By Rosemary Ford and Caitlin Agnew

This article has been edited lightly for length and clarity. 

Flooding has been a problem along scenic Route 1A for years. Regularly used by visitors from across the state and country, the popular Seacoast thoroughfare is subject to more volatile weather and rising tides due to climate change. Plans are underway to shore up its seawalls and ensure Route 1A’s resiliency. On this episode of “The State We’re In,” Melanie Plenda discusses these plans with Department of Transportation Commissioner Bill Cass, Assistant Director of Development Tobey Reynolds, and the agency’s Bureau of Environment administrator, Kevin Nyhan.

Melanie Plenda:

Let's talk about the state of Route 1A. Can you tell us about its problems in recent years?

Bill Cass:

 A lot of Route 1A is protected by a series of stone, shell piles, mortar rubble and masonry walls, between Route 1A and the ocean side. Most of those defenses were built following the blizzard of ’78, so they've been in place for a long time, storm after storm, and over the years they have continued to be impacted. More frequently, we're seeing increasing frequency and intensity of storms. 

So the integrity of the walls, the performance of those walls,  is becoming more and more jeopardized, they're ever more vulnerable to continued deterioration. That is really the concern that we're trying to address. So along with that vulnerability and continued erosion comes more frequent road closures, extended cleanup and things like that as they continue to degrade and not do the job they were originally designed for.

Melanie Plenda:

What role does climate change play in all of this?

Kevin Nyhan:

There's no question that we're experiencing changing environmental conditions on the Seacoast especially. Whether that's high tides or more intense precipitation or even higher frequency of flooding, those things are real, and we're experiencing them. Here at the Bureau of Environment, for every project that we do we undertake a comprehensive and multidisciplinary environmental review of those projects, identifying environmental concerns, evaluating our impacts and looking at alternatives to those impacts. 

I think it’s been in the last several years that sea level rise and the changing environmental conditions have come to the forefront, or certainly things that we evaluate when we're doing those analyses. And understanding how the facilities that we are constructing are compatible with those future conditions is certainly something else that's in the forefront of what we're evaluating. 

To do that, we have a number of tools that we use, whether it's design manuals that reference the most recent rainfall data, and sea level rise scenarios. I think it's fair to say that some of the other tools that we have are working with our partner agencies, the Department of Environmental Services, and the rules that we follow there for environmental issues compel our forward thinking.

Melanie Plenda:

New Hampshire received a $20 million federal grant to make changes to Route 1A. What will those changes entail, and how will this help?

Toby Reynolds:

We're very, very grateful for that award. It's going to help us immensely with this project and moving it forward.

The department's responsible for a number of seawalls along Route 1A, stretching from North Hampton up to Odiorne State Park in Rye. As part of our grant application for the $20 million, we identified nine stone revetment sections that are in need of repair. For the grant, we isolated three of those revetments. We selected those based on past damage  and the frequency of the damage and the number of times that we've had to close 1A as a result, and those three had the highest recurrence times.  All three of those revetments have a total length of about 3,000 feet, so it's pretty significant in the amount of work that we're going to be able to get done with the $20 million.

The reconstruction will entail reconstructing the revetments mostly to the same footprint as they're in today. But, like the commissioner said, the designs that were done in the ‘70s and the amount of damage that the walls have received over time — the maintenance of those walls were just not holding up to the intensity of the storms that we're seeing today. 

The new designs will take into account the intensity of the storms with sea level rise, and the stone size, especially on the ocean side will be sized to withstand that wave action or the intensity of the winds that we're seeing today. What this will do for us is it will greatly reduce the cleanup associated with the seawall, the stone revetments, after the storm. During the storm, we still will expect to see splash over the walls, we will still expect to see the east side or the marsh side continue to rise in flood portions during storms. But once the storm is over, once the high tide recedes, we would expect the flooding to dissipate more rapidly. We would expect very minimal cleanup from these reconstructed stone revetment walls, and therefore the closures would be much less and our cleanup effort would be much less as well.

Melanie Plenda:

What will the construction and timeline look like for this project? 

Toby Reynolds:

We would like to do it as soon as possible, but there are a number of steps that we have to go through to get projects like this underway. Our current schedule puts the start of construction around early spring of 2027. The reason for this is mostly related to the process of contracting with experts that do this design work. Also, completing the design, permitting and also making sure we have the time to do public outreach.

Once construction starts, we anticipate the heaviest of the construction is going to be in the off-peak times — try to work outside of June, July and August. But there is a lot of work here to do. It's going to take time to do it, so we're also looking for opportunities when we can complete work during those summer months, but also reducing the impact to the motorists because we know that that time of year is when most people like to drive up and down and enjoy the coast. 

Melanie Plenda:

What impact will this project have on state and tourism in the region? 

Bill Cass:

It should have a very positive impact. Right now, when we have these big storms and damage to the walls it impacts traffic on Route 1A. Route 1A is a primary north-south area servicing the beaches and coastal communities. It's important to the tourist activity, it's important to the local businesses, and it's important to emergency response through there. So when we have these more frequent storms that take longer to recover from it definitely affects all of those elements. 

These projects will make these revetments more stable, more resilient, so that when there is this splashover, when there are storms, they won't have damaged the road and we won't have the extended recovery times that impacts tourism, traffic access to the communities and emergency responses.

Melanie Plenda:

How flexible is this plan? Will it address future environmental issues?

Kevin Nyhan:

I would say it does. Working with our partners, we all recognize that the things we do today need to survive and be effective into the future. So when we look at the projects that we're building, we’re looking at what the impacts are on the ground today and how we can mitigate those and how we can minimize them. But certainly now, and on the Seacoast especially, we’re having to make the point that even though we have a little bit more impact today it's for the benefit of the future. 

Melanie Plenda:

Are there other areas of concern on the Seacoast, and is the state looking at any similar projects on the Seacoast or other areas of the state?

Kevin Nyhan:

Regardless of where our project is, we're doing the same type of environmental review. We're looking at wetlands and water quality, endangered species and things of that nature. Certainly on the Seacoast, we've had sea level rise and tidal influence. We’re not going to experience that on the western side of the state, but precipitation, management of water quality, minimizing impacts on endangered species and being sensitive to our cultural sites are things that we do for all projects. The analysis is pretty similar, regardless of where we are.

Melanie Plenda:

Good luck. Department of Transportation Commissioner Bill Cass, Assistant Director of Development Tobey Reynolds and Bureau of Environment Administrator Kevin Nyhan — thank you all so much for joining us today.

“The State We’re In” is a weekly digital public affairs show produced by NH PBS and The Marlin Fitzwater Center for Communications. It is shared with partners in the Granite State News Collaborative, of which both organizations are members.

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