Department of Geography

• Watershed hydrology, especially in areas of complex terrain
• 3-D groundwater modeling
• GIS and remote sensing as tools for spatial data analysis
• Numerical methods to solve geologic and hydrogeologic problems
• Land-surface energy balance modeling
• Hydrologic implications of a changing climate
• Water infrastructure, water sustainability
• Soil moisture, vapor-intrusion studies

Dr. Letsinger is not currently recruiting new graduate students to supervise, but serves as a committee member on graduate student research projects.

Sally Letsinger is a hydrogeologist with over 30 years of experience in applying an interdisciplinary background and analytical skills to a wide range of natural-resource issues. She has served as principal investigator on many projects in  areas using coupled GIS and numerical or statistical modeling (both groundwater and surface water) to guide prioritization of best management practices; recharge-discharge area mapping; and determination of wetland hydrologic function for restoration or mitigation banking. Recent projects have involved natural hazard risk analysis applied to topics as diverse as aquifer sensitivity to contamination, sinkhole development, and fault-slip. The effect of the composition of source water distributed through drinking water distribution systems, water infrastructure, and water sustainability under climate change are new areas of inquiry.

• Letsinger, S.L., and Gustin, A.R., 2024. Regional water study: Water Demand and Availability in the Driftwood, Flatrock-Haw, and Upper East Fork White River Watersheds; Report to Indiana Finance Authority, Award 079396-00002B, 106 p. plus appendices http://dx.doi.org/10.13140/RG.2.2.21349.17126 (available at: https://www.in.gov/ifa/files/LetsingerGustin_I74CorridorWaterStudy_2024-02-14.pdf)
• Letsinger, S.L., Balberg, A., and Gustin, A.R., 2021, Implications to aquifer storage from shifts in timing of water-balance partitioning: report to Indiana Department of Environmental Management, Award #41486, 90 p. plus appendices. http://dx.doi.org/10.13140/RG.2.2.22549.70881
• Letsinger, S.L., and Branam, T., 2019, An assessment of the persistence of chloride in the pathway from source water to tap: A pilot study: report to Indiana Finance Authority, June 29, 2019, 55 p. http://dx.doi.org/10.13140/RG.2.2.26524.05769
• Indiana Finance Authority (authored by: Letsinger, S.L.), 2019, Indiana Lead Sampling Program for Public Schools, 32 p.
• Rupp, J.A., Letsinger, S.L., and Carlson, G., 2018, Fault angle control on potential seismic slip in the Illinois Basin region: Seismological Research Letters, doi: 10.1785/0220180153.
• Medina, C.R., Letsinger, S.L., and Olyphant, G.A., 2017, Hydrogeologic modeling of an area subjected to detailed geologic mapping in three dimensions: Do the details really matter? In, Kehew, A.E., and Curry, B. B., eds., Quaternary Glaciation of the Great Lakes Region: Process, Landforms, Sediments, and Chronology: Geological Society of America Special Paper 530, doi: 10.1130/2017.2530(11).
• Letsinger, S.L., 2017, Geological investigations of the distribution of arsenic in groundwater: report to Indiana Department of Environmental Management, Contract ARN A305-6-190, 132 p. http://dx.doi.org/10.13140/RG.2.2.25066.29123
• Naylor, S., Letsinger, S.L., Ficklin, D.L., Ellett, K.M., and Olyphant, G.A, 2016, A hydropedological approach to quantifying groundwater recharge in various glacial settings of the mid-continental U.S.A.: Hydrological Processes, v. 30, p. 1594-1608. doi: 10.1002/hyp.10718.
• Letsinger, S.L., 2015, Relationship of groundwater recharge rates to aquifer sensitivity to contamination in shallow aquifers in Indiana using multiple regression analysis: report to Indiana Department of Environmental Management, Contract ARN A305-2-52, 32 p. http://dx.doi.org/10.13140/RG.2.2.11644.51842
• Letsinger, S.L., 2015, Map of Indiana showing near-surface aquifer sensitivity: Indiana Geological Survey Miscellaneous Map MM-93.
• Letsinger, S.L., 2015, Map of Indiana showing near-surface aquifer recharge: Indiana Geological Survey Miscellaneous Map MM-92.
• Letsinger, S.L., 2015, Map showing sinkhole development risk in south-central Indiana and north-central Kentucky: Indiana Geological Survey Miscellaneous Map MM-91.
• Letsinger, S.L., and Olyphant, G.A., 2007, Distributed energy balance modeling of snow cover evolution and melt in rugged terrain: Tobacco Root Mountains, Montana, USA: Journal of Hydrology, v.336, no. 1-2, pp. 48-60. doi:10.1016/j.jhydrol.2006.12.012.