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  • Writer's pictureEmerson Goodrich

What We Stand to Lose: Quantifying Dune Loss and Coastal Erosion in Southern Maine

Emerson Goodrich, Data and Planning Fellow for GPCOG and the Town of Scarborough, underscores the role of dune systems in coastal protection and resilience and highlights the importance of quantifying the impacts of climate change in coastal communities. 

 

The January 10th and 13th storms, which brought coastal storm surges, record-breaking water levels, and damaging heavy winds, devastated Maine’s coastline. I had just moved to Maine and begun to serve with the Town of Scarborough. My initial tour of the Town became part damage assessment as well. Scarborough’s coastal neighborhoods, such as Higgins Beach, took the brunt of the storm’s impacts. Sections of the sidewalk had completely washed out, and residents were already repairing failed seawalls along the beach.

 

Damage to the sidewalk at Higgins Beach, January 15th, 2024.

 

These storms, coupled with the looming consequences of a rapidly changing climate, call into question traditional coastal management approaches. Management practices, such as the construction of seawalls, while intended to resist extreme weather events, often come at the expense of dune systems' resilience and long-term sustainability (Feagin et al., 2015). The escalating costs and ineffectiveness of maintaining grey infrastructure in the face of harsher and more frequent storms underscore the value of preserving natural systems and embracing low-cost, nature-based solutions (read more about nature-based solutions in my colleague Oona’s post: The Power of Wetlands: An Overview of Current Nature Based Solution Projects in Maine).

 

Coastal areas, which make up approximately 25 percent of the continental U.S., are increasingly vulnerable to the impacts of climate change. The relentless pace of coastal development, increasing by over 12 percent between 1996 and 2021 (NOAA Office for Coastal Management), magnifies the strain on critical natural resources and systems that are already disproportionately shouldering the burden of climate change.

 

Among highly vulnerable natural systems are coastal dunes systems, which serve as natural protection against severe weather events. Dunes are a coast’s first line of defense against a storm surge and function as both a physical barrier and a substrate for vegetation. Scarborough is home to numerous dune systems, but unlike the Town’s acres of marshland, only a few feet of dunes protect Scarborough’s coastal communities.

 

The State of Maine’s Beaches report, conducted by the Maine Geological Survey in 2022, provides a comprehensive survey and mapping of dune changes among other data points in Maine. This longitudinal data, beginning in 2007, allows for the identification of patterns and the monitoring of beach health and resilience over time.

 

Dunes at Western Beach and East Grand Beach reported highly positive growth rates, upwards of 3 feet per year. The northern end of Ferry Beach and the northeastern portion of Scarborough remained slightly accretive as well, while their southeastern and southwestern counterparts both recorded erosion corresponding with possible effects from seawalls. Pine Point Beach also recorded varying degrees of dune loss depending on the area. Higgins Beach has seen pronounced dune loss along nearly the entire natural beach between 2007-2021, with some areas eroding up to 8 feet per year in the most recent year. Except for Higgins Beach and Western Beach, average dune growth in Scarborough’s beaches is trending towards less dune accretion and more dune erosion (Slovinsky et al., 2022).

 

An additional beach profile conducted at Higgins Beach underscores the impact of human infrastructure, with the dunes located near seawalls exhibiting minimal dune volumes and susceptibility to disappearance during seasonal fluctuations (Slovinsky et al., 2022).

 

While the report does not capture the impact of the January storms on Scarborough’s dune systems, recorded patterns of dune presence, loss, and fluctuation, along with anecdotal evidence and observations, demonstrate why Higgins Beach was hit so hard. Coastal Scarborough communities with more robust and contiguous dune systems, such as those along Pine Point Beach, experienced less damage to personal property when compared with those along Higgins Beach, where protective dunes are essentially nonexistent.

 

Despite the ability of dunes to protect coastal infrastructure from typical weather events, as well as increasingly common atypical weather events, human infrastructure has severely limited the ability of dynamic dune systems to adapt (Lansu et al., 2024). Data from the January storms reinforce the role roads and dune paths play in further limiting and harming already compromised dunes during storm events. Both act as runways for flood water leading to increased detrimental overwash into communities by extension accelerating the rate of dune degradation (City of Saco, 2024).

 

Looking ahead, data predicting dune loss must also be contextualized within the larger issues of sea level rise and coastal erosion. Without intervention, Higgins Beach and countless other coastal communities face uncertain and unrecognizable futures under almost any sea level rise scenario.

 

Figure 1: Intermediate Sea Level Rise Scenario at Higgins Beach, FEMA Coastal Erosion Hazard Map, 2024.

 

Figure 2: High Sea Level Rise Scenario at Higgins Beach, FEMA Coastal Erosion Hazard Map, 2024.

 

Efforts to mitigate damage to existing dune systems are gaining momentum on both large and small scales. At the federal level, the government’s investments in shore stabilization are shifting towards non-structural, nature-based solutions, such as beach nourishment. Coastal restoration may also gain traction as a cost-effective solution for many communities. Returning coastal lands to their undeveloped states increases coastal resilience, sequesters carbon and other pollutants, and restores native habitats (U.S. Climate Toolkit). At the community level, dune restoration and protection tactics are most effective when implemented collaboratively. Projects such as beach nourishment and beach scraping, can be taken up by private property owners to restore and fortify dunes. Limiting individual footpaths, introducing zig-zag paths or mats, and closing off beachfront streets with temporary barriers can minimize floodways and prevent dune erosion during storm events (City of Saco, 2024).

 

Figure 3: “Consequences of coastal squeeze in current and future conditions.” Lansu et al., (2024)

 

Quantifying the potential losses facing coastal communities in the coming decades underscores the need to integrate natural protection and restoration in planning policies and plans. Between historical degradation from human infrastructure and the predicted impacts of climate change, we stand to lose a mappable, but truly immeasurably resource in our coastal ecosystems.

 


City of Saco (2024), 2024 Saco Bay Symposium, https://www.youtube.com/watch?v=hQtmKpfGx24&t=853s 

 

 

Lansu, E.M., Reijers, V.C., Höfer, S. et al. (2024), A global analysis of how human infrastructure squeezes sandy coasts. Nat Commun 15, 432. https://doi.org/10.1038/s41467-023-44659-0 

 

NOAA Office for Coastal Management (n.d.), Coastal Change Analysis Program, Regional Land Cover 1996 to 2021, https://coast.noaa.gov/digitalcoast/data/ccapregional.html

 

Slovinsky, Peter A., Dickson, Stephen M., and Meenan, Natalie R. (2022), State of Maine's Beaches in 2022: Maine Geological Survey, Maine Geological Survey Publications. 618. https://digitalmaine.com/mgs_publications/618 

 

U.S. Climate Resilience Toolkit (n.d.), Coastal Erosion, https://toolkit.climate.gov/topics/coastal-flood-risk/coastal-erosion 




About Emerson

Emerson is from San Francisco but split her time across Northern California while growing up. She recently graduated from Brown University where she received bachelor’s degrees in Public Health and International & Public Affairs and served as a captain on the varsity rugby team. Emerson cultivated an interest in planning through work on the Urban Transition Historical GIS Project, mapping patterns of neighborhood change, and with BAE Urban Economics, focusing on community economic development. As a Resilience Fellow, Emerson is eager to explore the intersection of community health, resilience planning, and placemaking while serving at both the municipal and regional level. Emerson looks forward to camping, snowboarding, trail running, walking on the beach, and generally enjoying time outdoors as she gets to know Maine.

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