Marianas Variety

Last updateWed, 27 Sep 2017 12am







    Tuesday, September 26, 2017-11:08:42A.M.






Reef Tips: Shoreline Monitoring

If you have lived in Saipan for a long time, you can see that the shoreline has changed over time.

Back in the day, people could walk far out onto the beach and play volleyball. Now, the beaches are short and you can only walk along the shoreline.

The reason for these shoreline changes is because of strong currents and tropical storms that extract sand back into the ocean (erosion) or push back onto the shore (accretion). Because of these changes, our summer project, under the Division of Coastal Resource Management and the Coral Reef Initiative, was to conduct shoreline monitoring. The purpose of shoreline monitoring is to take measurements of the beaches and compare those measurements with old data to observe any changes in the shoreline. In a similar study, researchers from Texas discovered that after a storm, there was sand dispersal and shoreline movement (Robert A. Morton, James C. Gibeaut, Jeffery G. Paine 1995). With shoreline monitoring, we can detect how much sand eroded or accreted after a typhoon.

My partners and I took measurements of all the western beaches starting from the south of Pak-Pak Beach making our way to the north of Wing Beach and Managaha. We collect data from the shore by using the Berger level method. First, we lay out a rope that measures up to 100 feet, placing it on the starting point and going into the water. Next, we set up the tripod in the middle of the beach and screw on the Berger level onto the tripod. Once the Berger level is secured, we level it so that it will take accurate measurements of the beaches contour. Lastly, one of us holds the 16-foot measuring rod and goes to each of the measuring points while the other takes notes of the difference in elevation. When we survey the shore, we usually measure every 10 feet, taking note of vegetation, berms, wrack line, high waterline, waterline and moats.

After collecting all the measurements, we input the data into the computer and create a line graph that reveals the beaches slope. It will take some time before we can see differences in the data. However, it is important because it will provide insight into the causes of shoreline changes and how fast the beaches are changing. It also allows us to predict how our beaches will look like in the future so that we can protect our shorelines for future generations to use.


Robert A.Morton, James C.Gibeaut, Jeffrey G.Paine. “Meso-scale Transfer of Sand during and after Storms: Implications for Prediction of Shoreline Movement” - ScienceDirect. Marine Geology, 1995. Web. 30 July 2017.

This article is about storms affecting the shoreline by making sands disappear. After a hurricane at Texas Coast, researchers found out that there was sand dispersal and shoreline movement. Although the storms are one of the causes of the shorelines to erode, it can also be the cause of the shorelines to be accreted. The research had also showed that with beach histories, they can find out which beach is predominant to getting more sand. With this study, it allows us to be able to predict the change of shorelines and the change of climates.