Providing Flows for Fish


Putah Creek below Putah Creek Diversion Dam, December, 2014, a drought year.  The stream flows are regulated in part to support a diverse native fish fauna, including Chinook salmon.

by Peter Moyle

A reality in California and the American West is that people are competing with fish for water. We humans are winning the competition.  However, because there are moral, aesthetic, and legal obligations to provide fish with water in streams, biologists like me often get asked the question “Just how much water do the fish need, anyway?” This, of course, is the wrong question because the best reply is  “all of it!” if you consider the stream flows under which each fish species evolved, that often varied from raging torrents to gentle summer trickles across a single year.   The question may then switch to, “well, what is the minimum flow we need to provide to keep the fish alive?”  This is also the wrong question because if you keep a stream fish assemblage on minimum flows for a long enough period, most native species will likely disappear. In their place will be trout raised in hatcheries and non-native species like fathead minnows and green sunfish; these fish will live in a highly degraded habitats, signified by dead riparian trees and stagnant pools. A more useful question is “what is the optimal flow regime that will allow a diverse native fish fauna and other biota to thrive, while providing water for use by people?”

Attempts to find an answer to the last question, usually by simple, cheap hydrologic methods, have dominated stream flow disputes over fish for decades.  While some regions now typically use holistic approaches, in the USA and few other countries there remains heavy reliance on mechanistic approaches such as the Instream Flow Incremental Methodology (IFIM) and its modeling companion PHABSIM.  Frankly, these methods don’t work very well, because they are based on some untenable assumptions and on simplified models that bear little resemblance to ecological reality. Without trying to explain them further, lets just say they are likely to work best in a ditch that contains only rainbow trout.  So what does work for most streams?  There are several good options, which are explained in a new book Environmental Flow Assessment : Methods and Applications by John Williams,  Peter Moyle, Angus Webb, and Mathias Kondolf (2019, Wiley Blackwell, 220 pages).  You will note that I am a co-author so you may want to read this summary with some skepticism.


It is not by accident that the two chapters of the book following the introductory chapters are primers on flow and life in rivers and streams.   These chapters make the point that flowing waters are beautifully complex both physically and biologically, so it is rather naïve to think that a simple hydrologic model will suffice to determine flows needs for desirable aquatic life  (or even just fish).

The next chapter (5) deals with tools for environmental flow assessment (EFA). It shows that we don’t have to be content with standard hydrologic models because there are so many options these days, of intellectual tools, models, concepts and approaches that be used for EFA. Examples of new approaches to EFA that the book describes include Bayesian networks and hierarchical Bayesian models, of growing interest in biological systems.  Of course, tools are only as useful as the users make them.  “Ultimately, successful EFA depends on clear and critical thinking; the human brain is the most important tool for environmental flow assessment (p. 51).”

Once the myriad of tools available for EFA are in hand, there are many options for methods to determine environmental flows. Chapter 6 classifies these options and provides a critique of how and when each one is useful; the methods range from very simple to very complex. Any of them can be misused, of course, but most methods, preferably holistic ones, can be adapted to local situations.  The latter is important because no two streams are exactly alike so when a study is proposed, diverse options should be considered.

This is also true for the use of models in flow assessment, which seem ubiquitous. They are often used as if they can, by themselves, provide definitive solutions to a flow problem.   Because of this, the book (Chapter 7) provides a lengthy discussion on modeling and model testing.  It‘s the kind of background we hope everyone involved in an EFA relies on from the beginning. But the most basic lesson here is that: “Models are best used in EFA to help people think, not to provide answers (p. 141).”

Nowhere in the EFA universe are models more important than when looking at the how rivers are regulated below dams. Indeed, most EFAs are done on regulated streams.  Historically, most EFAs were couched as water vs fish, with little attention paid to inevitable geomorphic simplification of fish habitat that dams cause. Dams reduce sediment inputs, stabilize stream channels, and eliminate most high flows events. These processes are important for allowing stream channels to support diverse riparian and aquatic habitats for fish and all other aquatic life (Chapter 8).  Maintaining a ‘living stream’ below a dam is hugely challenging, but possible if an adaptive attitude is maintained towards EFMs.

Much of the book is critical of common methods for EFA. However, Chapter 9 presents a highly workable approach for the typical case where limited data are available, so expert opinion becomes more important for developing a flow regime that favors desirable species, usually fish.  The trick is to use structured methods to turn expert opinions (including those from published papers and reports) into a conceptual model of the situation. The conceptual model can then be quantified as a Bayesian Network Model. This model can be continuously improved as more data becomes available.  Ideally these data would be collected from the stream being modeled, by monitoring the effects of an initial flow regime. This results in a ‘feed back loop’ of more data making the model more useful followed by further manipulation of the study stream.  Eventually, the greatly improved data set will allow a more powerful Bayesian hierarchical model to be used.

The final chapter is short but contains the statement  “We have also emphasized that EFA is human activity and so subject to human behavior.”   This idea should be kept mind even when evaluating abstract hydrologic models. The book ends with a long checklist of things to keep in mind when conducting an EFA.

Because the book is aimed a broader audience than the people who just conduct EFAs, we made an effort to keep the language as concise, jargon–free and as clear as possible, given our own deep interests in the issues. In fact, clear writing is key to good EFAs, especially plain-word summaries of technical reports.

It is hard to over-emphasize the need for improved and innovative assessments of environmental flows in California’s streams, because there are over 1400 large dams in the state. Most dams need periodic reassessment of their flows for aquatic life, especially fish.  Climate change, with longer droughts and bigger floods, will create more disputes over managing the limited water supply. Improved understanding of the EFA options available should make settling such disputes in an amicable fashion more likely.

Further reading

Williams,  J., P. Moyle, A. Webb, and M. Kondolf (2019), Environmental Flow Assessment : Methods and Applications (Wiley Blackwell, 220 pages).




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The Good, the Bad, and the Ugly of California’s State-Mandated Urban Water Conservation during Drought

Drought face 1by Amy Talbot

Amy Talbot is the Regional Water Efficiency Manger for the Regional Water Authority, which represents 21 water suppliers in the Sacramento region.  She manages an award-winning public outreach and education program.  Additionally, she is a board member of the California Water Efficiency Partnership (CalWEP), which is supporting water suppliers with the implementation of Senate Bill 606 and Assembly Bill 1668. This blog post is based on her MA thesis, both of which solely represent her personal opinions and may not be attributed to the Regional Water Authority or its member water suppliers or the California Water Efficiency Partnership or its members.

Historic 2014 weather and water supply conditions prompted Governor Brown to order the state’s first mandated conservation targets for over 400 urban retail water suppliers starting in 2015.[1]  Governor Brown tasked the State Water Resources Control Board (SWB) and the California Department of Water Resources (DWR) to manage and enforce these mandates.  With a 25% statewide water use reduction goal, state agencies, water suppliers, media, businesses, and residents worked together to implement supply and demand side actions to limit water use.  The state met this goal, reducing urban use by 24.5% from June 2015 through May 2016 equating to 524 billion gallons (1.6 million acre-feet) compared to 2013 water use.[2]  The state’s drought response was seen by some as an overwhelming success and by others as an unprecedented, and possibly illegal, invasion of local water suppliers’ management of their water supplies, water systems and relationships with their customers.  Regardless of perspective, it was uncharted territory, with new policies introduced in a short time with varying benefits and some unexpected consequences.  Through analyzing the practical outcomes of the state’s drought response, the overall experience can be distilled into what worked and what didn’t.

What Worked:

  • Prioritizing outdoor water use conservation over indoor conservation: Public outreach messaging focused on outdoor water use, which can be reduced quickly, with significant savings in most areas, while protecting indoor uses that support public health and safety.
  • Consistent water supplier reporting: Monthly reporting by water suppliers to the state allowed for real time monitoring to assess current water demand conditions and provided public transparency on water use.
  • Greater drought awareness: The state, the media, businesses, and residents maintained widespread attention on the drought, which prolonged water savings.
  • Water supplier coordination: Water suppliers found commonality through shared conservation targets and kindred feedback to the state on proposed regulations. Furthermore suppliers shared, exchanged, and coordinated public outreach campaigns and programs to more effectively respond to drought.

What Didn’t Work:

  • Conservation targets neglected water supply adequacy: Mandated water use based conservation targets did not directly respond to local water supply shortages.
  • Lack of optimization of alternative supplies and markets: The state’s drought response approach did not substantially consider local water suppliers’ prior investments in drought-resistant supplies and planned drought responses and therefore, at times, reduced local suppliers’ ability to respond with non-conservation water supply actions during drought, such as short-term or long-term water purchases, use of groundwater in storage, etc.
  • Ineffective communication: Communication breakdowns during the drought between state agencies, water suppliers, and customers complicated public outreach messaging aimed at reducing water use. One example is the use of the U.S. Drought Monitor to convey state and local water supply and drought conditions.
  • No regional compliance option: The initial rejection of a regional compliance option to meet state conservation mandates reduced incentives for local agencies to collaborate regionally.

Near the end of the mandated conservation target period, Governor Brown issued an Executive Order (EO) titled “Making Water Conservation A California Way of Life.”  Several concepts in the EO were incorporated into Senate Bill (SB) 606 and Assembly Bill (AB) 1668, which were passed in May 2018.  These bills will establish new local water supplier water efficiency targets based on indoor and outdoor residential water use, commercial, industrial, and institutional landscape water use, and water lost through leaks.  The bills will also increase supplier drought planning efforts through an expanded 5-year drought planning timeframe and statewide standard stages and percent reductions for urban water suppliers’ water shortage contingency plans.

Over the next decade, the state, urban water suppliers, businesses, and residents will implement this legislation, effectively redefining water efficiency and drought management planning in California.  The stakes are high with pending financial, staffing, policy, and infrastructure impacts for retail urban water suppliers and tight timelines for the state to finalize regulations before suppliers begin reporting in 2023.  Below are some recommendations for the successful implementation of SB 606 and AB 1668 and improved drought response in California.

Recommendations for Senate Bill 606 and Assembly Bill 1668 Implementation:

  • The state should clarify its statewide water saving goal and objectives: SB 1668 states that the water savings from the new regulation “would exceed the statewide conservation targets required”, meaning it would exceed the target of a statewide 20% reduction in urban use by 2020 established by 2009’s Senate Bill X7-7.  However, not all water suppliers under the current statewide conservation targets are required to save exactly 20% – targets vary up to 20% depending on several factors. Is the new savings goal to exceed targets at the statewide level or by each individual supplier?  What is the baseline used to calculate this new savings?
  • Outdoor water use reductions should be moderate: The state heavily focused on reducing outdoor watering during the recent drought. While widely accepted in a drought emergency, continuously reducing landscape water use beyond levels of efficiency can harm other landscape functions like providing habitat, healthy soil, quality of life benefits, tree health, and stormwater management.
  • State driven water efficiency efforts should match expected savings: Is the “juice worth the squeeze” for these regulations?  The resource commitment (staff and funding) needed to implement complex local supplier water budget targets should not exceed potential benefits from the anticipated water savings.
  • Energy efficiency funding should supplement water efficiency program budgets: As shown during the drought, water savings also produced energy savings, sometimes more cost-effectively than standard energy efficiency programs (Spang et al., 2018). Local water and energy suppliers should continue to work together towards mutual resource savings goals.
  • The state should allow a compliance target range for urban water suppliers: With many data-based details and potential for error in the designing and implementing of these new regulations, the state should allow flexibility in enforcement of the urban water supplier targets.

Recommendations to Improve Drought Response:

  • Drought water use reductions should be linked to local water supply conditions: Drought is ultimately a local condition and water suppliers respond to the risk of it by investing in water supplies and other measures that are available locally. Perhaps the biggest misstep from the 2014-2016 drought was the initial state-mandated conservation targets based on water use, not water supply.
  • Residential lawns should be water conservation reserves in future droughts: Collectively, lawns throughout a water supplier’s service area could be tapped to reduce residential water demand rapidly by up to 50% in some areas of the state. No other single action can deliver this reduction short of cutting off service or risking public health.
  • Urban water suppliers should have approved drought revenue recovery mechanisms compliant with Proposition 218 as part of their standing policies and rate structure: Water suppliers should not be required by the state or any other entity to trigger this mechanism, but a revenue recovery option should be readily available to suppliers in the event of supply interruptions due to drought or other reasons. 
  • Drought management should be controlled locally, coordinated regionally, and overseen at a state level: State and regional actions should not disrupt suppliers from investing in reliability planning; instead, the state should recognize the local, regional, and statewide benefits of reliability investments. Local water suppliers should maintain their own policies and drought response plans.
  • Local, regional, and state entities should work more closely with media outlets to accurately report water related information: Staff at all three levels should have media training, updated communication plans, and media talking points/messaging available to facilitate ongoing relationships with local media.  Water savings during drought largely depends on customer actions (or inactions) supported and communicated by statewide, regional, and local media reporting, local water suppliers, and other public outreach efforts.
  • Rebate programs should be less prominent during drought: Generally, rebate programs create limited direct water savings during droughts, but expend significant staff time and funding. During drought, water suppliers should prioritize broader public and media outreach focused on reducing outdoor water use.

The SB 606 and AB 1668 recommendations would increase the prominence of water efficiency in the state and nudge it closer to where it belongs, towards deeper, and in some cases equal integration with other resource management actions like supply augmentation.  The days of conservation and efficiency programs being thought of as “stickers and bubblegum” are behind us.  In the absence of implementing these recommendations, SB 606 and AB 1668 could be implemented in ways that deter improving overall efficiency through superfluous and ineffective requirements that become more of a burden than a valuable investment.  The drought response recommendations seek to smooth over some of the harsher edges experienced in the last drought and improve response to the next drought.

In the meantime, debates over how to manage water in California will continue at all levels.  The state and water suppliers will keep trying, working toward their own solutions in coordination with others.  It is a give and take, a push and pull, even a power struggle at times that shapes and advances water efficiency within overall water management.  It’s both frustrating and fascinating.  It could not be any other way.

Final Thought:

“Unfortunately, we tend to focus on drought when it is upon us. We’re then forced to react — to respond to immediate needs, to provide what are often more costly remedies, and to attempt to balance competing interests in a charged atmosphere. That’s not good policy. It’s not good resource management. And it certainly adds to the public’s perception that government is not doing its job when it simply reacts when crises strike. To the contrary, we must take a proactive approach to dealing with drought. We must anticipate the inevitable — that drought will come and go — and take an approach that seeks to minimize the effects of drought when it inevitably occurs.” — James R. Lyons, Assistant Secretary of Agriculture for Natural Resources and the Environment, speaking at Drought Management in a Changing West: New Directions for Water Policy, in Portland, Oregon, in May 1994.

Drought face 2
Further Reading and Resources

Talbot, Amy.  (March 2019).  “Urban Water Conservation in the Sacramento, California Region during the 2014-2016 Drought.”  Master thesis in Geography, University of California, Davis.

State of California.  (April 2017). “Making Water Conservation a California Way of Life: Implementing Executive Order B-37-16.”  Final Report.

Brown, Edmund G. (May 2016).  “Executive Order B-37-16: Making Water Conservation A California Way Of Life.”

State of California. (2018). “Making Water Conservation a California Way of Life: Primer of 2018 Legislation on Water Conservation and Drought Planning Senate Bill 606 (Hertzberg) and Assembly Bill 1668 (Friedman).”

California Department of Water Resources (DWR). (2019). “Making Conservation A Way of Life.”  Webpage.

Mitchell, David, Hanak, Ellen, Baerenklau, Ken, Escriva-Bou, Alvar, Mccann, Henry, Perez-Urdiales, Maria, & Schwabe, Kurt. (2017).  “Building Drought Resilience in California’s cities and suburbs.” Public Policy Institute of California (PPIC).

California Department of Water Resources (DWR). (May 1978).  The 1976-1977 California Drought: A Review.

California Water Efficiency Partnership (CalWEP). (2019). “Framework Compliance.” Webpage.

Spang, Edward S., Holguin, Andrew J., and Loge, Frank J.  (January 12, 2018). “The estimated impact of California’s urban water conservation mandate on electricity consumption and greenhouse has emissions.” Environmental Research Letters, Volume 13, Number 1.

Feinstein, Laura, Phurisamban, Rapichan, Ford, Amanda, Ford, Christine, and Crawford, Ayana. (January 9, 2017). “Drought and Equity in California.” Pacific Institute.

Seapy, Briana. (March 2015).  “Turf Removal & Replacement: Lessons Learned.” California Urban Water Conservation Council.

End Notes

[1] “Urban retail water suppliers” are either public or private owned, providing water for municipal purposes directly or indirectly to more than 3,000 customers or supplying more than 3,000 acre-feet of water annually.  (California Water Code Section 10617).

[2] June 2015-May 2016 represents the timeframe for the state’s mandatory conservation targets for urban retail water suppliers.  Source: State Water Resources Control Board (SWRCB). (July 6, 2016). “Emergency Water Conservation Regulation Update-Office of Research, Planning, and Performance.”  Staff Presentation.


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Who governs California’s drinking water systems?

By Kristin Dobbin and Amanda Fencl

A key feature of California’s drinking water system is the large number of individual water systems. There are approximately 3,000 Community Water Systems (CWSs) in the state, meaning systems that serve a residential population year-round (the remaining 5,000 of the state’s 8,000 Public Water Systems are non-community systems serve places like schools, daycare, hospitals, campgrounds, or businesses that serve at least 25 people but have transient or non-residential populations. Additionally there are an unknown number of unregulated water systems in the state that do not meet the 25 person or 15 connection size threshold for regulation under the Safe Drinking Water Act. This extreme decentralization and fragmentation of governance results from local land use decisions, politics and a preference for local control by the state and locals. While allowing for local control and flexibility, this arrangement has not guaranteed safe drinking water for all (NYT 2019; Politifact 2019; SacBee 2018). More than a million Californians lack safe water, primarily in low-income communities, communities of color, indigenous communities and rural communities.

Particularly for CWSs, governance is critical to resolving the crisis (Wutich et al. 2016; Newig and Fritsch 2009). The number of systems and diversity of structures under which they operate, however, is a challenge for policy and practice. For system consolidations, for example, solutions need to be developed and implemented with explicit consideration for how system governance affects representation and accountability (Nylen, Pannu, & Kiparsky 2018). And in newly formed Groundwater Sustainability Agencies, disadvantaged communities without CWSs that are public agencies (e.g., mutual water companies) are significantly less likely to be represented as decision-makers (Dobbin and Lubell 2019). Better understanding the existing landscape of CWSs in California is key to understanding how governance can address the entrenched disparities.

An important first step in this direction is to identify and analyze the range of CWS governance arrangements. To do so, we coded each of the 2,895 active CWSs in the state as of the end of 2018. Where possible, we relied on standardized names reflecting specific public district types (e.g. Community Services Districts, County Service Areas), and where not, we employed Consumer Confidence Reports, websites, tax filings and general Google searches using the system’s name and location to identify its specific organization types such as Mutual Water Companies or Property Associations. We also cross-referenced our data with existing lists such as the Public Utility Commission’s list of Investor-Owned Water Utilities. Ultimately, we identified 26 distinct system types as defined by a system’s legal structure/derived authority, who operates it and/or who it serves. These 26 types are aggregated into nine governance categories and classified as either publicly or privately owned entities. The table below summarizes these findings.

Table 1. Breakdown of California’s Community Water Systems by governance category and type

  # of CWSs Median population served # of
CWSs w/ violations
Average # violations per CWS*
All CWSs  (PWS with > 15 connections or 25 people) 2,895 287 854 2.27
Publicly Owned CWSs 1,166 2,984 295 1.92
City: City (315); Special Act District (2) 317 22,795 80 1.43
County Service Area (77); Maintenance District (46); County Waterworks District (27); County Sheriff (12); County Dept. (excluding sheriff) (11); Special Act District (8);
Resort Improvement District (2)
183 350 55 3.08
Joint Powers Authority 12 109,254 0
Independent Special Districts:
Community Services District (185); County Water District (165); Public Utility District (53); Irrigation District (51); Special Act District (34); California Water District (32); Municipal Water District (31); Sanitary District (6); Municipal Utility District (3); Water Conservation District (3); Resort Improvement District (2); Resource Conservation District (1)
566 1,885 132 1.8
State and Federal: Federal (38); State (50) 88 2,200 28 2.36
Privately Owned CWSs 1729 126 559 2.51
Investor Owned Utility 220 1,695 39 1.49
Mobile Home Parks 375 108 124 2.3
User Owned Utilities

Mutual Water Company (582);
Property / Homeowners Associations (70)

652 124 218 2.34
Other private systems 482 79 178 3.36
*SDWA violation data was calculated by combining two data sources. The first is 2012- 2018 documented health-based violations from the State Board’s Human Right to Water portal, which excludes total coliform violations (SWRCB 2018). Because of this exclusion, we added Total Coliform Rule (TCR) health-based violations for each system from the SDWIS federal reports database (EPA 2019). When combined, the total number of CWSs with > 1 violation jumps from 525 to 854. The average number of violations per system in the last column is the average across all systems in each governance category.

From this analysis, four findings stand out:

1. There is considerable diversity in governance structures among CWSs, with greater diversity for public and small systems. As previously mentioned, we identified 26 distinct governance types among the 2,895 CWSs. Public CWSs make up 21 of these types, including 12 distinct types of independent special districts. Two types, Special Act Districts and Resort Improvement Districts appear in multiple governance categories because their enabling legislation set forth different options for composing their governing boards. The most frequent types of public systems are cities (315), Community Services Districts (185), and County Water Districts (165). There are five types of privately owned CWSs, including a catch-all category for “other private” systems representing for-profit, not-investor owned systems that we were unable to further disaggregate. Mutual Water Companies are the most common type of private CWS (582), followed by “other privates” (482), and mobile home parks (375). Using the median population served to classify each type as being comprised of either predominantly small (< 10,000 people served) or large ( > 10,000 people served) systems. Five types are predominantly large systems: Water Conservation Districts, Joint Powers Authorities, Resource Conservation Districts, Municipal Water Districts and Cities. The remaining twenty-one types are predominantly small systems.

Fig 1


2. System ownership and size are inversely related. While Most Californians (95%) get their water from 475 systems that are large (30%) or very large (65%), most (84%, 2,420) of California’s CWS serve less than 10,000 people. These smaller systems are responsible for drinking water provision to approximately 2.3 million people. 68% of such systems are privately owned (n=1,644), compared to just 18% of larger systems (n= 82).

Fig 2


3. Overall, around one-third of systems in the state have had a health-based violation in the last 7 years, but these incidents are not evenly spread across all governance categories. California’s CWSs have an average of 2.27 violations per system between 2012 and 2018. More information, however, can be gained by summarizing violations by governance category as we do in the table above. Excluding Joint Powers Agreements, where all twelve systems had zero violations, cities have the lowest average, just 1.43 violations per system over the seven years. In comparison, “other private” systems had an average of 3.36 violations followed by county operated systems with an average of 3.08 per system.

4. Health-based violations incidents are also not evenly spread across all system sizes in the last 7 years. As other studies have consistently shown, smaller systems have a harder time delivering safe water. Small and very small systems account 76% of all CWSs and 88% of the total violations in the data. Looking just at the 1,732 very small systems serving less than 500 people, five governance categories, on average, all have more violations than the statewide average: County (4.03), “other private” (3.6), Investor Owned Utilities (2.54), User Owned Utilities (2.51), and Mobile Home Parks (2.35).

Kristin Dobbin is a PhD student in Ecology at UC Davis studying regional water management and drinking water disparities in California. Amanda Fencl recently completed her PhD in Geography at UC Davis and is now a Postdoctoral Research Associate at Texas A&M University.

Further Reading

Nylen, Pannu & Kiparsky (2018). Learning from California’s Experience with Small Water System Consolidations: A workshop synthesis. Center for Law, Energy and the Environment, UC Berkeley.

McFarlane, K., & Harris, L. M. (2018). Small systems, big challenges: review of small drinking water system governance. Environmental Reviews, 26(4), 378-395. DOI: 10.1139/er-2018-0033.

Teodoro, M. (2019). Grow to Shrink, Shrink to Grow. June 27, 2019.

London et al. (2018)  The Struggle for Water Justice: Disadvantaged Unincorporated Communities in California’s San Joaquin Valley.  Center for Regional Change, UC Davis.

Pannu (2012) Drinking Water and Exclusion: A Case Study from California’s Central Valley. 100 Calif. L. Rev. 223.

Ekstrom et al. (2018)  Drought Management and Climate Adaptation of Small, Self-Sufficient Drinking Water Systems in California. California’s Fourth Climate Change Assessment, California Natural Resources Agency. Publication No. CCCA4-CNRA-2018-004.

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Remarkable Suisun Marsh: a bright spot for fish in the San Francisco Estuary

Picture 1 suisun blog

by Teejay O’Rear and Peter Moyle

To most people, Suisun Marsh is either the seemingly blank area visible at 70 MPH from the north side of Highway 680 or the sudden expanse of tules visible after the Amtrak train leaves Suisun City, headed for Oakland. However, it is one of our favorite places in California, where it is easy to imagine being in a different place and time, with sturgeon jumping out of the water; flocks of ducks, ibis, and pelicans flying overhead; otters swimming by; and tule elk coming down to the water’s edge for a drink.  We know the marsh well because we have been taking a boat out every month to sample its fishes.  This sampling started 40 years ago, when Peter Moyle and a graduate student, Don Baltz, did some trawling in the marsh to look for tule perch and learned it supported many fish of all sorts.  Here we provide an updated account of Suisun Marsh fishes to show why the marsh is so important for conserving fishes in the upper San Francisco Estuary in general…and why we continue to be enthusiastic about working there.

Suisun Marsh is a brackish-water marsh bordering the northern edges of Suisun, Grizzly, and Honker bays in the San Francisco Estuary; it is the largest uninterrupted estuarine marsh remaining on the western coast of the contiguous United States. Much of the marsh area is diked wetlands managed for waterfowl, with the rest consisting of tidal sloughs, marsh plains, and grasslands. The marsh’s central location in the northern San Francisco Estuary makes it an important habitat for diverse freshwater, estuarine, and marine fishes.  The marsh also is a migratory corridor for anadromous fishes such as Chinook salmon and striped bass.

Pic 2 suisun

Suisun Marsh (map by Amber Manfree).

The protection of Suisun Marsh was specifically written into the bill creating the State Water Project, mainly to ensure that waterfowl populations would not be harmed by increased diversions of fresh water.  Fish were also part of that protection, so in January 1980, the Department of Water Resources contracted with UC Davis to monitor fish populations in the marsh. The result was our Suisun Marsh Fish Study, which has consistently used beach seines and otter trawls to sample juveniles and adults of all species since the study’s inception.  The primary objectives of our study have included (1) evaluating effects on fishes of the Suisun Marsh Salinity Control Gates, which began operating in 1988; (2) examining long-term changes in Suisun Marsh’s ecosystem relative to other changes in the San Francisco Estuary; and (3) enhancing understanding of the life history and ecology of key species in the marsh.  Secondary objectives have included supporting research by other investigators through special collections; providing background information for in-depth studies of other aspects of the Suisun Marsh aquatic ecosystem, such as the feeding ecology of jellyfish; serving as a baseline for restoration projects; contributing to the general understanding of estuaries through publication of peer-reviewed papers; training undergraduate and graduate students in estuarine studies and fish sampling; and providing a way for managers, biologists, and anyone else interested in the marsh to experience it firsthand.

Pic 3 suisunThirty-nine years of annual otter trawl catches of the Suisun Marsh Fish Study, with key events noted. Note that catches of native and non-native fishes generally follow similar trends.

Our study has documented many patterns in the ecology of the fishes in both space and time. Moyle et al. (1986) evaluated the first five years of data and found three groups of fish species: one that was generally most abundant early in the calendar year (including small staghorn sculpin and starry flounder); another that was common in cool months (including threadfin shad, Delta smelt, and longfin smelt); and a third that was always present in the marsh, comprised of many species but dominated by Sacramento splittail, striped bass, and tule perch.  The species composition of the fish assemblage was relatively constant across years.  Native fishes were more prevalent in small, shallow sloughs, while non-native species were more prominent in large sloughs.

Total fish abundance declined across years because extremely favorable spawning and rearing conditions early in the study period were followed by both a drought and a major flood that resulted in poor recruitment (see figure).

Meng et al. (1994) incorporated eight more years into their analysis, which revealed that the composition of the fish assemblage was less constant over the longer period than the earlier study indicated. In addition, non-native fishes had become more common in small, shallow sloughs. This study also found a general decline in total fish abundance through time. The decreasing fish numbers appeared to be related to (1) drought and high salinities harming both native and non-native fishes, (2) effects of new invasions (e.g., overbite clam), and (3) increases in water diversions.

Eight years later, Matern et al. (2002) found results similar to Meng et al. (1994): fish diversity was highest in small sloughs, and fish abundances had fallen further.  However, since then, fish catches have often been higher, particularly in wet years. Notably, some fishes that have become scarce in the estuary’s main rivers and bays since the early 2000s have either increased (e.g., Sacramento splittail) or remained abundant (e.g., small striped bass) in Suisun Marsh.

While analyzing data collected in 2018, we noted the following trends in some key species:

Delta smelt.  For the third consecutive year, we caught no Delta smelt, providing further evidence that this species is approaching extinction in the wild.

Longfin smelt.  Numbers of this smelt remained very low, but a few were caught almost every month.

Threadfin shad.  This non-native shad is one of the most abundant plankton-feeding fish in the marsh with numbers that fluctuate greatly from year to year. Numbers seem to be gradually increasing from its lows in 1989-1995, with a peak in 2017.  Numbers in 2018 were considerably less than in 2017, but still in the top five years.

American shad.  Since 2001, the number of juvenile American shad, a non-native anadromous species, has gradually increased, roughly following abundance trends of threadfin shad, including record numbers caught in 2017.  This suggests that the two shad species are generally being affected by the same factors.

Striped bass juveniles are also non-native plankton feeders and are typically the most abundant fish in our trawl catches. They also had a peak in 2017, with a drop in 2018 to more typical numbers. However, the long-term trend in catch since 1980 is mildly downwards, with lots of erratic rises and falls from year to year.

Sacramento splittail is a native fish that spawns on floodplains upstream of the marsh but spends most of its time in the marsh feeding on invertebrates.  After a severe decline from 1980 to 1994, its numbers have steadily increased, with 2018 being the peak year for abundance.  We suspect that its continued increase through wet and dry years results from restoration actions on the Yolo Bypass and Cosumnes River floodplains coupled with favorable conditions in the marsh.


Sacramento splittail are native fish uncommon outside of Suisun Marsh, except when they leave to migrate upstream to spawn on floodplains. Photo by Teejay O’Rear

White catfish, a non-native, almost disappeared from Suisun Marsh during the 2012-2016 drought, because high salinities and low flows inhibited reproduction. High flows in 2017 did not replenish the population, so catches remained low in 2017 and 2018.

Mississippi silverside is an abundant non-native species that probably invaded the marsh just a few years before our study began. It hugs the edges of sloughs during the day and feeds on small invertebrates and larval fish. Numbers increased steadily to 2006 and then dropped to consistent, moderate levels.

Overall, 2018 was a modest year for native and other important fishes. After achieving very high numbers in the wet year of 2017 (see figure), fish abundances returned to more typical levels in 2018.  Non-native fishes dependent on plankton for part of their life cycle (American shad, threadfin shad, striped bass) declined from 2017 to 2018, but they were still relatively abundant in Suisun Marsh in contrast to the bays and large rivers of the estuary. However, native smelts were virtually absent in both Suisun Marsh and the main bays/rivers. The negligible smelt numbers and lower numbers of some other native fishes after 2017 (threespine stickleback, prickly sculpin) in Suisun Marsh were contrasted by the highest-ever abundance of Sacramento splittail.

In sum, the catches in 2018 highlighted:

  • the importance of flows and related salinities on fish abundance in Suisun Marsh, with higher flows generally yielding more fish, both native and non-native;
  • the disproportionate importance of Suisun Marsh for warm-water planktivorous fishes, especially striped bass juveniles;
  • the importance of the marsh as a nursery area for many species; and
  • the importance of Suisun Marsh as the estuary’s bastion for Sacramento splittail.

We continue to be fascinated by the dynamic nature of Suisun Marsh and the abundance of life it supports.  We also are improving our understanding of how diverse environmental factors, from droughts to operation of water projects, affect the marsh’s fishes. Our 40 years of study are likely to be especially useful in determining – and predicting – the effects of global climate change on the estuary and its fishes.

For more complete information see O’Rear et al. (2019). For an overview of Suisun Marsh, see Moyle et al. 2014.

Teejay O’Rear is a fish ecologist at the Center for Watershed Sciences. Peter B. Moyle is a UC Davis Professor Emeritus of fish biology and an associate director of the Center for Watershed Sciences.

Further reading

California Department of Fish and Wildlife. 2019. Trends in abundance of selected species. Available: (March 2019).

Matern, S. A., P. B. Moyle, and L. C. Pierce. 2002. Native and alien fishes in a California estuarine marsh: twenty-one years of changing assemblages. Transactions of the American Fisheries Society 131: 797-816.

Meng, L., P. B. Moyle, and B. Herbold. 1994. Changes in abundance and distribution of native and alien fishes of Suisun Marsh. Transactions of the American Fisheries Society 123: 498-507.

Moyle, P. B., R. A. Daniels, B. Herbold, and D. M. Baltz. 1986. Patterns in distribution and abundance of a noncoevolved assemblage of estuarine fishes in California. U. S. National Marine Fisheries Service Fishery Bulletin 84(1): 105-117.

Moyle, P. B., A. D. Manfree, and P. L. Fielder. 2014. Suisun Marsh: ecological history and possible futures. Oakland: University of California Press.

O’Rear, T. A., P. B. Moyle, and J. R. Durand. 2019. Suisun Marsh Fish Study: trends in fish and invertebrate populations of Suisun Marsh January 2017 – December 2017. California, California Department of Water Resources.  Available at:

Editorial note: appears to have surpassed 12,000 followers.  Thanks to the blog’s many contributors, readers, forwarders, editors, reviewers, commenters, and discussers who have made the blog useful and/or entertaining over the years.  We always encourage thought-provoking readable pieces that have at least a tinge of scholarly insight for real people involved in California’s diverse and complex water problems.

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Can Water Agencies Work Together Sustainably? – Lessons from Metropolitan Planning

by Jay Lundmpo-map.jpg

It is said that, “In the US, we hate government so much that we have thousands of them.”  This decentralization has advantages, but poses problems for integration.

Integration is easy to say, and hard to do.  Integration is especially hard, and unavoidably imperfect, for organizing common functions across different agencies with different missions and governing authorities.  (Similar problems exist for organizing common functions across programs within a single agency.)

Much of what is called for in California water requires greater devotion of leadership, resources, and organization to multi-agency efforts.  Some identified needs include:

  • A common state water accounting framework to support groundwater management, environmental flows, water rights, water markets, and a range of voluntary agreements (Escriva-Bou et al. 2016; Bruun 2017).
  • Common frameworks to harmonize regulations across agencies to better achieve societal objectives (Gray et al. 2013).
  • Cross-agency science programs to give a common foundation for policy discussions, management, negotiations, and agreements (DSP 2019).
  • Cross-agency structured forums where issues, future conditions, alternatives, and plans can be responsibly developed and explored without the blinders of individual agency inconvenience.

Many despair that such integration is impossible, or fear that multi-agency efforts will diminish single-agency effectiveness.  To the contrary, today’s lack of common frameworks for integration often creates a brutal and insufficient incrementalism that diminishes the power and reputations of all individual agencies, and reduces the overall reputation of government for achieving societal objectives.

This blog post looks at some success with the similar problem of metropolitan planning for transportation, land use, and environmental planning.  The intent is to:

  1. Show that interagency planning and operational integration is possible and can be effective (if unavoidably imperfect) and
  2. Identify some likely preconditions and lessons for sustaining common interagency functions.

Perhaps this will encourage less fearful and more forward-looking discussions on how to better support needed common water management functions that cross agency boundaries and missions and serve society’s overall objectives for water management.

Metropolitan region planning

Metropolitan governance in the US also is notoriously fragmented.  Since the 1960s, metropolitan areas across the US have had Metropolitan Planning Organizations (MPOs) to regionally coordinate local, state, and federal governments and funding for transportation, land use, air quality, and sometimes other functions.   These are imperfect, but seem to have been useful and effective.  Most US metropolitan areas have MPOs (California has 18), including SACOG for the Sacramento region, the San Francisco Bay Area’s Metropolitan Transportation Commission, and the Southern California Association of Governments (including 6 counties and 191 cities).  DOT 2017 is a good general reference on MPOs.

MPOs coordinate local land use and transportation plans with state and federal plans and planning efforts.  Their composition, governance, activities, and funding vary considerably and are established locally, but they all must meet federal planning requirements for local agencies to receive federal transportation and other funds (much of which are returns of federal fuel tax revenues).

MPOs are housed in a host agency or operate as a separate agency.  They support common technical work in-house or by member agencies.  Common modeling of transportation demands and forecasts, congestion, and coordination of investments and plans helps all local MPO members as well as various state and federal transportation, environmental, housing, and social service agencies.  MPOs also serve as a forum to discuss and coordinate work on common issues and functions needed for both local and regional effectiveness.

MPO funding varies considerably but is a mix of federal, local, and state funds, averaging: Federal: 79% (62% federal planning, 10% federal transit planning, urban transportation 6%, congestion & air quality 1%), Local members: 10%, State: 7%, and Other: 4% (including fees for service 1%, grants 1%, and other 3%).  Integration often requires substantial outside funding, along with outside mandates and requirements.

Some lessons

  • It is possible to organize common technical and operational activities across agencies. Some sectors have done this regionally, such as metropolitan transportation planning, which has often broadened to include land use, housing, air quality, and other functions across agencies.  Such integration is rarely pretty, but is important and useful.
  • Agencies need reasons and frameworks to cooperate or integrate. Integration and coordination seem to require: a) a rationale for improving individual agency mission effectiveness, b) a mandate to work together from state or federal leadership, c) an organizational framework to reduce the transaction costs of integration, and d) money and streamlined regulation tied to effective cooperation or integration.
  • Sometimes looking outside of water can give insights for water management. Regional water integration might learn something from our transportation neighbors. Some MPO experiences might be adapted for basin or regional integration of local, state, and federal efforts for water supply, flood, water quality, and ecosystem functions.
  • Effective portfolio approaches will likely need to be developed and sustained in regional forums or agencies. Some examples today of such functionality exist in transportation (MPOs), and more narrowly as regional water quality control boards, regional water supply agencies (MWDSC, SDCWA, SCVWD), and for the Delta (DSC, DPC).  Some development along these lines might be useful for regionally organizing local and state water efforts more generally.

Just because integrating water management is hard, doesn’t mean California cannot do better.

Further Reading

Bruun, B. (2017), “The regional water planning process: a Texas success story,” Texas Water Journal, Volume 8, Number 1.

CALCOG (2019), Regional Governance, web site.

DOT (2017), MPO Staffing and Organizational Structures, US Department of Transportation, Federal Highway Administration, 162 pp.

Goldman, T. and E. Deakin (2000), “Regionalism Through Partnerships? Metropolitan Planning Since ISTEA,” Berkeley Planning Journal, Volume 14, Issue 1.

Hanak, E., J. Lund, A. Dinar, B. Gray, R. Howitt, J. Mount, P. Moyle, and B. Thompson (2011), Managing California’s Water:  From Conflict to Reconciliation, Public Policy Institute of California, San Francisco, CA.

ILG (2019), Metropolitan Planning Organizations: SB 375 Updates, Institute for Local Government web site.

Lund, J. (2019), Sustaining integrated portfolios for managing water in California, CaliforniaWaterBlog, 23 June.

Wikipedia (2019), Metropolitan Planning Organizations,

Jay Lund is the Director of the Center for Watershed Sciences at the University of California – Davis.  As an undergraduate regional planning and political science student, he was an intern with the Wilmington Metropolitan Area Planning Council (WILMAPCO), an MPO which we affectionately called “Wilmington Map Company.”


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What Water is Covered by the Clean Water Act?


Sunset over the Sacramento River. This navigable water body is a jurisdictional water under the Clean Water Act.

by Karrigan Bork

It is important if a stream, river, wetland, or even a dry ditch is protected by the Clean Water Act (CWA). The CWA is a federal law “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.”[1] But the Act doesn’t cover all waters. Waters covered by the Act, called “jurisdictional waters,” are determined by the language of the Act and by court decisions and administrative rulemakings interpreting that language. Ongoing rulemaking efforts by the Trump administration, coupled with several recent court decisions, make defining jurisdictional waters very difficult.

CWA jurisdiction matters for two main reasons. First, the Act’s significant protections only apply to waters that are covered by the Act. The CWA bars the unpermitted discharge pollutants by any person to jurisdictional waters, but provides no protection to other waters.

Second, getting a permit to discharge a pollutant to jurisdictional waters requires compliance with a host of federal environmental laws. Projects in jurisdictional waters must work through both an environmental analysis under the National Environmental Policy Act (NEPA) and an analysis of the project’s impacts on threatened or endangered species under Section 7 of the federal Endangered Species Act (ESA), in addition to the requisite analysis under the Clean Water Act. And federal projects in jurisdictional waters must get permission from the state water board before they can proceed; projects not in jurisdictional waters require no such permission. Projects in non-jurisdictional waters require no NEPA analysis and do not require consultation under the ESA. Determining whether a given water is jurisdictional is a big deal.

Picture 2 KBork

Is this wetland a jurisdictional water? Depends how close it is to a traditional navigable water, what state it is in, and which Supreme Court Justice you ask.

CWA Jurisdiction Nationwide

CWA determinations seem like an easy question. The language of the CWA covers “navigable waters.”[2] But in legal settings, “navigable waters” means many different things, depending on the context, such as for state title to riverbeds, for commerce, or for public trust purposes.[3] In the CWA context, Congress explicitly defined “navigable waters” to means “waters of the United States.”[4] Not much help there. Congress also emphasized the breadth of the language; the legislative history notes that “[t]he conferees fully intend that the term ‘navigable waters’ be given the broadest possible constitutional interpretation.”[5]

The two agencies responsible for implementing the CWA, the Environmental Protection Agency (EPA) and the Army Corps of Engineers (COE), have interpreted this language in numerous rulemakings since passage of the Act. These rules have the force of federal law. In turn, these rulemakings have been challenged in court, and several Supreme Court cases have further fleshed out the meaning of “waters of the United States”.[6] There’s a long legal history, summarized here.

First, in the 1985 Supreme Court decision United States v. Riverside Bayview Homes, a unanimous Court determined that wetlands adjacent to navigable waters were jurisdictional.[7] Second, the 2001 Supreme Court decision Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers (SWANCC) determined that isolated non-navigable intrastate ponds were not jurisdictional.[8] And third, in the 2006 decision Rapanos v. United States, the Court again tried to iron out the definition.[9]

The Rapanos decision is a mess—few justices could agree on anything, and the decision ultimately included five separate opinions. There is no majority opinion. Four justices wrote one opinion, four justices another, one justice wrote his own opinion, and two others wrote additional concurrences or dissents. That means there’s no clear controlling decision, and anyone trying to apply the decision has a very hard time knowing what to do.

One opinion, written by Justice Scalia on behalf of Chief Justice Roberts, Justice Thomas and Justice Alito, determined that jurisdictional waters must be either traditional navigable waters, “relatively permanent bod[ies] of water connected to traditional interstate navigable waters”[10] (not ephemeral or intermittent flows), or wetlands adjacent to either of those water bodies. The plurality specifically rejected wetlands adjacent to waters that flowed only intermittently. But with only four justices, this opinion is not binding on anyone; that takes a five-justice majority.

A second opinion, from Justices Stevens, Souter, Ginsburg and Breyer, would have deferred to the EPA/COE definition of jurisdictional waters and rejected the idea that intermittent or ephemeral waters could not be jurisdictional.[11] They explicitly would cover geographic features like ephemeral streams, dry arroyos, and slot canyons, not covered under Scalia’s view. But again, this decision also wasn’t controlling.

In this strange situation, Justice Kennedy, who wrote his own opinion with no other justices, ended up holding the most sway. It’s difficult to explain why, but it boils down to counting votes on the Court. The four dissenting justices said they would agree with Justice Kennedy, although they thought he didn’t go far enough. That meant that a future regulation, based on Kennedy’s opinion, would likely be upheld by the Court on a 5-4 vote (Justices Kennedy, Stevens, Souter, Ginsburg and Breyer). No other justice offered an opinion that would get a similar 5-justice majority. This logic is less sound now, given the significant changes on the Court (four new Justices have joined the Court since Rapanos), but it still seems to be the controlling approach. It is unclear what the current Court would do in a similar situation.

Kennedy’s opinion decided that jurisdictional waters were those that have a “significant nexus” to traditional navigable waters, such that “the wetlands, either alone or in combination with similarly situated lands in the region, significantly affect the chemical, physical, and biological integrity of other covered waters more readily understood as ‘navigable.’”[12] Justice Kennedy’s opinion includes as jurisdictional waters any waters, even ephemeral or intermittent flows, if they are “likely to play an important role in the integrity of an aquatic system comprising navigable waters as traditionally understood.”[13] Determining whether any particular water was jurisdictional, under Kennedy’s opinion, requires a fact-based inquiry as to the relationship of that water to navigable waters nearby.

Based on the Kennedy opinion, EPA/COE wrote a new regulation defining jurisdictional waters, which went into effect on August 28, 2015.[14] If this rule, “The Clean Water Rule: Definition of ‘Waters of the United States,’” were in effect, we wouldn’t need to worry about all the Supreme Court decisions leading in to it, and we could just focus on the definition in the 2015 Rule. But, based on litigation to stop the 2015 Rule, the Federal 6th Circuit Court kept the rule from going into effect in an Oct. 9, 2015 decision. Just over a year later, President Trump took office and targeted the 2015 Rule for reform. Since then, it has been a regulatory and judicial whirlwind, with many new rules and lawsuits.

On Feb. 28, 2017, President Trump issued an executive order requiring review of the 2015 Rule. EPA/COE immediately proposed a new rule that would rescind/revise the 2015 Rule. Almost a year later, on Jan. 22, 2018, the Supreme Court reversed the 6th Circuit’s decision that kept the 2015 Rule from becoming law. With that decision, the 2015 Rule became the law of the land. But just nine days later, a new rule from the EPA/COE changed the effective date of 2015 Rule to 2020, so the 2015 Rule was no longer in effect. Then, on Aug. 16, 2018 , a South Carolina District Court invalidated the rule changing the effective date, but only for 26 states. That brought the 2015 Rule back into effect in those 26 states, but not other 24 states (two other lawsuits block application of the rule in those states; based on other decisions, the rule appears to be in effect in roughly 22 states, but it is not entirely clear).

In Dec. 2018, EPA/COE proposed a new rule defining WOTUS, based largely on Justice Scalia’s opinion in Rapanos. The proposed rule excludes ephemeral streams and related features and only includes adjacent wetlands if they “are physically and meaningfully connected to other jurisdictional waters.” The comment period for that rule ended on April 15, 2019, with the definition of jurisdictional waters currently in a holding pattern, waiting for the administration to publish the final new rule. Based on Obama Administration estimates, the proposed rule would reduce coverage of wetlands by 51% and coverage of streams by 18% nation-wide.

pic 3 Karrigan

What about this dry riverbed? Under Rapanos, Retired Supreme Court Justices Kennedy, Stevens, and Souter and current Justices Ginsburg and Breyer would say it’s a jurisdictional water, but Former Justice Scalia, current Justices Thomas and Alito, and Chief Justice Roberts would say no. Given that it takes five justices for a majority, and with the new Justices Kavanaugh, Kagan, Sotomayor, and Gorsuch joining the court since Rapanos, no one knows for sure.

Back Home in California

Where does this all leave California? The 2015 Rule is in effect in California in the near term, so projects starting now follow that rule for determining whether they affect jurisdictional waters.

But the replacement rule is expected in the next year from the Trump Administration, and that rule will likely displace the 2015 Rule everywhere, including in California. Estimates suggest that the new rule will reduce jurisdictional waters in southern California by 60-80% and jurisdictional streams statewide by two-thirds, generally driven by the new rule’s restriction of protection to permanent waters. The new rule, once in effect, will dramatically shrink the federal role in protecting California water quality, reduce the waters where compliance with NEPA and ESA consultation is required, and shrink the state’s ability to condition federal projects.

The new rule will face legal challenges, and those cases will likely take several years to resolve. At this point, it is unclear what rules, if any, will determine federal jurisdiction in the interim. Perhaps the 2015 Rule? If there is no active administrative rule, EPA/COE will apply the law from Rapanos, although which opinion they choose remains to be seen. Given their administrative discretion, it seems likely they will lean toward the Scalia opinion, but federal CWA jurisdiction in California will remain murky for the foreseeable future.

California is also acting on its own to address water quality and protect wetlands, filling the gap left by the federal government, writing new regulations under the California Porter–Cologne Water Quality Control Act (Water Code, Section 13000, et seq.). The Porter–Cologne Act defines “waters of the state” as “any surface or groundwater … within the boundaries of the state.” It explicitly includes all CWA jurisdictional waters but goes far beyond those waters. Notably, states inherently have more power than the federal government to regulate their waters, with fewer Constitutional limitations.

The California’s State Water Resources Control Board (SWRCB) adopted the new regulations April 2, 2019, and the rules will take effect nine months after their approval by the State Office of Administrative Law, a step that should happen soon. The state regulations protect any water ever covered by the CWA, some artificial wetlands, and seasonal wetlands in arid regions that lack wetland vegetation, and groundwater. The regulations also establish a state permitting process for those seeking to discharge pollutants, including dredge or fill materials, into these state-regulated waters.

The new regulations will maintain many protections for California waters, regardless of what happens at the federal level. But this isn’t really a happy ending—the loss of a federal hook for these waters will eliminate the federal role in permitting and may decrease their level of protection. And California may lose its ability to regulate federal projects that affect these waters. Beyond California, the level of protection afforded by states for their own water resources varies widely, and in many states the loss of federal jurisdiction will leave waters unprotected.

This is an important issue that bears watching.

Karrigan Bork is an Acting Professor of Law at the University of California, Davis.

End Notes

[1] 33 U.S.C. §1251 (a).

[2] 33 U.S.C. §1362 (12).

[3] Robin Craig, Navigability and its Consequences: State Title, Mineral Rights, and the Public Trust Doctrine, 61st Annual Rocky Mountain Mineral Law Institute (2015).

[4] Federal Water Pollution Control Act Amendments of 1972, tit. V. §502, Pub. L. No. 92-500, 86 Stat. 886 (codified at 33 U.S.C. §1362(7)(2000)).

[5] S. Rept. 92-1236, at 144 (1972).

[6] Among acronym happy lawyers, this is SCOTUS on WOTUS.

[7] 474 U.S. 121 (1985).

[8] 531 U.S. 159 (2001).

[9] 547 U.S. 715 (2006).

[10] 547 U.S. 715, 742 (2006).

[11] Id. at 802.

[12] Id. 733-735.

[13] Id. at 781.

[14] Clean Water Rule: Definition of “Waters of the United States”, 80 Fed. Reg. 37,054, 37,098 (June 29, 2015) (to be codified at 33 C.F.R pt. 328, and 40 C.F.R. pgs. 110, 112, 116, et al.) noting that this approach “balances the exclusion with the need to ensure that covered tributaries, and the significant functions they provide, are preserved.” Id.

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Groundwater Law – Physical – “the water budget myth”

by Jay Lundgroundwater-streamflow

This week’s short post is on groundwater law – from the viewpoint of physics.  Water policy, management, and human law often misunderstand how groundwater and surface water work physically.

Bredehoeft, et al. (1982) distill a longstanding lament of many groundwater experts, “Perhaps the most common misconception in groundwater hydrology is that a water budget of an area determines the magnitude of possible groundwater development.  Several well-known hydrologists have addressed this misconception and attempted to dispel it.  Somehow, though, it persists and continues to color decisions by the water-management community.”

Long ago, the venerable Theis (1940) summarized:  “Under natural conditions … previous to development by wells, aquifers are in a state of approximate dynamic equilibrium.  Discharge by wells is thus a new discharge superimposed upon a previously stable system, and it must be balanced by an increase in the recharge of the aquifer, or by a decrease in the old natural discharge, or by loss of storage in the aquifer, or by a combination of these.”

As Bredehoeft, et al (1982) conclude:

“1. Magnitude of [groundwater] development depends on hydrologic effects that you want to tolerate, ultimately or at any given time (which could be dictated by economics or other factors).  To calculate hydrologic effects, you need to know the hydraulic properties and boundaries of the aquifer. Natural recharge and discharge at no time enter these calculations. Hence, a water budget is of little use in determining magnitude of [sustainable groundwater] development.

2. The magnitude of sustained groundwater pumpage generally depends on how much of the natural discharge can be captured.

3. Steady state is reached only when pumping is balanced by capture, in most cases the change in recharge is small or zero, and balance must be achieved by a change in discharge. Before any natural discharge can be captured, some water must be removed from storage by pumping. In many circumstances the dynamics of the groundwater system are such that long periods of time are necessary before any kind of an equilibrium condition can develop.  In some circumstances the system response is so slow that mining will continue well beyond any reasonable planning period.

These concepts must be kept in mind to manage groundwater resources adequately. Unfortunately, many of our present legal institutions do not adequately account for them.”

Water budgets are important in managing water, but better water budgets include both surface water and groundwater, which interact naturally and through management.  Most groundwater pumping is ultimately from surface water, taken at some time or place.  Water budgets consisting only of groundwater neglect the laws of physics that govern the sustainability of water management.

In California, local, regional, and state managers and regulators of Sustainable Groundwater Management programs and plans will need to integrate surface water with groundwater.  It’s the physical law, and it is always, eventually enforced.

Further reading

Bredehoeft, J.D., S.S. Papadopulos and H.H. Cooper. 1982. Groundwater: the Water Budget Myth. In Scientific Basis of Water-Resource Management, Studies in Geophysics, Washington, DC: National Academy Press, pp. 51-57.

The Nature Conservancy, RMC Consultants, Inc. (2016), Groundwater and Stream Interaction in California’s Central Valley: Insights for Sustainable Groundwater Management, The Nature Conservancy, Sacramento, CA, 149 pp.

Maven’s Notebook, CA WATER LAW SYMPOSIUM: Questions of common supply: SGMA requirements for interconnected surface water and groundwater, panel discussion summary, June 19, 2019.


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$24.6 Billion National Flood Insurance Program Debt Explained in One Chart

by Kathleen Schaefer

As we are enter another hurricane season, the National Flood Insurance Program (NFIP) is on its 12th short-term extension since September 30, 2017.  And after having $16 billion in debt forgiven, it remains $24.6 billion in debt (Horn 2019). Many people are asking, how did we get here? While “its complicated,” much can be explained by this graph from Oldenborgh et al. (2017), p.6.

Figure for flood frequency

Figure Caption: Fit of the annual maximum three-day average from 85 precipitation gages on the US Gulf Coast. Dashed red line is Generalized Extreme Value (GEV) estimates representing 2017. Solid blue line is GEV estimates scaled down to 1900 based on correlated global temperature changes. The horizontal dotted  green line shows the intensity of the observed event at Baytown, TX, far above any previous observation. Source: van Olderborgh et. al

How this graph explains the $24.6 billion debt, begins with the knowledge that the NFIP is essentially an In-Out Flood Game. FEMA is the referee. They oversee the Flood Insurance Rate Maps (FIRMs) that show the Special Flood Hazard Area (SFHA) or 100-year flood. The FIRMS show who is “in” the floodplain and must pay and who is “out” and freer of building and insurance requirements. Almost every community in America participates in this Flood Game.  Communities that opt out they risk losing access to post-disaster aid. Many cities like Roseville and Sacramento respect the power of floods and embrace the Flood Game—actively participating in activities like the Community Rating System (CRS), saving their citizens hundreds of dollars each year. Other communities focus on short-term growth and commercial development built on ignoring or denying flood risks.  Not wanting to restrict development or force their residents to purchase flood insurance, they view any action that increases the designated floodplain as a “loss”, regardless of how prudent the decision may be in the long term.

Hydrology estimates are critical in this Flood Game. The in-out boundaries can only be adopted by the community after designated experts agree on the 100-year discharge value. Clear, well-defined, stationary, in-out boundaries for the 100-year floodplain have a key role in keeping the players in the game. But hydrology involves uncertainties and is not well charaterized by a single number. So, once everyone has agreed on a boundary, there is great reluctance to change it—even with indisputable climate change.

With that housekeeping out of the way, on to explain the chart.

The chart’s Dutch researchers observed that extreme precipitation along the Texas Gulf Coast has increased 12% to 22% since observations began in 1880. To examine global warming’s contribution to the increase, they compared an ensemble of recorded precipitation gage data from the Gulf Coast to the output from global climate models, finding that the downscaled climate model data fit moderately well. The dotted horizontal  line at 350 mm/day shows how extraordinary Hurricane Harvey was. It dropped more than 60 inches of rain and caused more an estimated $125 billion in damages (Blake and Zelinsky 2018). Harvey was an off-the-chart event. Rare extremes are possible.

The solid blue line is the annual maximum three-day average perception from 85 Gulf Coast precipitation gages scaled down to represent the rainfall distribution that would have been observed in 1900. The dashed red lines are the upper and lower estimates of the annual maximum three-day average perception estimated for 2017 conditions. Van Oldenborgh et al. concluded that global warming has increased the intensity of rainfall in the region by 15% over the last half-century. They suggest that these increases in extreme precipitation should be considered when rebuilding.

This graph also shows that precipitation at recurrence intervals greater than 100-year are possible.  Larger return periods also have greater uncertainty. So precipitation estimates foundational to FEMA Flood Insurance Rate Maps are less certain than current in-out maps would lead one to believe.

Communities who play the Flood Game with reluctance do not want complications from considering additional discharges or uncertainties than the single 100-discharge previously agreed to. However, armed with this graph, the Harris County Flood Control Agency and the City of Houston could have used this moment to justify a higher design discharge value as the hydrology number. But they did not (Harris County Flood Control Agency 2016, 3).

Although NFIP ratepayers and the federal government must ultimately pay for these decisions, and FEMA encourages communities to submit updated hydrology estimates for approval and adoption (44 CFR 66.1), changing the hydrology opens the possibility of redrawing flood rules, maps, and regulatory susceptibility—a messy complicated affair few wish to tackle.

If Houston would have adopted a higher 100-year discharge number, they would have had to admit that FEMA maps are no longer current and that the in-out boundaries need to change. This would have forced more Houstonians to elevate their homes, whether they could afford to or not. It would force hundreds more to buy flood insurance, whether they could afford it or not. Further, as the adoption of FEMA maps is a long process, it would add uncertainty to rebuilding at a time when people want only to get on with rebuilding. Not wanting to be criticized for not taking action, the Houston City Council did increase freeboard requirements for the unfortunates designated as “in” (the SFHA). But, as much as 50% of the homes at high or moderate flood risk are in the perceived “flood free” zone, and by not adopting new hydrology the in-out boundary will remain the same and many will unknowingly rebuild unwisely (CoreLogic).

As a recent Public Media article highlights, once rebuilding is underway, it is hard to change course. Thus, the process repeats (Conrad 1998). Ultimately, Californians will be forced to continue to subsidize the poor development decisions of Houston and other areas for fear that if we do not, Houstonians will not come to our aid when our levees fail. As we have no business telling Houston how to develop, perhaps it is time to remove ourselves from this Faustian bargain, and develop our own modern comprehensive flood risk and insurance program—one that goes beyond the In-Out Flood Game and considers a range of flood events and their uncertainties.

Further reading

Blake, Eric S., and David A. Zelinsky. 2018. “Hurricane Harvey.” Tropical Cyclone Report AL092017. National Hurricane Center. Retrieved from

Conrad, David R. 1998. Higher Ground: A Report on Voluntary Property Buyouts in the Nation’s Floodplains: A Common Ground Solution Serving People at Risk, Taxpayers and the Environment. National Wildlife Federation. Retrieved from

Harris County Flood Control Agency. 2016. “Hcfcd-Hydrology-Hydraulics-Manual_03-2016.pdf.” Retrieved from

Horn, Diane. 2019. “The National Flood Insurance Program: History and Overview.” Retrieved from

Oldenborgh, Geert Jan van, Karin van der Wiel, Antonia Sebastian, Roop Singh, Julie Arrighi, Friederike Otto, Karsten Haustein, Sihan Li, Gabriel Vecchi, and Heidi Cullen. 2017. “Attribution of Extreme Rainfall from Hurricane Harvey, August 2017.” Environmental Research Letters 12 (12): 124009.

Kathleen Schaefer is a PhD student in Civil and Environmental Engineering at the University of California, Davis.  She has a long acquaintance with flood insurance.

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Ties Between the Delta and Groundwater Sustainability in California

by Mustafa Dogan, Ian Buck-Macleod, Josue Medellin-Azuara, and Jay Lund

Groundwater overdraft is a major problem globally and has been a persistent and growing problem in California for decades. This overdraft is predominantly driven by the economic value of water for agricultural production and cities. Spurred by the recent drought, California passed legislation requiring the elimination of groundwater overdraft by 2040. To explore potential water supply effects of ending long-term groundwater overdraft in California’s Central Valley, we compared several water policies with historical and warmer–drier climates, employing a statewide hydroeconomic optimization model, CALVIN, in our new paper. Hydro-economic optimization models like CALVIN allocate water to agricultural and urban users considering hydrologic conditions, infrastructure, and environmental restrictions among other factors, such that systemwide water scarcity and operation costs are minimized.

Groundwater overdraft is a common response to surface water scarcity when the economic value of water use in agriculture and cities exceeds pumping costs. In California, supply and demand disparity combines with a great seasonal and geographical imbalance of water supplies and demands. Water is much more available during winter in northern California, but water demands are mostly in central and southern California during spring and summer.

The Sacramento-San Joaquin Delta (Delta) is the major hub in California’s water system (Figure 1), with environmental and water allocation policies also affecting operation, planning, and management decisions. Changes in regulations and climatic conditions and increasing water demands make Delta water management complex.

Figure 1.png

Figure 1. California’s groundwater basins, aggregated wildlife refuges, and minimum in-stream flow requirements represented in CALVIN, and the Delta water balance (Dogan et al., 2019)

Management Policies

Policy cases examined here put different restrictions on Delta water operations and eliminate groundwater overdraft under 82-year (1921–2003) historical and warmer–drier climates with 2050 agricultural and urban water demands (Table 1). Policy 1 allows historical overdraft rates in CALVIN’s 82-year modeling horizon. A no-overdraft policy is applied to the Central Valley groundwater aquifer in Policies 2–5, requiring that groundwater storage at the end of each 82-year run cannot be less than groundwater storage at each run’s beginning. Policies 3–5 add different Delta export constraints to this no-overdraft policy. Policy 3 maintains historical Delta outflows, by month, in addition to the no-overdraft policy, so reductions in Delta outflows cannot substitute for lost historical supplies from groundwater overdraft. Policy 4 further restricts Delta export operations by constraining water exports to historical quantities, in addition to maintaining a no-overdraft policy. This prevents the optimization model from curtailing water use north of the Delta to supply water south of the Delta to accommodate supplies lost there from ending groundwater overdraft. Policy 5 reduces Delta exports by 95%, largely eliminating them, in addition to maintaining a no-overdraft policy.

Table 1. Policy cases evaluated under historical and perturbed (warmer–drier) climates (modified from Dogan et al., 2019)

Policy Description Importance
Policy 1 Operations with historical overdraft Base case operations
Policy 2 No overdraft Operations without overdraft and with no new Delta restrictions
Policy 3 No overdraft and no reduction in Delta outflow Forces water use reallocation across basins without reducing Delta outflow
Policy 4 No overdraft and no additional Delta exports Operations and use changes occur only within basins, cannot adjust statewide
Policy 5 No overdraft and minimal Delta exports Largely eliminates Delta export water supplies


All analyses have weaknesses and limitations, but the model’s results support several consistent and insightful conclusions, many of which merit further analysis and discussion.

  • California’s two largest water problems, groundwater sustainability and the Sacramento-San Joaquin Delta, are closely tied.
  • With “no overdraft” policy (Policy 2), the 82-year period has two large recovery durations, lasting 62 and 12 years, demonstrating the importance of long-term groundwater planning and the difficulty of assessing groundwater sustainability.
  • If Delta outflow cannot be reduced for environmental and operational reasons (Policy 3), opportunities for Sacramento Valley users to sell some water to south-of-Delta users would be economically worthwhile under historical climatic conditions.
  • If permitted environmentally, diversions from surplus Delta outflow (Policy 3) can reduce (but not eliminate) water scarcities.
  • If Delta exports cannot be increased for environmental and management reasons (Policy 4), regional water trades help reduce water scarcities.
  • Surface water availability and the reliability of Delta exports are significantly reduced with a warmer-drier climate.
  • A warmer-drier climate combined with ending groundwater overdraft and some water management policies would further exacerbate water scarcities and increase environmental and economic costs.
  • Delta water supplies and operations become more important with the end of overdraft and climate change.
  • Economically useful adaptations include more diversions from surplus Delta outflow, increased water transfers involving Delta, water markets and trades, conjunctive use of groundwater and surface water, and recycled wastewater. These would come at a cost and often with additional controversy.

Further Readings

Dogan, M.S., Buck, I., Medellin-Azuara, J., and Lund, J.R. (2019), “Statewide Effects of Ending Long-term Groundwater Overdraft in California,” Journal of Water Resources Planning and Management, 145(9).

Lund, J.R. (2016), “California’s agricultural and urban water supply reliability and the Sacramento-San Joaquin Delta,” San Francisco Estuary Watershed Sci. 14(3).

Dogan, M. S., J. D. Herman, and M. A. Fefer. 2017. “CALVIN source code.” Accessed July 21, 2018.

Buck, I. (2016), “Managing to end groundwater in California’s Central Valley with climate change.” M.S. thesis. Dept. of Civil and Env. Engineering, University of California, Davis.

Dogan, M. S. (2015), “Integrated water operations in California: Hydropower, overdraft, and climate change.” M.S. thesis. Dept. of Civil and Env. Engineering, University of California, Davis.

Mustafa Dogan recently completed his PhD in Civil and Environmental Engineering at the University of California, Davis and is now an Assistant Professor of Civil Engineering at Aksaray University in Turkey. Ian Buck-Macleod is an engineer with Stantec. Josue Medellin-Azuara is an acting Associate Professor of Environmental Engineering at the University of California, Merced.  Jay Lund is a Professor of Civil and Environmental Engineering at the University of California, Davis.

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Challenges and opportunities for integrating small and rural drinking water stakeholders in SGMA implementation

By Kristin Dobbin, Jessica Mendoza and Michael Kuo

The Sustainable Groundwater Management Act (SGMA) is an historic opportunity to achieve long-term sustainable groundwater management and protect drinking water supplies for hundreds of small and rural low-income communities, especially in the San Joaquin Valley. Past research indicates that few of these communities are represented in the Groundwater Sustainability Agencies (GSAs) formed to implement the new law. This raises questions about the extent such communities are involved in groundwater reform and potential concerns about how small and rural drinking-water interests are being incorporated into Groundwater Sustainability Plans (GSPs).

Our new report summarizes results of interviews with more than thirty small (< 10,000 people), low-income community representatives in the San Joaquin Valley providing an important window into community perspectives on, and experiences with, SGMA implementation. How and why are communities involved with SGMA or not? What challenges and opportunities exist for increasing community involvement with SGMA implementation?

The findings suggest communities are highly interested in SGMA and desire to be involved in its implementation, which many deemed indispensable for the future of their communities. Small and rural communities are participating in a variety of ways, including serving on committees, attending meetings and workshop and monitoring meeting minutes and agendas. While interviewees’ experiences in these different capacities are exceedingly diverse, six common challenges and concerns about SGMA implementation arose:

  1. Resource constraints to participation: Lack of staff, small budgets, in-house experts and an inability to pay for outside services/support limited communities’ formal participation in GSA governance and attendance and involvement in SGMA meetings.
  2. Accessibility: Additional factors limiting the accessibility of the SGMA process included day-time meetings, language barriers, the proliferation of board and committee meetings, and irregular and unclear meeting schedules and notices.
  3. Transparency: A lack of transparency in GSA decision-making as well as limited access to the data and information being used to develop Groundwater Sustainability Plans (GSPs) were common concerns for interviewees impacting their desire to participate and trust in the process.
  4. Lack of formal representation: The relegation of communities to advisory, rather than decision-making, roles in the SGMA process was also a common concern.
  5. Limited opportunities to provide meaningful input and feedback: Whether participating as a decision-maker, committee member or as a member of the public attending meetings, many were frustrated at the lack of opportunities to provide meaningful input into decisions or on draft documents due to short turnaround times, not being provided necessary background or materials, and limited opportunities for public comment and open discussion.
  6. Lack of addressing drinking water interests and priorities: Overwhelmingly, interviewees reported that drinking water interests, especially water quality and domestic wells, were not part of their local SGMA conversations, leading many to be skeptical that SGMA would have drinking-water benefits.

The good news is that best practices and recommendations from all of the interviewees highlight ample opportunities to address these issues and increase the integration of drinking-water stakeholders and interests into sustainable groundwater management. Targeted efforts to reduce barriers to participation, improve communication and transparency, and promote diverse representation could go a long way to ensuring the “consideration” and “active involvement” of this important, historically marginalized, stakeholder group. For example, communities can educate their GSA about drinking-water priorities and the variety of regulations and requirements public water systems must comply with and coordinate with other small and rural communities to elevate and advocate for drinking-water needs. GSAs should incorporate available public data into Groundwater Sustainability Plans (GSPs) while developing plans to fill data gaps, provide ample time for feedback on staggered and sequential GSP sections and streamline and increase interaction with stakeholders in meetings. State agencies should consider requiring or incentivizing collaborative community projects be included in GSPs, and community representation in GSP development and implementation as well as provide funding to support meaningful community involvement in all phases of SGMA implementation. The extent to which state, regional and local interests can work together to find and implement inclusive solutions will determine how well SGMA accomplishes its stated goal to “protect communities, farms, and the environment against prolonged dry periods and climate change, preserving water supplies for existing and potential beneficial use” (SGMA, uncodified findings).

To read more and see the full list of recommendations and best practices, read the full report here. A Spanish-language version of the report will be available soon.

Kristin Dobbin is a PhD student in Ecology at UC Davis studying regional water management and drinking water disparities in California. Jessica Mendoza and Michael Kuo are undergraduate research assistants in the UC Davis Center for Environmental Policy and Behavior.

Further Readings

Moran, T. & Belin, A. (2019). A Guide to Water Quality Requirements Under the Sustainable Groundwater Management Act.

Dobbin, K. (2018). Small Disadvantaged Community Participation in Groundwater Sustainability Agencies (English / Spanish).

Feinstein L, R. Phurisamban, A. Ford, C. Tyler and A. Crawford. (2017). Drought and Equity in California

Kiparsky, M., D. Owen, N. Nylen, J. Christian-Smith, B. Cosens, H. Doremus, A. Fisher, A. Milman. (2016). Designing Effective Groundwater Sustainability Agencies: Criteria for evaluation of local governance options.

Dobbin, K., J. Clary, L. Firestone and J. Christian-Smith. (2015). Collaborating for Success: Stakeholder engagement for Sustainable Groundwater Management Act implementation.


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