UC Davis Center for Watershed Sciences

By Ted Sommer and Jeffrey Mount Introduction The conservation of freshwater biodiversity has emerged as a global challenge. The loss of habitat and the changing climate are reducing the viability of native freshwater species worldwide—and California is no exception to this. For decades the state has struggled to protect its native species. Today, roughly half of California’s native freshwater plants and animals are vulnerable to extinction by the end of this century (Howard et al....

Conserving California’s Freshwater Biodiversity Under Climate Change By Ted Sommer and Jeffrey Mount Introduction The conservation of freshwater biodiversity has emerged as a global challenge. The loss of habitat and the changing climate are reducing the viabil…

By Rosemary Hartman, Matt Young, Dylan Chapple, Stacy Sherman, Dave Ayers, Emma Mendonsa, Elizabeth Brusati, and Louise Conrad Figure 1. Dutch Slough Tidal Wetland Restoration site in the Sacramento San Joaquin Delta, near Oakley California. Photo Credit Florence Low for the Department of Water Resources. Tidal wetlands in the Sacramento – San Joaquin Delta used to be vast. You may have seen artistic renditions of how the landscape may have looked with meandering channels weaving through a mosaic of land and water and with teaming wildlife....

Restoration of Tidal wetlands of the Sacramento-San Joaquin Delta – Where are we at? By Rosemary Hartman, Matt Young, Dylan Chapple, Stacy Sherman, Dave Ayers, Emma Mendonsa, Elizabeth Brusati, and Louise Conrad Figure 1. Dutch Slough Tidal Wetland Restoration site in the Sacrament…

By Peter Moyle The California Fish Commission introduced American Shad into California in 1871 via milk crates shipped on the newly built transcontinental railroad (Dill and Cordone 1997). Shad, apparently the first non-native fish species (of 50) to become established in the state, were so well suited to California that in a few years, shad supported a commercial fishery in the San Francisco Estuary and had colonized the Columbia River to the north....

Amazing Invader: American Shad By Peter Moyle The California Fish Commission introduced American Shad into California in 1871 via milk crates shipped on the newly built transcontinental railroad (Dill and Cordone 1997). Shad, ap…

California has an extensive and complex water system. Can many people name all the waterways on this common California water map (with the names removed)? Give it a try. No cheating. (Unlike some map quizzes and the 1957 California Water Plan, this map has no imaginary features, except perhaps when some of the river channels run dry.) People probably know more near where they live and work, or places they have visited....

How well do you know California water? California has an extensive and complex water system. Can many people name all the waterways on this common California water map (with the names removed)? Give it a try. No cheating. (Unlike some m…

By Kim Luke & John Durand Zooplankton and their history in the San Francisco Estuary Figure 1. Image of a crustaceous zooplankton, known as a copepod. Photo credit: Zooplankton are tiny aquatic organisms unable to swim against currents; they include microscopic crustaceans, small jellyfish, and larval life stages of other organisms (Figure 1). Although zooplankton are small in size, they have a big impact on the food web because they connect primary producers (mostly phytoplankton) to bigger consumers (like fishes)....

The Big Impact of Small Waters: Zooplankton Density Trends in the North Delta By Kim Luke & John Durand Zooplankton and their history in the San Francisco Estuary Figure 1. Image of a crustaceous zooplankton, known as a copepod. Photo credit: Zooplankton are tiny aquatic…

By David Dralle, Gabe Rossi, Phil Georgakakos, Jesse Hahm, Daniella Rempe, Monica Blanchard, Mary Power, Bill Dietrich, and Stephanie Carlson You’ve probably noticed that some streams flow year-round while others are seasonally dry, despite receiving similar amounts of rainfall. Through a recent NSF-funded effort (“Eel River Critical Zone Observatory”), we learned several things about how landscapes filter climate to produce such diverse flow behavior–and the implications for how salmon live their lives....

Salmon and the Subsurface By David Dralle, Gabe Rossi, Phil Georgakakos, Jesse Hahm, Daniella Rempe, Monica Blanchard, Mary Power, Bill Dietrich, and Stephanie Carlson You’ve probably noticed that some streams flow year-rou…

by Jay Lund In practice, adaptive management wheels have squarish corners. In ideal adaptive management, there is a steady or periodic process for gathering performance and environmental data, analyzing that data in the context of an integrative computer model, discussions based on the analysis to determine the most promising adaptations of management to reflect this likely better understanding, and repeating this general process into the future (Holling 1978)....

Adaptive Management Wheels by Jay Lund In practice, adaptive management wheels have squarish corners. In ideal adaptive management, there is a steady or periodic process for gathering performance and environmental data, anal…

By Karrigan Börk A humpback chub, one of four endemic Colorado River fish species protected under the Upper Colorado River Endangered Fish Recovery Program. Water right exactions are a proposed tool to mitigate costs associated with water rights and water infrastructure that would also help users make better decisions about how much water to use. But first, what are exactions…...

Water Right Exactions By Karrigan Börk A humpback chub, one of four endemic Colorado River fish species protected under the Upper Colorado River Endangered Fish Recovery Program. Water right exactions are a proposed too…

by Peter Moyle William (Bill) Bennett. William A. Bennett (1955-2024) was a top-notch scientist/biologist who spent much of his career improving our understanding of the ecology and management of native and non-native fishes in the SF Estuary (SFE) especially delta smelt and striped bass. Those of us who had the good fortune to work with him knew Bill as an insightful biologist who worked hard to retain his objectivity on controversial fish management issues in the SFE....

Bill Bennett: friend of fish and fisheries in the San Francisco Estuary by Peter Moyle William (Bill) Bennett. William A. Bennett (1955-2024)  was a top-notch scientist/biologist who spent much of his career improving our understanding of the ecology and…

by Peter Moyle Seek Higher Ground: The Natural Solution to Our Urgent Flooding Crisis, by Tim Palmer. University of California Press 2024. Flooding is a natural phenomenon that we humans keep assuming can be controlled with enough effort and engineering. But this simply is not possible, as floods across the globe repeatedly demonstrate. People continue to be surprised when landscapes become waterscapes....

Book Review: Seek Higher Ground by Peter Moyle Seek Higher Ground: The Natural Solution to Our Urgent Flooding Crisis, by Tim Palmer. University of California Press 2024. Flooding is a …

Join us on Saturday, May 11, 2024, from 1 – 4pm at Winters Community Library!

The Center for Watershed Sciences is hosting a family-oriented science event in collaboration with the Winters Community Library! Encounter live fish straight from Putah Creek's waters, go bird watching in the library garden, engage with specimens from the Museum of Wildlife and Fish Biology, UC Davis, and unleash your inner biologist with some practice fish and aquatic bug sampling. With prizes and more, you don’t want to miss out on this bilingual, fun-for-the-whole-family event!

* This event will be offered in both English & Spanish, with live Spanish translators from UC Davis.

Please help us share this event widely! Learn more here: https://watershed.ucdavis.edu/news/putah-creek-themed-family-event-winters-community-library-may-11

by Ellen Bruno, Molly Bruce, and Katrina Jessoe For more than a century, parts of California have been using groundwater faster than the resource can be replenished. As a result, aquifers are dwindling—a mounting challenge for irrigators, communities, and ecosystems. The negative impacts of over-extraction include subsidence, shallower wells running dry, and water-quality deterioration. If overextraction remains unaddressed, groundwater will become more expensive and less reliable....

How to incentivize better groundwater use by Ellen Bruno, Molly Bruce, and Katrina Jessoe For more than a century, parts of California have been using groundwater faster than the resource can be replenished. As a result, aquifers are …

by Peter B. Moyle *This is a repost of a blog originally published in 2019. If you inspect small streams in northern California, including those that seem too small or warm for any fish, you will often see minnows swimming in the clear water. Chances are you are seeing a very distinctive native Californian, usually called California roach. This fish is a complex of species that occurs as far north as Oregon tributaries to Goose Lake and is widespread in tributaries to the Sacramento and San Joaquin rivers, as well as in rivers along the coast from the Eel River to Monterey....

Roaches of California: Hidden Biodiversity in a Native Minnow by Peter B. Moyle *This is a repost of a blog originally published in 2019. If you inspect small streams in northern California, including those that seem too small or warm for any fish, you will o…

California WaterBlog is a long-running outreach project from the UC Davis Center for Watershed Sciences, a research center dedicated to interdisciplinary study of water challenges, particularly in California. We focus on environmentally and economically sustainable solutions for managing rivers, lakes, groundwater, and estuaries. This week, for UC Davis Give Day (April 19-20) we’re sharing a little about the Center and the work we do....

Support our Students and Engagement at the Center for Watershed Sciences California WaterBlog is a long-running outreach project from the UC Davis Center for Watershed Sciences, a research center dedicated to interdisciplinary study of water challenges, particularly in …

By Andrew L. Rypel Fig. 1. Boardwalk leading to Julie Partansky Pond, Davis, CA. March 2024. Each morning is similar, but different. As we approach the pond on the wooden catwalk, you can hear the birds calling, eventually you start to smell the freshness of the ecosystem, the glitters and splashing ahead gives some indication of bird activity on the water....

Mornings at the Duck Pond By Andrew L. Rypel Fig. 1. Boardwalk leading to Julie Partansky Pond, Davis, CA. March 2024. Each morning is similar, but different. As we approach the pond on the wooden catwalk, you can hear the …

by Abigail Ward and Peggy Harte Salmon face many stressors that significantly reduce their survival. Persistent challenges include habitat degradation, predation, pollution, and climate change that threaten already at-risk populations. Conservation efforts in California engage with the complexity of these stressors, yet in recent years, a new threat has emerged to salmon restoration in the Central Valley. The absence of a seemingly inconspicuous nutrient, vitamin B1 or thiamine, has been impeding restoration....

Spinning Salmon in the Classroom by Abigail Ward and Peggy Harte Salmon face many stressors that significantly reduce their survival. Persistent challenges include habitat degradation, predation, pollution, and climate change that…

by E.J. Baybe-Mahn Successful aquatic restoration traditionally comes from extensive research and knowledge of the system, collaboration among stakeholders, and thorough planning. But what if there was another way to ensure restorations are creating the results we want to see? With increasing effects of climate change, urbanization, and other anthropogenic factors, aquatic organisms, especially ones that are endangered, need successful restorations more than ever to aid in their survival....

Manifesting Successful Aquatic Restoration by E.J. Baybe-Mahn Successful aquatic restoration traditionally comes from extensive research and knowledge of the system, collaboration among stakeholders, and thorough planning. But what if there…

by Jay Lund March is usually the last month in California’s mostly unpredictable wet season. A dry March can make a promising water year disappointing. A very wet March can make a potentially critically dry year be only mildly dry, like the “Miracle March” of 1991 (with three times average March precipitation). Unlike basketball, nobody prevails in California’s annual March Water Madness. ...

California’s March Water Madness by Jay Lund March is usually the last month in California’s mostly unpredictable wet season.  A dry March can make a promising water year disappointing.  A very wet March can make a poten…

“Some people say Alpaugh is the stepchild of Tulare County; I say we’re the forgotten ones. Rural families are an endangered species.” - Sandra Meraz, Dec 2014 in the LA Times...

Love Alpaugh: Celebrating the life and legacy of Sandra Meraz “Some people say Alpaugh is the stepchild of Tulare County; I say we’re the forgotten ones. Rural families are an endangered species.” – Sandra Meraz, Dec 2014 in the LA Times Sandra (bottom …

Join us for a webinar on environmental flows in Chile and California! The event will be on Tuesday, March 12, 2024, from 11:00 to 1:30 (PST). Learn more and register at the link: https://watershed.ucdavis.edu/news/webinar-312-instream-minimum-flows-experiences-and-lessons-california-chile

by Sarah Yarnell, Diego Rivera Salazar, Camila Boettiger, and Jay Lund Countries, regions, and river basins globally are struggling to provide and manage flows in rivers for ecosystems. One approach, of many, is a Functional Flows approach, because it seeks to provide a range of streamflows over the year and between years to support fundamental functions of river ecosystems and the ecosystem services for society....

A Functional Flows approach for Environmental Flows in Chile by Sarah Yarnell, Diego Rivera Salazar, Camila Boettiger, and Jay Lund Countries, regions, and river basins globally are struggling to provide and manage flows in rivers for ecosystems.  One a…

By Jay R. Lund *This is a repost of a blog originally published in 2012. Water management is often very different from what we think intuitively, or what we have been taught. Here are some examples. 1. Most water decisions are local. Water policy and management discussions often seem to assume that state and federal government decisions and funding are the most important aspects of water management....

Some curious things about water management By Jay R. Lund *This is a repost of a blog originally published in 2012. Water management is often very different from what we think intuitively, or what we have been taught. Here are some examples…

Congratulations Karrigan Börk, UC Davis Center for Watershed Sciences Associate Director & UC Davis Law acting professor, for being awarded Arizona State University College of Law's prestigious Morrison Prize for water rights research!

Karrigan Börk awarded ASU Law's Morrison Prize for water rights research Karrigan Börk, Associate Director at the Center for Watershed Sciences and acting professor of law at UC Davis' School of Law, has been awarded the Morrison Prize for his 2023 legal paper on water extraction rights. The $10,000 Morrison Prize is a distinguished honor; it is awarded annually to the ...

By Camila Boettiger, Karrigan Börk, Roberto Ponce Oliva, Diego Rivera, Jay Lund, and Sarah Yarnell California and Chile share a history of water allocation with little regard for instream uses of water, especially environmental uses. In California, for example, many water rights were obtained with no consideration of the environmental impacts of the water use, often because few environmental laws existed or were enforced when users obtained the rights....

Minimum Flow Laws in California and Chile By Camila Boettiger, Karrigan Börk, Roberto Ponce Oliva, Diego Rivera, Jay Lund, and Sarah Yarnell California and Chile share a history of water allocation with little regard for instream uses of w…

By Francisco J. Bellido-Leiva, Nicholas Corline, and Robert A. Lusardi About 1,500 dams obstruct, modify, and regulate flow in all but one of California’s major rivers. These dams provide Californians with reliable drinking and irrigation water, flood protection for low-lying communities, and hydropower for our electrical grid. But dams also threaten downstream ecosystems by severely disrupting natural processes with potentially dire consequences for native species....

Can large dams help feed downstream ecosystems? By Francisco J. Bellido-Leiva, Nicholas Corline, and Robert A. Lusardi About 1,500 dams obstruct, modify, and regulate flow in all but one of California’s major rivers. These dams provide Californi…

By Andrew L. Rypel Fig. 1. "Sampling" for bluegill on Lake Monona, Madison, Wisconsin. Before joining the faculty at UC Davis, I spent the previous five years as a research scientist at the Wisconsin Department of Natural Resources in Madison, Wisconsin. Apparently this experience is somewhat rare among academics. A peer even once described me as “approximating a unicorn”, which I’m still not sure is a good thing or a bad thing!...

Seven conservation lessons I learned in government work By Andrew L. Rypel Fig. 1. “Sampling” for bluegill on Lake Monona, Madison, Wisconsin. Before joining the faculty at UC Davis, I spent the previous five years as a research scientist at…

by Erin E Tracy, Jon A. Walter, Karrigan Bork, Anna Steel, Francisco J Bellido-Leiva, Scott Colborne, Sarah Yarnell Adult green sturgeon. Photo credit Dennis Cocherell Over 65 million years ago, as Tyrannosaurus rex roamed the great plains, green sturgeon (Acipenser medirostris) were already roaming the world’s waters. While these ancient fish survived the fall of dinosaurs, they are now in danger of extinction largely due to habitat degradation and losses from water management infrastructure and its operation (e.g., impairing flow, disrupting thermal regimes)....

Green Sturgeon aren’t Salmon: Updated life cycle models for management by Erin E Tracy, Jon A. Walter, Karrigan Bork, Anna Steel, Francisco J Bellido-Leiva, Scott Colborne, Sarah Yarnell Adult green sturgeon. Photo credit Dennis Cocherell Over 65 million years ago, as…

by Jay Lund Every water year is different in California, and in any water year, local and regional experiences often differ. California is a large state, far larger than most storm systems and atmospheric rivers with large topographic differences, so some parts of California are usually wetter or drier than others. Part of the rationale for California’s inter-regional water projects was to help average out geographic variability in water availability using canals, in addition to water storage which helps average water availability over time....

Even when most of California is dry doesn’t mean we can’t have floods by Jay Lund Every water year is different in California, and in any water year, local and regional experiences often differ.  California is a large state, far larger than most storm systems an…

by Jay Lund The first few months of California’s water year, which started in October 2023, have been pretty dry. We never know what to expect of California’s wet season until it ends, usually in late March. This year is no exception. Precipitation in California is almost uncorrelated from year to year (even with El Nino), so last year’s rain, snow, and streamflow doesn’t help much in predicting this year or next year’s water availability....

How’s California’s water year developing? – January 2024 by Jay Lund The first few months of California’s water year, which started in October 2023, have been pretty dry. We never know what to expect of California’s wet season until it ends, usually in l…