Coastal Erosion Mitigation on Nantucket

Sponsor: The Nantucket Coastal Conservancy and The Nantucket Civil League
Sponsor Liaison: D.Anne Atherton, Burton (Spruce) Balkind, and Peter Morrison
Student Team: Thomas Cox, Michael Sterk, Peter Tzanetos, and Ryan Waters
Abstract: The goal of this project was to evaluate the use of various photo capturing technologies to document coastal land, analyze coastal erosion, and develop erosion mitigation proposals for selected public locations to add to Nantucket’s Coastal Resilience Plan. To accomplish this, we utilized handheld photography, drone photography, and photogrammetry to document several public locations on Nantucket with high erosion rates. We used this information to qualitatively identify changes in the degree of erosion evident, compare the use of the different photo capturing technologies, and create plans for erosion mitigation at each site, including vegetation, sand fencing, and managed retreat.

Report: Coastal Erosion Mitigation on Nantucket Final IQP

Presentation: Coastal Erosion Mitigation on Nantucket Presentation

Executive Summary


The island of Nantucket is a result of a glacial moraine, a collection of sediment left behind as a result of glacial movements, that was built upon by tidal action (Hoff, 2021). This geological makeup creates an environment that is much more susceptible to erosion than landmasses with a base of bedrock. With the threat of losing land, houses, business, and government buildings, mitigating coastal erosion is an important issue for the island community.


Erosion Control Methods on Nantucket

Several erosion control methods are currently being used on Nantucket, including sand fencing, beach nourishment, vegetation, and retreating. Sand fencing, wooden fence posts connected by wire, can be installed on a beach to capture windblown sand and build dunes. Beach nourishment is the process of importing sand to be deposited on a beach. Vegetation, such as the American Beachgrass native to Massachusetts, can be planted on beaches to stabilize dunes through their roots and catch windblown sand. Finally, retreating is the process of buildings being relocated to areas further away from coastlines to preserve both the structure and shoreline.

Technologies Used to Document Erosion

The most common and favorable way to document erosion is through forms of photography, including handheld photography, drone photography, and photogrammetry. Handheld photography provides a close-up view of the photos subject and is usually the highest quality image one can capture. Drone photography is utilized to take aerial photos of subjects from a distance, providing a view that is farther and higher than handheld photography can capture. Photogrammetry is the process of using specialized software to analyze a set of successive photographs taken from a single camera to recreate a 3D representation of the photos’ subject. The representation, called a point cloud, is made up of discrete colored squares or circles to give the illusion of a 3D object. Figure 1 (following page) showcases how when zoomed out a point cloud appears like a 3D object, but zoomed in reveals the individual element.

Examples of Erosion at Public Sites on Nantucket

For this project we selected 4 public locations to highlight three methods of documenting erosion. The locations — Dionis Beach, the Madaket Beach parking lot, Cisco Beach, and Codfish Park — were also researched using the Massachusetts Oceanic Resource Information System (MORIS). The Massachusetts Office of Coastal Zone Management has developed the MORIS to allow the public to view and create maps with information on Massachusetts coastal regions. MORIS, created by the Massachusetts Office of Coastal Zone Management, is a catalog of maps created by the public and the Commonwealth of Massachusetts. This set of maps provides information and imaging of Massachusetts coastal regions.

MORIS also contains historic and current satellite imagery of Nantucket along with built-in measuring tools. This enabled the team to determine erosion rates for the selected areas.

With information from the MORIS system, the research team was able to conclude the following about the historical erosion rates at the four focus areas:

  • Dionis Beach has experienced lower levels of erosion, with an estimated erosion rate of 1.5 feet per year since 1970 (MORIS). This has caused the dunes at Dionis beach to be tall and steep, making them less stable and easier to erode.
  • Madaket Beach has eroded at an estimated rate of 9 feet per year since 1970, which is the highest rate of the four locations we studied (MORIS). This has caused the parking lot to lose the majority of its area, as well as creating a three-foot drop onto the beach from the lot.
  • Cisco Beach has experienced erosion at an estimated rate of 6 ft per year since 1970 (MORIS). This has caused a steeper slope on the beach, as well as creating smaller dunes farther from the high tide line.
  • Codfish Park has eroded at an estimated rate of 4 ft per year since 1970 (MORIS). While the erosion rate is lower than some of the other locations, the bluff receding threatens the properties atop of it.


The goal of the project was to evaluate the use of various photo capturing technologies to document coastal land, analyze coastal erosion, and develop erosion mitigation proposals for selected public locations to add to Nantucket’s Coastal Resilience Plan. To achieve this goal, the following objectives were identified:

  1. Utilize handheld photography, drone photography, and photogrammetry to visually document coastal erosion at specific public locations on Nantucket.
  2. Identify changes in coastal erosion at specific public locations on Nantucket.
  3. Compare the application of handheld photography, drone photography, and photogrammetry for evaluating coastal erosion.
  4. Propose coastal erosion mitigation strategies for specific public locations that build upon existing plans.


Results of Photo Capturing

Through photography and photogrammetry, we were able to document the coastal erosion occurring at Madaket Beach parking lot, Dionis Beach, Codfish Park, Cisco Beach, and Jetties Beach. Documenting the current level of erosion will allow for future comparisons to see whether there has been erosion or accretion over time. Figure 2 displays examples of the drone photography taken of Dionis Beach.

Photogrammetry was completed on Dionis and Jetties Beach by Jacob Tinkhauser. Additionally, an example of Sconset Bluff was utilized for analysis that was previously completed by Tinkhauser on June 11, 2023. Figure 3 displays the photogrammetry point cloud of Dionis Beach. Finally, handheld photography was taken at all four locations while on public land.

The images taken during research, along with measurements taken within MORIS, demonstrate that changes in erosion are evident at Dionis Beach, Madaket Beach parking lot, Cisco Beach, and Codfish Park. Each of these places have suffered severe damage from erosion in recent years.

Comparing Photo Capturing Technologies

The team has concluded that each of the photo capturing technologies compared has an application in visually documenting coastal erosion, and that none were singularly superior to the others. Photogrammetry point clouds are more useful for analyzing changes in elevation as they can be rotated and viewed freely after capturing. Drone photography is more useful for viewing large stretches of land and areas that are not readily accessible on foot. Handheld photography is more useful for close, detailed views of specific examples of coastal erosion. However, all these technologies can be used in conjunction with each other to allow for more diverse imaging of the coastal erosion in an area. All methods should be utilized frequently, capturing new data at least once per year, to allow for use of the latest data in future reviews. In addition, MORIS provides a comprehensive database of satellite imagery that can be used to view current and historic images of beaches, allowing for coastline recession to be measured.


Dionis Beach

At Dionis beach, sand fencing could be used to help build the dunes on the beach, in addition to creating a new, more gradual grade to the slope. It will also help protect the dunes from people and animals climbing on them and disrupting dune stability. Further planting of vegetation can be used to help build the dunes. Planting at the base of the dunes could help regrade the dunes as they accrete sand, as well as making the dunes more stable through their root systems. Fortunately for Dionis, there are few houses directly on the cliff face, so simply monitoring is an option. Some households may have to relocate, but that would be up to the property owner and done in due time. Some of the dunes are quite high on Dionis, making regrading also a viable option. In combination with vegetation, it could lead to a resilient shoreline.

Madaket Beach Parking Lot

The Madaket Beach parking lot is in a state of disrepair and has a steep drop off at the edge of the lot. A significant portion of the parking lot has already been lost. Monitoring the parking lot to determine if it is doing harm to the beach while continuing to utilize the existing space would be the best solution. Relocating the parking lot is also possible, as the town owns land around Madaket Beach that could be used. Sand fencing would help to build up the sand dunes in the area around the parking lot. This would help slow the current erosion in the area and give more time to apply alternative mitigation methods.

Cisco Beach

At Cisco Beach, vegetation could be used to help to slow down the effects of erosion from smaller waves. This would help stabilize the dunes and allow for accretion. Sand fencing would be effective on Cisco Beach as the dunes are not regularly reached by high tide or storms (Massachusetts Office of Coastal Zone Management, 2018). Sand fencing would help to capture sand. Further monitoring of Cisco Beach is recommended to continue to assess erosion rates and risks.

Codfish Park

For Codfish Park, relocating the houses on top of the bluff would ensure that the houses are not in danger of falling over the cliff, as well as being the best way to protect the bluff from further erosion. Using beach nourishment would allow for the cliff to become more stable and make the slope more gradual to help slow erosion. This would also allow the houses and road at the top of the slope more time before they would either be moved or be abandoned. Since almost all other methods are impractical at Codfish Park due to the high bluff, we recommend monitoring the beach to get more data or to see if other mitigation methods become viable in the future.

Recommendations for Further Work

The team recommends that more data is collected using the three photo capturing methods, as well as other methods once they become available. Photo capturing should be completed once a year at minimum to allow for more data for comparison for later studies. Additionally, new erosion mitigation installations should be prioritized at Codfish Park and Madaket Beach.

The threat of coastal erosion will not be eliminated by the results of this project; it is a greater issue that cannot be solved with one study. While this project will give Nantucket a framework to use to mitigate erosion, the issue will never fully go away. It is up to the residents of Nantucket and the federal government to protect this island community and the amazing things it holds.