Spotlight on sustainable solutions for coastal protection

Along the Asian coastlines there are many areas where rural communities experience alarming rates of sea level rises due to land subsidence up to 10 cm per year. This causes tremendous challenges on how to live there and protect these coasts.

A Dutch-Indonesian team of scientists jointly investigated the potential and limitation of mangrove restoration as a cost-effective and sustainable solution for coastal protection in rapidly subsiding areas.

Unfortunately, precisely in these rural densely populated Asian regions, mangroves have in the past been cleared to free up land for other uses such as aquaculture. This has made these coasts vulnerable to rapid erosion.

Restoring mangroves seems a logical solution to reverse this process and protect these densely populated coastlines. However, this requires understanding if mangroves can cope with extreme rates of relative sea level rises, as experienced in these subsiding areas.

Since 2015 NIOZ researcher Celine van Bijsterveldt visited Indonesia regularly during her studies and her Phd.

“I saw how much the people suffered from coastal erosion and frequent inundation,” Van Bijsterveldt said. “To be able to answer if mangroves can help, I started with obtaining reliable measurements of the subsidence rate. This is extremely complicated if you work so remote.”

Overall, present study highlights the urgency of addressing land subsidence as a critical factor influencing coastal vulnerability. 

In areas where the experienced relative sea level rise caused by subsidence is not compensated by sufficient sediment supply, the mangroves’ ability to stabilize the coastline will deteriorate. This will result in the gradual inland migration of the mangrove forest.

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