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Submarine Groundwater Discharge in t...

Carlson, Charles Louis.

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Submarine Groundwater Discharge in the Southern Chesapeake Bay: Constraints from Numerical Models.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Submarine Groundwater Discharge in the Southern Chesapeake Bay: Constraints from Numerical Models./
Author:	Carlson, Charles Louis.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
Description:	75 p.
Notes:	Source: Masters Abstracts International, Volume: 81-03.
Contained By:	Masters Abstracts International81-03.
Subject:	Hydrologic sciences. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=13862385
ISBN:	9781085790932

Submarine Groundwater Discharge in the Southern Chesapeake Bay: Constraints from Numerical Models.
Carlson, Charles Louis.

Submarine Groundwater Discharge in the Southern Chesapeake Bay: Constraints from Numerical Models. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 75 p.

Source: Masters Abstracts International, Volume: 81-03.

Thesis (M.S.)--Old Dominion University, 2019.

This item must not be sold to any third party vendors.

Terrestrial and oceanic forces drive fluid flow within the coastal zone to produce submarine groundwater discharge (SGD). Groundwater flowing from the seabed serves as a significant pathway for contaminants and nutrients, producing an active biogeochemical reaction zone. In order to quantify the importance of SGD in geochemical and hydrologic budgets for the lower Chesapeake Bay, three coastal Virginia transects (southern Eastern Shore, Lafayette River, and Ocean View beach) with different topographic gradients were modeled using similar boundary conditions and consistent treatment of hydrogeologic layers. A sensitivity study was performed on the variables of recharge rate, seawater density, and hydraulic permeability. Each two-dimensional transect is approximately 5 km in the shore-perpendicular direction with vertical elevations ranging from 10 m above sea level to 50 m below sea level. A pre-processing suite of code displays NOAA topography and bathymetry data, allows the user to identify a desired transect, and outputs a cross-sectional numerical domain for a series of steady-state calculations solved by a USGS program called SUTRA. SUTRA's hybrid finite element and finite difference method computes buoyancy-driven flow of variable-density groundwater, solves the coupled solute transport equation, and predicts areas of discharge and recharge across the nearshore coastal zone. Model results suggested SGD in all transects, with common flow pattern characteristics including freshwater discharging below the elevation of sea level, seawater recirculating in steep bathymetry, and intervening zones of relatively low flow. Although fluid velocity at the low tide mark was significantly dependent upon the slope of the transect, response to recharge rate was small over the range of modeled values. Permeability had the greatest effect on SGD; varying hydraulic conductivity by over an order of magnitude produced similar magnitude changes in discharge. Overall, this series of models provides a framework for identifying zones of high groundwater flow, reveals the variability of SGD rates between locations, and suggests which field measurements would be most valuable to better constrain the geochemical groundwater contribution to the coastal zone.

ISBN: 9781085790932Subjects--Topical Terms:

3168407
Hydrologic sciences.
Subjects--Index Terms:

Chesapeake Bay

Submarine Groundwater Discharge in the Southern Chesapeake Bay: Constraints from Numerical Models.
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100 1 $a Carlson, Charles Louis. $3 3546117
245 1 0 $a Submarine Groundwater Discharge in the Southern Chesapeake Bay: Constraints from Numerical Models.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2019
300 $a 75 p.
500 $a Source: Masters Abstracts International, Volume: 81-03.
500 $a Advisor: Georgen, Jennifer E.
502 $a Thesis (M.S.)--Old Dominion University, 2019.
506 $a This item must not be sold to any third party vendors.
520 $a Terrestrial and oceanic forces drive fluid flow within the coastal zone to produce submarine groundwater discharge (SGD). Groundwater flowing from the seabed serves as a significant pathway for contaminants and nutrients, producing an active biogeochemical reaction zone. In order to quantify the importance of SGD in geochemical and hydrologic budgets for the lower Chesapeake Bay, three coastal Virginia transects (southern Eastern Shore, Lafayette River, and Ocean View beach) with different topographic gradients were modeled using similar boundary conditions and consistent treatment of hydrogeologic layers. A sensitivity study was performed on the variables of recharge rate, seawater density, and hydraulic permeability. Each two-dimensional transect is approximately 5 km in the shore-perpendicular direction with vertical elevations ranging from 10 m above sea level to 50 m below sea level. A pre-processing suite of code displays NOAA topography and bathymetry data, allows the user to identify a desired transect, and outputs a cross-sectional numerical domain for a series of steady-state calculations solved by a USGS program called SUTRA. SUTRA's hybrid finite element and finite difference method computes buoyancy-driven flow of variable-density groundwater, solves the coupled solute transport equation, and predicts areas of discharge and recharge across the nearshore coastal zone. Model results suggested SGD in all transects, with common flow pattern characteristics including freshwater discharging below the elevation of sea level, seawater recirculating in steep bathymetry, and intervening zones of relatively low flow. Although fluid velocity at the low tide mark was significantly dependent upon the slope of the transect, response to recharge rate was small over the range of modeled values. Permeability had the greatest effect on SGD; varying hydraulic conductivity by over an order of magnitude produced similar magnitude changes in discharge. Overall, this series of models provides a framework for identifying zones of high groundwater flow, reveals the variability of SGD rates between locations, and suggests which field measurements would be most valuable to better constrain the geochemical groundwater contribution to the coastal zone.
590 $a School code: 0418.
650 4 $a Hydrologic sciences. $3 3168407
650 4 $a Geophysics. $3 535228
653 $a Chesapeake Bay
653 $a Groundwater
653 $a MATLAB
653 $a Numerical modeling
653 $a Sensitivity modeling
653 $a SUTRA
690 $a 0388
690 $a 0373
710 2 $a Old Dominion University. $b Ocean/Earth/Atmos Sciences. $3 3433936
773 0 $t Masters Abstracts International $g 81-03.
790 $a 0418
791 $a M.S.
792 $a 2019
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=13862385