Case Study

Tsunami-Proof Mangrove Seawalls

Nature based climate adaptation

Partners Involved: Mangrove Forests, Local Communities
Type of Partnership: Win-Win for Public and Planet
Partnership Models: Purifier, Isolator, Protector, Moneymaker

Through mangroves restoration and actively removing barnacles from seedlings to allow them to flourish and grow, coastal communities in Vietnam are buffered from devastating natural disasters through the protection offered by the mangroves, at a fraction of the cost of building seawalls.

Mangroves can absorb 70-90% of a normal wave’s impact, providing a natural buffer against inland tidal surges and a form of protection against natural disasters like typhoons and tsunamis. Therefore, many mangrove restoration efforts have been implemented across Asia to simultaneously protect coastal communities from devastating impact, and maintain the important habitat that mangroves provide for other species.

When Typhoon Damrey in Vietnam surged at 100 km/per hour, demolishing buildings and the Da Loc commune’s protective dyke wall, it caused over $4.4 million in damages. But one 500 metre area remained intact; the community had been planting a living wall of mangrove trees to protect against future storms. However, at first, the mangrove trees would die after just 2 months, until one villager diagnosed the problem. Barnacles were attaching themselves to the mangrove seedlings in such numbers that the trees were killed before they could take root. So every month, the villagers wade through the mudflats, scraping off the barnacles with a sharp knife.

This costs just US$1000/ha of planted forest. Based on the losses mangroves prevented previously, each dollar spent returned US$186 in averted damages. Mangrove forest restoration costs range from USD$225/ha (10,000 meters) and as much as USD$500,000/ha. Whereas, the average cost of building artificial breakwaters is US$19,791 per metre ($197.9 million/ha). A 15-mile outer sea wall giant sea wall that will close off Jakarta Bay, will cost around $40 billion.

Elsewhere in Asia, companies like Danone and Credit Agricole have invested around $4 million in mangrove reforestation in exchange for tradable carbon offset credits.

A central collection point extracts and buffers the debris before it is shipped to land. By recycling the debris and selling the semi-finished product directly to B2C companies, The Ocean Clean Up is aiming to make their operation fully self-financed and sustainable.

SDGs Targeted: SDG 11 on Sustainable Cities & Communities, SDG 13 on Climate Action, SDG 14 on Life below Water, SDG 15 on Life on Land

Links & Sources:

Case Study

Tsunami-Proof Mangrove Seawalls

Nature based climate adaptation

Partners Involved: Mangrove Forests, Local Communities
Type of Partnership: Win-Win for Public and Planet
Partnership Models: Purifier, Isolator, Protector, Moneymaker

Through mangroves restoration and actively removing barnacles from seedlings to allow them to flourish and grow, coastal communities in Vietnam are buffered from devastating natural disasters through the protection offered by the mangroves, at a fraction of the cost of building seawalls.

Mangroves can absorb 70-90% of a normal wave’s impact, providing a natural buffer against inland tidal surges and a form of protection against natural disasters like typhoons and tsunamis. Therefore, many mangrove restoration efforts have been implemented across Asia to simultaneously protect coastal communities from devastating impact, and maintain the important habitat that mangroves provide for other species.

When Typhoon Damrey in Vietnam surged at 100 km/per hour, demolishing buildings and the Da Loc commune’s protective dyke wall, it caused over $4.4 million in damages. But one 500 metre area remained intact; the community had been planting a living wall of mangrove trees to protect against future storms. However, at first, the mangrove trees would die after just 2 months, until one villager diagnosed the problem. Barnacles were attaching themselves to the mangrove seedlings in such numbers that the trees were killed before they could take root. So every month, the villagers wade through the mudflats, scraping off the barnacles with a sharp knife.

This costs just US$1000/ha of planted forest. Based on the losses mangroves prevented previously, each dollar spent returned US$186 in averted damages. Mangrove forest restoration costs range from USD$225/ha (10,000 meters) and as much as USD$500,000/ha. Whereas, the average cost of building artificial breakwaters is US$19,791 per metre ($197.9 million/ha). A 15-mile outer sea wall giant sea wall that will close off Jakarta Bay, will cost around $40 billion.

Elsewhere in Asia, companies like Danone and Credit Agricole have invested around $4 million in mangrove reforestation in exchange for tradable carbon offset credits.

A central collection point extracts and buffers the debris before it is shipped to land. By recycling the debris and selling the semi-finished product directly to B2C companies, The Ocean Clean Up is aiming to make their operation fully self-financed and sustainable.

SDGs Targeted: SDG 11 on Sustainable Cities & Communities, SDG 13 on Climate Action, SDG 14 on Life below Water, SDG 15 on Life on Land

Links & Sources: