The scientific side effects of Superstorm Sandy

When Superstorm Sandy swept across much of the eastern seaboard it left massive damage. On Fire Island, New York, the storm left behind a breach or a land gap that threatened local communities. The National Park Service was left with a decision, close the gap or wait and see what happens. Five years later, we visit the island to see how nature took its course.

TRANSCRIPT

When Superstorm Sandy swept across much of the eastern seaboard, it left massive damage.

On Fire Island, New York, the storm left behind a breach, or land gap, that threatened local communities.

The National Park Service was left with a decision -- close the gap or wait and see what happens.

Five years later, we visit the island to see how nature took its course.

Take a look.

On a day like this, the sea alongside New York's Fire Island is calm, but when Superstorm Sandy hit in 2012, this water was whipped into a frenzy.

The storm hit during high tide, causing maximum possible damage to the area, including the long stretch of land that separates the ocean from the bay.

The sea level rose, the bay level sank, and large waves gnawed away at the sand dune that separated the two.

A path of water formed over the dune and tall waves rushed to the bay below.

The erosion created a divide in the land which became this breach in the barrier island.

In the wake of the storm, the Army Corps of Engineers estimated the cost of filling the old inlet breach to be in the millions.

The National Park Service oversees Fire Island National Seashore, so it was left with a big decision -- let the breach remain or artificially close it.

Kaetlyn Jackson is Fire Island National Seashore's Park Planner.

In the planning process, we came up with three alternatives that we analyzed, and one was to close it immediately with mechanical processes, to let it go, let nature take its course, don't touch it, don't look at it, just let it go and don't worry about it, walk away.

And then the third one was to let natural processes take their course as long as possible, and that we would know whether we need to close it based on science.

Following Superstorm Sandy, there was a lot at stake.

Residents were concerned that the breach in the barrier island could cause more flooding in nearby housing developments.

Then there was the impact to the ecosystem.

For the first time in over 100 years, water in this area began flowing freely between the ocean and Bellport Bay, a polluted section of the Great South Bay surrounding the breach.

There was pressure.

The concern about flooding impacts on the south shore of Long Island was real.

Typically, the Great South Bay has its challenges with water quality.

We have a lot of brown tides occur every year, and that's of a concern for the ecosystem.

A lot of plant life and wildlife can't survive in those kinds of conditions.

But Jackson's team knew that breaches are naturally occurring and usually close on their own over time, constantly exposed to waves that move the sand back and forth reshaping the land.

Fire Island and the barrier islands on the south shore of Long Island have historically been breached.

That's just how a barrier island system functions -- it's always moving, it's very dynamic, and part of that natural process is breaching.

That's important, because Fire Island National Seashore is a federally designated wilderness area, meaning the national park should remain unimpaired by humans as much as possible.

So the National Park Service was allowed 60 days after the storm hit to monitor and evaluate effects of the change as it related to flood risks and the stability of the ecosystem.

Charles Flagg is a professor of Marine and Atmospheric Studies at Stony Brook University.

He's been monitoring the Great South Bay since 2006.

So, in that period, they looked at our data.

We had been collecting data for the previous 6 years, and we were collecting data after the breach, and we showed that things like the tide range had not changed.

Not only that, but the pollution in Bellport Bay had actually improved from the influx of ocean water.

It was clear that the exchange between bay and ocean water was clearing up at least Bellport Bay.

So Bellport Bay was much cleaner than it had been for the past 30 years.

We can say that there has been an increase of species and species richness.

So there are more animals using the area in greater numbers than before.

Because the ocean and the Great South Bay is mixing water, the temperature is a little bit warmer in the winters, cooler in the summers in the bay.

It has increased the salinity locally in the bay, and also affected a little bit of the distribution of how water moves throughout the bay.

It's not a good or bad thing.

It's a change, and depending on the species you are, it might be a good or bad thing, but overall, it's a natural process that we're excited to see and continue to research.

So the park service left the old inlet breach alone.

Now, years after Superstorm Sandy, Jackson says her team still meets monthly to discuss engineering plans for closing the break in the barrier land.

The idea is that any breach that happens on Fire Island National Seashore will ultimately be closed because of the natural processes.

The question is -- When?

So we have this planning process to give us different options in case we start seeing impacts to the natural and cultural resources to Fire Island, and negative impacts to the south shore of Long Island, so if there were flooding impacts or damage.

By its very nature, the breach is constantly shifting, so if it does need to be closed, there is no way of knowing how large the gap would be at that point, or even its precise location.

That's why regular monitoring is key.

So any design will have to be done when we know we have to close it based on the size, the location, the depth, and all of those other factors.