Sullivan’s Island Home

 Marsh and Habitat Changes and Trends

Barrier Islands are more than a beach. In fact more people live on the marsh ‘shoreline’ than the ocean shoreline. Like the ocean the marsh changes; not as fast and as dramatic, but at a slow and measured pace. The changes are also more one-way toward wetter conditions - i.e., the adjacent uplands are slowing being converted to wetlands as the marsh is being converted to tidal flat and ultimately water. At a slower but continuous pace the upland habitats are likewise experiencing higher groundwater levels, which leads to the development of fresh marsh/swamps (and at some future point tidal marsh).

There are several homeowners who can attest to this, but it is a subtle process over much of the island. To provide a view of what the future 30 years will bring I have used a program call SLAMM (Sea Level Affecting Marsh Model). I won’t delve into the specifics, but quickly, it is based on SLR change (see section on SLR on Sullivan’s Island) and how much accretion is occuring in different habitats. I have done my best to use the changes measured by thousands of lidar points to define the accretion trends, which are both habitat and elevation dependent.

The SLAMM map will be constantly updated as I refine the data, but take a look to see how the other shoreline may look in a few decades.