# Charles T. Haan

Charles Thomas (Tom) Haan (1941–2024) was an American agricultural engineer and hydrologist, a Sarkeys Distinguished Professor and Regents Professor at Oklahoma State University (OSU), and a member of the National Academy of Engineering (NAE).<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup> He was known for applying statistical and stochastic methods to hydrology, the field of his textbook *Statistical Methods in Hydrology*.

| Fact | Detail |
|---|---|
| Born | 1941, Randolph County, Indiana<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup> |
| Education | B.S. and M.S. in Agricultural Engineering, Purdue University; Ph.D., Iowa State University, 1967<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup> |
| OSU posts | Department Head, Biosystems and Agricultural Engineering, 1978–1984; later Regents Professor and Sarkeys Distinguished Professor; retired 2001<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup> |
| Specialty | Statistical and stochastic hydrology; watershed modeling<sup>[2](https://catalog.okstate.edu/engineering-architecture-technology/biosystems-agricultural-engineering/)</sup> |
| Textbook | *Statistical Methods in Hydrology*, 1st ed. 1977, 2nd ed. 2002<sup>[3](https://find.mtsu.edu/vufind/Record/mig00004281372)</sup> |
| Honours | NAE member; ASABE Fellow; Sarkeys Distinguished Professor<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup> |
| Died | 2024<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup> |

## Education and career

Haan graduated from Jefferson High School in [Jefferson](https://www.edgepedia.org/jefferson), Indiana, in 1959 and earned B.S. and M.S. degrees in Agricultural Engineering at [Purdue University](https://www.edgepedia.org/purdue-university). In 1964 he moved to [Ames, Iowa](https://www.edgepedia.org/ames-iowa), completing his Ph.D. in Agricultural Engineering at Iowa State University in 1967.<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup>

He served on the faculty of the [University of Kentucky](https://www.edgepedia.org/university-of-kentucky) until 1978, when he moved to [Stillwater, Oklahoma](https://www.edgepedia.org/stillwater-oklahoma), as head of the Department of Biosystems and Agricultural Engineering at Oklahoma State University, a post he held through 1984. He remained at OSU as a Sarkeys Distinguished Professor and, by the time of the 2002 second edition of his textbook, a Regents Professor and Sarkeys Distinguished Professor, Emeritus. He retired from Oklahoma State in 2001.<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup>

## Statistical hydrology and watershed modeling

Statistical hydrology applies probability and statistics to water data: rainfall, runoff, floods, and pollutant loads are treated as random variables whose frequency, uncertainty, and trends can be estimated. Haan's textbook *Statistical Methods in Hydrology*, first published in 1977 with a second edition in 2002, presented these methods for hydrologic analysis.<sup>[4](https://www.amazon.com/Statistical-Methods-Hydrology-Charles-Thomas/dp/081381510X)</sup>

The graduate curriculum of the OSU department he led reflects this specialty. Its catalog describes BAE 5313 Watershed Modeling, a computer modeling course on the chemical and physical processes governing [nonpoint source pollution](https://www.edgepedia.org/nonpoint-source-pollution) (nitrogen, phosphorus, sediment) at the basin scale, and BAE 6313 Stochastic Methods in [Hydrology](https://www.edgepedia.org/hydrology), covering stochastic and statistical analyses of surface water and groundwater systems.<sup>[2](https://catalog.okstate.edu/engineering-architecture-technology/biosystems-agricultural-engineering/)</sup> The department itself is interdisciplinary, administered jointly by the Ferguson College of Agriculture and the College of Engineering, Architecture and Technology, with an ABET-accredited degree.<sup>[2](https://catalog.okstate.edu/engineering-architecture-technology/biosystems-agricultural-engineering/)</sup>

## Honours and recognition

Haan was a member of the National Academy of Engineering, an ASABE Fellow, and a Sarkeys Distinguished Professor at Oklahoma State.<sup>[1](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)</sup>

## References

1. [Charles Haan Obituary – Bryan, TX](https://www.dignitymemorial.com/obituaries/bryan-tx/charles-haan-12112878)
2. [Biosystems and Agricultural Engineering – Oklahoma State University Catalog](https://catalog.okstate.edu/engineering-architecture-technology/biosystems-agricultural-engineering/)
3. [Mig00004281372 (find.mtsu.edu)](https://find.mtsu.edu/vufind/Record/mig00004281372)
4. [081381510X (amazon.com)](https://www.amazon.com/Statistical-Methods-Hydrology-Charles-Thomas/dp/081381510X)

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*Topic: Encyclopedia › Technology and the built world › Engineers and computer scientists › Engineers and materials scientists › Researchers in civil, environmental, and water engineering; agriculture and food science › Water resources engineering and hydrology*

*Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026 · Edited: Sep 30, 2026; Oct 11, 2026; Oct 12, 2026 · Last review: Sep 30, 2026*

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