Citation by Fred M. Phillips
I am both honored and greatly pleased to introduce Professor Kip Solomon as the 2024 recipient of the O.E. Meinzer Award in recognition for developing the 3He/4He method for groundwater dating.
Kip Solomon was a pioneer in developing the sampling and analytical techniques to transform 3H/3He dating from a dream to reality. In doing so, he fundamentally changed our ability to quantify the age and residence times of the subsurface water stores on which billions of people worldwide rely. The techniques that Professor Solomon pioneered provide independent metrics that can be used to construct and evaluate physical hydrological models underlying sustainable yield calculations, contaminant transport, and resilience to climate change. He has also used 3H/3He dating to demonstrate that the process of runoff generation is much more complex than was thought even a decade ago, involving intricate three-dimensional flow paths and widely variable, and often quite long, residence-times.
The method was initially proposed in the 1960’s, but was not analytically feasible at that time, or for a long time after. It was not until Solomon’s landmark 1993 paper that 3H/3He graduated from being a ‘wish and a hope’ to the status of a solidly established dating technique. Since 1993 Kip has forged ahead with an ever-increasing range of impressive applications for the method. The 3H/3He method is amazingly powerful.
In addition, for decades, Kip and his laboratory have served our community through analyses, interpretation, and training in these groundbreaking analyses.
The advent of 3H/3He dating can be likened to the opening of eyes formerly blind to now being able to see the quantitative dynamics of groundwater systems. Thanks so much, Kip!
Response by D. Kip Solomon
Thank you, Fred, those that supported my nomination and the Hydrogeology Division. As a graduate student I attended this meeting in 1993. I still remember Neil Plummer being honored with the Meinzer Award for his work on using CFCs as a groundwater dating tool and geochemical modeling. Neil, Fred and the many other recipients of this award have been my professional idols, so for me to receive this award is an extraordinary honor.
The first published measurements of 3H/3He age in groundwater occurred in 1988 in two simultaneous independent papers. However, I am aware of groundwater measurements before our first paper. The early attempts collected samples from a transect of wells that were approximately located along a flow line with the expectation that water would get older in the downstream direction. The results were at odds with this expectation in part because the wells were screened over large intervals with depths that were not considered. This brings me to one of several suggestions I have for young hydrogeologists. How you collect samples matters! Screened intervals, pumping rates and histories, purging, etc. matter a great deal especially when it comes to environmental tracers.
The idea to apply the 3H/3He method to groundwater first came to me at a professional meeting. Going to meetings is a good thing as is attending sessions that might be outside of your experience; this can lead to new ideas as was the case for 3H/3He groundwater dating.
We have powerful models these days and I am a big proponent of these. But they need to be informed by carefully and thoughtfully collected data. In work that I have done with colleagues Dave Genereux, Troy Gilmore and numerous amazing students in the coastal plain of North Carolina and the Sand Hills of Nebraska, leave me amazed at the remarkably steep gradients in apparent groundwater transit times we observe across a streambed. My intuition and some modeling said that dispersion should mix everything together, but that is not what we observed. Like going to meetings, making measurements is important.
My enthusiasm for groundwater dating stems from a simple idea. The mean “age” of water at a point in the subsurface contains information, albeit convoluted, from the entire upstream flow path. In hydrogeology we suffer from a lack of monitoring points in a geologic world that is so complex. Integrating tracers such as 3H and 3He are powerful tools that I hope are used more and more in the future.
Many of the seminal papers I read in the early years of my research and education were single or dual authored. That has changed. Our science has become very collaborative, and I have benefited from many mentors, colleagues and students. I don’t know why I have been so lucky to have such help, but I am very grateful.
Finally, I have an amazing family. My wife Lorill, who is my partner and best friend, and my children have supported me and put up with my travels, late nights, and weekends for many years. I am grateful to them, and to all of you for this honor. Thank you.