GWEN IFILL: This week marks a year since superstorm Sandy struck. More than 70 people were killed along the Eastern Seaboard. Damage totaled more than $65 billion, and it pounded New Jersey and New York City hard. It also prompted a reexamination -- a reexamination about how to prepare for future disasters.

The NewsHour’s science correspondent, Miles O'Brien, has the first of two reports for us, this on changes in New York.

MILES O’BRIEN: Hurricane Sandy brought mighty Gotham to its knees. And one year later, the people who keep this city running are scrambling to figure out how to keep it dry as storms worsen and the sea level rises.

The Consolidated Edison power substation that sits at the end of 14th street right next to the East River is about six feet above sea level.

ROBERT SCHIMMENTI, Consolidated Edison: The water and electricity doesn't mix, obviously.

MILES O’BRIEN: Most of the electricity for Lower Manhattan flows through these transformers and relays, as long as they're not underwater. For over 50 years, the 11-foot-high flood walls worked just fine, until Sandy's storm surge pushed 14 feet of water over the banks of the East River.

MAN: And the waters were coming over this.

MILES O’BRIEN: The flash point was a circuit breaker that shorted out after the saltwater rushed in.

MAN: That breaker was at a lower elevation. And as the water started to rise, that breaker flashed over, and then caused a subsequent failure at the transformer. And so then you saw this big flash of light. And there was a cascading failure because of the other relays. And then the station ended up shut down.

MILES O’BRIEN: Con Ed's vice president of engineering and planning, Bob Schimmenti, is determined tokeep this station dry whenever the next megastorm hits. They're building about 180 aluminum doors to plug any holes in the substation's protective ring.

ROBERT SCHIMMENTI: So if the same event occurred and the same storm surge occurred, there would be no customers out in Manhattan.

MILES O’BRIEN: And beneath the sidewalks, all across the city, workers are installing waterproof equipment.

MAN: Everything you saw, even if you are submerged underwater, this is all submersible equipment. If it is underwater, it will still operate normally.

MILES O’BRIEN: And they're deploying more smart grid technology that can be monitored remotely and reduce power outages.

ROBERT SCHIMMENTI: What we will do over the long-term is work with the latest climate science so that we're further protected in the future.

As more information comes in, our designs will be flexible that we can adjust, change, elevate different types of equipment, add a higher wall. We will have a different set of options that will be most cost-effective going forward.

MILES O’BRIEN: The electrical grid is just one piece of the vast infrastructure clobbered by megastorm Sandy. On the West Side of Manhattan, the phone call Verizon also got a climate change wakeup call.

CHRISTOPHER LEVENDOS, Verizon: The impact of Hurricane Sandy to Verizon was the largest impact to our line the our wire line infrastructure in our 100-year history.

MILES O’BRIEN: Chris Levendos is Verizon's vice president of national operations. Verizon world headquarters sits at 140 West Street, about 250 yards from the Hudson River, about five-and-a-half feet above sea level. The ornate art deco lobby is normally gilded and gleaming. But the night Sandy roared in, it wasn't such a pretty picture.

CHRISTOPHER LEVENDOS: We had water come in through the front and the rear doors of the building. Andthe water gets into the elevator shafts, down the stair walls and begins to fill up the five subbasements of this building.

MILES O’BRIEN: In the basement is the vault where Verizon keeps its crown jewels, telephone cables, on that night, most of them copper. Bad enough, but below the vault is a pump system that delivers diesel fuel to the emergency generators on the 10th floor.

But the pump wasn't waterproof. When it failed, the dominoes started falling. No pump, no power. No power, and these crucial machines stop working, air compressors. Verizon pumps air into its copper cables to keep water from seeping in. Water, especially seawater, destroys copper.

CHRISTOPHER LEVENDOS: The network was completely destroyed with one massive storm in one very destructive night.

MILES O’BRIEN: But there was, literally and figuratively, one glimmer of light amid the unimaginablemess. Fiberoptic cables, long thin strands of glass that transmit voice and data with bursts of light,are far more efficient than copper wires. And, best of all, they're impervious to water.

After Sandy, the company started immediately replacing the entire copper wire network in Lower Manhattan with fiber. The changeover was supposed to take years. Verizon did it in six months. In all, Sandy cost Verizon about $1 billion. And that crucial fuel pump? It's now in a watertight room with a submarine door.

Protecting New York's vulnerable and venerable subway system may be the biggest challenge of all. Sandy caused about $5 billion worth of harm to the nation's largest transit system, hardest-hit, South Ferry Station at the southern tip of Manhattan. The station was only 3 years old, built at a cost of $550million. The day after Sandy, it lay in ruins.Joe Leader is the man in charge of New York subways.

JOE LEADER, Metropolitan Transportation Authority: The water level reached this high.

MILES O’BRIEN: More than $50 million gallons of seawater came rushing into South Ferry, filling the station almost to street level.

JOE LEADER: You try and prevent it. You try and deter it, you know, and that's the best thing do. Butcan you really actually stop it?

MILES O’BRIEN: It wasn't for lack of trying. As Sandy bore down on the city, transit workers frantically fought to stem the tide with inflatable dams, sandbags and plywood. But there was no stopping thewater. Subway stations, rail yards and nine tunnels flooded.

MARC MENDE, Metropolitan Transportation Authority: The water was coming from everywhere. There was no way of stopping it. You needed Superman, I guess.

MILES O’BRIEN: Marc Mende is the general manager of the Hugh Carey Brooklyn Battery Tunnel, which normally carries cars and trucks between Brooklyn and Lower Manhattan.

MARC MENDE: We abandoned the place. We basically pulled everybody out of here.

MAN: Marc, come on. We have got to go.

MILES O’BRIEN: Here, there was little they could do; 80 million gallons of seawater gushed in. The tunnel was practically full.

Work crews managed to clean it up. They removed the ceiling tiles and replaced enough lighting, cameras and communications gear to reopen the tunnel just two weeks after the storm. But there are years of work ahead to get things back to the pre-Sandy condition.

Ten months after Sandy hit, engineers tested a water-filled emergency dam that might offer a layer of defense for the tunnel the next time. They're also considering this idea from West Virginia University, an inflatable plug. In the meantime, carpenters have erected this plywood wall at the low point where the water gushed in.

But in the long run, will plywood and inflatables and other small-scale changes be enough to protect this metropolis?

JOE LEADER: If I made this airtight and we didn't allow the $66 million gallons of water that we pumped out to come into our system, where would that water be? It would be in the streets and it would be in the basements and on the first floors of all the buildings surrounding. It's got to be a really regional issue to decide how do you deal with something like that.

MILES O’BRIEN: In June, New York Mayor Mike Bloomberg released a $20 billion plan to make the city more resilient. It calls for several small barriers at strategic locations, as well as plenty of new seawalls.

But it doesn't support construction of massive storm surge barriers like they have built in places like the Netherlands. Building structures that expensive and extensive would surely require regional, if not national, planning and support.

GWEN IFILL: Tomorrow, Miles reports from the Netherlands, a world leader in adapting to rising sea levels and severe storms.