Increasing rates of sea level rise based land use change has been occurring for decades. Rising sea levels have caused salt marshes, which lie at the boundary between tidal waters and terrestrial land, to begin to migrate onto private property and agricultural land. Here we attempt to determine the effectiveness of preventative measures, in this case, small earthen levees, at protecting productive uplands from marsh migration decades after being installed by property owners. We chose study sites in Somerset County, Maryland, where the levees ranged in condition from extremely degraded to actively maintained. These sites were analyzed using remote sensing products to address the question of levee effectiveness. After completing an in-depth field sampling campaign, preliminary analyses of salinity, organic matter, soil moisture, and depth to parent material indicate significant differences in soil properties landward and seaward of the levees. We found all four variables to be significantly different landward and seaward of the levees at most sites, demonstrating that the levees have historically been effective at preventing upland conversion to marsh. Based on our field observations, we also found the vegetation at each site followed patterns similar to the soil characteristics, as there was little marsh vegetation on the landward side of the levee at the site with an actively maintained levee and significant marsh growth at our abandoned levee site. We created a dataset of earthen levees in the county and used a previously published dataset of normalized difference vegetation index (NDVI) trends to test if these results could be determined remotely on the scale of the entire county. With these observations, we have concluded that the studied levees were historically effective but may be decreasing in their ability to prevent marsh vegetation growth on the landward side as sea level rises.
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