Engineering Commons^™

Joint Failure Probability Of Dams Based On Probabilistic Flood Hazard Analysis, Matthew G. Montgomery

Masters Theses

Probabilistic risk methods are becoming increasingly accepted as a means of carrying out risk-informed decision making regarding the design and operation of structures such as dams. Probabilistic risk calculations require the quantification of epistemic and aleatory uncertainties not investigated through deterministic methodologies. In this hydrological study, a stochastic sampling methodology is employed to investigate the joint failure probability of three dams in adjacent, similarly sized watersheds within the same Hydrologic Unit Code (HUC) 6 basin. A Probabilistic Flood Hazard Analysis (PFHA) framework is used to simulate the hydrologic loading of a wide range of extreme precipitation events across the combined …

Experimental Evaluation Of A Honeycomb Structure In Open Channel Flows, Kyle David Hix

Masters Theses

“Designing and controlling open channel flows presents many challenges. One such challenge is energy dissipation. This challenge is currently addressed by several means, including the use of honeycomb structures. Energy dissipation by honeycomb structures has been studied for pressurized conduit flows; however, their ability to dissipate energy in free-surface flows remains largely unexamined. This work introduces a comprehensive experimental study designed to estimate the energy dissipation through a honeycomb structure in a free-surface flow.

This work examined the energy dissipation for a range of flows, pipe lengths, and pipe diameters in two flumes. PVC pipes ranging from 6 inches to …

Exploring The Influence Of Urban Watershed Characteristics And Antecedent Climate On In-Stream Pollutant Dynamics, Laurel Elizabeth Christian

Masters Theses

Understanding pollutant fate and transport in urban watersheds is a challenging endeavor, as heterogeneity of land use, precipitation patterns, and pollutant loadings add complexity to the system. As a result, many currently utilized water quality models exhibit poor performance. One main challenge in urban system modeling is the lack of quality data sets for model development, calibration, and testing, resulting in the need for high quality data collection. Although recent studies have begun to investigate pollutant transport in urban watersheds to aid these models, these studies have focused primarily on the end-of-pipe as the point of interest (i.e. prior to …

Bankfull Geomorphic Relationships And Hec-Ras Assessment In Small Catchments Of The Cumberland Plateau Ecoregion, Ryan Lee Hodges

Masters Theses

There is a great need for state governments to have effective watershed restoration and mitigation efforts to return degraded ecosystems to a stable, healthy condition. Given the growing investment in stream restoration efforts, there is an urgent need for tools to assess and improve the effectiveness of restoration efforts at local, state, and nationwide scales. In 2000 there was less than ten stream restoration permits provided by the state of Tennessee and has increased each year with almost forty permits issued in 2013. To better achieve successful stream restoration, appropriate channel designs must be used that reflect the hydraulic conditions …

Modeling Water Age And Disinfection Byproduct Formation In Drinking Water Distribution Systems In East Tennessee, Seth Adam Fischer

Masters Theses

Chlorine disinfection of drinking waters is responsible for the standard of health we enjoy today and the eradication of waterborne disease. Chlorine also reacts with natural organic matter (NOM) to form disinfection byproducts (DBPs) which have been linked to cancer as well as reproductive and developmental issues. The exact mechanism for formation of regulated DBPs, trihalomethanes (THMs) and haloacetic acids (HAAs), is unknown. The literature has identified relationships between DBP formation and, most notably, characteristics of NOM, chlorine contact time, temperature, pH [negative log of hydrogen ion concentration], and chlorine dose. This study develops models both specific to individual utilities, …

Investigating Instabilities With Hec-Ras Unsteady Flow Modeling For Regulated Rivers At Low Flow Stages, Jennifer Kay Sharkey

Masters Theses

Dams are used throughout the United States for generation of electricity and flood control. The Tennessee River Valley’s regulated river system extends through Tennessee and parts of Kentucky, Mississippi, Alabama, Georgia, North Carolina, South Carolina, and Virginia. Of the dams in this area, 49 are managed by the Tennessee Valley Authority (TVA). The TVA forecasts and monitors the activities related to these dams and others in the area on an around-the-clock basis to ensure maximum generation potential is attained and to prevent flooding of the surrounding cities. To best forecast hydrology for the regulated river system, the TVA chose to …

Chemical Flux During Event Stormwater Flows In The Great Smoky Mountains National Park: Comparison Of Two Streams Varying By Drainage Area And Elevation, Matthew Williams Aplin

Masters Theses

Streams in the Great Smoky Mountains National Park in North Carolina and Tennessee have been impacted by acid deposition from anthropogenic sources for decades. Recent declines in acid deposition throughout the eastern U.S. appear to be initiating improvements in stream water quality. However, watershed recovery could take decades due to regional differences in the hydrologic and biogeochemical processes that influence chemical fate and transport. These processes have been extensively studied at longer time scales (i.e. seasonally, annually), by long-term annual ion budgets, and study designs based on grab samples. Less known are the acidification effects on streams through rapid ion …

Long-Term Evaluation Of Norris Reservoir Operation Under Climate Change, Joseph Patton Rungee Ii

Masters Theses

This study aimed to address the potential long-term effects of future climate change on the Tennessee Valley Authority’s (TVA’s) operation policy for Norris Reservoir. The Community Earth System Model 1.0 (CESM1.0), a general circulation model (GCM) accessible through the Intergovernmental Panel on Climate Change’s (IPCC’s) Coupled Model Intercomparison Project Phase 5 (CMIP5), with the Representative Concentration Pathway 4.5 (RCP4.5) was used to obtain projected precipitation and temperature data for three future climate scenarios, 2030’s, 2050’s, and 2070’s. Three hydrologic models were individually calibrated on 30 years of observed runoff data and combined utilizing linear programming to consider the strengths of …

A Hydrological Analysis Of Switchgrass Land Cover In East Tennessee, Jordan Avery Hayes

Masters Theses

Energy needs and the recent installation of a cellulosic biofuel plant in Vonore, TN have created a demand for switchgrass in East Tennessee. Switchgrass has many strengths such as erosion protection, nutrient removal, and runoff mitigation. The Soil and Water Assessment Tool (SWAT) was selected to model the impact of transitioning traditional crops into switchgrass land cover. Field data was needed to properly calibrate the SWAT model for East Tennessee. The National Resources Conservation Service (NRCS) curve number (CN) was needed for runoff calibrations. This value was determined by both standard NRCS methods as well as an asymptotic method. The …

A Spatial Analysis Of Streambank Heterogeneity And Its Contribution To Bank Stability, Paul Vanterpool Simmons

Masters Theses

Streambank erosion is a function of fluvial detachment and geotechnical failure mechanisms working in combination to cause bank retreat. It is generally agreed that bank stability is dependent on both types of erosion; however, few studies have attempted to correlate the driving and resisting forces between the two. It has been proposed that: (1) streambanks possess a spatial structure and dependence of non-erodible resistant structures such as root masses and rocks; (2) streambanks naturally “armor” themselves from fluvial erosion with a combination of hard points and resistive soil; and (3) the stability of the streambank can be predicted by the …

Estimates Of Glacier Mass Loss And Contribution To Streamflow: Wind River Range (Wyoming, Usa), Jeffrey Allen Marks

Masters Theses

The Wind River Range is a continuous mountain range approximately 160 km in length in west-central Wyoming. The Wind River Range is host to roughly 680 snow and ice bodies with 63 of these considered glaciers including seven of the ten largest glaciers in the American Rocky Mountains. The presence of glaciers results in meltwater contributions to streamflow during the late summer (July, August, and September – JAS) when snowmelt is decreasing, temperatures are high, precipitation is low, and irrigation demand continues. Most studies indicate that the glaciers in the Wind River Range have been retreating since the 1850’s, the …

Impacts Of Beetle Kill On Modeled Streamflow Response In The North Platte River Basin, Jordan Andrew Rudolph

Masters Theses

A beetle epidemic has been sweeping its way across the western United States and into portions of southern Canada that has caused millions of acres of forests to ultimately die. This beetle outbreak, that many have come to know simply as “beetle kill”, has caused many scientists to feel that such dramatic changes in land cover could potentially alter the hydrology throughout much of the West. One of the most important hydrological processes that beetle kill has the potential to impact is streamflow. This paper attempts to evaluate the hydrological impacts on streamflow from land cover change due to beetle …

Two Studies On Controlling The Outflow From Sediment Basins: 1) Developing Discharge Coefficients For Circular Orifices In Round Riser Pipes, And 2) Optimizing The Solid State Skimmer, Alex James Mclemore

Masters Theses

Sediment pollution is a major contributor to stream and river impairment. Often, the source of sediment pollution is from a construction site’s runoff stormwater. A sediment retention basin, especially one with skimming outlet, can help minimize the sediment pollution from constructions sites. A sediment retention basin and outlet are specifically designed for each site to retain as much sediment as possible while satisfying other requirements such as peak flow rates and retention times. Because the modern designs needs have increased requirements, there is an increased need to be as accurate as possible when modeling the hydraulics and the sediment trapping …