Jan M.H. Hendrickx is Professor of Hydrology in the Department of Earth and Environmental Science and a Research Hydrologist at the Geophysical Research Center of New Mexico Tech in Socorro, New Mexico. He was born 15 Sept. 1948 in Amerika, a small village in the southern Netherlands, and raised in Eindhoven. He lives in Los Lunas, New Mexico.
After graduating from the St. Vincentius Gymnasium Wernhoutsburg in Zundert, he received his B.S. and M.S. degrees in Civil Engineering and Irrigation from the Agricultural University Wageningen, The Netherlands, in 1975. He spent one year in Campina Grande, northeastern Brazil, as a volunteer for OXFAM and designed inexpensive trickle irrigation system with wind powered water supply as well as rainwater harvesting cisterns. After another year as an Irrigation and Drainage Engineer employed by Agrar und Hydrotechnik Gmbh in Tanzania and Germany, he became a Research Irrigation and Drainage Engineer for the Agricultural University Wageningen stationed at the Office du Niger in Niono, Mali, from 1979 to 1981. He conducted research on the water requirements of rice and sugarcane and established a soil physics laboratory. From 1981 to 1984 he was a Research Assistant at the Department of Agronomy and Horticulture of New Mexico State University. He conducted research on the spatial variability of soil moisture and the water requirements of trickle irrigated chile peppers under guidance of Dr. Peter Wierenga. He earned his Ph.D. degree in Soil Physics in 1984 and did postdoctoral work at the Department of Agricultural Engineering of Texas A&M University with Dr. John Nieber. In 1985, he became Head of the Department of Soil Physics and Hydrology of the Netherlands Soil Survey Institute in Wageningen, The Netherlands. With his colleague Dr. Louis Dekker and others he conducted research on the effects of unstable wetting on water flow and solute transport through field soils. Here he started to employ electromagnetic induction measurements for soil hydrology. From 1988 through 1990 he was stationed at the International Waterlogging and Salinity Research Institute in Lahore, Pakistan. With his team of Dutch and Pakistani researchers he conducted research on optimal management strategies of water quantity and quality in irrigated areas. He also established a soil physics laboratory.
In the fall of 1990, Dr. Hendrickx joined the faculty of the Hydrology Program of the Department of Earth and Environmental Science and the Geophysical Research Center at New Mexico Tech as, respectively, assistant professor and research hydrologist. He was promoted to associate professor in 1993 and to professor in 2001. He teaches graduate courses in Vadose Zone Hydrology, Groundwater Hydrology, Introduction to Remote Sensing, and Flow and Transport in Hydrologic Systems. He has been the advisor of one Ph.D. and 14 M.S. students.
Hendrickx’s research approach has been formed by his practical experience as an irrigation engineer in many parts of the world and by his doctoral training in the soil physics “school” of Kirkham-Nielsen-Wierenga. Hendrickx and his graduate students like to work in the field on relevant issues dealing with soil hydrology and soil physics. Laboratory measurements are taken if the field measurements do not suffice to test their hypotheses. Existing theoretical models are used or new ones developed to better understand or predict field phenomena. An example of this approach is his work on the effect of water repellent soils on pesticide movement that he and his colleagues at the Netherlands Soil Survey Institute conducted in the late eighties and early nineties. The research included field and laboratory work as well as a new modeling approach to model water flow through preferential flow paths caused by unstable wetting. The research clearly demonstrated that water repellent top soils lead to an increased vulnerability for ground water contamination by pesticides and provided guidelines to evaluate pesticide travel times.
The Hydrology Program and the Department of Mathematics at New Mexico Tech have had a strong synergistic relationship for fifty years. Hendrickx has taken full advantage of this unusual academic environment by vigorously pursuing several major challenges in soil physics. A stability analysis of the nonlinear partial differential equation that describes unsaturated water flow has been a research topic of much interest for soil physicists. Dr. Hendrickx and Dr. William D. Stone of the Department of Mathematics with their former graduate students Dr. T. (Mike) Yao and Dr. X.H. Du used their mathematical and experimental skills to develop a complete stability analysis of this equation. Previous analyses of unstable wetting fronts focused on soils with sharp wetting fronts such as coarse sands. The stability model developed by Hendrickx and his research team is unique in its capability to predict quantitatively unstable wetting and finger sizes in many different soils using readily available hydraulic soil properties for a wide range of precipitation rates.
Electromagnetic induction is a common technique for determination of the spatial distribution of soil salinity in agricultural fields and riparian areas. Since the early 1980s researchers have tried to develop a method to use this measurement technique also for the determination of vertical soil electrical conductivity profiles. Although some of these attempts were successful using site specific calibration curves, no generally applicable method was available. The problem is difficult since the inverse model is ill-defined. Hendrickx, Dr. Brian Borchers at the Department of Mathematics, and their graduate students used Tikhonov regularization to develop a solution for the prediction of vertical apparent electrical conductivity profiles without need for site specific calibration. This tool allows practitioners to obtain information of the distribution of soil salinity with depth without invasive soil sampling.
Landmines are “the most lethal form of soil contamination.” The detection of land mines is a challenging problem with high societal relevance that requires application of basic soil physics as well as a thorough understanding of the true nature of field soils. Hendrickx and Borchers with their graduate students have explored the physics of soil-sensor-mine systems to better understand the effect of the soil environment on land mine detection. They have published papers dealing with the effects of soil texture and soil water content as well as the spatial variability of these properties on the performance of ground penetrating radar and thermal sensors. Their work clearly identifies the limits and potentials of land mine sensors based on ground penetrating radar and thermal mine signatures.
Hendrickx has been very effective with the technology transfer of his research results on the use of electromagnetic induction in restoration of saline riparian soils. Many restoration projects have been and are undertaken in New Mexico, Texas, and Arizona to plant trees in small and large areas along the river. Unfortunately, many of these projects have failed in the past because soil salinity killed many trees. After Hendrickx�s research in the early 1990s clearly demonstrated that a low-cost pre-planting salinity survey using electromagnetic induction could boost tree survival rates from below 30% to well over 90%, he has honored many requests to conduct salinity surveys at potential reforestation sites. The requests were made by schools for tree planting projects with students, by environmental organizations, state organizations, Indian pueblos, and the federal government. His work has made an important impact on how soil restoration and reforestation is done in the Rio Grande Valley.
The physics of water flow and solute transport under unsaturated conditions is taught at very few universities in Latin America. Yet, there is a big need by professionals to learn about these processes. Hendrickx’s Vadose Zone Hydrology workshops in Spanish have brought soil physics for the first time to hundreds of professionals and students in Colombia, Mexico, Panama, and Venezuela. In his most recent workshops taught together with his wife, Ing. Graciela Rodríguez-Marín, seventy-five Colombian scientists, engineers, and students participated in the summer of 2000 at the National University of Colombia in Medellin and twenty-five in 2001 at the Technological University of Panama.
Dr. Hendrickx has authored or coauthored 50 refereed papers and 5 book chapters, has given 20 invited lectures for national and international audiences, and has presented more than 70 seminars. He has been a member of SSSA since 1982. He served as Associate Editor for the Soil Science Society of America Journal for Div. S-1. He is a Fellow of the Soil Science Society of America and a Fulbright Scholar.