How Can Mangroves Save Coastal Cities

Mangroves act as a barrier in the form of bottom friction, their cross-shore width, and their tree density & shape, in helping to reduce the intensity of the onrush of flood waves and soften the forceful blows of the flood on the coastlines.

 

Approximately half of the world’s population comprising 3 billion people live within 150-200 kilometres of a coastline. By the next quarter of a century, that number is going to double. Primary because of climate change in tandem with rapid coastal development, population growth, and habitat loss, the settlements along these coasts are forever under a threat of an ecological disaster, chiefly that of coastal flooding.

 

If there is any first line of defence — that to natural — against such calamities in most tropical and subtropical regions, it is the mangrove forests.

 

What’s A Mangrove?

 

Any botanical growth — trees, shrubs, ferns, and palms — that lie at the boundary of the land and the sea can be called a mangrove. The roots of the mangroves — which become visible during the low tide — derive their nutrition from the tidal saline/freshwater they are immersed in and from the coastal soil and silt.

 

Coastal Flooding

 

It is these mangrove forests that comes across as a barrier in the form of bottom friction, their cross-shore width, and their tree density & shape, in helping to reduce the intensity of the onrush of flood waves and soften the forceful blows of the flood on the coastline.

 

Since the aerial roots of the mangrove forests hold on to the soil sediments and anchor the terrain between the high and the low tides, the resultant erosion in the inter-tidal areas during storms and floods are much subsidized. The canopy covers of the trees, it’s a trunk, and its roots are successful in deflecting the surge of the storms and the waves. Data extracted from studies show that mangroves are capable of reducing 66% of a wave’s energy within the first hundred meters of the forest width. In the long run, they can also regulate the sea level rise through gradual vertical growth.

 

Tropical Cyclones

 

Out of the total benefit derived by coastal cities from mangroves, around 90% is for protecting them from tropical cyclones.

 

Local Level Protections

 

Cities in the coastal regions experience standard-issue flooding at least once annually. Were it not for the mangroves, then lives of several thousands of people would be annually in danger.

 

Varying Capacities

 

The protective capacity of the mangroves varies from region to region chiefly depending on the residing environmental factors, regional flood and mangrove characteristics, coastal topography, and the inland receptors of damage. Western Pacific and Caribbean islands have emerged as the greatest beneficiaries of the mangroves.

 

Conservation

 

While mangroves continue to deplete alarmingly, the frequency and intensity of coastal disasters will only increase. We’ll need mangroves to the rescue.