Coastal Dune Formation of Parangkusumo Beach Yogyakarta

      

     Sand dunes in Parangkusumo a coastal forest formations in addition to formation and formation pes - capre and baringtonia . Dune formation is the formation of hills of sand . Coastal dune formed in Parangkusmo formed by the eruption of Mount Merapi on the sand carried by the flow of the Progo river and Opak river so sedeminted on the beach . With the wind would hinder the movement of sand into the sea so that the sand settles on the beach and into a sand dune . The main factors forming the dune formation is wind and sand supply . The wind from the sea will help hold the sand while the sand supply will regulate the amount of sand in and out towards the sea . The presence of factors - other factors such as topography and slope also affects the shape of the dune . Generally dune formed on the flat topography s.d. rather steep with a certain slope . Parangkusumo has karst hills that serve as windbreaks from the sea so that less get the place out of sand and dune formation that occurs remains stable .

       Factors will affect the extent of dune vegetation in a coastal area . Vegetation can both control the dune area , the area near the coastal dune vegetation will be narrow . Can break down the dune vegetation will be destroyed so that the dune . So with the formation of the dune vegetation will reduce the level of abarasi coast caused by wind and waves . Conditions of coastal vegetation in Parangkusumo generally dominated by plants of the formation such  Ipomea pes -capre , Spinifex , Calatropis gigantea , and types - other types of beach grass . Woody plants are evergreen contained shrimp ( dominant ) and other woody plants such as Acacia mangium , Papyrus , and Gamal . Woody plants are scattered and not in formation as intentionally planted by the community . Form of utilization of the surrounding community is utilizing the dune land for agricultural crops .

     Dune shape is influenced by the wind direction , slope , and topography . From the observation in Parangkusumo there are two forms of the dune is crescent shape Spherical and Parabolic shape . Crescent shape is formed because of the wind that blows from sea to land then reflected by the hills around Parangkusumo so will experience repulsion . Wind direction will be reversed so that the sand dunes as the wind boost to make a sand dune hollow like a crescent moon . General direction of the dune basin leads to the beach . While the parabolic shape is formed due to the sea breeze impulse toward dune so the shape becomes concave . The parabolic shape is commonly seen in the dune immediately adjacent to the coast because the sea breeze is directly about it . The existence of factors will influence the breadth parabolic vegetation . The more dense vegetation that formed the parabolic dune will narrow .