Study indicates no overdraft from Scott Valley wells


Issue Date: October 17, 2012
By Kate Campbell

An innovative groundwater monitoring program in Siskiyou County is already yielding valuable results.

The underlying concern in the water monitoring activities is addressing assertions that crop irrigation causes water levels in the Scott River to drop, affecting fish. In dry years, the snow-fed watershed experiences dry sections in streambeds during late summer.

In partnership with researchers from the University of California, Davis, Scott Valley farmers have been collecting data from 36 wells since 2006.

The information has helped answer a key question: Is the valley's aquifer being overdrafted?

The UC researchers say no. The data show the Scott Valley is not in an annual overdraft situation, meaning groundwater levels are not declining during years of normal precipitation and recharge.

Scott Valley growers use water-efficient irrigation systems to grow alfalfa and grain crops, as well as provide pasture.

Scott Valley farmer Jim Morris, a member of the county groundwater advisory committee, explained that scientific evaluation of groundwater levels represents only part of the information needed to meet requirements of a state-mandated Total Maximum Daily Load for temperature levels in a watershed that serves agricultural irrigators and supports several salmon species.

"We're working our way toward a better understanding of the role irrigation plays in groundwater levels in the watershed," Morris said. "In doing this, we're taking a proactive stance in water use and conservation."

Morris, a past president of the Siskiyou County Farm Bureau, monitors levels in the well on his own ranch and reports the data.

"We have a lot at stake in this," he said. "My intent is for my family to continue farming in the Scott Valley for at least the next 150 years. We don't want to tear up what we have. I want to better understand the system so we can farm sustainably using good science into the future. I want to know the truth."

The county adopted the water monitoring plan in 2008, with the goal to establish a three-phase "road map" for monitoring and management that could be conducted during the next 20 years, as funding is available.

The Scott Valley community, including farmers, ranchers and conservation groups such as the Scott River Watershed Coalition, collects data on well levels and provides it to researchers who are building a groundwater model. The model can be used to better manage water resources under a variety of scenarios—wet, dry, and changes in climate and cropping patterns.

"I feel I am going above the call of duty by volunteering to modernize my irrigation system for maximum efficiency at my own expense," alfalfa grower Tom Menne said.

Menne has installed center pivots to sprinkler-irrigate alfalfa fields, replacing less-efficient wheelline sprinklers, and has automated a dozen systems, which he said has increased his water efficiency by more than 20 percent.

Regional water board officials call the hydrology of Scott Valley complex, and say UC researchers have made significant progress on developing the model to gauge how the watershed will respond under a variety of environmental circumstances.

Bryan McFadin of the North Coast Regional Water Quality Control Board said the board "expects the groundwater model (UC) is developing with the county and the community's assistance will be a powerful tool for evaluating opportunities to manage the resource to improve water quality and provide a reliable water supply."

Rancher Preston Harris said he believes the community has "an opportunity to do some remarkable things to manage and enhance our groundwater in Scott Valley."

He said partnerships developed with UC Davis, Siskiyou County, the Scott Valley Groundwater Advisory Committee, the watershed coalition and government agencies will play a "huge role" in the success of the study and in developing effective models.

Siskiyou County Supervisor Marcia Armstrong said a Scott River water rights adjudication has adjudicated a portion of the groundwater and there have been lawsuits claiming the groundwater has not been managed in compliance with the state's public trust doctrine, as well as objections from the region's Native American tribes. The area also has one of the state's first active water trusts, which benefits streamflow through forbearance agreements and voluntary leases with agricultural water users.

"We're creating a number of avenues for the community to step forward and take charge of their own groundwater planning," Armstrong said.

Online information on the Scott Valley Community Groundwater Study is available at http://groundwater.ucdavis.edu/Research/ScottValley/.

(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.