Vijay K. Gupta

2008 Robert E. Horton Medal Winner

Vijay K. Gupta was awarded the 2008 Robert E. Horton Medal at the AGU Fall Meeting Honors Ceremony, held 17 December 2008 in San Francisco, Calif. The medal is for “outstanding contributions to hydrology.”


The AGU Robert E. Horton Medal represents the pinnacle of achievement in the field of scientific hydrology. Today, one of hydrology’s visionaries, Vijay Gupta, receives this unique honor for his fundamental contributions to the evolution of hydrology as a geophysical science. I am proud to deliver this citation.

After completing his Ph.D. in 1973, Vijay embarked on a long odyssey of scientific discovery through the whole of the hydrological landscape. From the outset, he recognized the fundamental importance of scale. It became a pervasive theme in all his work, which has ranged uniquely from the molecular to the planetary scale. Throughout, Vijay has eschewed the traditional, safer, specialist route with assured incremental progress for more integrative and risky directions that can redefine the field through unforeseen but enduring advances.

Vijay’s early work with mathematician Rabi Bhattacharya and soil physicist and Horton medalist Gary Sposito led him to develop an understanding of multiscale dispersion of solutes in aquifers based in molecular dynamics. It provided an important foundation for subsequent work in the field. The mathematical elegance of this body of work became a hallmark of all of his research. His parallel work with mathematician Ed Waymire on space-time rainfall variability on multiple scales has impacted the field for more than two decades. Vijay’s recently published paper on understanding the physical basis of statistical clustering and scale invariance in rainfall lays a foundation for modern hydrometeorology.

His major excursion into geomorphology led him to derive generalized Horton laws for the rescaled full probability distributions of drainage areas and stream lengths for a new class of random self-similar networks. This groundbreaking work was to lay the foundation for his research on a multiscale geophysical theory of floods in river basins. It was largely inspired by a question posed by Dave Dawdy: “How can we understand the geophysical basis of regional annual flood statistics widely used in engineering?” Building on his research results for idealized basins, Vijay has established the multidisciplinary, multiscale Hydro-Kansas experimentation program in the Whitewater Basin, Kansas, to test some new hypotheses.

The hypothesis of self-regulation underlying the Gaia theory of Lovelock and Margulies fascinated Vijay immensely. In a recent paper, he showed the strength of negative feedbacks from the hydrological cycle in regulating the planetary climate for a warming Sun.

As an encapsulating tribute to Vijay’s research, the following quote from Horton’s biography seems particularly apposite: “…his continual thinking across disciplinary lines and his continual interplay between engineering practice and scientific curiosity…”

Over the past two decades, Vijay has unselfishly mobilized or led major community research initiatives. Most notable among these is the “Water, Earth, Biota (WEB)” visionary report, an implementation plan for Opportunities in the Hydrologic Sciences, which spawned the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI). He also inspired the launch of the International Association of Hydrological Sciences decade on Prediction in Ungauged Basins (PUB).

Vijay is always ready to share ideas, philosophy, and time with those who seek his advice and leadership, and many have. His calm but assured manner and clear analytical thinking empower others. All will applaud the award of the Horton Medal to this inspirational scientist and engineer.

—EDNA O’CONNELL, University of Newcastle upon Tyne, UK


Thank you, Enda, for your generous citation. I acknowledge all who supported my nomination, AGU, and the medal committee, for this honor.

The Robert E. Horton Medal is the most visible milestone in my uncharted academic journey that began exactly 40 years ago. Cooperation from numerous colleagues and students made it possible. I enthusiastically share this medal with all of them.

Joining a unique statistical hydrology program under Vujica M. Yevjevich at Colorado State University in 1968 was a great beginning. My early association with Dave Dawdy blossomed into a lifelong collaboration and friendship. My move to the University of Arizona in 1971 was exciting and challenging. The untimely passing away of my advisor, Chester Kisiel, served as a catalyst to explore “risky directions” rather than follow a “safer, specialist route.” For example, I was drawn to Rabi Bhattacharya and Gary Sposito for their originality and brilliance. Therefore, I moved away from my dissertation topic of rainfall and began a serious collaboration in subsurface hydrology with them. I acknowledge Sol Reznick for his foresight to encourage and support our collaboration. Three foundational ideas unified our research: (1) the link between physical processes, statistical variability, and geometry, (2) asymptotics and limit theorems, and (3) scale invariance and scale dependence. They became a road map to all my joint research.

My collaboration with Ed Waymire at Ole Miss flourished because of his dedication and clarity for mathematical applications in sciences. The nurturing environment was pivotal that administrators like Karl Brenkert, Allie Smith, and Pete Wagner created. We greatly appreciated Steve Mock of the Army Research Office for funding our unconventional ideas. My rude awakening to the “real world” occurred after joining the University of Colorado in 1989. But I was very fortunate to expand my research opportunities while facing ever growing challenges, locally.

I acknowledge all of my national and international collaborators from hydrology, engineering, physics, geophysics, statistics, geomorphology, fluid mechanics, meteorology, and ecology, who became an integral part of a highly interdisciplinary multiscale research agenda. Many outstanding students, from Oscar Mesa to Ricardo Mantilla, representing different disciplines became the backbone of my research.

In 1984, the sudden elimination of the National Science Foundation’s [NSF] hydrology and hydraulics grants program from the Engineering Directorate was a major setback, which fueled my persistent community service efforts. I acknowledge the team effort from Pete Eagleson (Massachusetts Institute of Technology) for his leadership, Marshall Moss (U.S. Geological Survey), Ignacio Rodriguez-Iturbe (Princeton University), and others who brought about a new hydrology grants program in the Geoscience Directorate. I especially recognize Doug James (NSF), and numerous colleagues, whose wisdom and hard work contributed to our collective efforts on “Water, Earth, Biota” to guide this program.

My next frontier is to develop a unified theory that views “life” as the basic link between “geophysiology” and “consciousness.” As water is essential to life, the global water cycle is the key to understanding environmental self-regulation. I grasped the profound connection between consciousness and life after years of guidance from a contemporary Indian philosopher, Tatvagyani Vethathiri. I have no words to give him due reverence.

I am privileged to inherit the legacy of my father, a hydraulics research engineer, and my love for mathematics from my mother, which made this journey possible.

My gratitude to my wife, Indira, is unmatched for being who she is.

—VIJAY K. GUPTA, University of Colorado, Boulder