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Earth Sciences

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Water quality

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Full-Text Articles in Physical Sciences and Mathematics

Improved Estimates Of Tributary Nitrogen Load To Casco Bay, Maine, Whitley J. Gray Aug 2019

Improved Estimates Of Tributary Nitrogen Load To Casco Bay, Maine, Whitley J. Gray

Electronic Theses and Dissertations

Over the past two decades, total nitrogen (TN) concentrations have increased in Casco Bay (CBEP 2015). The sources of the increased nitrogen are poorly understood but occur with simultaneous population growth and land use changes. The total riverine nitrogen load to Casco Bay was previously estimated by Liebman and Milstead (2012) using the United States Geologic Survey’s (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model. The SPARROW model uses watershed characteristics, regional monitoring data and nitrogen source data to estimate nitrogen loading but was not validated using measurements of nitrogen in the Casco Bay watershed. This study attempts to …


The Impacts Of Land Use And Land Cover Change On Water Quality In The Big Sioux River: 2007-2016, Dinesh Shrestha Jan 2019

The Impacts Of Land Use And Land Cover Change On Water Quality In The Big Sioux River: 2007-2016, Dinesh Shrestha

Electronic Theses and Dissertations

Between 2006 and 2012, conversion of 485,000 acres of grassland to cropland in eastern South Dakota was reported. In 2012, the Big Sioux River (BSR) running through most of eastern South Dakota was listed among the dirtiest rivers in the nation. This rating convinced state authorities to study trends of land cover changes in the BSR watershed and its association with BSR water quality with respect to increases in nitrate levels. This research i) quantifies spatial and temporal changes in the land cover types within the BSR watershed, and ii) identifies any correlation between these changes and changes in BSR …


Linking Water Quality And Beach Morphodynamics In A Heavily Impacted Tidal Creek In Myrtle Beach, South Carolina, Brittany Lynne Hoffnagle Jan 2015

Linking Water Quality And Beach Morphodynamics In A Heavily Impacted Tidal Creek In Myrtle Beach, South Carolina, Brittany Lynne Hoffnagle

Electronic Theses and Dissertations

The morphological changes of small tidal creeks, driven by coastal processes, can pose risks to infrastructure and engineered coastlines and often rely on dredging to maintain them. These changes along the beachface can negatively affect the health of associated estuaries where open exchange between the ocean and creek basins is vital. This study used Real Time Kinematic-Differential Global Positioning System equipment to survey a small tidal creek in Myrtle Beach, South Carolina that often experiences migration to the south and requires dredging to maintain an open exchange between the ocean and the estuary. In order to understand the relationships between …