Preliminary evaluation of the hydrogeology and groundwater quality of the Mississippi River Valley alluvial aquifer and Memphis aquifer at the Tennessee Valley Authority Allen Power Plants, Memphis, Shelby County, Tennessee
The hydrogeology, groundwater quality, and potential for hydraulic connection between the Mississippi River Valley alluvial aquifer and the Memphis aquifer in the area of the Tennessee Valley Authority (TVA) Allen Combined Cycle and Allen Fossil Plants in southwestern Memphis, Tennessee, were evaluated from September through December 2017. The study was designed as a preliminary assessment of the potential for leakage of groundwater from the Mississippi River Valley alluvial aquifer through the underlying upper Claiborne confining unit into the underlying Memphis aquifer at the plants. A short-term aquifer test of four of the five Memphis aquifer production wells installed at the Allen Combined Cycle Plant induced drawdown in water levels in the Mississippi River Valley alluvial aquifer, locally. The largest drawdown occurred in the eastern and southeastern parts of the TVA plants area, and generally was coincident with locations where stratigraphic data show increased thickness of and depth to the base of the alluvium and decreased thickness and inferred offset in the base of the confining unit relative to nearby locations. In contrast, stratigraphic data for most other locations at the site indicate shallower depths to the base of the alluvium and more consistent thickness of and depth to the base of the confining unit, which corresponds with areas where less drawdown was observed during the test. Water-quality results for samples from the production wells and from monitoring wells screened in the Mississippi River Valley alluvial aquifer indicate that groundwater with higher dissolved-solids concentrations and tritium from this shallow aquifer has mixed with water in the upper part of the Memphis aquifer at one of the production wells. Results of the study collectively confirm that the Mississippi River Valley alluvial and Memphis aquifers are hydraulically connected near the TVA plants area.
Citation Information
Publication Year | 2018 |
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Title | Preliminary evaluation of the hydrogeology and groundwater quality of the Mississippi River Valley alluvial aquifer and Memphis aquifer at the Tennessee Valley Authority Allen Power Plants, Memphis, Shelby County, Tennessee |
DOI | 10.3133/ofr20181097 |
Authors | John K. Carmichael, James A. Kingsbury, Daniel Larsen, Scott Schoefernacker |
Publication Type | Report |
Publication Subtype | USGS Numbered Series |
Series Title | Open-File Report |
Series Number | 2018-1097 |
Index ID | ofr20181097 |
Record Source | USGS Publications Warehouse |
USGS Organization | Lower Mississippi-Gulf Water Science Center |
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Water-level models used to estimate drawdown in 32 monitoring wells screened in the Mississippi River Valley Alluvial aquifer and 4 observation wells screened in the Memphis aquifer during an aquifer test at the Tennessee Valley Authority Allen power plan
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Water-level models used to estimate drawdown in 32 monitoring wells screened in the Mississippi River Valley Alluvial aquifer and 4 observation wells screened in the Memphis aquifer during an aquifer test at the Tennessee Valley Authority Allen power plan
This data release presents tabular data and water-level drawdown model files for 32 Mississippi River Valley Alluvial aquifer monitoring wells and 4 Memphis aquifer observation wells from an aquifer test conducted in October 2017 at the Tennessee Valley Authority Allen power plants in Memphis, Shelby County, Tennessee. The dataset contains the water-level model files used to estimate drawdown in t - Connect