Soft Engineering Method
Beach Nourishment
As shown in figure 1, beach nourishment Is the process of dumping or pumping sand from elsewhere onto an eroding shoreline (due to sediment lost through longshore drift or erosion) to create a new beach or to widen the existing beach. Beach nourishment does not stop erosion, it simply gives the erosional forces something else to 'chew on' for awhile.
Advantages:
Disadvantages:
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Figure 1: Beach nourishment in Australia using the rainbow method.
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Location in Australia: The Gold Coast
"Beach nourishment projects have been undertaken on the Gold Coast since 1974. They are designed to mimic natural coastal processes and allow sand to shift continuously in response to changing waves and water levels. They are a prime example of how Gold Coast City Council’s coastal engineering activities are working with nature to care for our coast, and achieve better outcomes for the community, economy and environment of the Gold Coast. There are several positions along a beach that may be nourished as part of a beach nourishment project: beach berm, submerged berm, or as a dune. Wind, tides, currents and waves act naturally on the beach to redistribute this sand across the beach system. This nourishment enhances the natural buffering ability of the beach sand store (including its dunes, visible beach, and submerged beach) and protects our valuable coastline.
Beach nourishment projects on the Gold Coast are planned very carefully. Variations in physical, geological, environmental and economic characteristics of the beach must be taken into account, as well as the level of protection required. Extensive modelling is undertaken in the planning phase of a beach nourishment project, taking into consideration expected beach behaviour under a variety of storm scenarios. Currently, sand dredged from Currumbin Creek is used to nourish Southern Palm Beach, Tallebudgera Creek is dredged to nourish Burleigh Beach, and nourishment of southern Gold Coast beaches is ongoing through the Tweed River Estuary Sand Bypassing Project." - City of Gold Coast website.
Back when we were not aware of the consequences of building too close to the beach and the effects of longshore drift, Australian's built on the beach for short term economic gains. There was even a case where a building fell into the ocean due to the effects of a severe cyclone. As the years went by, the beach got smaller and smaller, and the waves got closer and closer. As the sand supply was depleted, combined with a series of severe cyclones (Dinah, Barbara, Dulcie, Elaine and Glenda) in 1967, 8 million cubic metres of sand was eroded from the beaches and threatened the backing Gold Coast roads, houses and hotels. The solution has been threefold. 2 of the techniques used was beach nourishment. Between 1995 and 2000 3.5 million cubic meters of sand was dredged from the Tweed Bar and placed offshore of the southern Gold Coast beaches. A permanent pumping system was built just south of the training wall, which since 2000 has pumped more than 500 000 m3 of sand each year from New South Wales across the border onto the Gold Coast beaches. In 2007 these beaches were as wide was they have ever been. However it has all come at a cost in the tens of millions of dollars.
Beach nourishment projects on the Gold Coast are planned very carefully. Variations in physical, geological, environmental and economic characteristics of the beach must be taken into account, as well as the level of protection required. Extensive modelling is undertaken in the planning phase of a beach nourishment project, taking into consideration expected beach behaviour under a variety of storm scenarios. Currently, sand dredged from Currumbin Creek is used to nourish Southern Palm Beach, Tallebudgera Creek is dredged to nourish Burleigh Beach, and nourishment of southern Gold Coast beaches is ongoing through the Tweed River Estuary Sand Bypassing Project." - City of Gold Coast website.
Back when we were not aware of the consequences of building too close to the beach and the effects of longshore drift, Australian's built on the beach for short term economic gains. There was even a case where a building fell into the ocean due to the effects of a severe cyclone. As the years went by, the beach got smaller and smaller, and the waves got closer and closer. As the sand supply was depleted, combined with a series of severe cyclones (Dinah, Barbara, Dulcie, Elaine and Glenda) in 1967, 8 million cubic metres of sand was eroded from the beaches and threatened the backing Gold Coast roads, houses and hotels. The solution has been threefold. 2 of the techniques used was beach nourishment. Between 1995 and 2000 3.5 million cubic meters of sand was dredged from the Tweed Bar and placed offshore of the southern Gold Coast beaches. A permanent pumping system was built just south of the training wall, which since 2000 has pumped more than 500 000 m3 of sand each year from New South Wales across the border onto the Gold Coast beaches. In 2007 these beaches were as wide was they have ever been. However it has all come at a cost in the tens of millions of dollars.
Figure 2: The Gold Coast in recent years