Using Resistivity to Investigate Saltwater Intrusion and Tree Mortality on Sapelo Island, GA
Faculty Mentor(s) Name(s)
Sam Mutiti
Abstract
A growing threat commonly referred to as saltwater intrusion has several drivers, such as rising sea levels, the frequency/duration of droughts, natural disasters, and anthropogenic influences, all compounded by climate change. Saline moving further inland due to these factors poses threats to freshwater environments with ecological consequences such as shifts in vegetation communities and, more visibly, tree mortality. If salt water is not readily detected, sudden loss of coastal vegetation is a visible indicator of possible inland saltwater infiltration. One of the goals of this study is to investigate the possible cause of observed tree mortality on Sapelo Island and map the extent of saltwater intrusion there. The second goal is to identify if current climatic changes potentially influence saltwater intrusion and if they threaten freshwater ecosystems and vegetation. This study used the SYSCAL Junior SWITCH 48 equipment to map the subsurface distribution of electrical resistance employing the Wenner-Schlumberger array configuration. This device allowed for a saltwater intrusion to be mapped during high and low tide events at two sites on the island (Nanny Goat Beach and Cedar Hammock Trail). Three survey lines were run at Nanny Goat Beach, and salinity data piezometers were used to measure the duration during tidal changes. It was necessary to survey the beach location to project the presence of salinity moving further inland toward saline-sensitive communities. A single-line survey was conducted at Cedar Hammock Trail due to the observed tree mortality in the inland location.
Start Date
27-3-2024 9:00 AM
End Date
27-3-2024 9:50 AM
Location
Magnolia Ballroom
Using Resistivity to Investigate Saltwater Intrusion and Tree Mortality on Sapelo Island, GA
Magnolia Ballroom
A growing threat commonly referred to as saltwater intrusion has several drivers, such as rising sea levels, the frequency/duration of droughts, natural disasters, and anthropogenic influences, all compounded by climate change. Saline moving further inland due to these factors poses threats to freshwater environments with ecological consequences such as shifts in vegetation communities and, more visibly, tree mortality. If salt water is not readily detected, sudden loss of coastal vegetation is a visible indicator of possible inland saltwater infiltration. One of the goals of this study is to investigate the possible cause of observed tree mortality on Sapelo Island and map the extent of saltwater intrusion there. The second goal is to identify if current climatic changes potentially influence saltwater intrusion and if they threaten freshwater ecosystems and vegetation. This study used the SYSCAL Junior SWITCH 48 equipment to map the subsurface distribution of electrical resistance employing the Wenner-Schlumberger array configuration. This device allowed for a saltwater intrusion to be mapped during high and low tide events at two sites on the island (Nanny Goat Beach and Cedar Hammock Trail). Three survey lines were run at Nanny Goat Beach, and salinity data piezometers were used to measure the duration during tidal changes. It was necessary to survey the beach location to project the presence of salinity moving further inland toward saline-sensitive communities. A single-line survey was conducted at Cedar Hammock Trail due to the observed tree mortality in the inland location.