Geology topics

Research about Tennessee River

Source-linked reports with geographic coverage including Tennessee River.

11 recordsLinked to original sources

USGS2022

Abundance-occupancy patterns of black bass in an impounded river

A positive relationship has been documented for a wide diversity of taxa between the percentage of transects sampled in which a species is recorded (i.e., occupancy) and the average abundance of the species at transects where recorded. This positive relationship implies that abundance increases faster than occupancy, so populations that occupy more sites also tend to occupy them at higher abundances. Plainly, there is a limit to the sites available for a species to occupy, so as the population expands numerically, abundance at a site must also increase. The pattern may differ across species and geography depending on aspects such as species vital rates, resource use, and resource availability. I investigated abundance–occupancy patterns of three black basses Micropterus spp. in reservoirs of the mainstem Tennessee River, USA. The data set included relative abundance estimates made at 7,237 sites in nine reservoirs sampled during 1997–2018, for 43,243 black bass, including 67% Largemouth Bass Micropterus salmoides , 14% Smallmouth Bass M. dolomieu , and 19% Spotted Bass M. punctulatus . As relative abundance increased due to natural annual population fluctuations, occupancy also increased, but faster for Largemouth Bass and more slowly for Smallmouth Bass and Spotted Bass. Largemouth Bass spread abundance more thinly over many sites, and Smallmouth Bass and Spotted Bass spread abundance more thickly over fewer sites. The recognition that black bass populations that decline in occupancy face the additional burden of disproportionally larger decreases in abundance per site, or that black bass that decline in abundance per site face decreases in occupancy, has various conservation and habitat management implications.

Alabama, Georgia, Kentucky, Mississippi, North Car↗

USGS2021

Improving flood-frequency analysis with a 4,000-year record of flooding on the Tennessee River near Chattanooga, Tennessee

This comprehensive field study applied paleoflood hydrology methods to estimate the frequency of low-probability floods for the Tennessee River near Chattanooga, Tennessee. The study combined stratigraphic records of large, previously unrecorded floods with modern streamflow records and historical flood accounts. The overall approach was to (1) develop a flood chronology for the Tennessee River near Chattanooga using stratigraphic analyses and geochronology from multiple sites at multiple elevations in the study area; (2) estimate peak flow magnitudes associated with elevations of flood evidence using a one-dimensional hydraulic model; (3) combine the information obtained from steps 1 and 2 to develop a history of timing and magnitude of large floods in the study reach; and (4) use all available information (including paleoflood, gaged, and historical records of flooding) to estimate flood frequency using a standardized statistical approach for flood-frequency analysis. The stratigraphy, geochronology, and hydraulic modeling results from all paleoflood sites along the Tennessee River were distilled into an overall chronology of the number, timing, and magnitude of large unrecorded floods. In total, 30 sites were identified and the stratigraphy of 17 of those sites was closely examined, measured, and recorded. Flood-frequency analyses were done using the U.S. Geological Survey software program PeakFQ v7.2 that follows the Guidelines for Determining Flood Flow Frequency—Bulletin 17C. Resolving stratigraphic and chronologic information from all 17 sites yielded information for eight unique large floods in the last 3,500–4,000 years for the Tennessee River near Chattanooga. Two of these floods had discharges of 470,000 cubic feet per second (ft 3 /s), slightly greater than the 1867 historical peak at the Chattanooga streamgage (459,000 ft 3 /s). One flood with a discharge of 1,100,000 ft 3 /s was substantially greater than any other flood on the Tennessee River during the last several thousand years. This large flood occurred only a few hundred years ago, likely in the mid-to-late 1600s. Two additional floods in the last 1,000 years had estimated magnitudes of about 420,000 and 400,000 ft 3 /s. The remaining three unique floods identified in the paleoflood record were much smaller (less than 240,000 ft 3 /s) and occurred about 3,000–800 years ago. Flood-frequency analyses show that the addition of paleoflood information markedly improves estimates of low probability floods—most clearly shown by substantial narrowing of the 95-percent confidence limits. For the most plausible flood scenario, the 95-percent confidence interval for the 1,000-year quantile estimate derived from incorporating the four most recent paleofloods is about 480,000–620,000 ft 3 /s compared to about 380,000–610,000 ft 3 /s for the gaged and historical record alone, a reduction in the uncertainty of the estimate by 38 percent. Similarly, uncertainty for all flood quantile estimates from 100 to 10,000 years was reduced by 22–44 percent by the addition of the paleoflood record to the flood-frequency analyses.

Tennessee↗

USGS2019

Gradients in fish feeding guilds along a reservoir cascade

The river continuum concept predicts a longitudinal gradient in the structure and functioning of rivers. Impoundments potentially change this continuum by reorganizing nutrient transport and storage in the system. To determine if predictions made by the river continuum concept relative to fish assemblage trophic structure hold for a temperate river transformed into a reservoir cascade, we examined longitudinal trends in the distribution of biomass among feeding guilds over 30 reservoirs of the Tennessee River (USA). Fish assemblages were sampled over a 12-year period, and fishes were classified as detritivores, herbivores, invertivores, piscivores, or planktivores. Biomass of all feeding guilds increased with catchment area (i.e., in a downstream direction). However, representation of herbivores and planktivores within the fish assemblage, as indexed by percent biomass composition, increased with catchment area, whereas representation of detritivores, invertivores, and piscivores decreased. In general, the predictions made by the river continuum concept apply to the Tennessee River reservoir cascade despite the major environmental transformation caused by the series of impoundments. However, transformation of lotic into lentic systems promotes autochthonous primary production and proliferation of herbivores and planktivores that reduces relative representation of other guilds. The marked longitudinal pattern in feeding guild structure in the reservoir cascade reflected changes in production sources following impoundment of the river.

Tennessee River↗

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.

Tennessee↗

USGS2017

Gradients in Catostomid assemblages along a reservoir cascade

Serial impoundment of major rivers leads to alterations of natural flow dynamics and disrupts longitudinal connectivity. Catostomid fishes (suckers, family Catostomidae) are typically found in riverine or backwater habitats yet are able to persist in impounded river systems. To the detriment of conservation, there is limited information about distribution of catostomid fishes in impounded rivers. We examined the longitudinal distribution of catostomid fishes over 23 reservoirs of the Tennessee River reservoir cascade, encompassing approximately 1600 km. Our goal was to develop a basin-scale perspective to guide conservation efforts. Catostomid species composition and assemblage structure changed longitudinally along the reservoir cascade. Catostomid species biodiversity was greatest in reservoirs lower in the cascade. Assemblage composition shifted from dominance by spotted sucker Minytrema melanops and buffalos Ictiobus spp. in the lower reservoirs to carpsuckers Carpiodes spp. midway through the cascade and redhorses Moxostoma spp. in the upper reservoirs. Most species did not extend the length of the cascade, and some species were rare, found in low numbers and in few reservoirs. The observed gradients in catostomid assemblages suggest the need for basin-scale conservation measures focusing on three broad areas: (1) conservation and management of the up-lake riverine reaches of the lower reservoirs, (2) maintenance of the access to quality habitat in tributaries to the upper reservoirs and (3) reintroductions into currently unoccupied habitat within species' historic distributions

Tennessee River↗

USGS2015

Land use structures fish assemblages in reservoirs of the Tennessee River

Inputs of nutrients, sediments and detritus from catchments can promote selected components of reservoir fish assemblages, while hindering others. However, investigations linking these catchment subsidies to fish assemblages have generally focussed on one or a handful of species. Considering this paucity of community-level awareness, we sought to explore the association between land use and fish assemblage composition in reservoirs. To this end, we compared fish assemblages in reservoirs of two sub-basins of the Tennessee River representing differing intensities of agricultural development, and hypothesised that fish assemblage structure indicated by species percentage composition would differ among reservoirs in the two sub-basins. Using multivariate statistical analysis, we documented inter-basin differences in land use, reservoir productivity and fish assemblages, but no differences in reservoir morphometry or water regime. Basins were separated along a gradient of forested and non-forested catchment land cover, which was directly related to total nitrogen, total phosphorous and chlorophyll- a concentrations. Considering the extensive body of knowledge linking land use to aquatic systems, it is reasonable to postulate a hierarchical model in which productivity has direct links to terrestrial inputs, and fish assemblages have direct links to both land use and productivity. We observed a shift from an invertivore-based fish assemblage in forested catchments to a detritivore-based fish assemblage in agricultural catchments that may be a widespread pattern among reservoirs and other aquatic ecosystems.

Tennessee River↗

USGS2015

An assessment of sauger population characteristics on two Tennessee River reservoirs

In 1992, a 356-mm minimum length limit (MLL) was enacted on Kentucky Lake and a 381-mm MLL was enacted on Watts Bar Lake, two mainstem reservoirs on the Tennessee River, in an attempt to reduce exploitation and improve the size structure of the sauger (Sander canadensis) populations. The objectives of this study were to compare sauger population characteristics immediately following (1993–1994) and 15 years after (2008–2009) the regulations took effect, examine spatial and temporal patterns in growth, examine recruitment patterns in each reservoir using a recruitment variability index (RVI), and assess the current likelihood of overfishing. Saugers were collected with experimental gill nets in each reservoir and aged using otoliths. A Beverton-Holt yield-per-recruit model was used to simulate angler yields and estimate the likelihood of growth overfishing. Recruitment overfishing was assessed by examining spawning potential ratios under various MLL and exploitation rate scenarios. The sauger population in Kentucky Lake experienced modest improvements in size and age structure over the 15 years following enactment of more restrictive harvest regulations, whereas the population in Watts Bar Lake changed very little, if at all, in terms of size and age structure. Mean lengths of age-3 sauger were significantly greater in Watts Bar Lake than in Kentucky Lake in both time periods. The RVI values indicated that between 1993 and 2009 the sauger in Kentucky Lake displayed more stable recruitment than the Watts Bar Lake population. Neither population exhibited signs of growth overfishing in 2008–09 under the current length limits; however, the Watts Bar Lake population would be susceptible to recruitment overfishing at high (>40%) exploitation rates if natural mortality was as low as 20%. These analyses have demonstrated that the Watts Bar Lake and Kentucky Lake populations, in terms of size and age structure, have remained relatively stable over 15+ years and the MLLs appear to be conserving the stocks.

Tennessee River↗

USGS2013

Water use, availability, and net demand in the Tennessee River watershed within Alabama, 2005

The U.S. Geological Survey worked in cooperation with the Alabama Department of Economic and Community Affairs—Office of Water Resources to estimate water use and water availability for 2005 for the portion of the Tennessee River watershed contained within the borders of the State of Alabama. Estimates of water use and availability are an important part of planning for population and economic growth in the Tennessee River watershed in Alabama. Total water use for the region in 2005 was 5,197 million gallons per day (Mgal/d). Total surface-water withdrawals were 5,139 Mgal/d, and total groundwater withdrawals were about 58 Mgal/d. About 92 percent of the total water withdrawn was surface water used for once-through cooling for thermoelectric power generation. Self-supplied industrial and public-supply water uses accounted for the next greatest uses of water, constituting approximately 49 and 42 percent, respectively, of the total water use excluding thermoelectric power use. Summaries of water use by county and subbasin indicated the areas of greatest water withdrawals and use within the Tennessee River watershed. Limestone (2,012 Mgal/d), Jackson (1,498 Mgal/d), and Colbert (1,363 Mgal/d) Counties were the counties with the greatest total water use in 2005 and had large amounts of water withdrawn for thermoelectric power generation. When water use from thermoelectric power generation was not considered, the counties with the greatest withdrawals were Morgan (124 Mgal/d), Madison (72 Mgal/d), Colbert (69 Mgal/d), and Lawrence (67 Mgal/d). The subbasin with the greatest total water use was Wheeler Lake (2,260 Mgal/d) in the Middle Tennessee—Elk subregion. Wheeler Lake subbasin also had the greatest public-supply, irrigation, industrial, mining, and thermoelectric withdrawals of any subbasin in the Tennessee River watershed within Alabama. Total water availability for the Tennessee River watershed within Alabama was estimated to be 34,567 Mgal/d by the Geological Survey of Alabama. Net water demand for the watershed was calculated by subtracting the Tennessee Valley Authority estimates of return flow from water withdrawals. The net water demand was 136 Mgal/d, which is less than 1 percent of the estimated water available.

Alabama↗

USGS2011

Dispersal and dam passage of sonic-tagged juvenile lake sturgeon in the upper Tennessee River

More than 90,000 state-endangered lake sturgeon (Acipenser fulvescens) have been stocked into the French Broad River, Holston River, and Fort Loudoun Lake in the upper Tennessee River system. Although incidental reports of anglers catching these fish have increased, little is known about their fate after stocking. Therefore, this study was conducted to evaluate lake sturgeon dispersal throughout the system. Seven submersible ultrasonic receivers were deployed in the upper Tennessee River system and 37 juvenile fish (mean fork length = 660 mm) were surgically implanted with ultrasonic transmitters in the fall of 2007. These fish were stocked at two sites in the headwaters of Fort Loudoun Lake. The receivers logged 1,345 detections of tagged fish and manual tracking located 32 of the 37 tagged lake sturgeon over 21 months. Ten (31%) tagged fish passed through Fort Loudoun Dam and were located downstream in the headwaters of Watts Bar Reservoir; the other tagged fish were still at large above Fort Loudoun Dam when tracking ceased in 2009. Of all fish stocked, three (9%) were last located in the French Broad River and none were located in the Holston River.

Tennessee↗

USGS1988

Northern Alabama colonies of the endangered grey bat Myotis grisescens: organochlorine contamination and mortality

From 1976 to 1986, dead and dying grey bats Myotis grisescens and grey bat guano were collected from caves along the Tennessee River in northern Alabama to determine the possible role of organochlorine chemicals — in particular wastes from a former DDT manufacturing plant near Huntsville—in the mortalities. Concentrations of chemical residues in brains were less than known lethal levels; certain observations and analyses did indicate the possibility of past organochlorine-induced bat deaths. Levels of contaminants in bats declined slowly during the 10-year sampling period, but heavy residue burdens persist. The high ratio of DDD to DDE in residues from the former DDT plant made them identifiable as far as 140 km downriver. Grey bats concentrated chemical residues to higher levels and demonstrated the presence of these residues over much greater distances than did red-winged blackbirds Agelaius phoenicus . Grey bats may be the most sensitive indicator available for monitoring the contamination from this former DDT manufacturing site.

Alabama↗

USGS1988

Low-flow profiles of the Tennessee River tributaries in Georgia

Low flow information is provided for use in an evaluation of the capacity of streams to permit withdrawals or to accept waste loads without exceeding the limits of State water quality standards. The purpose of this report is to present the results of a compilation of available low flow data in the form of tables and '7Q10 flow profiles' (minimum average flow for 7 consecutive days with a 10-yr recurrence interval) (7Q10 flow plotted against distance along a stream channel) for all stream reaches of the Tennessee River tributaries where sufficient data of acceptable accuracy are available. Drainage area profiles are included for all stream basins larger than 5 sq mi, except for those in a few remote areas. This report is the fifth in a series of reports that will cover all stream basins north of the Fall Line in Georgia. It includes the parts of the Tennessee River basin in Georgia. Flow records were not adjusted for diversions or other factors that cause measured flows to represent other than natural flow conditions. The 7-day minimum flow profile was omitted for stream reaches where natural flow was known to be altered significantly. (Lantz-PTT)

Georgia↗