Drought and the Sacramento–San Joaquin Delta, 2012–2016: Environmental Review and Lessons

by John R. Durand, Fabian Bombardelli, William E. Fleenor, Yumiko Henneberry, Jon Herman, Carson Jeffres, Michelle Leinfelder-Miles, Jay R. Lund, Robert Lusardi, Amber D. Manfree, Josué Medellín-Azuara, Brett Milligan, and Peter Moyle

Droughts are common in California. The drought of 2012-2016 had no less precipitation and was no longer than previous historical droughts (Figure 1), but came with record high temperatures (Figure 2) and low snowpack (Figure 3), which worsened many drought impacts. Water supplies for agriculture and urban users statewide struggled to meet water demands. Conservation and rationing, increased groundwater pumping and a diversified economy helped keep California’s economy robust in most sectors. The drought degraded environmental conditions in the Sacramento-San Joaquin Delta (Delta) as the region became saltier and warmer, invasive weeds spread, and iconic fishes like salmon and Delta smelt had strong declines.

Water demands on the Delta often outstrip its capacity, even in wetter than average years. During the drought, water-demand conflicts increased among human and environmental uses. For example, maintaining Delta outflow and freshwater standards was important to agriculture, drinking water supplies and some sensitive species. To fulfill these downstream needs, upstream water releases from Shasta Reservoir depleted the cold-water pool in 2014 and 2015, increasing Sacramento River temperatures and nearly extinguishing two cohorts of winter-run Chinook salmon.

Fig 1

Figure 1. Cumulative precipitation for water years 2012-2016, compared to average and driest water years (Source: CDEC)

Fig 2

Figure 2. California Mean annual temperature relative to the 20th Century mean (Source: NOAA National Centers for Environmental Information)

Fig 3

Figure 3. California mean April 1 snowpack at Donner relative to the 20th Century mean (Source: CDEC)

To help understand scientific aspects of Delta management during the drought, we reviewed official documentation, reports and data, and spoke with numerous agency managers and scientists (Durand et al. 2020).  State and federal water management priorities for the Delta watersheds were to (1) provide essential human health and safety needs, (2) control saltwater intrusion in the Delta, (3) maintain reservoir capacity, and (4) protect at-risk species. Support for these priorities included reducing reservoir releases, Delta export pumping, and Delta outflow; installing an in-Delta salinity barrier; conserving urban water; reducing agricultural water allotments; increasing salmon hatchery production and trucking; and removing invasive aquatic weeds.

These actions helped maintain the Delta’s environment and its dependent uses.  However, with the exception of a study on the effects of the emergency salinity barrier in the Delta, managers were too occupied with emergency-related responsibilities to apply organized scientific methods to learn and prepare for future droughts.  Our main recommendation is to use the lessons of this drought—and the next—to prepare for the one after that. Indeed, 2020 is another dry year and we may already be in a long-term western US megadrought that will force changes in water policy (Williams et al. 2020). The more we can learn from current and future efforts, the better prepared we will be.

Systematic science-based and stakeholder-inclusive preparation for our future needs to continue despite other pressing priorities. The impacts of the COVID-19 pandemic, related economic hardship, and racial/social injustice are all worsened without effective resource management in our drying, warming climate. The availability of data from long-term monitoring of water quality, plankton and fish populations provide insights when extreme wet and dry periods are compared. Each drought in California’s history has brought changes in water management and policy. As the climate changes, drought effects will become more severe and policies are likely to become rapidly outdated.

We suggest preparing today for anticipated increases in frequency and severity of drought years with the following recommendations:

  1. Pre-drought warnings. Drought timing differs across California’s regions. The Governor’s declaration of drought emergency in 2014 helped solidify a unified response. Preliminary declarations allow diverse water jurisdictions to examine local conditions, and prepare for potential water supply disruptions.
  2. Independent Evaluation. Independent review of water agency data by an interdisciplinary group, such as the Interagency Ecological Program can help managers synthesize and make more environmentally-effective, science-based decisions.
  3. Transparency and Documentation. The internet is a cluttered, unstable place. Recent mandates that support data and policy transparency have increased the clutter, and work at odds to the original intent. For online information to be transparent, professional archivists are needed to ensure that documents and data remain available over time, and do not become dead links.
  4. Scientific Preparation. Drought response often overrode scientific opportunity. The demands on agencies were enormous. Some surveys increased frequency or were extended to monitor drought effects. But to answer long-term questions about the effects of the changing California climate (including droughts), more systematic, science-based  planning is essential.
  5. A Delta drought plan would help managers across agencies organize and prepare resources for the next drought, which might already be beginning. A Delta drought plan should provide a summary of lessons from previous droughts; data analysis; protocols for interagency communication and response; resource deployment and operational contingency plans, with funding and staffing details; and structure to organize a scientific team.
  6. Salinity Barriers. The 2015 Delta salinity barrier program was effective and run like an experiment. Managers should prepare to implement solutions with a similar approach, preparing permits, operational coordination, and scientific monitoring in advance.
  7. Ecosystem Resilience. Vulnerable animal populations become more threatened during droughts. Interventions are less costly and more effective during inter-drought periods. If vulnerable fish stocks and restored habitats are not materially improved between droughts, they are at risk of failing during the next drought.
  8. Salmon hatcheries mostly help to support commercial fisheries, while harming the gene pool of wild stocks, reducing their ability to adapt to changing conditions. This conflict is exacerbated during droughts. More research and a re-thinking of hatchery management is required to separate the needs of competing interests in order to preserve California’s declining salmon heritage, which becomes more vulnerable with each drought.
  9. Climate Change. Preparations must be made for the new California climate: hotter, less snowpack, and with more variable and extreme precipitation. A shift to groundwater storage reliance is taking place and may be helpful in the long term. This will affect the timing and volume of water transport in the Delta, and management responses to emerging stressors.

California’s 2012-2016 drought was practice for future climate change events. The whiplash events of drought followed by flood (e.g., 2017 water year) are unlikely to remain exceptional. In the past century, each drought has brought improvements in water systems and drought management, but at a steep price to environmental conditions in the Delta and its watershed. The shifting climate will exacerbate this trend. Relative to economic, cultural and environmental losses, organized science is cheap. Investing in research can make policy discussions and water investment more effective. A proactive organized campaign to understand and anticipate the changing impact of drought on the Delta and California will help mediate future conflicts and preserve California’s rich natural resources.

Further Reading

Dettinger M, Anderson J, Anderson M, Brown LR, Cayan D, Maurer E. 2016. Climate Change and the Delta. San Franc Estuary Watershed Sci. 14(3). [accessed 2017 Feb 2]. http://escholarship.org/uc/item/2r71j15r.

Durand JR, Bombardelli F, Fleenor WE, Henneberry Y, Herman J, Jeffres C, Leinfelder–Miles M, Lund JR, Lusardi R, Manfree AD, et al. 2020. Drought and the Sacramento-San Joaquin Delta, 2012–2016: Environmental Review and Lessons. San Franc Estuary Watershed Sci. 18(2). doi:10.15447/sfews.2020v18iss2art2. [accessed 2020 Jul 17]. https://escholarship.org/uc/item/6hq949t6.

Lund J, Medellin-Azuara J, Durand J, Stone K. 2018. Lessons from California’s 2012–2016 Drought. J Water Resour Plan Manag. 144(10):04018067. doi:10.1061/(ASCE)WR.1943-5452.0000984.

Mount J, Gray B, Chappelle C, Gartrell G, Grantham T, Moyle P, Seavy N, Szeptycki L. 2017. Managing California’s Freshwater Ecosystems: Lessons from the 2012-16 Drought. San Francisco, CA: PPIC.

Williams AP, Cook ER, Smerdon JE, Cook BI, Abatzoglou JT, Bolles K, Baek SH, Badger AM, Livneh B. 2020. Large contribution from anthropogenic warming to an emerging North American megadrought. Science. 368(6488):314–318. doi:10.1126/science.aaz9600.

The authors participated in this review of Delta management and science during California’s 2012-2016 drought, from a variety of institutions including UC Davis, UC Cooperative Extension, UC Merced, and the Delta Stewardship Council Science Program (which also provided funding).  We thank the many agency staff and stakeholders who participated in this process.


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106 Years of Water Supply Reliability

by Jay Lund

Water supply reliability is a major policy and management goal in California, and in the rest of the world, today and since the beginning of time.  The goals of reliable water supplies have grown from supporting human health, to supporting economic prosperity, to supporting healthy ecosystems, even when these goals conflict.

Since ancient times, water supply planning, engineering, and operations have sought to provide reliable water supplies.  But until 106 years ago, there was little sophistication on exactly how reliable a water supply would be or should be.

Today, water uses have grown and diversified, and sometimes conflict when water availability is insufficient for all uses.   Water availability will always be limited, despite infrastructure investments, and often will diminish or become more expensive with climate change and evolving environmental and public health standards.

However, perfect reliability is never possible, and high reliability often incurs high economic or environmental costs.  This has long been the dilemma in California.  How do we balance reliability, the costs of improving reliability, and the water shortage costs of unreliability?

Allen Hazen’s 1914 paper established a direction for solving this balancing problem.  His paper, “Storage to Be Provided in Impounding Reservoirs for Municipal Water Supply,” assembled streamflow data for more than a dozen water supplies and examined their reliability for a range of water use levels and a range of reservoir sizes.  These calculations were done by hand.

Realizing that these streamflow records were short, he further fit these reliability results onto “probability paper” (which he invented) to better estimate reliabilities for different extremes, configurations, and demands.

For water wonks with technical or modeling interests, Hazen’s paper remains well worth reading.  Few papers about delivery reliability today thoughtfully synthesize such breadth and detail.  Some of the paper’s main lessons remain relevant for water policy and management:

  • No water supply can be completely reliable (from an engineer or manager’s perspective).
  • Higher reliability requires greater infrastructure costs, with extreme reliabilities incurring extremely large infrastructure and costs.
  • Seasonal and over-year water storage should be considered quite differently. Seasonal storage of water in reservoirs requires less storage capacity per unit of reliable delivery.  Storing water for over-year droughts requires proportionally more storage capacity and costs.  “With a larger reservoir, there is some further gain with increasing size, but in a diminishing ratio.”
  • High levels of reliable supply require larger reservoirs, which are costly and will often take years to refill.
  • Even an infinite reservoir size cannot reliably deliver more than a reservoir’s average annual inflow.
  • Regions with more variable hydrology require greater water storage capacity to supply the same reliability, all else being equal.
  • Climate change is likely, but is hard to estimate. There also seem to be longer-term cycles in runoff records, which are difficult to characterize and predict.
  • Quantifying water shortage amounts is important. Probability distributions of shortage can be more useful than the mere probability of a shortage.  However, probability distributions of shortages are harder to estimate, as shortages are usually rare events.
  • Water reliability analysis is inherently approximate, and it is not worthwhile to overly refine data. “In all hydraulic data the probable error of measurement is considerable. There is, therefore, no justification for the application of extreme refinements in methods of calculation.” Evaporation estimates and data are “less adequate than could be desired.  Nonetheless, some approximations can be reached.”  Longer flow records reduce uncertainty, but do not eliminate it.  Even averages have errors. However, probable errors in such estimates can be quantified.
  • The natural storage in lakes and sandy stream and lake banks can only be approximated, but can “have a great influence on the required storage, especially at relatively low draft [withdrawal] rates. …”.
  • Modeling with monthly flows and operations is somewhat less accurate than daily flows, and tends to under-predict storage needs for a given reliability and other conditions. Weekly time steps correct most of this underestimation.
  • Balancing the cost of improving supplies against shortage costs is needed. Reducing water use or adopting other water supplies can be less expensive than expanding reservoirs to increase water storage, especially for infrequent droughts.
  • Sometimes hedging reservoir releases, to create more frequent small shortages, can be less damaging overall than accumulating a smaller number of large shortages instead.
  • Public displeasure with large drought shortages can lead to infrastructure overinvestment. And the public seeing water spilling from full reservoirs in a few years can encourage the public to think that a supply is not being used to its reasonable limit.
  • Hazen extensively discussed limitations of his methods and findings, and estimated and discussed probable errors in his findings. As he summarized, “frank recognition of the large probable errors in many of the results cannot fail to be advantageous.”

Much of today’s work on water supply reliability would advance to reflect some of the methods and thinking from 1914.

Allen Hazen was a founder of modern urban water supply.  Many aspects of urban water systems today date back to him and the State of Massachusetts’ Lawrence Experiment Station in the late 1800s. This was where Hazen and colleagues worked on fundamentals of water filtration, later expanding as a consulting engineer to fundamentals of pipe network water distribution, reservoir sizing, water metering, utility finance, and overall integration of urban water systems.

We all drink water (mostly reliably) based on his work.  Many of his insights and approaches to water problems remain useful today.

Read old to stay sharp.

Further reading

Hazen, A. (1914), “Storage to be provided in impounding reservoirs for municipal water supply,” Transactions of the American Society of Civil Engineers, Vol. 77, December, pp. 1542-1669.

Hazen, A. (1909 and 1914), Clean Water and How to Get It, New York, J. Wiley & Sons, 252 pp.

Hirsch, R.M. (1978), Risk Analysis for a Water-Supply System – Occoquan Reservoir, Fairfax and Prince Williams Counties, Virginia, Open File Report 78-452, U.S. Geologic Survey, Reston, VA, also in Hydrologic Science Bulletin, Vol. 23, No. 4, pp. 475-505.

Klemes, V. (1987), “One Hundred Years of Applied Storage Reservoir Theory,” Water Resources Management, Vol 1 , pp. 159-175.

Jay Lund is a Professor of Civil and Environmental Engineering at the University of California – Davis.  (Today is the 90th anniversary of Alan Hazen’s death.)

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Summer Reading in the Time of Covid 19

by Peter B. Moyle

Tired of reading about the constant haggling over California water? Or of binge-watching old TV shows? Or, worse, watching the news as the Covid 19 virus spreads in our free country? For relief, I recommend two entertaining yet somewhat off-beat books, reviewed here. The books are very different but both involve fish (if indirectly) and both have central characters (an academic and a thief) you may not like at the end. Both also feature museum collections, the first of fish, the second of birds.

Do Fish Exist?

David Starr Jordan (1851-1931) was a great American ichthyologist and world renowned scientist and educator. Woodcut by Chester Woodhull, ca. 1950.

LuLu Miller’s Why Fish Don’t Exist: A Story of Loss, Love, and the Hidden Order of Life (2020, 195 pp) is a ‘good read’, but the book is more about the latter half of the title than the former. The book follows Miller’s search for order and meaning in a universe where Chaos will eventually win out, no matter what. She focuses in good part on David Starr Jordan, seeing him initially as a person who had an amazingly positive view of life, bouncing back quickly from tragedies (such as the smashing of hundreds of bottles of pickled fish that he had collected over decades, by the San Francisco Earthquake of 1906). Jordan saw order in the universe through his describing and classifying of thousands of fish species. Miller read his entire massive autobiography (Days of a Man)1 to try to understand him and explored his other voluminous writings as well. In his day, Jordan was perhaps the best-known scientist in the USA, if not the world, and a great popularizer of the importance of science.

Miller, however, discovers he was likely involved in a murder to protect his funding and, worse, was a leader in the terrible eugenics movement in the USA1. His view of an orderly universe with Man as the pinnacle of evolution, led to severely flawed reasoning about “unfit” humans and the need to stop them from reproducing. Miller twines her life around Jordan’s story and resolves her own inner turmoil, by and large. At the end, she finds love and order in her personal universe, without fish.

The main title is intriguing and provides an excuse for pleasant meandering of her thoughts. The following discussion of that title could be regarded as a spoiler (but it is not, really). One way that fish don’t exist is through the philosophic idea that a fish species does not exist unless we humans give it a name, so it is part of human consciousness. Miller is basically bemused by this idea. Another way is more academic. She talks about the modern cladist approach (quantitative, computerized) to classification, which shows that the diverse evolutionary lineages that we lump together as ‘fish’ don’t have a common origin2: lampreys, hagfish, sharks, lungfishes, bony fishes. The cladistic approach makes terrestrial vertebrates (e.g., us) a subset of the Osteichthyes, the main lineage of bony fishes that includes most of the 30,000 or so fish species.  Therefore, she opines, fish is not a useful or accurate term. Miller is not a biologist herself and is mildly annoyed by the fact that the fish biologists with whom she talked just accept the problem as not being worth fighting over. Thus, in my text book, I call terrestrial vertebrates “aberrant bony fishes that decided to leave the water and invade the land.” I also say, “Humans are not the pinnacle of evolutionary progress but only an aberrant side branch of fish evolution.” Knowing this, you may want to go and seek your inner fish3.

Still, Miller’s book is worth reading if you are looking for Darwin’s ‘grandeur in this view of life’, want to learn about David Starr Jordan, or just enjoy some good stories about life and love. The book also has curious scratchboard illustrations by Kate Samworth, most featuring Jordan and his mustachios as a fish.

Flies without Fish

Jock Scott salmon fly by Timo Kontio (FlyTying Archive).

Kirk Wallace Johnson’s The Feather Thief: Beauty, Obsession, and the Natural History Heist of the Century (2018, 308 pages) is not about fish or water. Its relationship to both is weak, via fly fishing and the tying of artificial flies that are part of the fly-fishing culture. Even here, the tie-in is tenuous because it centers around artificial salmon flies that were developed in Victorian England. These colorful flies have become valuable collector’s items as art objects and are largely tied today by people who do not engage in angling. Their flies have experienced neither water nor fish. The flies are fairly large, around 3-5 cm, and require small pieces of multiple colorful feathers to be tied together. For such a fly to be genuine, the feathers have to come from wild birds with spectacularly colored feathers, such as birds of paradise. In the community of Victorian salmon fly tiers, such feathers today sell for hundreds of dollars. Dyed chicken feathers will not do.

This book focuses on the theft, by a young champion tier of these flies, of dozens of bird specimens from the British Museum of Natural History. The Museum houses the largest collection of birds in the world, including specimens collected in the 19th century by great naturalists such as Charles Russell Wallace. In just one break-in, the thief took 299 specimens of some of the most beautiful birds in the world in order the pluck feathers from them. The book is the author’s attempt to understand the crime and the criminal, with diversions into subjects such as the deprivations that Wallace experienced in order to collect skins that were stolen and the devastation of bird populations caused by collection of plumes for ladies hats. It reads like a good mystery novel in many respects. The feather thief does get caught eventually but the author’s digging found that crime pays, or at least this crime did. The book does suggest that better security is needed for natural history collections, perhaps even for fish collections.


1 I have a copy, inherited from my father.  It’s only 906 pages long. I have not read it.

2 Miller points out that eugenics has not gone away; forced sterilization laws are still on the books in many states, ignored but not repealed.  When I was an undergrad in the 1960s, the required genetics course I took was called “Genetics and Eugenics” although I don’t recall the prof saying anything about eugenics…

3 Of course, all organisms have a common origin if you go back far enough in time.  What she really means is that cladistics does not result in single category “fish” that is equivalent to amphibians, reptiles, birds, and mammals.

4 See Neil Shubin’s 2009 book, Your Inner Fish: A Journey in to the 3.5 billion-year History of the Human Body.

Further Reading


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Can we talk? New nationwide flood maps provide opportunities for dialogue

by Kathleen Schaefer and Brett F. Sanders

Why Dialogue Matters

For fifty years, Flood Insurance Rate Maps (FIRMs) have unintentionally stifled conversations of flood risk. They have encouraged property-owners and governments at all levels to dwell on map details for one static event, rather than flood risks for a range of events under changing conditions (Soden et al. 2017). Now, First Street Foundation[1] has released a new tool that can change how these conversations develop: Flood Factor, a publicly available online resource to help people understand flood risk for an individual property, area, or region.

For each property parcel, several indicators about flooding are provided by Flood Factor including information about past floods, past flood claims, present-day flood risk, and future risks. This makes it possible to learn if a home has flooded from major recent events, is currently at risk, and how that risk changes over time. This follows previous efforts to bring detailed information on sea level rise into coastal community planning (e.g., Fu et al. 2017).  Importantly, the tool presents an opportunity for fresh dialogue about flooding, including what’s at risk and ways to manage it. There is growing interest in having these types of conversations across the U.S. (National Academies 2019, Sanders et al. 2020).

To frame the timeliness of new flood risk information for dialogue, we can go back to 1968 when Congress passed the National Flood Insurance Act. Community participation in the National Flood Insurance Program (NFIP) and homeowner purchase of a flood policy were initially voluntary (Burby 2001; Horn and Brown, 2017), and the NFIP gave homeowners a more affordable option for insurance than what was available from the private sector (Burby 2001). To determine who would quality, a 1% annual chance risk (or 100-year return period) was selected as the standard, and Flood Insurance Rate Maps (FIRMs) were created to delineate flood hazard zones where properties met the standard. Moreover, community-level dialogue about flooding, and how to manage risks, was part of the plan. As a partnership between federal, state and local government, the NFIP required that communities take responsibility for managing floodplains to reduce the damages of floods and taxpayer liabilities.

But in the ensuing years, major disasters prompted Congress to change the NFIP to a mandatory program. This unintentionally derailed productive conversations about flooding. FIRMs, with the single “in-out” 100-year flood zone boundary, became a battle map. If FEMA announced that it was going to initiate a new study, community leaders would vow to fight the new maps. The contentious nature of the maps made flood risk something no one wanted talk about or pay for. Interest and funding for updating the maps also declined. Today, engineering studies of flood hazards for almost half of California’s communities are over 20 years old. FEMA has designated less than 23% of California’s mapped river miles as ‘valid.’ And, less than 30,000 miles of the State’s estimated 180,000 stream miles have been mapped.

FEMA has worked to develop a more community-friendly mapping process called Risk MAP, and it has shown promise for improving dialogue and deliberations about flooding. However, nationwide implementation of Risk MAP appears cost prohibitive. A study by the California Department of Water Resources (DWR), funded by FEMA, found that implementing the Risk MAP process in California alone would cost $445 million and concluded that much of California would never again see a new FIRM (CA DWR 2013). Indeed, what California and all of the U.S. now have is Flood Factor.

A sample set of depth maps from Flood Factor is shown below in Fig. 1, including a depiction of a past flood, the present-day 500-year return period event, and a future 500-year return period event. Multiple depictions about flooding are important for meeting needs of different end-users of hazard maps (Sanders et al. 2020), and for encouraging end-users of flood hazard information to “wrestle with uncertainty” about flooding (Soden et al. 2017). Whether the resulting dialogue will be productive is unclear.

Flood 1

Fig 1. Sample of past, current and future flood risk for Toledo, Ohio


FloodRISE reveals keys to productive dialogue

Fostering productive dialogue about a societal problem like flooding is challenging. Researchers at UC Irvine tested the value of more detailed flood data, and more intuitive visualizations, in the context of a community-based approach to flood resilience through a program called FloodRISE funded by the National Science Foundation. Working in three coastal sites with different flood hazards (coastal, fluvial and pluvial) and contrasting socio-economic conditions, research showed the importance of fine-resolution data (resolving individual streets and land parcels) for increasing awareness about flooding and building a shared awareness of flooding across subgroups in the community (Cheung et al. 2016, Houston et al. 2019). Research also showed the importance of inclusive and iterative community engagement, which promoted trust, heightened interests, and improved flood model accuracy through input of local knowledge (Luke et al. 2017, Sanders et al. 2020, Goodrich et al. 2020). Iterative community engagement allowed researchers to tailor flooding scenarios, mapped variables and contextual information to the needs and preferences of local end-users including planners, residents, public works managers, developers, natural resource managers, emergency managers, and non-governmental organizations. Hence, a participatory research approach was critical to building trust (Goodrich et al. 2020) and making flood maps that end-users found useful (Luke et al. 2017, Sanders et al. 2020). Examples are shown in Fig.2.

The FloodRISE project also showed that is possible to change power structures that develop around control over the flood mapping process. Dialogue between researchers and diverse groups of end-users triggered “what if” scenarios related to the management and operation of watersheds and flood infrastructure, which were then modeled and mapped (Luke et al. 2017, Goodrich et al. 2020). Historically, such analyses have only been accessible to those with financial resources to hire technical consultants, which excludes many from processes to plan for and respond to flooding.

Flood 2

Fig. 2 Examples of flood hazard maps for Newport Bay including: (left) flood depth for a historical event including photos of flooding; (middle) year 2015 chance of flooding; and (right) year 2035 flood depth corresponding to the 1% annual chance event.  The flood depth scale, dimensioned by the average human body size, is an example of co-production by researchers and end-users.

A contrasting experience with detailed flood maps was reported in Florida, where researchers sought to better understand how information on flooding affected attitudes and opinions about climate change and sea level rise (Palm and Bolsen, 2020). Here, researchers reported that those who viewed detailed flood maps showing future flooding from sea level rise were less likely to believe that climate change was occurring and responsible for increasing coastal flooding—a response linked to political party affiliation. This aligns with a general U.S. trend of polarized views on climate issues and mistrust of scientists around party affiliation (Pew Research Center, 2016).

First Street Foundation Brings Detailed Data to the U.S.

The contrasting California and Florida experiences using detailed flood maps to engage communities in conversations about flooding point to both dangers and opportunities on the horizon for flood management. One danger is that people will not be familiar with the First Street Foundation, and there will be insufficient trust for productive dialogue. Furthermore, mapping errors could undermine trust and perceptions of risk (Cheung et al. 2016, Houston et al. 2019).  Just as FEMA flood maps are prone to errors due to various reasons including data quality, rules about what gets mapped (Wing et al. 2018) and the impacts of political influence (Burby 2006), there will be errors in Flood Factor maps based on limited local knowledge and uncertain models and data. For example, a comparison of FloodRISE and Flood Factor depictions of the 1% annual chance flood zone for Newport Beach, California, where FloodRISE benefitted from extensive local data and knowledge, showed significant differences. Furthermore, most communities do not have a mechanism to dialogue with experts about flood risk, which is critical for building actionable knowledge (Lemos et al. 2018, Goodrich et al. 2020).

On the other hand, major opportunities stem from the potential to engage many more people across the U.S. in contemplating the possibility of flooding, and wresting with uncertainty about what might happen. Furthermore, Flood Factor can not only support national conversations about flooding by policy makers, but serve as a shared reference point for community- and regional-level discussions nationwide. Finally, the form of Flood Factor data, intuitive maps of flood depth for different events, is a much-needed departure from FEMA’s cryptic flood hazard mapping conventions (e.g., Zones AR, X and VE) and terminology (e.g., “floodway”, “special flood hazard area”). These changes are desperately needed so community conversations about flooding focus less on mapping conventions and more about the consequences of flooding and what can be done about it (Sanders et al. 2020).

Kathleen Schaefer is a Ph.D. candidate in Civil and Environmental Engineering at the University of California, Davis. Kathleen’s research is focused on examining community-based alternatives to the NFIP. Brett Sanders, Ph.D. is a Professor of Civil and Environmental Engineering at University of California, Irvine. Dr. Sanders served as Principal Investigator of the the FloodRISE Project, promoting resilience to coastal flooding in Southern California, and leads the Flooding and Poverty Division of the UCI Blum Center for Poverty Alleviation.

Further reading

Burby, R.J., 2001. Flood insurance and floodplain management: the US experience. Global Environmental Change Part B: Environmental Hazards, 3(3), pp.111-122.

Burby, R.J., 2006. Hurricane Katrina and the paradoxes of government disaster policy: Bringing about wise governmental decisions for hazardous areasThe annals of the American academy of political and social science604(1), pp.171-191.

CA DWR. 2013. California Deployment and Mapping Master Plan (Draft). Prepared under Mapping Activity No. 3 executed in 2010 by Atkins. Sacramento, CA: CA Department of Water Resources.

Fu, X., Gomaa, M., Deng, Y. and Peng, Z.R., 2017. Adaptation planning for sea level rise: a study of US coastal citiesJournal of environmental planning and management60(2), pp.249-265.

Goodrich, K.A., Basolo, V., Feldman, D.L., Matthew, R.A., Schubert, J.E., Luke, A., Eguiarte, A., Boudreau, D., Serrano, K., Reyes, A.S. and Contreras, S., 2020. Addressing Pluvial Flash Flooding through Community-Based Collaborative Research in Tijuana, Mexico. Water, 12(5), p.1257.

Horn, Diane P., and Jared T. Brown.  2017. Introduction to the national flood insurance program (nfip). Congressional Research Service. Washington, D.C.

Houston, D., Cheung, W., Basolo, V., Feldman, D., Matthew, R., Sanders, B.F., Karlin, B., Schubert, J.E., Goodrich, K.A., Contreras, S. and Luke, A., 2019. The influence of hazard maps and trust of flood controls on coastal flood spatial awareness and risk perception. Environment and Behavior, 51(4), pp.347-375.

Lemos, M.C., Arnott, J.C., Ardoin, N.M., Baja, K., Bednarek, A.T., Dewulf, A., Fieseler, C., Goodrich, K.A., Jagannathan, K., Klenk, N. and Mach, K.J., 2018. To co-produce or not to co-produce. Nature Sustainability, 1(12), pp.722-724.

Luke, A., Sanders, B.F., Goodrich, K.A., Feldman, D.L., Boudreau, D., Eguiarte, A., Serrano, K., Reyes, A., Schubert, J.E., AghaKouchak, A. and Basolo, V., 2018. Going beyond the flood insurance rate map: insights from flood hazard map co-production. Natural Hazards and Earth System Sciences, 18(4), pp.1097-1120.

National Academies of Sciences, Engineering, and Medicine, 2019. Framing the challenge of urban flooding in the United States. Washington, DC: The National Academies Press.

Palm, R. and Bolsen, T., 2020. Results from South Florida Experiment. In Climate Change and Sea Level Rise in South Florida (pp. 81-92). Springer, Cham.

Pew Research Center, 2016. The politics of Climate. https://www.pewresearch.org/science/2016/10/04/the-politics-of-climate/

Sanders, B.F., Schubert, J.E., Goodrich, K.A., Houston, D., Feldman, D.L., Basolo, V., Luke, A., Boudreau, D., Karlin, B., Cheung, W. and Contreras, S., 2020. Collaborative modeling with fine‐resolution data enhances flood awareness, minimizes differences in flood perception, and produces actionable flood maps. Earth’s Future, 8(1), p.e2019EF001391.

Soden, Robert, Leah Sprain, and Leysia Palen. “Thin Grey Lines: Confrontations With Risk on Colorado’s Front Range.” In CHI, pp. 2042-2053. 2017.

Wing, O.E., Bates, P.D., Smith, A.M., Sampson, C.C., Johnson, K.A., Fargione, J. and Morefield, P., 2018. Estimates of present and future flood risk in the conterminous United States. Environmental Research Letters, 13(3), p.034023.

[1] The data was produced by researchers and hydrologists from First Street Foundation; Columbia University; Fathom; George Mason University; Massachusetts Institute of Technology; Rhodium Group; Rutgers University; University of California, Berkeley; and University of Bristol.

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Initial Sampling of the Carp-DEUM Project

By Kim Luke, John Durand, Rachel McConnell, Aaron Sturtevant, Nina Suzuki, Andrew L. Rypel

This spring, the Carp-Dependent Urgent Management (Carp-DEUM) Project began its first round of sampling in the UC Davis Arboretum before the Covid-19 lockdown. The project has two planned phases; a population estimate of common carp (and other arboretum fishes) in the Arboretum and a subsequent carp exclosure experiment. We want to know if removing carp can improve water quality and reduce harmful algal blooms, HABs. Carp are widely known to bioturbate sediments where previously deposited nutrients like phosphorus are bound (see YouTube video below). Re-suspension of phosphorus by carp leads to HABs, creating an interesting link between fish and human health. At the same time, this exercise also provides an opportunity to evaluate the unique fish community and limnological conditions within the Arboretum. 

Challenges in the Arboretum 

The Arboretum is the former pathway of Putah Creek, before the creek was diverted to the south of town in 1871 as part of bringing the railroad through. The channel has been heavily re-shaped by humans, making it a challenging place to sample. Natural banks have been replaced by concrete banks with steep, landscaped sides. However, a series of weirs on the eastern end of the Arboretum allow for periodic draining of parts of the Arboretum, which in turn present opportunities for studying fish. During spring this year, when the weirs were open, we prevented fish from escaping sampling sections with a block net, drained the water to a wade-able height and used a beach seine to sample every possible fish in the three middle sections (Figures 1 and 2). Of the five available sections, the three middle were chosen for initial sampling due to their relatively straight and narrow form.

Fig. 1. Undergrads Aaron and Kim setting up the block net. Photo: Nina Suzuki

Seining Methods

Once the sections were drained and the water level lowered, we began seining. A beach seine is a long net pulled manually by two poles (or brailers) on each end. The top of the net has a line of floats and the bottom a line of weights. We pulled the net along the channel from the lower weir to the upper weir, and rolled the seine up until it was flush against the concrete bank (because there is no beach to land it on). We then lifted the net from the water, and transferred the live fish into a large aerated container of water. We seined the lowest section just once because of the quantity of detritus and other debris on the bottom. The middle section was seined four times and the upper section five times in an effort to catch most of the fish present.

Fig 2. Undergrads Aaron and Kim seining for fishes. Photo: Gregory Urquiaga

What We Found

We found an abundance and diversity of fish in these sections, as well as turtles, crawfish–and even a cash register! The predominant fish species found in these sites were 1058 Fathead Minnow (Pimephales promelas), and 743 Black Bullhead (Ameiurus melas). We also seined 358 Mosquitofish (Gambusia affinis), 149 Green Sunfish (Lepomis cyanellus), and 263 native Sacramento Blackfish (Orthodon microlepidotus) (Figures 4). A few carp were found in two of the three sections, and a goldfish was found as well. We found fewer carp than anticipated, though we still suspect they are an abundant fish, as they are easily spotted in many other reaches of the Arboretum. The weir sections might make it difficult for carp to pass upstream, limiting the accessibility of carp to these sections compared to lower parts of the Arboretum where more carp are typically seen.

Fig. 3. Undergrad Rachel with a Carp. Photo: Gregory Urquiaga

One particularly interesting species found in abundance was the Sacramento Blackfish. Like Common Carp, this species also belongs to the cyprinid family, but unlike carp, they’re native to the Sacramento and San Joaquin watersheds. Sacramento Blackfish prefer the warm, turbid water of off-channel floodplain habitats that once dominated the Sacramento Valley in spring and summer. As adults, they eat algae and organic matter floating in the water–widely available in the Arboretum in summer. Given its murky waters full of algae, the Arboretum is an ideal habitat for Sacramento Blackfish. While preventing HAB’s and improving water quality is our goal, we will need to consider how removal of carp could affect the habitat of a native fish with a declining population.

Fig. 4. Species abundance data from initial fish sampling in the Arboretum waterway. Fish graphics from
https://bit.ly/2AavY8Q; https://bit.ly/3dHp8oU; https://bit.ly/3dBgTuI; https://bit.ly/3dAagJa; https://bit.ly/2YDiT1o; https://bit.ly/2ZgoJVr

What’s Next?

Based upon our preliminary work, we intend to sample other sections of the Arboretum, potentially with different methods. The larger, more open areas in the lower west end of the Arboretum appear to host many more carp, which can often be seen by people above water cruising, rooting and feeding. Because it may be even more difficult to sample these sections with a seine, we will use fyke nets, which are a kind of modified fish trap made from netting to conduct mark-and-recapture experiments. Once we have a better estimate on the total carp population and biomass, we will move on to the second part of the project, installing exclosures, removing carp from exclosures, and monitoring the change in vegetation and water quality in the exclosures and control plots. Given the shutdown in response to the Covid-19 pandemic, further sampling is postponed for now. We will resume once we can do so safely. In the meantime, the western end of the Arboretum can be a safe place for exercise, fresh air and carp-viewing during this time. If you visit the Arboretum, be sure to wear a face mask, and maintain a safe social distance from other human visitors of at least 6 feet.

Kim Luke is a junior specialist at the Center for Watershed Sciences at the University of California, Davis. John Durand is a Research Scientist at the Center for Watershed Sciences. Rachel McConnell and Aaron Sturtevant are graduating from UC Davis and are researchers at the Center for Watershed Sciences community. Nina Suzuki is the Waterway Steward at the UC Davis Arboretum and Public Garden. Andrew Rypel is an associate professor of fish ecology and the Peter Moyle & California Trout Chair at UC Davis and an associate director at the Center for Watershed Sciences.

Further Reading


Lake Wingra carp removal – https://lter.limnology.wisc.edu/research/research_highlight/water-clarity-responses-carp-reduction-shallow-eutrophic-lake-wingra

Lake Kegonsa carp removal – https://bit.ly/2YFRPhW

The “Carp Cannon” – https://kstp.com/news/u-of-m-researchers-experiment-with-carp-cannon-to-stop-spread-of-invasive-fish/5370984/

Carp Removal Studies

Lathrop, R. C., D. S. Liebl, and K. Welke. 2013. Carp removal to increase water clarity in shallow eutrophic Lake Wingra. Lakeline 33:23-30.

Carp and Macrophytes

Miller, S., and T. Crowl. 2006. Effects of common carp (Cyprinus carpio) on macrophytes and invertebrate communities in a shallow lake. Freshwater Biology 51:85-94.

Carp Effects on Water Quality

Bajer, P. G., and P. W. Sorensen. 2015. Effects of common carp on phosphorus concentrations, water clarity, and vegetation density: a whole system experiment in a thermally stratified lake. Hydrobiologia 746:303-311. 

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People, Agriculture, and Water in California

by Jay Lund


Farmworker housing in Corcoran, CA, 1940

Agriculture is California’s predominant use of managed water.  Agriculture and water together are a foundation for California’s rural economy.  Although most agriculture is economically-motivated and commercially-organized, the sociology and anthropology of agriculture and agricultural labor are basic for the well-being of millions of people, and the success and failure of rural, agricultural, and water and environmental policies.

The economic, ethnic, and class disparities and opportunity inequalities in urban life are urgent problems today.  Similar problems continue to exist in the structure of rural communities.  These rural problems often are more dire and difficult because the lower densities of rural settlement make these problems harder to observe, bring greater difficulties for organization, information, and logistics, and increase per-capita expenses for actions that provide services (water, education, transportation, housing, and all manner of human services).  The anthropologist Walter Goldschmidt observed these difficulties in California’s San Joaquin Valley in the 1940s (as John Steinbeck did in the 1930s).

Most serious social scientists and policy wonks of California agriculture (and agriculture in general) have read Walter Goldschmidt’s As You Sow (1947).  Those who haven’t should.

Despite decades of subsequent research, much of this work could be written and read insightfully today, and it retains much influence, as seen in Mark Arax’s recent history of California’s water development (2019).

Some, of many, points made in Goldschmidt’s book include:

  • History, expectations, and economic structure have implications for local social structure and the experience and opportunities of people individually and as social groups. The San Joaquin Valley’s social structures arose and arise from a history of demographic, economic, and social transitions built around migrations, farming, and perceived economic opportunities.  Goldschmidt discusses how these transitions often involved efforts to limit opportunities for some groups, particularly individuals and groups providing farm labor.
  • The book is a nice example of a fairly classical anthropological/ethnographic approach to studying social structure and public policy issues, showing how social scientists have long produced insightful results for policy problems, in this case on social, economic, and policy implications of modernization in agriculture and the urbanization of agriculture and rural life. (Feel free to comment on this post with citations and links to additional great examples – a few appear under further reading.)
  • The original presentation of what became the “Goldschmidt hypothesis,” that areas dominated by family farms tend to have more desirable socioeconomic conditions than industrial farming areas. This idea has been both supported and not supported by many more recent studies (cited under further readings), and might be less relevant today as remaining commercial family farms have grown in industrial scale since the 1940s.
  • The importance of effective local social and governmental organization and expectations for providing good schools, social services (human services, police, etc.) and infrastructure services (water, sewer, transportation, housing, energy, and solid waste). This applies for everyone, everywhere and at all times, I think.
  • Fundamental objectives of policy – these seem eternal and relate to more than just rural and agricultural policy (p. 254): “Three fundamental principles must underlie any constructive farm policy consistent with American democratic tradition:
    • The full utilization of American productive capacity to insure the welfare of all the people and the strength of our nation;
    • The preservation of our national resources to insure that maximum production can continue without loss from earlier exploitation of the land;
    • The promotion of equity and opportunity for those whose life work is devoted to the production of agricultural commodities.”
  • One footnote I enjoyed were references to the scholarly work of Clark Kerr on farm labor and policy in the 1930s. Clark Kerr went on to oversee the progressive transformation of the University of California in the 1960s as UC President.

This is another great book on California, agriculture, and water (one of many).  It nicely focuses on people, and some of the most economically and socially underprivileged people in California, then and now.  These places, and their like, still exist with social and economic structures that affect human health, well-being, and water management (Ramsey 2020).  Struggles to better achieve the universal political and economic objectives summarized by Goldschmidt in 1947 continue.

Considering people in agriculture is among the hardest and most central issues as California works to adapt agriculture to reduce groundwater overdraft and contamination, manage the Delta more sustainably, improve rural water services, protect ecosystem health, and improve rural life and opportunities.

As I read recently, “Read old to stay sharp.”  And then read some more.

Jay Lund is a Professor of Civil and Environmental Engineering at the University of California – Davis.  His now-ancient MA thesis at the University of Washington, Seattle, was an ethnographic study of urban liveaboards.

Further Reading

Arax, M. The Dreamt Land: Chasing Water and Dust Across California, Penguin Random House Books, 2019.

Goldschmidt, Walter R. (1947). As You Sow: Three Studies in the Social Consequences of Agribusiness. Montclair, N.J: Allanheld, Osmun and Co. Publishers, Inc.


Hoggart, K. (1987) Income Distributions, Labour Market Sectors and the Goldschmidt Hypothesis: the Nonmetropolitan United States in 1970 and 1980,” Journal of Rural Studies. Vol. 3. So. 3. pp. 31-245.

Peters, D. 2002. Revisiting the Goldschmidt Hypothesis: The Effect of Economic Structure on Socioeconomic Conditions in the Rural Midwest. P-0702-1. MERIC, Missouri Department of Economic Development.

Works by Michael Eissinger: http://meissinger.com/publications–papers.html

Ramsey, A.R. (2020), “The Great Divide: California communities battle for rights to water,” Fresno Bee, 5 June, https://www.fresnobee.com/news/local/water-and-drought/article243237701.html


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What’s the dam problem with deadbeat dams?

by Andrew L. Rypel, Christine A. Parisek, Jay Lund, Ann Willis, Peter B. Moyle, Sarah Yarnell, Karrigan Börk

Damming rivers was once a staple of public works and a signal of technological and scientific progress. Even today, dams underpin much of California’s public safety and economy, while having greatly disrupted native ecosystems (Quiñones et al. 2015, Moyle et al. 2017), displaced native peoples (Garrett 2010), and deprived residents of water access when streamflow is transported across basins. California’s dams are aging and many will require expensive reconstruction or rehabilitation. Many dams were built for landscapes, climates and economic purposes that no longer exist. California’s current dams reflect an accumulation of decisions over the past 170 years based on environmental, political, and socio-economic dynamics that have changed, sometimes radically. Former Secretary of the Interior Bruce Babbitt remarked, “Dams are not America’s answer to the pyramids of Egypt… Dams do, in fact, outlive their function. When they do, some should go.

Is California prepared for updating or removing this infrastructure, and what would be the consequences of inaction?

Fig. 1. Transformation of the West through government funded irrigation. From: Donald J. Pisani, To Reclaim a Divided West: Water, Law, and Public Policy, 1848-1902 125 (University of New Mexico Press, 1992)

We examined the National Inventory of Dams (NID) to assess the state of California’s dams. This database is a large data product curated by the US Army Corps of Engineers and contains information on most large dams in the USA (Fig. 2, 3, Table 1). Across the nation there are 91,468 NID dams, with 1,580 in California. Because there are multiple dams on some reservoirs, we estimate a total of 80,101 and 1,444 NID reservoirs in the USA and California, respectively.

Mean age of USA dams is 59 years old; but mean age of California dams is 72 years (Fig. 3). The 25% oldest CA dams are 93 years or older. California’s total reservoir storage capacity behind NID dams is 45 million acre-feet with a total reservoir surface area of 713,146 acres. For comparison, the total surface area of all managed natural lakes in Wisconsin is 943,130 acres, supporting a massive tourism industry (Rypel et al. 2019). Unfortunately, 1,097 (69%) of California NID dams are listed as high or significant hazards to human communities if they fail (Fig. 2, Table 2). These counts greatly underestimate problematic dams. In the USA, there are hundreds of thousands of smaller (often old) dams that fall outside of state and federal lists, and so are not included in the NID. This issue is broader than just dams too – infrastructure of all varieties is aging, representing a growing problem for humans and wildlife (Börk and Rypel 2020).

Fig. 2A. Map of all California dams in the NID.
Fig. 2B. Map of all NID dams in the contiguous USA. In both maps red circles represent dams classified in the NID as “high hazard” (i.e.,the potential for dam failure or facilities mis-operation to result in loss of human life, in addition to lower risk characteristics such as potential for economic and environmental losses). Gray circles represent all other dams.

Fig. 3. Histograms describing characteristics of dams and reservoirs in the USA and California. All data are from the National Inventory of Dams database. All log transformed data are (Log+1) transformations, however mean values in text boxes are non log-transformed values. Year Dam Completed was cropped at >1750 for ease of viewing.

We have already witnessed examples of the high cost of inaction. Recently in Michigan, two dams (Edenville and Sanford) failed and forced the evacuation of 10,000 residents in the midst of the COVID-19 pandemic – essentially a worst case scenario. Extreme rain in the midwest led to historic flooding in the Tittabawasse and Tobacco Rivers. Federal regulators had worried about failures at the Edenville Dam for 30 years due to an undersized spillway (see related news stories 1, 2, 3, 4).

Table 1. Summary statistics on age and storage capacity of dams and reservoirs in the USA and California.

Fig. 4. Oroville’s failing primary spillway during spring 2017. Photo source: wikicommons.org

In California, we recall a near miss when the Oroville Dam spillway failed in early spring 2017. Floods damaged the primary spillway such that the California Department of Water Resources stopped flow over the spillway to better assess damage. Lake levels continued to fill and ultimately overtopped the emergency spillway, triggering unexpected erosion around the emergency spillway and the evacuation of 188,000 residents downstream. An independent forensic report of the Oroville incident highlights several lessons, including the need for periodic review of dam design and performance. Dams in California have failed before and a list of major events can be found here and here. Recent evaluations have indicated that conditions of California dams are below average, with one reporting a statewide grade of “C-” (Moser and Hart 2018; https://www.infrastructurereportcard.org/state-item/california/).

Table 2. Summary of hazard classifications for USA and California dams based on the NID. The NID defines hazard potentials as: “High” –  dam failure is likely to result in loss of human life. “Significant” – likely no risk to human life, but a likelihood to cause economic and/or environmental losses. “Low” – likely no risk to human life and low anticipated economic and/or environmental losses. “Undetermined” – hazard designation not assigned; here, dams classified as “undetermined” were grouped with dams that had an N/A hazard potential.

Dams also can have catastrophic effects on natural ecosystems, especially in productive and species-rich large rivers (Poff et al. 1997). Dams fragment the hydrologic connectivity of ecosystems, and create massive physical barriers for migratory species, including salmon. American rivers are so extensively fragmented by dams, that Benke (1990) estimated only 42 high quality free-flowing rivers remain in the USA – zero in California. In the Sacramento Valley, abundant spring-run Chinook salmon would once migrate long distances and over-summer high in cold mountain streams. Now, spring-run Chinook salmon are listed under the US Endangered Species Act, largely because of disruptions from dams. In the San Joaquin River, construction of Friant Dam preceded a rapid eradication of spring-run Chinook from this ecosystem. Expensive efforts to reintroduce spring-run Chinook salmon hold promise; but fish are still fundamentally blocked from naturally cold habitats by rim dams. The McCloud River once had all four runs of Chinook salmon, plus steelhead and bull trout. None of these species occur in the McCloud River anymore, and bull trout have gone extinct in California. Helfman (2007) suggested that ~70% of global freshwater fish extinctions can be attributed to “habitat change,” including effects of dams.

Fig. 5. Migratory salmon are strongly and negatively affected by dams. This photo shows the types of habitats that salmon often cannot ascend to in California any longer. “Salmon on spawning beds” by John Cobb 1917 in Pacific Salmon Fisheries. Annual Report to the Secretary of Commerce, 1915-1916, Washington DC. Downloaded from Wikicommons and the Freshwater and Marine Image Bank.

Beyond the catastrophic failures and ecological impacts of individual dams, California’s dams create disastrous outcomes for disadvantaged communities, including Native American Tribes. Tribes along the Klamath have spent years struggling to preserve the river and its sensitive salmon populations. Removing deadbeat dams like the four major dams on the Klamath River along the CA-OR border exemplify the types of projects where removal makes economic sense to dam owners and begins to address damage to indigenous communities of color and aquatic ecosystems. NGOs have long been interested in dam removals like this. However, the slow speed of these removals highlights the complicated details involved in removal. Such experiences suggest efforts addressing aging dams must start early.

The California Division of Safety of Dams (DSOS) has existing responsibilities that include: 1) Performing independent analyses to understand dam and appurtenant structures performance; 2) Overseeing construction to ensure work is being done in accordance with approved plans and specifications; and 3) Inspecting dams on an annual basis to ensure it is safe, performing as intended, and is not developing issues. Roughly 1/3 of these inspections include in-depth instrumentation reviews of the dam surveillance network data. Every state (except GA) has a dam safety program, and the CA program is the largest in the USA. Therefore, the DSOD plays a major role in working with dam owners to identify deficiencies in California. The size of the DSOS program suggests this resource could be leveraged in CA to take a leading role in dam safety. Response to aging dams has been mostly reactive. Studies of dam behavior during earthquakes has been a long focus of research, and such questions are obviously important in California. In a 1977 USGS analysis of dam structural behavior during Earthquakes, half the study systems were in California. Many of the major dam failures in California were triggered by earthquakes.

California is well-positioned to lead in proactively addressing aging dams; however, the window for leadership is likely closing. The challenge will be in developing balanced approaches that prioritize the dams, rivers and people in most need of help (Null et al. 2014). To advance policy on dealing with obsolete dams, we suggest California should:

(1) Form a “California Dams Blue Ribbon Panel”. Given recent experiences in California and nationally, it seems timely for the State of California to take stock and assess the long-term performance of its dam regulation capabilities. Efforts are needed to assist the public, local governments, and dam owners in identifying at-risk dams in need of action. A California dams blue ribbon panel would help develop a framework for decision making that could be applied to dams across the state. The panel’s charge would be to: i) evaluate the state’s existing regulatory framework for evaluating public safety and environmental performance of dams; ii) estimate overall magnitude of current and future dam safety and environmental problems (especially with climate change); iii) recommend improvements to state regulatory capacities and support for owners in terms of dam safety and environmental performance. Panel findings might be published as a white paper for others to use and reference. The panel should have broad representation from multiple stakeholder groups including roles for Native American tribes and other disadvantaged and at-risk communities. Ultimately, a blue ribbon panel and white paper format would produce faster results than a larger task-force style effort, but could lead to a larger effort if necessary.

(2) Develop a structured assessment tool. An objective science-based prioritization framework would be useful. Structured assessments are a class of tools that can more transparently and objectively analyze natural resource management decisions in a careful and organized way (Gregory et al. 2011). Such models are popular in some federal agencies and have already aided decision-making in other areas of CA state government, such as welfare services. A directed action to build such a tool could rapidly aid agencies charged with managing aging dams and scoring restoration projects. Once the tool is available, proposed on-the-ground restoration projects could be scored more transparently. Projects that propose work on high priority dam sites might then be prioritized for funding. Thus restoration projects funded through state bond propositions (e.g., Prop 1 and Prop 68) net the state and its investors the most “bang for their buck”, while simultaneously leveraging science and enhancing transparency and accountability. Improvements to the assessment method could form a way of incorporating new scientific findings or ways of thinking over time.

(3) Revisit existing legal frameworks. Dams sit at the crossroads of state and federal law and so face a complex mess of state and federal laws and regulation. Prominent legal issues will include liability for flooding and for environmental damages associated with dam removal (which will differ between privately and publicly owned dams), environmental reviews mandated under state and federal endangered species and environmental impact laws, and the myriad dam-specific laws. This is an area of active research in environmental law (see here recents legal debates on issues facing dams in the Western USA). Some examples of laws that have legal relevance to the operation and use of dams include the California Fish and & Game Code 5937 – “Water for Fish” (Börk et al. 2012). Additionally, under the authority of the Federal Power Act, the Federal Energy Regulatory Commission (FERC) retains exclusive authority to license non-federal hydropower projects on navigable waterways, federal lands, or areas connected to the interstate electric grid. Opportunities for dealing with deadbeat dams also present themselves during the FERC relicensing process. Indeed this was a critical piece to the removal of the Klamath Dams. Most dams currently face little regulation and receive little attention from policy makers.

(4) Explore reservoirs as novel habitats for declining fishes. Because many California reservoirs contain expansive coldwater habitats, scientists have occasionally suggested reservoirs could be capable of serving as emergency rooms for declining native fishes. Some California reservoirs have developed self-sustaining populations of Chinook salmon (Perales et al. 2015). These populations may be needed as a backup plan in the event a disease or other disturbance afflicts the primary Sacramento River salmon runs. We support this concept and note that some reservoirs and dams may hold hidden value in this regard. Reservoirs successfully managed as novel habitat for native fishes might ultimately be scored higher for dam renovation or repurposing funds.

Every dam is unique and there will be no one-size-fits-all approach. Ultimately dams are owned by entities ranging from the state of California, water agencies and districts, counties, cities, homeowner’s associations, private companies, or private citizens. Hansen et al. 2020 identified that in general dams can be mitigated, renovated, repurposed, or eliminated. In California, dams have been important in controlling water availability, both reducing the frequency of catastrophic floods and making water available for cities and irrigated agriculture in our highly variable Medeterranean climate. They will remain vital in the future, perhaps even more so with anticipated changes in climate. Ultimately, some dams will be fine, some will need to be removed, and some modified. At this point however, an overarching strategy is needed to guide efforts to identify which dams are suited to our uncertain future and which are more risky than worthwhile, then rank them with the best rubric we can devise (e.g..Quiñones et al. 2015). Planning for aging dams is not unlike planning for a pandemic. It seems as though you don’t need it…until you do.

Fig. 6. The upper Klamath River in Oregon was once accessible to salmon migrating from the Pacific Ocean through California. The Klamath dam removals promise to reconnect some of these habitats. Photo by Bob Wick, source Wikicommons.org

Further Reading

ASCE Committee on America’s Infrastructure. 2017. Infrastructure in California. ASCE: Reston, Virginia. https:// www.infrastructurereportcard.org/state-item/california/

Benke, A.C. 1990. A perspective on North America’s vanishing streams. Journal of the North American Benthological Society 9: 77-88.

Börk, K.S., J.F., Krovoza, J.V. Katz and P.B. Moyle. 2012. The rebirth of California Fish & Game Code Section 5937: water for fish. UC Davis Law Review 45: 809-913.

Börk, K., and A.L. Rypel. 2020. Improving infrastructure for wildlife. Natural Resources & Environment.

France, J.W., I.A. Alvi, P.A. Dickson, H.T. Falvey, S.J. Rigbey, and J. Trojanowski. 2018. Independent forensic team report Oroville Dam spillway incident. Technical Report.

Garrett, B.L. 2010. Drowned memories: the submerged places of the Winnemem Wintu. Archaeologies 6: 346–371.

Gregory, R., L. Failing, G. Long. T. McDaniels, and D. Ohlson. 2011. Structured Decision Making: A Practical Guide to Environmental Management. Wiley-Blackwell, West Sussex, UK

Grabowski, Z.J., H. Chang, and E.F. Granek. 2018. Fracturing dams, fractured data: Empirical trends and characteristics of existing and removed dams in the United States. River Research and Applications 34: 526-537. 

Grantham, T., and P. Moyle. Flagging problem dams for fish survival. California WaterBlog, October 24, 2014.

Hansen, H.H., E. Forzono, A. Grams, L. Ohlman, C. Ruskamp, M.A. Pegg, and K.L. Pope. 2020. Exit here: strategies for dealing with aging dams and reservoirs. Aquatic Sciences 82.

Helfman, G.S. 2007. Fish conservation: a guide to understanding and restoring global aquatic biodiversity and fishery resources. Island Press, Washington D.C. USA.

Moser, S.C., and J.F. Hart. 2018. Paying it forward: the path toward climate-safe infrastructure in California. A report of the climate-safe infrastructure working group to the California State Legislature. Technical Report.

Null, S.E., J. Medellin-Azuara, A. Escriva, M. Lent, and J. Lund. 2014. Optimizing the  195–215Dammed: Water Supply Losses and Fish Habitat Gains from Dam Removal in California. Journal of Environmental Management 136: 121-131.

Perales, K.M., J. Rowan, and P.B. Moyle. 2015. Evidence of landlocked Chinook Salmon populations in California. North American Journal of Fisheries Management 35:1101–1105.

Poff, N.L., J.D. Allan, M.B. Bain, J.R. Karr, K.L. Prestegaard, B.D. Richter, R.E. Sparks, and J.C. Stromberg. 1997. The natural flow regime. BioScience 47: 769-784.

Quiñones, R.M, T. Grantham, B. N. Harvey, J. D. Kiernan, M. Klasson, A. P. Wintzer and P.B. Moyle. 2015. Dam removal and anadromous salmonid (Oncorhynchus spp.) conservation in California. Reviews in Fish Biology and Fisheries 25: 195–215. 

Rypel, A.L., T.D. Simonson, D.L. Oele, J.D.T Griffin, T.P. Parks, D. Seibel, C.M. Roberts, S. Toshner, L.S. Tate, and J. Lyons. 2019. Flexible classification of Wisconsin lakes for improved fisheries conservation and management. Fisheries 44: 225-238.

US Army Corps of Engineers: Federal Emergency Management Agency. National Inventory of Dams. 2018. Washington, DC USA https://nid.sec.usace.army.mil/ords/f?p=105:1.






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Black Lives Matter

We have elected to suspend our regular CalifornaWaterBlog.com posts for this week. 

Institutional racism is urgent and real, and should divert us from topics of California water at this time. The deaths of George Floyd, Breonna Taylor, Ahmaud Arbery, and countless others are horrific, and the effects of a pandemic are disproportionately affecting communities of color. At the Center for Watershed Sciences, we acknowledge that while we strive for equity and inclusion in our science in line with our Principles of Community, we have a long way to go to address racism and unconscious bias. 

We admire all who have flooded our social media and news this week with demonstrations of the great power of diversity in our nation and our scientific fields. We support and encourage everyone to have the hard conversations and do the hard work to learn more about how to better support all people in our communities. It is moments like this that remind us that bearing witness to racism and injustice is critical and must be a core part of our mission.

These are difficult and challenging times, where current thinking and actions have been inadequate. We have provided a list of resources courtesy of the Graduate Group in Ecology’s Diversity Committee to advance our work of creating a community that is safe, welcoming, and inclusive. We ask you to join us in advocating for and creating safe and equitable environments for living, working, and practicing science.


Executive Committee, Center for Watershed Sciences: Andrew L. Rypel, Jay Lund, Sarah Yarnell, Ryan Peek, Cathryn Lawrence, Thomas Harter

Principal Investigators, Students, Postdocs, and Researchers, Center for Watershed Sciences: Ann Willis, Carson Jeffres, John Durand, Anna Sturrock, Robert Lusardi, Rusty Holleman, Peter Moyle, Josue Medellin-Azuara, Katrina Jessoe, Caroline Newell, Amber Lukk, Scout Carlson, Ryan Hitchings, Francine DeCastro, Kimberly Luke, Elsie Platzer, Dylan Stompe, Brian Williamson, Aaron Sturtevant, Malte Willmes, Avery Kruger, Meghan Holst, Mollie Ogaz, Kelly Neal, Nick Corline, Priscilla Vasquez-Housley, Adriana Alarcon, Eric Holmes, Madeline Frey, Sage Lee, Miranda Tilcock, Marisa Levinson, Alexandra Chu, Christine Parisek, Rachelle Tallman, Gabriel Singer, Colby Hause, Emily Jacinto, David Ayers, Chris Jasper, Mattea Berglund, Parsa Saffarinia

Further Reading

Teaching and higher education:

Haynes, C., & Bazner, K. J. (2019). A message for faculty from the present-day movement for black lives. International Journal of Qualitative Studies in Education, 32(9), 1146-1161.

Aggie Brickyard Spring: Vol VIII 2019 ‘What’s On Your Mind?’: Everyday Actions to Up Your Inclusivity Game, by the GGE Diversity Committee: https://aggiebrickyard.github.io/posts/SpringVol-VIII/

Teaching in times of crisis: https://cft.vanderbilt.edu/guides-sub-pages/crisis/

Ways white people can take action for racial justice:

5 ways white people can take action in response to white and state-sanctioned violence: https://medium.com/@surj_action/5-ways-white-people-can-take-action-in-response-to-white-and-state-sanctioned-violence-2bb907ba5277

75 things white people can do for racial justice: https://medium.com/equality-includes-you/what-white-people-can-do-for-racial-justice-f2d18b0e0234

Guide to allyship: https://guidetoallyship.com/

Anti-racism resources for white people: https://docs.google.com/document/d/1BRlF2_zhNe86SGgHa6-VlBO-QgirITwCTugSfKie5Fs/mobilebasic

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An Introduction to State Water Project Deliveries

By Nicole Osorio

Most people in California receive some of their drinking water supply from the State Water Project (SWP). The SWP also supplies water to over 10% of California’s irrigated agriculture.  The SWP and its service area span much of California, delivering water to 29 wholesale contractors shown in Figure 1.

Each year, the Department of Water Resources announces SWP Table A allocations which inform water contractors’ SWP deliveries: “Table A”, “Carryover”, and “Article 21.”  What are these different SWP delivery categories and how do they work?

Fig 1

Figure 1: State Water Contractors (SWC) of California by Region (“Update on Delta Conveyance” 2019)

Table A, Carryover, and Article 21 are three types of SWP deliveries described in this post. Some additional, more minor, deliveries are made as: transfer and exchange Table A, and Pool Water deliveries.

The 2020 water year is dry, but the recent May storms led to the increased 2020 SWP Allocation from  15% to 20% of SWP contractors requested “Table A” delivery amounts. Figure 2 compares the initial and final SWP allocations from 1996-2020. Some lessons from this graph include:

  • 2006 was the last 100% allocation year, 14 years ago.
  • Final allocations usually increase significantly from the initial allocation estimate sent to SWP contractors (usually in October). However, final allocations (usually in May) could be less than initial allocation estimates in extreme dry years.
  • Drought years tend to have little or no increases from initial to final SWP allocations (such as 2007-2009 and 2012-2015).
  • It is likely that 2020’s final allocation will be 20%. The last 20% final allocation year was in 2015, one of the driest years on record.


Figure 2: Historical SWP Initial and Final Allocations (1996-2020) (CA DWR 2020b). May 2020 allocation seems likely to become the 2020 final.

Figure 3 shows Table A, Carryover, and Article 21 deliveries from 2000-2017. Minimum, average, and Maximum Table A and carryover statistics were combined because both are categorized under Table A water while Article 21 deliveries are made above the approved Table A amounts. 2014 had the least Table A and carryover deliveries at 475 TAF while 2003 contained the most at 3202 TAF.

fig 3

Figure 3: Historical SWP Deliveries (TAF) by category from 2000-2017 (Data from CA DWR 2009, 2012, and 2018).

What is Table A?

Table A allocations represent “a portion or all of the annual Table A amount requested by SWP water contractors and approved for delivery by DWR (CA DWR 2019).” DWR and the public water agencies and local water districts developed the SWP’s long-term water supply contracts in the 1960s. Table A contract amounts originated from these long-term contracts and have been amended. The 1994 Monterey Agreements significantly revised the long-term water supply contracts. Table 1 presents each contractor’s maximum Table A contract delivery amount, adding up to 4.17 million AF, anticipated to be the SWP’s ultimate delivery capability in the 1960s (an amount rarely actually available). As a wet year example, the last column indicates how much each water contractor utilized their Max Table A amount in 2006, a 100% allocation year. San Joaquin contractors were more likely to take their full Table A and supplement water supplies with Article 21 water, described later.


Table 1: Share of total Maximum Table A amount (4.17 MAF) between all 29 SWP Contractors at Calendar Year 2020 (CA DWR 2019) and % Utilization of Table A deliveries at 100% Allocation year in 2006 (CA DWR 2015). Largest Table A contract holders and highest 100%  allocation utilizers highlighted. 2006 total deliveries also include turnback pool water.

What is Carryover water?

Carryover water is a portion of Table A water that contractors may save for next year’s delivery. Carryover requests allow SWP contractors to store some of their annual allocation for the next year, and not lose undelivered allocation at the end of the SWP contract year, December 31. When contractors request carryover for next year’s delivery, that water is stored in the SWP’s share of San Luis reservoir in Merced County.

However, storing carryover water in San Luis reservoir has a low operating priority and so brings a risk. SWP contractors can lose this stored carryover water when San Luis Reservoir fills. In the 2017 wet year, some contractors (Santa Barbara County , Crestline Lake Arrowhead Water Agency and San Gorgonio Pass Water Agency) needed to transfer their carryover water from San Luis to another non-SWP facility to prevent losing their carryover storage. Figure 4 shows how San Luis filled in 2017 for the first time since 2011, following the 2012-2016 drought.


Figure 4: San Luis reservoir levels (TAF) from January 2000 to April 2020 with wettest and driest water year designations using the Sacramento Valley Index (CA DWR 2020a; c).

Overall, San Luis carryover water provides water contractors with a safety net in dry years, like 2020. During the 2012-2016 drought, contractors almost exclusively relied on only Table A and carryover. 2014 was the only year when carryover deliveries (383 TAF) exceeded those of Table A (92 TAF) (Figure 3). Carryover storage acts as a “savings bank account” which water agencies can draw on in dry conditions, but at some risk in very wet years.

What is Article 21 water?

Article 21 (described in water contracts) allows water contractors to take deliveries above approved and scheduled Table A amounts (CA DWR 2019). Article 21 is sometimes called interruptible, unscheduled, or surplus water.  It is offered predominantly in wet years (2005, 2006, 2011, and 2017) (Figure 5).


Figure 5: Historical Article 21 deliveries from 2000-2017 (Maven’s Notebook, 2018)

As an ephemeral surplus supply, contractors cannot “request” and schedule Article 21 deliveries in advance. DWR can only offer Article 21 deliveries when (CA DWR 2018, 2019; CA WATER COMMISSION: Article 21 water, explained):

  1. Article 21 deliveries do not interfere with SWP allocations.
  2. Excess water is available in the Delta.
  3. Conveyance is not being used for SWP purposes or scheduled SWP deliveries.
  4. Article 21 water may not become Carryover water, stored in SWP facilities.

The different types of SWP deliveries are akin to managing household finances. Table A deliveries are like a monthly paycheck for fixed recurring expenses. Carryover requests let you save part of your “Table A paycheck” for the future. Lastly, Article 21 deliveries are like an unusual annual bonus. You could splurge your “Article 21 water” bonus for direct retail delivery, or save it in an aquifer or reservoir outside the SWP.

In California’s highly variable climate, each water contractor must match these SWP water supplies, other local and regional water resources, and water demands for this year’s water use and in preparing for future droughts. In this dry 2020 year, SWP contractors are likely aware that the next drought could be just around the corner.

Nicole Osorio is a first year Master’s student of Water Resources Civil Engineering at the University of California, Davis.

Further Readings

CA DWR and State Water Contractors. (1994). The Monterey Agreement – Statement of Principles by the State Water Contractors and the State of California, Department of Water Resources for Potential Amendments to the State Water Supply Contracts. <http://www.mwdh2o.com/PDFUWMP/1994%20Monterey%20Agreement%20and%20Amendment.pdf > (May 04, 2020)

CA DWR. (1996). Bulletin 132-95: Management of the California State Water Project. Sacramento, CA. <https://water.ca.gov/LegacyFiles/swpao/docs/bulletins/bulletin132/Bulletin132-95.pdf&gt; (May 04, 2020)

CA DWR. (2009). DRAFT: The State Water Project Delivery Reliability Report 2009. Sacramento, CA.

CA DWR. (2015). The State Water Project Final Delivery Capability Report 2015. Sacramento, CA.

CA DWR. (2018). The Final State Water Project Delivery Capability Report 2017. Sacramento, CA.

CA DWR. (2019). Bulletin 132-17: Management of the California State Water Project. Sacramento, CA, 547.

CA DWR. (2020a). “California Data Exchange Center.” California Data Exchange Center, <https://cdec.water.ca.gov/&gt; (Apr. 27, 2020).

CA DWR. (2020b). “State Water Project Historical Table A Allocations: Years 1996-2020.” <https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/State-Water-Project/Management/SWP-Water-Contractors/Files/SWP-Allocation-Progression-96-20-031920.pdf&gt; (Apr. 25, 2020).

CA DWR. (2020c). “Water Year Hydrologic Classification Indices.” Department of Water Resources California Data Exchange Center, <http://cdec.water.ca.gov/reportapp/javareports?name=WSIHIST&gt; (May 23, 2020).

Maven’s Notebook. (2018). “CA Water Commission: Article 21 water, explained.” MAVEN’S NOTEBOOK | Water news, <https://mavensnotebook.com/2018/04/05/ca-water-commission-article-21-water-explained/&gt; (Apr. 25, 2020).

Update on Delta Conveyance.” (2019). <http://mwdh2o.granicus.com/MediaPlayer.php?view_id=12&clip_id=7842&gt; (Nov. 14, 2019).

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Drawing boundaries with DNA to improve conservation

by Ryan Peek

Foothill Yellow-legged Frogs have begun to spawn, laying small snow-globe sized egg masses in streams and rivers. They are one of the few stream-breeding frogs endemic to California and Oregon. This species is a good indicator of stream health because they link aquatic and terrestrial ecosystems and are strongly tied to natural seasonal cues associated with local hydrology. Historically, they occurred in streams and rivers throughout California and Oregon, but, as with many amphibians, they have precipitously declined in many parts of their range due to river regulation, habitat loss, and disease.

First petitioned for listing under the California Endangered Species Act (CESA) in 2016 by the Center for Biological Diversity, the California Fish and Game Commission recently listed Foothill Yellow-legged Frogs (Rana boylii) in February 2020. But unlike other species listed under CESA, Foothill Yellow-legged Frogs are one of the first species where genetic data were used to introduce more nuance into the regulatory process. Only a few other species have used a genetic basis to identify groups for listing under the CESA. For example, Coho Salmon Oncorhynchus kisutch (listed in 1995) used a single status listing for the species based on existing genetic data. Similarly, the Fisher (Pekania pennanti) was also listed/not listed using evolutionarily significant units (ESUs), but the species is extremely geographically separated, unlike the historically wide-ranging Foothill Yellow-legged Frog. For Foothill Yellow-legged Frogs, different genetically distinct groups were given different listing status (Threatened, Endangered, or listing not warranted at this time). This listing is not an endpoint, it reflects successful collaboration between researchers and regulators to provide a pathway to better prioritize long-term management and conservation of one of California’s iconic species.

Fig. 1. A Foothill Yellow-legged Frog (Rana boylii).

While protecting and conserving one of our few native frog species is important, using the same uniform listing and management strategy for every frog population in California may not be practical. The Foothill Yellow-legged Frog has a large range that historically encompassed most of California, thus a blanket approach to listing and conservation management across the state may not be very effective. Different regions of the state have different impacts on the species; therefore it makes sense and is likely more effective and cost-efficient to manage conservation at a regional scale. A more nuanced approach also avoids placing a regulatory burden on entities in areas where the species appears to be doing well. Finding options to build more flexibility into the system we use to manage and conserve our natural resources is important for long-term success. The crux of this success is best illustrated by a deceptively straightforward map (Figure 2). Despite its simplicity, this map is a result of several years of genetic research and collaboration between multiple agencies and universities. Its use in the state listing process is a relatively novel application of conservation genetics.

Ultimately the boundaries on this map provide a flexible but robust way to prioritize each clade or genetic group  independently. Because each group is genetically distinct, the map allows us to describe each group using metrics that include genetic diversity as well as landscape change and flow alteration. Measuring genetic diversity within and among each of these groups is important because genetic diversity provides a species with the ability to adapt to changing conditions (i.e., evolve). A loss of diversity often signals extreme population and range reductions, and is associated with a loss of fitness (reproductive success and survival). Genetic data enables us to quantify which groups had more or less genetic diversity, and this was combined with regional information about the impacts of flow regulation, habitat alteration, and disease, to identify which groups may be most at risk of extinction. This allowed the CDFW to identify, prioritize, and list each clade separately, and make clade-specific listing recommendations, which provided a much more practical way to evaluate and apply CESA in a historically wide-ranging species (CDFW 2020).

And importantly, there was consensus in these findings; a separate independent study conducted at UCLA found a strikingly similar pattern, lending additional support to these genetic boundaries (McCartney-Melstad et al. 2018). The boundaries on this map can be updated, and these data provide additional benchmarks that give us insight into the status and health of different populations which can be compared across time and location. Translating the information that DNA provides us provides a powerful tool to help bridge the need for “the best available science” in conservation, but ultimately the most effective tools rely on our ability to collaborate and communicate across boundaries.

The map shows the genetic boundaries for distinct interbreeding populations, called clades, for the Foothill Yellow-legged Frog. This map helped define how and where the Foothill Yellow-legged Frog would be listed under CESA, and it provides a unique and powerful way to use DNA as a way to inform conservation.

Fig. 2. Foothill Yellow-legged Frog (Rana boylii) genetic groups or “clades.” (Peek 2018).

Drawing boundaries with DNA is not new. Delineating geographic ranges for organisms based on their underlying genetic code has been one of the foundational components of population genetics, but integrating this information into legal conservation frameworks like the state and federal Endangered Species Acts has been a slow process. The Endangered Species Act requires decisions be based on the “best available science.” While this sounds like a decision that would be heavily based on quantifiable data, it requires judgement and interpretation to incorporate the full spectrum of biological data when classifying a species as Endangered, Threatened, or listing not warranted. With the advent of modern genetics, the types of data that can be used can be powerful and informative, but also complicated and very dense. So how do we use genetic tools and translate this information into defensible policy and legal conclusions?

In an era where we can generate more data than ever before, where specializations abound, and the competition to maintain funding to conduct research has greatly emphasized novelty, the ability to translate across disciplines and find ways to effectively apply science may seem rare. Ultimately, there is a continuum between research and management, and from a management perspective, the best information is actionable, discrete, and can be integrated into existing policy frameworks. For scientists interested in applied research, this means understanding the context where the research may be used, identifying what gaps exist within a given framework, and actually talking with the folks who will use the science.

When I started my dissertation, I tried to think critically about what would be useful for management. I spent time talking to resource managers at state and federal agencies, and I tried to maintain communication and collaborations throughout the process. In particular, I tried to ask what pieces of information or research would be critical for helping inform conservation of the species. Maps are crucial for identifying, prioritizing, and planning, so identifying and refining boundaries for conservation units (distinct populations, or clades) was an important component in the listing process. In the end, some key pieces of my dissertation were used in the Status Review used for the California Department of Fish & Wildlife (CDFW) listing recommendations for the Foothill Yellow-legged Frog (CDFW 2019). While it is bittersweet to work with a species that is at risk of extinction, it is encouraging to participate and contribute in a meaningful way to a conservation process as a scientist.

Ryan Peek is a post-doctoral researcher at the Center for Watershed Sciences, UC Davis.

Further Reading:

California Department of Fish and Wildlife (CDFW). (2019). A Status Review Of The Foothill Yellow-legged Frog (Rana boylii) In California. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=174663&inline

CDFW. (2020). Notice of Findings for Foothill Yellow-legged Frog (Listing Decision). https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=177905&inline

McCartney-Melstad, E., Gidiş, M., & Shaffer, H. B. (2018). Population genomic data reveal extreme geographic subdivision and novel conservation actions for the declining Foothill Yellow-legged Frog. Heredity121(2), 112–125.

Peek, R.A. (2018). Population Genetics of a Sentinel Stream-breeding Frog (Rana boylii) [Ecology]. PhD Dissertation. University of California, Davis.

Peek, R. (2020). Rana boylii Population Genetics website. https://ryanpeek.org/flexdash_rabo.html


Laura Patterson has been instrumental as an contributor and collaborator; she coordinated and prepared the status review report for CDFW. In addition, Brad Shaffer, Sarah Kupferberg, Amy Lind, Sarah Yarnell, and Jennifer Dever have all provided data and critical research towards conservation of this species.

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