By Andrew Barksdale, Contributing Author
As Hurricane Florence bore down on the east coast in September 2018, staff at the North Carolina Department of Transportation knew the ominous forecast was predicting never-before-seen flooding along the coast.
Preston Hunter, who was then the New Bern-based Division 2 engineer, was concerned about the forecast and picked up the phone to call his maintenance engineer just hours before Florence made landfall. “Based on the computer predictions, it looks like Florence is going to flood parts of our maintenance yard,” Hunter said. “We need to move our equipment out of there and to higher ground right now.”
The maintenance engineer acted swiftly, relocating backhoes, motor-graders, and trucks out of harm’s way the night before Hurricane Florence struck North Carolina.
The decision proved critical – the storm flooded the only road into the maintenance yard.
“Our staff and equipment that we needed to respond to the storm would have been stranded inside the maintenance yard, had we not evacuated it,” Hunter said.
At the time, NCDOT relied on an early flood-warning system operated by the state’s Emergency Management office to forecast where buildings in coastal areas might flood.
In 2021, NCDOT launched a new early flood-warning system of its own specifically for its many roads, bridges, and culverts.
The department’s new system relies on a network of more than 400 stream gauges and new software that will enable its staff to know current flooding conditions, modeled scenarios, and forecast impacts to the road network.
The agency is using the system for the first time in the 2022 hurricane season. The system will let the agency’s maintenance officials know where to stage equipment for closing roads and alert them in real-time about where to respond to flooded roads and bridges, so they can install signs and barricades. The critical information will also benefit local emergency management officials and the public accessing the department’s DriveNC.gov website for timely, weather-related closures.
“This state-of-the-art warning system our department has created will help us be better prepared for the next major storm,” North Carolina’s Transportation Secretary J. Eric Boyette said. “Even though we’ve had some quiet hurricane seasons recently, we cannot let our guard down.”
The NCDOT developed the new system thanks to a $2 million grant the N.C. General Assembly appropriated in 2019 while the memory of Hurricane Florence was still fresh on many peoples’ minds.
Florence caused more than $240 million in damage to NCDOT’s infrastructure; and in 2016, Hurricane Matthew caused $200 million in damage to the state’s road and bridge network.
The department takes stock of lessons learned after each major storm, sharing information with emergency management officials and first-responders. The agency has bulked up its inventory of piping to replace damaged infrastructure. In some of Hurricane Matthew’s hard-hit counties, such as Bladen and Columbus near the coast, the agency embarked on an aggressive program to replace damaged culverts and crossline pipes with larger pipes that could handle more water. The upsizing was based on studies done by the department’s Hydraulics Unit. The department realized that in many cases, the addition of headwalls would make the pipes more resilient. When Hurricane Florence struck two years later, many of the newer pipes were undamaged.
Tropical systems, winter weather and other storms have previously taken a toll on roads and bridges statewide. In addition to Florence and Matthew, the state’s transportation network has sustained another $220 million in damage since 2018.
Those who study the climate say it’s only getting worse. A changing climate is spawning more frequent and more severe storms that will continue to threaten the viability of the state’s transportation network. As a result, NCDOT is now designing, building, and planning for what it terms as “the new normal.” These days, many roads, bridges, and culverts are built to withstand the next major storm. The concept of building safe, more resilient infrastructure is at the forefront of everything NCDOT does.
“Public expectations are shifting, and that will impact how our industry operates and plans for the future,” said Chris Peoples, the department’s chief engineer. “The people we serve expect infrastructure to be resilient to changing weather patterns and ready for emerging technologies.”
The issue is critical for a state like North Carolina, which has the second-largest network of state-maintained roads in the United States, behind only Texas. NCDOT is responsible for maintaining more than 81,000 miles of roads and over 15,000 waterway bridges and culverts.
Flood Risk Study
In 2020, the department completed a flood resilience feasibility study, primarily for Interstates 40 and 95. Those are the major corridors that also serve as hurricane evacuation routes. The two interstates were closed to traffic in both directions for several days due to rising floodwaters from Hurricane Matthew in 2016 and two years later during Florence.
In particular, I-95 flooded at 10 locations over a 65-mile swath between Lumberton and Benson during Hurricane Florence.
The assessment identified three existing projects in the agency’s 10-year plan that would require elevated roads and longer and higher bridges. The idea is to ensure roads and bridges are more resilient against future flooding. The resiliency measures were estimated in 2020 to cost an additional $128 million combined.
Also, seven new projects were identified to make I-40 between Benson and Wilmington more resilient at a combined cost of $170 million – mostly by elevating the roadway so it could withstand heavy flooding.
Three contracts by NCDOT are underway to widen portions of I-95 south and north of Fayetteville. Contractors will raise the I-95 bridges that span the Lumber River by 10 feet. The Lumber River flooded and resulted in a days-long closure of the interstate in both directions during Florence and Matthew. Some of the highway around Lumberton will be built on higher grade, anywhere from 1.5 feet to 10 feet.
Another contractor is constructing new I-95 bridges that will be 8-feet higher over the Black River, which also flooded the highway north of Fayetteville during Florence.
According to NCDOT’s state hydraulics design engineer, Matt Lauffer, resiliency measures have increased construction costs for the I-95 corridor by 11%. He said national research on disaster damage and federal government spending shows that every $1 spent on resiliency is worth $4 to $6 in future mitigated damage.
“We are doing a lot more risk assessments as we design new highways, and I-95 is a great example of that,” Lauffer said. “We are looking at other highway corridors in our state, and using complex hydraulic modeling and next-generation design tools.”
Transportation leaders in North Carolina aren’t just focusing on improving infrastructure for the next big hurricane. They also recognize that emerging technologies, such as electric and autonomous vehicles, can help reduce harmful greenhouse gases and change how people travel.
In 2018, North Carolina Governor Roy Cooper issued Executive Order 80 as a commitment by the state to address a changing climate and transition to a clean-energy economy. Under the order, NCDOT now produces annual resiliency strategy reports that are to “serve as a roadmap to guide resilience awareness, potential policy amendments, practice enhancements and investment decisions in infrastructure.”
Additionally, the department adopted in 2021 its first official resiliency policy to guide future decisions and take active steps to mitigate risks and hazards from people and Mother Nature. The goal was to strengthen the transportation network.
Together, Lauffer said, the reports and the new policy will help the department leverage future grants and be better prepared to respond and recover from natural disasters.
Earlier this year, Cooper announced another initiative, Executive Order 246, which seeks to build on his earlier Executive Order 80. His latest order reaffirms North Carolina’s commitment to transitioning to a clean-energy economy, reducing greenhouse gas emissions, and getting more electric vehicles on the road.
Executive Order 246 also tasks NCDOT with developing a North Carolina Clean Transportation Plan by 2023. The plan’s goals include recommending strategies for how the state may reduce vehicle miles traveled, boost zero-emission vehicle sales and usage, and invest in clean transportation infrastructure.
“We are collaborating with stakeholders to create this plan,” said Joey Hopkins, the agency’s chief operating officer. “We will seek to consider the diverse viewpoints of all stakeholders.”
Embracing New Technologies
While NCDOT is embracing new technologies, the agency’s leadership recognizes that these same technologies present existential challenges for an agency that has relied heavily upon revenue from the gas tax to fund the transportation network. By no longer relying on gas, zero-emission vehicles will reduce harmful air emissions in North Carolina, but will also greatly reduce NCDOT’s largest source of revenue – the gas tax.
About half of the revenue the N.C. Department of Transportation collects for building and maintaining the road network comes from the state gas tax.
The onset of the COVID-19 pandemic, when driving plummeted in the spring of 2020, illustrated just how vulnerable the agency is to gas taxes. The temporary drop in traffic volumes and the curbing of economic activity caused the department to drop below minimum cash balances. As a result, NCDOT was forced to suspend all but essential services for part of 2020.
“We’re seeing rapid changes in our industry,” Hopkins said. “We’re seeing innovations that are extending the driving range for electric vehicles, and making them more affordable.”
That’s why the department created a blue-ribbon panel of experts in finance, policy, and technology from across the state to study the state’s current and future transportation investment needs and strategies. That panel, called the N.C. First Commission, released its recommendations last year.
“We will be working with the state legislature and our governor on long-term strategies to help replace the gas tax revenues we have relied upon,” Boyette said. “If we do this right, North Carolina will be in a stronger position to compete globally for generations to come and continue to provide a high-quality place to live, go to school, work, play and raise a family.”
Ready for Next Storm
Hunter, the former Division 2 engineer, said the decision to relocate the equipment before Hurricane Florence likely saved tens of thousands of dollars in damage to vehicles and equipment that had been relocated to higher ground.
Hunter described the department’s new flood-warning tools as a “game-changer” when preparing for the next hurricane.
“We always know where our trouble spots are in low-lying areas from past storms, but each storm is unique, as Florence powerfully demonstrated,” Hunter said. “Now, we’ll be able to better stage our equipment and prepare for impacts to our road network.”R&B
Andrew Barksdale has been serving as a communications officer for divisions 2, 4 and 6, for the North Carolina Department of Transportation for five years. Andrew is a graduate of Indiana University Bloomington, where he earned a Bachelor of Science degree in Journalism and Political Science. Prior to joining NDOT, he was a reporter for the Fayetteville Observer for 17 years.