Governments Plan for Development of Land Vulnerable to Rising Sea Level: Glynn County, Georgia

Additional background prepared by the staff of Coastal Georgia Regional Development Center and Jim Titus

Glynn County is the second-most populated coastal county in Georgia with nearly 68,000 residents, but it is the smallest in area (422 square miles). Most of the county's residents live in the City of Brunswick and on St. Simons Island. Tourism remains a popular industry within the coastal communities of St. Simons and Jekyll islands.

The county's Soil Erosion and Sediment Control ordinance requires a buffer of 50 feet from state waters. The Comprehensive Plan requires septic systems to be at least 50 feet from the marsh. The County plans additional sewer system expansions to pick up areas where older septic systems are failing on St. Simons Island. A few decades may pass, however, before residents have all been connected, given the additional costs.

Islands

Our original meetings with county staff focused on distinguishing lands where shore protection is likely from those areas where it is unlikely or precluded by existing policies. Planners indicated that the industrial and commercial portions of St. Simons and Sea islands are certain to be protected through the efforts of public and private actors and funding sources. Given the value of developed property, and the state's policy of approving seawall permit applications, privately funded protection of land will occur on Sea Island and St. Simons Island. The Sea Island Company, which owns and develops Sea Island, will almost certainly protect its properties through armoring and nourishment. DNR staff do not expect to take action to armor or nourish beaches or dunes. However, the "Village" (southern tip) area of St. Simons Island will be protected by the County with nourishment and armoring, where appropriate. Moreover, shore stabilization structures are already prevalent on private property on St. Simons Island. The Army Corps of Engineers plans to place sand (dredged from shipping channels) on the southern end of St. Simons Island. It is likely that some of this sand will accrete on the north end of Jekyll Island, due to wave action.

Although Jekyll Island is owned by the state (homeowners lease the land from the state), county planners feel that the developed portions of the island will also be protected. The Jekyll Island Authority is expected to protect and support the historic island club buildings, but the beach has never been nourished. County staff anticipate that the state will almost certainly protect the historic Jekyll Island Club complex and commercial areas. Protection is also likely in the island's residential areas.

After our draft report was complete and we had incorporated stakeholder comments, we spoke with planning director York Phillips. Mr. Phillips said that St. Simons has development that might potentially be worth protecting, but that state funding is unlikely. There is no evidence yet that property owners would collaborate on shore protection either (unlike the gated communities in South Carolina). Therefore, he suggested that we should put this in the "maybe" category, which for this study, is "shore protection likely".

Jekyll Island is a state park that has a finite number of leased lots for shoreside cottages. As sea level rises, it is more likely that the leased lot would simply be moved inland. Therefore, shore protection is unlikely in the developed areas. Sea Island does private beach nourishment. So it is reasonable to assume that property there will continue to be protected and hence it is designated as protection almost certain Mr. Phillips added that there is a 10-foot bluff along much of the ocean shore, making homes less vulnerable to flooding and slowing erosion rates. The bluffs may also make shore protection more cost-effective than would otherwise be the case, since the higher ground provides greater sand supply.

Marsh front development

There is already a tendency to elevate homes on pilings, perhaps parking cars underneath. When homes are not on pilings, often there will be some fill to ensure that yard drains to the street-and homes must have a certain elevation to ensure sanitary drainage. Homes are rarely if ever built in areas below the 6-foot NAVD given frequent flooding at that level. Therefore, if we had a good way to identify undeveloped lands below the 6-foot NAVD along the marsh areas, it would be reasonable to designate them as shore protection unlikely.

Infrastructure

The County is committed to protecting its roads by elevating them when the threat of inundation becomes apparent. Exceptionally high tides already affect roads connecting to the islands, so action will be needed in the near term. The county commissioners would act on a case by case basis to accept maintenance responsibilities for new or private roads, although a precedent has been set. Pennick Road was damaged in a storm, and the County put in culverts and now must maintain the road. Generally, if the County grades a road, or if a county school bus travels on it, then the County must accept responsibility for that road's maintenance. All evacuation routes will be maintained and protected by the county or DOT. This includes roads linking St. Simons and Jekyll islands to the mainland, I-95, US 17, and westbound routes such as US 82/GA Hwy 520, GA Hwy 99, and US Hwy 25/341/GA Hwy 27.

The existence of low-lying cemeteries will precipitate action at the county level, perhaps leading to a discontinuation of the vault system.

Future Development

We discussed future development with Eric Landon, planner II, Glynn County who works for York Phillips. He said that the county's future land use map matches the existing zoning more closely than providing a projection of the future. As a guide to future development, he suggested that it would be more useful to use the state's traffic zone analysis of projected development. He suggested the following changes to our maps.

1. Assume that all of St. Simons Island will eventually become developed. The entire island is either likely to certain to be protected.

2. Show all undeveloped lands on Colonel's Island as likely to be protected, It will probably be used by the port.

3. Change all undeveloped mainland areas east of I-95 from unlikely to likely

4. Change all undeveloped and park lands within the City of Brunswick to shore protection likely.

5. Examine the state's Traffic Analysis Zone map published on the county web site. Change unlikely to protection certain. These five polygons all are expected to have fewer than 400 additional households by 2030.

6. Again referring to the state's Traffic Analysis Zone map, change all blue within four polygons with 200-399 more households to red. Also change the blue within polygons with 50-199 expected households from blue to red.

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Governments Plan for Development of Most Land Vulnerable to Rising Sea (PDF, 7 pp., 1.3 MB) was originally published in Environmental Research Letters , Issue 3, Volume 4 (2009).