Ignacio Rodriguez-Iturbe

1998 Robert E. Horton Medal Winner

Texas A&M University, College Station

Ignacio Rodriguez-Iturbe was awarded the Robert E. Horton Medal at the AGU Spring Meeting Honors Ceremony, which was held on May 27, 1998, in Boston, Massachusetts. The Robert E. Horton Medal recognizes outstanding contributions to the geophysical aspects of hydrology.


“The Horton Medal is the highest honor bestowed upon hydrologists. Indeed the list of past winners is very impressive. In the words of my colleague, Pete Eagleson, ‘today we add the foremost surface water hydrologist.’ I fully concur.

“Ignacio Rodriguez-lturbe has been a major player in, if not originator of, some of the most significant hydrologic breakthroughs in the last 30 years. Allow me to sketch an extraordinary time line.

“In late 1960s and early 1970s, he clarified the debate on the occurrence and persistence of hydrologic extremes, commonly known as the Hurst phenomenon. He formulated one of the first self-similar models to simulate extreme behavior.

“In early 1970s, he framed the whole issue of monitoring network design as one of sampling of random fields. For the first time the art became a science.

“In mid-1970s, he introduced Bayesian approaches to estimate parameters of streamflow simulating models and to select models of extremes. The profession suddenly had a consistent way to use regional information to predict extreme hydrologic behavior in regions with limited data.

“In the late 1970s and early 1980s, he re-energized the field of fluvial geomorphology with a fresh look at basin organization and its relation to basin response. He developed the Geomorphologic Instantaneous Unit Hydrograph (GIUH), the most successful attempt to quantify the discharge of a basin as a function of basin geometry and rainfall.

“He has led the revolution in fluvial geomorphology from the late 1980s to the present by developing a whole new theory of river basin organization and evolution. The new theory has shown that organization of the basin and resulting landscape patterns are not the result of randomness but process-driven phenomena that can be quantified in terms of well-defined principles.

“During the 1980s and 1990s, Ignacio also spearheaded the use of point processes and fields to represent precipitation in space and time. We now have virtual realities that facilitate forecasting and analysis in hydrometeorology.

“Since the late 1980s, he also showed the impact that simple nonlinearities in the land-atmosphere dynamics have on patterns of hydrologic variables, like soil moisture. Droughts, for example, may be enhanced by the complicated feedbacks between the land and the atmosphere.

“This record is sufficient for many careers. However, let me assure you, he is not finished! He is now immersed in biology, seeking new inspiration to solve problems in hydrology.

“Professor Donald Nielsen captured the essence of this scientist when he wrote: ‘To be in the same room with Ignacio is an inspirational experience. He brings the wisdom of the past, the direction of the present, and the uncharted, yet to be conceived, approaches of the future into full view. He challenges each of us to the depths of our understandings, and at the same time encourages risk, excitement, and scientific reward. I know of no other contemporary hydrologist who lives each day inspiring those inside and outside of hydrologic science more than does Ignacio.’

“That ebullience and contagious enthusiasm has propelled many of his students to very successful careers. I am proud to be one of them.

“Merely to know Ignacio’s science is to miss his most important quality, his humanity. Ignacio is a man of impeccable honesty, of deeply rooted principles, and of uncompromising devotion and loyalty. All this packaged in a hyperactive body and mind, full of humor and zest for life. He is the friend, the confidant, and the inseparable companion of his wife, Mercedes. He is the loving beacon to his five children: Oscar, Ignacio, Olympia, Juan, and Luis. To his friends, he is the reliable counselor who is always present when needed and is also the bearer of good cheer. I look forward to our weekly telephone conversations.

“President Solomon, ladies and gentlemen, it is an honor to introduce my mentor, friend, and brother. As a colleague put it, the ‘Paganini of Hydrology’–the winner of the Horton Medal–Ignacio Rodriguez-lturbe.”

—RAFAEL L. BRAS, Massachusetts Institute of Technology, Cambridge, Mass.


“President Solomon, ladies and gentlemen:

“Thank you, Rafael, for your most generous words. It is like a dream for me to receive the Horton Medal and even more so to receive it in Boston, a city so special for all my family. I have been extremely lucky to be a hydrologist during a time that has seen the field transformed from an appendix of hydraulics, -full of empirical formulas and driven by the requests of engineering practice, to a science of its own, motivated by the desire to understand how nature works that, as a consequence, brings the capability to solve. The fact that hydrology was ready to undergo a dramatic transformation was made clear to me by my undergraduate advisor in Venezuela, Jan Laszewsky. This was reinforced when I joined the hydrology program at Colorado State University, where hydrology was pursued and argued at every moment of the day. It was a marvelous time and the right place to be, with people like Jose Mejia, David Dawdy, Vijay Gupta, and Carl Nordin under the leadership of Vujica Yevjevich.

“My first paper submitted to AGU was sent in 1968 to Water Resources Research from Universidad del Zulia, handwritten with a letter explaining that to have it typed in English would take a long time and certainly would not improve its appearance! The editor was Walter Langbein, the first Horton medalist and a giant of the field. He read the manuscript and answered me in a handwritten letter that the paper would be reviewed, and if accepted, he would take care of the typing. I will always be grateful for this kind and generous answer to a very young and unknown hydrologist trying to do research under difficult circumstances. In early 1970, I received an invitation from Peter Eagleson to join the faculty at the Massachusetts Institute of Technology. It was the beginning of many personal and professional friendships that will last a lifetime, regardless of where we have been or where we will ever be.

“Throughout my academic life, I have been blessed with wonderful students that became dear friends and admired colleagues. Three of them who shared an office at MIT during the early 1970s are here tonight with their wives: Rafael Bras, department head at MIT, Juan Valdes, department head at the University of Arizona, and Eric Wood, former department chairman at Princeton. Indeed, I was lucky with the students that came my way! To all of them, I can only say thanks for graciously putting up with a peculiar advisor who would telephone late at night to talk about research. It was exciting! We got involved in all kinds of research problems and would continuously discuss what we perceived as the key challenges of the field. I was extremely fortunate during those years at MIT to have two exceptional academicians, Donald Harleman and Peter Eagleson as mentors, both personally and professionally. Our families will always be very close and I owe them more than I can express with words.

“In Venezuela, Universidad Simon Bolivar was a wonderful place to work with friends like Jose Cordova, Marcelo Gonzalez, Luis Castro, and Luis Pericchi, who are still very dear to me. From there, and through the generosity of many friends from all over the world, I was able to pursue a variety of topics that had been on my mind for a long time. With Andrea Rinaldo, of the University of Padova, I have had many especially exciting years of research and friendship, and I thank him for sharing with me his enthusiasm and creativity. Dara Entekhabi of MIT has also been a wonderful research partner, although he keeps remembering that I once told him he was ‘an ocean of useless information.’

“Rafael Bras was a spectacular student and a wonderful research partner from the very first day he walked into my office. Most importantly, he has always been a very special and dear friend. When we left MIT to go back to Venezuela, I assured Pete Eagleson I would not be missed. I said this with all sincerity. Rafael had decided to return from Puerto Rico to join the faculty, and I had no doubts whatsoever that he would quickly become a world leader in the field. Throughout the years, we have collaborated in many projects and, as time goes by, I feel more and more proud of his many accomplishments.

“Pete Eagleson, former president of AGU and the 1988 Horton medalist, has been my mentor, a most admired colleague, and true family, both in the good times and in the tough times. His work has been an inspiration for all of us since the 1960s, and we continuously share the excitement of research as well as the ups and downs of life. His friendship and trust acquire a deeper meaning as the years pass.

“I am forever thankful to AGU, which has been a most important institution in all my scientific endeavors regardless of where in the world I was living. Since 1993, Texas A&M University has provided a supportive environment for all of my activities, and I am especially grateful to Bud Peterson, our Associate Dean of Engineering.

“Finally, I want to thank my family. I always tell my students that to do good research it is necessary to be able to dream. If I have any capacity to dream I owe it to my father, who until the end of his life, after being blind for years, would repeat that to see far and to see well one needs the eyes of the heart. The eyes of my heart have always been on Mercedes and our children, from whom I have learned, day after day, the meaning of love and generosity. As we say in Spanish, amor con amor se paga.’ Thirty-five years ago, my senior thesis in Maracaibo started with the words, to Mercedes with love and dreams.’ Tonight this wonderful medal is for her, with the same love and the same dreams of 35 years ago.”

—IGNACIO RODRIGUEZ-ITURBE, Texas A&M University, College Station