Harbours, marinas and boat ramps are valuable tourism and commercial assets. Their presence can also impact on the local coastal processes. These impacts are considered during the planning stages of the project and marinas are designed to minimise the impacts wherever possible.
Management of harbours and marinas is common practice and often includes sand bypassing using various methods such as trucks, pumping infrastructure and dredging.
In Adelaide, the Glenelg and West Beach harbours obstruct the northerly movement of sand along the coastline causing sand to accumulate on the southern side of these harbours.
In the past, to prevent erosion to the north, sand was moved from the southern side to the northern side of the harbours. Sand building up at these harbours is now used to replenish beaches to the south. This is an effective use of recycling sand as well as reducing harbour management costs.
Similar techniques are used in other harbour management strategies throughout South Australia.
Seagrass wrack, which is shed naturally, can also become a problem when strong or severe weather washes it into boat harbours in large volumes. Dredging is frequently required at some marinas and boat launches, such as Glenelg and West Beach, to remove built-up sand and sea grass, and prepare the harbour for winter storms.