlation for dry years.  This is shown more formally below, which plots annual Sacramento Valley runoff against the runoff in the previous year.  There is a roughly 10% correlation in annual runoff, which explains about 1% of variance in annual runoff (some, but not much).

Annual runoff correlation for Sacramento Valley

Bottom line – California’s 2018 water year will likely be drier than the median year, and still more likely to be drier than the average year.  It could still be wet, but is less likely to have a major flood.  However, floods are dangerous enough and still likely enough that it would be unwise to not prepare and operate for floods as well.

Although we would like to predict California’s hydrology for the coming season and years, we unlikely to have great skill in this – perhaps ever.

Further Reading

CDEC, The mighty California Data Exchange Center,

Lund, Jay (2015), “The banality of California’s ‘1,200-year’ drought,”, September 23.

Null, Jan (2017), “Dismal Beginning to SF Rainfall Season”, Golden Gate Weather Services Weather and Climate Blog, posted December 21, 2017

Swain, Daniel (2017), “Strikingly dry conditions persist; Thomas Fire now largest California wildfire,” December 24, 2017,

Swain, Daniel (2017), “New insights into the Ridiculously Resilient Ridge & North American Winter Dipole,” December 4, 2017,

Fun statistical fact (for geeks who read to the bottom)

Most years are drier than average.  In the historical record of Sacramento Valley unimpaired flow, 57% of years are drier than average.  Why? Averages are increased by very wet years, which do not affect the median flow (50% above and 50% below). Because precipitation and flow usually can’t be less than zero, extreme dry years cannot pull the average down as much as extreme wet years pull the average up.  This skews their probability distributions away from zero, with more than 50% of years being drier than average.  (But you already knew that water in California is not normal.)

Jay Lund is a professor of Civil and Environmental Engineering and Director of the UC Davis Center for Watershed Sciences.

Posted in California Water, Drought | Tagged | 5 Comments

Nudging progress on funding safe drinking water

by Jay Lund

9-year-old Carlos Velasquez drinks well water from a hose at a trailer park near Fresno, Calif. In 2015, residents of the trailer park received notices warning that their well water contains uranium at a level considered unsafe by federal and state standards. (AP Photo/John Locher)

This year’s Nobel Prize in Economics went to Richard Thaler, who pioneered “nudging” to help people volunteer to make more personally and socially beneficial decisions.  As an example, having employees automatically enrolled for retirement contributions and then allowing them to lower their contributions results in considerably more retirement savings than having them “opt-in” to retirement contributions with no default contributions.  Similarly, informing water users that their water use substantially exceeds their neighbors significantly reduces their water use.

Can such Nobel ideas help with some of California’s water policy problems, such as providing financial support for safe drinking water in rural communities?

Today California has about 200,000 people, mostly in rural communities, who lack access to safe drinking water mostly due to contaminated or dry wells.  Agricultural nitrate contamination of aquifers in the Tulare and Salinas basins alone costs small drinking water systems roughly $40 million per year.  A host of natural and other contaminants impact many small systems.  Small communities often lack the economies of scale needed to keep costs affordable for the poor.

Funding safe drinking water in small, rural communities is a major problem, given their inherently higher costs, often made higher by external contamination, falling groundwater levels, and unavoidably small revenue base.

Everyone has an interest in safe drinking water everywhere.  We each have an economic interest in eliminating the economic drag of unsafe drinking water on the overall economy, and in poor communities in particular.  Morally, a society has some obligation to protect the health of its members. And we all have a personal interest in being able to travel throughout California without fear of drinking water. So presumably we all have some willingness to pay for such water security.  In telecommunications, we all pay a small additional charge to support more universal phone service for the poor.  But so far such broad sentiments have not led to long-term support for safe drinking water in disadvantaged drinking water systems.

Part of the water pipeline for Seville, California, runs through an irrigation ditch. The water system has had problems with bacterial contamination and aging infrastructure, creating water quality concerns for the community. (Tara Lohan, Water Deeply)

The last legislative session almost saw a funding package for safe rural drinking water (SB623). The legislation would have taxed fertilizer sales at 0.5% and a dairy production tax of about 0.1 cents per gallon to raise about $30 million per year.  The bill would also curtail State Water Board’s enforcement of some clean water regulations on agricultural nitrate contamination.  Urban water users would be taxed at $11.40/year for residential connections and higher rates for larger business connections to provide about $110 million per year.  These funds would be administered by the State Water Board to “secure access to safe drinking water for all Californians.”  The legislation was supported by agricultural and environmental justice advocates, but was killed by opposition from urban water agencies.

California has several public goods that might be partially funded in a responsible way with a modest surcharge on water rates. Much like telephone surcharges that subsidize service for the poor, a water surcharge can support safe drinking water for the poor, which benefits all.  A surcharge on water rates could also help fund support for native ecosystems, which have suffered in part from water diversions and infrastructure.

Water agencies are understandably reluctant to set precedence for such surcharges, which could lead to ever larger taxes on water use whenever advocates for the poor, the environment, or other causes feel they need more money.  (Somehow, everyone always feels they need more money.)

Perhaps a nudge can help overcome this public finance gridlock, raising funds to help with public goods while encouraging continued public support for such funds.

A partially voluntary public goods charge for safe drinking water

Funding to help struggling rural water systems might combine small, mandatory charges with larger, voluntary, nudge charges for residential customers. Such charges might include:

1. Urban safe water connection fee, with three parts.  For revenue estimation, assume 7 million residential and 1.2 million commercial urban water supply connections.  Making part of a funding system voluntary creates an incentive for transparency, participation, and documentation of effectiveness.

1a. Mandatory safe water connection fee of 30 cents per month on all public water system connections, raising $30 million per year.

1b. Mandatory commercial safe water connection fee of 60 cents per month, raising $8.6 million per year.

1c. Voluntary urban safe drinking water connection fee of 60 cents per month on every residential connection, raising a maximum of $50 million per year. This voluntary fee would be charged by default, with residential users able to reduce their contribution to a lower level or entirely.  This should eliminate many objections to such a public goods charge and provide incentive for benefiting programs to demonstrate their ongoing value.

A charge based on volume of water use might increase incentive to conserve water, but a per-connection charge is easier to administer and might better align with the idea of individual households supporting safe drinking water for all.

2. Nitrogen fertilizer and dairy production taxes to raise $40-60 million per year. This would be mandatory and largely provide a means of compensating for agricultural damage to rural drinking water systems. (The proposed fees would be a bit higher than those recently proposed to be in line with independent estimates of the costs of addressing water quality damages.)

Total revenues from this package would be similar to the proposed legislative package, but without many of the concerns for the previous legislation.

Much of the problem with a public goods charge is concern that the monies raised will be spent well.  Nudge-based funding has some advantages in this regard. Benefiting programs have an incentive to be publicly cost-effective, so contributors don’t reduce their contributions.  Further public support might arise from adding a regional focus on expenditures, such as requiring that 70 percent of revenues be spent within the region where they are raised, perhaps overseen by the Regional Water Quality Control Board.  This would allow 30 percent to be used for safe drinking water supplies elsewhere in California.

This idea is not a funding panacea for water-related public goods.  It might raise less money than the earlier proposed legislation, but it might raise more. More importantly, it would raise funds in a way that builds public support and confidence in safe drinking water everywhere and perhaps ultimately for ecosystem management as well.  Nudging might help public utilities and their customers to form effective partnerships to support the broader public interest of ratepayers and utilities alike, draw people’s attention to these purposes on their water bills, encouraging water conservation, and making it easier for good citizens to contribute to the public good.

We all have an interest in contributing something to safe drinking water for everyone in California.  Perhaps such sentiments can be mustered and partially monetized in voluntary, as well as mandatory, ways to help solve a fundamental public health and economic problem for poor communities.

Further reading

Thaler, R.H. and C,R. Sunstein (2008). Nudge: Improving Decisions about Health, Wealth, and Happiness Yale University Press, 2008.

Murphy, K., “First-ever water tax proposed to tackle unsafe drinking water in California,” The Mercury News, San Jose, CA, August 23, 2017.

SB623 language –

Lohan, T. Unlikely Allies Push Bill to Solve California Drinking Water Crisis, Water Deeply, July 27, 2017.

Harter, T., et al. Addressing Nitrate in California’s Drinking Water with a Focus on Tulare Lake Basin and Salinas Valley Groundwater. Report for the State Water Resources Control Board Report to the Legislature. Center for Watershed Sciences, University of California, Davis. 78 p., 2012.

Posted in California Water, Drinking water, Nitrate, Sustainability, Uncategorized, Water Supply and Wastewater | Tagged , | 3 Comments