Time to Review Some Dam Decisions?

Here are 181 Candidates to Seriously Consider

On October 22, 2014 the UC Davis Center for Watershed Sciences identified 181 dams in California that are “high-priority” candidates for reallocating water flows, to protect the health of related watersheds and sensitive species—in keeping with the state constitution’s “beneficial use of water” section, the public trust doctrine, both state and federal endangered species acts, and Section 5937 of the California Fish and Game Code, a rarely enforced state law more than 100 years old.

In their technical report Assessing Flows for Fish Below Dams: A Systematic Approach to Evaluate Compliance with California Fish and Game Code 5937, Theodore E. Grantham and Peter B. Moyle acknowledge reasons most dam owners haven’t complied with the Fish and Game requirement that they release enough water “at all times” to keep fish “in good condition.” There are well over 3,000 dams in California—some federal, some state, some privately owned—and enforcement would carry with it financial and political costs that most leaders prefer to avoid.

“This drought year, as in those past, California water regulators have given away to cities and farms some river flows critical to fish and wildlife,” say Grantham and Moyle in the online summary posted on the California Water Blog. “It’s a dicey tradeoff considering most of our native fishes are in trouble even without the drought.”

Yet citizen lawsuits—to provide healthy water flows for the San Joaquin River, Putah Creek, and a handful of other waterways—have succeeded, whether or not these represented the most critical need statewide.

Which led to the question that prompted the UC Davis watershed report: “If Section 5937 were more broadly applied to improve fish flows, which dams should get the focus of attention?”

To come up with an answer, the Center “developed a systematic and science-based approach for evaluating and targeting dams for potential enforcement,” a detailed research protocol soon to be formally published in the peer-reviewed Oxford Journal BioScience, published on behalf of the American Institute of Biological Sciences.

Adequate for most of us, though, is the shorthand explanation of how they evaluated dams for “evidence of inadequate downstream flows for sustaining healthy fish populations,” information that allows managers and policymakers to perform “triage”—to focus their efforts where the need is most urgent.

First, researchers identified dams subject to fish flows law, “those on relatively large rivers and streams with enough storage capacity to change the timing and magnitude of river flows.” These dams were then reviewed for changes in downstream natural water flow that could harm fish. Finally, the impact of altered flows on fish was assessed, to flag dams in watersheds where fish are imperiled.

Using these admittedly coarse “filters,” the UC Davis researchers evaluated 753 California dams and identified 181—almost 25 percent—as “high-priority candidates for Section 5937 enforcement.”

Letting It Flow

According to Grantham and Moyle “there is ample evidence that many large California dams likely fall short of providing adequate flows to keep fish in ‘good condition.’” More than 80 percent of California’s native fish are at risk of extinction, they say, if present trends continue. How we manage dams is the key factor for their survival.

Removing dams entirely is one possible solution when below-dam flows aren’t enough—or are too warm—to support healthy fish and wildlife populations, though the report doesn’t address the whys and wherefores of any action. Yet it’s not the only possible approach. Releasing water at critical times can keep fish healthy during crucial periods in their life cycles.

The researchers believe “strategic implementation of Section 5937 could provide reasonable protections of California’s dammed river and streams.” Such implementation would have to be “systematic and transparent,” from monitoring and evaluating water flows to mitigating any environmental effects.

And, the report points out, being identified as “high priority” doesn’t necessarily mean a particular dam violates Section 5937: “That determination requires a closer, on-site investigation of dam operations and their effects on fish.”

Still, “enforcement” candidates reasonably close to home here in Northern California include some dams whose removal—even the very thought of their removal—would cause gasps of disbelief: Folsom Dam on the American River, in Sacramento County, for example, and Anderson-Cottonwood, Keswick, and Shasta Dams on the Sacramento River, in Shasta County. Other notables include Dwinnell Dam (Shasta River Dam) on Shasta River, in Siskiyou County, and both Lewiston Dam and Trinity Dam on the Trinity River, in Trinity County.

(Dwinnell, though, is no longer a “high priority.” As the result of a lawsuit—dam owner Montague Water Conservation District has agreed “to release significantly greater flows and to take other measures to protect fish down stream.”)

Others candidate dams close to home include Black Butte Dam on Stony Creek, in Tehama County; Englebright Dam on the Yuba River, in Yuba County; La Grange Dam on Tuolumne River in Stanislaus County; New Hogan and New Melones Dams on the Stanislaus River in Calaveras County; Conn Creek Dam in Napa County; and Warm Springs Dam on Dry Creek, in Sonoma County.

Then there’s Boca and Stampede Dams on the Little Truckee River, in Sierra County; Donner Lake Dam on Donner Creek, in Nevada County; and Lower Scotts Flat Dam on Deer Creek in Nevada County.

Truly stunning to contemplate, however, are the many Southern and Central California dams the report identifies as top priorities, the great majority of those 181 enforcement “candidates.

Long Valley Dam on the Owens River, which saves water for transport to Los Angeles, is one of those candidates and a case study included in the report. Several species of fish native to the Owens River, including the Owens tui chub, are affected by this dam below Mono Lake in the Owens Valley.

If you haven’t already taken a look, download the UC Davis report here and read up on its results and research methods. Neighborhood fish will be grateful.