Will Delta Smelt Have a Happy New Year?

by James Hobbs and Peter Moyle

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

If our wishes were fishes, Delta Smelt might survive.

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

Further reading:

Hobbs, J.A, P.B. Moyle, N. Fangue and R. E. Connon. 2017. Is extinction inevitable for Delta Smelt and Longfin Smelt? An opinion and recommendations for recovery.  San Francisco Estuary and Watershed Science 15 (2):  San Francisco Estuary and Watershed Science 15(2). jmie_sfews_35759. Retrieved from: http://escholarship.org/uc/item/2k06n13x

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

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

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

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

Moyle, P. B., L. R. Brown, J.R. Durand, and J.A. Hobbs. 2016. Delta Smelt: life history and decline of a once-abundant species in the San Francisco Estuary. San Francisco Estuary and Watershed Science14(2) http://escholarship.org/uc/item/09k9f76s

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

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

New paths to survival for endangered winter run Chinook salmon

by Anna Sturrock and Corey Phillis

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

How did we discover their secret stop-offs?

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

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

What are the implications?

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

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

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

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

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

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

 Further reading

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

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

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

Posted in Biology, Fish, Salmon | Tagged , | 5 Comments

Beginning of 2018 drought? – December 31, 2017

High and prepip lows for California December 2017

by Jay Lund

Every year is different for water management in California.

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

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

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

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

Here is some simple statistical analysis on three reasonable questions.

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

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

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

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

December vs Water Year Precip for N Cal

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

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

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

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

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

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

Progression of dry years in Sacramento Valley

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

Annual runoff correlation for Sacramento Valley

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

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

Further Reading

CDEC, The mighty California Data Exchange Center, http://cdec.water.ca.gov/index.html

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

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

Swain, Daniel (2017), “Strikingly dry conditions persist; Thomas Fire now largest California wildfire,” December 24, 2017, http://weatherwest.com/archives/6030

Swain, Daniel (2017), “New insights into the Ridiculously Resilient Ridge & North American Winter Dipole,” December 4, 2017, http://weatherwest.com/archives/5982

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

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

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

Posted in California Water, Drought | Tagged | 5 Comments

Nudging progress on funding safe drinking water

by Jay Lund

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

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

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

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

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

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

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

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

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

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

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

A partially voluntary public goods charge for safe drinking water

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

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

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

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

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

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

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

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

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

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

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

Further reading

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

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

SB623 language – https://leginfo.legislature.ca.gov/faces/billTextClient.xhtml?bill_id=201720180SB623

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

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

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

Making water for the environment count in an era of change: Cautionary tales from Australia

by Alison Whipple

Floodplain forests of the Ovens River near its intersection with the River Murray, Australia. © J Pittock 2017

The specter of California drought looming again on the horizon gives renewed urgency for water policy and management reforms. Recent discussions reflect a growing recognition that our future depends on us making water count for both humans and the environment. For much of our state’s history, water has counted primarily in its capacity to supply water for cities and agriculture. Continued declines in California’s freshwater ecosystems and new and amplified threats under climate change make it clear additional reform is needed to maintain the character, functions and services of our riverine landscapes.

Sustaining California’s native freshwater ecosystems has been a persistent challenge even under the best of conditions, and in an era of climate change, compounding factors expand this challenge. These issues are addressed in a recent Public Policy Institute of California report, which identifies needs for reforms to improve water accounting for environmental purposes, develop watershed-level plans, and establish ecosystem water budgets.

Efficient and effective strategies to establish and implement needed reforms such as these can be found in other systems, as managing water for the environment is a global challenge. And, places similar to California – defined by scarce and variable supply, high demand, and a large diversified economy – are more likely to provide useful insights. With comprehensive water reform currently underway, Australia’s Murray-Darling Basin offers just such an opportunity.

Degraded River Murray floodplains suffering from lack of water, salinity, and acidification. © J Pittock 2009

The Murray-Darling Basin shares many physical and socio-economic characteristics with California’s Sacramento-San Joaquin Basin. Both climates are highly variable, dominated by cool, wet winters and warm, dry summers and marked by severe droughts and floods. Water availability is often out of sync with when it is needed for agriculture, resulting in extensive water supply infrastructure to store and move water. Irrigated agriculture dominates water usage, and both the Murray-Darling and Sacramento-San Joaquin Basins are often referred to as the “food baskets” of their nations. Also common to these systems is extensive ecosystem degradation, marked by native species declines.

Profound vulnerabilities were revealed during recent droughts, Australia’s Millennium Drought and California’s 2012-2016 drought. Rising temperatures, overall reduced water availability, and greater extremes under climate change place additional pressure on the physical and political capacity of these systems to reliably supply water for humans and the environment.

Australia’s current water reform process is one of the most ambitious globally on several fronts, including its limitations on consumptive water use, establishment of water markets, and large-scale comprehensive planning and management framework across multiple levels of government (Grafton et al. 2016, Hart 2016). A fundamental principle is that freshwater ecosystems are legitimate “users” of water. Under the 2007 Water Act, the Murray-Darling Basin Authority was established and charged with creating a plan for a “healthy working river.” After a contentious drafting process, the Murray-Darling Basin Plan became law in late 2012 with nearly complete implementation by 2019. As the Plan moves from planning to implementation phases, a number of issues have arisen that hinder progress and chances for success, especially under climate change (Hart 2016, Pittock et al. 2015, Wentworth Group of Concerned Scientists 2017).

What follows are cautionary points developed through conversations with Australian researchers as well as from published literature concerning water management in the Murray-Darling Basin. These build on four general lessons for California previously identified by the Public Policy Institute of California based on environmental water reforms in Victoria, Australia, a state covering part of the Murray-Darling Basin: 1) Plan prior to droughts, 2) Support strong federal and state partnerships, 3) Establish water rights for the environment and allow trading, and 4) Give the environment equal priority among other water users (Mount et al. 2016). As California looks to these guiding principles in the context of its own unique socio-economic and environmental conditions, addressing the following points should improve chances for success:

  1. Apply science-based accounting. Allocate sufficient and accountable water, including buffers for climate change, to meet ecological goals and avoid crossing key ecological thresholds. Apply rigorous environmental flow rules including environmental watering priorities and assurances in times of scarcity. Apply rigorous and comprehensive accounting to insure value is received for public expenditure in water acquisition and restoration programs. This includes careful and coordinated shepherding of environmental water through the system. Demonstrate progress toward achieving goals to maintain momentum for reforms. This requires established and coordinated scientific monitoring using clearly understood measures of success, with sustained funding independent of political cycles.
  2. Hold management accountable. Treat water markets as a useful tool, not a panacea. Address overallocation to prevent less-utilized licenses from compromising effective trading. Consider that robust water markets may not be possible everywhere. Account for flood flows and return flows (from water applied to farms). Clearly articulate priorities with easily understood and measurable objectives. Employ transparent accounting to encourage compliance. Cultivate trust and enforcement, which includes demonstrated authority at the top levels of government, buy-in by all participating government entities, and support for local-level implementation with stakeholder participation.
  3. Carefully consider complementary measures. Consider complementary measures and ecosystem-based adaptations to address the many stressors degrading freshwater-dependent ecosystems. This is especially important for supporting resilience under climate change. Evaluate risks of hard engineering infrastructure constructed in the name of efficiency as a replacement for water, including potential maladaptation to climate change. These should be seen as emergency measures rather than standard management tools. Implement regular review of large infrastructure (e.g., dams) to assess performance and implement adaptive management of operations.
  4. Manage at the basin scale. Manage for process and function instead of static conditions, with the goal of health for whole rivers rather than site-by-site and species-specific objectives. Manage for variability, not average conditions. Account for altered variability under climate change using a range of scenarios, as planning based on past extremes may not be adequate. Integrate groundwater and surface water planning and management. Avoid the exchange of surface water for groundwater as surface water restrictions tighten. Seek social, political and financial solutions in addition to technical.
  5. Specifically consider climate change. Do not defer climate change adaptation. Be proactive instead of reactive in planning and employ no- or low-regret options that support ecosystem resilience under change. Develop priorities under climate change to know what to conserve, what to let shift, and what may need to be let go. Prioritize conservation of less impacted systems, such as free-flowing rivers. Consider how other human responses to climate change may affect water resources.

As the implementation of water reforms in the Murray-Darling Basin reveals these and other challenges, it would be wise to take note as California continues with water reforms to make water for the environment count in an era of change.

Alison Whipple is a PhD Candidate in Hydrologic Sciences at UC Davis and affiliated with the Center for Watershed Sciences.

This work and my recent trip as a visiting researcher in Australia were made possible by the National Science Foundation under IGERT Award #DGE-1069333, Climate Change, Water, and Society at UC Davis and the Delta Stewardship Council Delta Science Program under Grant No. 2271. The contents of this material do not necessarily reflect the views and policies of the Delta Stewardship Council, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the Delta Stewardship Council or the National Science Foundation.

I thank the many researchers who generously shared their time and insights, helping untangle the story of where the Murray-Darling Basin Plan is now and where it is going to sustain healthy ecosystems into the future. Special thanks to Associate Professor Jamie Pittock and Professor Stuart Bunn for hosting my visits at the Australian National University’s Fenner School and Griffith University’s Australian Rivers Institute.

Further reading

Australian Broadcasting Corporation. 2017. Pumped: Who’s benefitting from the billions spent on the Murray-Darling? Four Corners, Australia.

Finlayson, C. M., S. J. Capon, D. Rissik, J. Pittock, G. Fisk, N. C. Davidson, K. A. Bodmin, P. Papas, H. A. Robertson, M. Schallenberg, N. Saintilan, K. Edyvane, and G. Bino. 2017. Policy considerations for managing wetlands under a changing climate. Marine and Freshwater Research.

Grafton R., Q., J. Horne, and S. A. Wheeler. 2016. On the Marketisation of Water: Evidence from the Murray-Darling Basin, Australia. Water Resources Management 30:913-926.

Hart, B. T. 2016. The Australian Murray–Darling Basin Plan: challenges in its implementation (Part 1). International Journal of Water Resources Development 32:819-834.

Horne, A. C., J. A. Webb, M. J. Stewardson, B. D. Richter, and M. Acreman. 2017. Water for the Environment: from Policy and Science to Implementation and Management. Elsevier, Cambridge, MA.

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

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

Pittock, J., J. Williams, and R. Grafton. 2015. The Murray-Darling Basin plan fails to deal adequately with climate change. Water: Journal of the Australian Water Association 42:28.

Wentworth Group of Concerned Scientists. 2017. Five actions to deliver the Murray-Darling Basin Plan ‘in full and on time. Wentworth Group of Concerned Scientists, Sydney, Australia.

Posted in Around the World, Climate Change, Planning and Management, Sustainability | Tagged | 1 Comment

A Water Right for the Environment

by Brian Gray, Leon Szeptycki, and Barton “Buzz” Thompson

Waterways meander throughout farmlands in the Delta. (Photo: CA Dept. of Water Resources, shot 3/24/2008)

California’s management of water for is not working for anyone. Environmental advocates argue that state and federal regulators have set water quality and flow standards that do not adequately protect fish and wildlife, and have not enforced these requirements when they are most needed. Farm and urban interests claim that these regulations have been ineffective and cause unnecessary economic harm. These water users may incur additional cutbacks in their water supplies if regulators conclude that more water is needed to support struggling fish populations, making planning for producers difficult. Amidst this tension, native fish populations in the state have continued to plummet.

This ironic situation—in which both sides believe they bear a disproportionate burden of water shortages and regulatory uncertainty—cries out for reform. We should start by granting the environment a water right, as detailed in a new report we helped write for the Public Policy Institute of California.

* * *

California’s native fish species have long struggled against the cumulative effects of land and water resources development for agricultural, business, and residential purposes. Dams have blocked access to spawning grounds, reservoir operations have altered river flows, land development has degraded essential habitat, and diversions for water supply have severely reduced the volume of water in many California rivers.

Stressors on fishes are especially pronounced when precipitation and runoff are diminished. During the 2012–16 drought, for example, a parasite known as “ich,” which thrives in low water conditions, infected adult Chinook salmon returning to spawn in the Klamath and Trinity Rivers . The State lost two consecutive wild cohorts of endangered winter-run Chinook salmon when waters warmed on the Sacramento River below Shasta Dam. And the populations of several species that inhabit the Sacramento–San Joaquin Delta declined to historically low levels as flows and water quality diminished throughout the estuary.

Although many have tried to address the drought’s challenges creatively and cooperatively, two opposing viewpoints have dominated the political debate. Water users—especially San Joaquin Valley farmers—complain that the water quality and endangered species requirements compounded the severity of the drought and deprived them of valuable water. Signs along Interstate 5 to “Stop the Congress Created Dust Bowl” are manifestations of this resentment.

In contrast, environmental and fishing advocates argue that native fish are in peril because state and federal regulators too often compromise on enforcement of these standards, especially during drought. They point to operational and regulatory decisions that diverted water from Trinity River reservoirs until salmon actually began to die, kept too little water in Lake Shasta to provide cold water releases for juvenile salmon, and loosened Delta salinity standards to facilitate water exports for farms and cities. Their claims are backed up by evidence of plummeting populations of key aquatic species.

* * *

These unfortunate events show that the existing regulatory structure is not working for any party. We recommend that California move away from the long-standing policy of protecting water quality and instream flows by restricting the exercise of water rights, and instead foster a new policy that integrates environmental uses into the water rights system. This reform will increase the efficiency and flexibility of environmental water management and enhance certainty for all water right holders.

The centerpiece of our proposal is the creation of Ecosystem Water Budgets (EWBs) for the state’s principal watersheds. An EWB is a defined quantity of water that would be flexibly allocated to meet ecosystem management objectives. This concept includes several key features:

  • Watershed-based planning. Local water managers, water users, and environmental and fishing groups would draft “watershed ecosystem plans” that would determine the volume of water needed to ensure the ecological integrity of each river system. These plans also would designate priorities for the use of the EWB under varying hydrologic conditions.

For example, during periods of relative water abundance, the EWB could be directed to aquatic habitat improvements (such as refreshing spawning gravels) and floodplain and wetlands enhancement for fish and terrestrial wildlife. During drought, when water supplies are scarce for all uses, the EWB would be devoted to critical ecosystem needs—such as cold-water refugia for salmon or wetlands for waterbirds. Planning for ecosystem needs in dry years would perform the dual function of allowing water users to know drought water availability in advance and prepare accordingly.

As with the existing environmental regulatory standards, the ecosystem water assigned to each EWB would carry the highest priority within each watershed. Because the EWBs would largely implement the environmental regulatory standards, the State Water Resources Control Board would review and approve both the watershed ecosystem plans and the EWBs. This priority would be needed to comply with existing laws, and would also implement a key aspect of California water law:  that “public trust” purposes, such as watershed health, must be incorporated into the water rights system.

  • Functional flows and integrated objectives. The quantity of water assigned to each EWB would be based on a “functional flows” assessment of the most effective flow regime for the ecosystem as a whole. This would stand in marked contrast to the current regulatory approach to environmental protection, which focuses on the needs of individual species by regulating individual stressors such as water diversions and discharges of pollutants.

Integrated ecological planning is more realistic because it recognizes that multiple species are adapted to the same flow regime within a single aquatic ecosystem. It is also more efficient because it minimizes the risk of overlapping, and sometimes conflicting, regulatory water requirements.

  • Independent and flexible administration. An independent trustee for the watershed would administer each EWB. The trustee would manage the ecosystem water as an environmental water right with the same prerogatives as other water right holders. The trustee’s primary responsibility would be to deploy the ecosystem water to fulfill the objectives of the watershed ecosystem plan and annual watering plans that define the specific goals of ecosystem water management in light of current and projected hydrologic conditions and water availability.

As with other water right holders, the trustee should have authority to acquire and lease water. Water leases would be limited to circumstances in which there is excess water within the EWB in light of annual ecosystem goals. The proceeds of these short-term sales could then be used to purchase additional ecosystem water during droughts, to fund habitat improvements, and to acquire land and water rights. Moreover, because storage is an essential feature of efficient water management, the trustee should be able to store water—both in surface reservoirs and in underground aquifers—and to enter into surface and groundwater exchange agreements with other users.

The volumes of water assigned to each EWB would not necessarily be the same as those dedicated to ecological purposes under the current regulatory system. The EWB could be greater in watersheds where the existing regulations have proved inadequate to meet the goals of healthy and sustainable fisheries and ecosystems. But it also could require less water—or change the timing and uses of that water—because the EWB would be based on an integrated determination of the needs of the whole ecosystem, rather than fragmented regulatory assessments of individual species requirements. Moreover, each trustee could deploy this water flexibly in light of current hydrologic conditions to achieve targeted biological and ecological benefits. This approach would enable the trustees to use available ecosystem water more efficiently than is possible under existing law. Combined with other improvements in California water management, including improved water accounting and increased groundwater recharge during wet years, the EWB approach has the potential to stem the loss of aquatic species and allow environmental protections to work in better harmony with irrigation and urban water use.

* * *

There are precedents for this form of environmental water management. Several western states and Australia have developed programs akin to ecosystem water budgets, and California has taken small steps toward this approach. For example, water users, environmentalists, and community groups have negotiated agreements on Putah Creek and the Yuba River that provide integrated ecological planning and flexible administration of water for fish and wildlife.

We expect that parties in other river systems will be interested in following these examples. Indeed, the State Water Resources Control Board has proposed designating blocks of water to support ecological uses in the principal tributaries of the Sacramento and San Joaquin Rivers, although currently without the management flexibilities we recommend. This process could be a catalyst for negotiation of EWBs on one or more of these rivers. The Federal Energy Regulatory Commission’s relicensing of hydroelectric dams on several of California’s other important rivers also may serve as a forum for interested parties to pursue more creative and flexible means of managing environmental water. Moreover, because groundwater storage and conjunctive use are components of our proposal, EWBs also may be useful to the parties who are now negotiating groundwater sustainability plans under the recently enacted Sustainable Groundwater Management Act.

* * *

Although negotiated solutions are often the best means of resolving water resources controversies, the Legislature could facilitate the adoption of EWBs by recognizing instream environmental uses as valid water rights or by authorizing the trustees to administer ecosystem water with the same flexibility as other water rights. Legislation to outline the essential features of watershed-based ecological stewardship also would be useful. These include establishing criteria for the assignment of water to ecosystem uses, describing the management powers and responsibilities of the trustees, and defining the relationships of the EWBs to the existing laws and regulations that govern water quality and fisheries.

These changes would promote efficiency and certainty for all water users. Assigning water to the EWBs based on an integrated functional flows approach would direct the available water to the most valuable ecological services within each watershed. And the quantity of ecosystem water would be fixed, providing assurances to other water users in the watershed. The trustees would have to fulfill their stewardship responsibilities within the assigned budget or acquire additional water from other users. Conversely, the assigned ecosystem water would be off-limits to other water users unless they purchase surplus water from the trustees or acquire it through voluntary exchanges.

California’s aquatic ecosystems are fragile and ill-prepared for future droughts and a warming climate. We have a window of opportunity before the next drought strikes to adopt policies that encourage more creative and effective management of water assigned to essential ecological functions.

Brian Gray is a senior fellow at the Public Policy Institute of California and professor emeritus at UC Hastings. Leon Szeptycki is director of Water in the West and professor of the practice at Stanford University. Barton “Buzz” Thompson is the Robert E. Paradise Professor in Natural Resources Law at Stanford Law School.

Additional Reading:

Jeffrey Mount, Brian Gray, Caitrin Chappelle, Greg Gartrell, Ted Grantham, Peter Moyle, Nathaniel Seavy, Leon Szeptycki, and Barton “Buzz” Thompson, Managing California’s Freshwater Ecosystems: Lessons from the 2012–16 Drought (PPIC 2017).

Jeffrey Mount, Brian Gray, Caitrin Chappelle, Greg Gartrell, Ted Grantham, Peter Moyle, Nathaniel Seavy, Leon Szeptycki, and Barton “Buzz” Thompson, Eight Case Studies of Environmental Management During the 2012–16 Drought (PPIC 2017).

Jeffrey Mount, Brian Gray, Caitrin Chappelle, Jane Doolan, Ted Grantham, and Nat Seavy, Managing Water for the Environment During Drought: Lessons from Victoria, Australia (PPIC 2016).

Leon F. Szeptycki, Julia Forgie, Elizabeth Hook, Kori Lorick, and Philip Womble, Environmental Water Rights Transfers: A Review of State Laws (Stanford 2015).

Posted in California Water, Planning and Management, Uncategorized | Tagged , , , | 10 Comments

A Tale of Two Fires: How Wildfires Can Both Help and Harm Our Water Supply

by Gabrielle Boisramé

Lupines blooming in an area that has been burned by multiple natural wildfires.

Now that summer is over and rain has returned to California, it appears that the dramatic 2017 fire season is finally behind us. The effects of fire season can linger, however, with the possibilities of erosion and polluted runoff from burned areas. Napa County has even issued suggestions for how to protect waterways in burned landscapes.

Not all news is bad when it comes to the interactions between fire and water, however. These two seemingly opposite elements can actually work in tandem under the right circumstances, to the benefit of people as well as the environment.

While the North Bay fires were filling the headlines in October, another fire 200 miles away was quietly entering its third month of burning in the Sierra Nevada wilderness. This other fire, known as the Empire Fire, was ignited by lightning. By allowing this fire to slowly burn, the park service allowed natural processes to remove fuels that could otherwise build up and lead to more dangerous fires in the future.

Smoke from the Empire Fire in Yosemite in early October 2017. (Photo: G. Boisrame)

The Empire fire burned through an area in Yosemite where fires have been allowed to burn for over 40 years, the longest period managed with such a strategy anywhere in California. Research in Yosemite and other areas shows that allowing these wilderness fires to burn can increase the amount of water stored in the soil or flowing downstream. In the winter, forest clearings opened up by fires often store deeper snow that melts later than in densely forested areas, meaning more water is released slowly in the spring and summer rather than all rushing out as floods in the winter.

In March 2016, an area with dense canopy cover has almost no snow (left) while only a few hundred feet away an area with burned trees still has snow (right). These photos are from the Illilouette Creek Basin in Yosemite. (Photo: G. Boisrame)

Fires can also open up meadow areas that have been overgrown by forest. Although wet meadows cover only a small percentage of California’s landscape, they provide important benefits to the water supply. Meadows reduce the size of floods by storing water during high runoff periods. They also help to store water for the dry summer months by holding that water like sponges and slowly releasing it.

The biggest news about fire and water, unfortunately, is usually about how burned landscapes contribute to erosion, which then pollutes streams and clogs reservoirs. When fires burn homes, pollution risks can be especially high due to the presence of hazardous chemicals. Fires can also lead to larger floods since there is less vegetation to slow water’s path from rainfall to stream runoff.

These negative effects, however, usually happen because a large portion of a watershed has been completely stripped of vegetation, and plants have not been able to re-grow in time to stabilize the soil. These kinds of fires are usually caused by a combination of dense fuels and extreme weather. When fires burn under less extreme conditions (lower fuel loads, high humidity, low temperatures, and/or low wind speeds), they can clear out dead fuels and remove a small number of trees while leaving most large trees intact. After the fire, the remaining trees (as well as new growth of understory plants) often enjoy wetter soils and less competition. This increases the ability of plants to survive drought conditions.

Wildfire has always been a part of California – especially northern California and the Sierra Nevada – for as long as it has had lush vegetation and dry summers. Native Californian plants have adapted to this process. Some species, like redwoods, even depend on fire for regeneration. Native Californian people historically used fire as a tool to promote the growth of desired plants.

In the early 1900s, however, those in charge came to what seemed to be a very logical decision: to protect our homes and forests from fire, we should put out all fires as quickly as possible. Although this policy was initially very successful, a century later we have flammable forests with heavy fuel loads, as well as densely packed trees that send large amounts of water into the air through their leaves rather than allowing it to flow downstream or remain underground to be used during droughts.

Large public land managers such as the National Park Service and U.S. Forest Service have lately been shifting away from the strategy of suppressing every single fire. Instead, lightning-ignited fires that are burning under acceptable conditions (not too windy, not too close to infrastructure, etc.) are allowed to burn and perform their natural functions of clearing fuels and thinning forests to sustainable tree densities. Prescribed fires and mechanical thinning are also used in situations where greater control is required to reduce risk.

Fire damage is seen from the air in the Coffey Park neighborhood on October 11, 2017, in Santa Rosa, California
(Photo: ELIJAH NOUVELAGE/AFP/Getty Images)

In this way, letting some fires burn today can prevent catastrophic fires from burning through dense fuel in the future. Preventing such catastrophic fires removes their threat to the water supply – as well as the potentially devastating human losses, as we saw from the Atlas, Tubbs, Nuns, and other fires this year. Increased streamflow, snowpack, and drought resistance in burned watersheds all add to this increased water security. The water benefits of more natural forests are receiving increased attention lately, with some companies even working to set up markets for downstream water users to pay for upstream forest care.

We cannot prevent all wildfires in California. However, by understanding their role in our natural systems and incorporating them into our land management, we can benefit from them.

Gabrielle Boisramé has a PhD in environmental engineering from U.C. Berkeley, where she studied the effects of wildfire on water balance in the Sierra Nevada with Prof. Sally Thompson. She continued this work as a post-doctoral scholar with Prof. Scott Stephens, also at U.C. Berkeley.

Further reading

Boisramé, Gabrielle, S. Thompson, B. Collins, and S. Stephens.  “Managed wildfire effects on forest resilience and water in the Sierra Nevada.”

Lundquist, J. D., S. E. Dickerson-Lange, J. A. Lutz, and N. C. Cristea. Lower forest density enhances snow retention in regions with warmer winters: A global framework developed from plot-scale observations and modeling.

Neary, D., K. C. Ryan, and L. F. DeBano. Wildland fire in ecosystems: Effects of fire on soil and water.

van Wagtendonk, J. W. The history and evolution of wildland fire use.

Posted in Planning and Management | Tagged , , | 3 Comments

Duel Conveyance: Delta Tunnel Dilemmas

by Jay Lund

A new option has entered public discussion of Delta water supplies, having only one cross-Delta tunnel instead of two. The official State WaterFix proposal is for two tunnels (totaling 9,000 cfs capacity) under-crossing the Delta for 35 miles to allow up to 60% of Delta water exports to be directly from the Sacramento River for a variety of water supply, water quality, and Delta fish benefits.  Implementing such a major project requires extraordinary political and financial support.  For more than a decade, the group of Delta export water users involved in WaterFix has often lacked internal consensus on the project and its funding.  This is clear today, as cities and water user groups vote differently on WaterFix financing.  Apparent awkwardness of federal water contractor support for WaterFix and the recent Santa Clara Valley Water District vote have again raised the idea of a single smaller Delta tunnel.

In the mid-2000s a single Delta tunnel of 2,500 cfs was proposed to serve urban water agencies.  And in 2013, a group of environmental and urban agencies suggested a single 3,000 cfs tunnel combined with a portfolio of other actions, which was bruskly rejected by the state.  The WaterFix effort’s EIR in 2013 also included a single 3,000 cfs tunnel which was not recommended.  A Public Policy Institute of California op-ed last year suggested one tunnel as a promising alternative, as has a recent Los Angeles Times editorial.  Some suggestion is made that a single tunnel might make additional tunnels in the future easier, if needed.

California needs a viable Delta water supply strategy, given worsening endangered species conditions, the coming end of supplies from groundwater overdraft, sea level rise, continued land subsidence, and the Delta’s inherent structural fragility.  Any Delta water supply solution will be expensive and will need to be paid for.  Many regard the two tunnel proposal as too expensive for its benefits.  Here are some dilemmas for Delta conveyance capacity.

One 3-5,000 cfs tunnel is enough capacity to provide Bay Area and southern California cities with higher water supply reliability and better water quality.  This option has clear water supply and financial benefits for cities and reduces construction and other impacts within the Delta.  If the current state-led effort collapses, a consortium of urban agencies could conceivably embark on their own tunnel project, essentially a peripheral garden hose for urban users.

But one tunnel is not enough capacity to greatly improve water reliability and quality for agricultural water users in the southern Central Valley.  It is also not large enough to greatly reduce unnatural reverse river flows in the central and southern Delta that harm native fish unless accompanied by great reductions in agricultural water use in the southern Central Valley.

The coming end of groundwater overdraft under the Sustainable Groundwater Management Act will likely lead to substantial land fallowing and increased agricultural pressure to maintain or expand Delta exports, commensurate with current attention to recharging aquifers with floodwaters.  Even if federal arrangements continue to disrupt CVP contractors’ ability to financially support WaterFix through the CVP, some more prosperous contractors and groundwater-dependent San Joaquin Valley farmers might see financial benefits from improved Delta export reliability as new State Water Project contractors, sub-contractors, or water or conveyance capacity purchasers.

Another aspect is that many Delta land owners depend on water project pumping from the southern Delta to bring fresher Sacramento River water to the central and southern Delta.  (The Delta has two major salinity sources, seawater to the west and drainage from the San Joaquin River.)  State subsidies for Delta levees are easier if the state has an interest in these levees for maintaining through-Delta water exports.  Larger tunnels could reduce outside water and financial subsidies for in-Delta water quality and levees.

Would solving Delta water supply problems for cities reduce their involvement in finding solutions for the environment, Central Valley agriculture, and Delta levees and make solving overall Delta problems harder?

The state needs effective Delta policies in three areas – water supply for urban, agricultural, and in-Delta users, environmental management for declining native species, and levee protection or retreat for subsided islands which are uneconomical for landowners.  These policies often interact for good and ill.  State agencies continue to work on these strategies fitfully, across many agencies and programs, with more focused attention than in past decades.  Levee conditions have been improving, but environmental and water supply conditions continue to deteriorate.

It is good to see middle ground alternatives come forward, but there will be no perfect solutions for the Delta’s problems.  Imperfections will be seen differently by different interests.  We remain largely in a game of chicken, where each interest refrains from public compromise (or maintains that it has already compromised enough) to avoid weakening its negotiating position.  But time is passing, and fish conditions worsen.  Sustained State leadership is needed to craft imperfect but workable solutions among conflicting interests.

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

Further readings

BDCP (2010), “Analysis of Tunnel Sizing, BDCP Steering Committee, New Conveyance Sizing,” powerpoint presentation July 1, 2010, http://baydeltaconservationplan.com/Libraries/Dynamic_Document_Library_-_Archived/7_1_10_BDCP_Sizing_Presentation.sflb.ashx

CCWD (2008), Comment letter on ‘Notice of Intent (April 15, 2008) and Notice of Preparation (March 17, 2008) of the Environmental Impact Report/Environmental Impact Statement (EIR/EIS) for the Bay Delta Conservation Plan (BDCP)’, May 30, 2008, Contra Costa Water District, CA.  http://www.ccwater.com/DocumentCenter/Home/View/1972

CCWD (2009), Comment letter on December 17,2008 Draft of ‘An Overview of the Draft Conservation Strategy for the Bay-Delta Conservation Plan’, July 2, 2009, Contra Costa Water District, CA. http://www.ccwater.com/DocumentCenter/Home/View/1976

Green, E., “Sorry, my fellow environmentalists, we have to build the delta tunnels,” Los Angeles Times, op-ed, 9 October 2017.

Lund, J., “Delta “chicken” – A tragedy, CaliforniaWaterBlog.com, 15 February 2011

Lund, J., E. Hanak, W. Fleenor, R. Howitt, J. Mount, and P. Moyle, Envisioning Futures for the Sacramento-San Joaquin Delta, Public Policy Institute of California, San Francisco, CA, 300 pp., February 2007.

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

Moyle, P. and J. Hobbs, “California WaterFix and Delta Smelt,” CaliforniaWaterBlog.com, August 13, 2017

Nelson, T., H. Chou, P. Zikalala, J. Lund, R. Hui, and J. Medellin-Azuara, “Economic and Water Supply Effects of Ending Groundwater Overdraft in California’s Central Valley,” San Francisco Estuary and Watershed Science, Volume 14, Issue 1, 2016.

NRDC, “Portfolio-Based Conceptual Alternative for the Bay-Delta, Overview,” Natural Resources Defense Council, January 16, 2013  https://www.nrdc.org/resources/portfolio-based-conceptual-alternative-bay-delta

Weisser, M. (2017), “Could a Simpler Delta Tunnel Solve Years of California Water Conflict?”, Water Deeply, 31 October 2017.

Posted in California Water, Delta, Sacramento-San Joaquin Delta | Tagged | 1 Comment

Moving Salmon over Dams with Two-Way Trap and Haul

by Peter Moyle and Robert Lusardi

Image source: Fisheries 42(9)

Removing Shasta Dam is the single best action we can take to save California’s wild salmon.  Not possible, you say?

Then there are two alternatives.

One is to provide plenty of cold water and diverse, highly managed habitat below dams. The other is to transport fish to now-inaccessible habitat above dams.

(A third option might be improved management of hatcheries; however, to avoid the pitfalls of domestication that come with hatchery production, our focus is on wild, naturally spawning fish.)

The focus of management today involves regulating dam releases to manage flow and temperature, as well as creating new habitat for spawning and rearing, such as floodplains.  Central Valley salmon are so far not doing well under this option.

The second option is being proposed by fisheries agencies (mainly NMFS), moving fish above the dams. Seventy percent of all salmon habitat is now above impassible dams.  Given that it is nearly impossible to construct fish ladders over California’s large dams, current management proposals involve what we call “two-way trap and haul”.

Basically, adult fish are trapped below dams, then trucked and released in rivers above dams.  If the transported fish spawn successfully, juveniles are then trapped as they move downstream to lower sections of river or into a reservoir.  After trapping, juveniles are trucked for release below dams, allowing them to migrate to sea.

Sound good?  Well, there are some problems to overcome.

First, many adult fish die after being transported, due to stress and other factors. This issue has largely been resolved, however, and there are many success stories of transporting adult salmon over barriers.

Second, habitat conditions above dams are different from historical conditions. In California, most of these upstream rivers have been without salmon, and the influx of ocean nutrients they provide, for 60-70 years.  Besides water quality, other changes to upstream habitat can include stream flow, temperature, channel morphology, and  potentially competing resident fishes (including introduced species such as brown trout).

Third is the difficulty of capturing out-migrating juveniles before they reach the reservoir. Juvenile traps must work under a wide range of reservoir surface elevations and during sudden high flow events, when most juveniles move downstream.  Juvenile capture is among the most difficult hurdles to overcome and capture rates are low. The current favored proposal for the McCloud River is a trap at the mouth of the McCloud River.  To keep the water cool enough for salmon, a temperature curtain is proposed, based on modeling, which will prevent cool water from sinking until it is past the collector.

Fourth is the problem of releasing captured juvenile salmon after transport and expecting them to survive in the river after the stress of capture and transport.  These fish also must face all the below-dam problems that non-transported fish face during outmigration, including passage through the Delta, degraded water quality, and predation.

Overcoming these problems is essential to making two-way trap and haul work.  NMFS proposes this technique to establish above-dam populations of Central Valley steelhead, spring-run Chinook salmon, and winter-run Chinook salmon, all listed under state and federal endangered species acts (ESAs).

Steelhead should not be included in this list because they do not need the protection of the ESAs for complex reasons.  Also, most reservoirs support steelhead-like rainbow trout that live in the reservoirs and migrate up tributaries to spawn, likely making it more difficult for introduced steelhead to establish.  Some reservoirs also have land-locked populations of Chinook salmon.

Spring-run and winter-run Chinook need additional protection at all life history stages, including the need to have multiple populations across the landscape. Thus, two-way trap and haul seems to have potential to aid that aspect of recovery.  The requirements of the two runs are somewhat different, so we focus on winter-run Chinook salmon because it is also the main focus of NMFS efforts.

The urgency of developing new approaches for winter-run conservation increased during the 2012-2015 drought, when low flows, combined with mismanagement of the coldwater pool in Shasta Reservoir, resulted in the near-extirpation of naturally spawned fish in the Sacramento River.  The run was saved mainly by a hatchery program at the Livingston Stone facility below Shasta Dam.

Of all the Chinook salmon runs in California, Sacramento winter-run is the most distinctive by genetics and habitat requirements.  Here is a salmon that lives at the southern end of the range of the species, yet it incubates its eggs, the most temperature-sensitive life stage, during the hot days of summer. Originally, it accomplished this amazing feat by spawning in the McCloud River. Historically, the McCloud was a good-sized, cascading river, fed by giant cold-water (7-8°C) springs  all year around. Winter-run spawned in the McCloud so their young would hatch during late summer when there would be little competition from the young from other salmon runs.  Eventually they would migrate downstream to the productive Pit River, which in turn flowed into the Sacramento River.  Small juveniles likely reached the Sacramento Valley in time to catch the annual flooding of riparian lands and forests, where food and cover were abundant so fish could grow fast and fat.  As floods receded, winter-run moved off the floodplains, down the river, and out to sea.

Of course, winter-run Chinook were not alone. The McCloud River in the 19th Century was regarded as the most productive salmon stream in California and was the site of the first fish hatchery in the state.   All four runs of Chinook salmon spawned there, as did steelhead.  There was almost a continuous influx of spawners, with juveniles of many ages and sizes rearing and then moving out as conditions permitted.  One indication of the unique nature of the McCloud is that it was the only river (as far as we know) to support bull trout, a cold-water loving trout that preyed upon abundant juvenile salmon.  It is now extirpated from the river and the state.

The McCloud River, July 2014 (Photo credit: Peter Moyle)

But the historic McCloud River is no more.  Over 80% of the cold spring water flowing into McCloud Reservoir is diverted for hydropower production, making the river below the dam smaller and the water somewhat warmer. Below-dam tributaries increase flows in the main river and create a more natural river flow regime, including flood events.  Shasta Reservoir covers the lowest and presumably once-most productive reaches.  The Pit River is a staircase of hydropower dams.  Winter-run Chinook have survived by establishing a population in non-historical habitat immediately below Shasta Dam, where cold water releases from the reservoir are managed for their continued existence.

Today, winter-run Chinook depend on these flows and on gravel dumped in the river below Keswick Dam and Red Bluff to improve spawning. As a backup, a few are reared through their entire life cycle at the Livingston Stone Hatchery at the base of the dam; the hatchery has chillers to keep the water cold.

Winter run Chinook are in a desperate situation; they are on the brink of extinction, especially as wild fish.   Hence, they are NMFS’ prime candidates for two-way trap and haul, between the Sacramento and McCloud rivers. Presumably, the operation will be conducted initially as an experiment, to see if a back-up population can be established that can persist through years of severe drought.  This will not be easy.

Here are a few of the problems that must be dealt with in tandem:

  • The McCloud of today is a smaller, shorter river than the original river and it has not been fertilized by salmon for 70 years.
  • The McCloud River supports substantial populations of potentially competing rainbow and brown trout.
  • Capture of out-migrating juveniles will require a trap in or just above the reservoir that can work during rapid reservoir fluctuations and during all flows, including high flows.
  • The release program for captured juveniles must result in survival rates as high or higher than naturally spawned fish in the Sacramento River.
  • The trap and haul program should not take funds and effort away from improving habitats for rearing and migration in the Sacramento River corridor.

Despite these problems, it is likely that a two-way trap and haul program for winter-run Chinook salmon will be established soon.   A pilot study is a top priority action for NMFS in California. We recommend that such a program not be tried on other runs of salmon until it can be demonstrated that the winter-run Chinook program works successfully.  Success should be clearly defined and measured against objective and quantifiable pre-determined criteria.   Ultimately, the recovery of winter run Chinook, and other fishes, will depend on improved/expanded riverine and floodplain habitats, such as proposed in the salmon resiliency strategy of the California Natural Resources Agency.  The alternative is either extinction or maintaining winter-run Chinook salmon as a domesticated oddity.

Peter B. Moyle is a UC Davis Professor Emeritus of fish biology and an associate director of the Center for Watershed Sciences. Robert A. Lusardi is a researcher at the Center for Watershed Sciences and is the CaliforniaTrout-UC Davis Wild and Coldwater Fish Scientist.

Further reading

Lusardi, R. A and P. B. Moyle 2017. Two-way trap and haul as a conservation strategy for anadromous salmonids.

Baumsteiger, J. and P.B. Moyle 2017. Assessing extinction.

California Natural Resources Agency. 2017.  Sacramento Valley Salmon Resiliency Strategy, June 2017.

Clancey, K., L. Saito, K. Hellmann, C. Svoboda, J. Hannon and R. Beckwith 2017. Evaluating head-of-reservoir water temperature for juvenile Chinook salmon and Steelhead at Shasta Lake with modeled temperature curtains.

Moyle, P., R. Lusardi, P. Samuel, and J. Katz. 2017. State of the Salmonids: Status of California’s Emblematic Fishes 2017.

Opperman, J.J, P.B. Moyle, E.W. Larsen, J.L. Florsheim, and A.D. Manfree. 2017 Floodplains: Processes, Ecosystems, and Services in Temperate Regions.

Perales, K.M., J. Rowan, and P.B. Moyle. 2015. Evidence of landlocked Chinook Salmon populations in California.

Posted in Conservation, Fish, Planning and Management, Salmon, Stressors, Sustainability | Tagged , | 9 Comments

The Spawning Dead: Why Zombie Fish are the Anti-Apocalypse

by Mollie Ogaz

The undead, honing back to its natal stream. (Photo credit: Ken Davis)


Imagine you are on the bank of a river or stream in California’s Central Valley. It is just past sunset, leaves rustle overhead, and you feel a tingling along your spine. Suddenly a zombie fish leaps past you, patches of decomposed flesh visible as it streaks by. It’s a thing of nightmares; just a figment of the imagination brought on by the spooky atmosphere, right?


It is a Pacific salmon (Oncorhynchus spp.), making its upstream migration to natal spawning grounds. This arduous journey to reach the stream in which they were born is attempted by each Pacific salmon that manages to survive to adulthood in the ocean. Only 1 in 2,000 will complete this journey. Unlike their Atlantic relatives, Pacific salmon are semelparous, meaning they reproduce only once in their lifetime, so the stakes of failure are high.

These spawning dead remind us about the unlikely success of this species, and why dwindling populations recover over decades, not single seasons. By understanding the challenges these fish face throughout their life cycle, we can appreciate how our natural resource management decisions are really about laying the groundwork for future generations, rather than enacting short-term fixes for ourselves.

The life cycle of a Pacific salmon begins and ends in the same freshwater stream – if everything goes well. Fertilized eggs buried in the gravel hatch into alevin, which derive energy from the attached yolk sac as they gain strength. After leaving the gravel, the small salmon, called fry, rise to the water’s surface to fill their swim bladders and begin to feed.

Depending on the species, fry can spend anywhere from a few weeks to a couple of years in freshwater. As they approach the ocean, juvenile salmon undergo smoltification, a physiological transformation that allows them to live in saltwater, where they spend the majority of their lives feeding in the highly productive marine environment. Entering the ocean marks the end of the first major migration Pacific salmon make in their lifetime, one they will have to complete in reverse in order to reproduce.

Life cycle of Pacific salmon.

Lucky adults that have managed to avoid anglers, disease, predators, and many other dangers make their way back toward their natal stream, initiated by cues that are poorly understood, but likely have to do with reproductive maturation and environmental changes. Once a salmon reaches freshwater, it stops feeding entirely and relies on energy stores accumulated during years in the ocean to support its homeward migration. This natal homing, or ability to navigate upstream to the very waters in which they were born, is one of the most amazing feats in the animal kingdom. To do this, young salmon imprint on the unique smells of their natal stream, which they use as a sort of map to successfully navigate their return.

Here is when things get spooky. Since the salmon have stopped feeding and are putting all of their energy into reaching their spawning grounds and subsequent reproduction, their bodies begin to shut down. The normal energy balance that is kept between growth, survival, reproduction, and body maintenance shifts to solely focus on reproduction. It’s spawn or bust for these salmon; there are no second chances.

The decrepit carcass of an adult salmon. (Photo credit: Ken Davis)

Robust, silvery fish turn into living zombies, flesh decomposing and falling off their battered bodies as they struggle against the current and over obstacles toward spawning grounds. The journey is long and tough, but ultimately worth it if they successfully reproduce.

Upon reaching their natal streams, females build a redd, or nest, in the gravel where they deposit their eggs that are then fertilized by competing males. Shortly thereafter the adults die, although females may guard the nest for a week or two first. The carcasses become a source of nutrients for the aquatic and riparian communities of the stream, including the offspring that will soon hatch. It is a rare cycling of nutrients from the marine environment to freshwater streams, and only possible due to the salmon’s anadromous lifestyle.


Video shows Chinook salmon spawning in Lower Putah Creek, Yolo County, in fall 2014. No sooner does a female lay her eggs than she is flanked by two males, mouths agape as they release clouds of sperm. The female attempts to bury her eggs as several rainbow trout attempt to eat them. Poor girl even hits her head on a rock while covering the eggs. Video by Ken Davis/Wildlife Survey & Photo Service

This Halloween you can add a spooky stop to your list and head to Putah Creek in Winters to see some zombie fish for yourself, where record numbers of spawning Chinook salmon have been observed over the last few years. Last fall there were an estimated 1,000 to 1,600 spawners, a truly remarkable number for a creek that had a high of about 70 returned salmon a little over a decade ago! This rebound shows that changes in management with long-term vision can succeed in returning salmon to local streams. Next up: achieving major management changes in larger, dammed rivers with high political controversy.

Mollie Ogaz is an assistant specialist at the Center for Watershed Sciences.

Further reading

Alvarez, F. 2016. “Record numbers of salmon are spawning in Putah Creek”. The Davis Enterprise. December 28, 2016

California Trout. 2017. “SOS II: Fish in Hot Water”

Cooke S.J., Crossin G.T., and Hinch S.G. (2011) Pacific Salmon Migration: Completing the Cycle. In: Farrell A.P., (ed.), Encyclopedia of Fish Physiology: From Genome to Environment, volume 3, pp. 1945–1952. San Diego: Academic Press.

Moyle, P.B. 2015. “Salmon finding a home in my backyard – Could it be?”. California WaterBlog. March 11, 2015

Tilcock, M. 2016. “The Horror of a Salmon’s Wheel of Misfortune”. California WaterBlog. Oct. 30, 2016

Posted in Biology, Fish, Halloween, Salmon, Wild and Wacky | Tagged | 1 Comment