Description:Shorelines are continuously moving in response to winds, waves, tides, sediment supply, changes in relative sea level, and human activities. Shoreline changes are generally not constant through time and frequently switch from negative (erosion) to positive (accretion) and vice versa. Cyclic and non-cyclic processes change the position of the shoreline over a variety of timescales, from the daily and seasonal effects of winds and waves, to changes in sea level over a century to thousands of years. The shoreline "rate of change" statistic thus reflects a cumulative summary of the processes that altered the shoreline for the time period analyzed.