Author: Gwyneth  E  Roberts

Major: Ecology and Environmental Sciences

Graduation Year: 2019

Thesis Advisor: Thomas Belsky & Jennifer Lauren Ross

Description of Publication: This study aims to characterize the circulation patterns in short and narrow estuarine systems on various temporal scales to identify the controls of material transport. In order to achieve this goal, a combination of in situ collected data and analytical modeling was used. The model is based on the horizontal Reynolds Averaged Navier-Stokes equations in the shallow water limit with scaling parameters defined from the characteristics of the estuary. The in situ measurements were used to inform a case study, seeking to understand water level variations and tidal current velocity patterns in the Jordan River and to improve understanding of the hydrodynamic conditions and their implications for water quality. The Jordan River in Trenton, Maine is host to commercial mussel harvesting activities. These local aquaculture operations are susceptible to point source pollution and freshwater runoff induced closures, which are inherently linked to the dynamics of the estuary. Preliminary results of the data analysis indicate that ebb velocities are dominant in the intra-tidal dynamics, suggesting that subtidal (transport) velocities will be prominent in this system. Model results for subtidal flows show that there is outflow over the shoals and inflow over the channel driven by a combination of advection and Stokes drift. This pattern indicates that pollutants introduced to the system near the banks (from land-based sources) will be advected out of the system while pollutants introduced in the center (or from the seaward boundary) will be advected into the system. Thus, land-based pollutants will spend less time within the estuary. These results can be used to inform management decisions to minimize closure time throughout the harvest season.

Location of Publication:

URL to Thesis: https://digitalcommons.library.umaine.edu/honors/564/