Shoreline Monitoring

Beaches in the CNMI are important coastal resources that connect visitors and residents to the ocean. These important ecosystems also have high recreational, aesthetic, economic, subsistence, and cultural value.

Their width and shape are naturally ever-changing with how sediment moves within our coast and ocean. However, swells and storms drive high energy waves into the shore and increase shoreline movement, which concerns beach loss. Beaches also provide a natural defense from waves. For certain beaches, erosion threatens nearby infrastructure close to the waterline and endangers users with hazardous footing. Storm-driven erosion is the primary cause of significant beach loss in the CNMI.

The Hyatt Regency to Crowne Plaza Resort is an actively eroding site. Each powerful storm has chipped away the berm, losing area that was once road and concessionaire space.

As sandy beach is lost, the vulnerability of beach front communities and infrastructure to storm surge and coastal erosion increase. Sea level rise is expected to cause retreat of coastlines worldwide.

To understand and document these interactions, DCRM’s Shoreline Monitoring Program studies beach sites to better inform coastal planning and development. Our team conducts field surveys at beach sites on Saipan to capture shoreline change.

The background is a vegetated sandy beach north of Sugar Dock, where a boat is docked. On the left is Ross Arriola pointing next to the mounted Berger Level. Thomas Benavente is holding the rod level in the middle. Kiana is looking towards Thomas with the record book in hand.
2021 DCRM Summer Interns, Ross Arriola (left), Thomas Benavente (middle), and Kiana Camacho (right) are surveying the accreted beach fronting the Tasi Homes in July 2021.
The eroding berm is evident here at the site between Crowne Plaza and Hyatt, which reduced to sudden drop from the backshore and the nearshore environment. The erosion chips away at the berm and moves the beach back each storm. Photo captured in April 2022.





Watch videos to learn about the importance of Shoreline Monitoring for local coastal management mission.

Shoreline Monitoring Importance to DCRM’s Mission

How DCRM Monitors Beaches

2022 Shoreline monitoring program story map

Checking out our interactive Story Map developed by 2022 DCRM summer interns.

shoreline Trends map

View the “Shoreline Trends” of the Climate Impact Viewer to see which sites have been eroding, accreting, exhibiting stability, or undetermined, and more!


Click on any of the thumbnails below to view the detailed beach profile interpretations of the team for Saipan, Tinian, and Rota.

DCRM’s Beach Profile reports interpret beach profile information produced from our on-the-ground beach surveys. Beach profiles show how the area is growing, losing, or staying the same throughout time.


Cover Photo of the Shoreline Monitoring Beach Profile report: Saipan and Managaha which shows the erosion scarp of the retreating beach at Hyatt and Crowne Plaza shoreline site
The Shoreline Monitoring Beach Profile Report: Saipan and Mañagaha presents data collected using the Berger and Total Station surveying approaches to inform shoreline change on Saipan and Mañagaha.


The Shoreline Monitoring Beach Profile Report: Tinian and Rota presents data collected using the Berger and Total Station surveying approaches to inform shoreline change on Tinian and Rota.
The Shoreline Monitoring Beach Profile Report: Tinian and Rota presents data collected using the Berger and Total Station surveying approaches to inform shoreline change on Tinian and Rota.


beach profile activity

Beach Profile Activity is a hands-on learning activity developed by the team for educators. Educators can bring a simplified and affordable version of our field surveying procedure in their classrooms.

Students will gain hands-on experience on the importance of sandy shoreline and conceptualize how climate change impacts erosion. Available for download here.

Other local studies involving our shorelines are found on the Shoreline Publications page.


about the program

Since 2016, DCRM’s Shoreline Monitoring program surveys 17 beaches on Saipan, 9 beach transects on Mañagaha, 2 beaches on Tinian, and 4 beaches on Rota.

The team uses the Berger surveying method to identify, measure, and track changes within these sites. This data is developed into beach profiles for comparison. Through taking bi-annually beach profiles all of our target sites, we aim to understand our islands’ shoreline dynamics and report our findings yearly for data-driven decision making.

Our team comprises of DCRM staff, student interns, and volunteers. We acknowledge the notable contribution of NMC and DCRM Summer interns throughout the years to collect field data necessary for beach profiles and analysis.

2020 Summer Interns – (from left to right) Britney Espinosa, Lance Tudela, and Marvin Sablan, are posing with the Berger Level surveying equipment with Coastal Planner Mary Fem Urena at Wing Beach.
2021 Summer Interns – (from left to right) Kianna Camacho, Thomas Benavente, and Ross Arriola, are posing with the Berger Level surveying equipment at Kilili Beach.
2022 Summer Interns – (from left to right) Andrea Roberto, Catherine Calma, and Jaden Villacrusis, are posing with the Berger Level surveying equipment at Wing Beach.
Four people in the picture with the background of the Jeffrey's Beach rocky shoreline and ocean
2023 Summer Interns – (from left to right) Madison Sablan, Samantha Liske-Clark, Mary Fem Urena (Coastal Planner), and Tamisha Sablan posing at Jeffrey’s Beach.








Contact us

We welcome requests for educational presentations or any questions regarding the program and its products.

Please contact the Shoreline Monitoring Program coordinator, Mary Fem Urena, at or call 670-664-8324.


Terms on this page:

Accretion – The gradual addition of land by deposition of water-borne sediment

Berm – The nearly horizontal portion of the beach or backshore formed by the deposit of materials by wave action. Some beaches have no berms. In the CNMI, the berm is a vertical drop.

Beach Profile – The cross-sectional shape of a beach plotted perpendicular to the shoreline

Berger Level – The nearly horizontal portion of the beach or backshore formed by the deposit of materials by wave action. (In the CNMI, the berm is a vertical drop.)

Coastal Hazards – Phenomena that threaten structures, property, and the environment under extreme weather and water conditions

Coastal Planning – Planning process used to create informed management decisions for zoned coastal area. In the CNMI, all of Saipan, Tinian, and Rota are within the coastal zone. 

Erosion – The wearing away of land and the removal of beach (or dune) sediments by wave action, tidal currents, drainage, or high winds

Headstake – The starting point of a transect. Usually marked on a tree or fixed point in paint

Rod Level – Used with a leveling instrument to determine the difference in height between points

Storm Surge – Abnormal rise in seawater level during a storm, measured as the height of the water above the normal predicted astronomical tide

Transect – A straight line or narrow section across the earth’s surface along which observations are made or measurements are taken

Vulnerability – The likelihood of people, property, industry, resources, ecosystems, or historical buildings and artifacts to coastal hazard impacts, such as shoreline erosion