Physical Sciences and Mathematics Commons^™

Lithologic Controls On Focused Erosion And Intraplate Earthquakes In The Eastern Tennessee Seismic Zone, Sean F. Gallen, J. Ryan Thigpen

Earth and Environmental Sciences Faculty Publications

We present a new geomorphic model for the intraplate eastern Tennessee seismic zone (ETSZ). Previous studies document that the Upper Tennessee drainage basin is in a transient state of adjustment to ~150 m of base level fall that occurred in the Late Miocene. Using quantitative geomorphology, we demonstrate that base level fall resulted in the erosion of ~3,500 km³ of highly erodibility rock in an ~70 km wide by ~350‐km‐long corridor in the Paleozoic fold‐thrust belt above the ETSZ. Models of modern incision rates show a NE‐SW trending swath of elevated erosion ~30 km southeast of the center of …

East African Weathering Dynamics Controlled By Vegetation-Climate Feedbacks, Sarah J. Ivory, Michael M. Mcglue, Geoffrey S. Ellis, Adam Boehlke, Anne-Marie Lézine, Annie Vincens, Andrew S. Cohen

Earth and Environmental Sciences Faculty Publications

Tropical weathering has important linkages to global biogeochemistry and landscape evolution in the East African rift. We disentangle the influences of climate and terrestrial vegetation on chemical weathering intensity and erosion at Lake Malawi using a long sediment record. Fossil pollen, microcharcoal, particle size, and mineralogy data affirm that the detrital clays accumulating in deep water within the lake are controlled by feedbacks between climate and hinterland forest composition. Particle-size patterns are also best explained by vegetation, through feedbacks with lake levels, wildfires, and erosion. We develop a new source-to-sink framework that links lacustrine sedimentation to hinterland vegetation in tropical …

A Portable Rainfall Simulator For Plot–Scale Runoff Studies, J. Byron Humphry, Tommy C. Daniel, Dwayne R. Edwards, Andrew N. Sharpley

Biosystems and Agricultural Engineering Faculty Publications

Rainfall simulators have a long history of successful use in both laboratory and field investigations. Many plot–scale simulators, however, have been difficult to operate and transport in the field, especially in remote locations where water or electricity is unavailable. This article describes a new rainfall simulator that is relatively easy to operate and transport to and from the field while maintaining critical intensity, distribution, and energy characteristics of natural rainfall. The simulator frame is constructed from lightweight aluminum pipe with a single 50 WSQ nozzle centered at a height of 3 m (9.8 ft). An operating nozzle pressure of 28 …

Tectonic Implications Of Erosional And Depositional Features In Upper Meramecian And Lower Chesterian (Mississippian) Rocks Of South-Central And East-Central Kentucky, Garland R. Dever Jr.

Bulletin--KGS

Erosional and depositional features in upper Meramecian and lower Chesterian (Mississippian) carbonate rocks of south-central and east-central Kentucky suggest the influence of coeval structural activity. The study area, which extends from Pulaski County northeastward into Powell County, is underlain by (1) the Greenwood Anomaly, a large north-trending gravity anomaly, which probably represents part of a Precambrian rift system, and (2) the western part of the Rome Trough, an east-trending graben-like structure, which represents a Late Precambrian to Cambrian continental rift zone. The study focused on the St. Louis Limestone and lower Monteagle Limestone of south-central Kentucky and correlative carbonate rocks …

Use Of Riparian Vegetated Filter Strips To Reduce Nitrate And Fecal Contamination In Surface Water, Mark S. Coyne, Robert L. Blevins, Rebecca A. Gilfillen

KWRRI Research Reports

This research assessed fecal bacteria trapping in surface runoff by grass filters and their potential to enhance NO₃^- removal via denitrification. Grass filter strips 9.0 m long trapped over 99% of the soil in surface runoff in 1992. Fecal coliform removal was less than 75%. In 1993, 9.0 and 4.5 m grass filter strips trapped 99 and 95% of the sediment, respectively. Fecal coliform trapping efficiency was 90% in 9.0 m grass filters and 75% in 4.5 m filters. Fecal streptococci trapping efficiency was 77% in 9.0 m grass filters and only 56% in 4.5 m filters. Fecal …

Impact Of Riparian Grass Filter Strips On Surface-Water Quality, Alex W. Fogle, Daniel I. Carey, Billy J. Barfield, Robert L. Blevins, Vasilios P. Evangelou, Cora E. Madison, Shreeram P. Inamdar

Information Circular--KGS

The effectiveness of natural riparian grass filter strips in removing sediment and agricultural chemicals from surface runoff was studied using no-tillage and conventional-tillage erosion plots. Runoff from the tillage plots was directed onto 4.57, 9.14, and 13.72 m (15, 30, and 45 ft.) length filter strips, where the inflow and outflow concentrations and sediment size distributions were measured. Trapping efficiencies for sediment and agricultural chemicals typically ranged near or above 90 percent, mainly because of high infiltration rates. The filters also significantly reduced peak discharge concentrations, which reduced the impact of sediment and agricultural chemicals on receiving surface waters.

Channel, A Model Of Channel Erosion By Shear, Scour And Channel Headwall Propagation: Part 1. Model Development, Alex W. Fogle, Billy J. Barfield

KWRRI Research Reports

In the research conducted under this project, models were developed which predict channel erosion resulting from shear in gradually varied flow, shearing forces resulting from submerged jets and hydraulic jumps, and shearing forces resulting from free jets impinging a plunge pool. These models are linked with a runoff routing algorithm to develop the CHANNEL model. This model predicts general channel erosion resulting from time varying gradually varied now as well as predicts the development and propagation of channel headwalls. At this writing, the model still has some problems handling the transition from open channel now to a free jet within …

Developing Efficient Crop Production Systems, Kenneth L. Wells

Soil Science News and Views

Land is initially the most limiting resource to consider in setting up a farm system aimed at maximizing returns. This is because soil, its topographical features, and its physical and chemical properties are largely fixed. There is little which can be done about them except to manage soil fertility and control erosion. Over the long run, crop production from any land tract will be directly influenced by the nature and character of the soils in that land tract. For this reason, the most basic step in initiating or redesigning a farming operation is to get an evaluation of the soil …

Mineralization And Hydrocarbon Emplacement In The Cambrian-Ordovician Mascot Dolomite Of The Knox Group In South-Central Kentucky, Warren H. Anderson

Report of Investigations--KGS

The Mascot Dolomite, the upper unit of the Cambrian-Ordovician Knox Group, is a major host for Mississippi Valley-type ore deposits and petroleum in south-central Kentucky. The Mascot was deposited on a broad, shallow platform that exhibited unusually uniform conditions of deposition, ranging from supratidal to shallow subtidal environments. The formation has a complex diagenetic history, including several stages of dolomitization, silicification, solution, and brecciation. Diagenesis and, to some extent, deposition were influenced by Early Ordovician tectonic activity. Tectonic activity influenced development of a regional unconformity during Middle Ordovician time. Evidence of this tectonic activity includes up to 300 feet of …

Modeling Soil Erosion With Emphasis On Steep Slopes And The Rilling Process, Michael C. Hirschi, Billy J. Barfield, Ian D. Moore

KWRRI Research Reports

A soil erosion model, known as KYERMO, was developed for use in soil erosion research. The model was written in Microsoft FORTRAN, which is a subset of the ANSI FORTRAN 77 standard, allowing the model to be run on an IBM-PC as well as a mainframe computer. The model structure consisted of many interrelated subroutines which facilitated model development, testing, and future expansion.

A sensitivity analysis of the detachment component was performed, examining the number of rills, the number of space and time steps, and the detachment parameters. This analysis indicated that the model performed as expected for the detachment …

Modeling Erosion On Long Steep Slopes With Emphasis On The Rilling Process, Michael C. Hirschi, Billy J. Barfield, Ian D. Moore

KWRRI Research Reports

A model of soil erosion, known as KYERMO, is presented which emphasizes those processes which are important on steep slopes. Particular emphasis is placed on modeling rill development and geometry since this is the least understood process in erosion mechanics. The model requires an input rill pattern.

Rainfall inputs to the model require the use of breakpoint rainfall and kinetic energy. Surface storage is calculated based on random roughness data of Linden (1979). Infiltration is modeled by use of the two layer Green-Ampt-Mein-Larson model as proposed by Moore and Eigel (1981). Runoff is related to rainfall excess and surface storage …