Theses and Dissertations from UMD

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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 give thesis/dissertation in DRUM

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

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Subject: search.filters.subject.Hydrologic Sciences

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    EFFECTS OF CHANNEL MORPHOLOGY ON FLOODPLAIN INUNDATION AND SURFACE-GROUNDWATER INTERACTIONS IN AN URBAN WATERSHED
    (2011) Lundberg, Dorothea June; Prestegaard, Karen L.; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The purpose of this study is to evaluate groundwater-surfacewater interactions between a stream and the adjacent floodplain. The study site includes two reaches on Paint Branch Creek: an incised reach with inset gravel bars and a non-incised reach with active accretion of gravels bars onto the floodplain and off channel features. Topography, sediment grain size and hydraulic conductivity, groundwater head, and floodplain/channel characteristics were measured. Groundwater head data in gravel bars and adjacent floodplains were monitored for one year to determine seasonal variations in groundwater flow directions, rates, and to develop groundwater probability curves. Identification of groundwater-surfacewater interactions and off channel features roles was determined. In the reach with attached gravel bars, water flows from the creek into the adjacent gravel bars for the most of the year. Evapotranspiration and tropical storms influence seasonal reversals in flow directions between the gravel bar and the floodplain.
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    Hydrograph separation analyses to determine runoff sources in a large, urban watershed
    (2010) Occhi, Marcie; Prestegaard, Karen L; Geology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Hydrograph separation techniques were used to determine contributions of old and new water during storm events at four sites within the urban Anacostia River watershed. Multiple storm hydrographs were successfully separated with electrical conductivity as a tracer. Total runoff correlated to rainfall, but most runoff ratios were significantly less than the percentage of impervious surfaces. Old water was a significant component of runoff at each site. Peak contributions of old water occurred earlier new water peaks, which suggests rapid transmission of groundwater to streams. New water runoff was the dominant contribution for storm events greater than 2-3 cm. Watershed topography influenced patterns of urbanization and runoff pathways. Riparian buffers along Piedmont streams appeared to be sites of infiltration of overland flow. These results indicate that electrical conductivity is an effective tracer for the evaluation of streamflow sources within large urban watersheds.
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    Modeling L-Band Microwave Emission From Soil-Vegetation System
    (2010) Joseph, Alicia T.; Kasischke, Eric; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    During a field campaign covering the 2002 corn growing season, a dual polarized tower mounted L-band (1.4 GHz) radiometer (LRAD) provided brightness temperature (T¬B) measurements at preset intervals, incidence and azimuth angles. These radiometer measurements were supported by an extensive characterization of land surface variables including soil moisture, soil temperature, vegetation biomass, and surface roughness. During the period from May 22, 2002 to August 30, 2002 a range of vegetation water content (W) of 0.0 to 4.3 kg m-2, ten days of radiometer and ground measurements were available. Using this data set, the effects of corn vegetation on surface emissions are investigated by means of a semi-empirical radiative transfer model. Additionally, the impact of roughness on the surface emission is quantified using T¬B measurements over bare soil conditions. Subsequently, the estimated roughness parameters, ground measurements and horizontally (H)-polarized TB are employed to invert the H-polarized transmissivity (γh) for the monitored corn growing season.