Natural processes that operate (and may interact) in the geographic environment.

Geographic environment = Tasman Bay coastline between Separation Point and Cable bay.

Natural Process – Wind Action (Aeolian processes) and the formation of Dunes.

A sand dune is an accumulation of sand grains which are deposited by the wind. Dunes are critical environments because of the protection they provide inland areas from storm wave action. A number of conditions are necessary for the formation of dunes. Firstly there needs to be a wide enough area for sand to accumulate hence cliffed coasts with narrow beach systems do not form dunes. A strong prevailing onshore wind is also needed to carry sand from the beach face to the backshore area. Another requirement is for stabilising plants such as marram grass to be present for sand to accumulate around. Finally dune formation requires a beach with a low gradient and large tidal range. This means that the sand has the opportunity to dry out which allows the lighter dryer grains of sand to be transported by aeolian processes. (Fig. 1).

At Tahunanui Beach planting of marram and pingao grasses have occurred to aid dune development.(Fig.2)