Master of Science (MS), Ohio University, 2024, Geological Sciences

This study investigates the extent, nature, and formation processes of Paleo Lake Buckeye during the Late Pleistocene, located in the Buckeye Creek watershed in the central Appalachian Mountains. This thesis integrates GIS mapping, field methods utilizing sediment coring and trenching, radiocarbon dating and grain size analysis to reconstruct the margins and depositional environments of Paleo Lake Buckeye and its surrounding landscape. Radiocarbon and optically stimulated luminescence (OSL) dating indicate that the lake formed between 20,000 and 40,000 years ago, coinciding with the peak of the last glacial epoch. The stratigraphic analysis shows fine-grained lacustrine deposits, organic rich layers, and episodic coarse-grained beds, which reflects periods of quiet water deposition interrupted by high-energy events. Paleo Lake Buckeye's formation is linked to periglacial conditions, where freeze thaw cycles mobilized sediments and permafrost dynamics influenced hydrological processes. This research not only interpret the paleoenvironmental conditions of the Buckeye Creek watershed during the Late Pleistocene, but also contributes to broader discussions on glacial and periglacial processes, climate variability, and landscape evolution in the central Appalachian Mountains.

Committee: Gregory Springer (Advisor); Katherine Fornash (Committee Member); Eva Lyon (Committee Member) Subjects: Environmental Geology; Environmental Science; Geochemistry; Geographic Information Science; Geography; Geological; Geology; Geomorphology; Paleoecology; Paleontology

MS, Kent State University, 2024, College of Arts and Sciences / Department of Earth Sciences

Anthropogenic macro debris, otherwise known as trash, in urban streams is a persistent environmental problem throughout the world. The factors influencing trash accumulation within US urban stream channels has not been thoroughly investigated, with previous studies focusing largely on surrounding land use. I hypothesized that fluvial geomorphology is a better predictor of trash concentration than GIS-derived variables and that increased geomorphic complexity of stream reaches is associated with higher trash concentrations in urban streams. To test these hypotheses, I examined the relationships between in-stream trash concentrations and different geomorphologic characteristics, catchment characteristics, and catchment and riparian land cover in Cleveland (Ohio) and Charlotte (North Carolina) streams. I collected data on trash (>5 cm), large wood, cross-section and longitudinal profiles, and sediment sizes in 24 urban stream reaches, and calculated 19 geomorphic complexity metrics. Catchment characteristics and land cover variables were derived using ArcGIS Pro. Single and multiple regression approach have been used to find relationships between trash concentration and predictor variables. Trash concentrations ranged from 0.18 to 4.7 pieces/m bankfull width, with an average of 1.55 pieces/m. 71.8% of the collected trash was plastic. More variation in trash concentrations across stream reaches was explained through geomorphologic variables as compared to GIS variables when city-specific multiple linear regression models were made. When data from the two cities were combined, the opposite was true. Cross-section characteristics, especially bankfull width, were amongst the strongest predictors of trash concentration in both cities. Longitudinal profile and sediment characteristics were not predictive of trash concentration for Cleveland streams, and these data were not collected in Charlotte. Therefore, my hypothesis that more trash will be found in streams with more geo (open full item for complete abstract)

Committee: Timothy Gallagher (Advisor); Anne Jefferson (Committee Member); Christie Bahlai (Committee Member) Subjects: Geomorphology; Hydrology; Water Resource Management

Master of Science (MS), Ohio University, 2024, Geological Sciences (Arts and Sciences)

Sediment transport affects how cave passages grow and behave during floods. Sediment begins moving once a critical shear stress is reached. Often, assumptions about variables affecting shear stress are necessary to model sediment transport and a variety of methods have been used to calculate shear stresses to determine when sediment transport is likely to occur. I studied sediment transport in a narrow, steep vadose passage in Fullers Cave, located in Greenbrier County, West Virginia, USA. Flow depth measurements by five in-cave probes were used with known discharges to reconstruct stream processes and sediment transport along a 95-meter reach. A sediment trap and sediment tracing were used to monitor sediment movement. To date, the largest trapped cobble had a critical shear stress of 218 N m-2, which is similar to shear stresses previously determined in the cave. Tracer rocks have been monitored twice with different sets of rocks. The mobilized tracer grains in the first experiment had a median grain size of 74mm with a maximum b axis length of 268mm. The median grain size is comparable to the 77mm median grain size obtained from Wolman counts in the affected reaches prior to the floods. The d84 grain size is being used for a second tracer rock study, but recent floods have been too small to move significant amounts of sediment. Nonetheless, floodwater velocities observed to date are between 1.5 and 1.7 m s-1 in the study reach for moderate floods and velocities during floods that moved a few rocks had maximum velocities of 0.77 and 2.1 m s-1. The critical shear stress for the largest entrained tracer rock in the second experiment was 126 N m-2, which is substantially less than shear stresses of 278-628 N m-2 generated by moderate floods recorded by an earlier study with discharges of ~1.5 m3 s-1. The results indicate that the cave is capable of transporting larger grains than are currently found in the study reach, which is consistent with intermittent exposures (open full item for complete abstract)

Committee: Gregory Springer (Advisor); Daniel Che (Committee Member); Eung Seok Lee (Committee Member) Subjects: Geological; Geology; Geomorphology

Master of Science, Miami University, 2023, Geology and Environmental Earth Science

Fluvial terraces are vital to reconstructing past depositional dynamics within a watershed as well as determining flood and erosion risk. In the midwestern US, detailed mapping of terrace age is necessary to determine if deposition occurred during multiple distinct periods. In this study, changes to soil geochemistry over time were quantified from nine radiocarbon-dated soils spanning ~17,000 years and this relationship was used to infer soil age across a broad fluvial terrace. Regression models quantifying Fe/Ca, Zr/Ca, and Ti/Ca changes at multiple soil depths were created. Fe/Ca models returned R2 values between 0.69 and 0.97 with the lowest uncertainties compared to Zr/Ca and Ti/Ca models. Samples collected at 20-30 cm depth resulted in the highest correlation coefficient compared to samples collected at 0-10 and 60-70 cm. The mean Fe/Ca value of parent material was 0.33 with standard deviation 0.12. The models were subsequently used to infer soil age from Fe/Ca values of 388 locations on the floodplain and overbank deposits were delineated based on inferred soil age. In general, deposit age increases with increasing distance from the modern channel. Results support use of this field-based technique to map fluvial terraces at a high resolution.

Committee: Jason Rech Dr. (Advisor); Maija Sipola Dr. (Committee Member); Claire McLeod Dr. (Committee Member) Subjects: Earth; Geology; Geomorphology; Soil Sciences

Master of Science (MS), Ohio University, 2023, Environmental Studies (Voinovich)

Agricultural nutrient pollution is a significant cause of impairment in American surface waters. Wetland restoration projects in agricultural watersheds can provide an effective sink for excess nutrients and potentially improve downstream water quality. Ohio University has partnered with The Stream and Wetlands Foundation to conduct water quality monitoring during the restoration of Bloody Run Swamp, a wetland in a former agricultural field near Columbus, Ohio. This thesis serves as an analysis of the initial water quality impacts of this restoration project. The restoration of Bloody Run Swamp did not significantly impact total dissolved phosphorus, orthophosphate, TKN, or ammonia concentrations. In contrast, both nitrate/nitrate and total dissolved nitrogen concentration and loads were significantly reduced during construction. This may have been due to the dry weather during construction and the removal of drainage tiles from Bloody Run Swamp. Future water quality monitoring is needed to determine the long-term impacts of this restoration project.

Committee: Natalie Kruse Daniels (Advisor); Gregory Springer (Committee Member); Morgan Vis (Committee Member) Subjects: Agriculture; Aquatic Sciences; Biology; Earth; Ecology; Environmental Engineering; Environmental Management; Environmental Science; Environmental Studies; Geomorphology; Hydrologic Sciences; Hydrology; Limnology; Water Resource Management

Master of Science, University of Toledo, 2023, Geology

Glacial Lake Agassiz is a paleolake that formed over central North America at the end of the last Ice Age at ~14.3 ka, and its drainage into the North Atlantic likely contributed to the Younger Dryas cooling at ~12,900–11,700 cal yr BP. Drainage events are identified through the chronologic and geomorphic analyses of strandlines, including beach ridges, escarpments, and spits, which record past lake levels. Strandlines in a study area in the southern basin of Lake Agassiz in NW Minnesota warp upward toward the north as a result of glacioisostatic adjustment (GIA). Older strandlines have a steeper north-south gradient than younger strandlines due to differential rates of rebound. The study area contains a series of strandlines that are classified into 11 strandline groups (SGs) rather than named beach ridges previously identified along other sections of the Lake Agassiz coastline. SGs are composed of one or two well-developed beach ridges, or sets of ridges, that branch out and increase in number toward the south, representing many minor drops in lake level up to ~3 m due to a combination of incision of the southern outlet and uplift caused by GIA. A beach ridge formation model developed from littoral sediment sample analyses and GPR data at 100–500 MHz frequencies suggest that strandlines in the study area formed in an overall depositional regressive system with intermittent storm events. The estimated beach ridge rate of formation is ~8.5-17 yrs/ridge based on ~70 Lockhart Phase beach ridges in the study area and the corresponding optically stimulated luminescence (OSL) dates for the Herman through Tintah beaches and meltwater signatures during drainage events. Strandline chronology is also assessed based on eight OSL dating samples. Most of the dates fell within the error margin for published dates from associated strandlines at the southern outlet. However, samples from the Campbell and Tintah beaches are approximately 3,000 years older t (open full item for complete abstract)

Committee: Timothy Fisher (Committee Chair); Richard Becker (Committee Member); Harry Jol (Committee Member) Subjects: Geology; Geomorphology

Master of Science (MS), Ohio University, 2023, Geological Sciences (Arts and Sciences)

Each cave is unique from structural or hydrological perspectives, which often complicates the prediction of subsurface flow routes needed for planning the economic development of karst landscapes and responding to groundwater contamination. This is true of the Great Savannah Cave System (GSCS) in southeastern West Virginia since the growing city of Lewisburg is expanding northward over the 50-mile-long cave system. The GSCS is the sixth-longest cave in the United States and pollution is affecting the cave in many still poorly defined ways. We report findings of a geological study of critical passages in GSCS as these findings to relate to subsurface flow paths and the prediction of unknown pathways. McClung Cave is in Greenbrier County in which the primary lithology is a Mississippian-age formation containing limestone and minor shales with negligible amounts of sandstone. Karst features of the GSCS formed along the contact zone between the Greenbrier and an underlying shale where streams sink upon encountering the limestones. Dip- and strike-oriented flow routes are analyzed using structural contouring, structural mapping, and passage morphologies. Vadose infeeders are generally oriented downdip, but with significant variability and hard-to-predict meandering due to geological features too small to be resolved in general geological mapping. Strike-oriented collector passages receive vadose streams from updip but are epiphreatic with infrequent filling during low recurrence interval floods. However, geological structures are only one control on the GSCS, and we present analyses of the host bedrock, including the qualitative results of thin-section studies designed to understand stratigraphic perching and selective cave development in certain lithologies. The information gained can be used to make predictions about flow routes and master conduits that have yet to be observed once additional data is collected.

Committee: Gregory Springer Dr (Advisor); Eung Seok Lee Dr. (Committee Member); Keith Milam Dr. (Committee Member) Subjects: Environmental Science; Geological; Geology; Geomorphology

Master of Science (MS), Ohio University, 2023, Geography (Arts and Sciences)

In current maps and geospatial datasets, representations of landforms such as mountains, hills, and ridgelines are unable to be drawn to their full extent. Due to the lack of a clearly observable boundary, the visualizations of these features are often limited to a singular point or line feature. This representation does not allow for an understanding of the true extent of landforms or the potential hierarchies that exist within the landscape. While manual attempts to delineate the extents of such features is always possible, it cannot be scaled for large areas with tens of thousands of features. In any case, there is no prescriptive way to delimit landforms, so no single set of delineated features can be considered sufficient for all people and contexts. In addition, the delineation of landforms depends on what type of landform is being searched for and the scale of delineation. Thus, this is not a deterministic process and needs to be context dependent. There needs to be flexibility and the focus should be on customizable methods, rather than canonical representations of landforms. The author of this thesis builds upon previous work within the field of geomorphometry and semi-automated feature extraction approaches by exploring and testing the applicability of several methods for delineating landforms within a range of study areas. The goal is to assess which methods produce linear (ridges) and non-linear eminences (peaks, summits, mountains) that match common sense expectations for what these features should look like in the real world, and by extension on maps. The six methods explored within this research were proposed by Wood (1996), Jasiewicz and Stepinski (2013), Lundblad et al. (2006), Chaudry and Mackaness (2008), Sinha (2008), and Miliaresis and Argialas (1999). The methods were selected based on their popularity within the research community and/or the author's judgment of the potential of the method for providing accurate mappings of terrain features (open full item for complete abstract)

Committee: Gaurav Sinha (Advisor); Timothy Anderson (Committee Member); Dorothy Sack (Committee Member) Subjects: Geographic Information Science; Geography; Geomorphology

Master of Science (MS), Ohio University, 2022, Geography (Arts and Sciences)

The need for understanding the impacts of off-road vehicle (ORV) usage on trail systems is widely accepted, with few studies being conducted in humid climates and even fewer examining the impacts of unauthorized user-created ORV routes. This research examines cross-trail profile measurements along authorized ORV trails and unauthorized ORV routes in southeastern Ohio over a six-month period in order to calculate erosion rates and understand how each trail type behaves throughout the riding season. Measurements from the two trail types are compared to one another in varying combinations and between data collection periods. Spatial comparisons of soil compaction and soil texture are also analyzed. Results from statistical analyses showed that there is no significant difference in erosion rates between authorized and unauthorized trail segments despite apparent differences in eroded sediments between the two trail types. The highest measured erosion rates on authorized and unauthorized segments totaled 3.65 m3/yr and 15.95 m3/yr, respectively. Few sites were found to have significant geomorphic change along the trail surface during the six-month study period. Soil compaction values were found to be greater on the trail surface compared to the trail-adjacent forest in both trail types. Soil compaction of the trail surface was not found to be statistically different between the two trail types, nor were values from the trail-adjacent forest different between the trail types. The results of this study demonstrate the need for effective management efforts that focus management efforts not only on authorized ORV trails, but also the unauthorized routes that are associated in ORV trail systems.

Committee: Dorothy Sack (Advisor) Subjects: Environmental Geology; Environmental Management; Geography; Geomorphology

Master of Science, Miami University, 2022, Geology and Environmental Earth Science

Stream restoration is a method used to try to return function to impaired streams and has become a billion-dollar industry in the U.S. A key limitation to stream restoration success, however, is an insufficient understanding of what streams in the Midwest were like prior to European settlement. By combining historical maps and aerial imagery with surficial geologic mapping; past stream channel pattern, controls on channel pattern, channel migration zones, and changes in fine sediment loads were identified for Four Mile Creek in southwestern Ohio. Gravel-bed, laterally active anabranching or meandering streams were dominant prior to European settlement. Wetland deposits, which are associated with some types of anabranching streams, were not prevalent in the mapping area during pre- or post-European settlement time periods. Channel migration rates appear to have declined by around 50% since the early 1800s and the percentage of mud in stream channels significantly increased after European settlement (p=0.010). This study and the associated map provide a baseline understanding of what the natural stream channel pattern and fine sediment loads were in the Midwest prior to anthropogenic disturbances in order to help inform stream restoration project designs.

Committee: Jason Rech (Advisor); Bartosz Grudzinski (Committee Member); Jonathan Levy (Committee Member) Subjects: Civil Engineering; Environmental Engineering; Geography; Geology; Geomorphology

Master of Science, The Ohio State University, 2022, Environment and Natural Resources

Unmanned aerial vehicles (UAVs) have an increasingly relevant role in the field of hydrology and water resources management. Their affordability and ease of use in comparison to traditional field-based methods have made research on their applications increase rapidly in the past decade. One application of UAVs to the hydrology of river systems is the estimation of particle sizes within a channel. This project investigated the ability of UAV imagery and Structure-from-Motion (SfM) photogrammetry to estimate grain-size distributions within a reach along the Olentangy River. To do this, we selected a study reach within the Highbanks Metro Park that was approximately 250 m in length and 50 m in width. We flew a DJI Mavic 2 Pro quadcopter UAV and collected imagery of subaerially exposed grains throughout gravels bars within this study reach. These images were processed using a SfM workflow that yielded point clouds and orthomosaics from which we extracted multiple topography-based and image-based metrics to be used as proxies for grain sizes. We then calibrated statistical regression models to predict the D50 and D84 grain size percentiles from these grain size proxies. While previous literature has suggested that topographic roughness metrics outperform image textural metrics for statistical grain size estimation, our study showed that the statistical models that were calibrated based on image textural properties performed better than those that were calibrated based on point cloud roughness properties. This contradiction may reflect the unique nature of our study site where the grains were dominated by smaller particles in comparison to other studies. The smaller grain sizes in our study area would have likely produced less significant topographic signatures in comparison to larger grains, which makes topographic roughness difficult to accurately measure and apply to statistical grain size estimation techniques. The results of this study suggest that topography-based g (open full item for complete abstract)

Committee: Steve Lyon (Advisor); Sami Khanal (Committee Member); Kaiguang Zhao (Committee Member) Subjects: Environmental Science; Geology; Geomorphology; Hydrologic Sciences; Hydrology; Water Resource Management

Master of Arts, The Ohio State University, 2022, Geography

Improving tropical glacier modeling capacity is crucial for deriving climatological insight from tropical glacier fluctuations on historical to multi-millennial timescales and for predicting socially relevant glacier environmental changes under anthropogenic climate warming. Using the glacierized Queshque Valley of Peru's Cordillera Blanca as a case study, this thesis first develops data assimilation and calibration methods to adapt a coupled temperature-index mass balance and glacier flow model to tropical settings. The calibrated model is applied to project glacier evolution in the valley under an ensemble of climate change scenarios, confirming the high probability of near complete deglaciation by the end of this century. Despite the glacier's current trajectory, moraine features signal that ice once extended about 6km further down valley. Three cosmogenic nuclide dated moraines reveal extended ice cover at 10.8ka, 9.4ka, and 6.2ka BP, and historical maps show that the glaciers have retreated considerably since 1962 CE. Equilibrium experiments are used to identify all possible climatic conditions producing stable glaciers at the positions marked by the moraines and historical ice limit. Relative to the 1985-2015 CE climatic baseline, results suggest that valley temperatures were 2.9-1.9˚C cooler at 10.8ka BP and at least 1.0˚C cooler at 9.4ka BP. Proximity between the 9.6ka and 6.2ka moraines makes their climatic signatures difficult to distinguish. Finally, the equilibrium experiment confirms that in 1962 the glacier was already far out of balance. In summary, this thesis presents a data-intensive approach to improving model performance on a tropical glacier, enabling accurate ice loss projections, and helping to constrain paleoclimatic interpretations of tropical glacier geomorphology.

Committee: Bryan Mark (Advisor); Zhengyu Liu (Committee Member); Ellen Mosley-Thompson (Committee Member) Subjects: Geography; Geomorphology

Master of Arts, University of Toledo, 2021, Geography

On February 15th, 2019, Indiana Dunes was elevated to the designation of a U.S. National Park. Along with this designation belongs the credo of the U.S. National Park Service, to conserve such places that are deem naturally, historically, or in so many words ecologically important by such means as will leave them unimpaired for the enjoyment of future generations. In 2019, the water level in Lake Michigan was trending above the long term recorded average, and as a result several locations in the National Park sustained damage due to erosion and inundation. Current water levels are receding, but predictions suggest that fluctuations from low to high periods will becomes more frequent and more severe. Acknowledging that this may be a certain outcome, requires a great understanding of the shoreline morphology within the National Park, especially considering such namesake features as the shoreline dunes. This study uses LiDAR data from an era of below average to a period of elevated water level for five areas of interest within Indiana Dunes National Park, to categorize levels of change in the near shore and beach regions, as well as quantify metrics of beach width change. Resulting in several Areas of Interest containing mixed values of dune elevation loss with some gain. Importantly identifying that Mount Baldy and Central Avenue Beach have majorly experienced dune elevation loss where iv gains were not seen based on dune migration. Additional findings include the massive inundation of beach area and substantial loss of foredunes at Portage Beach and the token area of Beach width gain at Beverly Shores (East).

Committee: Patrick Lawrence (Committee Chair); Kevin Czajkowski (Committee Member); Ricky Becker (Committee Member) Subjects: Geography; Geomorphology; Remote Sensing

PhD, University of Cincinnati, 2021, Arts and Sciences: Geology

How do karst landscapes evolve over thousands to millions of years? How do various erosional processes contribute to that evolution? These are persistent questions in geomorphology and speleology. This dissertation addresses the question of processes from an erosion, transport, and deposition perspective. First, I cover the numerical modeling of abrasional wear by sediment transport in a cave passage, proposing a set of erosional zones comparing the contributions from dissolution and abrasion to the enlargement of cave passages. I then discuss the initiation of a long-term micro-erosion monitoring study in a cave river in Mammoth Cave National Park. It is anticipated that decades from now, data from that project will provide additional evidence to validate or refute the numerical modeling results. Next, I share the fieldwork investigation results of a sediment deposit in a different portion of Mammoth Cave. This was determined to be a debris flow deposit and a timeline of events leading to its deposition was proposed. Finally, I present the curricula of two activities designed to present karst hydrology and geomorphology to a wide variety of learners. These were then incorporated into Virtual Capstone Pathways to provide accessible and inclusive online options for undergraduate students. Deeply understanding our landscapes and their processes, and communicating about that knowledge effectively and accessibly can help people be passionate stewards of the land and of knowledge.

Committee: Dylan Ward Ph.D. (Committee Chair); Shaaban Abdallah Ph.D. (Committee Member); Matthew Covington Ph.D. (Committee Member); Craig Dietsch Ph.D. (Committee Member); Mohamad Reza Soltanian Pereshkafti (Committee Member) Subjects: Geomorphology

Master of Arts, Miami University, 2021, Geography

Previous research has indicated that agricultural land-use often reduces water quality in streams. This includes: 1) an increase in total suspended solids (TSS) due to elevated soil erosion and 2) changes in dissolved organic carbon (DOC) concentrations. The goal of this study is to determine if a forested state park can mitigate these potentially negative impacts. This study examines spatial and temporal dynamics of TSS and DOC in four streams, located in an agriculturally impacted watershed in SW Ohio, as they flow from agricultural land-cover through a naturally forested state park. Eight surface water sites were sampled bimonthly over a one-year period from December 2019 to December 2020. Each water sample was processed to quantify concentrations of TSS and DOC. In addition to examining the impact of land use, this study also examined the effect of discharge and the normalized difference vegetation index (NDVI) on changes to TSS and DOC concentrations. A significant increase in TSS concentrations was found within the state park. The changes in TSS concentrations were not significantly related to stream discharge nor NDVI. A significant decrease in DOC concentrations was found in two streams within the state park. Discharge was negatively correlated with changes in DOC concentrations in three of four streams. The results suggest that small streams in the U.S. Midwest are able to reduce fluvial DOC concentrations in agricultural watersheds within naturally forested areas. Further research is needed to determine why TSS concentrations increased within the forested state park.

Committee: Bartosz Grudzinski (Advisor); Jessica McCarty (Committee Member); Fadel Megahed (Committee Member); Michael Vanni (Committee Member) Subjects: Geography; Geomorphology; Hydrology

MS, Kent State University, 2021, College of Arts and Sciences / Department of Earth Sciences

Glacial Lake Maumee (an early ancestor to Lake Erie) developed extensive beach ridges and bars that included an elongate arcuate bar complex at Columbus Grove, OH, that was very similar to the modern Presque Isle flying spit at Erie, PA, in terms of shape, its 10 km length, its shoreline orientation, and its angle from the coast, although it is extremely narrow, distally discontinuous, and extremely thin. The bars consist of relatively fine-grained, poorly sorted, polymodal sediment that has been extensively bioturbated and plowed, although their shapes are well preserved on the modern surface and they retain useful grain size signals regarding depositional processes and settings. Lake floor sediments are primarily very fine to medium silts with secondary clays and minor sands. Bars appear to have accreted in place, locally with lateral expansion but without significant migration or erosion. Vertical successions vary from cryptic upward shoaling and coarsening to quite heterogenous (better seen by extracting peaks rather than using basic descriptive statistics). Bars are thin (commonly <.5 - 1 m), and at least some begin with a marked shift from lake-floor silt to relatively well-developed sands, although rarely as coarse as sand peaks higher in the core. This suggests initiation by extreme waves touching bottom in relatively deep places, and thereby beginning construction of a sand pile that can benefit from progressively weaker waves as it grows upward. The arcuate shape of the bar complex is attributed to waves shoaling against an accretionary bulge in the coastline. However, until the bars start to connect and become continuous, longshore drift is not developed and lateral transport is prohibited, so bar segments grow individually from locally scavenged sand. This lake phase is thought to have been too short-lived to have permitted the bar to mature into a spit and become wide and complicated.

Committee: Neil Wells Dr. (Advisor); Joseph Ortiz Dr. (Committee Member); Anne Jefferson Dr. (Committee Member) Subjects: Geological; Geology; Geomorphology

Master of Science (MS), Ohio University, 2021, Environmental Studies (Voinovich)

Flood analyses have historically been conducted using the stationarity principle, which assumes a constant hydrological regime within a river system. This research echoed previous studies challenging the assumption of stationarity for the purposes of flood analyses. The Greenbrier River watershed in West Virginia fit criteria for questioning the stationarity principle as it experienced dramatic forest harvesting activities in the late 1800s and has suffered deadly floods in the last four decades. This research questioned the stationarity assumption by testing hydrological data using Pearson's and Pettitt's tests. Additionally, two scenarios were developed to spatially model runoff travel time for a forested and deforested watershed. Stationarity was confirmed for the Greenbrier River. The study showed no evidence of non-stationarity in the hydrological time series of the river, despite widespread changes in land use across the study period. Similarly, spatial modeling of total runoff travel time estimation between watershed scenarios did not drastically vary.

Committee: Gregory Springer Dr. (Committee Chair); Natalie Kruse Dr. (Committee Member); Jenny Schenk Dr. (Committee Member) Subjects: Environmental Studies; Geographic Information Science; Geomorphology; Hydrology

Master of Science, The Ohio State University, 2021, Earth Sciences

Log jams are natural features in mountain streams that promote stream-groundwater interactions, or hyporheic exchange, through a variety of mechanisms. Log jams alter gradients in hydraulic head, increase the area available for exchange by creating backwater areas, and lead to the formation of branching channels and bars that drive additional exchange. Here, I numerically simulated stream-groundwater interactions for two constructed flume systems—one without jams and one with a series of three jams—to understand the effects of interacting jam and channel structures on hyporheic exchange. Jams increased stream-groundwater connectivity, or decreased the turnover length that stream water travels before it enters the hyporheic zone, by an order of magnitude and drove long flow paths that connected multiple jams and channel threads. The increased turnover of stream water through the bed was due mainly to the increase in the average hyporheic exchange rate, though the wetted surface area available for exchange also increased slightly. Jams with larger volumes had longer hyporheic residence times and path lengths that exhibited multiple scales of exchange. Additionally, the longest flow paths connecting multiple jams occurred in the reach with multiple channel branches. These findings suggest that large gains in hydrologic connectivity can be achieved by promoting in-stream wood accumulation and the natural formation of both jams and branching channels.

Committee: Audrey Sawyer (Advisor); Michael Durand (Committee Member); Joachim Moortgat (Committee Member) Subjects: Geomorphology; Hydrologic Sciences; Hydrology

Master of Science, The Ohio State University, 2021, Earth Sciences

The Chandeleur Slide is a large submarine landslide on the Gulf of Mexico seafloor in approximately 1100 meters of water, 200 km southeast of New Orleans, LA. This part of the Mississippi Fan received high sedimentation throughout the Pleistocene, causing high pore fluid pressure and abundant slope failures, though few as large as the Chandeleur. Given its proximity to major coastal cities, oil and gas infrastructure, and its large size, I examine the Chandeleur Slide to: (1) map the location and thickness of the displaced sediment, (2) understand what led to the initial slope failure, (3) decipher if this was a fast-moving or slow-moving event, and (4) consider potential hazard implications a slide like the Chandeleur represents for seafloor infrastructures and tsunami risks to coastal communities surrounding the Gulf of Mexico. I interpreted publicly available 2D and 3D multichannel seismic surveys and high-resolution bathymetry data to reveal several flow paths generally due south/southeast, and a slow-moving sediment mass with a translational-rotational behavior. The Chandeleur Slide includes extensional faulting in the headscarp area and compressional structures in the northern-most toe confined by a natural ramp-like structure. Beneath the Chandeleur Slide, I observe an upward-migrating salt body that has compressed a regional sand-rich unit (the Blue Unit). I interpret that the upward-migrating salt led to overpressure within Blue Unit sand layers, facilitating the initial failure of the Chandeleur. After failure, the Chandeleur Slide transported a large volume of sediment southward but was blocked by antecedent topographic highs that deflected much of the sediment to the south/southwest. The initial failure was followed by retrogressive headwall retreat northward, which created the prominent scarp on the seafloor. In total, the Chandeleur Slide comprises an area just over 1000 km2 and contains about 300 km3 of failed sediment.

Committee: Derek Sawyer Dr. (Advisor); Ann Cook Dr. (Committee Member); Daniel Pradel Dr. (Committee Member) Subjects: Earth; Environmental Geology; Geographic Information Science; Geological; Geology; Geomorphology; Geophysics; Geotechnology; Marine Geology

Master of Science (MS), Ohio University, 2021, Geological Sciences (Arts and Sciences)

Scallops are concave dissolution features that can form on soluble surfaces. These features have been used to recreate paleoflow conditions within cave systems. The goal of this study was to expand the knowledge of scallop spatial distributions and related statistics. We tested scallops' spatial distributions against random Poisson distributions. In order to test this, we measured scallops from Buckeye Creek Cave and the Boarhole Portal Cave System in Greenbrier, West Virginia and we performed statistical analyses on those measurements. We looked at the variance in scallop lengths between the two caves to determine if the distributions were statistically similar and concluded they were not. We then compared the variances of scallops on a vertical transect to those on a horizontal transect and found that this was inconclusive depending on passage geometry. Scallop distributions were compared to a random Poisson distribution and it was found that both cave's scallop distributions follow a random Poisson distribution, but are weakly inhibited. This was then corroborated by nearest neighbor analysis of scallops showing normality of the nearest neighbor distances, implying random relationships. Together, these results expand on reconstructing paleoflow with the of the spatial distribution of scallops. However, more work is needed to further understand the significance cave geometry contributes to reconstruction with scallop distribution.

Committee: Gregory Springer (Advisor); Katherine Fornash (Committee Member); Eung Seok Lee (Committee Member) Subjects: Geological; Geology; Geomorphology; Hydrology