Hydrology Commons^™

Characterizing Microplastics In Flood Sediments After Hurricane Helene In Asheville, North Carolina, Abigail Sgan

All Theses

Microplastics are contaminants of emerging concern whose ubiquity across natural environments results in their involvement in many kinds of natural processes, including transportation and deposition in natural systems. The purpose of this thesis is to characterize microplastics and determine the mechanisms that affect their distribution, transport, and sequestration within known Hurricane Helene flood deposits in fluvial and Southern Appalachian wetland environments after Hurricane Helene in Asheville, North Carolina. Four fluvial and four Southern Appalachian wetland environments were sampled after Hurricane Helene. Samples collected in fluvial environments were taken as grab samples from surficial sandy flood deposits left behind by flooding …

Implementation Of A Practical Sharp Interface Saltwater Intrusion Model To Assess Future Sea-Level Impacts, Alexandra G. Defalco

All Theses

Rising sea levels caused by global warming exacerbate saltwater intrusion, the inland movement of seawater into coastal aquifers. These processes increase susceptibility to freshwater contamination, surface flooding, and infrastructure damage. Numerical models are utilized to assess hazards to coastal aquifers on a regional scale.

The U.S. Navy is currently developing a robust, reduced-order groundwater modeling platform, SWI6, that uses the sharp interface approach to approximate the location of the freshwater-saltwater interface to define the extent of saltwater intrusion within an aquifer. Featuring compatibility with MODFLOW 6 unstructured grid formats and the Newton-Raphson formulation for better solution stability, SWI6 improves upon …

Spatially Mapped Statewide Estimated Potential Evapotranspiration Using An Efficient Surface Interpolation Method: A Case Study Of South Carolina, Sudhanshu S. Panda, Devendra M. Amatya, Ka Kit Liu, Augustine Muwamba, Timothy J. Callahan

Journal of South Carolina Water Resources

Potential evapotranspiration (PET) exhibits substantial spatial and temporal variability across large landscapes, necessitating site-specific estimation for accurate environmental and water resource assessments. However, obtaining PET or ET data for specific locations across an entire state remains challenging due to the limited number of weather stations and associated environmental datasets. This study aimed to develop an automated geospatial modeling framework to map PET distribution across South Carolina, USA, using PET estimated by the temperature-based Hargreaves–Samani (H–S) method with daily weather data from 59 NOAA stations. Because the accuracy of spatial interpolation depends on both the target variable and the desired spatial …

Stream Temperature Responses To Summer Urban Rain Events Along The Savannah River, Joseph E. Wermter, Vivian L. Turner, Max K. Appelbaum, James M. Shepherd, Jacob Z. Lott

Journal of South Carolina Water Resources

The hydrological urban heat island (HUHI) is a recent facet of the urban heat island (UHI), describing thermal enhancement of bodies of water in response to urbanization. Although the forefront of this work has been studied for large Metropolitan areas, this effect on developing cities is currently unknown. To locally measure and quantify HUHI effects in a developing city, we utilized Multi-Radar Multi Sensor (MRMS) radar-derived rainfall data to estimate rainfall in the Augusta Metropolitan Area (AMA) and the Savannah Metropolitan Area (SMA), two developing communities adjacent to the Savannah River. We analyzed mean temperature trends of two stream gauges …

Heat Storage Using High Temperature Borehole Heat Exchangers, Jack Horvath

All Theses

The use of renewable energy sources such as wind and solar power is growing, and with it comes an increased need to store excess energy when it is generated and release it on demand. Moderate temperature thermal energy storage in the subsurface is widely used to heat buildings, but high temperatures, greater than 120℃, are required to power generators that convert stored heat to electricity. High temperature heat can be generated from solar collectors or other means and then transferred to the subsurface using borehole heat exchangers (BHE). A BHE consists of a closed-loop pipe system used to circulate a …

Investigating Crystalline Rock Weathering In Distinct Climate And Ecological Settings: Insights From Shallow Seismic Refraction, Rachel Uecker

All Dissertations

Despite decades of research, understanding the subsurface of the critical zone (CZ) remains a challenge, constrained by limited access to information at depth. Traditionally, boreholes, outcrops, soil pits, and near-surface (<1 meter) geochemical measurements provided access to and quantified CZ structure. These methods, though valuable in their detail, are spatially limited, and many landscape-scale weathering hypotheses are based on these observations. In recent years, geophysical techniques have been applied to characterize large-scale CZ structure and test the validity of existing hypotheses. This dissertation harnesses nearly 10 kilometers of seismic refraction data from diverse ecoregions across the United States to challenge prevailing assumptions about weathering patterns and CZ evolution. The objective of this work is to characterize the interpreted range of weathered materials in each ecoregion and connect them to remotely-sensed information like canopy height, elevation, slope, and aspect. To do this, this work first investigates differences in weathering at depth in a north and south-facing slope system in the Laramie Range, Wyoming. The motivation for this work came from nearly a century of soil and geochemical studies from the western United States that show a greater degree and depth of weathering on north-facing slopes when compared to south-facing slopes. Our seismic refraction data were used to show that there is not a significant difference in weathering thickness at depth between north and south-facing aspects at the study site, thus conflicting with the hypothesis that there would be. Next, the hypothesis that the depth of weathering is affected by elevation was tested in the San Jacinto Mountains in southern California. The motivation for this work came from several geochemical studies in the Sierra Nevada Mountains that show ecologically prosperous mid-elevations possess an ideal combination of temperature and precipitation to produce a greater degree and depth of weathering. Again, the seismic results from the San Jacinto Mountains provided observations that conflict with the existing hypothesis that climate conditions dominate the thickness of weathering seen in rocks. Lastly, I used seismic refraction data and topographic curvature to build a groundwater model of a watershed in the Carolina Piedmont. The results of this model reveal that seismic refraction as an application for including more realistic geometry in groundwater models can improve model calibration fits. This model is the first of its kind, and, therefore, is an important step forward in merging geophysical data with the hydrogeologic and modeling field and, with further development, can be used to explore the role of topographic and regional groundwater flow as a driver of CZ evolution.

Leveraging High-Frequency Water Quality Data And Machine Learning For Monitoring Harmful Algal Blooms, Ibrahim Busari

All Dissertations

Freshwater management is one of the most critical resources on the earth due to the plethora of water use and its limited availability. Increased algae proliferation is one of the significant problems of freshwater bodies that is triggered by nutrient enrichment and enabling conditions such as light and warm temperatures. This algal proliferation is toxic to the ecosystem through their biomass and potential toxin production that can cause hypoxic conditions and is often referred to as Harmful Algal Blooms (HABs). Current monitoring approaches include laboratory analysis of water samples to observe algal cells, monitoring of water quality parameters using water …

Evaluation Of Future Sea-Level Impacts Using A Sharp Interface Saltwater Intrusion Model, Caroline Hiott

All Theses

Saltwater intrusion is a growing problem that is being exacerbated by climate change. Saltwater intrusion is the process by which saltwater moves towards freshwater supplies driven by saltwater’s greater density compared to freshwater. Saltwater intrusion can contribute to the salinization of freshwater resources, degradation of underground storage tanks, communication systems, and pipelines, as well as lead to groundwater flooding (Ketabchi et al., 2016). Numerical modeling can be used to simulate saltwater intrusion along coastal areas. One of the more computationally efficient modeling tools is the sharp interface approach, SWI2, that is a part of the MODFLOW 2005 suite (Werner et …

Using Strainmeters To Characterize Enhanced Geothermal Systems, Clem Laffaille

All Theses

none

Measurement Of Microplastics In A Freshwater Micro-Watershed, Cole Bowman

All Theses

The role of microplastics as an emerging contaminant can be complex to study because of the lack of standardization in the collection and analysis of microplastic particles. The purpose of this manuscript is to detail an iterative process of different collection methods in trying to understand microplastic deposition and transport in a freshwater micro-watershed through lab-based and field-based studies. A flume experiment was conducted to test the trapping efficiency of a sediment trap design at two different velocities (1.12 m/s and 2.24 m/s). Eight types of microplastics varying in morphology and density were introduced to the flume in order to …

High-Energy Storm Events And Their Impacts On Carbon Storage In Tidal Wetlands Of South Carolina, Gavin Gleasman

All Dissertations

Atmospheric carbon dioxide (CO₂) concentrations have been increasing at an accelerating rate for the past two centuries, profoundly impacting global climate change. Atmospheric CO₂ concentrations are influenced by the global carbon cycle through physical and biogeochemical pathways. Tidal wetland environments play a vital role in the global carbon cycle by offsetting atmospheric CO₂ concentrations through their natural physiochemical processes of high autotrophic productivity, allochthonous organic matter deposition, anoxic soils, and continuous accretion which promotes carbon sequestration with long-term storage at the land-ocean margin. The Intergovernmental Panel on Climate Change (IPCC) and United States Global Change Research …

Evaluation Of Zero-Net-Rate Pumping Tests, Austin Smith-Jones

All Theses

Accurately estimating the distribution of aquifer properties is key to understanding contaminant movement in the subsurface. The distribution of aquifer properties is typically addressed using slug or constant-rate well tests, and the pros and cons of these tests are well known. Slug tests are appealing because they avoid removing contaminated water, but their results are affected by well skin and the small volume of displaced water limits the volume of aquifer that can be evaluated. Constant-rate well tests have the disadvantage of requiring disposal of potentially contaminated water, but they can generate properties that are more representative than slug tests, …

Explaining Spatio-Temporal Evolution Of Extreme Hydro-Climatic Events Using A Complex Network Framework, Somnath Mondal

All Dissertations

Severe hydroclimatic extreme events, such as droughts, heatwaves, and heavy rainfall, are occurring with increasing frequency and causing significant impacts on both people and the environment. These events also compound in space and time, leading to even more significant consequences. Therefore, it is essential to comprehend these phenomena' concurrent and time-delayed progression across different temporal and spatial scales to address adaptation and mitigation effectively. To accurately understand and map the co-evolution of extreme events, it's necessary to have a thorough grasp of their spatiotemporal patterns, how they propagate and interact with one another, and the underlying mechanisms driving their occurrence. …

Application Of A 14c-Assay To Assess Methanotrophic Biodegradation Of Tce In Low Ph Groundwater, Evan Groome

All Theses

Current biological strategies for remediating trichloroethylene (TCE) in low pH aquifers (i.e., pH14C-TCE assay was developed to determine pseudo first-order rate constants for the degradation of TCE in microcosms containing soil and groundwater from the Boeing Michigan Aeronautical Research Center (BOMARC) superfund site, where the pH ranges from 4.1 to 4.9. The ¹⁴C-TCE assay was also adapted to calculate soil-normalized rate constants for data from this site, as well as data that Szwast²¹ collected from the Beltsville Agricultural Research Center (BARC). In addition to natural attenuation, biostimulation through amendments of methane and nutrients were also assessed. This treatment …

Fate And Transport Of Toxoplasma Gondii Oocysts In Saturated Porous Media: Effects Of Electrolytes And Natural Organic Matter, Christian Pullano

All Theses

Toxoplasma gondii is a pathogenic microorganism that is currently a threat to public health. Understanding the fate and transport of T. gondii through the soil and groundwater is vital in determining the risk it poses to water resources and human health. The physico-chemical interactions between the groundwater and the bio colloid within an aquifer will dictate its mobility and its ability to infect humans. This research examines how various naturally occurring groundwater chemistries containing organic compounds and monovalent and divalent salt solutions will alter the fate and transport of T. gondii. Solutions containing various concentrations of humic acid, fulvic …

Wetland Uranium Transport Via Iron-Organic Matter Flocs And Hyporheic Exchange, Connor J. Parker

All Dissertations

Uranium (U) released from the M-Area at the Department of Energy Savannah River Site into Tims Branch, a seasonal wetland and braided stream system, is estimated to be 43,500 kg between 1965 and 1984. The motivation for this work is the uranium’s persistence in the wetland for decades, where it is estimated that 80% of the U currently remains in the Tims Branch wetland. U has begun to incorporate into wetland iron (Fe) and carbon cycles, associating with local Fe mineralogy and deposits of rich wetland organic matter (OM). The objective of this work is to characterize the chemical phases …

Characterization Of Water Flow And Solute Transport Driven By Preferential Flow In Soil Vadose Zone, Abdullah Al Mamun

All Dissertations

The vadose zone acts as a buffer zone between the ground surface and the aquifers underneath and controls the transmission of infiltrating water and contaminants, for example, pesticides and chemical spills. Therefore, understanding the flow and transport processes that dominate the vadose zone is important. Macropores are ubiquitous and particularly found in abundance in the vadose zone. These macropores facilitate preferential flow, through which water travels rapidly deep into the soil, bypassing most of the porous matrix. Preferential flow and transport have environmental significance as their processes impact hydrology, ecology, agriculture, subsurface contamination, and waste management sectors. Thus, the overall …

Reinforcement Learning Policy Gradient Methods For Reservoir Operation Management And Control, Sadegh Sadeghi Tabas

All Theses

Changes in demand, various hydrological inputs, and environmental stressors are among issues that water managers and policymakers face on a regular basis. These concerns have sparked interest in applying different techniques to determine reservoir operation policy and improve reservoir release decisions. As the resolution of the analysis rises, it becomes more difficult to effectively represent a real-world system using traditional approaches for determining the best reservoir operation policy. One of the challenges is the “curse of dimensionality,” which occurs when the discretization of the state and action spaces becomes finer or when more state or action variables are taken into …

Air-Regulated Siphon Spillways: Performance, Modeling, Design, And Construction, Joshua Boatwright

All Theses

1:Little data exists in the literature for quantification of siphon spillway performance. Proper design of an air regulated siphon spillway requires knowledge of required flow rates and minimum vent size. A set of small siphon spillways were constructed to measure flow rate and required vent size relative to physical characteristics including pipe diameter, length of pipe, and elevation head. Vent sizing was shown to be logarithmically proportional to flow rate. Results were used to develop predictive models for flow rate and vent sizing. Models were validated and refined through testing on a siphon spillway installed on a pond at LaMaster …

Assessment Of The Rainfall Response On Headwater Streams In Lower Coastal Plain South Carolina, Thomas Epps

All Theses

Toward the goal of the assessment of the rainfall response on forested headwater catchments in the Lower Coastal Plain (LCP) of South Carolina, rainfall, streamflow, and groundwater elevation were monitored on two similar streams. Upper Debidue Creek (UDC) in coastal Georgetown County, South Carolina is slated for development and Watershed 80 (WS80) in the Francis Marion National Forest serves as an undeveloped reference watershed. Spatial rainfall variability was assessed at UDC and it was concluded that a single gage was sufficient to accurately measure rainfall for this watershed. Throughfall measurements at UDC indicate a seasonal difference that may influence seasonal …

Treatment Of Oilfield Produced Water Using A Pilot-Scale Constructed Wetland Treatment System, Michael Pardue

All Theses

In recent years production of oil in sub-Saharan Africa has generated thousands of barrels of oilfield produced water (OPW). If water produced from oilfields in sub-Saharan Africa can be treated, this large volume of water has the potential for use in irrigation, which could decrease demand on existing water resources. In this investigation a pilot-scale constructed wetland treatment system (CWTS) consisting of three series: a free water surface flow (FWS) series, a subsurface flow (SSF) series, and a hybrid SSF series preceded by an oil-water separator (OWS), was utilized to treat OPW. Two major objectives were to: 1) assess treatment …

Subsurface Characterization Using Ground-Penetrating Radar In A Hydrologically Active Vadose Zone, Adam Mangel

All Theses

Three experiments were conducted to measure the ability of ground-penetrating radar (GPR) to non-invasively determine water content while simultaneously resolving depth to wetting fronts, buried objects, and stratigraphic boundaries during dynamic hydrologic conditions. This is particularly appealing as GPR can provide dense spatial coverage for vadose zone characterization where traditional invasive measurements are costly, destructive, and time-consuming. The vadose zone was replicated using a tank filled with 1) homogeneous river sand, 2) homogeneous river sand with an embedded land mine surrogate, and 3) homogeneous river sand with an embedded layer of silica flour. These systems were subjected to controlled irrigation …

Pilot-Scale Constructed Wetland Treatment System For Ammonia Removal From Oil-Field Produced Water, Yun Song

All Theses

This investigation examined the feasibility of using free-water surface constructed wetland systems (CWTSs) to decrease the ammonia concentration in oil-field produced water. The objective of this research was to design constructed wetland experiments to determine specific conditions that decrease aqueous ammonia concentrations in simulated oilfield produced water. The design of these experiments was based on biogeochemical pathways of nitrification and denitrification. The experiments included three scales: bench-scale, single-cell, and pilot-scale. Bench-scale reactors contained wetland plants (Typha latifolia) and hydrosoil in 5-gallon buckets. Single wetland cells were constructed by adding hydrosoil and plants (T. latifolia and Schoenoplectus californicus) to 70-gallon containers. …

A Synthetic Analysis Of Integrated Data Fusion: Combining Hydrologic And Geophysical Data Collected During A Tracer Test To Estimate Aquifer Flow And Transport Parameters, Dylan Fowler

All Theses

Integrated data fusion (IDF), also known as coupled inversion, is becoming a more widely used method for estimating hydrologic parameters from geophysical data. IDF is being used in this research as an approach to inversion that couples mathematical models of groundwater flow, solute transport, and electrical resistivity for the direct estimation of hydraulic conductivity, porosity, and dispersivity from transient resistivity data collected during a tracer test. In this work, synthetic field resistivity data are generated using only a single current electrode pair and many potential electrodes. This data is then used within the IDF framework to a) estimate hydraulic conductivity …

Evaluation Of A Pilot-Scale Constructed Wetland Treatment System For Renovation Of A Specific Oilfield Produced Water For Beneficial Use, Jennifer Horner

All Theses

Oilfield produced waters (OPWs) are brought to the surface when oil reservoirs contained in water-bearing geologic units are extracted. Large volumes of OPW present environmental challenges concerning disposal, as well as potential opportunities for beneficial use if constituents posing risk can be remediated. In this study a pilot-scale constructed wetland treatment system (CWTS) was specifically designed to treat an OPW from sub-Saharan Africa for use in irrigation and livestock watering. Three major objectives were to: characterize and identify constituents of concern in the OPW in terms of beneficial use, evaluate treatment performance of a pilot-scale constructed wetland treatment system for …

Identification Of Patterns And Controls Of The Distribution Of Groundwater Discharge To Streams, Curtis Gebhard

All Theses

Groundwater discharge is a key component in understanding the interaction between groundwater and surface water. It provides baseflow to streams and can transport nutrients and contaminants to related aquatic ecosystems. It can also influence fish behaviour, spawning, migration and provide areas of refuge during summer and winter months. There are a variety of techniques that are used to characterize the magnitude of groundwater discharge including seepage meters, field permeameters, and piezometers and manometers, however the controls for the magnitude and distribution of discharge remain poorly understood. The purpose of this study was to conduct field investigations complimented with numerical analysis …

The Dependence Of Electrical Resistivity, Saturation And Saturation Exponent On Multi-Phase Flow Instability, Zuolin Liu

All Theses

Multiphase flow channeling in oil reservoirs during water floods reduces oil recovery. Electrical methods may be used to monitor reservoirs and detect the onset of channeling, but the dependence of electrical resistivity on reservoir flow conditions is complex. The present study is directed toward understanding how the parameters of Archie's law, a commonly assumed relationship between electrical resistivity and water saturation in a porous medium, depends on multiphase flow instability leading to flow channeling. In this research a series of 34 flow experiments were conducted in a thin, two-dimensional tank (55cm x 55cm x 3.75cm) packed with 2mm glass beads …

Predicting Long-Term Well Performance From Short-Term Well Tests In The Piedmont, David Hisz

All Theses

A reliable estimate of the physically sustainable discharge of a well is a fundamental aspect affecting management of water resources, but there are surprisingly few analyses describing on how to make such an estimate. Current available methods include either an empirical or a quantitative approach. The empirical method is based on holding the head or flow rate constant in order to maintain a target drawdown for as long as possible. The second method involves conducting a constant rate test to calculate the properties of the aquifer, T and S, and extrapolate the drawdown using a type curve (i.e. Theis analysis). …

The Impact Of Water Harvesting On A Small Watershed In Rural India, Daniel Matz

All Theses

Reliable sources of fresh water are a finite resource across the world. Many countries, including India, face water scarcity due to temporal and spatial variations in precipitation, surface water pollution, and depletion of groundwater resources. In order to combat against water scarcity, the government, non-governmental organizations, researchers, and individuals have attempted to create solutions to the water scarcity problem. One solution, which has become popular throughout India is the construction of water harvestings structures (WHS), small earthen dams built to capture monsoonal runoff on ephemeral streams. Villagers believe these structures have a positive effect on groundwater levels and water availability …

A Study Of Coastal Headwater Stream Hydrology: Bannockburn Plantation, Georgetown County, Sc, Drake Rogers

All Theses

Coastal headwater streams in undeveloped forested landscapes function as a natural storage and conveyance mechanism for rainfall and groundwater. Stream flows are often driven by groundwater table depth, while soil saturation with a high water table may drive rainfall response. Evapotranspiration also plays a significant role in groundwater levels and influences stream flows both seasonally and diurnally. The dynamics of coastal forested watersheds are complex, and water budgets of these low gradient headwater streams are difficult to quantify.
Understanding these hydrologic dynamics is critical to water resources protection and flood prevention in coastal landscapes, especially as forested areas are converted …