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Stochastic Multimedia Modelling of Watershed-Scale Microbial Transport in Surface Water

Safwat, Amr M
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406880416

Abstract Details

2014, PhD, University of Cincinnati, Engineering and Applied Science: Environmental Engineering.
Events of rainfall have been reported to result in increased concentrations of biological and chemical contaminants transported through streams and channels. The heterogeneous distribution of the contaminants in time and space presents interesting modeling challenges. Incorporating and pinpointing sources of increased microbial contribution to our water bodies would effectively help in the decision making process. There are many factors and unknown processes that we still do not fully understand and are not able to describe using deterministic approaches and methods. One way to account for these uncertainties is by utilizing well established stochastic based models to be able to predict the risks that might result from increased microbial influx to our recreational water systems. The goal of this work was to develop a new, GIS-integrated stochastic framework to model the fate and transport of microbial pollutants in surface waters. The resulting tool is intended for assessment of the spatial and temporal distribution of microbial water contamination risk during and following individual storm events on the watershed scale. As part of the work, a new data management system (DMS) was developed and tested. The DMS focuses primarily on standardizing hydrological data for easy access to facilitate sharing. All steps that were taken to setup and populate the Observations Data Model are described. After completion of the DMS, a framework that enables modeling and prediction of microbial concentrations and behaviors during individual rainfall events was developed based on a ArcGIS tool called the Schematic Processor. This framework was developed to include both a stochastic model and a soil erosion model to provide a more accurate picture of concentrations in time and space. The resulting new model contains expanded capabilities that incorporate contaminant interactions with suspended sediments in hillslopes and channels, thus providing time series of concentrations at any given position in a subwatershed. Finally, a second model was developed to bridge the microscopic dynamics of individual microorganisms to macroscopic behavior of microbial ensembles. The distribution of microbes in the watershed was described as a non-homogeneous Poisson random field. Derivation of parameters of this field allowed for computation of water contamination risk in space and in time. Built on the recently published report on the developed and tested data management system, the two new microbial transport models are complementary in that they provide information both on the dominant processes that govern microbial transport and on risk of water contamination in space and in time. Both frameworks were successfully applied and tested with two different microbes E. coli and Enterococci for two individual rainfall events that took place in 2005 in the Shepherd Creek watershed in Cincinnati, OH. The two models were calibrated and simulated the spatial and temporal distribution of E. coli and Enterococci. The results showed high risk of microbial exceedance of EPA recommendation for recreational water use in the first hours following the rainfall events. Decision makers will be able to use the developed models for future microbial risk predictions.
Lilit Yeghiazarian, Ph.D. (Committee Chair)
William D Shuster, Ph.D. (Committee Member)
Timothy L Whiteaker, Ph.D. (Committee Member)
Margaret Kupferle, Ph.D. P.E. (Committee Member)
George Sorial, Ph.D. (Committee Member)
137 p.
Environmental Engineering
Stochastic Multimedia Modelling; Environmental data management system; Hillslope scale; Soil erosion; Non-homogeneous Poisson random field; Microbial risk predictions

Recommended Citations

Citations

  • Safwat, A. M. (2014). Stochastic Multimedia Modelling of Watershed-Scale Microbial Transport in Surface Water [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406880416

    APA Style (7th edition)

  • Safwat, Amr. Stochastic Multimedia Modelling of Watershed-Scale Microbial Transport in Surface Water. 2014. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406880416.

    MLA Style (8th edition)

  • Safwat, Amr. "Stochastic Multimedia Modelling of Watershed-Scale Microbial Transport in Surface Water." Doctoral dissertation, University of Cincinnati, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406880416

    Chicago Manual of Style (17th edition)

ucin1406880416
421
© 2015, some rights reserved.Creative Commons License Stochastic Multimedia Modelling of Watershed-Scale Microbial Transport in Surface Water by Amr M Safwat is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Cincinnati and OhioLINK.