Method could help enhance water storage


Issue Date: April 20, 2016
By Kate Campbell
With Coyote Valley Dam reaching near its storage capacity in late March, the U.S. Army Corps of Engineers releases water, above, to create flood space in Lake Mendocino. Flood control continues to be a priority as scientists and engineers look at ways to better manage surface water to meet increasing demand.
Photo/J.D. Hardesty, U.S. Army Corps of Engineers

A study underway in the Russian River watershed is looking at ways to ensure flood safety while improving water supply reliability for farmers, fisheries and communities. Using a method called "forecast informed reservoir operations," or FIRO, the study is testing an evolving strategy that uses advances in technology and science to forecast weather and watershed conditions more accurately, in order to anticipate runoff into storage.

The study is being watched closely by managers of other reservoirs, to see if the technique could be applied more widely in California and the West.

Water managers in Sonoma and Mendocino counties say using and interpreting real-time information may help pinpoint when to retain or release water from Lake Mendocino on the Russian River. Using modeling, advanced forecasting tools and improved information systems, experts are testing the approach in operating Coyote Valley Dam, which until recently was managed according to a 1959 control manual specifying reservoir elevations to control downstream flooding.

"We're at the beginning stages of trying to figure out how we can use data to operate the dams more effectively," said Mendocino County winegrape grower Janet Pauli, who has been closely following the FIRO discussions. "Instead of using a rigid operating manual, we're moving to more forward thinking to take advantage of emerging science and technology."

She said it will take time to assess the reliability of FIRO. The U.S. Army Corps of Engineers, for example, must be completely convinced that, if there are changes to operations, it will be safe for people downstream.

As with many of California's 1,400 dams and reservoirs, the structure and the way it's operated have taken on added responsibilities. The dam's first purpose when it was built was for flood control, but it has become increasingly important for agricultural and municipal water supplies, releases to protect endangered species and recreation.

Tamara Alaniz, general manager of the Russian River Flood Control District, said the district is encouraged by the corps' decision to "deviate from the historic rule curve" used to manage storage and releases from Coyote Valley Dam. Alaniz said that could allow "greater flexibility and a more stable water supply for the Ukiah Valley region, especially during dry and drought years."

Pauli said the U.S. Geological Survey is putting together models to track how water moves through the Russian River watershed, which drains much of Sonoma and Mendocino counties and is home to endangered coho salmon, plus threatened chinook salmon and steelhead trout.

Using technology and forecasting capability, experts think it may be possible to increase water supplies in Lake Mendocino by an average of 6,000 acre-feet a year, and possibly more, as more is learned. Although that is not a huge amount of water when compared to statewide reservoir capacity, Pauli said it could be enough for farmers in the Russian River watershed to produce crops during drought, rather than having their water rights curtailed as they have been in recent years.

Michael Anderson, state climatologist with the California Department of Water Resources, is a member of a multi-agency steering committee looking into the FIRO strategy. He said the strategy aims to use increasingly more accurate weather forecasting to retain water in a portion of flood-control space in reservoirs, when it's safe to do so.

One risk, he said, is the impact of atmospheric rivers—storms that can hit the state, stall and cause serious flooding. On average, about 30 percent to 50 percent of annual precipitation in West Coast states occurs in just a few of these atmospheric river events, which are distinct from ocean warming and cooling trends commonly called El Niño/La Niña.

The multi-agency committee investigating FIRO includes scientists from the National Oceanic and Atmospheric Administration, Scripps Institution of Oceanography, the Army Corps of Engineers, DWR and the U.S. Bureau of Reclamation.

The committee is co-chaired by Sonoma County Water Agency Chief Engineer Jay Jasperse, who said it plans to conduct a FIRO "proof-of-concept" assessment using Lake Mendocino as a model, including short-term steps and long-term research. Implementation of any operational changes will be done in increments, he said, as science evolves and adjustments prove to be safe and beneficial.

Experts say the project has the potential to demonstrate ways to transfer the approach to operation of other dams and reservoirs. To what extent the approach can be applied is uncertain, but the implications are drawing national attention: The Coyote Valley Dam project was highlighted this spring during the White House Water Summit in Washington, D.C., as a project offering promise in helping meet water supply needs.

In addition, NASA announced formation of an agency-wide Western Water Applications Office, based at its Jet Propulsion Laboratory in Pasadena. Officials said the office will open this summer and support development of water supply applications from satellite observations and airborne technologies to better meet the challenges of drought, flooding, declining snowpacks and falling groundwater levels across the West. Data will be available to weather forecasters working on the Sonoma-Mendocino FIRO project.

The strategy being explored and tested at Coyote Valley Dam also fits into a larger discussion about "smart dams": infrastructure that is modified or built to provide a variety of benefits. In addition to water supply, flood control and hydroelectricity, water managers are looking at water infrastructure that's capable of responding to changing climate conditions, while enhancing habitat, species protections, water quality and expanded recreational opportunities.

Danny Merkley, water resources director for the California Farm Bureau Federation, said FIRO and smart-dam technology could add to the flexibility of existing and new surface-storage projects.

"We recognize there's still much to learn about these methods," Merkley said, "but we're hopeful this strategy can be used to maximize storage in current surface reservoirs and that new projects will also benefit from what is learned."

Online information about FIRO is available at http://cw3e.ucsd.edu/FIRO/.

(Kate Campbell is an assistant editor of Ag Alert. She may be contacted at kcampbell@cfbf.com.)

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.