![]() This past February, some local residents urged that a channel be cut through the sand spit to allow the river to return to a north-south orientation. In its inexorable eastward march, the river had even cut through the sand bar, known as a tombolo, making it nearly impossible for visitors to walk from Popham to Fox Island. State geologists say it’s the beach’s greatest retreat in a century. The ocean was within feet of the parking lot, and it threatened the park’s new bathhouses. Erosion had carved deeply into the dunes and toppled hundreds of shoreline pine trees. ![]() Even so, the stunning changes at Popham had observers “in a panic” by this past winter, Retelle says. River outlets are always “the most dynamic places” along the coast, says Retelle. “You want to see natural processes play out,” Retelle says. As the Morse curved into Popham Beach, the strongest part of the current was eating away at the beach. As kayakers and canoeists know, when a river curves, the fastest and most powerful flow is the outside of the curve. The sand spit deflected the river toward the beach, and the erosion just got worse and worse. This aerial photograph of Popham Beach on March 10, 2010, shows key elements of erosion: (1) the new channel cut by the Morse River last winter, which should save the beach (2) the old channel that for years had eroded the west side of Popham (3) the tombolo that makes it possible to walk to rocky Fox Island at low tide. Retelle and Dana Oster ’09 dubbed the Morse River spit “I-95” for its great length and width, and it became an “insurmountable barrier” that blocked the Morse from flowing directly into the ocean. The spit was created by a wave and sand mechanism called longshore sand transport, in which sand-carrying waves hit the shore at an angle and gradually deposit their sediments. One was the relentless growth of a sand spit just offshore from the Morse River outlet. Two factors pushed the river toward the beach. By 2005, he says, “we started noticing massive changes” to the Morse River and Popham Beach. ![]() “We’ve been watching this river shift its course gradually for a long time,” says Bates geology professor Mike Retelle. In recent years, the river has migrated eastward, cutting away at Popham’s beach, particularly the western part of the beach, though the center beach, which connects to Fox Island, has also been eroded significantly. If Popham Beach is this story’s protagonist, then the antagonist is the Morse River, which exits the coast just west of Popham Beach. The roiling sea in December 2009 threatens the picnic area at Popham Beach.
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