Rising to the Sea-Level Challenge

Climate change is one of six key trends driving ASCE’s Future World Vision scenario-planning model. Already, right now, in the present world vision, climate change –  specifically sea-level rise – is driving demand for flooding solutions in Southeast Florida.

Civil engineers in the region, along with local governments and cooperative efforts like the Southeast Regional Climate Change Compact, the Resilient Utilities Coalition and the Florida Climate Institute, are developing innovative mitigation strategies.

Jayantha Obeysekera, Ph.D., P.E., D.WRE, F.ASCE, director of the Sea Level Solutions Center at Florida International University, and Mike Sukop, Ph.D., P.G., C.Hg., a professor at FIU, will be discussing some of these strategies during a session at the ASCE 2019 Convention in Miami this October. They spoke recently with ASCE News.

Read more about Future World VisionASCE News: What are you seeing right now in Southeast Florida as far as sea-level rise issues?

Jayantha Obeysekera: Southeast Florida is one of the most vulnerable places in the country for flooding from sea-level rise and storm surge. In the last few years we’ve seen quite frequent “King Tide” flooding typically in the month of October. There are places like Miami Beach. Twice a day the water will come through the storm drainage network into the streets. All the roads are flooded, and the skies are blue. It’s what we call sunny day flooding.

That has been a problem, and people were really unhappy about the situation. The city has been building flood protection infrastructure by putting pumps and raising sea walls. So that’s one example.

And then Southeast Florida also has this flood protection system designed and built by the federal government, the U.S. Army Corps of Engineers, in the 1950s and ’60s, and they did not think about sea-level rise at the time. So now parts of the flood control system cannot be operated because the sea has risen by five, six inches. And that matters in South Florida, because we have very flat topography, sandy soils and a high water table.

It’s a critical situation. Local governments are trying to come up with solutions to adapt to this sea-level rise phenomenon.

And to make things worse, we have compound flooding, which is a topic of interest among the civil engineering community. You have this compounding effect of rainfall, sea-level rise, and storm surge. And particularly in South Florida, you also have the groundwater table coming up at the surface. So all those factors sometimes act together to make flooding worse.

As civil engineers we need to come up with guidelines and standards for planning and design.

Flooding in Miami, FL
Miami has seen the occurrence of “sunny day floods” in recent years.

ASCE News: What are some of the most effective mitigation strategies?

Obeysekera: Miami Beach will have what we call backflow preventers. When the tide is high, they will have these preventers to stop seawater going into the streets. It’s a one-way route system. Then they will raise the sea walls. But more importantly, to get the rainwater out, they have built some pump stations already.

Mike Sukop: A lot of the South Florida-Miami area really came out of water to begin with anyway. My home is constructed adjacent to a lake which was dug in order to obtain fill material to raise the land that used to be the Everglades. And we have many examples of islands in Biscayne Bay where very expensive real estate was also created by man. Our port is a great example too.

All these things were basically built out of nothing on top of the water before, so there’s been a history of coping with high water levels by raising the ground elevation. In the long term, I think that may be one of our key solutions.

ASCE News: Have you seen progress toward some of these fixes? Is the future bright?

Obeysekera: We are very optimistic, particularly if the local governments use the right scientific approach to deal with the adaptation problem. There are a lot of uncertainties and projections.

We are working to develop and apply what we call dynamically adaptive policy pathways. Because of the uncertainty you don’t want to build a structure for 100 years right up front. It has to be an incremental adaptation. You start with a structure to get through a couple of decades, while keeping an eye on the data so you know what will be needed decades into the future. And you do things now that will not prevent you from doing those bigger things later.

Learn more about Future World Vision at the ASCE 2019 ConventionSo this dynamically adaptive pathway tells what we should build first, what you should build next. It’s a phasing of adaptation strategies.

I must say people are not used to thinking along those lines. And I think civil engineers can play a big role in developing those strategies because they can look at the uncertainties and projections, and investments and solutions.

Sukop: The Southeast Florida Regional Climate Change Compact has been viewed as a model of cooperation between county-wide governments. It goes all the way from Palm Beach to Broward, Miami-Dade and Monroe County down in the Keys. This has been a national model for the type of cooperation that’s going to be needed to address these larger-scale problems.

So, personally, I have a lot of optimism. I think there are going to be a lot of things that are going to be implemented. We haven’t figured out exactly how it’s going to be rolled out, but these are the things we’re thinking about all the time: how the different adaptation measures can be applied so that the region can continue to be habitable and economically viable.

Learn more about the ASCE 2019 Convention.

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