Reconciling conservation and human use in the Delta

This view of a duck hunting club in Suisun Marsh shows both a highly modified environment and reflects its potential for being managed as a reconciled ecosystem. Photo by P Moyle.

This view of a duck hunting club in Suisun Marsh shows both a highly modified environment and reflects its potential for being managed as a reconciled ecosystem. Photo by P Moyle.

By John Durand, Peter Moyle, and Amber Manfree 

In a previous blog, we presented a Grand Scheme for habitat conservation in the North Delta Arc (the Arc). This follows up on our earlier broad vision for recreating a Delta more friendly to its native species.  In this essay, we give philosophical and historical reasons to approach habitat conservation on the regional scale of the Arc, using reconciliation ecology as our guide.

The Sacramento-San Joaquin Delta has been extensively altered over the past 150 years. Major changes include manipulation of river flows, alien species invasions, conversion of wetlands to agriculture and, most recently, climate change. Changes have been incremental and slow enough that successive generations of Delta residents, fishermen, scientists, and managers have not seen the full extent of transformation. Each generation assumes the conditions they encounter are not much different from those of the recent past. This problem of slowly shifting baselines means that our understanding of historical conditions shifts with changing conditions, because the change is difficult to accept and because we cannot directly observe what conditions were like in the more distant past (Pauly 1995; Papworth et al. 2009).

A recent review of anthropological studies, early travelogues, and scientific surveys of the Delta gives a better sense of the transformation. The Delta originally was a place where the sky darkened with migratory waterfowl in fall, where salmon runs crowded tributary rivers, tule elk browsed on oak-topped natural levees, and delta smelt were a common prey for fishes and birds. Flows in the Sacramento and San Joaquin Rivers were highly variable, but predictable in pattern, with winter floods and summer droughts. Such aspects of the historic landscape were gradually lost with marsh reclamation, damming, levee construction, water diversions and pollution from mining, agriculture, waste water and urban runoff. It is impossible to restore natural conditions—little quality habitat remains, connectivity among habitats has been lost, and many historically abundant species are extinct or their populations are greatly reduced in number.  Native species have been largely replaced by alien plant and animal species such as largemouth bass, Mississippi silversides and Brazilian waterweed. These new arrivals are abundant because they are adapted to conditions created by the expanding human-altered landscape.

Governor Brown’s EcoRestore initiative aims to provide habitat restoration projects to reverse the decline of native species and create habitat that functions to support native species . We agree that it is imperative that some of our pre-19th century historic natural legacy be maintained. Given the depth of transformation, restoration to perceived “baseline conditions” is impracticable. That historic Delta is lost.

As a workable alternative, we promote the idea of reconciling current land uses with desirable ecological outcomes. A reconciliation approach to Delta conservation offers opportunities to recapture lost ecological functions that support threatened species. It involves creative management of the current landscape to balance benefits for fish, waterfowl, food webs, and human uses. This idea can help to manage the emergence of novel ecosystems globally, landscapes with new conditions and  combinations of organisms with no historical analogue, but which provide valuable and viable species conservation opportunities, as well as human benefits (Rosenzweig 2003; Hobbs et al. 2006).



This map of North and Central Sacramento-San Joaquin Delta shows reserve networks across the North Delta Arc of Habitat, and the Yolo Bypass Floodplain. Click link or image for detailed information on the reserves. View the full map here.

This approach may involve some dramatic and expensive actions that involve earth moving to recreate marshes and meandering channels. But more often, it involves working with farmers, duck club owners, anglers, and other stakeholders to adjust breaching of levees and the operation of tidal gates to facilitate the movement of water across the landscape.

The Nigiri project on the Yolo Bypass illustrates this concept.  Here, young salmon are raised in rice fields before being released to the Delta and before farmers need to plant, with involvement of local farmers, state agencies, county government, CalTrout, and UC Davis. But Nigiri is not the only reconciliation project in the Delta. In Suisun Marsh, the Potrero Duck Club, historically operated as a private hunting club, is being managed to promote not only water fowl, but as an incubator to create food for the larger aquatic ecosystem. Although these sites differ from historical conditions, they effectively capture the ecological functions of an earlier Delta that are largely lost: they grow and disperse food, act as nursery habitat for young fish and provide food for nearby wildlife. While opportunities to re-create the Delta’s original habitats have faded, opportunities have arisen to create new habitats that serve human needs, provide ecosystem services, and support native fish and wildlife. We see wild lands being integrated with managed lands as the most productive way to create a reconciled Delta.

In future essays, we will explore the use of reconciliation ecology to several important sites in the Delta. These include: Meins Landing, Montezuma Wetlands, Potrero Club, Lindsey Slough, Denverton Slough, Blacklock Pond, Liberty Island, North Liberty Mitigation Bank and Beaver Ponds, Prospect Island and Roaring River.

John Durand is a researcher specializing in estuarine ecology and restoration at the UC Davis Center for Watershed Sciences. He oversees projects in the north Delta Arc of habitat including the Cache Lindsey complex and Suisun Marsh.  Peter Moyle is a UC Davis Professor Emeritus of fish biology and an associate director of the Center for Watershed Sciences. Amber Manfree is a postdoctoral researcher with the UC Davis Center for Watershed Sciences.

Further reading

Hobbs RJ, Arico S, Aronson J, Baron JS, Bridgewater P, Cramer VA, Epstein PR, Ewel JJ, Klink CA, Lugo AE, et al. 2006. Novel ecosystems: theoretical and management aspects of the new ecological world order. Glob. Ecol. Biogeogr. 15:1–7.

Mount J, Bennett W, Durand J, Fleenor W, Hanak E, Lund J, Moyle P. 2012. Aquatic ecosystem stressors in the Sacramento–San Joaquin Delta. Public Policy Inst. Calif.

Moyle PB, Light T. 1996. Fish invasions in California: do abiotic factors determine success? Ecology 77:1666–16670.

Nichols FH, Cloern JE, Luoma SN, Peterson DH. 1986. The modification of an estuary. Science 231:567–567.

Papworth S k., Rist J, Coad L, Milner-Gulland E j. 2009. Evidence for shifting baseline syndrome in conservation. Conserv. Lett. 2:93–100.

Pauly D. 1995. Anecdotes and the shifting baseline syndrome of fisheries. Trends Ecol. Evol. 10:430.

Rosenzweig ML. 2003. Reconciliation ecology and the future of species diversity. Oryx 37:194–205.

Sommer TR, Nobriga ML, Harrell WC, Batham W, Kimmerer WJ. 2001. Floodplain rearing of juvenile Chinook salmon: evidence of enhanced growth and survival. Can. J. Fish. Aquat. Sci. 58:325–333.

Whipple A, Grossinger RM, Rankin D, Stanford B, Askevold R. 2012. Sacramento-San Joaquin Delta historical ecology investigation: Exploring pattern and process. Richmond, CA: San Francisco Estuary Institute-Aquatic Science Center Historical Ecology Program Report No.: 672.

Posted in Conservation, Delta, reconciliation | Tagged , , | 1 Comment

California’s Wettest Drought? – 2017


By Jay Lund

Wet.  After five years of drought, most of California finally has become wet.  The mountains are exceptionally wet and covered with snow.  The state’s reservoirs are fuller than their long term average (with a few exceptions).  Flood control structures are being employed, some for the first time since 2006.

We can now better understand the balance needed for California’s water system – which must operate for many sometimes-conflicting purposes in a climate with wild swings in water availability.  Every year, California must operate for drought, flood, public and ecosystem health, and economic prosperity (or at least financial solvency).

Where is California’s Drought today?

Here are today’s numbers:

2017 will not be a surface water drought for California.  Precipitation and snowpack in much of the state already exceeds that for an entire average water year.  And we still have two months to go in California’s wet season.

Despite these wet conditions, California has remnants of drought, some of which will persist for decades.  Some Central Coast reservoirs remain very low.  Groundwater in the southern part of the Central Valley remains more than 10 million acre-ft below pre-drought levels.  Most of the groundwater deficit is in dry parts of the San Joaquin and Tulare basins, which could take decades to recover – with long-lasting effects on local wells.  The millions of forest trees which died from the drought will need decades to recover, if the warmer climate allows.  Native fish species, already suffering before the drought, are in even worse conditions today.

Drought indicator myths

Given the variety of drought impacts and conditions, many “drought indicators” seem Quixotic and distract policy and management discussions.

The US Drought Monitor is a common drought indicator, based mostly on soil moisture – designed mostly to indicate drought for rain-fed agriculture.  This index is most useful for stress to forests and un-irrigated pasture and crops, which are not California’s biggest drought issues.  California relies much more on large reservoirs and aquifers, which allow crops and cities to survive California’s otherwise beautiful and devastatingly dry summers.  The US Drought Monitor, while a convenient general public service, is misleading for California’s most common drought issues.  National statistics often have such regional problems.

Still less useful, in my mind, is the idea of a “snow deficit” accumulating over drought years.  Snowpack in California physically resets to zero each summer as snow melts – Accumulating snow deficit over years has no physical meaning – and little management meaning.  Real drought deficits do accumulate as aquifer overdraft, reservoir drawdown, dry soil, and cumulative impacts to forest and fish populations, which can take years or decades to recover.  Less snow last year does not reduce water this year except for reduced storage in reservoirs or aquifers – where water deficits are managed and more properly measured or estimated.

Drought indicators should have physical and management meaning, or are more likely to mislead and confuse.  Fortunately, California is more successful with managing droughts than developing drought indicators.

Moving forward

Although the drought is largely over, California remains a dry place.  As a big dry place, some parts of California can be in drought while others are in flood (contrasting Santa Barbara and Sacramento today).  Local and regional effectiveness and adaptability are vital for water management in California.

The end of drought does not solve California’s most important water problems. Groundwater sustainability (implementing SGMA), Sacramento-San Joaquin Delta sustainability, effective ecosystem management, and fixing rural drinking water systems remain major problems.  Solving these issues involves difficult water accounting, integrated management, and finance issues at local and statewide levels.

Progress on these long-term issues is harder and requires more persistence than making progress during the urgency of a drought.  But we should reserve “drought” management for unusually dry conditions, or risk losing the public confidence that democratic governments and effective water utility management require.

Leaving the drought, California has a clearer picture of the important work that remains to be accomplished. The next drought (and flood) could be coming soon.

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

Some further reading

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

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

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

Lund, J., “After drought, California urgently needs to focus on big picture of water management,” Sacramento Bee, Op-Ed, 29 January 2017.

Posted in California Water, Drought, Uncategorized, Water Supply and Wastewater | Tagged | 21 Comments

Episode 3: “Unraveling the Knot” Water Movement in the Sacramento-San Joaquin Delta – Managing Flows

By William Fleenor, Amber Manfree, and Megan Nguyen

Delta water diversions have significant effects on flows and water quality within the Delta. Diversions can re-direct river flows and draw salt water inland from the sea, impacting water quality and the environment. Episode 3 explores how water diversion quantity affects in-Delta flow directions and quantities. This episode also looks at how in-Delta gates and barriers are used to improve in-Delta flows and water quality.

Some lessons:

  • The two biggest in-Delta diversions are the State Water Project (SWP) and the Federal Central Valley Project (CVP) near Tracy. CVP exports are fairly constant during the irrigation season and draw water from south Delta Channels, while the nearby SWP exports occur in big gulps, taking water on high tides into Clifton Court Forebay.
  • The Delta Cross Channel (DCC) near Walnut Grove helps move Sacramento River water to pumps in the south Delta. Open DCC gates direct additional flow southward into the central Delta, moving fresh water from the northern to southern Delta, supplying fresh water to the pumping plants. Large flows of Sacramento River water toward these diversion pumps reverse net flows in Old and Middle Rivers in the southern Delta.
  • Gates and flow barriers in the southern Delta keep lower-quality San Joaquin River water away from the pumps and improve south Delta water quality.
  • Heavy pumping in the southern Delta can lower water elevations in local channels so much that farmers cannot siphon water onto their fields, forcing farmers to pump water. Agricultural barriers during higher pumping months keep the water elevation high enough for siphoning in some Delta channels (Old River, Grant Line Canal and Middle River).
  • The Head of Old River Fish Barrier, on the San Joaquin River, directs migrating fish downstream rather than toward the pumps and improves export water quality by reducing flows of lower-quality San Joaquin River water to the pumps.
  • Agricultural barriers and the fish barrier along the San Joaquin River increase net negative flows in Old and Middle Rivers.

Flows change in the north Delta due to the Cross Channel and in the south Delta due to barriers and the Cross Channel. The overall effect does not change net outflow, but shifts net outflow contributions from the Sacramento River to the San Joaquin River. Unnatural water circulation from north to south entrains fish in the pumps and the southern Delta, and disrupts natural gradients between the rivers and ocean that cue fish movements.

William Fleenor is a senior researcher who specializes in hydrodynamics and hydraulic modeling at the UC Davis Center for Watershed Sciences. Amber Manfree is a postdoctoral researcher with the UC Davis Center for Watershed Sciences. Megan Nguyen is a GIS researcher at the Center for Watershed Sciences.

Further Reading

A Tale of Two Deltas: A Comparison of Transport Processes in the Predevelopment and Contemporary Delta (Jon Burau, as summarized by Maven, 2016)

Episode 1: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Introduction

Episode 2: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Tidal Forces

Episode 3: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Managing Flows

Posted in Delta | Tagged , , | 6 Comments

Episode 2: “Unraveling the Knot” Water Movement in the Sacramento-San Joaquin Delta – Tidal Forces

By William Fleenor, Amber Manfree, and Megan Nguyen

Tides are the biggest driver of Delta flows, and in Episode 2 we look at their impacts in different locations under a variety of inflow conditions.  Tides have a twice-daily cycle in the region, with a range of about six feet at Martinez.  In the first part of the animation, we remove all in-Delta controls and diversions and fix inflows at a common moderate early summer level to isolate effects of tidal forces from those of inflows, gates, and export diversions.  When the moon and sun are more aligned (full and new moon periods), tidal magnitude is greater.  Distances to the moon and sun influence tidal magnitude as do winds and barometric pressure.  Winds and barometric pressure are fixed in this animation.

The main lessons are:

  • Tidal ‘sloshing’ greatly exceeds Delta outflows. Tidal flows can be 400,000 to 600,000 cubic feet per second (cfs) at Martinez, while net outflows are often a few thousand cfs.
  • A given amount of tidal force exists at the Golden Gate, and a change in one location in the estuary has effects throughout.
  • Sacramento and Stockton Deep Water Ship channels have been deepened and straightened with dredging, which increases tidal flows up these channels and decreases tidal flows (and mixing) in other Delta channels.
  • Higher Spring tides, occurring when the sun and moon are more aligned, add volume to the Delta and by themselves can produce brief net negative flows on Old and Middle Rivers.

The second part of the animation varies Delta inflows to demonstrate how inflows and tidal forces interact, again without major Delta diversions.  We look at inflows lower than those previously shown, representing late summer, and two higher inflow levels.  Finally, we show effects of a flood pulse moving through the Yolo Bypass. The main lessons are:

  • Lower inflows increase tidally driven negative flows through Old and Middle Rivers.
  • As inflows increase, tidal influence diminishes from the upstream direction and net negative flows from the tides cease in Old and Middle Rivers.
  • Flood flows through the Yolo Bypass greatly reduce tidal influences.

Modeling produces a better understanding of natural and anthropogenic influences on Delta flows, which can help improve planning and policy-making for the Delta.

Coming next in Episode 3 is an examination of flow and salinity effects of major water diversions from the Delta.

William Fleenor is a senior researcher who specializes in hydrodynamics and hydraulic modeling at the UC Davis Center for Watershed Sciences. Amber Manfree is a postdoctoral researcher with the UC Davis Center for Watershed Sciences. Megan Nguyen is a GIS researcher at the Center for Watershed Sciences.

Further reading

A Tale of Two Deltas: A Comparison of Transport Processes in the Predevelopment and Contemporary Delta (Jon Burau, as summarized by Maven, 2016)

Episode 1: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Introduction

Episode 2: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Tidal Forces

Episode 3: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Managing Flows

Posted in Delta | Tagged , , | 6 Comments

Episode 1: “Unraveling the Knot” Water movement in the Sacramento-San Joaquin Delta

By Bill Fleenor, Amber Manfree, and Megan Nguyen

In 2010, John DeGeorge of RMA, Inc used animated model results to illustrate specific flow and water quality issues in the Delta to the State Water Board. The Center for Watershed Sciences, working with John and using RMA software, has assembled a series of narrated animations to show some major forces acting on Delta flows and water quality. The goal is to “Unravel the Knot” of California’s Delta – at least some it – in terms of flow and water quality.

In Episode 1 we start with general background of California water and the role and significance of the Delta.

The main points are:

  • The Sacramento-San Joaquin Delta watershed covers 40% of California and most of the water used in the state by humans. Rain and snowmelt feed rivers, supporting a wide variety of habitats and large populations of wildlife.
  • The Delta is a critical hub in California’s water infrastructure, conveying fresh water from the wetter northern part of the state to farms and cities in the drier south. Water deliveries supporting intensive agriculture and supplying urban areas have spurred enormous economic growth. This has come with significant environmental tradeoffs.
  • The Delta is largely tidally influenced, and potential for rapid large-scale flooding of sunken island interiors, combined with sea level rise impacts, threaten its use as a conduit for water delivery, and raise the possibility of sudden, sweeping environmental changes.
  • Understanding how water moves in the Delta can help in planning for the future. This video series examines each component of water movement separately, and explains how shifts in water management, levee failure, and sea level rise might change the Delta and California’s water supply in the years ahead.

William Fleenor is a senior researcher who specializes in hydrodynamics and hydraulic modeling at the UC Davis Center for Watershed Sciences. Amber Manfree is a postdoctoral researcher with the UC Davis Center for Watershed Sciences. Megan Nguyen is a GIS researcher at the Center for Watershed Sciences.

Further Reading

A Tale of Two Deltas: A Comparison of Transport Processes in the Predevelopment and Contemporary Delta (Jon Burau, as summarized by Maven, 2016)

Episode 1: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Introduction

Episode 2: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Tidal Forces

Episode 3: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Managing Flows

Posted in Delta | Tagged , , | 9 Comments

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 Drought, Uncategorized | Tagged | 6 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 Drought, Uncategorized | Tagged | 12 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 Drought, Uncategorized | Tagged | 7 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:


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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.

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