Big Valley Basin (Kelseyville/Lake County) Saturday, November 13
Ukiah Valley Basin (Mendocino County), Sunday, November 14
Santa Rosa Valley/Santa Rosa Plain Monday, November 15
Napa-Sonoma Valley/Sonoma Valley Wednesday, November 17
Source: Ministry of Water Resources
If you think that in the next few days you will see a very large, very strange object flying above your head, that is not your imagination.
The State Department of Water Resources will launch a specially equipped helicopter in the area this weekend. The helicopter will fly at low altitude and hang a 100-foot-wide hoop to send electromagnetic signals to the earth. The signal will bounce and be recorded on the onboard instrument.
These flights are part of a three-year effort to collect data on the geological structure and characteristics of major groundwater basins around California to strengthen sustainability planning and focus on future groundwater recharge efforts.
After working in areas further north in California earlier this week, the helicopter is expected to fly over the Great Valley Basin in the Kelseyville area of Lake County on Saturday, followed by the Yukia Valley Basin in Mendocino County on Sunday. .
Investigators are tentatively scheduled to arrive in Sonoma County on Monday and will fly to the Santa Rosa Plain, Petaluma Valley and Napa Sonoma Valley in the next two to three days.
According to the State's 2014 Sustainable Groundwater Management Act, each basin is identified as a medium or high priority groundwater basin.
Although the time required to synthesize and interpret data from the airborne electromagnetic survey program means that it will not be able to help the first round of local groundwater basin planning due to the state in January, the AES data will be worth five years and will be drafted and updated in the future.
The resulting data and hydrological mapping should also contribute to the development of engineering projects such as flood management, water delivery, and infrastructure.
Jay Jasperse, chief engineer and director of groundwater management at Sonoma Water, said: "We are very pleased that the state government can step in and help us because it will help us improve our plans."
According to Katherine Dlubac, an engineering geologist and AES project manager at the Ministry of Water Resources, the survey technology was developed in Denmark and tested in California as part of a pilot project, although it has also been used domestically and internationally.
She said it is completely safe, and the electromagnetic field exposure produced is roughly the same as that of a normal toaster or stand mixer. "It's really very little," Dlubac said.
However, it carried an awkward load — a large hoop about 100 feet in diameter suspended 100 feet below the plane, she said — so the flight path is usually outside of densely populated areas.
However, the bigger reason is that highly urbanized areas will produce too much electromagnetic noise, which interferes with data collection. Metal structures, pipelines, railway lines and other infrastructure make the exercise meaningless.
Dlubac said the electromagnetic signals emitted by the onboard instruments collect information about conductive and resistive materials underground. This is used to help define the location of coarse-grained materials (such as sand and gravel) that may allow water to filter, and fine-grained silt and clay that inhibit water flow.
Jasperse said that electromagnetic surveys can also help map fault lines, and "can also help you understand in a broad sense the indications of saline groundwater-where there is salt water-which is particularly important in Sonoma Valley and Petaluma Valley. Because of San Pablo Bay."
"This technology can provide a lot of good information," he said.
Dlubac said that the plane flies in a grid mode to assess the spatial extent and depth of different underground characteristics and fill in the gaps in the data. This depends largely on decades of observation by drillers and recent hydrological modeling.
“Now we have more continuous data, which provides us with more three-dimensional understanding of these layers,” Dlubac said.
This $12 million project is funded by Proposition 68, a $4 billion general obligation bond approved by voters in 2018 for drought, water, parks, climate, coastal protection, and outdoor access projects.
You can contact full-time writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.
Big Valley Basin (Kelseyville/Lake County) Saturday, November 13
Ukiah Valley Basin (Mendocino County), Sunday, November 14
Santa Rosa Valley/Santa Rosa Plain Monday, November 15
Napa-Sonoma Valley/Sonoma Valley Wednesday, November 17
Source: Ministry of Water Resources
Environment and Climate Change, Press Democratic Party
I am in awe of the breathtaking nature of Sonoma County and am very grateful to live in this spectacular area we call home. I am also surprised by the expertise of our community and the commitment to protecting the land, waterways, wildlife and residents. My goal is to improve understanding of the problem, find hope and help us all deal with the environmental future.
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