- Hi there, I'm Frank Graff.

Harvesting energy from the oceans, weatherproofing our homes from climate change, and making stormwater systems more resilient to extreme weather.

We are engineering for a changing climate.

Next, on "Sci NC."

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[soft music] [soft music] - Hi again, and welcome to "Sci NC."

The signs that our climate is changing are everywhere, including more severe hurricanes and extreme weather events.

Trouble is that our homes, our infrastructure are built for a climate that doesn't really exist anymore.

Producer Rossie Izlar, explains.

[dramatic music] - [Rossie] This is what it looks like when engineers study disaster.

- We break things, we set things on fire, we throw hail.

We do all of that destructive testing, so we can find the right nuggets.

- [Rossie] I'm at the Insurance Institute for Business & Home Safety, or IBHS.

Yeah, it's a mouthful, but it's essentially a nonprofit that studies how to build better in the face of extreme weather.

That's a task that's only getting harder as we face more intense hurricanes, wildfires and tornadoes because of a warming climate.

All those threats get simulated here in this massive warehouse.

This is where the magic happens.

- Oh yeah.

This is definitely where the magic happens.

I love this space because it's very analogous to a musical instrument.

And so behind us, are the fans.

There's 105 individual fans.

Each one is slightly taller than me.

And a 350 horsepower motor.

The things that look like airplane wings that are behind us, those move back and forth, and they move in a couple of different groups.

We have to produce the gustiness of the wind.

If I simply blow the wind steady, I'm not doing what Mother Nature does every single day.

That gustiness of the wind is what really attacks our building materials and structures.

- [Rossie] The engineering required to realistically simulate weather is complicated, but the solutions that actually protect buildings can be really simple.

Let's take threat number one, stronger hurricane winds.

During a hurricane, winds can literally peel the roof off a house.

That's because the roof isn't well connected to the walls.

And when the wind gets in through a door or a window, it can just pop the roof right off.

- The key is connecting them together, so that they can perform as a system.

First story and second story walls have to be connected well and then the walls have to be connected down to the foundation.

If you simply set the building on the foundation, and you don't use anchor bolts or strap it down into the foundation properly, it's just sitting on a slider.

- [Rossie] The same goes for garage doors, which can be the most vulnerable part of the house.

- Garage doors are fascinating.

Many people have one.

And it is the largest single opening on a structure.

When the wind blows and that garage door buckles or allows wind in, now you have almost like a balloon.

You're blowing into the balloon and the pressure is increasing inside the house.

Makes it much easier to tear off the walls and the roof and whatnot when you have that amazing amount of wind trying to get in.

- [Rossie] Again, the solutions to these problems are deceptively simple, more nails or straps connecting a house's layers together, or a strong garage door that has a high wind rating.

But often it's on individual homeowners and builders to know how important these measures are before it's too late.

[wind blows] And that brings us to threat number two, torrential rain.

- So we have typical construction over here on your side, and we have fortified, more resilient construction on this side.

- [Rossie] The typical construction has basic water-resistant paper tacked down with staples, but the fortified version goes a bit further.

- This one has these nice bright green button caps, which give it more bite.

It stays on a lot better and this is a thicker material.

- [Rossie] Watch what happens when "Hurricane Rossie" rips off the typical construction.

Let's do our best here.

Whoa, that came off so easily.

That's ridiculous.

And the fortified construction.

I can't do it.

- It's a lot harder.

Yes, I'll help you with, ooh, we're pulling it.

- [Rossie] The other difference is that the seams between the plywood on the fortified version are covered with water-resistant tape, which prevents water from dumping straight into the house if the shingles are ripped off.

This is the type of information the team wants out in the world, ideally embedded in building codes, which dictate the standards buildings have to meet in specific communities.

Only 32% of counties in the US have adopted the hazard resistant building codes that are recommended by FEMA.

That's the green you see here on this map.

And many counties don't even have a building code at all.

The result is a wildly diverse landscape of construction styles depending on the builder and the location.

Plus, a warming climate means new threats in new places, including wildfire.

[energetic music] Because droughts are becoming more severe and more widespread, the wildfires that used to be seen only out West now pose a bigger threat across the country.

Wildfire is the most dramatic thing to simulate, and the team generally has the fire department on hand in case things get out of control.

- The science of wildfire is all about preventing ignition.

Mother Nature's gonna make it.

The wildland has to catch on fire in many places for the healthy ecosystem.

It just has to.

What we want to do is keep that wildland fire from igniting the suburb.

- [Rossie] The team recommends a non non-flammable roof, mesh over the vents in your roof to prevent embers from sneaking inside, and a wide bare perimeter around the house, so that means no pretty bushes lining your foundation.

- It looks beautiful right up until it catches fire, and burns and takes down your house, so take those beautiful bushes and move them out away, maybe towards the back fence where you can see them from your window.

But bushes right next to your house are little green gas cans.

- [Rossie] Information like this has become vital as home insurance premiums spike across the country and it gets harder and harder to ensure homes in high-risk areas.

- Mother Nature's telling us that things are different than they were before and we have the engineering solutions to make the homes and the communities more resilient, and we can do it.

- Flooding poses the greatest risk to lives and property from extreme weather events.

Producer Michelle Lotker has more on how engineers are working to channel all that water.

- [Michelle] This patch of grass looks just like any other patch of grass on the highway, so you might not realize that it's been engineered to prevent flooding.

- A lot of our community is engineered with a purpose.

- There is a lot on our landscape that you wouldn't even realize is a stormwater control measure until you see it filled up with water when it's raining.

- [Michelle] Check out this grassy swale next to a parking deck.

It's intentionally sloped to direct water flowing off the parking deck and sidewalk to this drain structure while absorbing some of it along the way.

Even if it doesn't look like much, if it wasn't there, you would definitely notice when it rained.

- Development does a lot to our land when we're building upon it, so I want you to imagine if you have a big open field, there might be grass, there's soil, there's trees, maybe sand, a river, all kinds of surfaces that are porous, meaning there's holes in them.

So when it rains, the water is able to infiltrate or sink into the ground, soak it up like a sponge.

But when you put a parking lot over that that formerly grass area is no longer able to sink into the ground and it's just gonna run off.

- You've heard the song "Paved paradise and put up a parking lot," right?

Well, I'm not saying parking lots are not necessary, because they are, but when that happens the net effect is you generate a lot more runoff, a factor of 10 more.

- [Michelle] So how do we deal with all of the water flowing off of all of the things that we've built?

We've engineered storm water control measures.

- The Roman methodology, the Roman mentality was get the water outta here.

That's where the term highways come from.

They were on the high points because they wanted the water off those roads.

And so for millennia, truly, we worried about just getting the water outta here and that's how runoff was managed.

But what that ended up leading to is if you went far enough downstream, you'd start having local communities getting flooded.

- [Michelle] In addition to downstream flooding, fish kills in the 1990s due to excess nitrogen in the Neuse River basin highlighted the need to manage for more than flooding.

Now we have a variety of ways to decrease volume, speed and contaminant levels in stormwater runoff, and they all work a little differently.

- Stormwater control measures very, sort of simply, they will stop, temporarily hold, and then usually slowly release runoff.

- [Michelle] And they can be tailored to fit what a developed area needs.

Too many nutrients in the runoff?

A wetland is a good option.

Need a low maintenance way to manage runoff from a parking deck?

A grassy swale might be the answer.

High volume flows?

Maybe a regenerative stormwater conveyance, like this one, would do the trick.

And maybe you've heard of a rain garden.

- It's our most common practice on campus.

Engineers, we like to refer to them as bioretention cells.

You tend to see them in parking lots because they also satisfy landscaping requirements.

The idea is there's a media, which is a specialized soil mix.

- [Michelle] This soil mix can support plant growth, but also allows water to pass through quickly.

And it traps pollutants like nitrogen and phosphorus.

Below the rain garden, is a collector pipe that delivers the water to a nearby creek.

- We had a pretty significant intense rain about two hours ago.

I thought we might see some water ponded in it.

No.

I love it.

I love it.

- [Michelle] But even with measures like this in place, flooding is still a problem.

And as the climate changes, we're dealing with even more storm water.

- The hurricanes have been moving slower, typically, across our state, and dumping a lot more water than historically has been observed.

- For example, Goldsboro, North Carolina has been hit with three record breaking storms since the '90s with Hurricanes Floyd, Dennis, and Florence.

- Now you can calculate the odds of that just randomly happening.

And, I mean, the odds, I mean, it's possible, but you have to understand that it might happen once over the course of recorded history.

So either we're really unlucky, or, there is a trend, a new trend, or a pattern, of rainfall that is really impacting us.

With the storms that we are experiencing, we're observing that storm air control measures are failing.

And by failing, I mean that the water level rises and it overtops, and causes them to erode or blow out.

A common terms is they blew out.

And then it just doesn't function at all.

- It's very important to figure out what are the points of failure in our current stormwater control measures and how we can build them to be more resilient against failing.

- [Michelle] Researchers like Naomi are taking a look at existing measures to figure out how to make them more resilient for the future.

This is one of her research sites at a rest area in Alamance County, right off of I-85.

- [Caleb] A lot of sediment built up there in the forebay.

- Right now, we're standing in the riffle-pool of the Regenerative Stormwater Conveyance system, which we call RSC for short, because that's kind of a mouthful.

Basically, it makes the flow during a rain event, the storm water runoff, less erosive by slowing the water down.

And it is capturing water from the highway, as well as from this parking lot.

It's kind of in a bowl, so this is at the lower elevation.

And all the surrounding water that's at a higher elevation is gonna roll down into it.

Right now, we're setting up our total station, and that's a surveying device.

So we're gonna use the total station to shoot a laser at a mirror, effectively.

And then it'll send it back and tell you what the elevation distance from our setup point is.

And then once I have several points, I can upload that into a program called AutoCAD, and there I can generate a 3D surface of this land.

- [Michelle] Naomi and Caleb worked their way across the site, mapping out the shape of the RSC for Naomi to compare to historical measurements from when it was built.

- [Caleb] Got it.

- Yeah, this part gets kind of repetitive.

- [Michelle] Stormwater control measures, like this RSC, aren't a set it and forget it solution.

They have to be maintained.

- Wow, that's filled up with a lot of sediment.

Yeah, that doesn't look like there's any ponding left.

It's not gonna function as well as it as intended to.

We know we can design them however we want, but they're maintained.

They're not gonna be resilient.

- [Michelle] Comparing measurements of the current elevation with historical data allows Naomi to calculate how much sediment needs to be dug out in order to return this RSC to the way it was designed.

With the data she's collected at multiple sites, Naomi can create models of stormwater measures and test them to see when they fail.

- And the way I can characterize whether they're failing or not is if the flow in from the storm is equal to the flow out of the storm because that's what we do not want.

We don't want the same amount that's coming in to be coming out immediately.

Modeling is incredibly useful in this work.

And just a few clicks of a button, I can completely redesign this bioretention cell, or a Regenerative Stormwater Conveyance system.

If I were doing this in the real world, that would take me months and lots of money to do.

I can have real storms, but I can also make my own storm.

I can't do that in the real world, so it gives you the capability to model things that you wouldn't be able to otherwise and it gives you results in seconds.

- [Michelle] What Naomi discovers could help protect communities in the future.

- With climate change happening, it's important to recognize that what a storm water control measure might be designed to withstand today might not be the same storm that we're seeing in 10, 20 years from now.

And that might sound like a long way away, but we don't know how fast climate change is gonna impact us.

And even in 10 and 20 years, you don't want to have to deal with the cost and the inconvenience of replacing the stormwater control measures, so it's better if we can build them to function today and, you know, last a long time in the future.

- Renewable energy is one of the ways to slow climate change.

North Carolina researchers are looking to the ocean to spark a green energy revolution.

- [Narrator] There is energy in the ocean.

- We are talking about the energy available in waves, tidal currents and ocean currents.

And here in North Carolina, we have a reasonable wave resource and we also have the Gulf Stream.

- [Narrator] It's a tremendous amount of energy, and it's always available.

And in a world struggling with climate change, that's an appealing combination.

- The really wonderful thing about marine energy is that it is located near population centers and it's also available in places that might not have access to some of the larger grid scale energy.

- [Narrator] But whether ocean energy is harvested to power a community or a few buildings, the reality is that tapping the energy of the sea is not easy.

- These are multidisciplinary challenges.

There's geotechnical, there's environmental, there's the hardcore mechanical engineering aspects of it.

I spent my first 30 years of my career in the Coast Guard as an engineer and working in the marine environment.

It's a challenging environment.

[soft music] - [Narrator] Salt water corrodes, materials wear out faster in the ocean.

There's also biofouling, where barnacles and other organisms build up on devices.

But the design and testing of ocean energy systems is ongoing and it's transitioning from theory to reality.

- We've had a lot of developments in some of the devices that might go in the ocean to harvest energy.

And so they've gone from theoretical ideas on paper, to actual test deployments.

- Alright, so let's bring it over to try to line it up a little bit.

- [Person Off-Camera] Aha, that's in place.

It's working.

- [Narrator] And this is one of the most promising systems for harvesting ocean energy.

- Alright, deploying in 3, 2, 1.

- [Narrator] Pulling the device behind a boat simulates a deployment in an ocean current.

So what's the device?

- So we're at Lake Norman right now.

We're here for tow testing of a tenth scale underwater energy-harvesting kite.

[soft music] - [Narrator] That's right, a kite.

It looks like an airplane, and there's good reason for that.

The kite generates power by flying in the water, but it's the flight pattern that makes it all work.

It's all about physics.

Watch what the kite does during an earlier pool test.

- So basically, the idea is you take a high lift-to-drag wing, we call it a kite, and you fly it in figure-eight or elliptical patterns, perpendicular to the prevailing flow.

And as it turns out, if that kite has a high lift-to-drag ratio, it can fly many times faster than the prevailing flow speed.

And what that means is you get significantly more bang for your buck.

- [Narrator] By flying in that figure-eight pattern, the water moves over the wings in a much faster speed.

That makes for a stronger pull on the kite, and that means more power can be generated.

- So crosscurrent flight is where you're flying perpendicular to the prevailing current.

So if your current is coming in towards your kite, instead of aligning it with the flow so that it just kind of sits there, you actually lean in and you fly patterns in that crosscurrent.

And by doing that, you use that crosscurrent to generate lift and you can fly perpendicular to it and go much, much faster than that prevailing flow.

So if it's flying, if you got a current of meter per second, you can actually fly that kite somewhere between three and seven meters per second, depending on how it's performing.

And by doing that, you generate a lot more electricity with a much smaller mass than will be required for a similar fixed space turbine.

- Pitch in in 3, 2, 1.

- [Andrew] So there are two main ways that kites generate power.

One's called ground gin, one's called fly gin.

So ground gin, which is what we're using on this system, is that kite is attached to a string, just like the kite you'd fly at the beach would be.

And so by generating all that force from flying that figure-eight really fast, you actually can spool out that winch and there's a generator on the winch harnessing all of that force that you're spooling out with.

- [Narrator] All that power is used to spool and unspool a cable.

The cable is turning a turbine and that generates power.

- The other way that kites generate power is something called fly gin, which is where instead of spooling out a winch, you fly at a constant tether length and there are turbines on the kite.

And so you're just flying that pattern faster than the prevailing flow, spinning the turbines, and generating electricity on board and sending it back through your string up to some sort of battery.

- We change the design of the kite depending on the application.

So for example, it might be harvesting current energy from the Gulf Stream where the ocean currents are relatively swift, up to four knots, or two meters per second, even six.

Or it might be in a tidal inlet, where the currents can get up to, you know, three, four meters per second, eight knots, six, eight knots.

Or it might be in the deep ocean, where the currents are much slower.

And so for example, if we're developing a kite to harvest energy in the Gulf Stream, the kite might not have turbines on the wings.

The kite might generate energy by being on a tethered winch.

If you're putting the kite in the open ocean where the currents aren't that strong, then it's more efficient to put turbines on the wings.

- [Narrator] Kite systems could eventually be scaled up to power entire communities, but for now, researchers want to test the kite system by powering navigational instruments, like buoys.

Kites can also power oceanographic science systems deployed in the ocean.

- We're not quite scaling up to what we call maybe grid scale, which would be how can we put something in the ocean and power all of your homes, right?

At this point we're looking more at niche applications, like how could I put something in the ocean that would power this device to make observations for more than the two years that the batteries will do that?

- [Narrator] But researchers say new discoveries are helping them build an industry that's labeled the blue economy, and they're building it from scratch.

- So we've had successful deployments short-term, and now we're looking towards some of the materials questions to build these things to go in the ocean for maybe a year or several months.

And we're just making progress.

- Now to nature's engineering.

Here's entomologist, Adrian Smith from the North Carolina Museum of Natural Sciences.

[soft music] - This is one of the coolest insect predator prey interactions I've ever filmed.

Let me introduce you to this, a rove beetle in the genus stenus.

And the thing it's about to attack is this, a tiny springtail in the genus folsomia.

Watch what it does.

Stenus beetles have a projectile mouth part that works kind of like a sticky harpoon and they shoot it at their prey.

Here, let me show you what that footage looks like again.

It happens fast.

This sequence you're seeing was filmed at 6,000 frames per second.

After the prey is caught, the beetle retracts its mouth part and begins its feeding process.

One thing that makes that footage interesting is how small and fast everything is.

This little square of sand is where that beetle lived while it was here in the lab and where I filmed sequences.

Here, let me show you what it looks like in real time.

First, a couple misses.

[soft music] Here, are both those shots going frame by frame.

In both of these, the mouth part goes from retracted to fully extended in just a single frame.

And here, in real time, are two successful prey captures.

[soft music] The attack of the stenus beetles has to be fast because their prey have one of the fastest known animal escape jumps.

This is them.

This is one of our springtail colonies.

And you can see how fast they are when I move the substrate and they scatter away by jumping.

Here's what that escape jump looks like in slow motion.

They have a spring-loaded appendage folded underneath their bodies that they use to fling themselves several body lengths into the air and away from danger.

The stenus beetles are able to catch them because they don't need to touch their prey before they strike.

With their huge eyes, they visually orient themselves and can strike from a distance.

This one shoots its harpoon into a crevice in the sand and successfully pulls out a springtail.

It's able to do that even while the springtail is moving and bumping into the sand because their mouth part ends in a pair of ultra sticky pads.

The stickiness comes from both microstructures at the ends of the pads and an adhesive secretion that they're coated in.

Other insects that have fast moving mouth parts to catch springtails, like trap-jaw ants, have to get closer and even touch the springtails before they attack.

This can give the springtail time to sense the predator and jump away.

With a stenus attack, it's likely the springtail has no idea what's coming and no time to react.

Now there are a bunch of other cool things to know about these beetles.

One amazing thing is that there are over 3000 described species within the genus stenus, which means there are more species of beetles like this than there are all praying mantises.

If you want to go on a search for one yourself and experience this kind of satisfaction when you see one, you might search in places like this, around the edges of streams and amongst the rocks.

And if you're lucky, you might also see them doing their other special trick of skimming across the surface of the water.

I haven't seen this yet, but it's on my list.

So with any luck I'll find more of those beetles.

But for now, thanks for watching.

- That's "Sci NC."

I'm Frank Graff.

Thanks for watching.

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