Water conservation for the birds

Butte Sink Wildlife Management Area. Photo by U.S. Fish and Wildlife Service

Sacramento Valley’s Butte Sink Wildlife Management Area. Source: U.S. Fish and Wildlife Service

By Jay Lund

People who save water like to know their conserving is doing some good, such as sustaining economic growth, building municipal reserves for longer droughts or supporting the environment.

But many urban residents are concerned their water savings will go to uses they value less — such as supplying more wasteful customers, new urban development or agriculture — rather than meeting the needs of fish, waterbirds and other wildlife, which they value more. In fact, most household water conservation does free up water for other local users or eases State Water Project and Central Valley Project supplies for other thirsty cities or farms, rather than go directly to environmental protection.

For households interested in conserving water for environmental purposes, a bargain might be struck. The table below lays out how people might be motivated to use less water knowing that much of their savings would be dedicated to a favored environmental cause, such as supporting wildlife refuges.                           

Water Conservation for the Birds — Who Does What?


Source: Jay Lund/UC Davis

Wildlife refuges seem the most suitable place to begin such voluntary environmental water transactions. Water management for refuges is generally more structured and precise than for fish and have more developed assessments of how their water use affects wildlife. Refuges also are better tied into the water supply system, making it easier to move water to wetlands most in need.

Urban water savings would make major, measurable improvements at refuges, where a little goes a long way.

Sacramento National Wildlife Refuge. Photo by U.S. Fish and Wildlife Service

Sacramento National Wildlife Refuge. Source: U.S. Fish and Wildlife Service

Central Valley refuges use about 600,000 acre-feet a year for waterbirds and other critters, compared with a statewide net urban water use of about 6.6 million acre-feet a year — about half for landscape irrigation. So a 10 percent savings in urban water use, or a 20 percent reduction in landscape watering, could roughly double water for wildlife refuges.

Such a program would better define and publicize the ties between local water use and the health of California’s ecosystems. Once urban water customers see their conservation efforts making a difference, they will likely be motivated to make further savings.

If successful for wildlife refuges, it could be expanded to fish and other environmental purposes, creating wildlife and recreational assets and empowering environmental water management.  We could make water conservation for the birds, and for the fish.

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

Further reading

Lund J and Moyle P. “Water giveaways during a drought invite conflict“. CaliforniaWaterBlog. March 23, 2015

Lund J. “New environmentalism needed for California water“. CaliforniaWaterBlog. Dec. 9, 2014

Lund J, et al. “Why give away fish flows for free during a drought?” CaliforniaWaterBlog. Feb. 11, 2014

Hanak, E., et al. “Managing California’s Water: From Conflict to Reconciliation“, Public Policy Institute of California, San Francisco, CA, 500 pp., February 2011.

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Time-lapse river videos expose nature in the raw

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Video surveillance helps tell the story of rivers in the Sierra Nevada. This frame shows the confluence of the Tuolumne and Clavey river downstream of Yosemite National Park during a storm on Feb. 7, 2015. Source: UC Davis Center for Watershed Sciences

By Ryan Peek


A group of science teachers from senior and junior high schools participating in the Center for Watershed Science’s Tuolumne River Institute hike along the wizened North Fork of the Tuolumne River, which was reduced to puddles in the fourth summer of severe drought. Photo by Ryan Peek, July 2015

Thanks to its Mediterranean climate, California swings from one extreme to another — severe drought, raging wildfires, big floods. These forces often interact and amplify, as we saw all too well this past summer in the scorching of hundreds of thousands of extremely dry forested acres, with the loss of homes and lives. Big floods could be just around the corner, if predictions of a “Godzilla El Niño” hold true.

Researchers with the UC Davis Center for Watershed Sciences watch these dramas play out in several rivers of the Sierra Nevada. As part of a long-term river monitoring project, we track changes in streamflow, temperature and structure of river channels. We also regularly collect data on fish diversity, native frog breeding and the diversity and abundance of aquatic invertebrate.

The data are useful for linking physical and ecological processes, but they don’t always tell the whole story.

Game Cameras

Researchers mount game surveillance cameras on riverside trees to take hourly pictures of Sierra rivers. Source: UC Davis

A few years ago we began to get a fuller picture after installing a number of small time-lapse cameras at key locations within our monitoring sites. Typically used by hunters for game surveillance, these rugged weatherproof devices are programmed to take a picture every hour.

We compile the photos into time-lapse videos and can overlay river data collected at the same location.

Hydrograph curves showing changes in streamflow take on new meaning when matched with corresponding videos, as shown below. We can see what a daily change of, say, 600 cubic feet per second actually looks like in a river.

Note during winter storms how much muddier the river turns in 2015, compared with 2012. The 2013 Rim fire accounts for the difference. This was the largest Sierra fire in more than a century of recordkeeping. It burned 257,314 acres (400 square miles), much of it within the Tuolumne River watershed. With rain and higher flows, sediment from hill slopes can be mobilized and flushed into the river. The loss of trees from the fire amplified this effect, creating less stable soil in the steep river canyon. 

Hydrographs and videos of Tuolumne-Clavey confluence

1. January – July 2012


2012 hourly discharge on Tuolumne River at Wards Ferry in cubic feet per second (cfs). Source: U.S. Geological Society, gauge 11285500

2. January – July 2015


2015 hourly discharge on Tuolumne River at Wards Ferry in cubic feet per second (cfs). Source: U.S. Geological Society, gauge 11285500

Documenting changes in river systems and comparing them over time is key to understanding the ecological impacts of fires, floods and droughts.

Tuolumne_Watershed_v4Fire and floods beget erosion and mudslides, clouding waterways with high loads of sediment. High stream flows help “reset” river ecosystems by scouring vegetation, moving sediment and forming new habitat.

Many native California organisms depend on such diverse and dynamic river processes. Dynamism promotes biodiversity.

Videos of the Tuolumne-Clavey confluence are particularly instructive. They capture events before and after the Rim fire. The blaze felled the tree that held our camera, but the device remained attached to the trunk and continued to take pictures and ground level, as shown in this video narrated by Watershed Sciences researcher Eric Holmes:


A thick mantle of silt cover a cobble bar in the Tuolumne River following winter storm in 2015. The 2013 Rim fire cooked the soil in parts of the watershed, creating a high potential for erosion and runoff. Photo by Ryan Peak, May 2015.

The drought has minimized the post-fire erosion in the Tuolumne River canyon. Still, with only moderate rain, you see significant increases in turbidity and sedimentation. Visiting the monitoring site this past May, we found a foot or more of silt along the banks.

Heavy sedimentation can have major impacts on native aquatic species such as the foothill yellow-legged frog. The frogs attach their egg masses to rocky substrates in sheltered slow-moving waters of rivers and creeks. The females lay only a single egg cluster a year, so the loss of these breeding grounds to heavy sedimentation can significantly diminish reproductive success. 

Foothill yellow-legged frog. Photo by Ryan Peek

A rare foothill yellow-legged frog finds part of its breeding habitat on the Tuolumne River smothered in silt. Photo by Ryan Peek, May 2015

Similarly, the eggs of salmon and trout require constant flow through their gravel nests to supply enough oxygen for their development. Sedimentation can also smother bottom-dwelling macroinvertebrates, an important food source for many species.

At the same time, the buildup of sediment can provide new areas for riparian vegetation to take hold.

Ironically, the banks of the Tuolumne and Clavey rivers are noticeably lusher these days because of the Rim fire and drought. The post-fire sedimentation and lack of high flows to flush the drought-stricken rivers have allowed riparian vegetation to gain traction.

Time-lapse videos show changes in riparian vegetation on the Clavey River before (2012) during (2013) and after (2015) the Rim fire. Heavy sedimentation following the fire allowed plants and trees to take root. Source: UC Davis Center for Watershed Sciences

Time-lapse videos show changes in riparian vegetation on the Clavey River before (2012) during (2013) and after (2015) the Rim fire. Heavy sedimentation following the fire allowed plants and trees to take root. Source: UC Davis Center for Watershed Sciences

Time-lapse videos help us understand the ebb and flow of rivers we study. They make it apparent how dynamic these systems can be. They also show the power and importance of fires and floods in creating, maintaining and changing habitat for fish, amphibians and other aquatic life.

Ryan Peek is a doctoral student in ecology at UC Davis.

Further resources

Animated map of Rim fire (Video, ~1 min.). Open Data City. September 2013

Santos N. 2014. “Remote Sensing, Event-Based Monitoring and Change Detection Using Off-the-Shelf Hardware” (Video, ~13 mins). UC Davis Center for Watershed Sciences. April 30, 2014

Time-lapse videos of Sierra Nevada rivers (Videos). UC Davis Center for Watershed Sciences

Data on stream temperatures and stages. UC Davis Center for Watershed Sciences

Boxall B. Rim fire’s effects likely to last for decades to come“. Los Angeles Times. Sept. 23, 2013

Jeffres C, Peek R, Ogaz M. “Journey to the bottom of the Rim fire“. California WaterBlog. Sept. 26, 2013

Park H, Cave D, Andrews W, Canepari Z. “After years of drought, wildfires rage in California“. New York Times. July 15, 2015

Swain D. “California fire season explodes“. California Weather Blog. Aug. 4, 2015

Viers J and Santos N. 2014. “Hydrolapse Videography: A Coupled Hydroinformatic Stack for Improved Visual Assessment of River Dynamics“. 11th International Conference on Hydroinformatics. HIC 2014. New York City.



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

The south fork of Lake Oroville, California's second largest reservoir, in September 2014. Photo by Kelly M. Grow/California Department of Water Resources.

The south fork of Lake Oroville, California’s second largest reservoir, in September 2014. Photo by Kelly M. Grow/California Department of Water Resources

By Jay Lund

California’s ongoing drought will continue to break records and grab headlines, but it is unlikely to be especially rare from a water policy and management perspective.

Estimates of the current drought’s rarity range from once in 15 years to once in 1,200 years (Griffin and Anchukaitis 2014), depending on the region and indicators used (precipitation, stream runoff, soil moisture or snowpack). In the Middle Ages, large parts of California had droughts far worse than this one, some lasting more than a century (Stine 1994). The probability of California experiencing a once in 1,200-year drought during a short human lifetime is extremely low.

The chance that this dry period is a “new normal” is probably small. Many parts of Australia are paying for expensive desalination plants built when a severe drought was misinterpreted as a new normal. If this drought is as unusual as once in 1,200 years, then why pay heed beyond just getting through it? We are unlikely to see the likes of it again.

The obsession over El Niño and the California drought masks the reality that the atmospheric condition is poorly correlated with stream flows in Northern California, where 75 percent of the state’s water supply originates.

East Coast news media should keep this perspective: Every summer California has a drought far drier and longer than the eastern U.S. has ever seen. This explains California’s extensive water and irrigation infrastructure (and why people move to California).

Distressed vineyard in Coachella Valley on July 10th 2014.

Drought-stressed vineyard in Coachella Valley in July 2014. Photo by Kelly M. Grow/California Department of Water Resources

The uniqueness of an individual drought is fascinating. Each drought is unique in area, persistence, dryness, temperature, internal pattern and how it ends. California’s current drought is unusually severe, and certainly the worst since 1988-1992. Groundwater in the Tulare basin is probably lower than at any time in human history. This drought also has been unusually warm, leading to it having the lowest snowpack in 500 years and driest soil in 1,200 years. In precipitation and flows on major rivers, the 2012-2015 drought so far ranks between the third and eighth driest years on record.

By focusing on unique aspects of a drought, any drought can become an incredibly rare event. Becoming engrossed in the superlatives, however, can distract from the business of managing water shortages and preparing longer-term solutions.

What’s more relevant for water policy and management is the banality of drought. We should expect to see droughts in California of severity similar to the current drought about once or twice in a generation. Given climate change and the growth in expectations and values for diverse water uses, it seems reasonable to expect such droughts a bit more frequently than in the past. The warmer temperatures in this drought seem likely to become normal for future droughts, with disproportionate effects on ecosystems and small streams.

Lake Oroville's Bidwell Marina in September 2014. Photo by Kelly M. Grow/California Department of Water Resources

Lake Oroville’s Bidwell Marina in September 2014. Photo by Kelly M. Grow/California Department of Water Resources

Agencies, cities, bankers, insurers, farmers and residents should prepare for greater regularity of droughts as harsh as the current one. Severe drought in California should be reclassified from a rare “act of God” to something more like a business cycle swing that recurs several times in a lifetime or career.

California is managing pretty well under the current drought in most areas (Howitt et al. 2015; Hanak et al, 2015) and can survive much more severe and prolonged droughts, if managed well (Harou et al, 2010).

It is more important to focus on managing the dry event and preparing for future ones than understanding the fascinating intricacies of drought origins and statistics. But we probably will continue to obsess about drought statistics and El Niño anyway.

Further reading

Belmecheri S, Babst F, Wahl ER, Stahle DW and Trouet V. (2015). “Multi-century evaluation of Sierra Nevada snowpack.” Nature Climate Change. doi.org/10.1038/nclimate2809

Cayan D and Mount J. “Don’t count on El Niño to end the drought.” Viewpoints/The PPIC Blog. July 9, 2015

Griffin D and Anchukaitis KJ. (2014), “How unusual is the 2012–2014 California drought?Geophys. Res. Lett., 41, 9017–9023, doi:10.1002/2014GL062433

Hanak E, Mount J, Chappelle C, Lund J, Medellín-Azuara J, Moyle P and Seavy N. What If California’s Drought Continues? 20 pp. PPIC Water Policy Center, San Francisco, CA, August 2015

Harou JJ, Medellin-Azuara J, Zhu T, Tanaka SK, Lund J, Stine S, Olivares MA and Jenkins MA. (2010).  “Economic consequences of optimized water management for a prolonged, severe drought in California.” Water Resources Research, doi:10.1029/2008WR007681, Vol. 46

Howitt R, MacEwan J, Medellín-Azuara J, Lund J. “Drought bites harder, but agriculture remains robustCaliforniaWaterBlog. Aug. 18, 2015

Howitt R, Medellín-Azuara J, MacEwan D, Lund J and Sumner D. (2015). “Economic Analysis of the 2015 Drought for California Agriculture.” Center for Watershed Sciences, UC Davis. 16 pp. August 2015

Lund J. (2014). “Could California weather a mega-drought?CaliforniaWaterBlog. June 29, 2014

Lund J and Mount J. “Will California’s drought extend into 2015?California WaterBlog. June 15, 2014

Schonher T and Nicholson SE. (1989). “The Relationship between California Rainfall and ENSO Events.” Journal of Climate, Vol. 2, Nov. pp. 1258-1269

Stine S. (1994). “Extreme and persistent drought in California and Patagonia during medieval time“. Nature, 369, 546–549, doi:10.1038/369546a0

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How research programs stack up — a photo essay

By Jay Lund

Riding into work the other day, I was thinking how our understanding of hard problems requires understanding a lot of pieces and how those pieces fit together – sort of like how a pile of bricks gets transformed into a habitable structure.

If every research study is a brick in our understanding, how would research programs stack up?

Most research programs

1. Most research programs. 


2. Some of the better agency research programs.

Lightweight bricks stack easier

3. Lightweight studies stack easier.

Many studies are colorful, but not strong

4. Many studies are colorful, but not strong.


5. A common tenure package.


6. Building from different brick types and shapes is difficult, but often necessary.

7. Often research must move forward creatively

7. Often research must move forward creatively. 

8. What we wanted

8. What we wanted.

Often the best we can do

9. Often the best we can do.

Photo credits: (1) Jeff Stvan/Flickr Commons, (2) Simon Bratt/Depositphotos, (3) Jack Two/Flickr Commons, (4) Derek Bruff/Flickr Commons, (5) Glyn Lewis/Depositphotos, (6) Tim Abbott/Flickr Commons, (7) Buzzhunt, (8) Google Maps, (9) Dave Herholz/Flickr Commons


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For a change in Delta perspective, move a few feet


The Sacramento-San Joaquin Delta is a study in contrasts. It’s a lush oasis framed by parched terrain and a hodgepodge of native and non-native plants and fish. Here, floating mats of invasive water hyacinth gather against stands of native tule. Photo by Jay Lund

By Jay Lund

Each year my family takes a week’s vacation in the Sacramento-San Joaquin Delta on our old sailboat. We often follow some Delta veterans who show us new places.

As an engineering professor working on California’s water problems, I research the Delta mainly as a water supply hub and a flood-prone landscape. Sailing the Delta affords me some wonderfully different perspectives. Here are some of them:

  • The Delta is a big place. Leisurely sailboat cruises from the western to the southern and northern ends of the Delta usually take a few days, with many miles of winding channels. Traversing the Delta flat out is a full day’s sail.DeltaMap
  • The Delta is a wet place in a dry region. Summer boating in the Delta is a study in contrasts. You’re in a watery place — surrounded by levees, sloughs, marsh, marinas, irrigated farms — and yet the backdrop is vividly waterless, with parched brown hills on the horizon. It’s a reminder that the Delta is an oasis in a mostly arid state. 
  • The Delta is many different places. One of the Delta’s best recreational (and, potentially, ecological) assets is its variety. For example:
    • The north Delta features clearer water and larger wetlands, secluded anchorages (I’m not saying where) and colorful river towns (such as Rio Vista, Walnut Grove and Isleton). 
    • Waters on the west are windier, saltier and muddier. (Marinas there struggle more with mud because of mixing sea salt.)
    • The flooded islands of the central and north Delta are very different from one another, from the deep anchorage of Mildred Island (now an atoll), to the fishing grounds of Franks Tract, the many small tracts (such as Rhode Island, Big Break and Little Mandeville Island), and the more native-fish friendly Sherman Lake and Liberty Island.
    • Windsurfers and a kiteboarder take advantage of a gusty morning at Sherman Island County Park on September 18, 2014.

      Windsurfer and kiteboarder take advantage of a gusty morning off  Sherman Island. Photo by Florence Lo/California Department of Water Resources.

      The south Delta has slower moving waters, with more water hyacinth clogging channels, huge agricultural tracts and destinations near Stockton.

  • The Delta has great recreation for everyone. Recreationally and socially, the Delta is one of California’s most diverse playgrounds. It’s rich in fishing, boating, summer camping, history and scenic tourism. Given the prevailing summer winds, it is pleasant to sail east into the Delta, but hard to sail west out of the region. 
  • The Delta has a wonderful history of change. Every year the Delta is a little different. In just a generation, the Delta has gained two new “lakes” as a result of levee failures and subsequent land abandonment on Mildred and Liberty islands. River channels are always changing, but many features endure. It is astonishing to see the remnants of deep river channels cut off decades ago. 
  • Delta waterways are littered with failed solutions. A common example is the thousands of dead sticks installed along channels to combat erosion. Intuitively attractive and well-intended solutions sometimes don’t work – but someone did pay for them.
  • Invasive plants are taking over many places. Floating mats of water hyacinth are widespread in the south Delta and encroach some channels in the central Delta. Boaters can usually steer around the hyacinth. However, Brazilian waterweed, a home aquarium escapee, lurks below the surface in shallower water and can clog engine intakes.
  • The Delta ecosystem is now dominated by non-native species, but the natives are still there. The spread of invasive plants parallels the spread and dominance of non-native fishes. In most of the Delta more than 90 percent of the fish are non-native — but the fishing is good.

Jay Lund at the helm of his sailboat in the Delta. Photo by Jean Lund

  • Move a few feet, and you often see a different Delta. From the water, the Delta is a lush recreational paradise. From the top of many levees, the Delta appears dangerously below sea level, thinly protected by narrow earthen levees. From land, much of the Delta looks economically vibrant with rows of crops and fruit trees.

All these viewpoints are so close together, yet so far apart.

Jay Lund, a lifelong sailor, is a professor of civil and environment engineering and director of Center for Watershed Sciences at UC Davis.

Further reading

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

Lund J, Hanak E, Fleenor W, Howitt R, Mount JF, Moyle PB. 2007. Envisioning Futures for the Sacramento-San Joaquin Delta. Public Policy Institute of California, San Francisco, CA

Lund J. 2011. “Sea level rise and Delta subsidence—the demise of subsided Delta islands”. CaliforniaWaterBlog.com. March 9, 2011

Moyle PB. 2013. “Ten realities for managing the Delta. California WaterBlog. Feb. 26, 2013

Whipple AA, Grossinger RM, Rankin D, Stanford B, Askevold RA . 2012. Sacramento-San Joaquin Delta Historical Ecology Investigation: Exploring Pattern and Process. Publication #672. San Francisco Estuary Institute-Aquatic Science Center, Richmond, CA

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Delta smelt’s unsung cousin seems verging on extinction, too


The longfin smelt, so-named for its long pectoral fins, lives in the open water of San Francisco Estuary. Source: U.S. Bureau of Reclamation

By James Hobbs and Peter Moyle
Another native fish of the Sacramento-San Joaquin Delta appears to be rivaling the cliffhanger status of the delta smelt.

Relative to its historical abundance, the lesser-known longfin smelt has experienced an even bigger decline than delta smelt — and may be in bigger trouble — according to trawl surveys of Delta fishes.

In the past two years, catches of adult longfins have been close to zero, and a recent larval survey found alarmingly few of the smelt. The dramatic downturn is likely a result of the drought, as with the tinier delta smelt.

Lacks federal protection

Unlike its headline-grabbing relative, the longfin is not listed under the federal Endangered Species Act.

In 2012 the U.S. Fish and Wildlife Service determined that the Delta population of longfin smelt deserved protection, but designated the fish only as a candidate for listing. The less powerful California Endangered Species Act lists the species as threatened with extinction. Presumably, the federal protections for the delta smelt have benefited the longfin and other native fishes because it is the species most sensitive to changes in the Delta’s waterways.

The longfin and delta smelt were once common, thriving inhabitants of the Delta and elsewhere in the open waters of San Francisco Estuary. The longfin live two to three years longer than the delta smelt and grow twice as big – up to 5 inches long – big enough to have been an important part of the San Francisco Bay commercial smelt fishery in the 19th century.


Longfin smelt grow up to 5 inches, about twice the length of nature delta smelt. Photo by Randall Baxter/California Department of Fish and Wildlife

The longfin population was the most abundant fish in the upper estuary. The population has gone through several boom and bust periods (Figure 1).

The initial slump, in the 1980s, was at least partially the result of the invasion of the overbite clam, which has robbed pelagic fish of food. Starting in 2002, the population nosedived, following the trajectory of delta smelt and other species — a trend known as the Pelagic Organism Decline

Sampling programs all show population collapsing

Before 1980, the state’s Fall Midwater Trawl survey alone would catch thousands of individuals in a four-month season (September-December). Since 2002, only 10 – 100 fish have been captured per season.

A similar pattern is shown in the San Francisco Bay Study, a monthly fish survey that uses midwater and bottom otter trawls to sample from South San Francisco Bay to the North Delta. Together, the state surveys show a dramatic decline of longfin smelt throughout the estuary (Figure 2).

Likewise, our monthly sampling in Suisun Marsh, which UC Davis began in 1979, has shown a long-term decline of the smelt (Figure 3).

siderTom Cannon, an estuarine fisheries ecologist and biostatistician, was perhaps the first to sound the alarm over the estuary population of longfin smelt, in a recent California Fisheries Blog headlined, “They’re Gone.” 

Are they on the verge of extinction? The answer is not as clear as it seems to be for delta smelt, in part because so much less is known about longfin.

Recent UC Davis surveys have found longfin smelt in areas not previously monitored — Alviso Marsh in the lower South Bay, Napa-Sonoma Marsh, Petaluma River and the Cache-Lindsey Complex of the North Delta — raising the question of whether the smelt’s distribution has changed.

While the species clearly is in severe decline, it is possible that sampling programs are missing significant segments of the population. In summer and fall, substantial numbers inhabit coastal waters — outside areas surveyed.

However, all sampling programs within the estuary show longfin of all ages collapsing in the past few years,  suggesting an estuary-wide decline.

Drought impacts

The aggressive invasion of the overbite clam in San Francisco Estuary is blamed as one of the causes of the decline of delta and longfin smelt in recent years. Photo by Cynthia Brown/U.S. Geological Survey

The aggressive invasion of the overbite clam in San Francisco Estuary is blamed as one of the causes of the decline of delta and longfin smelt in recent years. Photo by Cynthia Brown/U.S. Geological Survey

The abundance of longfin smelt, particularly young-of-year, increases with the amount of freshwater flowing through the estuary (Figure 4). The fish also seems to have a low tolerance for warmer waters, with adults rarely found in water warmer than 64 degrees (18 degrees C) and young-of-year above 73 degrees (22 degress C) [Figure 5].

Warmer temperatures and less freshwater flow in the Delta are associated with drought, so if the drought continues, longfin smelt are likely to be extirpated from the estuary. Even if the drought ends, smelt numbers may be so low that recovery will be difficult and slow.

Recolonization from more northern populations is possible but highly uncertain, reflecting a need for more research on the basic biology of the species. We just hope the smelt will still be around to study.

James Hobbs is a research scientist and Peter Moyle if a professor of fish biology, both with the UC Davis Department of Wildlife, Fish and Conservation Biology. This article was originally posted on Aug. 31, 2015 and revised Sept. 1 with additional information and sources.

Further reading

Hobbs, J. A., C. Parker, J. Cook and M. Bisson. 2015. Technical Report: The distribution and abundance of larval and adult longfin smelt in the San Francisco Bay tributaries Year 1: Pilot Study. DOI: 10.13140/RG.2.1.3185.5843

Hobbs, J.A., L. L. Lewis, N. Ikemiyagi, T. Sommer and R. Baxter. 2010. “The use of otolith strontium isotopes (87Sr/86Sr) to identify nursery habitat for a threatened estuarine fish.” Environmental Biology of Fishes. 89:557-569. DOI 10.1007/s10641-010-9762-3

Merz, J.E., P.S. Bergman, J. F. Melgo and S. Hamilton. 2013. Longfin smelt: spatial dynamics and ontogeny in the San Francisco Estuary, California. California Fish and Game 99(3):122-148

Rosenfield, J. A. and R. Baxter. 2007. Population dynamics and distribution patterns of longfin smelt in the San Francisco Estuary. Transactions of the American Fisheries Society 136:1577-1592


Figure 1.  Fall Midwater Trawl Survey abundance indices for most common Delta fishes, 1967 – 2014. (Axes scaled to abundance of longfin smelt, with breaks in y-axis for less abundant species) Source: California Department of Fish and Wildlife


The longfin and delta smelt were once abundant in the Delta and elsewhere in the open waters of San Francisco Estuary. The longfin live two to three years longer than the delta smelt and grow twice as big – up to 5 inches long – big enough to have been an important part of the San Francisco Bay commercial fishery in the 19th century.

Figure 2.  Abundance indices (standardized) for longfin smelt, 1980 – 2014. Source: California Department of Fish and Wildlife 


Figure 3. Catch-per-minute otter trawling Suisun Marsh, 1980 – 2014. Source: UC Davis



Longfin smelt abundance in the Fall Midwater Trawl (log transformed) plotted against freshwater outflow (log transformed). Regressions lines for the 1967-1987 pre-Corbula years, 1988-2000 Corbula invasion period, and from 2002-2014 “modern-climate regime”. Corbula is an invasive clam that has reduced the food supply for longfin smelt and other pelagic species.

Figure 4.  Longfin smelt abundance in Fall Midwater Trawl plotted against Delta freshwater outflow (log transformed). Regression lines for 1967 – 1987 (pre-overbite clam invasion); 1988 – 2000 (during invasion); and 2002 – 2014 (post-invasion). The invasive overbite clam has robbed food from longfin smelt and other pelagic species. Source: California Department of Fish and Wildlife

Smoothed presence-absence data from the San Francisco Bay Study (Otter trawl + midwater trawl) for Age-0, Age-1 and Age-2 longfin smelt occurrence with water temperature. (data 1980-2013)

Figure 5.  Smoothed presence-absence data of longfin smelt — Age 0, Age 1 and Age 2 –with water temperature, 1980 – 2013. Source: San Francisco Bay Study (otter and midwater trawls) 



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Guidance for putting new groundwater law on the ground


Groundwater fills irrigation ditch on a Kern County cotton field in the 2015 drought. Photo by Chris Austin/Maven’s Notebook

By Thomas Harter, Vicki Kretsinger Grabert and Tim Parker

A group that helps shape California groundwater policy has proposed several ideas for state consideration in implementing the 2014 Sustainable Groundwater Management Act (SGMA).

The Contemporary Groundwater Issues Council of the Groundwater Association of California – comprised of various agency executives and influential water researchers and consultants – weighed in on three major issues the California Department of Water Resources (DWR) will face in the next 18 months as it drafts the law’s regulations and guidelines:

  • Criteria for DWR evaluation of Groundwater Sustainability Plans (GSPs)
  • Best Management Practices (BMPs) for sustainable groundwater management
  • Tools and technologies that DWR needs to provide to local Groundwater Sustainability Agencies (GSAs) for effective implementation of the law.

The council developed the recommendations earlier this summer after inviting officials at DWR and the State Water Resources Control Board to present their ideas and plans for the law’s implementationScreen Shot 2015-08-26 at 10.33.22 PM.png

1. Evaluating sustainability plans

By mid-2016, DWR will have set regulations on the evaluation and implementation of GSPs (Figure 1 below). The council addressed several topics relevant to drafting those rules, mainly:

  • How to assess: (1) appropriateness of a GSP, (2) metrics for measuring success, (3) integrating the required 50-year planning horizon and (4) public outreach and stakeholder engagement in the GSP process
  • How to address cross-basin boundary challenges

Council members’ concerns included:

  • Making regulations sufficiently flexible for a highly variable and somewhat subjective process while being firm on attaining sustainability goals
  • Some regions missing the mandatory deadline for completion of GSPs because they were politically challenged and slow to form GSAs.
  • DWR’s ability to provide GSAs the technical assistance needed to develop acceptable plans
  • Lack of adequate data in some basins to prepare adequate GSPs
  • Timeliness of DWR’s GSP reviews
  • Constitutional restrictions imposed by California’s Proposition 218 – a 1996 voter-approved initiative – may impede GSA financing

Evaluating GSPsScreen Shot 2015-08-26 at 10.35.17 PM.png

2. Best Management Practices for achieving sustainability

The law requires DWR to publish Best Management Practices (BMPs) by Dec. 31, 2016. Issues for consideration include:

  • Infrastructure approaches to increase recharge and decrease groundwater demand
  • Assessment of BMPs’ effectiveness
  • Data needs
  • Technical/financial/regulatory support to advance implementation of programs and practices
  • Outreach and education

Concerns include:

  • How regulations would address data confidentiality
  • Availability of technical assistance to facilitate effective implementation of BMPs
  • Standardizing data collection, monitoring and modeling/assessment to ensure attainment of basin objectives without being overly prescriptive
  • Quality assurance and control (QA/QC) in data collection, reporting and assessment
  • Availability and adequacy of staff and expertise

Best Management PracticesScreen Shot 2015-08-26 at 10.41.39 PM.png

3. Tools and technologies for effective implementation

The success of the new groundwater law depends in part on providing local agencies useful tools and technologies for developing and implementing the GSPs.

For economies of scale it may be more advantageous that the state provide the big data tools. These would include INSAR (Interferometric Synthetic Aperture Radar) to evaluate the effects of groundwater extraction on land subsidence; SEBAL (Surface Energy Balance Algorithm for Land) for mapping evapotranspiration; and other remote sensing and advanced monitoring techniques. The state also has basin-wide models that can be improved and used for water budgeting and to verify sub-basin and other area-specific models.

The council raised some of the same concerns as in topic 1 and 2 – cost, balance of flexibility vs. effectiveness, need for data QA/QC and lack of data – plus one more: Losing coherency and transparency in data collection by dispersing the effort among too many agencies. The concern is over local agencies’ willingness to share data and conform to electronic formats compatible with statewide databases.

Tools and TechnologiesScreen Shot 2015-08-26 at 10.37.43 PM.png

Thomas Harter is a groundwater specialist with the UC Davis Center for Watershed Sciences. Vicki Kretsinger Grabert is president of Luhdorff & Scalmanini Consulting Engineers in Woodland, Calif., and Tim Parker is president of Parker Groundwater in Sacramento. Harter and Parker are on the board of directors of the Groundwater Resources Association of California and Grabert is a former board member.

Figure 1: Summary of SGMA regarding DWR regulations for GSPs
Screen Shot 2015-08-26 at 10.01.29 PM.png

Figures 2: Excerpts from SGMA on best management practices and assessment of water available for groundwater replenishmentScreen Shot 2015-08-26 at 9.53.32 PM.png

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Drought bites harder, but agriculture remains robust

50-Line-between-the-planted-and-unplanted copy

Irrigation ditch divides a vineyard and unplanted field near the Fresno County town of Huron, on the west side of the San Joaquin Valley. Photo by Chris Austin of Maven’s Notebook

Spanish version

By Richard Howitt, Duncan MacEwan, Josué Medellín-Azuara and Jay Lund

Today we release our second annual report estimating the economic impacts from prolonged drought.

More than anything, the results of our 16-page analysis of the current growing season speak to agriculture’s remarkable resilience to multiyear surface water shortages. They also show that the industry’s ability to continue growing in revenue and jobs is coming at increasingly higher costs.

Overall, California’s $46 billion-a-year agricultural output remains robust in this fourth year of severe drought, mostly because of the state’s vast reserves of groundwater. Drawing on these reserves will replace an estimated 70 percent of the surface water shortage this year, compared with a 75 percent offset in 2014.


Source: Economic Analysis of the 2015 Drought on California Agriculture, executive summary

Continued strong global demand has driven high prices for many of California-grown fruits, nuts and vegetables also has helped sustain the farm economy along with water transfers and shifts in growing locations.

Our survey of more than 70 irrigation districts earlier this summer and spring indicates an increase in water transfer activity over the previous year. The average water transfer price is more than $650 an acre-foot, compared with $500 an acre-foot in 2014. Water transfers and shifts in crop contracts can significantly temper the economic impacts of drought throughout the Central Valley, particularly on perennial fruit and nut orchards and grape vines and higher-value vegetables.

These factors are having their largest effect in the Sacramento Valley. Strong prices have shifted contracts for tomatoes grown for canning north, from the San Joaquin Valley to areas in the Sacramento Valley with better access to water. In addition, farmers statewide have been moving from field crops to higher-value almonds and walnuts, with more than 200,000 acres of new orchards planted since 2010.

Taken together, these adjustments blunt much of the economic blow of drought to agricultural communities and food consumers.

That said, several small rural communities continue to suffer from high unemployment and drying up of domestic wells because of the drought, particularly in the Tulare Basin.

Further, the heavy reliance on groundwater comes at ever-increasing energy costs as farmers pump deeper and drill more wells. Some of the heavy pumping is in basins already in severe overdraft, inviting further land subsidence and water quality problems, and diminishing reserves needed for future droughts.

If the drought persists beyond 2015 at its current intensity, California’s agricultural production and employment will face further reductions.

As with our 2014 analysis, this year’s study was prepared at the request of the California Department of Food and Agriculture using computer models and the latest estimates of surface water availability from state and federal water projects and local water districts.

Our key findings:

  • The total impact of the 2015 drought to all economic sectors is an estimated $2.74 billion, compared with $2.2 billion in 2014. About $1.84 billion of that are drought-related costs to the agriculture industry. (The state’s farmers and ranchers currently generate more than $46 billion annually in gross revenues, a small fraction of California’s $1.9 trillion-a-year economy.)
  • The loss of about 10,100 seasonal jobs directly related to farm production, compared with the researchers’ 2014 drought estimate of 7,500 jobs. When considering the spillover effects of the farm losses on all other economic sectors, the employment impact of the 2015 drought more than doubles to 21,000 lost jobs.
  • Surface water shortages will reach nearly 8.7 million acre-feet, which will be mostly offset by increased groundwater pumping of 6 million acre-feet.
  • Net water shortages of 2.7 million acre-feet will cause roughly 542,000 acres to be idled – 114,000 more acres than the researchers’ 2014 drought estimate. Most idled land is in the Tulare Basin.
  • The effects of continued drought through 2017 (assuming continued 2014 water supplies) will likely be 6 percent worse than in 2015, with the net water shortage increasing to 2.9 million acre-feet a year. Gradual decline in groundwater pumping capacity and water elevations will add to the incremental costs of a prolonged drought.

The state’s new groundwater law requiring local agencies to attain sustainable yields could eventually reverse the depletion of underground reserves. The transition will cause some increased fallowing of cropland or longer crop rotations but will help preserve California’s ability to support more profitable permanent and vegetable crops during drought.

Overall, our results show California agriculture faring much better this year than many had predicted.

In a recent commentary for the New York Times, journalist Charles Fishman observed that, “amid all the nervous news, the most important California drought story is the one we aren’t noticing. California is weathering the drought with remarkable resilience.”

We agree.

Richard HowittJosué Medellín-Azuara and Jay Lund are researchers with the UC Davis Center for Watershed Sciences. Duncan MacEwan is with ERA Economics of Davis, Calif. They co-authored the report, “Economic Analysis of the 2015 Drought for California Agriculture,” which was released Aug. 18, 2015.

Downloads of 2015 report:

Further reading

Fishman C. (2015). “How California is Winning the Drought.” New York Times. Aug. 14, 2015

Howitt R, Medellín-Azuara J, MacEwan D, Lund J and Sumner D. (2015) “Economic Analysis of the 2015 Drought for California Agriculture.” Center for Watershed Sciences, UC Davis. 16 pp

Howitt R, Medellín-Azuara J, MacEwan D, Lund J and Sumner D. (2014). “Economic Analysis of the 2014 Drought for California Agriculture.” Center for Watershed Sciences, UC Davis. 20pp

Howitt R, Medellín-Azuara J, MacEwan D, Lund J. (2014). “Weathering the drought by drawing down the bank.” California WaterBlog. July 15, 2014

Lund J. (2014) “Could California Weather a Mega-Drought?California WaterBlog. June 29, 2014

Medellín-Azuara J. (2015). “Drought killing farm jobs even as they grow.” California WaterBlog. June 8, 2015

Medellín-Azuara J. (2015). Jobs per drop irrigating California crops.” California WaterBlog. April 28, 2015

Sumner, D. (2015) “Food prices and the California drought.” California WaterBlog. April 22, 2015

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The hard work of sustainable groundwater management


Groundwater users in the Main San Gabriel Basin clashed with downstream users as the region transitioned from citrus groves to sprawling suburbia. The competing interests eventually worked out a court-approved agreement over pumping rights after a series of difficult and exhausting negotiations. Photos: San Gabriel Valley in 1900 and in modern times. Sources: Covina Citrus Industry Photographs, Covina Public Library; Wikipedia 

By Erik Porse

Under California’s new groundwater law, local agencies must adopt long-term plans for sustainably managing basins subject to critical overdraft. Preparing these plans will be challenging, requiring collaboration and compromise among water users accustomed to pumping as they please.

Local agencies do not know exactly what they’re in for. They’ve never been responsible for achieving “sustainable groundwater management,” as the law requires. However, the histories of adjudicated basins in the Los Angeles area can be instructive. They illustrate the difficult and exhaustive process required in reaching agreement among unregulated groundwater pumpers.

Beginning in the late 1940s, as the post-war suburban boom was taking off, several water utilities and landowners in Southern California turned to the courts to settle disputes over groundwater pumping rights.

Two factors helped the parties reach long-term agreements approved by the courts and codified into law.

First, imported water from the expanding Metropolitan Water District of Southern California (MWD) allowed water users to set less restrictive limitations on groundwater pumping, because additional water was available to the basins.

Second, water users had to learn to communicate and negotiate before deciding how to allocate pumping rights. They did this first through informal working groups, and then through formalized institutions and regulations. The groups had to make a long series of decisions in financing engineering assessments of safe yield, negotiating with MWD for imported water and dealing with neighboring basins affected by their pumping.

The Long Beach Judgment

The making of a 1965 groundwater agreement known as the Long Beach Judgment is particularly illustrative. The settlement governs groundwater flows between the “Upper Basin” (Main San Gabriel Basin) and the “Lower Basins” (the Central and West Coast groundwater basins) of Los Angeles County. Carl Fossette, a lead player in the negotiations, recounted the talks in a short 1986 book, “The Story of Water Development in Los Angeles County.”


Map by Megan Nguyen/UC Davis and Eric Porse/UCLA

Rapid urbanization and prolonged drought in the 1940s put these basins into severe overdraft, where groundwater use greatly exceeded the amount that could be replaced.

Water users in the Lower Basins had spent millions of dollars supplementing and recharging their groundwater supply with imported Colorado River water from MWD. Those in the Upper Basin, however, had no plans to curtail pumping or buy imported water, and had done little to replenish groundwater.

The disparity grated on water users in the Lower Basins because most of their natural groundwater replenishment comes from the Upper Basin, via underground flows through Whittier Narrows. The two sides had to come to terms with the groundwater overdraft to sustain the region’s rapid growth.

Water users organized informally

The Central Basin Water Association took the first step by inviting major Upper Basin users to meet with Lower Basins users in January 1955. The upstream users, in turn, formed the Upper San Gabriel Valley Water Association, headed by Robert Radford, the mayor of Monrovia and a local water expert. Fossette describes their first office as a dingy house “nestled up to a gas station, heavily populated with crawling things which defied eviction.”

Most upstream association members pushed to form a municipal water district and annex to MWD. However, the cities of Alhambra, Azusa, Monterey Park and Sierra Madre broke away to form their own group and avoid contracting with MWD.

Frustration grew in the Lower Basins. In 1958, the Long Beach Water Department sued Upper Basin users for allegedly causing their water tables to drop and sought a determination of upstream users’ water rights.

Lawyers, consultants kept at bay

Early talks among lawyers and engineers were unsuccessful. Then, in 1960, each side formed five-member “lay” negotiating committees, excluding technical and legal staffs in favor of representatives from cities and water associations.

Many of the lay committee members knew each other from other dealings. Professional staff and consultants remained on the sidelines. The technical experts did jointly develop what became the “basic reference book” throughout negotiations, but only occasionally attended talks on a “speak-when-spoken-to” basis.

Negotiators met monthly through early 1961 to produce a breakthrough deal guaranteeing underground flows from the upper to lower basins. The talks then moved to details. Key figures helped secure trust and bridge gaps.

Trusted officials narrowed disputes

Fossette was particularly well positioned for this role, being general manager of water districts in both the upper and lower basins. He was eventually invited to participate in the negotiations.

On Sept. 11, 1963, Fossette instigated a marathon effort to work out an agreement. Negotiators met at the new Edgewater Inn in Long Beach with the intention to “stay there until we reach agreement” (Fossette 1986: 191).

The chairman of the Lower Basins committee walked out on the first day. But negotiations soon resumed:

“After early breakfasts, talks extended until lunch, followed by sessions until dinner hour. Even at the dinner hour, the participants were busy discussing strategy. This schedule of negotiating and wrestling with problems continued for several days. After each session, it was necessary for Fossette and (Ruth) Getches to redraft and retype the documents which had been amended, or simply reworded, and agreed upon” (Fossette 1986: 191-92).

After four exhausting days, the parties checked out of the hotel with a solid pact, later validated by Los Angeles County Superior Court. It was a critical step in securing a region-wide strategy for long-term groundwater management in the county.


Groundwater levels in the Main San Gabriel Basin are measured regularly to track fluctuations in water usage and conservation. The San Gabriel Valley Water Association designed this widget to promote water conservation.

Negotiating groundwater agreements today

As pumpers in basins throughout California develop sustainability plans, they may ponder important considerations for groundwater management today that the Los Angeles area settlements did not address.

For instance, those agreements do not consider water for fish and other environmental uses, even though surface waters and groundwater are closely linked. The adjudications also are silent on water quality. Underground contaminant plumes today affect how the court-appointed watermasters manage groundwater in adjudicated basins.

Southern California groundwater agreements are regarded as models of environmental governance. They formed the basis of a 1965 dissertation by the eminent social scientist Elinor Ostrom, which described how small- and medium-sized groups are able to develop collective agreements that can preserve natural resources. That work led to decades of international research on environmental governance that won her the Nobel Prize for Economics in 2009.

Yet, past results do not guarantee future victories. Local water interests have much hard work to do with late nights and cold pizza before California can declare success in managing its groundwater responsibly.

Erik Porse is a postdoctoral researcher with the Institute of the Environment and Sustainability at UCLA. 

Further reading

Blomquist W. A. (1992). Dividing the Waters: Governing Groundwater in Southern California. ICS Press

Fossette C. and Fossette R. (1986). The Story of Water Development in Los Angeles County. Central Basin Municipal Water District. Los Angeles, CA.

Hardin G. (1968). The Tragedy of the CommonsScience 162.3859 (1968): 1243-1248

Lund et al. (2015). Creating effective groundwater sustainability plans. California WaterBlog. March 4, 2015

Ostrom E. (1965). Public Entrepreneurship: A Case Study in Ground Water Basin Management. PhD dissertation. UCLA

Ostrom E. (1990). Governing the Commons: The Evolution of Institutions for Collective Action. Cambridge University Press

Porse E., Glickfeld M., Mertan, K., Pincetl, S. (2015). Pumping for the masses: evolution of groundwater management in metropolitan Los Angeles. GeoJournal. doi: 0.1007/s10708-015-9664-0

California’s Sustainable Groundwater Management Act

The Long Beach Judgment. Board of Water Commissioners of the City of Long Beach, et al, v. San Gabriel Valley Water Company et al, Los Angeles County Case No. 722647. Judgment entered Sept. 24, 1965

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Napa County strings together a ‘living’ river


Black-necked stilts hunt in restored Napa River mudflats. Recent habitat improvements have rapidly attracted desirable native species such as these to the downtown area. Photo by Amber Manfree, July 28, 2015

By Amber Manfree

In the historic heart of Napa Valley, a moderate climate and alluvial soils deposited by the Napa River create perfect conditions for world-class cabernets. An acre of vines here sells for around $300,000, or 25 times the state average for irrigated cropland.

Yet a group of landowners have ripped out 20 acres of these prized vineyards to make room for river restoration, with levee setbacks, terraced banks and native plants.

The project runs the length of Rutherford Reach, a 4.5-mile stretch of the Napa River between St. Helena and Oakville. Landowners say the changes will bring economic benefits over the long term by reducing crop losses from floods and plant disease. Most of all, they feel good about giving back to the river that has brought them so much.

Rutherford Reach is one several sites undergoing major habitat and flood control improvements on the Napa River. Some projects started more than 40 years ago. Others are just getting off the ground.

Far from postage-stamp restorations, these efforts are steadily transforming a huge swath of wetlands in a very lived-in area, re-establishing geomorphic function at the landscape scale.

Innovative funding, inclusive planning and adaptive management power these projects and offer lessons for river restoration elsewhere.

With the completion of ongoing projects, tens of thousands of acres and about 60 percent of the Napa River’s length will have been rejuvenated with improved habitat, intact geomorphic function and reconnected floodplains. Map by Amber Manfree/UC Davis

With the completion of ongoing projects, tens of thousands of acres and about 60 percent of the Napa River’s length will have been restored with improved habitat, intact geomorphic function and reconnected floodplains. Map by Amber Manfree/UC Davis

Here’s a closer look at three major flood control and river rejuvenation projects on the Napa: Rutherford Reach, downtown Napa and the lower Napa River:

Rutherford Reach: a landowner-­initiated restoration

For decades, landowners along the Rutherford Reach struggled with bank instability and floods. The river was confined to create more space for vineyards while upstream dams reduced sediment delivery, leading to incision and eventually lowering the riverbed six to nine feet.

Without a healthy stream profile, desirable river processes and species were lost. Invasive plants such as giant reed and Himalayan blackberry overtook the banks, further degrading habitat and hosting problem insects. 

Then, in 2002, a group of influential vintners organized as the Rutherford Dust Society approached Napa County about partnering to restore the reach, and a new path to restoration unfolded. The landowners:

  • Led the initiative and were involved throughout the planning process
  • Are making meaningful contributions of land and money
  • While motivated in part by economic considerations, they find conservation to be its own reward

More than two dozen landowners support the $20 million restoration and its long-term maintenance, each paying an annual fee based on the linear feet of river crossing their property. Altogether, the landowners will contribute about $2 million over 20 years. The project also is supported with $12 million from a county bond measure and $7.7 million in state and federal grants.

County partnership gives landowners better control over the spread of Pierce’s disease, a grapevine-damaging bacterium spread by sharpshooter insects, said Jeremy Sarrow, a specialist with the Napa County Flood Control and Water Conservation District.

A section of Rutherford Reach, before and after restoration. Source: Napa County Resource Conservation District

A section of Rutherford Reach, before and after restoration. Source: Napa County Resource Conservation District

The county can accommodate landowner requests for removal of riverside plants that host the disease, an action requiring a state Department of Fish and Wildlife permit. The agency generally does not grant these river modification permits to private landowners. Also, the State Water Resources Control Board requires landowners in this reach to show how their land management controls the amount of fine sediment entering the river, and participating in restoration can earn them a waiver.

Importantly, the landowner funding supports long-term monitoring of restoration, with any excess rolled into an interest-bearing fund for unexpected maintenance costs.

County staff have spent 10 years monitoring the transition from degraded to restored riparian corridor, revising techniques as they go. If something isn’t working – invasive weeds are popping up, a log jam blocks fish passage, an herbicide kills non-target species – the corrections can be made in the field, and landscape processes continue in the intended direction instead of backsliding.

With the first 4.5 miles of riparian corridor construction wrapping up, project managers are preparing to restore 9 more miles just downstream between Oakville Cross Road and Oak Knoll (See map). Together, these projects will transform habitat along 25 percent of the river’s 55 miles.

Downtown Napa: Redesigned flood control revitalizes city core

Napa was built on a particularly flood-prone site: a broad plain at the confluence of the Napa River and Napa Creek -- a flood hazard in its own right. The city center also is on the neck of an oxbow, the river's overflow valve during floods. Further, the buildup of water here is compounded by incoming tides, which push was upstream. Source: Google Earth

Napa was built on a particularly flood-prone site: a broad plain at the confluence of the Napa River and Napa Creek, which is a flood hazard in its own right. The city center also is at the downstream end of the neck of an oxbow, the river’s overflow valve during floods. The buildup of water here is compounded by incoming tides, which push water upstream.

At least 22 serious floods have inundated Napa since 1865, which means locals have been sandbagging their doorways once every seven years or so since the town was on the map. These days, a revolutionary flood control project is reshaping the city center.

In the mid-1990s, the community rebuffed an Army Corps proposal to dredge, straighten and armor the banks of the Napa River. Stakeholder disagreement and funding gaps had hindered flood control throughout the 1900s, but this time things were different.

Residents insisted on a design that improves the environment and makes the river a focal point of downtown. Agencies responded by assembling a community coalition of many residents, local nonprofits, the Army Corps and county flood control officials. The group engaged in a lengthy planning effort and developed a “living river” design. The plan was to accommodate both floods and the environment by removing armored banks and reconnecting the river to its historical floodplain.


Jeremy Sarrow of the Napa Flood Control District leads a recent tour of the Napa River restoration for the UC Davis Center for Watershed Sciences. The stepped floodwall doubles as an amphitheater in downtown Napa. Photo by Stacy Han/UC Davis

Fifteen years later, 7 miles of the downtown reach have been transformed both visually and functionally.

The confluence of Napa Creek and the Napa River has been extensively reshaped, providing space for floodwaters and improved conveyance. Native plants such as tules, alders and willows stabilize banks.

Meticulously engineered placement of woody debris has made the streams more hospitable for salmon and steelhead trout. Napa Creek overflow channels as wide as boxcars are buried under streets.

Seven bridges and two railroad trestles have been reconstructed at higher levels and dozens of buildings have been torn out to make way for the river.


The 2002 photo on left shows the Hatt Building, an abandoned 19th century storehouse, and a more recent warehouse perched on a steep bank with poor quality habitat. Today, the Hatt is an upscale shopping and dining destination protected by floodwalls with a sculpture garden promenade and the warehouse has been removed to give the river room to handle bigger flows. Photos by Caetlynn Booth (L) and Amber Manfree.

Capacity-increasing overflow basins and the enormous Oxbow bypass look and function like parks when water is at normal levels. The parks, which connect to riverside walking and biking trails, are used for community events year round.

In all, planners estimate they have tripled the river’s capacity while improving habitat and bolstering the local economy. The Army Corps views the effort as a pilot project for flood-prone communities.

The lower Napa: steady, strategic land acquisitions for conservation

At the mouth of the Napa River, a vast wetland complex has quietly become the second-largest tidal restoration project in California, after the South Bay Salt Pond Restoration Project near San Jose. The reserve system grew steadily over the past 40 years, eventually encompassing more than 35,000 acres of wetlands encircling San Pablo Bay.

San Pablo Bay National Wildlife Refuge, one of the oldest of the reserves, now spans more than 10,000 acres near the mouths of the Napa River and Sonoma Creek. Building on this foundation, the Land Trust of Napa County along with county and state agencies have strung together properties along 12 miles of the Napa River to extend the reserve system north from Mare Island to Napa. Today, this network provides habitat, recreation and increased flood capacity. 

In addition, tidal flows are returning and marshes are renewing themselves across 13,000 acres of former salt evaporation ponds and hayfields on the north shore of San Pablo Bay, now part of the state-managed Napa-Sonoma Marshes Wildlife Area.

The South Napa Wetlands Opportunity Area, 1,200-acre component of the flood control project, ties the downtown improvements with the downstream string of estuarine wetland reserves. Breached and lowered levees give floodwaters a safe place to spread out, increasing flood capacity and conveyance downtown and reconnecting the river to its floodplain and tidal marsh.

Both habitat and geomorphic function are being restored throughout the lower Napa River. With every additional levee breach, the area is increasingly hydrologically connected to the San Pablo Bay region.

Rejuvenating a sense of place

Each of these restoration efforts was driven by communities with a strong sense of place and an appreciation of the environment, along with a practical need for flood control and a societal imperative to bring back the salmon.

With the completion of ongoing projects, tens of thousands of acres and about 60 percent of the Napa River’s length will feature improved habitat, intact geomorphic function and reconnected floodplains.

With experience gained through adaptive management, project managers are increasingly skilled in restoring landscape processes. The accrued knowledge will be an asset to future work.

Residents await the next big flood with a new attitude, less afraid and more curious to see how well the redesign will perform. The Federal Emergency Management Agency is revising flood risk zones to reflect improvements, which will lower insurance rates for many.

Years of field surveys will be needed to assess restoration project outcomes for the river’s other residents: the birds, fishes and mammals. Judging by appearances, habitat is already much more appealing to wildlife.

Pond turtles, ducks, geese, and egrets are common within a few steps of First and Main streets in downtown Napa. Beavers have recolonized surprisingly fast, felling newly planted cottonwoods and building dams at the Rutherford Reach and even on Napa Creek just off Main Street.

The definitive test will be what happens with native salmon and steelhead, as hopes for their return have guided much of the habitat restoration.

Amber Manfree, a native of Napa County, is a geographer and postdoctoral researcher with the UC Davis Center for Watershed Sciences. She co­-edited the 2014 book, Suisun Marsh: Ecological History and Possible Futures.”

Further reading

Fimrite P. 2011. “Napa River restoration project serves as model.” San Francisco Chronicle. Dec. 10, 2011

Napa River/Napa Creek Flood Protection Project, Napa County

Photo Gallery: Napa River Flood Protection Project: Hall Building to First Street. MGE Engineering Inc of Sacramento

Napa River Flood Protection Project: Hatt Building to First Street, Napa, CA, MGE Engineering Inc. of Sacramento

Rutherford Dust Society



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