Date of Award

Summer 2023

Document Type

Open Access Thesis



First Advisor

Alicia Wilson


Salt marshes migrate landward in response to sea level rise, but the rate of this migration is not constant and can be influenced by pulse disturbances. Long term observations at Sapelo Island, Georgia, show that salt marsh migration has occurred during droughts, but the mechanism for this migration is unclear. Drought is thought to influence salt marsh migration by reducing fresh groundwater discharge from the upland. Rising sea level also encroaches on the upland, which could cause movement of the freshwater lens inland. A two-dimensional numerical model was built to simulate groundwater flow and solute transport based on the Marsh Landing marsh at Sapelo Island. The model is designed to estimate salinity changes in response to climatic factors, such as drought and sea level rise. After calibration against hydraulic head and salinity data from 2016-2020, the model was used to estimate salinity and movement of the freshwater lens through the forest/marsh boundary over a 25-year period from 1998-2022 that corresponds with plant community observations at the site. Observing the changes in salinity shows drought influences seasonal variations and sea level rise caused an overall increase in salinity near the forest marsh boundary.

Included in

Geology Commons