By Alex Rabidoux, Assistant General Manager, Solano County Water Agency
For decades, California has debated how much water should flow through its rivers to help recover struggling salmon populations. But an equally important question deserves attention: What happens to that water once it enters the river and how much ecological benefit does it actually provide?
Salmon evolved in rivers connected to expansive floodplains, wetlands and side channels. Seasonal flows created shallow, food-rich habitats where juvenile fish could feed, grow and find refuge before migrating to the ocean. Their survival depended not simply on the amount of water moving downstream, but on how that water interacted with the surrounding landscape.
Today, much of that connectivity has been lost. Modern restoration science recognizes that recovering salmon requires strategically timed flows that reconnect rivers with productive habitats, the reactivation of floodplains, and restoring the ecological functions that once supported abundant fish populations.
Photograph of the Winters Putah Creek Nature Park and Percolation Dam in 2005.
Putah Creek – The Beginning of a Successful but Incomplete Story
Putah Creek is a small tributary of the Sacramento River that flows through the communities of Winters, UC Davis, and just south Davis and eventually into the Yolo Bypass. Beginning in the late 1800s and continuing through the 1950s, several major transformations occurred on Putah Creek that included (a) the diversion of Putah Creek south of Davis, (b) the construction of the Yolo Bypass and corresponding levees along Putah Creek, and (c) the development of the Solano Project. While the results provided significant flood control and water supply benefits to downstream communities, it also changed Putah Creek from a highly variable intermittent stream to a highly managed perennial stream disconnected from its natural floodplain.
However, during the severe 1987-1992 drought, portions of Lower Putah Creek went dry, resulting in fish kills, and the start of almost a decade of litigation from 1991-2000. Eventually, in 2000 a settlement was reached between the Yolo and Solano parties, that balanced environmental flows including the early concept of functional flows with water supply reliability, resulting in the Putah Creek Accord. In addition to flows, the Accord required partial funding for a Streamkeeper, vegetation enhancement, wildlife monitoring, and native fish monitoring.
Photograph of the Winters Putah Creek Nature Park in 2012.
Putah Creek – Habitat Improvements, the Remaining Ingredient for Success
In the early years of the Accord, the first Streamkeeper began rebuilding landowner relationships (as 70% of the creek is privately owned), conducted trash and tire removal (with an occasional car and fuel tank), and invasive weed management. In 2005, the first large-scale habitat restoration project was done on Lower Putah Creek just upstream of the City of Winters, with the goal of reconnecting a natural gravel supply to the creek, improve salmonid habitat, and remove invasive plant species including Arundo and Himalayan Blackberry. Later, in 2009 the highly degraded Winters Percolation Dam was removed which eliminated a major fish passage impediment in Lower Putah Creek and was the start of a restoration and transformation process along the creek. Subsequently, in 2011 and 2014 almost 1-mile of channel was restored in the community of Winters, narrowing the main channel, establishing an inset floodplain, adding channel complexity, removing invasive plant species, establishing a new riparian corridor of native plant species, and providing public access for the community to enjoy. Figures 1-3 below show the transformation process of what was a highly degraded creek section to an area of active salmon spawning.
Starting in 2013, UC Davis scientists began to see increased and consistent numbers of returning Chinook salmon in Lower Putah Creek. While salmon had been periodically found post-Accord, the numbers were low and highly sporadic, even though the Accord flows had been occurring for almost 13-years. Instead, it was the culmination of flow, invasive species management, and habitat restoration that finally led to the consistent return of salmon in Lower Putah Creek.
Photograph of the Winters Putah Creek Nature Park in 2025.
Putah Creek – Record Run 2025
In Fall 2025, UC Davis scientists recorded the largest return on record for Putah Creek of 2,150 Chinook salmon. While no single action was responsible, it was instead a culmination of activities including strategically timed flows, improved fish passage, restored spawning gravels, improved habitat, reactivation of floodplains, invasive species management, and streamside vegetation. That same scientific thinking is the foundation of the Healthy Rivers and Landscapes (HRL) program. No single restoration strategy can guarantee success.
Putah Creek is a great example, where collaboration, partnership, and scientific understanding was the recipe for success. It was the willingness of stakeholders to collaborate, the building of trust between landowners and local public agencies, as well as the long-term scientific monitoring by UC Davis, SCWA, and many other partners. The large-scale restoration projects on Putah Creek would also not have been possible without state grant funding and local funding from SCWA well beyond the Accord requirements. Lastly, it is important to recognize the dedicated staff, scientists, engineers, educators, and volunteers across all the organizations that have helped in each of their roles to help motivate, educate, and restore Lower Putah Creek.
As the famous philosopher Dr. Seuss wrote from the Lorax, “Unless someone like you cares a whole awful lot, nothing is going to get better. It’s not.”
Note: The views and opinions expressed in this commentary are those of the author and do not necessarily reflect the official policy or position of Maven’s Notebook.
More coverage of the Voluntary Agreements on Maven’s Notebook …
By Dan Walters, Cal Matters This commentary was originally published by CalMatters. Sign up for their newsletters. Gray Davis became governor in 1999 and one of his first acts was to decree that there would be no major changes in water policy for eight years, which he assumed would be his two terms in office. Davis, a veteran politician who had climbed the political ladder one rung at a time, was well aware of the decades-long stalemate on the fundamental […]
Framework combines new flows, habitat restoration, science and enforceable rules to protect the Sacramento River and Delta From the State Water Board: In a landmark development driving large-scale ecosystem restoration and creating greater security for the heart of California’s water system, the State Water Resources Control Board today adopted modernized water quality protections for the Sacramento River and San Francisco Bay-Delta. The updated Water Quality Control Plan for the San Francisco Bay/Sacramento-San Joaquin Delta Watershed (Bay-Delta Plan) strengthens protections for […]
California approved Newsom’s Delta water rules, but Trump threatens to pull out and $740M with it. Water agencies that once backed the deal call it too strict; environmentalists say it’s too weak. By Rachel Becker, Cal Matters This story was originally published by CalMatters. Sign up for their newsletters. California water regulators have approved a new plan overhauling how farms and cities take water from the Sacramento-San Joaquin Delta and rivers that feed it, setting up the next fight over Gov. […]
Under the changes, water agencies can commit to voluntary agreements governing water usage that some environmentalists and tribes argue undermine the health of the Bay-Delta system. By Alan Riquelmy, Courthouse News Service California’s water board late Thursday approved major changes to a massive water plan that drew strong emotions, and at times sharp rebukes, from hundreds of stakeholders including water agencies, conservationists and tribes. The plan sets water quality goals for the San Francisco Bay/Sacramento-San Joaquin Delta, a massive watershed […]
Groups condemn the Newsom administration’s voluntary agreement framework, pledging to fight for water rights, environmental protections, and due process From Restore the Delta: In anticipation of the State Water Resources Control Board’s vote to adopt the updated Bay-Delta Plan, tribal leaders, environmental advocates, and Delta residents gathered at a press conference to condemn the decision and pledge further action to defend California’s water rights, protect critical ecosystems, and ensure meaningful public participation in decisions affecting the state’s water future. Representatives […]
The Bay-Delta is a watershed that provides drinking and municipal water to some 30 million people, along with irrigation water for 4 million acres. From the Courthouse News Service People and agencies facing the effects of proposed changes to a major California water plan spoke in waves Wednesday, making their cases to the state’s water board. The State Water Resources Control Board is proposing amendments to the San Francisco Bay/Sacramento-San Joaquin Delta water quality control plan. The plan sets water […]
By Alex Rabidoux, Assistant General Manager, Solano County Water Agency For decades, California has debated how much water should flow through its rivers to help recover struggling salmon populations. But an equally important question deserves attention: What happens to that water once it enters the river and how much ecological benefit does it actually provide? Salmon evolved in rivers connected to expansive floodplains, wetlands and side channels. Seasonal flows created shallow, food-rich habitats where juvenile fish could feed, grow and […]
By the Delta Tribal Environmental Coalition, consisting of the Shingle Springs Band of Miwok Indians, Winnemem Wintu Tribe, Little Manila Rising, and Restore the Delta. California has formally apologized to tribes for state-sanctioned atrocities and committed to improving relationships between the state and tribal governments. Our elected leaders have also passed numerous laws intended to advance environmental justice outcomes. Yet, when it comes to decisions for the Sacramento-San Joaquin watershed, the Newsom administration has thrown tribes and environmental justice communities […]
From the Golden Gate Salmon Association Later this week, the State Water Resources Control Board is likely to adopt a final update to the Bay-Delta Plan. This plan is the state’s key document to protect the natural resources in the vast Bay-Delta estuary, as well as its Central Valley tributary rivers. This is the largest freshwater ecosystem in California and the largest estuary on the West Coast. Sacramento Valley salmon runs are the backbone of salmon fishing in California and […]
Healthy Rivers and Landscapes provides critical habitat for salmon while also ensuring our farms, cities and rural communities remain vibrant By Nicole Montna Van Vleck, President and CEO, Montna Farms Think about the last time you enjoyed a piece of sushi or took a bite of pizza. The rice wrapped around your favorite sushi roll, the tomato sauce, the cheese, perhaps a few peppers or olives sprinkled on top of that perfect slice. Chances are, you weren’t thinking about the […]
COMMENTARY: The science is clear: Restoring California’s salmon populations requires more than just water
By Alex Rabidoux, Assistant General Manager, Solano County Water Agency
For decades, California has debated how much water should flow through its rivers to help recover struggling salmon populations. But an equally important question deserves attention: What happens to that water once it enters the river and how much ecological benefit does it actually provide?
Salmon evolved in rivers connected to expansive floodplains, wetlands and side channels. Seasonal flows created shallow, food-rich habitats where juvenile fish could feed, grow and find refuge before migrating to the ocean. Their survival depended not simply on the amount of water moving downstream, but on how that water interacted with the surrounding landscape.
Today, much of that connectivity has been lost. Modern restoration science recognizes that recovering salmon requires strategically timed flows that reconnect rivers with productive habitats, the reactivation of floodplains, and restoring the ecological functions that once supported abundant fish populations.
Putah Creek – The Beginning of a Successful but Incomplete Story
Putah Creek is a small tributary of the Sacramento River that flows through the communities of Winters, UC Davis, and just south Davis and eventually into the Yolo Bypass. Beginning in the late 1800s and continuing through the 1950s, several major transformations occurred on Putah Creek that included (a) the diversion of Putah Creek south of Davis, (b) the construction of the Yolo Bypass and corresponding levees along Putah Creek, and (c) the development of the Solano Project. While the results provided significant flood control and water supply benefits to downstream communities, it also changed Putah Creek from a highly variable intermittent stream to a highly managed perennial stream disconnected from its natural floodplain.
However, during the severe 1987-1992 drought, portions of Lower Putah Creek went dry, resulting in fish kills, and the start of almost a decade of litigation from 1991-2000. Eventually, in 2000 a settlement was reached between the Yolo and Solano parties, that balanced environmental flows including the early concept of functional flows with water supply reliability, resulting in the Putah Creek Accord. In addition to flows, the Accord required partial funding for a Streamkeeper, vegetation enhancement, wildlife monitoring, and native fish monitoring.
Putah Creek – Habitat Improvements, the Remaining Ingredient for Success
In the early years of the Accord, the first Streamkeeper began rebuilding landowner relationships (as 70% of the creek is privately owned), conducted trash and tire removal (with an occasional car and fuel tank), and invasive weed management. In 2005, the first large-scale habitat restoration project was done on Lower Putah Creek just upstream of the City of Winters, with the goal of reconnecting a natural gravel supply to the creek, improve salmonid habitat, and remove invasive plant species including Arundo and Himalayan Blackberry. Later, in 2009 the highly degraded Winters Percolation Dam was removed which eliminated a major fish passage impediment in Lower Putah Creek and was the start of a restoration and transformation process along the creek. Subsequently, in 2011 and 2014 almost 1-mile of channel was restored in the community of Winters, narrowing the main channel, establishing an inset floodplain, adding channel complexity, removing invasive plant species, establishing a new riparian corridor of native plant species, and providing public access for the community to enjoy. Figures 1-3 below show the transformation process of what was a highly degraded creek section to an area of active salmon spawning.
Starting in 2013, UC Davis scientists began to see increased and consistent numbers of returning Chinook salmon in Lower Putah Creek. While salmon had been periodically found post-Accord, the numbers were low and highly sporadic, even though the Accord flows had been occurring for almost 13-years. Instead, it was the culmination of flow, invasive species management, and habitat restoration that finally led to the consistent return of salmon in Lower Putah Creek.
Putah Creek – Record Run 2025
In Fall 2025, UC Davis scientists recorded the largest return on record for Putah Creek of 2,150 Chinook salmon. While no single action was responsible, it was instead a culmination of activities including strategically timed flows, improved fish passage, restored spawning gravels, improved habitat, reactivation of floodplains, invasive species management, and streamside vegetation. That same scientific thinking is the foundation of the Healthy Rivers and Landscapes (HRL) program. No single restoration strategy can guarantee success.
Putah Creek is a great example, where collaboration, partnership, and scientific understanding was the recipe for success. It was the willingness of stakeholders to collaborate, the building of trust between landowners and local public agencies, as well as the long-term scientific monitoring by UC Davis, SCWA, and many other partners. The large-scale restoration projects on Putah Creek would also not have been possible without state grant funding and local funding from SCWA well beyond the Accord requirements. Lastly, it is important to recognize the dedicated staff, scientists, engineers, educators, and volunteers across all the organizations that have helped in each of their roles to help motivate, educate, and restore Lower Putah Creek.
As the famous philosopher Dr. Seuss wrote from the Lorax, “Unless someone like you cares a whole awful lot, nothing is going to get better. It’s not.”
Additional Reading
Hansen, Todd R. “Putah Creek Accord, Now 20, Remains Key to Habitat, Restoration, Water Flows.” The Davis Enterprise, May 24, 2020, p. A1. Online version crossposted by Cool Davis, June 3, 2020. https://www.cooldavis.org/2020/06/03/after-20-years-putah-creek-accord-still-key-to-habitat-water-flows/
Harold Rubin, The Solano Water Story: A History of the Solano Irrigation District and the Solano Project (Solano Irrigation District, 1988). https://www.sidwater.org/DocumentCenter/View/366/The-Solano-Water-Story?bidId=
Rabidoux, A., Stevenson, M., Moyle, P. B., Miner, M. C., Hitt, L. G., Cocherell, D. E., Fangue, N. A., & Rypel, A. L. (2022, April 24). The Putah Creek fish kill: Learning from a local disaster. California Water Blog, UC Davis Center for Watershed Sciences. https://californiawaterblog.com/2022/04/24/the-putah-creek-fish-kill-learning-from-a-local-disaster/
The Putah Creek Legacy. (2014). The Davis Enterprise & Climate Confidential. https://www.putahcreeklegacy.com/
More coverage of the Voluntary Agreements on Maven’s Notebook …
DAN WALTERS: California adopted a new water plan. It’s unlikely to end the state’s water wars
By Dan Walters, Cal Matters This commentary was originally published by CalMatters. Sign up for their newsletters. Gray Davis became governor in 1999 and one of his first acts was to decree that there would be no major changes in water policy for eight years, which he assumed would be his two terms in office. Davis, a veteran politician who had climbed the political ladder one rung at a time, was well aware of the decades-long stalemate on the fundamental […]
PRESS RELEASE: State Water Board adopts innovative new model to protect California’s Bay-Delta, water and wildlife
Framework combines new flows, habitat restoration, science and enforceable rules to protect the Sacramento River and Delta From the State Water Board: In a landmark development driving large-scale ecosystem restoration and creating greater security for the heart of California’s water system, the State Water Resources Control Board today adopted modernized water quality protections for the Sacramento River and San Francisco Bay-Delta. The updated Water Quality Control Plan for the San Francisco Bay/Sacramento-San Joaquin Delta Watershed (Bay-Delta Plan) strengthens protections for […]
CAL MATTERS: Has the Trump administration doomed Newsom’s water plan?
California approved Newsom’s Delta water rules, but Trump threatens to pull out and $740M with it. Water agencies that once backed the deal call it too strict; environmentalists say it’s too weak. By Rachel Becker, Cal Matters This story was originally published by CalMatters. Sign up for their newsletters. California water regulators have approved a new plan overhauling how farms and cities take water from the Sacramento-San Joaquin Delta and rivers that feed it, setting up the next fight over Gov. […]
COURTHOUSE NEWS: California water board passes major water plan after marathon session
Under the changes, water agencies can commit to voluntary agreements governing water usage that some environmentalists and tribes argue undermine the health of the Bay-Delta system. By Alan Riquelmy, Courthouse News Service California’s water board late Thursday approved major changes to a massive water plan that drew strong emotions, and at times sharp rebukes, from hundreds of stakeholders including water agencies, conservationists and tribes. The plan sets water quality goals for the San Francisco Bay/Sacramento-San Joaquin Delta, a massive watershed […]
RESTORE THE DELTA: Tribes and environmental groups slam State Water Board’s anticipated adoption of updated Bay-Delta Plan, vow further action
Groups condemn the Newsom administration’s voluntary agreement framework, pledging to fight for water rights, environmental protections, and due process From Restore the Delta: In anticipation of the State Water Resources Control Board’s vote to adopt the updated Bay-Delta Plan, tribal leaders, environmental advocates, and Delta residents gathered at a press conference to condemn the decision and pledge further action to defend California’s water rights, protect critical ecosystems, and ensure meaningful public participation in decisions affecting the state’s water future. Representatives […]
COURTHOUSE NEWS: California water board hears competing views on major water plan update
The Bay-Delta is a watershed that provides drinking and municipal water to some 30 million people, along with irrigation water for 4 million acres. From the Courthouse News Service People and agencies facing the effects of proposed changes to a major California water plan spoke in waves Wednesday, making their cases to the state’s water board. The State Water Resources Control Board is proposing amendments to the San Francisco Bay/Sacramento-San Joaquin Delta water quality control plan. The plan sets water […]
COMMENTARY: The science is clear: Restoring California’s salmon populations requires more than just water
By Alex Rabidoux, Assistant General Manager, Solano County Water Agency For decades, California has debated how much water should flow through its rivers to help recover struggling salmon populations. But an equally important question deserves attention: What happens to that water once it enters the river and how much ecological benefit does it actually provide? Salmon evolved in rivers connected to expansive floodplains, wetlands and side channels. Seasonal flows created shallow, food-rich habitats where juvenile fish could feed, grow and […]
COMMENTARY: Reject the discriminatory, illegitimate, and harmful Voluntary Agreements
By the Delta Tribal Environmental Coalition, consisting of the Shingle Springs Band of Miwok Indians, Winnemem Wintu Tribe, Little Manila Rising, and Restore the Delta. California has formally apologized to tribes for state-sanctioned atrocities and committed to improving relationships between the state and tribal governments. Our elected leaders have also passed numerous laws intended to advance environmental justice outcomes. Yet, when it comes to decisions for the Sacramento-San Joaquin watershed, the Newsom administration has thrown tribes and environmental justice communities […]
GUEST COMMENTARY: Fatal flaws in the State Water Board’s Draft Bay-Delta Plan Update
From the Golden Gate Salmon Association Later this week, the State Water Resources Control Board is likely to adopt a final update to the Bay-Delta Plan. This plan is the state’s key document to protect the natural resources in the vast Bay-Delta estuary, as well as its Central Valley tributary rivers. This is the largest freshwater ecosystem in California and the largest estuary on the West Coast. Sacramento Valley salmon runs are the backbone of salmon fishing in California and […]
GUEST COMMENTARY: Healthy Rivers and Landscapes: A healthier future for all of California
Healthy Rivers and Landscapes provides critical habitat for salmon while also ensuring our farms, cities and rural communities remain vibrant By Nicole Montna Van Vleck, President and CEO, Montna Farms Think about the last time you enjoyed a piece of sushi or took a bite of pizza. The rice wrapped around your favorite sushi roll, the tomato sauce, the cheese, perhaps a few peppers or olives sprinkled on top of that perfect slice. Chances are, you weren’t thinking about the […]
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