Geography Commons^™

Modeling Spatial Distributions Of Tidal Marsh Blue Carbon Using Morphometric Parameters From Lidar, Bonnie Turek

Masters Theses

Tidal marshes serve as important “blue carbon” ecosystems that accrete large amounts of carbon with limited area. While much attention has been paid to the spatial variability of sedimentation within salt marshes, less work has been done to characterize spatial variability in marsh carbon density. Driven by tidal inundation, surface topography, and sediment supply, soil properties in marshes vary spatially with several parameters, including marsh platform elevation and proximity to the marsh edge and tidal creek network. We used lidar to extract these morphometric parameters from tidal marshes to map soil organic carbon (SOC) at the meter scale. Fixed volume …

Factors Affecting Groundwater Nitrate Concentration In Madinah Area, Saudi Arabia, Majed M. Almutairi

Masters Theses

High levels of nitrate in groundwater are a serious problem in Madinah Area, Saudi Arabia. Identifying factors affecting groundwater nitrate contamination is important for managing groundwater quality. This study examined factors that have significant impacts on the high level of groundwater nitrate in Madinah Area. Factors examined included well-depth and land cover. Relationships between variables were explored using three statistical approaches: the Kruskal-Wallis test and two types of regression (ordinary least squares [OLS] and geographically weighted regression [GWR]).

Nitrate concentration data show that 73% of obtained groundwater samples exceeded the United States Environmental Protection Agency (EPA) maximum contaminant level (MCL) …

Modeling Channel Response To Dam Removal In Lansing, Michigan, Using Swat, Ryan Filbin

Masters Theses

The removal of dams has increased in recent decades in the United States, largely resulting from decaying infrastructure and greater efforts to restore rivers to a more natural, free-flowing state. Dam removal presents the opportunity for increased public safety, improved environmental prosperity, and improved economic prosperity in conjunction with riverfront revitalization projects. The City of Lansing, Michigan, contains two moderate-to high-risk dams along the Grand River that pose a significant risk to the surrounding area in the event of structural failure.

The Soil and Water Assessment Tool (SWAT) is applied to model the impacts of the Moores Park Dam and …

Development Of A Variogram Approach To Spatial Outlier Detection Using A Supplemental Digital Elevation Model Dataset, Zane Daniel Helwig

Masters Theses

"When developing a ground water model, the quality of the dataset should first be evaluated. Spatial outliers can lead to predictions which are not representative of actual conditions. In order to isolate misrepresentative points, a method is presented which examines the experimental variogram of a ground water elevation dataset. To define a threshold variance between pairs of ground water elevation measures, ground elevation values from a digital elevation model (DEM) are used to determine a maximum reasonable variance expected to occur on the experimental variogram. To determine appropriate DEM parameters, a separate study was also done which observed characteristic behavior …

Geophysical And Remote Sensing Applications For A Better Understanding Of The Structural Controls On Groundwater Flow In The Lucerne Valley, California, Dale R. Dailey

Masters Theses

An integrated study was conducted in the Mojave Basin to investigate the potential role of faults and basement uplifts for groundwater flow in the Mojave Desert. Observations made include: 1) Very Low Frequency (VLF) measurements across mapped (using LIDAR and Geoeye-1 imagery) fault traces showed significant radio field dip angles indicative of presence of shallow sub-vertical, sheet-like conductors; many of the VLF tilt peaks coincided with changes in the magnetic profiles; 2) Vertical Electric Soundings indicate shallow basement west of, and parallel to, the Helendale Fault and deep saturated zones east of the fault/basement outcrop (F/B); and 3) isotopic analyses …

Spatial Discrepancies Between Nhdplus And Lidar-Derived Stream Networks, Nicole Marie Samu

Masters Theses

Many organizations demand that current water resource issues necessitate improved stream network mapping for more accurate and reliable watershed analysis and modeling results, which can ultimately enable better management and policy decisions. Stream network data from the National Hydrography Dataset Plus (NHDPlus) and derived from Light Detection and Ranging (LIDAR) are each widely accepted to be of superior quality compared to many other conventional datasets. Each dataset indicates potential to improve a wide range of water resource applications; NHDPlus for its high spatial accuracy and functionality, and LIDAR-derived networks for their high resolutions. NHDPlus is publicly available and widely used; …

Pleistocene Aquifers In Coles County, Illinois, James D. Hopkins

Masters Theses

No abstract provided.