UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

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2012 - 20172

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    EVALUATING RESTORATION POTENTIAL AND STORM SURGE ATTENUATION IN DITCHED AND UNDITCHED COASTAL MARSHES
    (2017) Lundberg, Dorothea June; Prestegaard, Karen; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The effects of ditching on the hydrological regime and ecosystem services of ditched coastal marshes—as well as the effects of hydrologic restoration of these systems—have yet to be extensively studied. The goals of this project were (1) to determine differences between ecohydrological processes in Ditched and Unditched coastal marshes, (2) to determine the effects of ditch plugging restoration projects on Atlantic Coast and Chesapeake Bay marsh hydrology, and (3) to evaluate Hurricane Sandy storm surge in the coastal marshes. Two separate pairs of Ditched and Unditched marshes were used in this study. The paired sites were adjacent, with similar topography, vegetation, and tidal patterns. Data collection included hydrological properties such as ditch density, tidal stage, water table fluctuations; as well as soil properties. Soil properties were similar in Ditched and Unditched marshes, while ditched marshes had lower water table elevations than Unditched marshes. Ditch plugging restoration partially restored the hydrological regime. A comparison of Chesapeake and Atlantic coastal marshes during Hurricane Sandy indicated similar storm surge elevations, but shorter durations of inundation at the Chesapeake Bay marshes when compared with the Atlantic marshes.
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    Redox and Soil Manipulation Effects on Ditch Soil Phosphorus Processing
    (2012) Ruppert, David Emmanuel; Needelman, Brian A; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Ditches increase the connectivity of landscapes to open water systems, potentially facilitating the degradation of downstream waterways. A treatment and an observational experiment were conducted to identify processes behind phosphorus (P) cycling in ditch soils. If the ditch had not undergone recent dredging soils were observed in the treatment experiment to release P to surface water whether the soil system was iron (Fe)-oxidizing or Fe-reducing. Also in the treatment experiment, Fe was released to surface water in appreciable amounts only if the soil system was Fe-reducing. From the observational experiment P release due to mineralization was inferred due to a positive trend with temperature. Also in the observational experiment Fe-reducing conditions were weakly correlated with diminished P concentrations in the ditch water. It was inferred that emergent Fe(II) released from within the soil through reductive dissolution captures P from ditch surface water upon oxidation. In the treatment experiment dredging and saturated conditions resulted in similar effluent P concentrations as drained soils that were undredged. This may explain a lack of dredging effect that was observed in the field.