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Contribution of Hurricane Ike Storm Surge Sedimentation to Long-term Aggradation of Coastal Marshes in Southeastern Texas and Southwestern Louisiana

Description: Coastal marshes and wetlands are vital natural resources that offer habitats for plants and animals, serve as ecological filtration for soil and water pollutants, and act as protection for coastlines. Fishing, both commercial and sport, has a large economic impact in the study area – the Gulf Coast between Galveston Bay, TX and Oak Grove, LA. The objective of this research was to determine the contribution of Hurricane Ike storm surge sedimentation to long-term marsh aggradation in Texas and Louisiana coastal marshes. The research hypothesized that Hurricane Ike’s storm surge deposit would be equal to decades and possibly even a century’s worth of the average annual non-storm sedimentation. A quantitative field study was performed. The storm surge deposit was examined in a series of 15 transects covering approximately 180 km east of Hurricane Ike’s landfall. Nine of the 15 transects were re-surveyed a year after the initial measurement to assess preservation of the deposit. The results demonstrate that Hurricane Ike contributed between 10 to 135 years’ worth of sediment to coastal marshes along the coasts of Texas and Louisiana, and the sediment deposits have been preserved for over two years.
Date: August 2013
Creator: Denlinger, Emily E.

County Level Population Estimation Using Knowledge-Based Image Classification and Regression Models

Description: This paper presents methods and results of county-level population estimation using Landsat Thematic Mapper (TM) images of Denton County and Collin County in Texas. Landsat TM images acquired in March 2000 were classified into residential and non-residential classes using maximum likelihood classification and knowledge-based classification methods. Accuracy assessment results from the classified image produced using knowledge-based classification and traditional supervised classification (maximum likelihood classification) methods suggest that knowledge-based classification is more effective than traditional supervised classification methods. Furthermore, using randomly selected samples of census block groups, ordinary least squares (OLS) and geographically weighted regression (GWR) models were created for total population estimation. The overall accuracy of the models is over 96% at the county level. The results also suggest that underestimation normally occurs in block groups with high population density, whereas overestimation occurs in block groups with low population density.
Date: August 2010
Creator: Nepali, Anjeev

Decoding the Formation of a Retail Giant: the Evolving Geography of Costco’s Store Network

Description: Although Costco operates over 580 warehouse stores throughout North America, their location strategy remains relatively unexamined in the economic geography literature. A cursory examination of Costco’s network makes it clear that the firm chooses to locate primarily in the suburbs of major cities, where income levels are somewhat higher than the national average. However, what is not clear is the extent to which other demographic and geographic factors adequately account for Costco’s store locations, and what strategy underlies the geography of the firm’s warehouse stores, especially in relation to its distribution network. This research studies Costco in order to decode the location strategies that have guided the company’s North American and international expansions. The investigation attempts to identify key elements of Costco’s multinational retail network, including this network’s evolution over time. This paper seeks to benefit both retail business and public policymakers by highlighting elements of Costco’s location strategy that have contributed to the firm’s success.
Date: December 2015
Creator: Testa, Peter

The Descriptive Paleontology and Applied Ichthyoarchaeology of the Ponsipa Fauna

Description: The archaeology of the Northern Rio Grande region of New Mexico has recently received an increased amount scholarly attention. In particular, understanding past trends in demographics, agricultural productivity, violence, and social networks have been primary goals of archaeological research. Understanding patterns in animal exploitation has, however, received far less attention due to a small yet growing regional zooarchaeological database. Through the identification of animal remains from a site called Ponsipa (occupied ca. A.D. 1300 to 1600), this thesis adds one large dataset to this growing database. In addition, this thesis expands on the pre-impoundment distribution of an endangered native freshwater fish species in the state of New Mexico called the blue sucker (Cycleptus elongatus). The blue sucker is a unique fish that is currently experiencing range reduction across all of its known North American distribution due to anthropogenic habitat fragmentation and degradation. Skeletal remains that were identified from Ponsipa represent the farthest known northern record of its occurrence in the state of New Mexico and highlight the extent of range restriction of the species in the area. The data concerning the historical biogeography of the blue sucker from Ponsipa have implications for the effective conservation and restoration of blue sucker located in the Rio Grande Basin.
Date: May 2015
Creator: Dombrosky, Jonathan

Dismantling the Psychiatric Ghetto: Evaluating a Blended-Clinic Approach to Supportive Housing in Houston, Texas

Description: Locational decisions based on stigma and low funding have handicapped the efficiency of community based mental healthcare in the United States since 1963. However, the pattern of services in the 21st century American South remains largely unknown. This thesis addresses this gap in knowledge by using a mixed methodology including location allocation, descriptive statistics, and qualitative site visits to explore the geography of community clinics offering both physical and mental health services. The City of Houston has proposed using these facilities to anchor new supportive housing, but introducing more fixed costs to a mismatched system could create more problems than solutions. The findings of this study suggest the presence of an unnecessary concentration of services in the central city and a spatial mismatch between accessible clinics and the poor, sick people in need. Furthermore, this research reveals a new suburban pattern of vulnerability, calling into question long-held assumptions about the vulnerability of the inner city. Building supportive housing around existing community clinics, especially in the central city, may further concentrate vulnerable people thereby contributing to intensifying patterns of service-seeking drift and the continued traumatization of mentally ill homeless persons in Houston.
Date: December 2014
Creator: Lester, Katherine Ann

Effects of Non-homogeneous Population Distribution on Smoothed Maps Produced Using Kernel Density Estimation Methods

Description: Understanding spatial perspectives on the spread and incidence of a disease is invaluable for public health planning and intervention. Choropleth maps are commonly used to provide an abstraction of disease risk across geographic space. These maps are derived from aggregated population counts that are known to be affected by the small numbers problem. Kernel density estimation methods account for this problem by producing risk estimates that are based on aggregations of approximately equal population sizes. However, the process of aggregation often combines data from areas with non-uniform spatial and population characteristics. This thesis presents a new method to aggregate space in ways that are sensitive to their underlying risk factors. Such maps will enable better public health practice and intervention by enhancing our ability to understand the spatial processes that result in disparate health outcomes.
Date: December 2014
Creator: Jones, Jesse Jack

Effects of Vegetation Structure and Canopy Exposure on Small-scale Variation in Atmospheric Deposition Inputs to a Mixed Conifer Forest in California

Description: Data on rates of atmospheric deposition is limited in many montane ecosystems, where high spatial variability in meteorological, topographic, and vegetation factors contributes to elevated atmospheric inputs and to the creation of deposition hotspots. Addressing the ecological consequences of increasing deposition in these areas will require a better understanding of surface controls influencing atmospheric deposition rates at both large and small-scales. The overarching objective of this thesis research was to understand the influence of vegetation structure and canopy exposure on small-scale patterns of atmospheric sulfate, nitrate, and chloride deposition inputs to a conifer forest in the Santa Cruz Mountains, California. Throughfall ion fluxes (i.e., ions delivered in water that pass from the forest canopy to the forest floor), bulk deposition (i.e., primarily wet deposition), and rainfall data were collected during the rainy period from October 2012 to May 2013. Throughfall SO42-, Cl-, and NO3- fluxes were measured beneath eight clusters of Douglas fir (Pseudotsuga menziesii) trees (three trees per cluster) differing in tree size (i.e., diameter at breast height; DBH) and canopy exposure. In each cluster, a throughfall collector was placed 1-meter from the bole of an individual tree, for a total of 24 individual collectors. The position of each throughfall collector was recorded with a Trimble® GPS. In addition, tree height, tree diameter, and leaf area index, were measured for all trees. LiDAR data were obtained from GeoEarthScope’s Northern California Airborne LiDAR project and used to model the elevation (DEM), canopy surface height (DSM), tree height (CHM), slope, and curvature of the canopy surface across the entire study area. Over the rainy season, total throughfall flux of SO42--S, a conservative tracer of total deposition (wet + dry + fog), to Douglas fir clusters ranged from 1.44 - 3.84 kg S ha-1 wet season-1, while dry and fog deposition ranged ...
Date: May 2014
Creator: Griffith, Kereen

Efficiency of Nitrate and Phosphorus Removal in a Working Rain Garden

Description: Rain gardens are low impact developments designed to mitigate a suite of issues associated with urban stormwater runoff. The site for this study was a Denton City rain garden at the Denton Waste Water Treatment Plant. Nitrogen and phosphorus removal was examined in light of two overflow events comprised of partially treated wastewater from an upslope anaerobic digester pond. Nitrate removal efficiency was examined across differing dry spell intervals of 5, 8, and 12 d, displaying a moderate negative correlation (r2 = 0.59). Continued phosphorus removal capacity was assessed, showing phosphorus removal in cases where P was in excess of 0.8 mg/L, reflecting an equilibrium phosphorus concentration. A high expanded shale component in the soil media (25%) was likely a factor in the continued removal of phosphorus. Overall the rain garden proved to be a large source of nitrate (+425%) and total nitrogen (+61%) by mass. The study showed that while the rain garden intercepted a large volume of partially treated wastewater during the overflow events, preventing it from reaching a nearby creek, the mitigation of an acute event has extended to a chronic one as nitrogen is gradually processed and flushed from the system as nitrate.
Date: August 2015
Creator: Strong, Patrick

Emergency Fire Response in Ghana: The Case of Fire Stations in Kumasi

Description: Comprehensive emergency management and response is crucial for disaster prevention and health emergencies. However, in African countries with an abundance of natural disasters and a rising surge in cardiovascular and obstetric emergencies, little research exists on emergency response. This study examines the fire emergency response in Kumasi Metropolitan Assembly (KMA), Ghana's second largest city. We use Geographic Information Systems (GIS) tools including location -allocation modeling to evaluate the existing system of fire facilities, identify gaps in service, and suggest locations for new fire stations to maximize population coverage. Our results show that fire stations within KMA are poorly distributed and large portions of the metropolis are underserved, a situation that is partly responsible for the huge losses of lives and property during fire outbreaks.
Date: May 2017
Creator: Boakye, Kwadwo Adu

Examining the Role of Latitude and Differential Insolation in Asymmetrical Valley Development

Description: Valley development through erosional processes typically tends to create symmetrical valleys. Over time, water cuts through the substrate to create valleys, gorges, and canyons for which the sides are the valley are evenly sloped. However, there are anomalies to this process. Asymmetrical valleys have been well-documented even in areas of uniform substrate or little tectonic uplift. One proposed explanation for the asymmetry of these valleys is differential insolation. This may lead to different microclimates from one slope to another which alter the rate and extent of erosion. Since the differences in received insolation vary with latitude (especially in streams that flow along an east/west axis), it follows that the degree of asymmetry should also vary with latitude if differential insolation is a primary driving factor in the development of these valleys. To evaluate if insolation plays a role in the development of asymmetrical valleys, this study examines variability in asymmetry across 447 valleys in nine study areas located at different latitudes. The degree of asymmetry for each valley was measured by using 30 meter resolution digital elevation models (DEMs) to determine the slope angle of each side of the valley. Asymmetry was measured by computing a ratio of the average slope angle for each side of the valley (larger value divided by smaller). If the resulting value is one, the valley is deemed symmetrical. As the value increases, the degree of asymmetry increases. This investigation found that contrary to expectations, valleys at lower latitudes tend to have a higher degree of asymmetry than those at higher latitudes, which suggests that differential insolation does not play a major role in the development of these valleys. Instead, this study found that high altitudes and low latitudes are more frequently associated with a higher degree of asymmetry. These unexpected findings open the door ...
Date: August 2013
Creator: Curran, Lorna L.

Exceedance Frequency Analysis of Urban Stormwater Quality and Its Relation to Land Use Change, Denton, Texas

Description: Urbanization causes various environmental issues including water pollution, air pollution, and solid waste. Urbanization of watersheds has a profound influence on the quality of stormwater runoff. The quality of stormwater runoff is highly associated with land use. This study analyzed the exceedance frequency of stormwater quality in five watersheds of Denton over eleven years and also analyzed the relationship between stormwater quality and land use/cover of each watershed. The results showed that the most of the water quality parameters that were examined in the Lower Pecan watershed exceeded their threshold most frequently. The higher frequency of exceedance in this watershed can be attributed to the wastewater treatment plant and landfill site. Total suspended solids and turbidity were frequently exceeded in Hickory and Clear Creek watersheds. Conductivity was found to have highest percentage of exceedance in Upper Pecan and Cooper watersheds. Thus, rural watersheds were related with higher exceedance of TSS and turbidity whereas urban watersheds were related with higher exceedance of conductivity.
Date: August 2015
Creator: Shrestha, Manjul

An Exploration of the Ground Water Quality of the Trinity Aquifer Using Multivariate Statistical Techniques

Description: The ground water quality of the Trinity Aquifer for wells sampled between 2000 and 2009 was examined using multivariate and spatial statistical techniques. A Kruskal-Wallis test revealed that all of the water quality parameters with the exception of nitrate vary with land use. A Spearman’s rho analysis illustrates that every water quality parameter with the exception of silica correlated with well depth. Factor analysis identified four factors contributable to hydrochemical processes, electrical conductivity, alkalinity, and the dissolution of parent rock material into the ground water. The cluster analysis generated seven clusters. A chi-squared analysis shows that Clusters 1, 2, 5, and 6 are reflective of the distribution of the entire dataset when looking specifically at land use categories. The nearest neighbor analysis revealed clustered, dispersed, and random patterns depending upon the entity being examined. The spatial autocorrelation technique used on the water quality parameters for the entire dataset identified that all of the parameters are random with the exception of pH which was found to be spatially clustered. The combination of the multivariate and spatial techniques together identified influences on the Trinity Aquifer including hydrochemical processes, agricultural activities, recharge, and land use. In addition, the techniques aided in identifying areas warranting future monitoring which are located in the western and southwestern parts of the aquifer.
Date: August 2011
Creator: Holland, Jennifer M.

Faunal Exploitation during the Depopulation of the Mesa Verde Region (A. D. 1300): A Case Study of Goodman Point Pueblo (5MT604)

Description: This analysis of faunal remains from Goodman Point Pueblo (5MT604), a large village occupied just before the ancestral Puebloans permanently left southwestern Colorado at the end of the thirteenth century, explores the effect of dietary stress during abandonment in the Four Corners region. As archaeologists, we interpret what these former cultures were like and what resources they used through what they left behind. By specifically looking at faunal remains, or remains from food resources, environmental change and dietary stress can be assessed. Identifications of taxa identified at Goodman Point are made explicit via a systematic paleontology. This is followed by site-level taxonomic abundances and spatial analysis. Then, effects of technological innovations, environmental change, and sample quality are examined as alternate explanations of shifts in foraging efficiency, particularly related to animal hunting. Analyzing why and if the availability of faunal resources changes over time helps to clarify why the ancestral Puebloans left southwestern Colorado.
Date: August 2011
Creator: Hoffman, Amy Susan

Finding Terroir in Southwest Iowa

Description: Terroir combines the physical landscape of the vineyard with the grapevines and the methods and techniques used to produce wine from the grapes. This study used a GIS to identify the characteristics of the physical landscape in Pottawattamie, Mills, Montgomery, Fremont, and Page counties in southwestern Iowa. The components were combined in the GIS using a weighted linear index to identify areas suitable for vineyard development and to identify the general characteristics of the area. Vineyard owners were interviewed to help determine the weighting system to use in the GIS and to determine their perceptions of how the physical landscape impacts their vineyards, as well as to determine what grape varieties they plant in their vineyards and their decisions on making wine from these grapes. This information was collected to identify whether the vineyard owners had developed a sense of place for their vineyards and how this sense might aid them in the development of a terroir for their wines. The resulting perceptions about the individual wineries were then considered in conjunction with the results from the GIS modeling to understand how the physical landscape influences the concepts of sense of place and terroir in southwest Iowa. The physical landscape of southwest Iowa was fairly uniform, as were the grape varietals planted in the vineyards. This created a measure of similarity among the wineries, while individuality between wineries was then created by the wine-makers as they used different techniques to produce wine from the grapes. This allows each winery to develop a sense of place, yet be part of a larger sense of place that encompasses multiple wineries within the area.
Date: August 2013
Creator: Deines, Dory

Gentrification in Oklahoma City: Examining Urban Revitalization in Middle America

Description: Gentrification applies not only to the largest and oldest cities; it is a multi-scalar phenomenon playing out in smaller and less prominent settings as well. This study examines temporal changes in property values, demographic characteristics, and types of businesses in the central Oklahoma City area. A major urban revitalization project which began in 1993 created strong gentrification characteristics near the renewal's epicenter, the Bricktown entertainment district. Data suggest that several specific neighborhoods in the surrounding area exhibited rising property values, improving educational attainment rates, decreasing household sizes, and a shift toward cosmopolitan retail activity. While it is evident that Bricktown has been transformed, the socio-economic traits of surrounding neighborhoods have been altered by the ripple effects of urban renewal.
Date: August 2011
Creator: Petty, Clint C.

Geoarchaeological Analysis of Two New Test Pits at the Dmanisi Site, Republic of Georgia

Description: This thesis presents the results of geoarchaeological investigations conducted at two new test pits, M11 and M12, at the paleoanthropological site of Dmanisi during the 2012 field season. This research is important for understanding the site formation processes occurring along the north-south axis of the Dmanisi site and how that affects the chronostratigraphic sequence and interpretation of archaeological materials here. With these excavations we can build a stronger interpretation for how broader areas of this site formed and changed both geologically and archaeologically. The geologic results of this study indicate that changes in sediment deposition and development episodes can affect interpretations of how long these sediments accumulated, how likely bones are to preserve, as well as how secondary gravel deposition can influence several archaeological interpretations. The archaeological results suggest that there could have been changes in occupation intensity between the stratum A and B phases although different rates of sediment deposition and surface stability could affect such artifact accumulations. In addition, during the stratum B phase there appears to be little change in artifact procurement behaviors and reduction characteristics by these hominins. The overall results of this research indicate that geologic factors should be addressed and cautions should be taken prior to making interpretations about archaeological assemblages.
Date: May 2013
Creator: Zack, Winston S.

A Geoarchaeological Investigation of Site Formation in the Animas River Valley at Aztec Ruins National Monument, NM

Description: This paper presents an investigation of sedimentary deposition, soil formation, and pedoturbation in the Animas River Valley to determine the provenience of archaeological deposits in an open field at Aztec Ruins National Monument, NM outside of the Greathouse complex. Four stratigraphic pedounits correlated with active fan deposition have been proposed for the lower terrace in the project area with only one of these units retaining strong potential for buried archaeological deposits from the Anasazi late Pueblo II/Pueblo III period. The distal fan on the lower terrace and the Animas River floodplain appear to show poor potential for archaeological deposits either due to shallow sediment overburden with historic disturbance or alluvial activity during or after occupation. Based on these findings, four other zones of similar fan development have been identified throughout the Animas Valley and are recommended for subsurface testing during future cultural resource investigations.
Date: August 2010
Creator: Caster, Joshua

Geography of HIV Infection Among Adults Aged 50 Years and Older in Texas From 1999-2009

Description: Twenty four percent of all HIV infections in the United States occur among adults aged 50 and older (mature adults), yet little is understood of the dynamics of HIV infection among this group in Texas. Data from 1999 to 2009 examined the relationship between HIV spatial and temporal patterns affecting socio-economic and demographic variables including poverty, gender, race/ethnicity and mode of exposure. Results revealed highest HIV infection rates among White homosexual men, Black males engaged in IV-drug use, Black female heterosexuals and minorities in poverty. Concentrations of HIV infection among mature adults were located primarily in urban centers of Houston and Dallas and indicated increasing HIV infection rates from 1999 to 2009. These results will assist future allocation of resources by zip code in urban areas for this understudied population.
Date: August 2012
Creator: Hedrich, Mara Nicole

The Geography of Maternal Health Indicators in Ghana

Description: Ghana is identified among the developing countries with high maternal mortality ratio in Africa. This study unpacked the Demographic and Health Survey data by examining the maternal health indicators at the district level using GIS methods. Understanding the geographic patterns of antenatal care, place of delivery, and skilled birth attendants at the small scale will help to formulate and plan for location-specific health interventions that can improve maternal health care behavior among Ghanaian women. Districts with high rates and low rates were identified. Place of residence, Gini-Coefficient, wealth status, internet access, and religious affiliation were used to explore the underlying factors associated with the observed patterns. Economic inequality was positively associated with increased use of maternal health care services. The ongoing free maternal health policy serves as a cushion effect for the economic inequality among the districts in the Northern areas. Home delivery is common among the rural districts and is more prominent mostly in the western part of Northern Region and southwest of Upper West. Educating women about the free maternal health policy remains the most viable strategy for positive maternal health outcomes and in reducing MMR in Ghana.
Date: May 2017
Creator: Iyanda, Ayodeji Emmanuel

The Geography of Maternal Mortality in Nigeria

Description: Maternal mortality is the leading cause of death among women in Nigeria, especially women aged between 15 and 19 years. This research examines the geography of maternal mortality in Nigeria and the role of cultural and religious practices, socio-economic inequalities, urbanization, access to pre and postnatal care in explaining the spatial pattern. State-level data on maternal mortality rates and predictor variables are presented. Access to healthcare, place of residence and religion explains over 74 percent of the spatial pattern of maternal mortality in Nigeria, especially in the predominantly Muslim region of northern Nigeria where poverty, early marriage and childbirth are at its highest, making them a more vulnerable population. Targeting vulnerable populations in policy-making procedures may be an important strategy for reducing maternal mortality, which would also be more successful if other socio-economic issues such as poverty, religious and health care issues are promptly addressed as well.
Date: May 2012
Creator: Ebeniro, Jane

Geologic and Lithic Analysis of the Red River Cache

Description: The Red River Cache is an assemblage of 33 bifaces, found in Cooke County, along Cache Creek, a tributary to the Red River. Also found with the cache was a hearth which yielded charcoal for AMS dating which returned an age of 2770- 2710 Cal YBP placing the cache in the Late Archaic. The geologic investigation of Cache Creek established 3 Holocene allostratigraphic units that provide information depositional environments adjacent to the Red River. Lithic analysis explored the production of bifaces during the Late Archaic and compared the cache to regional records. Using both geologic and lithic analysis this thesis investigates the temporal and cultural context of the cache using a geoarchaeological approach.
Date: May 2011
Creator: Gregory, Brittney

The Global Expansion of Transnational Retailers: A Case Study of the Localization Strategy of Costco in Taiwan

Description: This research focuses on the global expansion of the transnational retail industry. Globalization is a phenomenon experienced by many industries in the present global economy. The global production network (GPN) framework can be used to explain and interpret the phenomenon of transnational firms' adaptation strategies. Due to market saturation in their home countries, retailers began to expand into East Asia in the 1980s. However, cultural differences and legislative limitations created barriers and restrictions for the transnational retailers making this transition. How do firms overcome these challenges? Through a case study of Costco in Taiwan, this research investigates the ways in which retailers adapt their strategies with regard to three concerns: site decisions, product mix selection, and supply network consolidation. The results shows that Costco opted for a strategy of lesser localization in all three domains. This research provides evidence to support this characterization along with examples of Costco's localization strategies via a case study and focuses on the issue of the balance between localization and standardization in the GPN framework.
Date: December 2010
Creator: Yeh, YunLung

Gracias a La Nacionalización De Los Hidrocarburos: a Critical Analysis of Bolivia’s Transition to Compressed Natural Gas

Description: This paper critically analyzes the implementation of compressed natural gas and the ways in which it creates discourse in urban Bolivia. The rapidly developing nation is keen on making ubiquitous use of compressed natural gas a reality by issuing subsidies, citing increased mobility, savings, and environmental stewardship as the primary motives. Currently, eight out of every 10 public vehicles in Bolivia are powered by compressed natural gas. Through semi-structured interviews, questionnaires and secondary data collection, this paper elucidates the transitional process of building a natural gas-based transport network through discursive governance. This work draws on the critical discourse analysis literature to dissect disaggregated modal preference data, government documents, and news articles collected in Santa Cruz, Latin America's second fastest growing city. Moreover, this paper identifies and examines the ways in which the counter-discourse impacts the transformation of the country’s energy matrix. Results show that Bolivian automobile owners are reluctant to convert their automobiles, despite reduced transportation costs, stating that minimal compressed natural gas infrastructure exists outside of urban areas, and the conversion damages their vehicles’ motor. Additionally, the research reveals that automobile owners are currently the main beneficiaries, though respondents who do not posses an automobile speak more favorably of natural gas. Finally, this research illustrates that the compressed natural gas-oriented policies encourage personal automobile use that continues to drive socio-spatial segregation of Santa Cruz’s residents. Thus, the compressed natural gas discourse helps shape the urban landscape by persuading the public to consume domestically extracted and manufactured natural gas.
Date: May 2015
Creator: McCollum, Jerl Levi

Hurricane Storm Surge Sedimentation on the McFaddin National Wildlife Refuge, Texas: Implications for Coastal Marsh Aggradation

Description: This study uses the storm surge sediment beds deposited by Hurricanes Audrey (1957), Carla (1961), Rita (2005) and Ike (2008) to investigate spatial and temporal changes in sedimentation rates on the McFaddin National Wildlife Refuge in Southeast Texas. Fourteen sediment cores were collected along a transect extending from 90 to 1230 meters inland from the Gulf Coast. Storm-surge-deposited sediment beds were identified by texture, organic content, carbonate content, the presence of marine microfossils, and Cesium-137 dating. The hurricane-derived sediment beds are marker horizons that facilitate assessment of marsh sedimentation rates from nearshore to inland locations as well as over decadal to annual timescales. Near the shore, on a Hurricane Ike washover fan, where hurricane-derived sedimentation has increased elevation by up to 0.68 m since 2005, there was no measurable marsh sedimentation in the period 2008-2014. Farther inland, at lower elevations, sedimentation for the period 2008-2014 averaged 0.36 cm per year. The reduction in sedimentation in the period 2008-2014 on the nearshore part of the marsh is likely due to reduced flooding in response to increased elevation from hurricane storm surge sediment deposition. These results provide valuable knowledge about the sedimentary response of coastal marshes subject to storm surge deposition and useful guidance to public policy aimed at combating the effects of sea level rise on coastal marshes along the Gulf of Mexico.
Date: May 2016
Creator: Hodge, Joshua Brian