High Tide Causes Flooding in Hampton Beach During Spring Nor’easter

With climate change bringing rising sea levels and more frequent intense storms, coastal communities like Hampton Beach, New Hampshire are particularly vulnerable to flooding events. A recent nor’easter demonstrated this risk as heavy rain and strong winds coincided with unusually high tides, overwhelming the area’s flood defenses. As an environmental engineer, I will explore the causes and impacts of this flooding, as well as possible mitigation strategies to better protect Hampton Beach in future storms.

Storm Surge Meets King Tide

The nor’easter that struck in early March produced severe beach erosion and widespread flooding across Hampton Beach. Sustained winds of 50 mph pushed ocean water inland, with wave heights reaching 10 feet in some areas. At the same time, astronomical tides known as “king tides” were occurring—winter tides that are among the highest of the year. The combination of storm surge pushing from offshore and higher-than-normal tides limited the ability of the existing seawall and berm to hold back floodwaters. This “coastal squeeze” overwhelmed normal drainage channels, inundating homes, roads, and businesses with over 2 feet of water in some locations.

High Tide Triggers

Several factors contributed to the record-breaking tidal levels during the nor’easter. The moon was close to perigee, its closest point to Earth in its elliptical orbit. This gravitational effect amplifies tide ranges. In addition, onshore winds from the storm piled up water against the coast. Barometric pressure changes associated with the low-pressure system also influenced tide heights. All of these tidal triggering mechanisms maximized water levels, overwhelming existing flood defenses designed for more typical conditions.

Environmental Impacts of Flooding in Hampton Beach

The flooding had widespread environmental impacts on the coastal landscape and habitat. Beachfront homes and businesses sustained water damage that will require costly repairs. Roads and infrastructure like pipes and electrical lines also incurred damage, disrupting normal functions. Perhaps more significantly for the long-term health of the coastal ecosystem, the nor’easter exacerbated ongoing beach erosion issues. Pounding surf and storm surge carved away large volumes of sand, narrowing the beach in critical dune areas that protect inland properties. Loss of dunes and beach width diminishes natural buffering against future flood events. Overwashed sediments carried inland by floodwaters also smothered dune vegetation important for stabilizing the foredunes. Replenishing and restoring dune habitats will be a priority to improve flood resiliency.

Mitigating Erosion

Several approaches can help mitigate erosion and build coastal resilience. “Soft” solutions like dune restoration, beach nourishment, and the strategic placement of natural wooden groins will boost the width and integrity of the dune system over time. Nourishing the beach by trucking in new high-quality sand and grading it to natural contours replaces sand lost to erosion. Planting dune grasses and shrubs like American beachgrass and bayberry aids in trapping windblown sand, ultimately raising dune elevations. “Hard” structures like seawalls, revetments, and bulkheads should only be considered after exploring natural alternatives, as they disrupt sediment transport and long-term beach sustainability. A combination of soft and hard solutions tailored to Hampton Beach’s unique conditions will provide the best defense.

Flood Risk Management

Effectively managing future flood risk also requires accounting for climate change impacts like accelerated sea level rise. Projections estimate 10-30 inches of rise for New Hampshire’s seacoast by 2100, increasing the frequency and severity of flooding even in moderate storms. Maintaining and elevating existing seawalls may no longer suffice on their own. Regional planners should study “green infrastructure” solutions as part of an integrated coastal protection strategy. Low-impact development (LID) techniques like bioswales, rain gardens, and permeable pavement can help absorb and slow stormwater runoff. Floodable storage areas, elevated roads, and fortified drainage channels improve drainage of localized flooding. Strategically, managed retreat from the most hazard-prone areas should also be considered over the long term.

Trends in Sea Level Rise

Recent tide gauge data confirms New Hampshire is experiencing sea level rise at a rate significantly higher than the global average of roughly 8 inches per century. Portsmouth clocked a rise of 1.8 inches per decade between 2006-2015 according to National Oceanic and Atmospheric Administration (NOAA) measurements. While local land subsidence may exaggerate these trends somewhat, climate-driven ocean expansion and glacial melting are undoubtedly major drivers. Analyzing these patterns will help coastal managers forecast future scenarios and adapt accordingly. Low-lying areas may eventually require more extensive “climate-smart” solutions such as reversible barriers across inlets or land acquisition in expected flood zones.

Community Adaptation & Resilience

On the community level, Hampton Beach can take steps to improve overall adaptation and resilience to increased flooding risks. Assessments should identify critical infrastructure and vulnerable populations to focus protection strategies. Initiating regular beach profile monitoring and developing a comprehensive adaptation plan based on climate and hazard projections will pave the way for targeted capital projects. Updating zoning and planning regulations that restrict rebuilding in hazard-prone areas aims to avoid entanglement in costly regulatory battles after future disasters. Promoting transition to flood-resistant buildings through programs like “elevate or relocate” financial incentives also empowers individuals. Consistent public education on issues like sea level rise and citizen involvement in resilience planning strengthens community support for adaptive measures. Overall, a coordinated, multi-level approach will best serve Hampton Beach’s long-term sustainability.