Below you will find publications written by our staff, affiliated faculty, and graduate students. Topics of the publications range from groundwater sustainability studies to Memphis aquifer studies. Studies are linked if they are open access. Otherwise, If you would like access to any of these, please reach out to us or the authors of the publication.
By Daniel Larsen, Brian Waldron, Scott Schoefernacker, Haley Gallo, John Koban, and Elizabeth Bradshaw. 2016.
Fourteen years of environmental tracer data sampling for 3H, He isotopes, noble gases, and SF6 screened from production wells were analyzed and used to determine the vulnerability and sustainability of the Memphis aquifer. Usage of these tracer systems showed wells are at greater risk than previously thought and require further study.
By Randall Gentry, Teh-Lung Ku, Shangde Luo, Vincent Todd, Daniel Larsen, and John McCarthy. 2005.
A known aquitard window (or clay layer breach) located in the Sheahan wellfield in Shelby County, Tennessee was assessed for uranium- and thorium- series radioisotopes. Findings from these wells were then compared to other geochemical properties found in this system. The tracers used were determined to be useful in establishing a new conceptual model for aquifer behavior in and around recharge sites.
By Daniel Larsen, Scott Schoefernacker, and Brian Waldron. 2017.
In 2015, the University of Memphis Center for Applied Earth Science and Engineering Research (CAESER) conducted sampling of several wells in Shelby County to trace contaminations. They found the wells in Collierville showed contamination from nearby surface waters. Because of this, it was recommended monitoring to be continued.
By Stephanie Ivey, Randall Gentry, Dan Larsen, and Jerry Anderson. 2008.
An inverse age-distribution model employing tritium and helium-3, was successfully used to determine the location of a leakage source near the Sheahan Wellfield in Memphis, Tennessee. Thus, this technique was deduced to be effective in locating further breaches of unconfined aquifers.
By Daniel Larsen, Randall W. Gentry, and D.K. Solomon. 2002.
The usage of 3 H and 3 H/3 He groundwater dating, and geochemical modeling was found to be essential to assess the mixing fractions and the timing of modern recharge in the Memphis aquifer. In this study, the water chemistry and 3 H activity showed the shallow Na-SO4-Cl rich water being influenced by recharge of modern water vertically through the upper Claiborne confining unit. Also, modern recharge that infiltrated 15-20 years ago, was determined to be present in five shallow production wells by using 3 H/3 He dates. Results from a geochemical reaction modeling using NETPATH code was deemed to correlate well with the found 3 H/3 He dates, which proved these methods are paramount to determining proportions of modern recharge leaking into semi-confined aquifers.
By Stephanie S. Ivey, Randall W. Gentry, Dan Larsen, and Jerry Anderson. 2008.
In this study researchers utilized age-distribution modeling together with environmental tracers (tritium/helium-3), geochemical, and other hydrogeologic data to determine if a certain methodology could efficiently identify recharge areas of a wellhead where infiltration of modern water exists. It was found the exponential-piston flow model (EPM), used in conjunction with environmental tracer data and geochemical information, was effective at locating the source of recharge to an unconfined aquifer. Using this method, researchers were able to determine the linear extent of the recharge area, distance from the well to the recharge source, the amount of tritium free water, and the recharge variability.
By Daniel Larsen and Brian Waldron. 2014.
The data collected over a span of 14 years indicated a presence of modern water in many of the municipal wells located in Shelby County, and found the mixing percentages in these production wells. Based on these results, it was concluded the Memphis aquifer is vulnerable to contamination, and an increase in funding was recommended.
By Brian Waldron, James Harris, Daniel Larsen, and A. Pell. 2009.
An aquitard breach was mapped using seismic reflection near Shelby County Landfill in Memphis, Tennessee. From past research using boreholes, the confining clay layer, or aquitard, was found to have a natural breach. However, the extent of the breach was not known. Using seismic reflection to map the subsurface, researchers determined the extent and the distribution of the breach that is a conduit for landfill leachate to move into the Memphis aquifer.
By Chris H. Cramer, Roy B. Van Arsdale, Mahesh S. Dhar, Daniel Pyrne, and Justin Paul. 2014.
A Memphis urban seismic-hazard map was completed for the area of Memphis and southern Shelby County in 2004. This map included the probabilistic and scenario of seismic and liquefaction hazards in the set area. This map was then updated in 2014, due to a new geologic model for Shelby County and included Vs measurements.
By Brian Waldron and Daniel Larsen. 2014.
The State of Mississippi filed a lawsuit against the City of Memphis and Memphis Light, Gas, and Water (MLGW) in 2005, alleging groundwater owned by State of Mississippi was unrightfully channeled into Tennessee by City of Memphis and MLGW. The State of Mississippi based their lawsuit on a pre-development potentiometric surface map, which was found to be ill-suited to support Mississippi’s claim, as a control point used was not taken from a well screened within the Memphis aquifer, and water levels used for the other controls were post-pre-development. The results of this study reinforced the necessity of forming an accurate water level map based on pre-development conditions and the importance of keeping records of ground water levels.
Daniel Larsen, John Bursi, Brian Waldron, Scott Schoefernacker, and James Eason. 2019.
To determine rates and recharge paths of the Memphis aquifer, meteorological and hydrologic measurements, geochemistry, and applied and environmental tracer data, was analyzed. It was found that recharge is mostly sourced from preferential pathways, such as stream seepage and lateral recharge. Based on these results, land development in loess-covered areas could compromise the integrity of the Memphis aquifer.
By Randall W. Gentry, Teh-Lung Ku, Shangde Luo, Vincent Todd, Daniel Larsen, and John McCarthy. 2005.
The Sheahan wellfield in Shelby County, Tennessee is affected by an aquitard window that is known to be in the vicinity of the wellfield. Here a study was conducted to develop a new conceptual model for aquifer behavior near recharge sites where the local groundwater pumping is affecting hydraulic pathways. To develop the model, hydrogeochemical tracers (U, Th, Ra, and Rn) and groundwater tracers, tritium and helium-3, were used. Using these tracers, they determined one of the wells had the youngest fraction of water and had similar behavior of Th and U as ground waters at the window source.
By Lensyl Urbano, Brian Waldron, Dan Larsen, and Heather Shook. 2005.
A theoretical, numerical model was developed by researchers to assess the movement between groundwater flow systems and streams that intersect where unconfined aquifers turn confined. The development of this model was important to understanding groundwater-surfacewater interactions as most previous theoretical models have been only two-dimensional cross section. Using the results of the model, it was found in the case where stream reaches overlie transition zones, the geometry and properties of the confining unit are of similar importance as the aquifers own characteristics. These results were also compared to stream-discharge measurements gathered from a location where the Loosahatchie River crosses a transition zone in the upper Mississippi Embayment, which provided some support for the model results.
By Farhad Jazaei, Brian Waldron, Scott Schoefernacker, and Daniel Larsen. 2018.
This study used three analyses to create a MODFLOW-based numerical model to provide information and explanations for future investigations into groundwater problems. By using these three methods, five areas with possible breaches were identified. Past studies showed similar findings, lending to the credibility of using numerical models to solve hydrogeological problems.
Ivey, S., Olson, B., and Reeb, T. (2021). Visualizing Equality in the New Mobility Workforce.In. E. Ozdenerol (ed.),Gender Inequalities: GIS Approaches to Gender Analysis.CRC Press. ISBN 9780367184735.
Yu, H., Zhou, Y., Ivey, S., and Lang, Y. (2019) Large-Scale Multibaseline Phase Unwrapping: Interferogram Segmentation based on Multibaseline Envelope-Sparsity Theorem. IEEE Transactions on Geoscience and Remote Sensing, 57(11), pp. 9308-9322. 10.1109/TGRS.2019.2926096
Sarram, G. and Ivey, S. (2018). Investigating Customer Satisfaction Patterns in a Community Livability Context: An Efficiency-Oriented Decision-Making Approach, Proceedings of the 2018 International Conference on Transportation and Development, Pittsburgh, PA, July 2018.