California enacted the Sustainable Groundwater Management Act in 2014, in response to the then years-long drought to manage state groundwater supplies. The law calls for the sustainable management of groundwater basins.

As Siskiyou County slips back into severe drought, members of Siskiyou County’s Groundwater Advisory Committees met last week to continue drafting groundwater management plans as conservation groups, farmers and other special interest groups brace for another dry summer.

California enacted the Sustainable Groundwater Management Act in 2014, in response to the then years-long drought to manage state groundwater supplies. The law calls for the sustainable management of groundwater basins. In the context of groundwater, the state defines sustainability as managing water resources to meet the state’s current environmental, residential and agricultural needs while not impacting the ability of future generations to also meet their needs.

SGMA calls for the formation of Groundwater Sustainability Agencies to monitor the amount of water pumped out and put back into a basin.

The Siskiyou County Flood Control and Water Conservation District is the GSA for Scott and Shasta Valley basins. District meetings are held during the regularly scheduled Board of Supervisors meetings.

Over-drafted basins in California’s Central Valley have seen land subsidence, seawater intrusion, and drastically lowered water tables. The ground water basins in Siskiyou County are in better shape. Considered moderately over drafted, the Siskiyou County basins are required to have a plan in place and approved by the Department of Water Resources by 2022.

Each month, county GSAs have been meeting to craft guidelines on water quality, data collection and ground water modeling to meet the 2022 goal. April’s meeting focused on modeling surface and groundwater interactions. For the Scott Valley, modeling the impact of ground water extraction on surface water is fairly straightforward, said Laura Foglia, a professor at UC Davis and the principle scientist assisting the Siskiyou County GSA in producing a plan. The Shasta Valley is another matter. Unlike the simple alluvial basin that is found in the Scott Valley, where the sub surface sediment holds water uniformly and predictably, the Shasta Valley’s volcanic legacy created lava tubes and other underground passages and fissures that move and hold water in unpredictable ways.

“The Shasta model is the hardest I have ever worked on,” Foglia said. “Understand that in Shasta Valley there is an impact on springs. We know the geology is complex, not as linear as in most other places. We need to understand through local knowledge how irrigation has impacted [each part of the valley].”

The Scott River is fed by streams and interacts with the ground water in predictable ways. Pumping water from wells will lead to a corresponding drop in the water table, explained Foglia, and winter rains will recharge the groundwater supply in equally measurable ways. The Shasta River, on the other hand, is primarily fed by springs.

“You don’t see seasonality like you do in other basins,” said Foglia. “The groundwater has an impact on springs, but how to account for that? Maybe the springs are discharging less [during irrigation]. It is not a linear simple decision. The data and model will have to work together.”

To get the necessary data, Foglia and the other scientists tasked with modeling the watershed are relying on historical data, test wells and public input. Understanding how the water table fluctuates throughout the year in different parts of the valley will be crucial to getting an accurate idea of the water in the ground.

“It’s a sensitive matter to discuss,” said Siskiyou County Natural Resources Specialist Matt Parker about tracking water use in the valley. Parker points out that ultimately SGMA is there to give county residents control of how water is managed to meet the state guidelines. The end goal of the state and the county are the same, to provide enough water for the residents, farmers and wildlife. “How can we use the model to help us better understand the watershed?”

SGMA does not trump water rights, Parker emphasized, but understanding flow contributions of the springs into the river is important to managing the valley and for possible groundwater recharging projects. Keeping cold water in the stream can be done while honoring water rights. Upper watershed management will be important in the long term too, he said, as ways of adjusting the amount and quality of water in the system.

Water needs in the Shasta Valley revolve around providing safe, clean drinking water for residents; providing an affordable, reliable supply of water for farmers; and providing cold, oxygen-rich water in the summer months for fish and other instream wildlife. Those cold-water springs have historically been diverted for irrigation, explained Eli Scott, Scott and Shasta Watershed Steward. Scott, who represents the North Coast Regional Water Board, said that maximizing the flow of cold spring water into the main stem of the Shasta River is important to fish health.

“Flow is the main knob you can turn,” said Scott. Temperature and dissolved oxygen are crucial to juvenile salmonids during the summer. “Having good flow in summer minimizes stagnate water.”

By working with farmers, Scott highlights how infrastructure improvements can increase cold water flow into the Shasta River, minimize warm tailwater coming off irrigated fields, and provide places for impounded water to get rid of excess nutrients. Pointing to a study on Shasta Valley’s Big Springs Ranch, which was acquired by The Nature Conservancy and sold to the State of California, Scott showed the number of days with critically high water temperature dropping by up to 75%.

Data collection from wells will begin again in June. As 2020 shapes up to be one of the driest on record, Foglia doesn’t think that will affect the monitoring process. Well data on some of the wells in the model go back into the 1990s, she said.

“With the dry year coming up we can use that info to support better management practices,” said Foglia. Monitoring now can show how pumping can alter flow in extremely dry years. “We have data to start understanding processes.”

While the Siskiyou County GSA and scientists from UC Davis work on how to measure the water in the ground, what comes down out of the sky is out of their control. Regardless of how water is managed in the Scott and Shasta Valleys, the climate is the ultimate driver of water security. The current severe drought in Siskiyou county is part of a multi-decadal dry spell that is part of one of the deepest megadroughts in the region for more than 1,200 years. Using tree rings from a 9-state area across the west, scientists from Columbia University measured soil moisture going back into the 16th century. Droughts are a recurring feature of California’s climate, but the one currently underway is unprecedented in modern times. The four-year period between fall 2011 and fall 2015 was the driest since recordkeeping began in 1895.

In Siskiyou County, this past January and February were two of the driest winter months on record, with some parts of Siskiyou County receiving no precipitation at all in February. High temperatures have compounded the problem, with 2014 and 2015 being the two hottest years in the state’s recorded history.

Records continued to be set last year, with September 2019 coming in as the second hottest on record for the county. The lack of water has been particularly hard on the agriculture sector. Most farming in California depends on irrigation, which accounts for about 80% of the state’s human water use. However bad the lack of water has been for farmers, the lack of water and the rising temperature has been detrimental to fish populations in the Shasta and Scott Rivers. Balancing the needs of everyone and everything going forward will be a difficult job for the local agencies tasked with the job.

“As the community has experienced in previous drought years, these dry conditions affect all aspects of the community - economic, human and ecological,” said Scott Valley River Watershed Council chairwoman Betsy Stapleton. “We applaud the efforts being undertaken to proactively address the dire situation by the County, towns, agricultural and individual water users.”

For information on upcoming SGMA meetings, visit the county’s website at www.co.siskiyou.ca.us.