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Khadka FINAL 8 3 2020 with cert.pdf (3.63 MB)

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Three-Dimensional Hydrodynamic Modeling to Analyze Salinity Interaction of Coastal Marshland with a Lake: A Case Study of Mentor Marsh near Lake Erie, Ohio

Khadka, Pravakar
http://orcid.org/0000-0003-0757-8342
http://rave.ohiolink.edu/etdc/view?acc_num=ysu1596468029655531

Abstract Details

2020, Master of Science in Engineering, Youngstown State University, Department of Civil/Environmental and Chemical Engineering.
Salinization is a global threat to the ecological functioning and development of the coastal wetlands. Therefore, the study of salinity interaction between the wetland and the coastal estuary is crucial to determine the salinity distribution and its variation in the coastal wetlands. This study, preeminently, was conducted to investigate the distribution of salinity in the Mentor Marsh wetland using a hydrodynamic model. The marsh is a coastal estuary system located within the Ohio Lake Basin, which has been experiencing increased levels of salinity from the early 1960s, especially after the placement of salt mine tailings near the marsh. Consequently, increased salinity has been inducing drastic vegetative change throughout the Mentor Marsh and leading to the rapid development of Phragmites australis. When dry, Phragmites australis is very prone to catch fire. Ten monitoring stations were established within the Mentor Marsh to monitor the salinity and record the hourly salinity, water level, and stream temperature data. The graphical analysis of the observed salinity was performed at several locations within the western basin of Mentor Marsh. Furthermore, a three-dimensional hydrodynamic Environmental Fluid Dynamics Code Plus (EFDC+) model was developed for the western section of the Mentor Marsh utilizing the measured data from five monitoring stations of the western basin. Most of the meteorological data needed for this model were obtained from the National Oceanic and Atmospheric Administration (NOAA). While cloud cover and precipitation data were acquired from nearby airports, solar radiation data were obtained from the United States Department of Agriculture (USDA). Similarly, bathymetry data were prepared by integrating the shoreline GIS shapefile of the Lake Erie and Mentor Marsh with a detailed survey conducted in the marina and adjoining marsh in order to appropriately represent the bathymetry in the EFDC+ model. The water levels at Lake Erie and Mentor Marsh were recorded for the open boundary conditions, whereas the streamflow at Marsh Creek was simulated from the Soil Water Assessment Tools (SWAT) model for the upstream flow boundary conditions. The EFDC+ model was calibrated for water level, water temperature, and water salinity, and the performance of the model was assessed using the statistical parameters such as Coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), and root mean squared error (RMSE). The salinity distribution under different inflows conditions, and lake level rise scenario was simulated using the calibrated model. The analysis suggested that during high flow conditions of 21.48 m3/s, the advection of the low saline water from Marsh Creek was vigorous in comparison to the diffusion of salinity mixing by tidal influence resulting in the lower salinity distribution of below 0.375 ppt within the model domain. However, during the low flow conditions of 0.392 m3/s, diffusion of salinity mixing due to tidal influence was dominant. The average salinity distribution in the Mentor Marina and Mentor Marsh was 0.655 ppt. Similarly, during lake level rise scenario, the results indicated that the salinity was significantly decreased near Lake Erie relative to the Mentor Marsh and the junction of Mentor Marsh and Mentor Marina. The average decrease of salinity from the salinity during the base run was -45.8% near the Lake Erie, -29.7% at the junction of Mentor Marina and Mentor Marsh, -21.2% in the Mentor Marsh, and -4.4% in the Marsh Creek. Presumably, the analysis suggested that the road salt applications for the de-icing purpose were the prime reason for the salinity increase in the western basin. This study can be helpful to identify the interaction of salinity between Mentor Marsh, Marsh Creek, and Lake Erie, which will eventually assist the local stakeholders for their ongoing efforts of remediation of water quality within Mentor Marsh and avoid unwanted phragmites and fire in the future.
Suresh Sharma, PhD (Advisor)
Shakir Husain, PhD (Committee Member)
Felicia Armstrong, PhD (Committee Member)
Thomas Mathis, MS (Committee Member)
92 p.
Civil Engineering; Environmental Engineering
Salinization; hydrodynamic; coastal wetland; EFDCPlus model; meteorological data; SWAT model; inflows

Recommended Citations

Citations

  • Khadka, P. (2020). Three-Dimensional Hydrodynamic Modeling to Analyze Salinity Interaction of Coastal Marshland with a Lake: A Case Study of Mentor Marsh near Lake Erie, Ohio [Master's thesis, Youngstown State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1596468029655531

    APA Style (7th edition)

  • Khadka, Pravakar. Three-Dimensional Hydrodynamic Modeling to Analyze Salinity Interaction of Coastal Marshland with a Lake: A Case Study of Mentor Marsh near Lake Erie, Ohio. 2020. Youngstown State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ysu1596468029655531.

    MLA Style (8th edition)

  • Khadka, Pravakar. "Three-Dimensional Hydrodynamic Modeling to Analyze Salinity Interaction of Coastal Marshland with a Lake: A Case Study of Mentor Marsh near Lake Erie, Ohio." Master's thesis, Youngstown State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1596468029655531

    Chicago Manual of Style (17th edition)

ysu1596468029655531
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This open access ETD is published by Youngstown State University and OhioLINK.