Announcement of the Hantush-Deju Center

- by John L. Wilson, Sept. 23, 2022

I was asked to speak about the past, present, and future of hydrology research at New Mexico Tech. But first I want to thank Dr. Deju, President Wells, and Dr. Stephens for their roles in helping to establish this new center.

In 1973 I was a Ph.D. student at MIT walking down the hall outside my lab, when I encountered my mentor and advisor, Lynn Gelhar. He stopped to talk with me. “I’m leaving MIT,” he said, “and moving to a new position.”

I was briefly taken aback. “Where?”

He replied, “Socorro.”

My quizzical look prompted him to add “Mahdi Hantush.”

I made the connection. Gelhar was moving to New Mexico Tech where much of the seminal work on the mathematical modeling of well hydraulics had been done by Hantush and his colleagues, including Charles E. Jacob.

Well hydraulics, or well testing, uses a perturbation to a groundwater well, by initiating pumping or by shutting off production, to promote an aquifer-pressure response. The perturbation and response are observed and, fitting the data with one or more of Hantush’s clever mathematical models, the groundwater aquifer conditions and properties can be diagnosed. In other words, Hantush used mathematics to develop diagnostic tools for hydrogeologists.

But not only for hydrogeologists. This week, I grabbed a book off my office shelf concerning well testing for petroleum-reservoir engineering. Published by Exxon in the 1990s, it is by a Russian author (Tatiana Streltsova). It contains 23 citations to Hantush’s work, and another three independent citations to Jacob, and three more to Stavros Papadopoulos, a former Hantush student. The well hydraulics research at NM Tech had global reach and is still widely used today.

Hantush and Jacob were gone by the early 1970s. Gelhar and his new Tech colleagues became the next generation of Tech hydrologists. Gelhar brought an interest in the effects of the small-scale spatial variation of aquifer properties on groundwater flow and the associated movement of dissolved chemicals, like groundwater contaminant. If you take the time to observe a highway outcrop sediment or rock you’ll see this kind of spatial variation. It’s ubiquitous, although it ranges in magnitude and how quickly it varies over distance. You can’t see the variation from the land surface, it’s underground, but you can describe it statistically and characterize flow as a stochastic or random process. Borrowing from his background in fluid mechanics Gelhar devised a mathematical approach to solve this problem, creating the field of stochastic groundwater hydrology, another foundational contribution with global impact. In the mid-1990s many new groundwater Ph.D. theses in the U.S. and Europe were based on Gellar’s foundation.

Toward the end of his tenure at Tech, Gelhar brought in two key young colleagues - Dan Stephens and Fred Phillips. I arrived a couple of years later. It was at this time that the Tech hydrology program began to expand its focus, in both topics and the range of research methods. More and more people joined us, eventually embracing a full range of hydrologic-science topics. Here are three (of the many possible) examples from over the last 30 years.

The vadose zone is that portion of the subsurface between the land surface and the water table. We asked questions like:

• “What controls the movement of watering associated dissolved chemicals through the vadose zone to arrive later at the water table as groundwater recharge?” Dan Stephens did extensive field investigations in the 1980s and 90s on this question, culminating in THE “Vadose Zone Hydrology” textbook, and memorialized recently in his election to the National Academy of Engineering.
• “How does the vadose zone interact with plants and evapotranspiration at the surface?” Phillips’ group did field work that showed that in the dry bottoms of the southwestern U.S. basins none of the water escapes the demands of evapotranspiration and recharge in mountains where there is recharge; later followed by the Hydrology Program’s development of similar models for the entire state of New Mexico as part of a statewide water balance study.
• “How can all of this be observed in the field?” Jan Hendrickx marshaled new satellite remote sensing technology to non-invasively estimate water content, evapotranspiration, and groundwater recharge across the landscape.

My second example recognizes that humans are not good housekeepers. We leak or spill organic liquids like gasoline from underground storage tanks and chlorinated solvents from industrial facilities and dry cleaners. What happens when those organic liquids reach the vadose zone, or the water-saturated aquifer below, as they have done in cities, towns, and military bases around the world? In the 1990s my group did extensive laboratory experiments on these questions. The research was the subject of a 50-university lecture tour sponsored by the National Groundwater Association. The bottom line is that it is better to regulate and avoid these situations, than try to clean them up, as has been well illustrated by the current remediation activities at Kirtland AFB in Albuquerque and Red Hill at Pearl Harbor in Hawaii.

My last example takes us to the ocean. In the shallow oceans of the planet, offshore of islands and continents, there are often freshwater resources trapped by geology and explained by lower sea-levels in the geologic past. Mark Person has been developing models of these off-shore freshwater processes for different areas around the planet, starting with models of the continental shelf off of Boston and New York. This is a future drinking water supply and, in areas with offshore oil production, the shallow offshore freshwater can be used to enhance offshore oil production.

Historically, Tech’s hydrology program has emphasized collaboration across the group, department, and institute, as well as collaboration with other institutions. For example:

• The offshore freshwater program includes work with Woods Hole Oceanographic Institution, LANL (Los Alamos National Laboratory), Columbia, and other institutions. I was also involved.
• Allan Gutjahr of the Mathematics Department was an important collaborator on Gellar’s stochastic hydrology research.
• Over twenty years ago we initiated a Department of Energy sponsored program the geologic sequestration of CO2 (CCS) with the PRRC and other outside institutions. Alex Fine Hart continues that collaboration today.
• Dan Cadol leads research on arroyo and dry-stream sediment erosion, transport, and deposition, with implications for the sediment loading of the Rio Grande and other semi-arid rivers around the planet. It’s a collaboration with USBR, the Israelis, and the department’s geophysicists.
• Phillips and I are working on a study of the paleohydrology and tectonics of the Great Basin (SE California and southern Nevada) over the last 12 million years, in an effort to understand how aquatic organisms evolved over time in that area. Its genomics, groundwater, and geology, G3, in a collaborative effort of five universities and the USGS.

The new Hantush-Deju Center for Hydrologic Innovation can initially leverage and expand on some of these current research and collaborative efforts.

But I understand that the center will mainly look to establish new research initiatives, and on integrating collaborative efforts across campus and with other institutions to address these new initiatives.

In simple terms, the center should “create a culture that is open to new ideas, brings people together, excites them (and possible research sponsors), and drives them towards new hydrologic science and its application.” These goals were recently articulated to me by Dr. Rinehart.

What are some of these future opportunities that are aimed at both basic understanding and its application to solving problems? After talking to some of the center’s likely faculty I have two suggestions, both focus on technology rather than science questions.

Artificial Intelligence

AI is, among other things, the ability of a computer to do tasks that are usually done by humans because they require human intelligence or judgment.

Machine Learning (ML) programming is a particular AI approach that can perform tasks without necessarily being programed to do so. We’ve used ML with hydrologic models for over 30 years. My job-interview lecture at NMT, in the mid 1980s, presented the development and application of an extended Kalman Filter ML algorithm for the evolution and improvement of groundwater models.

But, outside of ML, few of the other aspects of AI have found a home in hydrologic science, although they have found applications in related water engineering, e.g., water supply and irrigation infrastructure operations and monitoring.

It appears that one likely focus of the center will be on enhancing ML technology, and in developing other aspects of AI, to improve the science of hydrology and its applications.

A second possible focus is

Geodesy and Geophysics

The center could focus on leveraging new tools from geodesy and geophysics to non-invasively measure and understand surface and subsurface conditions, including vadose-zone and groundwater flow and storage.

For example, Cadol’s arroyo-based sediment-yield studies include innovative ground-mounted seismic and micro gravity instruments to indirectly measure streamflow, stream-sediment transport, and groundwater recharge.

At larger spatial scales, in another example, is InSAR (Interferometer Synthetic Aperture Radar). This is a technique for mapping ground deformation using radar images of the Earth’s surface that are collected from orbiting satellites. The images can be used to map changes in land subsidence, groundwater storage, and groundwater levels, and have been demonstrated in groundwater basins. I would like to see them applied, together with gravity measurements, to non-invasively probe mountains where we have few wells and very poor understanding of their subsurface plumbing.

These are just two possibilities.

The Center provides an opportunity to bring people together to catalyze new research ideas, helping society to address the many critical water problems that we face in the presence of a limited resource, human development, and climate change.

---

50 Years of Hydrology at the College on the Rio Grande 

- by Enrique R. Vivoni, Oct. 2006

While the exact date is a topic of debate, this much we know. Between 1954 and 1956, during the leadership of President E.J. Workman, New Mexico Tech established a presence in the burgeoning field of hydrology. At this time, few, if any, hydrologic science programs existed in the United States with hydrology courses typically taught in geology or civil engineering. Fifty years later, hydrology is an established geoscience discipline with a growing number of university programs throughout the world. Over this period, New Mexico Tech has served an important role in the development of hydrology as a science and as an integrated course of study at the graduate level.

In celebration of the 50th anniversary of the Hydrology Program, this article discusses a few of the historical highlights as well as our current teaching and research efforts. Much of the program history has been documented by John Wilson in The Porous Media newsletter (Vol. 1, Issue 1, 1991 and Vol. 2, Issue 1, 1993). As will be discussed in the following, the 50-year history of program follows, in many ways, the development of hydrology as a geoscience that is well-integrated with the Earth Science community. By attracting top talent, the program has been resilient in light of changes in scientific focus, societal needs and competition from other programs.

According to several accounts, E.J. Workman convinced Mahdi Hantush, an Iraqi hydrologist educated in the United States, to commence a teaching and research program in groundwater hydrology at Tech. This new program was complementary to New Mexico Tech’s efforts in geology, geophysics and atmospheric physics. The program started with modest funds from the Geophysical Research Center and a handful of courses taught in the Department of Groundwater Hydrology. During the early years, the focus was primarily on transient groundwater flow problems with both a theoretical and applied emphasis. G. Emlen Hall recounts that the first funded hydrology project at New Mexico Tech was in support of groundwater resources of the Roswell area.

During the period 1956-1970, the Hydrology Program grew with respect to the number of graduating students, faculty, and scientific productivity. For example, 15 M.S. and Ph.D. degrees were granted in groundwater hydrology during this period. Following Hantush’s frequent visits to the Middle East in the mid-1960s, leadership in the Hydrology Program was transferred to C.E. Jacob in 1965. As Hantush’s advisor, Jacob was already a well-established leader in groundwater hydrology. As a result of their efforts during this period, New Mexico Tech became nationally recognized as a place for the study of well hydraulics. Today, most groundwater textbooks include their seminal discoveries made in Socorro along with their numerous students.

After a brief transition following Jacob’s passing in 1970, the Hydrology Program, now in the Department of Geosciences, was led by Lynn Gelhar, a groundwater hydrologist from MIT. Gelhar reinvigorated the program during the period 1973-1982, with cutting-edge research being conducted by a growing group of students and faculty. Along with Allan Gutjahr, Gelhar created a nationally-recognized program in stochastic groundwater hydrology. Following national trends, the program also expanded its focus into numerical methods, hydrogeochemistry and vadose zone processes and resulted in international recognition for students and faculty alike. For example, John Wilson (1996) and Fred Phillips (2001) received the O.E. Meinzer Award, following in the footsteps of Hantush and Gelhar. In addition, the program has expanded into other areas including cave and karst hydrology, remote sensing and ecohydrology. Alongside this has been an effort to create an integrated graduate program in hydrologic science with a wide appeal to both M.S. and Ph.D. students. Today, graduates from the program are highly sought out for jobs in consulting, government agencies and academia.

As we mark the 50th anniversary of the Hydrology Program, it is important to reflect upon this historical background. This success story in the College on the Rio Grande is the product of significant efforts (i.e., blood, sweat, and tears) by many students, staff, administrators and faculty. Yet the road ahead is as exciting and challenging as the path that has been traveled. For example, an effort is underway to redesign our graduate curriculum to educate the next generation of hydrologic scientists. We are also designing a new B.S. degree that will offer a specialization in hydrology. Our tech innovations are accompanied by a strong commitment toward cutting edge research. We continue to seek new discoveries that impact hydrologic science and move us toward a deeper understanding of the natural world.