Indicators of a drought ending in northern California


Sacramento Weir flowing into Yolo Bypass, January 2017, for first time since December 2005, photo: Jay Lund

Jay Lund

Droughts are common in California, a large, generally dry, and hydrologically complex place.  So it is hard to rely on a single index of the end or beginning of a drought.  A single storm is rarely enough to end a drought in California, especially a long drought like the one that seems to be mostly ending now.  Regular hydrologic statistics can be used as indicators of drought, but these do not do justice to how droughts actually end (or begin).

Here are some less formal indicators that the current drought is ending, although in some ways this drought and its impacts will endure for decades to come.

  • Guerneville on the Russian River has flooded. This is usually about the first town to flood in California. Guerneville floods so often that I wonder how it is still there or has not become just a summer camp!
  • Van Sickle Island in the Delta floods. Usually this is the first Delta island to flood.  It has some of the Delta’s lowest and weakest levees, but has mostly ducks for residents.
  • Most reservoirs are full, or at least filled to levels where they are kept partially empty for possible floods.
  • Weirs and bypasses are actively draining the Sacramento Valley. The mighty Fremont Weir has taken control of the Sacramento River, flowing at almost 200,000 cfs.  The Sacramento Weir, completed in 1916, is open for the first time since December 2005.  Awesome!
  • Skiing exists, and seems relatively good. Count the skis racks on cars heading East on Friday afternoons, or heading West at the end of the weekend.  Count the conversations about ski lift lines and ticket price strategies at work on weekdays.
  • My roof leaks and the kids scoff at raking wet leaves. We all have our own personal drought indicators.
  • I feel a need to remind people how dangerous flowing water and floods are.  Don’t wade or drive into moving water, even if it is shallow.  Be careful.

California must now deal with the aftermath of the drought and preparing for the next one, even as some parts of California still suffer from the drought and some areas worry about flooding.  Hopefully southern California, especially poor Lake Cachuma, benefits from storms in the weeks to come.  We live in a complex place.  But it works better if we work at it.

So, back to my roof and putting my kids to work.  Another storm is coming later this week.


Fremont Weir, several feet under water, taking water from Feather and Sacramento Rivers into Yolo Bypass, January 2017. Flow about 180,000 cfs over 2 miles of weir.  Don’t enter if you value your life – very dangerous.

Jay Lund is a professor of civil and environmental engineering and director of the Center for Watershed Sciences at UC Davis.  He came to California just after the 1986 flood and in time for the 1988-92 drought.

Further reading

Sacramento River Flood Control Project Weirs and Flood Relief Structures, by California Department of Water Resources, 2010.

Lund, J.R., “Flood Management in California,” Water, Vol. 4, pp. 157-169; doi:10.3390/w4010157, 2012.

Suddeth, R. and J. Lund “Multi-Purpose Optimization of Reconciliation Ecology for an Engineered Floodplain – Yolo Bypass, California,” San Francisco Estuary and Watershed Science, Volume 14, Issue 1, 2016.


Posted in Uncategorized | 5 Comments

Tails of California’s Drought

plot_esi-4by Jay Lund

Storms are filling reservoirs, building snowpack, and flooding in ways not seen since the most recent California drought began in 2012.  The state’s reservoirs today contain 1.2 million acre-ft more water than the long-term average for this time of year (the first time above average in 6 years).  Two years ago reservoir storage was 8 million acre-ft below average.  Most of the state’s precipitation and snowpack are far above average, boding well for this water year.

In terms of surface water, most of California is no longer in drought.  The accumulated reservoir and soil moisture deficits of the last 5 years have been filled in most of the state.  Only Santa Barbara, supplied by Lake Cachuma (currently 11% of average storage), faces major urban drought.  Most water shortages last year, from inability to move water across the Delta to the southern Central Valley, seem to be overcome this year.   Today, San Luis Reservoir contains 93% of its long-term average storage for this time of year. Unless the remainder of the year is incredibly dry and warm, 2017 will not be a drought for surface water, with perhaps a few local exceptions.

For groundwater, aquifers in northern California should be doing quite well.  They were not terribly depleted during the drought and have wetter conditions to more readily refill them.  For the southern Central Valley and southern California, wetter conditions will reduce pumping and increase recharge.  But these regions have less surface water to recharge aquifers, and the southern Central Valley typically has net aquifer overdraft in all but the wettest years. Some southern Central Valley aquifers might never recover to pre-drought levels.

Droughts often have long tails, especially for extended droughts over such a large state.  Groundwater in the southern Central Valley might rise some, but will remain low, keeping some wells stranded and increasing pumping costs for years and perhaps decades.  Drought damage to California’s forests could require decades to recover, or, if higher temperatures persist, the ecology of many forests might shift to new normal conditions.  Native fish also will likely need years to recover – with impediments from already depleted numbers and highly disrupted and altered ecosystems.

Droughts usually bring water shortages, but not all water shortages are from drought.  Some speak of drought as permanent for California.  But, it is better to think of California being a dry place with permanent water shortages (except in unusual wet years), which is also prone to drier than average years, which are droughts.  California must reconcile itself to being a dry place and some long-term water shortages.  It must also prepare for periods of drier than average conditions with greater shortages and costs, which are droughts.

For policy-makers the distinction is important. If every year is labeled a drought crisis or emergency, then “drought” loses important meaning and urgency needed to motivate and conserve to higher levels in drier conditions.  In addition to managing during drought, we must manage other years for normally dry conditions, which will often include deliveries less than desires and storing water and suppressing some demands in preparation for still-drier drought conditions.

As this drought goes out the door, it will say, in the words of our former Governor, “I’ll be back.”

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

Some further reading

You Can’t Always Get What You Want – A Mick Jagger Theory of Drought Management

Improving mandatory State cutbacks of urban water use for a 5th year of drought

The banality of California’s ‘1,200-year’ drought

Why utilities shy from mandatory water saving during a drought

Is shorting fish of water during drought good for water users?

Posted in Uncategorized | 11 Comments

Out With the Old Drought and In With the New?

By Jay Lund

We are just a few months into this year’s wet season, and progress has been great.  Statewide, California is about 800,000 acre ft below average surface water storage for this time of year.  California’s water year began with surface storage about 3 million acre ft (3 full Folsom Reservoirs) less than historical averages for October 1.  This was already a great improvement from the previous year’s being 8 maf below average in January 2016.

While we are still in early days for this water year (October 2016-September 2017), California precipitation is above average for this time of year, 178% of average in Sacramento Valley, 145% in San Joaquin Valley, and 127% in Tulare Basin.  Southern California is further behind, but has gotten some good storms in recent weeks.  Overall snowpack is 72% of average for this time of year (perhaps reflecting warmer conditions).  If no more precipitation fell in northern California, with more than 3 months left in the wet season, total precipitation would be a bit less than the 2015 water year.

But drought remains in some parts of California.  The Santa Barbara area is at great risk now, with its Lake Cachuma still at 8% of capacity and 11% of average storage for this time of year.  But continued wetness in southern California might resolve this.

Fish and forests throughout the state, and groundwater south of Delta will have lingering effects from previous years of drought if most of California continues to be wet.

If this year continues to be mostly wet, water shortages are still likely for some parts of California.  The drought and growing demands have left some parts of California, particularly the southern Central Valley, in an largely permanent structural drought.  Here, there is more water demand than water available.  This condition developed from growing water demands for increasingly profitable agriculture and for growing cities encountering reduced ability to import water from the Delta due to endangered species and Delta water quality.  This gap will worsen as restrictions ending groundwater overdraft come to bear (to provide more drought security for profitable agriculture) and as environmental flow requirements increase.

Overall, drought conditions continue to lessen in most of California, but it is still early days.  Even with continued wet conditions the drought could worsen in some areas, such as Santa Barbara, even as it disappears from other areas.  And the previous years of drought will have a long tail of impacts in many areas, and innovations from the drought, such as groundwater management, need to be with us for a long time.

Some lessons from this drought?

You Can’t Always Get What You Want – A Mick Jagger Theory of Drought Management

The banality of California’s ‘1,200-year’ drought

Improving mandatory State cutbacks of urban water use for a 5th year of drought

Jay Lund is Director of the Center for Watershed Sciences and a Professor of Civil and Environmental Engineering at the University of California – Davis.

Two notes of celebration for 2016!

First, ends 2016 having surpassed 800,000 views since 2011, with almost 8,500 subscribers.  Thanks to everyone!  We hope our short essays are useful, or at least entertaining.

Second, UC Davis now has a professional master’s degree program in Environmental Policy and Management, geared especially for students with science or engineering backgrounds seeking leadership careers in policy and management.  This program has been too long in coming, but has a bright future at the world’s strongest overall environmental campus.  For more information, see:


Posted in Uncategorized | 4 Comments

Shadow theater and data management for the Delta – a video

By Amber Manfree

Data and data management are persistent concerns for the Delta and California water more generally. Data Wars: A New Hope, a shadow puppet play on the subject, was shown at the 2016 Bay-Delta Science Conference in Sacramento. The challenge of the Conference’s theme, “Science for Solutions: Linking Data and Decisions,” is illustrated by characters such as a lonesome marsh wren and a striped bass with a Boston accent.

The video highlights a fundamental problem facing Delta stakeholders: how to make sound decisions based on science when no one seems to agree on objectives. It lends some comic relief to a seemingly intractable issue. It was also fun to create.

Over a dozen scientists collaborated on this work, including voice-overs by Bruce Herbold and Peter Moyle and puppet design by Micah Bisson and Rosemary Hartman. Musical accompaniment was arranged and recorded by Kyle Phillips. Amber Manfree, an avid shadow puppeteer, directed the project. Video production and technical advice from Megan Nguyen translated the play to video.

Thoughts on Communicating Science

Packaging science to appeal to a broad audience is critical, yet scientists and technical people rarely have training in communication. Those who create scientific content can improve communication in two ways: by honing skills and collaborating with others.

1. Gain Skills. Even scientists can develop and improve artistic skill, but it takes attention and effort. Like ice skating, slick graphics require by many, many attempts. Cultivating a habit of sketching in field notebooks or hand-drawing charts before generating them digitally is one way to get started. Paying attention to and mimicking well-designed graphics aids rapid advances. Once basic graphics have been laid out, they can almost always be improved with feedback from reviewers and touch-ups with graphic design software such as Adobe Photoshop, Illustrator, or GIMP/GNU. Online tutorials are widely available.

2. Collaborate. Expand your network and collaborate with talented visual communicators, secure funding to support them, bring them into your fold, and learn from them. The Bay-Delta Science Conference Art Committee worked to pair artists with scientists to create original works for the conference. This expanded how scientists think about communication, and expanded how artists approached their work.

Amber Manfree is a postdoctoral researcher with the UC Davis Center for Watershed Sciences. When she isn’t sampling fishes, data gazing, or researching, she can be found designing materials that join art and science.

Further Reading

Some examples of art-science collaborations:


Posted in Tools | Tagged , , , , | 1 Comment

California, Flood Risk, and the National Flood Insurance Program

California, 3/98: El Nino storms flood the Russian River. Photo by DAVE GATLEY/FEMA News Photo Mandatory credit (no charge for image use)

California, 3/98: El Nino storms flood the Russian River.
Photo by DAVE GATLEY/FEMA News Photo

by Nicholas Pinter, Rui Hui, and Kathy Schaefer

Across the US and worldwide, flooding is the deadliest and most costly natural disaster.  The US National Flood Insurance Program (NFIP) is an imperfect framework for reducing flood losses, but currently the best we’ve got.  NFIP is scheduled for Congressional reauthorization in 2017, and this debate promises to be lively.  The Natural Hazards Research and Mitigation Group at UC Davis has been analyzing NFIP databases, examining patterns over the history of the program and focusing on flood losses and flood insurance, particularly in California.

Over the history of NFIP, California is one of a few states that has – through dry years and wet – received only a small fraction of payments from NFIP compared to the premiums it has paid in.  Since 1994, NFIP damage payouts in California have totaled just 14% of premiums collected (compared to 560% for the biggest recipient state, Mississippi).  For California, this imbalance exceeds $3 billion (2015 dollars) over 21 years, funds that could have been invested in risk-reduction, floodplain management, and reduced premiums.

California has unparalleled expertise and a culture of progressive solutions for managing its flood risk; the state also has unique needs and intense pressures looking forward.  With the US NFIP facing an uncertain future – >$20 billion in debt, and with a challenging Congressional reauthorization discussion looming in 2017 – we recommend a careful look at California’s place in the NFIP.  In particular, California should now explore a state flood insurance program, with savings invested in long-term risk reduction.  Properly implemented, a state-based insurance program and proactive flood mitigation strategies could synergistically benefit the environment, agriculture, recreation, and water resources.  This approach has major challenges, with implications both for California and nationwide that should be explored.


The National Flood Insurance Program (NFIP) was established in 1968 to curtail development on US floodplains and along our coasts.  Until that time, homes and businesses were being built on flood-prone land almost without restraint.  Flood damages were multiplying out of control, and private insurers had stopped offering flood coverage to homeowners and all but the largest businesses.  As disastrous floods struck through the 1950s and 60s, victims had nowhere to turn but the federal government, and US taxpayers saw spiraling payouts for disaster relief.  NFIP established a grand compromise – if communities would pass ordinances to limit new construction on floodplains and coastlines (and other activities that worsen flood damages), then the federal government would help provide flood insurance in those communities.  Today NFIP underwrites over 5 million policies, providing over $1.25 trillion in coverage, taking in over $3.5 billion/year in premiums. NFIP has limited, but not halted floodplain development. But flood losses have continued to climb, and NFIP is now >$20 billion in debt.

We examined nationwide databases of NFIP flood-damage claims dating back to 1972, annual policies since 1994, and records of properties with multiple payouts (FEMA “severe repetitive loss” properties). These data include property characteristics, insurance claims, and the nature of flood losses. Some attributes were stripped from the databases to maintain policyholder anonymity.  We combined NFIP data with other GIS information, such as income data and social vulnerability to examine affordability and equity of NFIP coverage.

California, Flood Risk, and the NFIP

Despite more than a century of investment in controlling flood threats, including $11 billion in flood management projects over the past decade (DWR, 2013), California still has massive flood-risk exposure.  Statewide, roughly 7 million people and $580 billion in buildings, public infrastructure, and crops are at risk from flooding (DWR, 2013).  Of 81 Major Disaster Declarations in the state since 1954, 45 involved flooding.

The Central Valley is the most flood-prone area of the State, a threat addressed during the past 100+ years by construction of levees, bypass channels, and upstream dams.  In recent decades, developers and local officials have engaged in a tug-of-war with floodplain managers and flood-risk researchers, with local interests promoting new development on California’s floodplains behind levees, some of them strengthened and providing high levels of protection (others less).  However, no levee provides complete protection –  “There are two kinds of levees … [t]hose that have failed and those that will fail” (Martindale and Osman, 2010).  Levee projects accompanied by additional floodplain development often increase total risk and flood liability (California Water Blog, July 17, 2016).

To counterbalance this threat, California has 290,000 NFIP policies in force, covering nearly $82.6 billion of insured assets, and generating $212.8 million in annual premiums (data to 10/31/2016).  Table 1 shows the current distribution of NFIP insurance across California.  These totals include residential, commercial, and some government properties on river floodplains and along coastlines.  NFIP also insures properties outside of mapped flood-hazard zones, roughly one-third of all policies nationwide (Rand Corporation, 2006).  The UC Davis analysis of the NFIP data is on-going, and interesting patterns are emerging in the California data and the full US dataset.  Two conclusions have jumped out of the analyses completed to date that seem timely and pertinent to state and federal policy discussions.


Table 1. NFIP policies in California counties, as of 10/31/2016 , tabulated by total number of policies (left) and by total county insurance coverage (right).

Repetitive Losses

Thirty years after establishment of the NFIP, the Higher Ground report (NWF, 1998) singled out a problem –a small number of “repetitive loss” properties were receiving repeated insurance payouts, accounting for a disproportionate share of all NFIP outlays.  At that time, just 2% of all insured properties drew 40% of all disaster payments.  One property in Houston received 16 payouts totaling $806,591, more than seven times the structure’s value.

Our UC Davis research group, working with the Natural Resources Defense Council (NRDC), also looked at repetitive flood-loss properties.  New FEMA data show that 30,369 properties (0.58% of NFIP policies) – designated “Severe Repetitive Loss” (SRL) properties – are responsible for 10.56% of all claims.  (Our request to FEMA for its broader “Repetitive Loss” [RL] database is currently pending.)  Current SRL properties include structures that have made up to 40 flood-damage claims each.  One house in Alabama, valued at $153,000, has received $2.25 million in NFIP payouts – more than double the worst ratio in 1998 (the Houston property discussed above).

NRDC has proposed incentives to remove repetitive-loss properties from the NFIP insurance and the nation’s floodplains.  Hayat and Moore (2015) propose “property owners should agree in advance not to rebuild following floods that cause substantial damage and, instead, to accept a government buyout of their property and relocate. In exchange, they would receive a discount on their federal flood insurance coverage….”  We are now working to identify communities with repeated flood damages, high densities of designated SRL properties, and high socio-economic need (low income levels and/or high social vulnerability, Cutter et al., 2013).  Implemented carefully, such proposals could reduce the most burdensome flood-loss properties, while improving insurance affordability and transitioning low-income residents off the floodplain.

Of >30,000 SRL properties nationwide, 393 are in California. At the top of the list, Louisiana has 7223 and Texas 4889 SRL properties.  Nonetheless, the California SRL properties amount to $56.7 million in cumulative payments.  More detailed examination suggests localized issues in California – Sonoma County ranks 20th among communities nationally for largest number of SRL claims (977) and 25th for total SRL payments ($27 million).  The Sonoma County Hazard Mitigation Plan (Sonoma County, 2011; hmp_2011/) acknowledges that “payments to Sonoma County for repetitive flood losses are greater than the next nine highest [California] communities combined and account for … 34% of total state dollar outlays.”  California leads the nation in many metrics of flood protection and resilience, but local problem areas may require additional guidance, resources, and/or oversight.

NFIP Net Payers and Net Recipients

Flood insurance requires that many participants pay into the program in any given year so a few may draw funds in times of extreme need.  Health, auto, and home insurance also may include low-risk participants who persistently pay into the program pooled with higher-risk participants.  These variations are sometimes addressed by setting premiums proportional to estimated risk, but sometimes the risk factors are too difficult to quantify or are simply accepted as a subsidy to some in the insurance pool.

NFIP is rife with subsidies, such as low “grandfathered” premiums for homes in floodplain and coastal flood zones before the start of the program.  Or repetitive-loss structures that resist attempts to mitigate or relocate off the floodplain.  Our analyses of NFIP historical policy and claims data suggest that such imbalances and subsidies also exist at a state-to-state scale, and should be examined carefully.

The UC Davis analysis examined 1994-2014 NFIP claims and premiums data.  Calculated as ratios of total premiums paid to total claims, some US states emerged as long-term recipients of NFIP funds and other states as long-term payers into the program (Figure 1).  Over these 21 years, Mississippi policyholders paid 18 cents per dollar of flood insurance pay-outs, whereas Wyoming policyholders paid $32 in premiums for every $1 in claims.  The 10 largest net recipients of NFIP claims payments are tabulated (Table 2) as well as the 10 largest net “donor states” (Table 3).

NFIP net claims.png

Fig. 1. Ratios of claim payments to policy premiums during 1994-2014, by state (in 2015 dollars).  Alaska, Hawaii, and US protectorates are not shown.

Among the top-ten recipients, several states show claims that largely result from a single flood event: Hurricane Katrina in 2005 for Louisiana, and Hurricane Sandy in 2012 for New York and New Jersey.  Such catastrophic events are the nature of flooding – with average recurrence of damaging events spanning decades to centuries – and are the primary purpose of insurance.  To consider the one-off effects of any particular flood event, we removed the year of greatest claims for each state, and re-ranked the resulting ratios (right side of Table 2).  The resulting list, which includes North Dakota, Alabama, and Pennsylvania, captures states with more persistent patterns of flood damages and NFIP claims.

Table 3 tabulates the 10 states with the lowest total flood-damage claims calculated proportional to the premiums those states paid into NFIP.  Also shown (Table 3, right) are the 10 states with the largest dollar differential between claims and premiums.  In both cases in Table 3, the effect of removing the largest claims year for each state was minimal.


Table 2.  Largest net recipients of NFIP flood payouts, calculated proportional to cumulative premiums by state.  Also shown are the largest net recipients with the year of greatest flood year removed for each state. 


Table 3.  Largest net payers into NFIP, calculated as the ratio of cumulative payouts to premiums (left) and as a net dollar differential between payouts and premiums (right).  


A major policy question is whether “net payer” states have just been lucky (avoided major floods in the last 21 years), or rather has flood risk in these states been overestimated or successfully managed or reduced, such that these states subsidize the larger insurance pool?

Several mechanisms could explain why some US states may have better managed flood risk.  These mechanisms are the subject of on-going research.  If verified, these states may look to remedies that credit their investments, attention, enforcement and/or more diligent stewardship of their floodplains and coastlines.  However, the penalty for getting the question above wrongly may be severe.

Preliminary analyses suggest that California consistently pays more into NFIP than is justified by historical damage claims.

Since 1994, NFIP damage payouts in California total just 14% of premiums collected.  The three most damaging flood years in NFIP history have all occurred since 1994, and yet only the worst year of California flooding (1995) has cumulative NFIP payouts exceeding premiums collected statewide, and then only slightly ($1.35 in claims per $1.00 of premiums).  Furthermore, a community-scale analysis of payout/premium patterns shows that only 18 of California’s 538 jurisdictions had cumulative NFIP payouts that exceeded premiums collected in that area.  119 jurisdictions, or 22% of California’s total, paid NFIP premiums over the full duration of study, but had zero payouts. One California region – the Central Valley — has been particularly outspoken about perceived unfairness in costs and restrictions imposed by NFIP (e.g., Government Accountability Office, 2014).  Although we do not accept all claims of “floodplain exceptionalism” suggested by some Central Valley residents and growers, initial analyses suggest high NFIP premiums relative to historic claims – payouts are just 9% of cumulative Central Valley premiums.  More detailed analyses of agricultural structures and flood losses are needed.

Policy Recommendation:  California should explore a state flood insurance program, with savings invested in long-term risk reduction.

Current federal law requires that home and business owners with federally-backed mortgages must carry flood insurance.  However, this mandatory insurance need not be through NFIP.  In the past 2-3 years, more private insurers have selectively offered flood coverage.  There is broad interest in privatization of flood insurance, including pending federal legislation (HR 2901 and S 1679), but concern exists from floodplain and flood-risk experts that privatization will reduce FEMA funding for floodplain mapping and mitigation activities.  Perhaps more concerning is that private insurers will “cherry pick” flood policies now overpriced by NFIP and leave the NFIP as the insurer-of-last-resort, holding only grandfathered, repetitive-loss, and other “actuarial dogs” imposed by legislative mandate.  This outcome would overwhelm NFIP with unsustainable debt.

Rather than relying on privatization to solve its flood-insurance inequities, California should move quickly to stake its place in this arena.  This recommendation was earlier made by California’s Department of Water Resources in 2005: “Examine existing flood insurance requirements and consider the creation of a ‘California Flood Insurance Fund,’ … to compensate property owners for flood damage” (DWR, 2005).  California should consider acting before private interests make state action untenable.  Interesting public-private solutions are possible, such as partnering with private reinsurers to hedge the risk from low-probability, high-magnitude catastrophic floods.  Many services funded by NFIP, such as flood-hazard modeling and mapping, are being done across California using tools half-a-century ahead of FEMA-funded contractors.  California also leads the country in implementing flood mitigation measures, like bypass channels and levee setbacks, that simultaneously reduce flood risk for surrounding areas, enhance riparian and wetland habitats, promote agriculture, provide recreation, and support groundwater recharge.  In implementing its own flood insurance program, California would be in a position to address many of the shortcomings of NFIP, remedying important issues like repetitive-loss properties, residual risk behind levees, and sovereign liability for flood damages.

California is in a position to do what it does best – not follow the nation, but lead.  The state has the expertise, and the need, to set new precedents in sustainable flood-risk management.

Nicholas Pinter is the Roy Shlemon Professor of Applied Geosciences in the Department of Earth and Planetary Sciences and an affiliate of the UC Davis Center for Watershed Sciences. Rui Hui is a postdoctoral researcher with the Center for Watershed Sciences. Kathleen Shaefer is a prospective graduate student at UC Davis, and previously worked as a Regional Engineer for flood projects with FEMA Region IX.

Further Reading

Cutter, S.L., C.T. Emrich, D.P. Morath, and C.M. Dunning, 2013.  Integrating social vulnerability into federal flood risk management planning.  Journal of Flood Risk Management, 6: 32–344.

California Department of Water Resources (DWR), 2013.  California’s Flood Future: Recommendations for Managing the State’s Flood Risk.

Governmental Accountability Office (GAO), 2014.  National Flood Insurance Program:  Additional Guidance on Building Requirements to Mitigate Agricultural Structures’ Damage in High-Risk Areas Is Needed, GAO-14-583.

Hayat, B. and R. Moore, 2015.  Addressing affordability and long-term resiliency through the National Flood Insurance Program.  Environmental Law Reporter, 4-2015.

National Wildlife Federation, 1998.  Higher Ground: A Report on Voluntary Property Buyouts in the Nation’s Floodplains.

Rand Corporation, 2006.  The National Flood Insurance Program’s Market Penetration Rate: Estimates and Policy Implications.

Posted in flood | Tagged , , , | 11 Comments

How engineers see the water glass in California

Engineering a water glass at 50 percent. Source:

Engineering a water glass at 50 percent. Source:

How do engineers see the water glass in California? Mostly the same as they did four years ago when this blog was first posted, though with today’s drought the glass is perhaps down to a quarter full — or three-quarters empty. 

By Jay R. Lund

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

Civil engineer: The glass is too big.

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

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

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

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

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

Southern California water engineer: Can we get another pitcher?

Northern California water engineer: Who took half my water?

Consulting engineer: How much water would you like?

Environmental engineer: I wouldn’t drink that.

Water reuse engineer: Someone else drank from this glass.

Groundwater engineer: Can I get a longer straw?

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

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

Further reading

Munroe, Randall. Glass Half Empty.

Posted in Uncategorized | Tagged , | 6 Comments

The Coming Droughts of California in 2017 – November 27, 2016

By Jay Lund

California is a big diverse place.

California probably will experience droughts this year of different types in different places, and no drought at all in some places, simultaneously.  Even if conditions this year are very wet, with flooding, parts of California will have drought issues. (This is what makes California a great place to work on water problems.)

The first two months of this new water year have been wetter than average in the north and much drier than average in the south.  But it is still early days.

Reservoir and Groundwater Storage Conditions

Reservoir storage in California is now about 2.5 million acre-feet below historical averages for this time of year.  (This is 0.8 maf better than 2 months ago.)  Some major reservoirs are below average, particularly Oroville, Trinity, San Luis, New Melones, and the Tulare Basin reservoirs.  Cachuma Reservoir near Santa Barbara is in the worst shape at 7% of capacity or 10% of average storage for this time of year.

Groundwater will be recovering in northern parts of California, with less recovery in large parts of the southern Central Valley.  (Can anyone suggest a set of online well elevation records in different parts of the Central Valley to create a groundwater storage index?)

October was a nice wet month, so soil moisture in much of the Sierras and Central California is improving, but remains in drought conditions (worsened by unusually high temperatures).  Conditions for forests and native fishes remain depressed and will see drought impacts for years after hydrologic conditions improve.

This seemingly bad situation is substantially better than in this time a year ago.  Something to be thankful for.


Major reservoir storage in California, 26 November 2016

Precipitation Conditions

North of the Delta, so far we have above average precipitation and improving storage in most Sacramento Valley reservoirs.  In the San Joaquin Valley, this water year’s precipitation is about average so far.  But further south, the Tulare Basin has less than 50% of average precipitation so far this water year.  And temperatures remain higher than average.  So far, no snowpack – it is still a bit early.

Thoughts for the coming drought year

So far, overall drought conditions are mostly improving, but unevenly.  We won’t really know how wet this year will be until late March.  In October, this blog looked at overall drought conditions from several perspectives and statistical projections for the new water year.  (This month’s election reminded us of the reliability and unreliability of statistical projections.)

Even if this year is wet, parts of California will experience drought or residual effects from five years of drought.  The California Drought of 2017 will likely take several forms:

  1. Dry residential and community wells drought, affecting rural areas with lowered groundwater tables. Many of these household wells and small systems are in a precarious state even in wet years.
  2. Drought of surface irrigation water. Here surface water is unavailable and farmers mostly increase groundwater pumping, often at a higher cost and increasing regional groundwater depletion. This drought is more likely south of the Delta.  Less surface being less available than irrigation demands south of the Delta is now a normal condition, due to a host of hydrologic, infrastructure, groundwater sustainability, economic and environmental factors, worsened by drought.
  3. Higher groundwater pumping cost drought. Even if this year is wet, many areas that pump groundwater will still face higher pumping costs for some years or longer from the drought’s cumulative groundwater depletions.
  4. Forest drought (including snow drought). Here, lack of soil moisture or its more rapid depletion with higher temperatures affects forest ecosystems.
  5. Ecosystem drought. Problems for some fish are likely to continue even if the year is wet, due to drought-depletion of some native fish populations.  Dry conditions could also affect waterfowl. A drought of cold water in some reservoirs might affect both fish and farmers disrupted by reoperation of reservoirs.
  6. Urban drought. So far, most urban areas have pretty healthy water supplies.  The big exception is Lake Cachuma in the Santa Barbara area, now at 10% of its long-term storage for this time of year.
  7. We could easily see some drought surprises. The wet season is still young. Welcome to California water, where anything can happen.

It is best to prepare for another drought year (and prepare for floods as well).

Here are some web sites to watch, mostly from the California Department of Water Resources’ fine California Data Exchange Center (CDEC) at

Reservoir levels:

Snowpack (none yet):



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

A neat reading

Posted in California Water, Drought | Tagged | 5 Comments

Human Use of Restored and Naturalized Delta Landscapes

By Brett Milligan, Assistant Professor, UC Davis Landscape Architecture and Sustainable Environmental Design and Alejo Kraus-Polk, PhD Geography candidate, UC Davis


Ponds #9-13 of White Slough Wildlife Area. Ponds are borrow pits from building I-5 while beginning a Delta peripheral canal. When the peripheral canal was voted down in 1982, these lands were retained by California’s Department of Fish and Wildlife for “interim” management, today as part of the White Slough Wildlife Area for fishing, hunting, wildlife viewing and other recreational activities. Photo by Brett Milligan.


Restored Landscapes in the California Delta: Current and planned EcoRestore projects and other restoration projects completed, in progress or in planning. Data from the California Department of Water Resources and EcoAtlas. Map by Brett Milligan and Prashant Hedao.

Current legislation and plans for the California Delta call for restoring tens of thousands of acres of aquatic and terrestrial habitat, which will require large changes in land uses and cultural patterns.  In addition to planned ‘restoration’, unplanned ‘naturalization’ also occurs in the Delta, from the flooding of islands or the abandonment of previously managed land.  These newly feral or semi-wild landscapes will remain subject to human use and give rise to new scientific, economic, and recreational uses.

We recently completed a study of how restored and naturalized landscapes are being used by people, the effects of those uses, and how those uses might be better planned.  We surveyed or interviewed more than 100 land managers, scientists, landowners, law enforcement personnel, agency representatives and Delta residents and reviewed existing Delta planning literature, field work and case studies. In general, our research supports advancement of an ecosystem reconciliation approach, which seeks synergies between ecosystem needs and the desires of those who live, work and play in the Delta, now and in the future.

We found that:

Restored and naturalized landscapes are strongly affected by human use, presence and management.  These landscapes reflect their former domesticated states and uses, which were mostly agricultural. This newly feral quality, along with accelerated rates of climate change, ensure that these ‘restored’ landscapes will be novel and unprecedented ecologically.  These landscapes are human places as much as they are ecosystems and have a long history of use for subsistence, recreation, illicit and unregulated activity, and more recently, for science.  Combined with the extensive urbanization surrounding the Delta, human uses of these landscapes will remain diverse and pervasive.

Restored and naturalized landscapes are often subject to multiple and conflicting uses and values.  Experiences and cultural practices are typically marginalized in restoration planning, but have understudied effects on these landscapes. Politics, laws, accessibility, amenities, ways of living and territoriality all affect what these places will become.  There are different values related to the evolving Delta, beyond science and restoration goals. Diversity of values should be included in planning, design and management, as they affect the performance of restoration efforts.


Entrance Gate to Liberty Island. Photo by Brett Milligan.

Reconciling human uses with ecological restoration will require more comprehensive planning and design.  Plans and designs should serve multiple beneficiaries, both non-human and human.  Regional connectivity (landscape networks) also matters in terms of access and ecological functions.  Restoration planning and design should seek community involvement and stakeholder participation, critical for long term success.  Human uses should be integrated into restoration planning from the beginning, rather than as an afterthought, as these uses can increase the value and support for these projects, contribute to the local and regional economy and deter undesirable and unsanctioned uses.

Funding for recreation and human uses in restoration planning is an important long term investment, and is recommended in the Delta Plan.  Design and management choices at the beginning of a restoration project have a strong bearing on future relationships and conditions.  We should design and plan for pleasure, aesthetics and accommodate diverse user experiences, to build stronger constituencies and public appreciation.  Not accounting for public use and place values tends to lead to problems and unintended uses.  Designing for human uses at the outset of a project will cost more initially, but should reduce long term conflicts among the objectives of management, enforcement and desires of users.  Ecological restoration initiatives, such as Ecorestore, should continue to integrate and fund participatory restoration planning, such as the former Delta Dialogues and Delta Restoration Network projects and the current Delta Conservation Framework.


Floating Duck Blind, Franks Tract. California State Parks manages a duck hunting program on Franks Tract. Hunters apply for permits to build blinds at specific coordinates within a grid of evenly spaced locations across the lake. The blinds must be removed at the end of the hunting season. Photo by Brett Milligan.

Human uses of restored landscapes should be integrated into adaptive management.  The Delta Independent Science Board’s Adaptive Management review posits that a, “more holistic and integrated approach to science­ based adaptive management in the Delta is needed to face both current and future challenges” (DISB 2016).  Human uses can be compatible with restoration objectives through effective and creative adaptive management.  However, like the dynamic nature of the Delta’s ecology, human uses are not determinate, varying with geographic contexts and across time. Therefore, human use studies specific to the Delta’s landscapes — scientific, recreational, etc. — should be done regularly to better inform management.

The public is an overlooked asset and advocate for restoring and monitoring Delta landscapes.  The Delta’s novel ecologies and efforts to guide them should be highlighted in Delta literature, marketing and advertising.  In particular, citizen science offers a range of win-win methods to collect broader low-cost monitoring data.  It also offers science an avenue for greater public acceptance and understanding (McKinley et al. 2015).  Although citizen science is almost non-existent in the Delta it is widely and successfully practiced in the San Francisco Bay Area.  Experimentation with citizen science should be a Delta science priority.  We should also experiment with the variety of interactive, real time, and geolocative digital media available to users and visitors of the Delta. There is much potential for the creative use and application of such media for fostering awareness and stewardship of Delta restoration efforts.


Native plant restoration. Native plant hedgerow maintained Stone Lakes National Wildlife Refuge by the Sacramento Tree Foundation, Winter, 2015. Hedgerow provides habitat and a buffer and natural fence to discourage trespassing onto adjacent, private farmland. Photo by Brett Milligan.

Our research suggests the need to shift how restored Delta landscapes are considered in planning, policy and design.  We advocate for including human presence integrally in these landscapes.  Doing so will make restoration efforts more realistic and effective.

Reconciling human uses with restoration objectives requires a broader view of stewardship.  Enhancing and planning for human use experiences could help reconcile multiple issues of concern.   Integrated adaptive management efforts with adequate resources should play a role in the present and future of restored and naturalized Delta landscapes.

This shift in approach is timely as restoration efforts gain momentum and expand.  A 2016 DISB report on adaptive management and the IEP Delta Science Agenda both signaled the need to integrate human factors in designing for ecological recovery in the Delta.  Yet there is a considerable void in the literature and in stakeholder conversations on the topic.  This study provides a rationale for why human dimensions of adaptive management are needed in restoration and broader management efforts, and why giving human dimensions more rigorous consideration can assist in meeting these goals.

Further reading

Human Use of Restored and Naturalized Delta Landscapes Report:
Human Use Report Executive Summary
Human Use Report for screen viewing (spreads)
Human Use Report for printing
Human Use Report Appendix

DISB. 2016. “Improving Adaptive Management in the Sacramento-San Joaquin Delta.” DISB.

McKinley, Duncan C., Abraham J. Miller-Rushing, Heidi L. Ballard, Rick Bonney, Hutch Brown, Daniel M. Evans, Rebecca A. French, et al. 2015. “Investing in Citizen Science Can Improve Natural Resource Management and Environmental Protection.” Issues in Ecology 19.

Posted in Delta, Planning and Management, reconciliation, Restoration | Tagged , | 5 Comments

Allocating a Share of San Joaquin River Water to the Environment Shows Promise

Source: California Department of Water Resources

Source: California Department of Water Resources

By Jeffrey Mount, Brian Gray, Ellen Hanak, PPIC Water Policy Center, Peter Moyle, UC Davis Center for Watershed Sciences


In September 2016, the State Water Board released its draft plan for new environmental flow requirements in the San Joaquin River watershed. The board’s proposal contains a novel—and controversial—recommendation. Instead of following the traditional approach of setting minimum flows to meet specific environmental needs at specific times of the year, the board proposes to allocate a block of water each year to improve habitat for fish and wildlife in the lower San Joaquin River and its tributaries—the Stanislaus, Tuolumne, and Merced.

As we have argued in several recent reports, assigning a block of water to the environment has numerous advantages over the traditional regulatory approach. Done well, it could improve ecosystem performance and the efficiency of environmental water use, while reducing uncertainty for other water users.

Here we outline the essence of the board’s proposal and describe its strengths and areas for improvement. We conclude with some suggestions for how these ideas could be incorporated fruitfully into settlement negotiations with stakeholders in the watershed.

The board’s proposal: Allocating a share of water for the environment

Native fishes in the Lower San Joaquin River and its tributaries—particularly salmon and steelhead—have been declining for decades. The board has authority to address this decline by setting flow requirements to protect beneficial uses of California’s waters. This authority derives from a variety of California laws that are not dependent on either the federal Clean Water Act or the Endangered Species Act.

For fish, the board traditionally sets minimum flow standards tailored to meet the requirements of specific life stages of each of the protected species (e.g., pulse flows to facilitate migration up and down the river, cold water for eggs and young fish). These flows are made available through a combination of releases from reservoirs and limitations on diversions by other water users.

The proposed new approach is to allocate a portion of the February-through-June “unimpaired flow” on the Stanislaus, Tuolumne, and Merced tributaries to native fish. Unimpaired flow is the volume of water that would be present in the tributaries without reservoirs or diversions.

The plan proposes that an average of 40% of this flow—with a range of 30-50%—be assigned to meet environmental objectives. We have no position on the merits of this proposed share, which is likely to be a matter for negotiation on each tributary.

More important is the flexible way that environmental managers could use this water. Under the proposal, they could shift flows as needed for different hydrologic conditions or locations to meet biological goals for protected species. This could include storing water for pulse flow releases—such as to improve water quality or provide migration cues for fish—and holding water until late summer to bolster cold water releases from reservoirs.

Why this approach is a good idea

The board’s proposal to allocate a flexibly managed block of water to the environment is an improvement over the traditional setting of minimum flow standards in three ways:

  • Efficiency: The block approach allows for better use of environmental water to benefit fish. Managers can more easily adapt to changing conditions such as droughts and floods, time flow releases for maximum effect, vary the way they apply water from year-to-year, and more nimbly respond to new biological and ecological information. This would increase the efficiency of environmental water use while also improving its effectiveness.
  • Predictability: A block of water is simple, transparent, and easier to incorporate into environmental and operations planning.  Assigning a specific quantity of water to environmental uses would give more certainty to other water users, because they would know the percentage of unimpaired flow available to them.
  • Shared responsibility: Allocating a flexibly managed block of water to environmental uses would ensure that the environment is better integrated into the water rights system. Environmental water managers would have a seat at the table in water management, deciding how best to use their allocation just as other water users do, and the environmental water block would share equally in abundance and shortage along with other beneficial uses.

What would make this approach even better

In addition to this novel approach to establishing flow standards, the draft plan encourages stakeholders and interested parties to negotiate settlements that they would submit to the board for approval. Such negotiations are a good way to harness local knowledge, creativity, and cooperation.

We recommend that negotiators and the board retain the idea of allocating a block of water to the environment and consider several improvements:

  • Allow carryover: The draft plan requires that all environmental water be used in the same water year. To enhance efficiency and to hedge against drought, it should be possible to store some environmental water in surface reservoirs or groundwater basins (with rules to avoid impacts to other users). A good example of the benefits of integrating groundwater and surface water storage with environmental flow management comes from the Yuba River watershed in northern California.
  • Allow trading: Environmental water efficiency also would be enhanced if the plan explicitly allowed the buying and selling of this water. A good example comes from Australia, where environmental managers regularly lease some of their water to fine-tune flow management in different catchments. Some revenues from leasing are also used to support ecosystem investments.
  • Encourage augmentation: The existence of a well-managed environmental water budget would present an opportunity for better employing conserved urban and agricultural water for environmental purposes. Allowing the budget to be easily augmented with water acquired on a permanent, long-term, or temporary basis through voluntary purchases or donations would increase resources for environmental management.
  • Assign responsibility: The proposed governance structure for environmental water management is a large, multi-party committee of regulatory and planning agencies, project operators, water users, and other stakeholders (Draft Plan, Appendix K, page 32). This structure is cumbersome and lacks the independence and flexibility needed to administer the block of water in a timely fashion. The revised plan should create an environmental water manager—perhaps similar to the environmental water holder in Victoria, Australia—with authority and staffing to administer the environmental water for defined biological objectives.
  • Improve planning: The long-range biological goals and objectives—beyond improving salmonid populations—are not well articulated in the current plan. Management of the Stanislaus, Tuolumne, and Merced tributaries needs an overarching biodiversity plan that takes a broader, ecosystem-based approach and defines how the environmental water allocation would benefit salmonids as well as other riverine, riparian, and wetland species. The plan should achieve multiple environmental benefits from the water, focusing on different priorities in different types of water years. Such a plan could be developed relatively quickly, based on available scientific information and with input from stakeholders. The biodiversity plan should be revised every 7-10 years, based on improvements in scientific understanding of ecosystem performance. Victoria, Australia provides a model for developing pragmatic, ecosystem-based plans to maximize the benefits of environmental water.
  • Monitor and Adapt: It is critical that management of the environmental water allocation be supported by a robust, transparent, and science-based monitoring program. This program should report to the environmental water manager, who would use the information to guide annual allocation and use decisions, adaptation and management experimentation, and long-term planning and evaluation.  Funding this effort may require pooling of resources among agencies and water users.


The board’s proposal to use a percentage of unimpaired flow as an environmental standard and budget for the Stanislaus, Tuolumne, and Merced tributaries has generated a great deal of controversy in the water-user community. While this is understandable, we encourage all interested parties to carefully examine the merits of this approach and to consider its compensating advantages. Block allocations of environmental water—flexibly managed and supported by science, sound governance, and planning—can be an effective tool for achieving the twin goals of ecosystem protection and water supply reliability.  Negotiating settlements that seek to achieve multiple benefits from blocks of environmental flows is a promising direction for using California’s water more efficiently and effectively.

Further Reading

California State Water Resources Control Board. 2016. Draft Revised Substitute Environmental Document in Support of Potential Changes to the Water Quality Control Plan for the Bay-Delta: San Joaquin River Flows and Southern Delta Water Quality.

Escriva-Bou, A., H. McCann, E. Hanak, J. Lund, and B. Gray.  2016. Accounting for California’s Water. Public Policy Institute of California.

Gray, B., E. Hanak, R. Frank, R. Howitt, J. Lund, L. Szeptycki, and B. Thompson.   2015. Allocating California’s Water: Directions for Reform. Public Policy Institute of California.

Lund, J., E. Hanak, B. Thompson, B. Gray, J. Mount, K. Jessoe. 2014. Why give away fish flows for free during drought? California Waterblog.

Lund, J. 2015. Urban water conservation for birds.  California Waterblog.

Mount, J., B. Gray, C. Chappelle, J. Doolan, T. Grantham and N. Seavy. 2016. Managing Water for the Environment During Drought: Lessons from Victoria, Australia. Public Policy Institute of California.

Posted in California Water, Uncategorized | Tagged , , , | 7 Comments

The North Delta Habitat Arc: an Ecosystem Strategy for Saving Fish

Cache Slough sunrise, April 2013. Photo by P.B. Moyle

Cache Slough sunrise, April 2013. Photo by P.B. Moyle

Peter Moyle, John Durand, Amber Manfree.  Center for Watershed Sciences, University of California, Davis.

Delta native fishes are in desperate condition. Over 90% of fish sampled by diverse means belong to non-native species.  Native species such as delta smelt are on a trajectory to extinction.  If we are going to reverse this trend, we need to recreate a functioning estuary. This in turn requires more than a piecemeal collection of restoration projects, but an ecosystem-based plan of action, which we present here.

First, we remind you of some basic realities about the Delta:

  • The Delta is and will continue to be a central node in California water supply system, which requires moving Sacramento River water through the Delta to pumping plants.
  • Upstream diversions prevent a substantial amount of water from reaching the Delta.
  • There will be major changes to the Delta from multiple factors, including sea level rise, earthquakes, climate change, and (perhaps) methods of water export.
  • Areas of the Delta dominated by Sacramento River flows are very different ecologically from those on the San Joaquin side.
  • The Delta is an increasingly hostile place for native fishes because of the combination of large-scale habitat change, alien species, and changed hydrodynamics.
  • The Delta as a whole, but especially the south and central Delta, no longer functions well as part of an estuary, because changes in flow alter the dynamic upstream-downstream gradient of habitat characteristic of estuaries.

Regardless of ‘fixes’ proposed for the present cross-Delta water delivery system, major projects to provide habitat for declining native species are needed.  Many projects are already underway or planned. These are mostly in the north and west Delta where more opportunities are provided by availability of suitable land elevations and fresh water from the Sacramento River.


The Delta, showing the North Delta Habitat Arc.

Here we propose the conceptual basis for a Grand Strategy to create an inter-connected series of habitats, mostly tidal, in this region. In some respects this strategy is already underway, but it lacks a unified conceptual, scientific, institutional, and applied approach.

This Grand Strategy creates an arc of habitats connected by the flows of the Sacramento River.  The upstream end of the arc is the Yolo Bypass, and the arc continues through the Cache-Lindsey Slough-Liberty Island region, down the Sacramento River including Twitchell and Sherman Islands, and into Suisun Marsh (See figure). The Cosumnes River-Stone Lakes area would act as a connected floodplain region.  We refer to this arc the North Delta Habitat Arc but it could perhaps be called the Reconciliation Arc, recognizing the highly altered nature of the habitats, the need for continuous management, and their significant compatibility with farming and other activities.

Here are some of current features and actions occurring in the Arc:

Yolo Bypass.  This is the place where we are learning how farmed floodplains can become major contributors to conservation of fish and wildlife. Future projects are likely to include gates on the Fremont Weir to allow annual flooding on some parts of the Bypass, especially in miniature floodplains along the Toe Drain, on the east side of the Bypass.  Re-establishing a natural connection between Putah Creek and Sacramento River through the Bypass should support re-establishment of runs of salmon and other migratory fish in the creek.  Water flowing through Bypass, even as small pulses, also has potential to be a source of food and nutrients for pelagic fishes in the Delta.

North Delta.  The Lindsey-Cache Slough-Liberty Island area is widely regarded as prime real estate for restoration projects, in part because the natural drainage patterns still exist on the landscape and because of its connections with the Sacramento River.  Examples of on-going projects include the reconnection of historic tidal sloughs to Calhoun Cut, the development of a tidal marsh ‘from scratch’ as mitigation habitat, and Liberty Island Ecological Preserve.

Sacramento River.  The Sacramento River as it flows through the Delta is THE major corridor for fish migration:  four runs of Chinook salmon, steelhead, American shad, striped bass, delta smelt, longfin smelt , splittail, green sturgeon, and white sturgeon.  Maintaining flows and water quality is important for all these species.  It is likely that complex, vegetated edge habitat is very important for juvenile fishes moving downstream and perhaps for spawning of delta and longfin smelt.   The restoration of large tracts of tidal marsh on Twitchell and Sherman Islands is likely to benefit migratory species of both fish and birds, as well as to reverse subsidence and perhaps provide ‘food’ for larval and juvenile fishes through export to main channels.  We also envision using ponds within these islands to support populations of Sacramento perch and other native species.

Suisun Marsh.  Suisun Marsh is connected to the Sacramento River by Montezuma Slough, which has large tidal gates near its upstream end.   The tidal gates regulate salinities in the Marsh, keeping conditions fresher during late summer and fall. The high potential of Suisun Marsh to support native fishes is increasingly being recognized.  New projects are being started or proposed, such as finding ways to manage duck hunting clubs for both fish and ducks, creating tidal habitat that mimics conditions in remaining ‘natural’ tidal sloughs, and making Roaring River Slough into a flow-through system, rather than just a dead-end water delivery system for duck clubs.

These areas each have their own distinctive characteristics and faunas. Collectively, the many projects should be regarded as a large-scale example of reconciliation ecology, where new habitats are created and closely managed by people to meet specific goals. The biota of these new habitats is a mixture of native and non-native species that together form novel ecosystems.

Viewing the Arc as a large inter-connected and reconciled ecosystem should help us to:

  • Manage projects to benefit a full range of life history stages for key species. For example, splittail spawn on floodplains but rear in brackish tidal marsh, so they need the entire system to support their life history.
  • Coordinate management of restoration projects with water project operations.
  • Manage the system in a changing climate: longer droughts, bigger floods, and warmer temperatures.
  • Restore tidal marshes as sources of food for pelagic fishes such as delta smelt.
  • Compare outcomes of different restoration strategies.
  • Assess how tidal marsh restoration projects affect tidal flow in projects, given that total tidal energy is more or less fixed.

We recognize that we are essentially recommending that reconciliation efforts be focused on about one third of the Delta, especially for fishes.  In the Central and South Delta, the realm of subsided, riprap-ringed islands and major pumping plants, it is hard to see much future for native fishes, although fisheries for alien fishes such as largemouth bass will continue to thrive. We will develop these concepts further in future blogs.

Further reading:

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 EstuarySan Francisco Estuary and Watershed Science, 14(2). jmie_sfews_31667. Retrieved from:

Quiñones, R.M and P.B. Moyle. 2014. Climate change vulnerability of freshwater fishes in the San Francisco Bay Area. San Francisco Estuary and Watershed Science 12(3). doi:

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

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. San Francisco: Public Policy Institute of California. Available at

Moyle, P.B.  2013 Ten realities for managing the Delta.  California Water Blog. Center for Watershed Sciences, UC Davis. February 26, 2013.

Moyle. P.B. W. Bennett, J. Durand, W.Fleenor, J. Lund, J.Mount, E. Hanak, and B. Gray. 2012. Reconciling wild things with tamed species- a future for native fish species in the Delta. California Water Blog. Center for Watershed Sciences,  June 15, 2012.

Moyle, P. B., W. Bennett, J. Durand, W. Fleenor, B. Gray, E. Hanak, J. Lund, J. Mount. 2012. Where the wild things aren’t: making the Delta a better place for native species. San Francisco: Public Policy Institute of California. 53 pages.

Moyle, P.B. 2011. Reconciliation or extinction- the future of California? California Water Blog. Center for Watershed Sciences, February 8, 2011

Lund, J., E. Hanak, W. Fleenor, W. Bennett, R. Howitt, J. Mount, and P. B. Moyle.  2010. Comparing futures for the Sacramento-San Joaquin Delta. Berkeley: University of California Press. 230 pp.

Posted in Delta, Uncategorized | Tagged , , | 5 Comments