Changing tides in Santa Cruz water management seek to support fish populations in the San Lorenzo

The way water gets to Santa Cruz’s taps could change soon — and with it, the chances that steelhead trout and coho salmon can survive and thrive in the San Lorenzo River. Changes to the city’s water rules, a culmination of 25 years of work at the city’s water department, aim to provide a stable water supply for Santa Cruz residents and improve habitats for fish.

Coho salmon and steelhead trout once filled the waters of the San Lorenzo. Historically, the river supported the fourth-largest salmon and steelhead fishery in the state. Today, human activities have driven the species to critically low numbers. Salmon are listed as endangered and steelhead are threatened under the federal Endangered Species Act.

Pollution, warming waters and erosion from logging have made the region’s rivers uninhabitable for the fish species and caused their numbers to dwindle. Coho, in particular, are on the verge of extirpation from the Central Coast, meaning a complete disappearance of the species south of the Golden Gate.

Now, new regulations could help migrating fish by limiting the amount of water the city can pull from the San Lorenzo based on the time of year, the amount of water in rivers and the life cycles of fish species swimming in them.

Officials at the Santa Cruz Water Department hope that by restructuring water usage regulations and building new infrastructure to store and share water with other water districts, people and fish can share local rivers without either having to go thirsty.

Both steelhead trout and coho salmon are anadromous salmonids — fish that use freshwater rivers to spawn. In times of drought, low water levels in rivers can expose them to warm temperatures and even physically block them from moving upriver to spawn. This prevents the fish from reproducing normally, further threatening their populations.

The water coming from Santa Cruz’s taps has an important role in maintaining adequate water levels in local rivers.

The city of Santa Cruz currently uses almost 2.5 billion gallons of water per year and around 7 million gallons per day. A 2024 city report showed that 96% of the city’s water supply is surface water, coming directly from the San Lorenzo River and Liddell Creek. The San Lorenzo in particular contributed a majority, 61%, to meet the city’s water demands. The remaining 4% of water came from groundwater, pumped from wells and aquifers underground.

Water usage has become a more pressing concern recently due to changing weather patterns, said Heidi Luckenbach, water director at the City of Santa Cruz Water Department. She said in the past, less-intense storms over longer periods of time meant that rivers flowed more consistently throughout the year. 

Nowadays, shifts in climate have changed the picture. Luckenbach explained that annual rainfall has become concentrated in shorter bursts, so more of it runs off rather than saturating the soil. Without soil saturation, rivers are more prone to drying up in the summer. “Historically, we didn’t have to go on groundwater until June,” she said. “Now, we have to [start using groundwater] in May, because the flowing sources are drying up more quickly.”

To manage this, the city’s water department has drawn up a new plan to conserve water and protect salmon and trout without jeopardizing the reliability of taps around town. The plan is based on 25 years of work led by Chris Berry, watershed compliance manager for the Santa Cruz Water Department. 

The plan retools the city’s water rights — rules outlined by the State Water Resources Control Board that determine everything from when the city can use water to how much it can take from rivers and aquifers and where it can store it. Reworking the rules required the city’s water department to negotiate with the state agency.

The biggest change is that the city will be allowed to pull less water from streams and rivers like the San Lorenzo. The plan sets limits on the water that can be taken based on the time of year, the amount of water in rivers and the life cycle of fish species swimming in them. 

“That’s the basic premise — we have to leave more behind in the flowing sources,” said Luckenbach. The city’s water rights, which were most recently updated 50 years ago, were too outdated and restrictive to effectively protect fish, she said, because they didn’t take into account fish habitat, a changing climate or the city’s growth. 

To leave more water for fish without compromising water for people, the plan also allows the city to share more water and store it in aquifers and wells, which was previously not allowed under the city’s water rights. This involves filling underground wells with surplus water during rainier months and then drawing from them as needed in times of drought to decrease demand on rivers, Luchenbach said.

The city is currently modifying one well in town to store water and has plans to have four storage wells working by the end of 2029. Retrofitting each well is expected to cost $6 million, which will be paid for by ratepayers.

The new water rules also allow Santa Cruz to share water with other water districts, like Scotts Valley and Soquel Creek, via interties — pipeline systems that connect distinct public water systems. Currently, Scotts Valley and Santa Cruz are constructing a 2-mile pipeline to connect their water systems, funded by a $6.5 million grant from the state Department of Water Resources. The project is expected to be finished in 2026 and will be the final link connecting all public water agencies from La Selva Beach to the San Lorenzo Valley.

Interties have historically been used in times of emergency, such as fires and extreme droughts, to provide water reliability to cities and towns in need. Now, officials from the Scotts Valley, Soquel Creek and Santa Cruz water agencies are working on agreements to share water more regularly, outside of emergencies.

While the Santa Cruz Water Department has no specific goal for how much of the city’s water supply will come from aquifer and intertie sources, officials expect this new infrastructure will provide more flexibility to draw on alternative water sources, depending on the season, river levels and the needs of threatened fish. 

With $37 million worth of separate salmon habitat restoration and monitoring work planned over the next three decades, Berry hopes these strategies will provide big upsides for fish conservation.

“The [new rules] allow us to be a little bit more creative about how we use water,” said Berry, who will be responsible for implementing the conservation plan for the next 30 years, “not only to benefit our customers and the regional water resource management, but also address the fisheries issues as well.”

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