Feature image: Route 1 Spruce Creek causeway during high tide with inundated culvert. Photo credit: CMA Engineers, Inc.
Last updated March 24, 2026.
Understanding the Challenge
In January 2026, the Piscataqua Region Estuaries Partnership (PREP) joined the Town of Kittery and regional partners to begin addressing a growing challenge: flooding along two important roadway crossings, Whipple Road near Gate 2 of the Portsmouth Naval Shipyard (PNSY) and the Route 1 crossing at Spruce Creek. This workshop was part of Climate Ready Kittery, a two-year project led by Southern Maine Planning and Development Commission (SMPDC) and supported by the Wells National Estuarine Research Reserve (WNERR) and PREP.
Climate Ready Kittery brings together local, state, and federal partners to align priorities for adapting infrastructure while balancing flood risk and supporting public safety, transportation access, environmental resources, national defense operations, and the local economy. The workshop included participants from the Town of Kittery, state and federal agencies, engineers, and technical experts from CMA Engineers and Streamworks, consulting firms specializing in civil and environmental engineering with experience in tidal modeling and coastal infrastructure planning.
This level of coordination on coastal infrastructure planning is increasingly necessary in Kittery. Coastal storms do not just impact the beach shorelines, they disrupt daily movement through town. Spruce Creek, a tidal tributary that bisects Kittery and separates it from Kittery Point, flows beneath Route 1 and I-95 and drains a 9.5-square-mile watershed, 90 percent of which lies within town boundaries. As tides rise and stormwater backs up through the system, flooding and road closures are becoming more common. High-traffic routes near Gate 2 of the Portsmouth Naval Shipyard and the Route 1 bridge at Spruce Creek share the same challenge: they are heavily used connections where flooding is becoming more frequent.
This work is supported by federal funding through the National Fish and Wildlife Foundation’s National Coastal Resilience Fund* and made possible through the shared commitment of local, state, and federal partners—including the Piscataqua Region Estuaries Partnership—who have invested staff time and collaboration to advance this effort. To begin addressing these challenges, project partners focused on building shared understanding before turning to engineering solutions.
*The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government or the National Fish and Wildlife Foundation and its funding sources. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government, or the National Fish and Wildlife Foundation or its funding sources.
The Climate Ready Kittery Collaborative Advisory Group met in January 2026 for an in-depth workshop focused on two important crossings in Kittery: Whipple Road at Gate 2 of the Portsmouth Naval Shipyard and the Route 1 crossing at Spruce Creek. Photo by PREP.
Building Agreement Before Design
When a project touches many parts of a community, working toward consensus and balancing different needs is essential when many groups are affected. Rather than beginning with engineering solutions, the workshop focused first on building agreement around shared objectives and acceptable levels of flood risk.
The process drew from CoastWise, a voluntary framework that supports communities in making informed decisions about safe, cost-effective, ecologically supportive, and climate-resilient tidal crossings. By adapting this approach, participants prioritized goals for each site and evaluated flood risk tolerance based on public safety, infrastructure resilience, economic impacts, and projected sea level rise. Through facilitated discussion and consensus-building exercises, the group worked toward agreement on the level of risk each crossing represents.
Bringing local, state, and federal decision-makers together at the outset is a unique and important step toward delivering solutions that are technically sound, fundable, and broadly supported. The team is documenting this effort as a case study for how our region can collaborate effectively as it faces more frequent flooding, stronger coastal storms, and rising seas.
Flooding at Whipple Road in January 2024. Photo credit: U.S. Navy photo courtesy of Naval Facilities engineering Systems Command (NAVFAC).
Exploring Strategies for Whipple Road and PNSY Gate 2
Whipple Road serves as an access point to the Portsmouth Naval Shipyard and connects key parts of Kittery. It supports shipyard employees, town residents, emergency services, utilities, and local businesses. When this roadway floods, it can affect travel, emergency access, and daily activity across town.
What We Heard
Across agencies, there was strong agreement on several priorities:
- Minimize flooding impacts to infrastructure and adjacent property owners
- Maintain emergency access
- Support multimodal transportation (pedestrian and bicycle access)
- When feasible, take a phased, scalable approach
- Keep cost and constructability in focus
Workshop participants acknowledged Whipple Road is already at risk of flooding during severe storms, and that raising the roadway would be the most effective adaptation strategy. However, underlying clay soils and dense utility infrastructure make this technically complex and costly. Subsurface improvements would likely be needed rather than simply adding fill.
There was also a shared desire to “get it right” the first time. If the road is raised, it may present opportunities to address existing traffic and safety concerns near Gate 2, including signalization and turning movements.
Assessing Flood Risk and Consequences for Whipple Road
To help participants evaluate each site, the project team developed a Coastal Flood Risk Consequences Assessment Framework, adapted from the CoastWise approach. The framework asks participants to consider a range of potential consequences such as impacts to infrastructure, emergency response, transportation access, utilities, and economic activity and rank each on a scale from low to very high impact. This structured exercise helped the group evaluate not just the likelihood of flooding, but the real-world consequences if flooding occurs.
Recent storms, including those in December 2023 and January 2024, highlighted how disruptive flooding can be. Participants discussed:
- Potential sewer and stormwater failures
- Impacts to emergency response times
- Regional ripple effects if Route 1 or I-95 are also compromised
- Delays to shipyard operations and workforce mobility
Through this assessment process, the group determined that Whipple Road falls within the High to Very High risk consequence category, reinforcing the need for thoughtful and timely action.
Nick Messina from CMA Engineers, Inc, shares site assessment results during the Collaborative Advisory Group Site walk in July 2025. Photo credit (left): SMPDC. Photo (right) by PREP.
Exploring Strategies for Route 1 at Spruce Creek
The Route 1 tidal crossing at Spruce Creek presents a different and in some ways more complex, challenge. Unlike Whipple Road, this location offers greater opportunities for environmental restoration, improved water quality, and habitat health. It also serves as a major regional transportation corridor and emergency backup to I-95.
Key Themes from the Discussion
- Maintain uninterrupted access on Route 1—closure is widely viewed as unacceptable.
- Address erosion and embankment instability
- Improve stormwater treatment and water quality
- Improve tidal exchange for wetland health
- Consider fish passage and marsh migration
Spruce Creek drains into the greater Piscataqua River watershed and is subject to water quality requirements under the town’s MS4 permit (Municipal Separate Storm Sewer System), which requires communities to manage stormwater runoff from streets, parking lots, and drainage systems so polluted rainwater does not flow untreated into local waterways.
At the Route 1 crossing, participants emphasized that improving water quality and supporting habitat restoration are strong community priorities.
Project engineers noted that while the existing culvert currently handles tidal exchange, it may constrain ecological processes like fish passage and marsh health. Options discussed included modifying or removing an existing upstream weir, replacing the existing culvert with a larger structure, or integrating green stormwater infrastructure such as bioswales and subsurface filters.
Trade-offs were carefully considered. Increasing tidal exchange could influence upstream flooding patterns,and raising the road could have impacts for nearby properties.
Assessing Flood Risk and Consequences for Route 1
Using the same Coastal Flood Risk Consequences Assessment Framework, participants evaluated how flooding at the Route 1 crossing could affect transportation, infrastructure, emergency response, and the surrounding community. After discussing these factors, participants voted on the overall level of risk consequences using a scale from low to very high.
The voting exercise revealed an even split between “High” and “Very High” risk consequences.
Participants pointed to several factors influencing their assessment, including:
- Increasing frequency of flooding events
- Potential scour and structural risks to the causeway
- The relationship between Route 1 and I-95 resilience
- Utility vulnerabilities beneath the roadway
- Impacts to sidewalks and ADA (Americans with Disabilities Act) access
While the group did not land on a single category, the discussion clearly indicated that Route 1 is a high-priority regional asset deserving serious resilience planning.
Workshop participant sit around a room raising hands as they prioritize goals for each site and evaluated flood-risk tolerance based on public safety, infrastructure resilience, economic impacts, and projected sea-level rise. Photo credit: Laura Berry of SMPDC.
A New Model of Collaboration
What makes this effort unique is not just the engineering complexity, it’s the governance model.
Representatives from the Town of Kittery, Kittery Water District, MaineDOT, and the Portsmouth Naval Shipyard worked with the Project Team to weigh trade-offs, discuss risk tolerance, and identify shared priorities for each site.
In many infrastructure projects, agencies and stakeholders weigh in at different stages of planning. In this case, local, state, and federal partners worked together early to discuss objectives, constraints, and acceptable levels of risk before design concepts are developed.
This approach helps ensure that future strategies reflect a shared understanding of both the challenges and priorities. It also allows partners to explore different implementation strategies—whether phased improvements or larger, one-time investments—depending what makes the most sense for each location.
For PREP and its partners, this collaborative model offers an important example of how communities, agencies, and technical experts can work together to plan for the complex challenges of coastal flooding and climate change.
What Happens Next
The workshop concluded with strong endorsement of the design objectives for both roadways, providing a clear foundation for the next phase of work.
In the months ahead, the project team will advance conceptual design options, evaluate implementation strategies, and continue coordination across agencies. Importantly, there will be a public-facing phase where Kittery community members will have the opportunity to review concepts, ask questions, and provide input.
Flooding and coastal change are not distant possibilities; they are already affecting Kittery’s roads, neighborhoods, and natural systems. Whipple Road and Route 1 at Spruce Creek play an important role in public safety, local jobs, and environmental health in our region. Addressing them thoughtfully and collaboratively is essential. This workshop marked an important step toward addressing flooding challenges along two key roadways in Kittery, with collaboration at the center.
Stay tuned for additional opportunities to engage as this work moves forward.
To get connected to the project, please contact Annie Cox at PREP (Anne.Cox@unh.edu) or the project lead, Laura Berry at Southern Maine Planning & Development Commission (lberry@smpdc.org).