Stream Loss Contributions to a Municipal Water Supply Aquifer in Memphis, Tennessee

Larsen, Daniel; Morat, Jason; Waldron, Brian; Ivey, Stephanie; Anderson, Jerry L.

doi:10.2113/gseegeosci.19.3.265

Cited by 16 publications

(53 citation statements)

References 30 publications

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“…Although the EPMP is based on the conceptual model, in practice the model value is based on fitting the results to the specified model with the least error. The primary issue is that the width of the window, x, is poorly constrained, even in situations where the distance to the window, x*, is constrained by other data (e.g., Sheahan well field, Larsen et al ; ; Ivey et al ). However, the actual sensitivity of the EPM results on the EPMP is minimal in some cases.…”

Section: Discussionmentioning

confidence: 99%

“…Hydrogeologic windows are intervals in the upper Claiborne confining unit that are thin due to erosion (e.g., Bradley ) or comprise predominantly sand facies rather than silt and clay (e.g., Larsen et al ), such that water may be exchanged between the Shallow and Memphis aquifers. More recently, 3 H/ 3 He and geochemical data from production wells have shown a clear association of modern water in the Memphis aquifer with proximity to hydrogeologic windows (Larsen et al ; Gentry et al ; Ivey et al ; Koban et al ; Larsen et al ). Several of these studies using tracers and geochemical mixing models showed that as much as 75% of the water produced from some production wells is modern water, likely from a nearby surface water source (Larsen et al ; Koban et al ; Larsen et al ; Gallo ).…”

Section: Hydrogeologic Backgroundmentioning

confidence: 99%

“…Memphis aquifer with proximity to hydrogeologic windows (Larsen et al 2003;Gentry et al 2005;Ivey et al 2008;Koban et al 2011;Larsen et al 2013). Several of these studies using tracers and geochemical mixing models showed that as much as 75% of the water produced from some production wells is modern water, likely from a nearby surface water source (Larsen et al 2003;Koban et al 2011;Larsen et al 2013;Gallo 2015).…”

Section: Journal Of Contemporary Water Research and Education Ucowrmentioning

confidence: 99%

See 2 more Smart Citations

Application of Environmental Tracers in the Memphis Aquifer and Implication for Sustainability of Groundwater Resources in the Memphis Metropolitan Area, Tennessee

Larsen

Waldron

Schoefernacker

et al. 2016

Contemporary Water Research

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Fourteen years of results from environmental tracer sampling for 3H, He isotopes, noble gases, and SF6 in production wells screened in the Memphis aquifer in Memphis, Tennessee, are presented and used to determine the age and mass proportion of modern water (<60 years old) pumped from this regionally important public supply aquifer. The results indicate persistent presence of modern water in water pumped from one or more production wells in most of the well fields sampled. The percentage of modern water is quantified by three methods: tritium‐loading history, inverse geochemical modeling, and lumped parameter modeling. The mixing percentages and ages determined from each technique are generally in agreement, but also emphasize the unique information provided by each tracer and associated modeling approaches. The implications of the tracer data for sustainability and vulnerability are also considered, especially in regard to potential water quality threats to the water supply in the Memphis, Tennessee, metropolitan area.

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Section: Discussionmentioning

confidence: 99%

Section: Hydrogeologic Backgroundmentioning

confidence: 99%

Section: Journal Of Contemporary Water Research and Education Ucowrmentioning

confidence: 99%

See 1 more Smart Citation

Application of Environmental Tracers in the Memphis Aquifer and Implication for Sustainability of Groundwater Resources in the Memphis Metropolitan Area, Tennessee

Larsen

Waldron

Schoefernacker

et al. 2016

Contemporary Water Research

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“…So far, two different approaches have been employed to answer this question. The first approach is the "geochemical investigation" [7][8][9][10][11][12][13] where groundwater samples are analyzed to identify geochemical signatures that are attributed to surface water within the groundwater. Within the Memphis area, age-dating of groundwater by using tritium-helium-3 and sulfur hexafluoride support geochemical data, and reflects the influence of modern water (<50 years) in the Memphis aquifer.…”

Section: Introductionmentioning

confidence: 99%

“…Within the Memphis area, age-dating of groundwater by using tritium-helium-3 and sulfur hexafluoride support geochemical data, and reflects the influence of modern water (<50 years) in the Memphis aquifer. Subsequent studies have shown that modern water contributes up to 40% of groundwater withdrawn from production wells-in one case, production water contains as much as 75% modern water [9][10][11]. The second approach is the "geological investigation", in which techniques, such as surveying stratigraphic thickness and water table elevation, electrical resistivity surveys, shear-wave seismic reflection, and other geophysical analyses are used to identify gaps in impermeable layers [5,[14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Application of Numerical Tools to Investigate a Leaky Aquitard beneath Urban Well Fields

Jazaei

Waldron

Schoefernacker

et al. 2018

Water

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Memphis aquifer is the primary drinking water source in Shelby County (Tennessee, USA), and it supplies industrial, commercial, and residential water. Memphis aquifer is separated from the Shallow aquifer by a clayey layer known as the Upper Claiborne confining unit (UCCU). All of the production wells in the Memphis area are screened in the Memphis aquifer, or even deeper in the Fort Pillow aquifer. Traditionally, it was assumed that the UCCU could fully protect the Memphis aquifer from the contaminated Shallow aquifer groundwater. However, recent studies show that at some locations, the UCCU is thin or absent, which possibly leads to the contribution of Shallow aquifer to the Memphis aquifer. Accurately locating the breaches demands expensive and difficult geological or geochemical investigations, especially within an urban area. Hence, a pre-field investigation to identify the locations where the presence of breaches is likely can significantly reduce the cost of field investigations and improve their results. In this study, to identify the locations where the presence of breaches in the UCCU is likely, we develop a reliable MODFLOW-based numerical model, and use three different analyses: (1) pilot-point calibration (PPC), (2) velocity and flow budget (VFB), and (3) particle tracking (PT), to post-process the developed groundwater model results. These pre-field numerical investigations provide relevant and defensible explanations for groundwater flow anomalies in an aquifer system for informed decision-making and future field investigations. In this study, we identify five specific zones within the broad study area which are reasonable candidates for the future field investigations. Finally, we test the results of each analysis against other evidence for breaches, to demonstrate that the results of the numerical analyses are reliable and supported by previous studies.

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Comprehensive, Multi‐Scale Evaluation of Field Methods for Assessing Stream–Aquifer Interactions Along Channelised Lowland Streams

Ledesma,

Villalpando‐Vizcaino,

Larsen

et al. 2024

Hydrological Processes

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Stream–aquifer interactions (SAIs) play a critical role in effective groundwater management, yet their complex dynamics remain poorly understood in channelized lowland perennial streams. This study presents a multi‐scale, multi‐technique investigation of SAIs along two long‐stream reaches in Tennessee, United States. The goal is to define a suitable methodology for characterising SAIs in this specific hydrological setting, serving as a starting point for developing a more standardised and replicable approach. The methodology includes an initial evaluation of various field techniques, followed by extensive surveys using potentiomanometers, electromagnetic induction (EMI), vertical temperature profilers (VTPs) and complementary methods such as seepage meters, bank tests and well‐data analyses. Results reveal distinct hydrogeomorphic behaviours across and along the streams, challenging the SAI‐homogeneity notions typically assumed in groundwater models. Nonconnah Creek exhibited streambed colmation and negligible hydraulic gradients, resulting in disconnection from the aquifer during low flows, except for a 300‐m losing reach with high downward gradients. In contrast, the Loosahatchie River displayed relatively homogeneous streambed properties and small, upward hydraulic gradients, suggesting uniform SAIs along the surveyed reaches. EMI proved highly effective for mapping streambed sediments quickly, while potentiomanometers accurately measured small head differences critical for understanding SAI dynamics. VTPs were less practical due to the extended data‐collection times required and their vulnerability to flooding. This study emphasises the importance of multi‐scale investigations using diverse techniques to accurately characterise SAIs in lowland streams, highlighting the confounding influences of geological formations, anthropogenic alterations and depositional processes on groundwater–surface water interactions. The findings contribute to refining local water balances, informing groundwater management strategies and underscoring the need for incorporating local‐scale field data into regional groundwater models. The proposed methodology serves as a foundation for developing a standardised approach for characterising SAIs in lowland channelized perennial streams, adaptable for similar stream systems worldwide.

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Stream Loss Contributions to a Municipal Water Supply Aquifer in Memphis, Tennessee

Cited by 16 publications

References 30 publications

Application of Environmental Tracers in the Memphis Aquifer and Implication for Sustainability of Groundwater Resources in the Memphis Metropolitan Area, Tennessee

Application of Environmental Tracers in the Memphis Aquifer and Implication for Sustainability of Groundwater Resources in the Memphis Metropolitan Area, Tennessee

Application of Numerical Tools to Investigate a Leaky Aquitard beneath Urban Well Fields

Comprehensive, Multi‐Scale Evaluation of Field Methods for Assessing Stream–Aquifer Interactions Along Channelised Lowland Streams

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