Figure 5. This figure shows a map of Popham Beach and dunes based on conditions in 1986, when the Morse River was farther west than today and Popham dunes were more expansive. The frontal dune (D1) is the seaward-most ridge of sand and the most active portion of the dune system. Most of the 1986 frontal dune is now gone (compare this photo to Figure 4). The back dune (D2) is more stable, has older vegetation including pitch pine trees, and less dense American beachgrass. The sand beach (B1) fringes the dunes. Historical shoreline mapping by the Maine Geological Survey uses the seaward edge of vegetation (the B1-D1 boundary line) to calculate erosion and accretion rates. For a more complete description of map units see Dickson (2001).
Last updated on April 8, 2008