What are some of the important factors influencing beach shape?
Major factors on beach morphology in Maine include sea-level rise, waves, currents, tides, and winds, underlying geology, sediment supply, shoreline stabilization, development pressure, and recreational usage. Sea level at Portland, Maine has risen about 0.6 ft in the last century. Global sea level is forecast to rise about 2 feet in the next 100 years. Beaches transgress, or move landward, in response to sea-level rise. If sea level rises faster than sediment supply can keep up, beaches can disappear. Waves, currents, tides and winds are daily forces that influence the shape of our shorelines on time-scales that humans can plainly see. Underlying geology can influence sediment supply, the pathways along which sediment may move, and where accretion or erosion takes place. Sediment supply is extremely important in determining whether a beach will erode or accrete. Beaches along the Maine coast are supplied with sediment from rivers and the erosion of existing materials in the nearshore
