Andrew J Long


Andy Long has more than 25 years experience assessing groundwater flow and transport through numerical modeling, analyzing ambient tracers, and geophysical methods.


Ph.D., Geological Engineering (hydrology), 2000, South Dakota School of Mines and Technology (SDSMT)

M.S., Geological Engineering (hydrology), 1995, SDSMT

B.S., Geological Engineering, 1993, SDSMT

Selected Appointments

  • 2015-present: Hydrologist and Groundwater Specialist, USGS Washington Water Science Center. In addition to continuing my research activities, I advise the Science Center on technical issues, including interpretive studies, data collection, and archival. I assist the Center in building and guiding the overall groundwater studies and data program.
  • 2014-2017: National Research Council committee to evaluate the implementation of the Edwards Aquifer Habitat Conservation Plan (
  • 2009-2015: Research Hydrologist, USGS South Dakota Water Science Center. Primary activities included the development of innovative methods to better understand, quantify, and test hypotheses related to groundwater flow and transport in karst aquifers. Groundwater age dating, lumped-parameter models, aquifer classification, hydrochemical evaluation, heat transport, and groundwater recharge were some areas of my research.
  • 2005-present: Adjunct Assistant Professor, South Dakota School of Mines and Technology. I served on the graduate advisory committees for five M.S. students and three Ph.D. students. Seven of these students were employed by the USGS and did their research primarily under my direction as part of their USGS work. I gave numerous guest lectures at SDSMT.
  • 1999-2009: Hydrologist, U.S. Geological Survey (USGS), South Dakota Water Science Center. I Conducted numerical modeling of groundwater flow and solute transport, dye tracing experiments in karst aquifers, development of new research models.

Full list of publications is at ORCID.

Selected publications are below.