Aaron Mittelstet

Watershed Hydrologist, Associate Professor, Robert B. Daugherty Water For Food Institute Fellow

Academic Degrees

  • Ph.D., Biosystems and Agricultural Engineering, Oklahoma State University, 2015
  • M.S., Environmental Science, Oklahoma State University, 2009
  • B.S., Zoology, Oklahoma State University, 2000


  • PhD, FE

Current Graduate Students

Moaz Ishag, MS Biological Systems Engineering, Expected Graduation: Summer 2024; Research Topic: Quantifying Current and Future Water Needs for Irrigation in northern Sudan.

Osman Adam, MS Biological Systems Engineering, Expected Graduation: Fall 2024; Research Topic: Enhancing Water Sustainability in North Africa: Literature Review and Synthesis of Current Knowledge Gaps in Sudan

Muili Lawal, MS Biological Systems Engineering, Expected Graduation: Fall 2024; Research Topic: Vadoze Zone Nitrate Accumulation in Relation to Manuare Application, Fertilizer Management, and Groundwater Nitrate Concentrations

Prajwol Thapa, MS Biological Systems Engineering, Expected Graduation: Fall 2024; Research Topic: Field Data Informed Models to Identify Type and Placement of Best Management Practices to Reduced Nitrate in the Bazile Creek Watershed

Amit Topno, PhD Biological Systems Engineering, Expected Graduation: Spring 2027; Research Topic: Field Data Informed Models to Identify Type and Placement of Best Management Practices to Reduced Nitrate in the Bazile Creek Watershed

Jean Niwenshuti, PhD School of Natural Resources, Expected Graduation: Fall, 2026; Research Topic: Evaluting Irrigation and Soil Erosion Practices to Improve Irrigation Efficiency and Reduce Soil Erosion in Rwanda

Past Graduate Students

Matthew Chaffee, MS Biolgical Systems Engineering, Graduation: December 2023; Thesis Title: Enhancing Urban Water Quality through Biological-Chemical Treatment: Aquatic Macroinvertebrate Community and Temporal Chlorophyll-a Response. Currently employed with the Army Corps of Engineers.

Yaser Kishawi, PhD Biological Systems Engineering, Graduation: May 2022; Dissertation Title: Impacts of Eastern Redcedar Encroachment on Water Resources in teh Nebraska Sandhills Under Different Climatic Scenarios: Currently working for Nebraska Department of Natural Resources.

Caner Zeyrek (co-advised with Dr. Troy Gilmore), PhD School of Natural Resources,  Graduation: May 2022; Dissertation Title: Modeling Groundwater Flow and Transit Time Distributioins in the Nebraska Sandhills. Currently employed with Mott Macdonald as a hydrogeologist.

Nawaraj Shrestha, PhD School of Natural Resources, Graduation: July 2021; Dissertation Title: Understanding lake dynamics and redcedar encroachment in the Nebraska Sandhills: A remote sensing and modeling perspective. Currently employed by the University of Nebraska-Lincoln in the School of Natural Resources.

Galen Richards, M.S. School of Natural Resources, Graduation date: July 2020; Thesis Title: Survey of Groundwater Transit Times and Nitrate Delivery to Bazile Creek. Currently PhD student at the University of Idaho in the Department of Soil & Water Systems.

Jessie Johnson, M.S. Biological Systems Engineering,  Graduation date: May 2020; Thesis Title: Application of an ultrasonic sensor to monitor soil erosion and depostion and implications for improving resilience, policy and outreach in riparian ecosystems. Currently employed with NRCS in Holdridge, NE.

Jess Satiroff, M.S. Environmental Engineering, Biological Systems Engineering, Graduation date: July 2020; Thesis Title: Pesticide occurence and persistence entering recreational lakes residing in watersheds of various land uses.

Matthew Russell, M.S. School of Natural Resources, Graduation date: May 2020; Thesis Title: Impact of streambank stabilization on sediment depostion and erosion in central Nebraska. Currently PhD student in Biological Systems Engineering at University of Kentucky, Lexington, KY.

Olufemi Abimbola, PhD Biological Systems Engineering, Graduation: December 2019; Dissertation Title: Modeling streambed vertical hydraulic conductivity, water quality pollutants, and best management practices using machine learning and the soil and water assessment tool. Currently employed by Syngenta in Data Science & Predictive Analytics.

Naisargi Dave, M.S. Environmental Engineering, Biological Systems Engineering, Graduation date: July 2018; Thesis Title: Evaluation of Effectiveness of Streambank Stabilization Practices and Flood Impact on Cedar River, Nebraska


  • 60% Research
  • 40% Teaching

Curriculum Vitae (CV):

Mittelstet_Curriculum Vitae.doc

Areas of Research and Professional Interest

  • Watershed Modeling
  • Surface/Ground Water Interaction
  • Water Quality
  • Streambank Erosion

Research Profiles:

Courses Taught

About Aaron Mittelstet

Aaron Mittelstet joined the Biological Systems Engineering Department in 2016 and was promoted to Associate Professor in 2022. He teaches courses within BSE and advises undergraduate, graduate, and Ph.D. students. Mittelstet is also a courtesy Associate Professor within the School of Natural Resources and serves as a fellow for the Robert B. Daugherty Water for Food Institute. Mittelstet has published several publications over the years and earned numerous grants for his research. His interests are in the areas of watershed modeling, surface/groundwater interaction, water quality, and streambank erosion.  Mittelstet advises the UNL Fountain Wars Design Team. Fountain Wars is a hands-on competition in which a team of up to six students design a fountain to complete challenges using the necessary PVC pipes, couplers, fittings, valves, nozzles, and pumps. He earned his Ph.D. in Biosystems and Agricultural Engineering; his M.S. in Environmental Science; and his B.S. in Zoology all from Oklahoma State University.

Honors and Awards

  • 2020 ASABE Superior Paper award
  • 2018 UNL College of Engineering Recognition for Highly Impactful Research
  • M.S. student Naisargi Dave won 1st Place at the 2017 Water for Food Conference Poster Contest
  • 2nd Place, Student Poster Contest, 23rd Annual Oklahoma Clean Lakes and Watersheds Association Conference, Stillwater, OK, 2014.
  • Outstanding Manuscript Reviewer Award, ASABE, 2013.
  • 3rd Place, Student Poster Contest,  OWRRI Oklahoma Water Research Symposium, Midwest City, OK, 2013.
  • 2nd place, Environmental Science Graduate Paper Presentation, OWRRI Oklahoma State Water Research Symposium, Stillwater, OK, 2011.
  • Jimmie Pigg Environmental Policy Research Assistantship, 2009.


1. "Using a coupled surface water/groundwater model informed by groundwater age, geophysics, and vadose zone coring to identify type and placement of management practices to reduce legacy groundwater nitrate concentrations" (January 2023 – December 2025)
Sponsor: USGS 104g
PI: A.R. Mittelstet (40%), T.E. Gilmore (30%), D. Snow (15%), E. Haacker (15%)
Sponsor Amount: $249,977

2. "Vadose zone nitrate accumulation Lower Loup Natural Resources District Area 30, Relation to manure application, fertilizer management and groundwater nitrate concentrations" (August 2022 – July 2024)
Sponsor: Lower Loup Natural Resource District
PI: D. Snow (34%) Co-PI: A.R. Mittelstet (33%), T. Gilmore (33%)
Sponsor Amount: $67,506

3. "A biological and chemical approach to restoring eutrophic ponds in Nebraska" (September 2022 – August 2023)
Sponsor: USGS 104b Program
PI: A.R. Mittelstet (60%); Co-PI: S. Comfort (40%)
Sponsor Amount: $25,000

4. "Application of Remote Sensing and Hydrological Modeling to Reduce Highway Flooding in the Nebraska Sandhills" (July 2021-December 2022)
Sponsor: Nebraska Department of Transportation
PI: A.R. Mittelstet (65%); Co-PI: T. Gilmore (35%)
Sponsor Amount: $144,166

5. "Surface Water Nutrient Removal in Eutrophic Ponds Using Floating Treatment Wetlands in Nebraska" (Apr. 2021-Mar. 2024)
Sponsor: Nebraska Environmental Trust
PI: T. Messer (34%); Co-PI: A.R. Mittelstet (33%); S. Comfort (33%)
Sponsor Amount: $111,797

6. "Plan for Region Ephemeral Gully Erosion" (January 2020 to December 2020).
Sponsor: USDA-NRCS
PI: T. Franti (55%) Co-PI: A.R. Mittelstet (15%), W. Woldt (15%), P. Jasa (15%)
Sponsor Amount: $66,486

7. "Evaluation of Watershed-scale Groundwater Transit Time Distributions from Field Sampling and Numerical Modeling" (May 2018 to May 2021)
Sponsor: National Science Foundation
PI: T. Gilmore (50%) Co-PI: A.R. Mittelstet (40%), V. Zlotnik (10%)
Sponsor Amount: $880,944; UNL: $387,030

8. "Survey of Groundwater Transit Times and Nitrate Delivery to Bazile Creek" (June 2018 – May 2020)
Sponsor: Department of Environmental Quality
PI: T.G. Gilmore (50%); Co-PI: A.R. Mittelstet (40%); T.L. Messer (10%)
Sponsor Amount: $30,000

9. "Quantifying Cost-Efficiency of Streambank Stabilization Practices on Cedar River" (Apr. 2018-Mar. 2020)
Sponsor: Nebraska Environmental Trust
PI: A.R. Mittelstet (92%); Co-PI: Lower Loup RC&D (8%)
Sponsor Amount: $92,849

10. "Quantifying the Effects of Eastern Red Cedar Encroachment on Recharge in the Nebraska Sandhills" (Jan. 2018-Dec. 2021)
Sponsor: Water Sustainability Fund
PI: A.R. Mittelstet (60%); Co-PI: C. Neale (20%); Craig Allen (10%); Dirac Twidwell (10%)
Sponsor Amount: $144,716

11. "Pesticide Exposure in Recreational Lakes" (Mar. 2018-Feb. 2019)
Sponsor: USGS 104b Program
PI: T.L. Messer (50%); Co-PI: A.R. Mittelstet (25%); Co-PI: D. Snow (25%)
Sponsor Amount: $24,967

12. "Pollutant Load Reduction Due to BMP Implementation in the Big Sandy Creek Watershed" (July 2017 - June 30, 2018)
Sponsor: Natural Resources Conservation Service
PI: A. Mittelstet (100%)
Sponsor Amount: $25,031

13. "Spatial Variability of Streambed Conductivity across Multiple Stream Orders" (June 2017 – May. 2018)
Sponsor: USGS 104b Program
PI: A.R. Mittelstet (65%); Co-PI: T.E. Gilmore (35%)
Sponsor Amount: $19,992

Selected Publications

  1. Jensen, C.R., D.P. Genereux, T.E. Gilmore, D.K. Solomon, A.R. Mittelstet, C.E. Humphrey, M.R. MacNamara, C. Zeyrek, V. Zlotnik. 2022. Estimating groundwater age from SF6 in stream water: An application of the reach mass-balance approach to groundwater mean transit time in the Nebraska Sand Hills. Hydrogeology. Accepted 
  2. Russell, M.1, Mittelstet, A.R., Messer, T.L., and Korus, J. 2021. Quantification of erosional and depositional processes near implemented streambank stabilization practices. Ecological Engineering 170: 106357https://doi.org/10.1016/j.ecoleng.2021.106357
  1. Russell, M.V.1, A.R. Mittelstet, R.M. Joeckel, J. T. Korus, C. Castro-Bolinaga and T.L. Messer. 2021. Impact of bank stabilization structures on upstream and downstream bank mobilization at Cedar River, Nebraska.  Transactions of the ASABE 64(5): 1555-1567. 
  2. Shrestha, N.2, A.R. Mittelstet, V.A. Zlotnik and T.E. Gilmore. 2021. Correlation between drought and lake area of groundwater-fed lake areas in the Western Lake Region: the Nebraska Sandhills. Journal of Hydrology Regional Studies 36: 100877. https://doi.org/10.1016/j.ejrh.2021.100877 
  1. Shrestha, N.1, A.R. Mittelstet, A. Young, T.E. Gilmore, D. Gosselin, Y.Qi and C. Zeyrek. Groundwater level assessment and prediction in the Nebraska Sand Hills using LIDAR-derived lake water level. Journal of Hydrologyhttps://doi.org/10.1016/j.jhydrol.2021.126582  
  2. Abimbola, O.2, G. E. Meyer, A.R. Mittelstet, D.R. Rudnick and T.E. Franz. 2021. Knowledge-guided machine learning for improving daily soil temperature prediction across the United States. Vadose Zone Journalhttps://doi.org/10.1002/vzj2.20151 
  3. Knox, J. and A.R. Mittelstet. 2021. Application of an ultrasonic sensor to monitor soil erosion and deposition. Transactions of the ASABE 64(3): 963-974. ISSN 2151-0032 https://doi.org/10.13031/trans.14236 
  4. Satiroff, J.1, T.L. Messer, A.R. Mittelstet and D. Snow. 2021. Pesticide exposure in recreational lakes: Nebraska case study. Environmental Pollution 273:116399. https://doi.org/10.1016/j.envpol.2020.116399 
  5. Wells, M.J., T.E. Gilmore, N. Nelson, A.R. Mittelstet and J.K. Bohlke. 2021. Determination of vadose and saturated zone lag times using long-term groundwater nitrate monitoring and statistical machine learning. Hydrology and Earth System Sciences 25(2): 811-829. https://doi.org/10.5194/hess-25-811-2021 
  6. Abimobla, O.P.2, A.R. Mittelstet, T.L. Messer, E.D. Berry and A. van Griensven.  2021. Modeling and prioritizing interventions using pollution hotspots for reducing nutrients, Atrazine and Escherichia coli concentration in a watershed. Sustainability 13(1): 103. https://doi.org/10.3390/su13010103