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Sand movement from Semaphore to West Beach

Fast facts about the sand movement underway from Semaphore to Adelaide’s southern beaches.

Sand from the beach between Semaphore and Largs Bay jetties will be skimmed using a land plane (pictured) attached to a tractor, from between the high and low tide mark. Sand will be then moved along the beach, under the Semaphore jetty to Point Malcolm, then transported to West Beach.

West Beach and Henley Beach South are eroding. A measure to replenish these beaches is to move sand from Semaphore to these eroding southern beaches

Fast facts:

  • Why can’t Adelaide’s coastline just be left alone? Adelaide’s roads, houses and other infrastructure were built along the foreshore before it was commonly understood that Adelaide’s sand naturally moved south to north. Maintaining a stable coastline by moving and recycling sand allows us to enjoy sandy beaches, as well as saving South Australians from the costs of damaged assets and infrastructure.
  • Why does sand need to be moved? From all the studies and evidence, the most practical and cost-effective ways to deal with erosion on Adelaide’s southern beaches are to recycle sand from Adelaide’s northern beaches, and bring in additional sand from external sources.
  • What about the health of Adelaide’s northern beaches? Semaphore beach has plenty of sand. As sand moves north on Adelaide’s coast, the Semaphore area will naturally accrue sand, as it did when similar sand movement occurred in the early 2000s, 1990s and 1980s.
  • How’s the health of Adelaide’s southern beaches? West Beach and Henley Beach South are eroding quickly. Today, beach levels at West Beach and Henley Beach South are lower than at any other time since records began. The beaches between Kingston Park and Glenelg have been maintained by sand pumping system along that part of the coast since 2013.
  • Why has the sand movement works from between the Semaphore and Largs Bay jetties changed? Recently the works to move sand from between the Semaphore and Largs Bay jetties were modified to alleviate community concerns. Sand will be moved from between the Semaphore and Largs Bay jetties for five days, from 11 November until 15 November 2019. The small window of sand movement works is due to weather and tides to enable access under the Semaphore jetty, to move sand along the beach to the Semaphore South breakwater.
  • How is sand collected between the jetties? Sand from the beach will be skimmed using a land plane attached to a tractor, from between the high and low tide mark. Sand will be then moved along the beach, under the Semaphore jetty to Point Malcolm, then transported to West Beach.
  • Why not build groynes to hold sand on beaches? Structures like groynes, breakwaters and seawalls can be used to help trap sand and protect infrastructure. But, to manage Adelaide’s coastline well, groynes are not the answer. They are costly to install, require large quantities of sand, interrupt recreational beach use, are visually unappealing and can cause the coast on the southern side of the structure to become starved of sand. By focusing on moving sand, long sandy beaches can be achieved without the additional cost and side-effects of expensive structures.
  • Why is this not ‘sand mining’? Sand in being recycled not ‘mined’. It is the sustainable management of a finite and incredibly valuable resource, and we have been doing it for nearly 50 years. 
  • How can a member of the community find out more? Local residents will be kept informed. To find out more visit the Adelaide beach works website

The State Government is delivering the Securing the Future of our Coastline program, a long-term solution to restore and maintain the sand at West Beach and Henley Beach South. As part of the program, a sand recycling pipeline will be built from Semaphore to West Beach, and about 500,000 cubic metres of external sand will be imported to make up for sand losses over the years. 

 

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