Beach grain size determines slope, impacting coastal erosion and safety.
The size of sand grains on a beach affects how steep the beach slope is. A study looked at 181 beaches worldwide and found that as the grain size gets bigger, the beach slope gets steeper. Beaches with less wave energy have gentler slopes. By using a new method to classify wave energy exposure, equations were created to predict beach slope based on grain size and exposure level. These equations were accurate for different types of beaches, with correlation coefficients around 0.87. This means that we can quickly estimate a beach's slope by knowing the size of its sand grains.