INDONESIA | Cangga Island

For many years residents and staff at Gangga Island Resort and Spa have been watching the beaches of the island erode. This erosion had come to a point where beachside trees and structures were beginning to collapse into the sea. The damage to the coast was serious and distressing to watch.

Damage like this is happening worldwide due to rising sea levels, but within just a few short years there were areas of Gangga Island with barely any beach at all. The island is affected by the Australian and Indo-Chinese Monsoons, and by late 2015 much of the sand had been washed away, leaving a beach cliff almost 1.5 metres high rather than a stretch of pristine white sand. Something had to be done.

Other methods had been tested, but the decision was made to use a method known as Biorock Anti Wave reefs, which had been seen to work incredibly well in other areas in Indonesia. For example, Pemuteran in the north west of Bali had seen a 99% regrowth of the beaches using Biorock reefs.

Unlike sea walls, which actually make erosion worse due to the rebound of the waves off the wall, Biorock reefs are incredibly simple structures made from wire filled with rock. They are designed to dissipate wave energy before it hits the beach rather than deflect it. Letting the waves pass through disperse the energy of the wave in a more even fashion stopping the full energy of the wave from moving the sand.

The Bioreefs also have a very small electric charge passing through them to prevent rusting and encourage the growth of minerals over the mesh. This in turn creates the perfect environment for the growth of barnacles, oysters and mussels, which prevent the rocks from shifting, solidifying the structure further.

In January 2016, just before the monsoon season set in, 48 Biorock Anti Wave reefs were installed in front of the 200 metres of beach worst affected by erosion. Almost immediately the beach started to regrow.

The amazing news is that since 2016 Gangga’s beaches have completely grown back. This is thought to be one of the fastest beach restorations ever done with results that have astounded locals and scientists alike. Even after a severe storm in January 2017, the beaches are back to their former glory…and possibly even better.

And it’s not just the beaches of Gangga Island that are flourishing. The Bioreefs have also created beautiful new environments for new coral and sea grass growth where fish and other marine life are thriving.

This is solid proof that only wave-absorbing structures can grow beaches back. Seawalls are more expensive, more intrusive and actually accelerate coastal erosion. Dredging, sand dumping and other methods are equally ineffective. Gangga Island’s regrowth shows that Biorock technology is the way forward for protecting our beaches, low islands and coasts. Billions of people’s homes and marine habitats can be saved with this simple, cost-effective method.

This article came from https://www.ganggaisland.com/news/biorock-anti-wave-reefs-really-work-gangga-islands-beaches-completely-grown-back/