The direction of wind-driven waves and currents can impact on the movement of sand along the coastline known as littoral drift. When the waves strike the beach at an oblique angle, the sediment is moved along the beach by the breaking waves.
Although sand can be moved in other directions under different wind conditions, littoral drift typically occurs in a northward direction along the coasts of the South Australian gulfs.
For example, it is estimated that between 40,000 and 70,000 cubic metres of sand is moved north each year along Adelaide’s coast between Brighton and Semaphore.
However, this cycle is dependent upon an adequate supply of sand. Along the metropolitan coast, compared to the amount of sand being transported northward, it is estimated that only about 5,000 cubic metres of sand enters the Adelaide beach system from the south at Kingston Park per year, leading to long-term erosion of the beaches from Kingston park northwards. This has been managed by the South Australian Government since the 1970s to maintain the beaches and protect coastal development.