Accretion

Deposition of sediment, usually sand, which is evident by the seaward advance of a shoreline indicator, such as the high water line, berm crest, or vegetation line. Accretion causes the beach to become wider. Opposite of Erosion.

Accretion is the process of coastal dune formation. The process begins with sand deposition on shore, by the movement of the waves. This sand is then dried out by the wind and sunlight, allowing it to be blown to other areas of the beach by the prevailing winds. Sand is the major component in the accretion cycle sand is sourced from weathered or eroded material such as rocks sand is moved through three processes: Saltation, Sedimentation and Surface Creep

Weathering is the breaking down of rock material e.g. sandstone

Erosion is the transplanting of weathered material

There are two types of erosion: Water (fluvial) Water erodes dune ecosystems by moving large amounts of sand away from the beach and dunes Examples of water erosion include: river discharge, long shore drift, wave action and powerful storm waves

Wind (aeolian) Wind moves the particles of fine dry sand away from the shoreline. Wind can move entire dune ecosystems inland.

Most sand is produced by mechanical weathering processes: Hydraulic action: waves act as a driving force against cliff faces to help loosen sand particles Abrasion: loose sand particles rub against other particles like sandpaper to help loosen them which are then pushed onto the beach to begin the accretion cycle

Wave action plays a significant role in the formation of the beach. They assist in both the deposition and erosion of the beach. In calmer weather, the wash of the waves deposit the sand onto the shore while the backwash removes small amounts of material. The amount deposited is much greater during this time. Whilst during more unsettled conditions, such as storms, removal of material is much higher. ([(http://www.landcare.net.au/files/fieldguidebook/coastalerosion.html])