College of Agriculture & Natural Resources
Permanent URI for this communityhttp://hdl.handle.net/1903/1598
The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Addressing New Stormwater Policies in the Redesign of the National Grove of State Trees at the United States National Arboretum(2012) Kreiseder, Kory Anne; Myers, David N; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The National Grove of State Trees at the United States National Arboretum is in need of redesign to meet ecological and social needs. The Grove serves as a scientific and cultural landscape and can be repurposed to serve the public as an ecological demonstration for contemporary environmental issues. In an intensive effort to clean up the local rivers of the District of Columbia and the Chesapeake Bay, the two agencies of the District Department of the Environment and DC Water have enacted stormwater runoff fees, based on impervious surface fees, on all property owners located in the District of Columbia. The redesign of the Grove is compounded by the Arboretum's need to add more parking to the area where the Grove is currently located. The objective of this thesis is to reimagine the design and interpretation of the Grove as well as address the impervious area charge assessments.Item Comparison of Infiltration Equations and their Field Validation with Rainfall Simulation(2006-12-13) Turner, Ellen Rebecca; Felton, Gary K; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Infiltration is a complex process with many factors contributing to the rate. Different approximate equations for infiltration differ in the parameters they require and predict different infiltration rate curves. Five equations including those of Kostiakov, Horton, Holtan, Philip and Green-Ampt were compared to determine which one most accurately predicted measured infiltration rates from rainfall simulation events at two different locations. Parameters were developed from measured infiltration data and laboratory analyses of soil samples. The Green-Ampt, Holtan and Philip equations with respective root mean squared errors of 0.15, 0.17, and 0.19 cmh-1, provided the first, second and third best estimates of infiltration rates, for observed infiltration data at the University of Maryland's Research and Education Center in Upper Marlboro, Maryland. An atypical infiltration curve was observed for the Poplar Hill site on the Eastern Shore of Maryland for which infiltration rate was constant and equal to rainfall rate.Item Modeling and monitoring pathogen transport through vegetated filter strips(2004-08-05) Roodsari, Gholamreza Moosapour; Shirmohammadi, Adel; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Contamination of natural waters by microorganisms directly affects public health. Field application of manure can potentially result in surface and groundwater contamination. The objective of this study was to observe and quantify the effects of vegetated filter strips (VFS) on surface and subsurface transport of fecal oviform (FC) surrogates for bacterial pathogens released from a surface - applied bovine/swine manure. The study included a field-based lysimeter equipped with multi-sensor moisture probes to monitor real-time water content through the soil profile, and with other proper instrumentation to monitor and quantify the spatial and temporal release rates of pathogenic bacteria. Another component of this study involved development and testing of a computer model to predict the surface and subsurface transport of FC. Results showed that bare plots offered no resistance to surface flow, thus FC were detected in runoff at 600 cm from the ridge of the lysimeter within 10 minutes of the rainfall initiation. Results from vegetated plots showed that vegetation substantially attenuated surface flow of water as compared to bare plots. Unlike the bare soil, the results showed that the vegetated soil surface created a much less uniform transport pattern for FC. Vegetation changed transport patterns and levels of FC concentrations much more significantly than soil texture did. Results showed that E.coli and Salmonella cholerasuis behaved similarly and resulted in similar transport patterns in both bare plots. Results also showed that both organisms demonstrated a two-stage exponential release rate with a fast release rate in the first 10 minutes of the rainfall simulation. A one-dimensional convective-dispersive equation using the continuity equation and the Manning's equation were used in MODCHOI model (a modified version of KORMIL2) to predict the surface transport of FC. To simulate the vertical movement of FC, a one-dimensional kinematic wave model was developed and used. Green and Ampt, Philip, and Schmid infiltration models were also applied to the vertical water flow movement. The models simulated the spatial and the temporal distribution of FC in runoff assuming an exponential release of FC from the manure. Simulation results satisfactorily modeled both flow and FC.