Shlomo P. Neuman

2003 Robert E. Horton Medal Winner

University of Arizona, Tucson

Shlomo P. Neuman was awarded the Horton Medal at the AGU Fall Meeting Honors Ceremony, which was held on 10 December 2003, in San Francisco, California. The medal honors “outstanding contributions to hydrology.”


“I am proud to introduce Shlomo P. Neuman, Regents’ Professor of Hydrology and Water Resources at the University of Arizona, as the 2003 AGU Horton Medalist. Shlomo’s contributions to subsurface hydrology helped define the science and its practice in the last 40 years. He is uniquely deserving of the Horton Medal.

“Shlomo’s research centers around theoretical, computational, and field analyses of fluid flow and solute transport in porous and fractured geologic media, reflecting a philosophy according to which hydrology requires the application of rigorous thinking to complex scientific and engineering problems. He conducts his research within a rigorous theoretical framework nevertheless applicable to real-world problems. His approach has led to major advances in our understanding of flow and transport processes under a broad range of field conditions, within a wide range of hydrogeologic environments, that are of both scientific significance and practical relevance; and in our ability to describe and generalize such processes mathematically, simulate and analyze them computationally, and measure and observe them in the field.

“Shlomo’s unique approach stems from his undergraduate education in geology and his graduate education in engineering. His M.S. work at UC Berkeley led to an elegant solution for flow through aquitards and the Neuman-Witherspoon ratio method to determine their hydraulic properties. His doctoral work resulted in a hydrodynamic theory of multiaquifer systems verified through a month-long pumping test spanning five formations under Oxnard, California. His early work on finite elements helped launch the era of computer flow simulations and explore the terra incognita of flow in the vadose zone. The Neuman method of analyzing flow to wells in unconfined aquifers has become the standard of the profession. Shlomo and his students and collaborators have made seminal contributions to hydrogeologic simulation, inverse theory, fractured rock hydrology, stochastic subsurface flow and transport theory, and hydrogeologic scaling. He pioneered the concept of hydraulic tomography and, with his students, used pneumatic tests to acquire the first fully three-dimensional tomographic images of permeability and porosity in the subsurface.

“Shlomo is an outstanding teacher and educator, many of whose students have become leaders in their fields. Thanks to Shlomo and his students, the University of Arizona Ph.D. program in hydrogeology consistently ranks best in the nation.

“I would be remiss not to comment on Shlomo’s remarkable personal history. Born in Czechoslovakia at the outbreak of World War II, Shlomo was interned by the Nazis only to discover later that his father and the vast majority of his extended family had perished in the Holocaust. He and the remnants of his family sought haven in Israel, where Shlomo acquired his undergraduate degree. He met his lovely wife, Yael, as a graduate student at U.C. Berkeley and, following a 4-year sojourn in Israel, his family settled in Tucson, where Shlomo continues to teach and churn out new ideas.

“For his outstanding contributions to hydrologic science, education, and practice I am proud to present the most highly deserving recipient of the 2003 Horton Medal, Shlomo P. Neuman.”

—SOROOSH SOROOSHIAN, University of California, Irvine


“Thank you, Soroosh, for your generous introduction. I am thrilled and humbled to be a recipient of this prestigious medal.

“My interest in hydrogeology was sparked by pioneering Israeli water projects of the 1960s. A warm letter of acceptance from a future Horton Medalist, Paul Witherspoon, enabled me to pursue an M.S. degree in geological engineering at U.C. Berkeley. There I was greeted by a future Macelwane Medalist, Al Freeze. What better induction into the field could one hope for? What good fortune would soon guide me to cross paths with my future wife and life companion, Yael? It is she who deserves the credit for my decision to pursue doctoral studies and a lifetime career of academic pursuit. Her unfailing support and understanding have earned her a full share of the honor bestowed on me today.

“With Paul Witherspoon I learned to appreciate the power of mathematics and computation in addressing fundamental and real-world hydrogeologic problems. The late Eshel Bresler and colleagues at the Agricultural Research Center in Israel helped kindle my interest in soil physics and the emerging field of vadose zone hydrology. Reinder Feddes of Wageningen Agricultural University helped open my eyes to the role played in hydrology by plants. Ghislain de Marsily and colleagues at the Paris School of Mines helped ignite my fascination with geostatistics and inverse problems. The opportunity to join a unique department fully dedicated to hydrology and water resources, aided by delay in an eventual offer of tenure from the Weizmann Institute of Science in Israel, led me to the University of Arizona. There I enjoyed early years of collaborations with the late Sid Yakowitz and Gene Simpson, and more recent years with Pete Wierenga, on a host of fascinating theoretical and experimental field projects championed in part by U.S. NRC project managers John Randall, Tom Nicholson, and Ralph Cady. My greatest reward came from close interaction with many unbelievably brilliant and wonderful young people who have helped produce much of the science recognized here today. The honor is theirs as much as mine. Since my younger collaborators are too numerous to name, the least I can do is tell them: Thank you for the privilege of having worked with you; I greatly appreciate the intellectual challenge and sheer pleasure of continuing to conduct joint research with some of you; I cherish your friendship and am immensely proud of our joint and your individual accomplishments. I am especially thrilled that one of you, Jesus Carrera, has been named 2004 Henry Darcy Medalist by the European Geophysical Society’s Hydrological Sciences Section.

“In the last several decades, major advances have been made in our understanding of hydrologic phenomena and our ability to interpret some of them within a self-consistent theoretical framework. A major remaining challenge is to extend and unify this phenomenological and theoretical understanding across the field so as to combine our somewhat disjoint subdisciplines into a more fully integrated and rigorous hydrologic science. I am personally most excited about steps already taken toward such integration in the areas of hydrologic simulation, uncertainty analysis, and scaling.

“I am deeply indebted to friends and colleagues who initiated and supported my nomination, and to members of the Horton Medal committee for their trust in the value of my contributions to hydrology. Thank you all for this wonderful honor.”

—SHLOMO P. NEUMAN, University of Arizona, Tucson