The use of the airborne electromagnetic data to assess the connectivity of river water and groundwater in the SJV (Prentice)

Seminar Discussions
1

Becca Prentice’s seminar talk from April 15, 2026.
Please login and post any questions you have for Becca here.

:television: Seminar Recording (Passcode: 2Pn%?GGE)
:bar_chart: Slides

2

Given the agricultural intensity of the region (and therefore economic significance), is there a connection between productivity or output from the sector and the connectivity of the sub-basins? Are catchments (sorry, more UK terminology) with no connectivity to groundwater more susceptible to water shocks and resultant economic (agricultural) shocks?

3

Asking for clarification - I think you define “connected” as potential to recharge. But ICONS defines likely connected as the water table is likely in contact with the river. Your high level of sand and gravel does not say the water table is connected to the river, but you do say there is potential to “connect” through percolation/recharge.

4

Forgive a second question - going back to my own PhD research here! Have you considered (or is there potential to consider) supplementing this extremely interesting work on pathways from surface to subsurface with the application of isotopic or alkalinity tracers to determine residence times and the duration water sits in storage?

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from Bill Eisenstein (River Partners) - can we use the AEM data to look deeper and start thinking about the impact of pumping from various levels (confined, unconfined)?

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I have never looked into the relationship. I think historically, people drilled deeper wells into and tapped into the confined aquifer when they needed more water. However, it would be interesting to look into this and see if there are any correlation between low connectivity according to the AEM data and unproductive agricultural fields.

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7

Yes! This is definitely something that we can do. With the AEM data we can image up to 300 m beneath the surface. InSAR (a satellite that measures surface deformation) is also a great way to look at groundwater storage changes in the confined aquifer. Sylvia will be presenting this later this quarter (I think May 13th)!

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Yes, this is a great point! There has been a lot of geochemistry work looking at sources of groundwater from LLNL. It would be great to incorporate this.

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