Rising seas raise concerns for St. Augustine

In the next century, sea level is expected to rise anywhere from one to five feet, putting historic landmarks, such as the Castillo De San Marcos, at risk. Photo: Katie Garwood

By Katie Garwood | gargoyle@flagler.edu

For most college students, having a pair of rain boots isn’t a necessity. But in St. Augustine, for students who aren’t equipped with rain gear, the frequent flooding of streets and sidewalks will prove to be a nuisance.

For now, extreme high tides and heavy rainfall are the culprit. But in the future, sea level rise could make flooding even worse in America’s oldest city.

“As sea level slowly rises, eventually some very low-lying areas will go under water, but more realistically — and sooner — as sea level rises several inches, it means storms and extreme high tides are going to be higher. And so just as you have flooding events now from storms or extreme high tides, as sea level rises and saturates the ground, it’s going to make those problems worse,” said John Englander, an oceanographer and a recent guest lecturer at Flagler College.

Right now, routine flooding from rain and high tides causes minor issues and inconveniences for St. Augustine. In addition to the annoyances caused by flooding, other problems are also brought on by excess water.

“[Flooding] overburdens our infrastructure,” city Engineer Reuben Franklin said. “Our sanitary sewer system, our storm sewer systems, our pumping stations, our roadways and on top of that, it kills our maintenance aspect in landscaping and killing the grass. Luckily, what we don’t have a lot of is structural flooding, where it actually damages buildings and structures, but in the future, that’s going to be more prevalent.”

Over time, slow and steady sea-level rise will intensify the flooding and the issues it causes.

“[Sea-level rise] is going to be a huge issue for every coastal city, especially for us because we are low lying, but it’s going to be an issue that the city’s decision-making, and future planning is going to have to deal with,” Franklin said.

Recent high-tide cycles caused by the supermoon phenomenon have brought flooding into downtown St. Augustine in the past few weeks. According to Matthew Brown, an assistant professor of coastal environmental science, with future extreme high-tide events in the next 50 to 100 years, sea-level rise will only make the flooding worse.

“There was so much water being piled up against the marina and the fort that water was actually backing up into the sewer drain and flooding the street,” Brown said. “So, what a lot of people worry about is,  if on top that, you factor in another one feet to three feet to five feet of sea-level rise by the century’s end.”

According to Franklin, flooding caused by the supermoon tides and other high-tide events could become more frequent for St. Augustine in the future. The water level brought on by these events could become the new normal sea level.

“I think a good example would be the supermoon tides that we have currently,” Franklin said. “Just imagine that with all this coastal flooding we’ve had and it backing up in the sewer systems, just imagine in 100 years. That’s going to be the status quo.”

A set of stairs at the Castillo De San Marcos National Monument seen at low tide (left) and high tide (right). As sea level rises, today’s high tide could be the normal sea-level. Photo: Katie Garwood

Although sea-level rise is happening, effects from it haven’t necessarily been felt yet. So for now, the city of St. Augustine is in the beginning stages of assessing the risks of sea-level rise. The city recently began working with the University of Florida on a vulnerability assessment to determine the city’s exposure to flooding and to see how various structures and buildings in the city can be protected.

One structure in particular that may be affected by sea-level rise is the Castillo de San Marcos National Monument, which has been standing since the late 1600s.

Chief of Interpretation and Education for the Castillo Steve Roberts said as of now, the National Parks Service is focused on learning about the threats sea-level rise could have on the Castillo and collecting data.

“There’s all sorts of projections out there from things like taller sea walls and levee systems to the reality that we may not be able to preserve the Castillo in the same way we are,” Roberts said.

As the city and the National Parks Service moves forward with their assessments, tourism, which the city relies on, will have to be taken into account.

“I think we are going to need to be thinking as a city and with the national parks service to really think about how the experience in the colonial district can be the best moving forward together,” Roberts said. “You’ll still be able to visit the Castillo, but what is that visit? Will it be by ferry boat instead of pulling up in the parking lot? We don’t know, but we’re just going to have to be flexible in trying to figure out, as the conditions change, what are the best ways to address the situations.”

Roberts cited a national report that estimated that if the sea level rose to the level where it resulted in the Castillo being destroyed, it would have a replacement value of $26 billion, which “basically means it’s irreplaceable,” according to Roberts. Although sea-level rise hasn’t caused these kind of issues yet, it is a risk in the coming century.

The Castillo De San Marcos seen at high tide (left) and low tide (right). During high tide events, the rock sea wall in the water is covered. Photo: Katie Garwood

“At this point, it’s really minor inconveniences, but I think what is startling is the thought that if you take what [the water level] was during these really high tides that came over the sea wall into our grassy areas and into our moat and our parking lot, if you add another meter of sea-level rise, it’s almost impossible to think about the impacts it’s going to have on these low-lying areas,” Roberts said.

Although government officials, scientists and academics are aware of the inevitability of sea-level rise, the same cannot be said for the general public.

“There’s a really big disconnect between the general public and the academic community,” Brown said. “If you took 100 scientists and put them in a room, I would say 98 or 99 of them would be pretty certain humans are having a significant effect on climate. If you look at the general public, if you took 100 members from there, that number is going to be around 30 or 40.”

According to Englander, the main cause of sea-level rise is global warming, which humans can help slow down a bit, but not entirely stop. To do that, he said humans need to put less greenhouse gases into the atmosphere by taking actions like putting solar panels on roofs, driving a fuel-efficient car or even biking to school or work. But unfortunately, these actions alone will not slow the warming. It may be good to set an example for others, but according to Englander, that’s “not going to slow the planet from warming.”

“Ultimately, it has to go way beyond that,” Englander said. “It has to become part of a global policy … We need to get at the state and federal and national levels, and we need to get incentives so that we’re all working to reduce carbon-dioxide emissions or greenhouse gases.”

While being “green” and enacting change at the state and national levels is paramount, educating the public on a large scale is an important factor.

“What we have to do as the city and as a community — it’s not the city, it’s the county, it’s bigger than ourselves, everybody is going to be impacted along the coastline — is get the word out and let people know that in the future here, we’ve got some hard decisions to be made,” Franklin said.

According to Englander, sea-level rise is a slow process, and that means there is still time to act, educate and change things to make the future better. 

“There are things we can do about [sea-level rise],” he said. “That’s what I want to hear. It’s not a simple solution, but most things in life don’t have that. This can either be one of the biggest problems we face as a world civilization or it could be one of the best opportunities, because this could challenge us to rethink our relationship to a lot of things … We need to challenge ourselves and others to think differently.”