Famous groundwater hydrology modeler Thomas (Tom) A. Prickett began his career at the Illinois State Water Survey (ISWS) and continued being involved with the survey his entire life. Prickett originally enrolled at the University of Illinois in 1953 to pursue a degree in electrical engineering. However, he felt he was not serious about his studies and decided to join the Marine Corp Reserves. In September 1958 he returned to the U. of I. to earn a Bachelor of Science degree in general engineering. He graduated in 1960 and was hired by the ISWS after graduation. Despite starting out with no experience in hydrology, he quickly learned about groundwater physics and field investigations.
His first project at the ISWS was to advance electric analog groundwater modeling with co-investigator William (Bill) C. Walton (Wehrmann, 2008). His background in electrical engineering was helpful for this project and together they wrote, “Hydrogeologic Electric Analog Computers” (Walton & Prickett, 1963). This groundbreaking paper included instructions for constructing and using analog models and uniquely presented the theory behind how electricity is an analog for groundwater flow (Wehrmann, 2008). Later, Prickett published another paper on electric analog groundwater modeling with instructions on how to add pumped well attributes (Prickett, 1967).
Prickett’s work has been translated and published internationally. In 1965 he published the first graph depicting an estimate of “the time at which the effects of delayed gravity drainage cease to influence drawdown and the first graph of the relationship of the ‘delay index’ to the character of the materials through which gravity drainage takes place” (Wehrmann, 2008). This influential paper focused on the transient flow theory. Zhang Hongren later translated this paper into Chinese because of its impact in the field (Wehrmann, 2008).
On another ISWS project, Prickett developed the Prickett-Lonnquist Aquifer Simulation Model (PLASM) with C.G. Lonnquist in 1971 (History, n.d.). PLASM “was one of the first readily available numerical groundwater flow models.” This model was a precursor to the USGS MODFLOW model and was the first introduction to groundwater modeling for hundreds of people in the groundwater industry. The code was printed in Bulletin 55, which was sought after for years after its publication. When mainframe computers and computer cards were replaced by personal computers, Prickett quickly changed the code and formed the foundation for future consulting applications (Wehrmann, 2008).
During the mid-1960s, Prickett consulted on projects while working at the ISWS. Through this work he was involved in projects all over the world, including an analog model design in Saskatchewan, Canada and aquifer analysis in El Salvador. Eventually, when Prickett left the ISWS in 1977, he joined the Camp Dresser McKee (CDM) and opened an office in Champaign. His more famous clientele from this period included the U.S. Navy and Army, Exxon, and Mobil Oil. He left CDM in 1981 to open Thomas A. Prickett and Associates, his own consulting business.
That same year, Prickett published his solute transport code, which became known as The Random Walk Model (Wehrmann, 2008). The model was useful to see how different particles would flow through groundwater (Groundwater Research Community Remembers Prickett, 2007). He was able to publish this code with the help of the ISWS staff.
As his fame and consulting business grew, Prickett was called upon to appear in court, often to defend the various models he created. He had two appearances before the International Joint Commission because one of his models showed that boron from power plant ash lagoons in Canada were moving toward the U.S. border. Another famous court appearance was before the U.S. Supreme Court during the Kansas v. Colorado, No. 105 Original. He appeared on behalf of the State of Kansas after Kansas charged Colorado with violating the Arkansas River Compact when Colorado drilled irrigation wells. Kansas argued these wells were taking water from the river, which violated the Arkansas River Compact that the two states agreed to in 1949 (KANSAS v. COLORADO, n.d.).
Prickett remained an important part of the ISWS community after his departure and would often visit the ISWS. H. Allen Wehrmann remembered Prickett stopping by and chatting about how the ISWS was doing, Prickett's health, and the latest Fighting Illini teams. Prickett also assisted with the effort to preserve several electric analog models from the 1960s. These models were originally gifted to the International Groundwater Modeling Center at the Colorado School of Mines, but they no longer had space for them. After receiving permission from Eileen Poeter, the IGWMC director, Prickett and ISWS staff went to the Colorado School of Mines and retrieved the models. Once back with the models, Prickett cleaned them, created their labels, and supervised their assembly for display in a hallway in Building 4 at the ISWS. He passed away shortly afterward. The electric analog models are currently on display in the hallway and conference room in ISWS Building 4 on Griffith Drive in Champaign and serve as a reminder to staff of the role the ISWS played in the pioneering work related to groundwater flow modeling.
Groundwater Research Community Remembers Prickett. (2007). Water Matters Magazine. https://www.swfwmd.state.fl.us/blog/watermatters-magazine/26/groundwater-research-community-remembers-prickett
History. (n.d.). Illinois State Water Survey. Retrieved March 2, 2022, from https://www.isws.illinois.edu/about/history
KANSAS v. COLORADO. (n.d.). LII/Legal Information Institute. Retrieved August 2, 2022, from https://www.law.cornell.edu/supremecourt/text/105ORIG
Prickett, T. A. (1967). Designing Pumped Well Characteristics into Electric Analog Models. Groundwater, 5(4), 38–46. https://doi.org/10.1111/j.1745-6584.1967.tb01625.x
Walton, W. C., & Prickett, T. A. (1963). Hydrogeologic Electric Analog Computers. Journal of the Hydraulics Division, 89(6), 67–91. https://doi.org/10.1061/JYCEAJ.0000969
Wehrmann, H. A. (2008). Thomas A. “Tom” Prickett (1935 to 2007)—Ground Water Modeling Pioneer. Groundwater, 46(6), 910–914. https://doi.org/10.1111/j.1745-6584.2008.00492.x