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California Dams May Be Key to Rescuing Fish

by
Scope Correspondent

If you want to save California fish, give them water say the experts. In an effort to save fish populations threatened by the drought, a new study identifies dams where water flow could potentially be increased to help certain fish thrive. In a paper published in the October 15th edition of BioScience, researchers at the University of California Davis’ Center for Watershed Sciences identified 181 California dams that could adjust water flows in order to restore populations of fish that rely on specific flow patterns to survive.

One example is the salmon, says Theodore Grantham, the study’s lead author. Salmon rely on heavy winter water flows from rainfall to trigger upstream migration. But big irrigation dams store up this water, so salmon habitat below the dam has a much lower flow level than is natural.  “Those low flows can prevent the migration of fish or can create other problems,” says Grantham.

In addition to identifying “high priority” dams that currently have water flows that are potentially harmful to fish, UC Davis also created a statewide database that logs information on each dam’s location and how much water it stores. Grantham hopes that both the list and the database can help state regulators and water management agencies target their attention and resources to the waterways that need it most.

But increasing water flow in a drought season is tricky. In 2006, former governor Arnold Schwarzenegger referred to the political battle over California water allocation as a “holy war in some ways” according to the LA Times. Now, more than three years into the drought—and 11 months after Governor Edmund “Jerry” Brown declared it an official State of Emergency—the battle between farmers, municipalities, and environmental agencies all competing for the ever-dwindling water supply is even more contentious. The fact that it’s hard to predict when the drought will end makes water allocation decisions even harder says Mike Wolder, a supervisory wildlife biologist with the Sacramento National Wildlife Refuge Complex, an organization which manages approximately 35,000 acres of land in the Sacramento Valley.

“Our reservoirs are incredibly low right now…if we [release] too much, there’s not going to be anything left and there’s sure as heck not going to be anything left for next year,” he says. “That’s where the water agency folks have an extremely tough job.”

Issues of politics are complicated further by vague state laws—California Fish and Game Code requires dam owners and operators to allow enough water to keep fish “in good condition” without defining what that means. This makes pushing the case for increasing water flows across multiple dams challenging.

Some major changes have already been made, though not without pushback. In August of 2013, the Bureau of Reclamation increased water flows from the Lewiston Dam on the Trinity River to help boost Chinook salmon populations. Arguing that the water should be reserved for agriculture, The Westlands Water District and the San Louis & Delta-Mendota Water Authority sued to prevent the releases, but were overruled by a federal judge. This past October, the Bureau also increased flows from the Iron Gate Dam on the Klamath River in northern California to diffuse a parasite outbreak. But the state’s biggest water flow project won’t be officially complete until 2016. California is currently in the midst of an $84 million initiative to tear down the San Clemente Dam. The project is estimated to open up access to 25 miles of spawning habitat for endangered steelhead trout.

Adjusting dam flows may temporarily solve California’s H2-woes, but it doesn’t decrease overall water use. Water-saving efforts are in effect—Californians used 11.5 percent less water this August versus last August according to recent data from the State Water Resources Control Board—but conservation alone won’t solve the crisis says Brian Fuchs, a climatologist with the National Drought Mitigation Center at the University of Nebraska-Lincoln.

“In a short-term drought, conservation will gain you a lot of ground,” he says. “…at some point, the conservation techniques that are being implemented and are being used are just not enough by themselves. We have to start looking at other ways and means of decreasing water use.”

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