How and Why Shorelines Change As the waves gently lap the shore of a beautiful stretch of sandy beach, do you ever wonder where that sand came from?
The answer is: erosion. The source of the sand that created and continues to feed the beaches, dunes, and barrier beaches in Massachusetts comes primarily from the erosion of coastal landforms. For example, the material eroded from the Atlantic-facing coastal bluffs of the Cape Cod National Seashore supplies sand to downdrift (i.e., down current) beaches of the Cape. Erosion, transport, and the accretion that results are continuous and interrelated processes. Every day, wind, waves, and currents move sand, pebbles, and other small materials along the shore or out to sea. Shorelines also change seasonally, tending to accrete slowly during the summer months when sediments are deposited by relatively low energy waves and erode dramatically during the winter when sediments are moved offshore by high energy storm waves, such as those generated by northeasters. Shoreline Change and Coastal Property Given its aesthetic and recreational appeal, the Massachusetts coastal zone has been and conti
