Helicopter to be seen around parts of Valley for geological study

FRESNO, Calif. (KFSN) -- The sight of a low-flying helicopter on the west side of the Valley has caused many people to pause.

The US Geological Survey has a large hoop flying beneath the chopper.

"On that hoop is a geophysical sensor," says USGS Research Scientist Lyndsay Ball. "That sensor collects information about below-ground resistivity."

The current flows better if there is more salt in the water.

Ball says not only is this high-tech survey monitoring oil and gas underground, but it is also measuring groundwater.

"Where the water table is -- we're also more specifically looking at groundwater salinity, or how salty the water is," she said. "That will give us an understanding of where there's fresh, brackish and saline groundwater in these areas."

It's important information after three years of drought.

The helicopter will buzz along areas near Kettleman City, Coalinga, even Kern County, for this state project.

Individual well samples can be taken to see how much the water table has fallen in certain areas, but that doesn't tell the whole story.

This survey will connect the dots between wells.

"Just like you said, there's a lot of times you don't know the groundwater flow," Ball said. "You don't know the connectivity in the aquifer. This data will give us more of an understanding of where there are clay layers."

Ultimately, the data will reveal a high-resolution view of the underground geologic structure and groundwater conditions.

The Department of Water Resources has used similar technology for SGMA - the Sustainable Groundwater Management Act.

This project is focused on measuring groundwater conditions in areas of oil and gas development.