“More monitoring of these critical streams is needed to protect these vulnerable species,” Andrews said. “If we maintain the status quo, and if we don’t know how much water is in rivers and streams, we are essentially dooming some of our freshwater species.”

In another recent report, researchers with the Public Policy Institute of California assessed the dire threats to freshwater biodiversity in the state. Studies have found that about half of California’s native aquatic species are highly vulnerable to extinction this century, and the researchers said with climate change accelerating, the state needs to quickly adopt new types of conservation plans and approaches to save species.

“There are no protections in place for the vast majority of species that we could lose,” the researchers wrote. To reverse the decline in freshwater ecosystems, they said, business-as-usual management approaches likely won’t be successful and “bold, perhaps even risky innovations in policy and management are needed.”

While the institute’s proposals for “climate-smart” conservation plans outline strategies for reversing declines in species, the UC Berkeley researchers focus on the critical role of stream-flow monitoring data for making decisions about managing water and protecting ecosystems.

Among other findings, Grantham and Andrews determined that only about 9% of the state’s 817 large dams have an active gauge either upstream or downstream, and that about 29% of watersheds with the highest diversity of aquatic species are monitored.

They found that there are especially low numbers of stream gauges in watersheds that are minimally disturbed by people. In areas that are mostly untouched by nearby development or diversions, less than 1% of streams are covered by an active gauge.

This shows a particular need to expand flow measurements along these streams, Andrews said, which are where “we can start to see the fingerprint of climate change on the hydrology.”

Their analysis also found regional differences, with more gauges on streams that are heavily used for agriculture in the Central Valley, and significantly less monitoring in other areas, such as streams in parts of the Sierra Nevada, Southern California, the North Coast, the North Lahontan region and the Scott and Shasta rivers in the Klamath River basin.

These differences in regional data gathering are a significant problem, the authors said.

“If we’re missing certain regions, we can’t necessarily speak to the holistic impacts of climate change on California’s waterways and on water resources available for the economy, for cities, for farms,” Andrews said. “What’s happening on the North Coast is not going to be the same thing as what’s happening in Imperial Valley, is not going to be the same thing as what’s happening in Monterey. And so if we don’t have gauges in all of these places, we’re really flying blind.”

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