Survey measurements have been made at nine sites (shown below) along the southern shoreline of Rhode Island over the past few decades, ranging from Misquamicut Beach to South Kingstown Town Beach. Today, eight beaches are regularly surveyed (all below except Cha-EZ).
How are RI beaches changing over decades?
All of the surveyed beaches show significant changes over past decades. The Moonstone and Green Hill sites are eroding most rapidly while others have exhibited more moderate to minimal net erosion. However, East Beach 1 has experienced some net beach accretion since 1963. Use the graphing tool below to explore the beach profile data over time at the nine beach survey sites. Select beach site, month, and years, and 10 profiles will be shown over the period.
How are RI beaches seasonally or from storms?
Regular visitors to beaches understand that seasonal changes to beach morphology are expected due to erosion and deposition. Winter storms typially move sediments offshore, and during the summer period, fairweather waves help carry sand back onto a beach. This cycle is governed by the natural physics of the ocean and climate patterns affecting the Ocean State. Strong hurricanes or other storms bring powerful waves and currents that can dramatically alter the beach shape and even erode the adjacent dune and infrastructure. To evaluate changes over a 12-month period, select a site location below and choose the year and starting month. For example, try looking at 2012 -- the year of Hurricane Sandy -- and you will see major erosion on many RI beaches.
How have beach surveys site changed over time?
Because of chronic erosion, the beach has moved landward at several study sites over time, so the beach surveyed today is in a different location than the past. Also, we now use an easier method to map the beach profile -- read about it in the Methods.
Below is another way to view the beach profile data over time. In the graph below, the x-axis is the distance relative to a fixed point on land, and the y-axis is time (year). Each horizontal line on the graph represents the measurement of a single beach profile relative to the same fixed point. The color along the line indicates the elevation (see scale). So, over time (looking down the y-axis) a shift of the profile position to the left indicates that the beach profile has moved landward. So, a beach elevation profile today might look the same as the past, but in fact, its position may have shifted landward due erosion.
How much sediment erosion has occured?
If we look at a beach from above in aerial photos over time, we can measure the landward movement of the shoreline. However, if we want to know how much sediment has eroded from a coastline we need to know how its topography (elevations) have changed. So, to measure sediment erosion (or accretion), the beach volume is calculated by summing up the area under the beach profile. To see how the beach volume has changed over time any of the survey sites, use the graphing tool below.
Does the slope of a beach change over time?
Yes! The slope of a beach is related to the sediment that makes up a beach as well as the waves, tides and recent storm activity at the beach. Below is a plot of the calculated beach slope over time for the selected beach. You can select another beach or inspect the beach slope on a specific date. Note, some beach surveys did not extend low enough on the beach, so the slope measurement may be inaccurate.