Geology topics

Research about Tennessee

Source-linked reports with geographic coverage including Tennessee.

At least 55 records · Page 3Linked to original sources

USGS2021

Reconnaissance of cumulative risk of pesticides and pharmaceuticals in Great Smoky Mountains National Park streams

The United States (US) National Park Service (NPS) manages protected public lands to preserve biodiversity. Exposure to and effects of bioactive organic contaminants in NPS streams are challenges for resource managers. Recent assessment of pesticides and pharmaceuticals in protected-streams within the urbanized NPS Southeast Region (SER) indicated the importance of fluvial inflows from external sources as drivers of aquatic contaminant-mixture exposures. Great Smoky Mountains National Park (GRSM), lies within SER, has the highest biodiversity and annual visitation of NPS parks, but, in contrast to the previously studied systems, straddles a high-elevation hydrologic divide; this setting limits fluvial-inflows of contaminants but potentially increases visitation-driven contaminant deliveries. We leveraged the unique characteristics of GRSM to test further the importance of fluvial contaminant inflows as drivers of protected-stream exposures and to inform the relative importance of potential additional contaminant transport mechanisms, by comparing the estimated risks of 328 pesticides and pharmaceuticals in water at 16 GRSM stream locations to those estimated previously in SER streams. Extensive mixtures (31 compounds) were only observed in an atypical reach on the boundary of GRSM downstream of a wastewater discharge, while limited mixtures (2–5 compounds) were observed in one stream with elevated visitation pressure (recreational “tube floating”). The insecticide, imidacloprid, used to eradicate hemlock woolly adelgid, was detected in 8 (50%) streams. Infrequent exceedances of a cumulative ToxCast-based, exposure-activity ratio (Σ EAR ) 0.001 screening-level of concern suggested limited risk to non-target, aquatic vertebrates, whereas exceedances of a cumulative benchmark-based, invertebrate toxicity quotient (Σ TQ ) 0.1 screening level at 8 locations indicated generally high risk to invertebrates. The results are consistent with the importance of fluvial transport from extra-park sources as a driver of bioactive-contaminant mixture exposures in protected streams and illustrate the potential additional risks from visitation-driven and tactical-use-pesticides.

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USGS2020

Direct and indirect effects of fire on eastern box turtles

Prescribed fire is an increasingly important management tool for eastern deciduous forests, but relativity little is known about the direct effects of fire on the eastern box turtle ( Terrapene carolina carolina ). We used very high frequency (VHF) transmitters to monitor mortality, movement, and spatial ecology of 118 box turtles in response to 17 prescribed fires across 4 seasons and 3 sites in east Tennessee, USA, during 2016–2018. Annual survival of box turtles that experienced a prescribed fire event was lower (0.87 ± 0.04 [SE]) than turtles that did not (0.98 ± 0.01) and was negatively correlated with fire intensity, fire temperature the turtle experienced, and litter depth. All prescribed fire‐related mortalities occurred during the early (Apr–May, n = 5) or late growing season (Sep–Oct, n = 1). Fourteen percent of box turtles we captured exhibited damage to their carapace from previous fire events. Box turtles that survived prescribed fires were in microsites that did not burn, moved to unburned areas during the fire, or burrowed following ignition. Home range size was similar before and after burns and sinuosity of movements did not differ in burned or unburned areas. Our results indicate that though box turtles are susceptible to prescribed fire during their active season, they have behavioral and physical traits that reduce the direct effects of prescribed fire. Prescribed fire practitioners should be aware of the risks of fire, particularly during the active season. We suggest managers consider altering prescribed fire intensity, seasonality, and firing pattern to minimize risk of direct effects where box turtles are of concern.

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USGS2020

Longitudinal distribution of uncommon fishes in a species-rich basin

The spatial organization of fishes in a river system was investigated to evaluate the longitudinal distribution of uncommon species. It was anticipated that overall richness of the fish community would increase in a downstream direction together with habitat extent, but that more uncommon species would occur upstream owing to greater heterogeneity among sites. Fish were collected between 1995 and 2014 at 85 sites distributed throughout the Duck River Basin, Tennessee, USA. A site usually consisted of four habitat types: riffles, runs, pools and shoreline. Each habitat type was sampled with a multipass electrofishing protocol. In all, 136 native fish species were collected. Of these, 71% were classified as uncommon but represented only 16% of the total count of fish collected. As expected, overall species richness increased downstream, but contrary to expectation, uncommon species did too. Some uncommon species were restricted exclusively to tributaries and headwaters, some to tributaries and mainstem, many to mainstem only, but the largest fraction of uncommon species occurred throughout the basin, but even this last group increased in richness downstream. Conservation often focuses on uncommon species. This study suggests that a greater number of uncommon species can be conserved with an emphasis on large downstream reaches, which not only include more aquatic habitat to support larger concentrations of fish, but also shelter the uncomm

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USGS2020

Microbiology and oxidation-reduction geochemistry of the water-table and Memphis aquifers in the Allen well field, Shelby County, Tennessee

The shallow and Memphis aquifers in Shelby County, Tennessee, are valuable natural resources that are used for domestic, public-supply, and agricultural water use. The Memphis aquifer is the primary source for public supply in West Tennessee and provides 170 to 175 million gallons of water per day for more than 900,000 people (Robinson, 2018). The shallow aquifer includes the unconfined water table, provides domestic water supplies in Shelby County, and is susceptible to contamination from urban and industrial activities, underground storage tanks, old dumps, and other sources. Both aquifers are likely to be stressed in the future by factors such as population increase, contaminant migration from historical contamination sites, industrial and agricultural activities, climate change, and other competing demands on the water resources.

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USGS2019

Quantifying contributions to tournament catches among resident, stocked, and hybrid black basses (Micropterus spp.)

Millions of Florida bass, Micropterus floridanus Lesueur, are stocked annually into populations of largemouth bass, Micropterus salmoides Lacepède, to increase trophy fish abundance. However, little effort has related the role that resultant hybrids make to angler catches. Largemouth bass were sampled from an important recreational fishery subject to extensive Florida bass stocking to address the hypothesis that anglers capture Florida bass, largemouth bass and hybrids at rates equivalent to their overall abundance in the population. Fin clips obtained from tournament angling events ( n = 348) and boat-mounted electrofishing sampling ( n = 219) were screened at 38 species-diagnostic markers and individuals were assigned to genealogical classes using Bayesian clustering algorithms. No significant differences were identified between angler and electrofishing catches providing evidence that hybridised individuals stemming from a long-term stocking programme may constitute an important contribution to tournament angling catch.

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USGS2019

Abundance-occupancy patterns in a riverine fish assemblage

The interspecific relationships between abundance and site occupancy have been widely studied in plants and animals, but principally in terrestrial systems. With few exceptions, a positive abundance–occupancy relationship has been reported. Few publications have included freshwater fish, possibly suggesting a general lack of abundance–occupancy patterns for this taxonomic group. We examined the relationship between abundance and the extent of site occupancy by 145 species of freshwater fish, including nine non-indigenous species, sampled over 85 sites spread across the Duck River Basin, Tennessee, U.S.A. A distinct ( r 2 = 0.79) positive abundance–occupancy curve was observed, with curves differing relative to feeding and size guilds, but not relative to environmental tolerance, conservation status (i.e. listed/non-listed), or origin (i.e. indigenous/non-indigenous). The patterns observed are consistent with those reported in many studies of terrestrial taxa. The existence of positive abundance–occupancy relationships in stream fish has at least two major implications for fish conservation. First, species that decrease in occupancy due to anthropogenic disturbances are likely to decrease in abundance, facing inflated prospects for local extinction. Second, occupancy alone may be used to index community status and the need for, or success of, conservation activities.

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USGS2019

A statewide evaluation of Florida Bass genetic introgression in Tennessee

Largemouth Bass (Micropterus salmoides) are one of the most popular freshwater sport fish in the United States and managers in southeastern states have stocked the Florida Bass (M. s. floridanus) subspecies outside of its natural range to increase size structure of existing Largemouth Bass populations. In Tennessee, fisheries for Largemouth Bass are concentrated in reservoirs of the Cumberland and Tennessee River systems; however, Florida Bass stockings have to date been restricted to two reservoirs of the Tennessee River and have varied significantly in extent and duration. We quantified levels of genetic admixture between Florida Bass and Largemouth Bass using 38 species-diagnostic single nucleotide polymorphisms for 979 fish sampled from 14 reservoirs from the Cumberland and Tennessee River systems. We tested for differences in genetic admixture across river systems and evaluated the relative importance of fish stockings in explaining observed levels of genetic admixture. Levels of genetic admixture and associated variation was higher in reservoirs of the Tennessee River (range = 6.3 – 30.4 average percent Florida Bass alleles) relative to the Cumberland River (range = 5.7 – 13.4 %), but admixture was not solely related to stocking rates. The highest levels of Florida Bass introgression were detected in Chickamauga Reservoir, the most extensively stocked reservoir in the state. Linear models identified fish stocked as a significant overall predictor of admixture, but we also observed stocked and unstocked reservoirs with similar levels of admixture, suggesting factors other than stocking influence population genetics. Our statewide assessment of reservoir-level patterns of hybridization among black bass was performed prior to the recent expansion of Florida Bass stocking efforts in Tennessee, and thus, represents a baseline for evaluating future stocking.

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USGS2019

Wetlands and development influence fish diversity in a species-rich small river

We identified in-stream and off-stream characteristics that influenced various species diversity metrics in reaches of the Duck River Basin, Tennessee, USA. This relatively small basin is home to one of the most diverse freshwater fish faunas in North America. In all, over 325,000 native fish representing 136 native fish species were electrofished in 207 collections across 86 stations. Diversity of native species and of seven taxa and functional guilds, including imperiled species, increased with size of the catchment above a station, an effect that was mediated by altitude. After removing the effects of catchment and altitude, diversity was influenced by in-stream factors and mostly by off-stream land composition such as wetlands within 0.1 km from the channel and urban/suburban development within 2.5 km. Pastures next to streams unexpectedly increased diversity. Our analyses suggest that there are detectable hotspots associated with off-stream landscape characteristics where conservation efforts may be focused. Our results may encourage conservation planners to apply geospatial analyses to identify diversity hotspots based on land cover distributions and develop recommendations for management of specific stream reaches. Alternatively, geospatial analysis may be used by planners to estimate the impacts of alternative land-use scenarios, thus preemptively conserving species richness.

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USGS2019

Adapting a regional water-quality model for local application: A case study for Tennessee, USA

We evaluated whether SPAtially Referenced Regression On Watershed attributes (SPARROW) models calibrated for two adjacent USA regions could be applied at the local scale to support management decisions for streams in Tennessee. Nutrient-source apportionment of load is important for this local-scale application and demands careful consideration of uncertainty in the calibrated coefficients. We used Gauss-Newton regression to test the published SPARROW models for constancy of coefficient estimates between calibration sites on streams within (n = 59) versus outside (n = 327) Tennessee and concluded source apportionment was unbiased for Tennessee streams. The SPARROW models were then applied without re-calibration to predict stream loads and source apportionment for Tennessee streams and to build tools for displaying model results and evaluating source-change scenarios. This approach may inform the adaptation of other regional-scale regression models for use to address water-resource management issues in smaller-scale watersheds.

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USGS2018

Spatial organization of fish diversity in a species-rich basin

Many abiotic and biotic environmental characteristics in river basins show spatial gradients from river source to main stem. We examined the spatial organization of fish within the Duck River Basin to document patterns in diversity that could help guide conservation strategies relevant to controlling the detrimental effects of basin development. In all, over 0.33 million fishes representing 145 species and 18 families, including 9 non-native species, were collected in 207 samples distributed throughout the basin. Main stem sites with large catchment areas supported more fish diversity than smaller sites in tributaries. Moreover, rare species were most common in the main stem and ubiquitous species in tributaries. The spatial organization of species assemblages was mostly nested, as assemblages appeared to disassemble in an upstream direction from main stem sites and confluences. These findings suggest that fish conservation efforts might emphasize main stem segments and confluences that support higher biodiversity including the rare species often most in need of protection. The main stem can support the populations needed to recolonize tributaries and rescue populations that might periodically go extinct after droughts or other major disturbances. In tributaries, conservation of species assemblages may focus on managing between-patch connectivity via corridor maintenance or creation.

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USGS2018

Altitude of the potentiometric surface, 2000–15, and historical water-level changes in the Memphis aquifer in the Memphis area, Tennessee

The Memphis and Fort Pillow aquifers are the principal sources of water for municipal, industrial, and commercial uses in the Memphis area. About 207 million gallons per day of groundwater were withdrawn in Shelby County, Tennessee, from both aquifers in 2010 for these uses, with most of the water coming from the Memphis aquifer. The U.S. Geological Survey, in cooperation with the City of Memphis, Memphis Light, Gas and Water Division, collects groundwater-level data in the Memphis area and periodically prepares potentiometric-surface maps for the Memphis aquifer to assess conditions in this regionally important water supply aquifer. This report presents the altitudes of the potentiometric surface of water in wells screened in the Memphis aquifer based on water-level measurements made in the fall of 2000, 2005, 2010, and 2015 and describes historical water-level changes in the Memphis aquifer at key observation wells in the Memphis area. The Memphis area is about 1,500 square miles and includes all of Shelby County and parts of Tipton and Fayette Counties in Tennessee, parts of DeSoto and Marshall Counties in Mississippi, and part of Crittenden County in Arkansas.

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USGS2018

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.

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USGS2018

Public-supply water use and self-supplied industrial water use in Tennessee, 2010

The U.S. Geological Survey (USGS), in cooperation with the Tennessee Department of Environment and Conservation, Division of Water Resources, prepared this report and displayed and analyzed water use by self-supplied industrial and public-supply water systems in Tennessee for 2010. Public-supply water systems in Tennessee provide water for domestic, industrial, and commercial uses and for municipal services. In 2010, 474 public-supply water systems distributed 917 million gallons per day (Mgal/d) of surface water (67 percent, 617 Mgal/d) and groundwater (33 percent, 300 Mgal/d) to a population of 5.7 million in Tennessee. Gross per capita water use in Tennessee during 2010 was 162 gallons per day. Since 1950, water withdrawals by public-supply water systems in Tennessee have increased from 160 Mgal/d to 917 Mgal/d in 2010. Each of the 95 counties in Tennessee was served by at least 1 public-supply water system in 2010. Tennessee public-supply water systems withdraw less groundwater than surface water, and surface-water use has increased at a faster rate than groundwater use. Since 2005, surface-water withdrawals have increased by 26 Mgal/d, and groundwater withdrawals have decreased by 29 Mgal/d, which is the first decrease in groundwater withdrawals since 1950; however, 29 systems reported increased groundwater withdrawals during 2010, and 12 of these 29 systems reported increases of 1 Mgal/d or more. Davidson County had the largest surface-water withdrawal rate (136 Mgal/d) in 2010. The largest groundwater withdrawal rate (151 Mgal/d) by a single public-supply water system was reported by Memphis Light, Gas and Water, which served more than 669,000 people in Shelby County in 2010. Self-supplied industrial water use includes water for such purposes as fabrication, processing, washing, diluting, cooling, or transporting a product; incorporating water into a product; or for sanitation needs in facilities that manufacture various products. Water withdrawals for self-supplied industrial water use during 2010 were about 776 Mgal/d. This quantity represented a decrease of 7 Mgal/d since 2005. In Tennessee, self-supplied industrial water withdrawals were primarily for chemical and allied products (555 Mgal/d), paper and allied products (107 Mgal/d), aeronautical products (71.5 Mgal/d), concrete and glass products (9.74 Mgal/d), and primary metal products (4.49 Mgal/d); and these products accounted for 96 percent (747 Mgal/d) of the self-supplied industrial water withdrawals in 2010. Surface water supplied 94 percent of the water (728 Mgal/d) for self-supplied industrial purposes, and groundwater supplied 6 percent (47.6 Mgal/d). Self-supplied industrial water withdrawals in Sullivan County were 488 Mgal/d and accounted for 61 percent of the self-supplied industrial water withdrawals. The largest groundwater withdrawal, 14.9 Mgal/d, by a single self-supplied industry was in Memphis, Tennessee, for the production of chemicals and allied products.

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USGS2018

Activity of southeastern bats along sandstone cliffs used for rock climbing

Bats in the eastern U.S. are facing numerous threats and many species are in decline. Although several species of bats commonly roost in cliffs, little is known about use of cliffs for foraging and roosting. Because rock climbing is a rapidly growing sport and may cause disturbance to bats, our objectives were to examine use of cliff habitats by bats and to assess the effects of climbing on their activity. We used radio-telemetry to track small-footed bats (Myotis leibii) to day roosts, and Anabat SD2 detectors to compare bat activity between climbed and unclimbed areas of regularly climbed cliff faces, and between climbed and unclimbed cliffs. Four adult male small-footed bats were tracked to nine day roosts, all of which were in various types of crevices including five cliff face roosts (three on climbed and two on unclimbed faces). Bat activity was high along climbed cliffs and did not differ between climbed and unclimbed areas of climbed cliffs. In contrast, overall bat activity was significantly higher along climbed cliffs than unclimbed cliffs; species richness did not differ between climbed and unclimbed cliffs or areas. Lower activity along unclimbed cliffs may have been related to lower cliff heights and more clutter along these cliff faces. Due to limited access to unclimbed cliffs of comparable size to climbed cliffs, we could not thoroughly test the effects of climbing on bat foraging and roosting activity. However, the high overall use of climbed and unclimbed cliff faces for foraging and commuting that we observed suggests that cliffs may be important habitat for a number of bat species. Additional research on bats' use of cliff faces will improve our understanding of the factors that affect their use of this habitat including the impacts of climbing.

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USGS2017

Groundwater/surface-water interaction in central Sevier County, Tennessee, October 2015–2016

The U.S. Geological Survey evaluated the interaction of groundwater and surface water in the central part of Sevier County, Tennessee, from October 2015 through October 2016. Stream base flow was surveyed in December 2015 and in July and October 2016 to evaluate losing and gaining stream reaches along three streams in the area. During a July 2016 synoptic survey, groundwater levels were measured in wells screened in the Cambrian-Ordovician aquifer to define the potentiometric surface in the area. The middle and lower reaches of the Little Pigeon River and the middle reaches of Middle Creek and the West Prong Little Pigeon River were gaining streams at base-flow conditions. The lower segments of the West Prong Little Pigeon River and Middle Creek were losing reaches under base-flow conditions, with substantial flow losses in the West Prong Little Pigeon River and complete subsurface diversion of flow in Middle Creek through a series of sinkholes that developed in the streambed and adjacent flood plain beginning in 2010. The potentiometric surface of the Cambrian-Ordovician aquifer showed depressed water levels in the area where loss of flow occurred in the lower reaches of West Prong Little Pigeon River and Middle Creek. Continuous dewatering activities at a rock quarry located in this area appear to have lowered groundwater levels by as much as 180 feet, which likely is the cause of flow losses observed in the two streams, and a contributing factor to the development of sinkholes at Middle Creek near Collier Drive.

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USGS2017

Streamflow characteristics from modelled runoff time series: Importance of calibration criteria selection

Ecologically relevant streamflow characteristics (SFCs) of ungauged catchments are often estimated from simulated runoff of hydrologic models that were originally calibrated on gauged catchments. However, SFC estimates of the gauged donor catchments and subsequently the ungauged catchments can be substantially uncertain when models are calibrated using traditional approaches based on optimization of statistical performance metrics (e.g., Nash–Sutcliffe model efficiency). An improved calibration strategy for gauged catchments is therefore crucial to help reduce the uncertainties of estimated SFCs for ungauged catchments. The aim of this study was to improve SFC estimates from modeled runoff time series in gauged catchments by explicitly including one or several SFCs in the calibration process. Different types of objective functions were defined consisting of the Nash–Sutcliffe model efficiency, single SFCs, or combinations thereof. We calibrated a bucket-type runoff model (HBV – Hydrologiska Byråns Vattenavdelning – model) for 25 catchments in the Tennessee River basin and evaluated the proposed calibration approach on 13 ecologically relevant SFCs representing major flow regime components and different flow conditions. While the model generally tended to underestimate the tested SFCs related to mean and high-flow conditions, SFCs related to low flow were generally overestimated. The highest estimation accuracies were achieved by a SFC-specific model calibration. Estimates of SFCs not included in the calibration process were of similar quality when comparing a multi-SFC calibration approach to a traditional model efficiency calibration. For practical applications, this implies that SFCs should preferably be estimated from targeted runoff model calibration, and modeled estimates need to be carefully interpreted.

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USGS2017

Prehistoric floods on the Tennessee River—Assessing the use of stratigraphic records of past floods for improved flood-frequency analysis

Stratigraphic analysis, coupled with geochronologic techniques, indicates that a rich history of large Tennessee River floods is preserved in the Tennessee River Gorge area. Deposits of flood sediment from the 1867 peak discharge of record (460,000 cubic feet per second at Chattanooga, Tennessee) are preserved at many locations throughout the study area at sites with flood-sediment accumulation. Small exposures at two boulder overhangs reveal evidence of three to four other floods similar in size, or larger, than the 1867 flood in the last 3,000 years—one possibly as much or more than 50 percent larger. Records of floods also are preserved in stratigraphic sections at the mouth of the gorge at Williams Island and near Eaves Ferry, about 70 river miles upstream of the gorge. These stratigraphic records may extend as far back as about 9,000 years ago, giving a long history of Tennessee River floods. Although more evidence is needed to confirm these findings, a more in-depth comprehensive paleoflood study is feasible for the Tennessee River.

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USGS2017

Sedimentological and petrographic analysis of drill core FC77-1 from the flank of the central uplift, Flynn Creek impact structure, Tennessee

Drill core FC 77‐1 on the flank of the central uplift, Flynn Creek impact structure, Tennessee, contains 175 m of impact breccia lying upon uplifted Lower Paleozoic carbonate target stratigraphy. Sedimentological analysis of this 175‐m interval carbonate breccia shows that there are three distinct sedimentological units. In stratigraphic order, unit 1 (175–109 m) is an overall coarsening‐upward section, whereas the overlying unit 2 (109–32 m) is overall fining‐upward. Unit 3 (32–0 m) is a coarsening‐upward sequence that is truncated at the top by postimpact erosion. Units 1 and 3 are interpreted as debris or rock avalanches into finer sedimentary deposits within intracrater marine waters, thus producing progressively coarser, coarsening‐upward sequences. Unit 2 is interpreted to have formed by debris or rock avalanches into standing marine waters, thus forming sequential fining‐upward deposits. Line‐logging of clasts ranging from 5 mm to 1.6 m, and thin‐section analysis of selected drill core samples (including clasts < 5 mm), both show that the Flynn Creek impact breccia consists almost entirely of dolostone clasts (90%), with minor components of cryptocrystalline melt clasts, chert and shale fragments, and clastic grains. Cryptocrystalline melt clasts, which appear isotropic in thin section, are in fact made of exceedingly fine quartz crystals that exhibit micro‐Fourier transform infrared (FTIR ) and micro‐Raman spectra consistent with crystalline quartz. These cryptocrystalline melt clasts are the first melt clasts of any kind to be reported from Flynn Creek impact structure.

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