Often, landowners along eroding beaches will build groins, which are walls or dams sticking out into the ocean or lake from the beach. why are these built, and what happens? group of answer choices the landowners are trying to block the energy of the waves, which usually turn to move almost parallel to the beach; this can work, but often increases energy on the "upstream" side of the groin and makes the neighbors mad. the landowners are trying to catch sediment from the longshore drift to add to the beach; this almost always works well. the landowners are trying to make a nice photographic platform from which to take pictures of their houses falling apart during the next storm. the landowners are trying to block the energy of the waves, which usually turn to move almost parallel to the beach; this almost always works well. the landowners are trying to catch sediment from the longshore drift to add to the beach; this can work, but often erosion on the "downstream" side of the groin makes the neighbors mad.