English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

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. Introduction Understanding the extent and magnitude of hydraulic connection between aquifers is essential for efficient and sustainable use of groundwater resources. Key factors regarding this issue include the purposes and magnitude of groundwater use, and the contrasts in water quality and the potential connection between aquifers. In the Memphis area in Shelby County, Tennessee, large withdrawals for public and industrial supply have resulted in movement of groundwater from the shallow, “water-table” aquifers into the underlying Memphis aquifer in areas where the upper Claiborne confining unit is thin or absent (Graham and Parks, 1986; Parks, 1990). Proposed withdrawals from the Memphis aquifer at the newly constructed Tennessee Valley Authority (TVA) Allen Combined Cycle (ACC) Plant in southwestern Memphis (fig. 1) has caused public concern about the potential for degradation of the drinking-water supply. Those concerns were heightened by the identification of elevated concentrations of arsenic and other trace metals in the overlying Mississippi River Valley alluvial (MRVA) aquifer at the TVA Allen Fossil (ALF) Plant (Charlier, 2017). In 2017, the U.S. Geological Survey (USGS), in cooperation with the TVA and the University of Memphis, Center for Applied Earth Science and Engineering Research (CAESER), conducted a preliminary investigation of the hydrogeology, groundwater quality, and potential for hydraulic connection between the MRVA and Memphis aquifers in the area. 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 By John K. Carmichael,1 James A. Kingsbury,1 Daniel Larsen,2 and Scott Schoefernacker2 1U.S. Geological Survey. 2University of Memphis. 2 Hydrogeology and Groundwater Quality, Tennessee Valley Authority Allen Power Plants

u.s. geological survey open file report/open-file report

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