If the numbers from environmental advocacy group Union of Concerned Scientists are to be believed, there is not much stopping “chronic inundation” of Brunswick and the Golden Isles in the coming years — the only difference being the growing percentage of land subject to regular flooding.
The study, published in the science journal Elementa, noted this sort of increasingly problematic tidal flooding is one of the most visible indicators of sea-level rise, classifying chronic inundation as the flooding of 10 percent or more of a given land mass at least 26 times a year.
Brunswick and St. Simons and Jekyll islands already deal with the king tide phenomenon. As noted by The News in November 2016 during a king tide aided by the supermoon phenomenon, water normally contained in the Marshes of Glynn took temporary possession of the parking lot of SouthEast Adventure Outfitters off U.S. Highway 17, and Jekyll Sound swamped St. Andrews Beach, up to and beyond the rocks.
What could be hard to contemplate is, if the estimates in the projections hold true, at a rate of moderate sea-level rise, Brunswick could see regular tidal flooding worse than what accompanied Hurricane Matthew nearly one out of every 10 days of the year within the next 18 years. Then that would only grow more severe with every passing year.
The eventual problem is relatively clear. As lead authors Kristina Dahl and Erika Spanger-Siegfried note in the report, “If you live in a coastal community, you know that the intertidal zone is underwater once or twice daily. You might enjoy building a sand castle in the intertidal zone, but you would not build your house in it, or a road or other infrastructure.”
And there in lies the rub. The federal government has policies and case studies for handling imprudent development in flood zones — neighborhoods in which agencies encourage the residents to move elsewhere, buy up property in a neighborhood and then demolish it — but that usually only happens after particularly devastating hurricanes and associated flooding. Increasingly flood-prone downtown and historic areas are a different matter entirely.
The flooding during Hurricane Matthew demonstrated another issue to which the authors refer — infrastructure. Water that may not be seen underground can end up bursting out of manholes several miles north of areas of above-ground flooding, which creates other problems.
However, accounting for the chronic inundation of land in the area is more problematic than, say, Charleston, S.C. While the UCS data shows today 16 percent of Brunswick land is subject to chronic inundation, the vast majority of that involves industrial areas and parts of the city that would otherwise not create regular problems for many residents.
The UCS study’s numbers also show 10 percent of usable land on St. Simons Island affected by chronic inundation at present — at an intermediate rate, those percentages are projected to increase to 19 percent by 2035 and 28 percent by 2100 for Brunswick, with 16 percent by 2035 and 35 percent by 2100 indicated for SSI.
The marshes, though, play a part in making sure salt water is not running up the streets of Old Town Brunswick at the severity seen in historic neighborhoods in Charleston. The National Oceanic and Atmospheric Administration produces regular studies on the subject.
A 2015 study published in the journal Environmental Science & Policy, for instance, looked at methods to increase coastal sea-level rise resiliency.
“When making coastal protection decisions, it’s important to recognize that built infrastructure only provides benefits when storms are approaching, but natural and hybrid systems provide additional benefits, including opportunities for fishing and recreation, all the time,” NOAA ecosystem science advisor and study lead author Ariana Sutton-Grier said in a statement.
She continued, “Natural and hybrid systems can also improve water quality, provide habitat for many important species, and mitigate carbon going into our atmosphere.”
Still, evidence indicates there is only so much marshland and artificial structures can do until regular flooding at the storm surge level of a Category 1 hurricane increases in severity, making neighborhood streets and island causeways impassable and causing additional problems within the underground infrastructure.
As noted by the UCS study’s particular focus on Coastal Georgia, “As sea level rises, the chronically inundated area in each affected community expands. In the high scenario, Savannah and Brunswick, the Georgia coast’s biggest cities, would experience roughly 13 and 22 percent, respectively, of their land area chronically inundated within the next 30 years … and those areas grow to encompass roughly 17 percent of Savannah and one quarter of Brunswick by 2060.”