This increase is a ray of hope for California’s salmon population.
“Salmon has always been extremely important to our Indigenous culture, just along our state and the West Coast, and to the people who grew up in California.
The stream flows from the Mayakama mountains and Vaca Mountains to Solano County, with native cold water fish such as Chinook salmon, rainbow trout and steelhead.
However, after Lake Berrissa was created in the 1950s, native fish, especially unmanned fish such as salmon and steelhead, began to decline rapidly, Ripel said. Additionally, the prolonged drought of the 1990s depleted most of Patta Creek, nearly extincting native fish.
The Putah Creek Council, UC Davis and the city of Davis have filed lawsuits against the Water Agency and other cities in Solano County. Farmers were accused of using too much water and were told to use less. But they said that Montellol Dam, which created Lake Verisa, reduced water supply during the drought, threatening business and livelihoods.
Ten years later, the outcome of the lawsuit was the 2000 Pata Creek Accord. This allowed water flow throughout the year to prevent creeks from drying out and protecting their habitat. Since then, Solano County Water Agency, landowners, friends of Patta Creek Council, and other organizations have tried to restore the stream by adding water to increase the flow. A new “Stream Keeper” location has been created to monitor and manage the creek to coordinate with students and other stakeholders to restore the waters while monitoring and managing the creek.
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“When I arrived in Davis in 2017, there was a handful of salmon that had suddenly appeared in the fall a few years before that. It was by no means just a handful,” Ripel said. “And basically, what happened in my time in the last eight years was that the numbers keep increasing every year.”
People have discovered that almost all of them came from local federal hatch sites or state hatch sites. Generally, boy salmon move to the ocean to live as adults, then return to fresh water to spawn eggs.
In 2017, graduate student Lauren G. Hitt and other researchers began looking at the bodies found along the stream to see where the salmon were.
“We figured this out because the hatching field put a small tag on (part) of the fish to let us know where it came from. But we also did some otris microchemistry,” he explained as the ear-inducing bones are small ears that allow the fish to find balance in the water. “These little bones also place rings, just like the trees. So you can know how old they are. And the chemistry of the material basically tells you where they were in that year.”
Researchers monitored adult Chinook salmon in lower Patta Creek, each year between October and January. They conducted a survey from upstream to downstream, counting both live and dead salmon. Each corpse was recorded by GPS. They looked at earworms and observed them under a stereomicroscope to see the annual growth ring.
One of the challenges in restoring streams and increasing salmon populations is that they come from Lake Verisa and provide enough cold water that tends to warm as they flow downstream. In large reservoirs, cold water is present at the bottom while hot water is above.
“I think it’s a great success story of being able to put salmon in a landscape, but for agriculture, people, cities, and… for me, it’s a true California story,” Ripel said.
In the fall of 2024, researchers counted a total of 735 egg-laying adults in Puta Creek compared to the number of those in 2017.
Professor Andrew Lippel of UC Davis holds an adult Chinook salmon that was traveling through Pata Creek in 2023. David Ayers
Other regions are also working to increase salmon populations amid similar water usage competition.
Under the new plan, detours will be limited to 50% to 70% at certain times of the year.
The Modesto Irrigation district previously told the Epoch Times in an email that the plan would affect the local farming community and other people who rely on water. He said long-term impacts include lower affordability of locally grown foods, low-quality drinking water, and the burden of disadvantaged communities.
The San Francisco Utilities Commission, California’s third largest supplier, argued that the plan could cause users to run out of water.
Both sides are trying to find a balance between maintaining supply for farmers and urban users and protecting and promoting the wildlife environment.
