How mangroves in Odisha reduced cyclone Dana's impact

When nature threatens, it often holds the key to our protection as well. The paradox was evident along Odisha’s coast, where the dense mangrove forests played a crucial role in reducing the impact of Cyclone Dana. The cyclone made landfall close to the Bhitarkanika National Park and Dhamra Port in Odisha at 3:30 a.m. on October 25. However, the cyclone was prevented from wreaking havoc on the area, both due to the vigilance of the authorities—who had evacuated one million people to cyclone shelters—and the mangrove trees of Bhitarkanika.


According to divisional forest officer Sudarshan Jadhav from the Mangrove Division in Rajnagar, there was minimal damage from Cyclone Dana. Only a few windows and doors suffered damage, while the rest of the structures remained unharmed. He also added that even though the wind exceeded speeds of 100-120 km/h in the core area of the park and at the place of landfall, the damage was minimal due to the protection provided by mangrove forests. The mangrove forests significantly buffered the winds, reducing the cyclone's impact, though some branches were broken in the process.

Mangroves are salt-tolerant trees and shrubs and are mainly found in areas where freshwater and saltwater meet. Mangroves play an important role in protecting the ecosystem. For starters, mangrove roots, particularly their dense and above-ground structures, play a crucial role in stabilizing and building soils. These roots slow water flow, promote sediment deposition, and help prevent erosion. Over time, mangroves can actively accumulate soil, gradually increasing its thickness—a vital function as sea levels continue to rise.

But other than binding the soil, the mangrove forests have been protecting Odisha from the wrath of Cyclone Dana. Odisha has the second-largest reserve of mangrove forest area. It is spread over an area of 231 sq km, with a major chunk in Bhitarkanika. When the cyclone hits, mangrove trees obstruct the water through their husks, roots, and leaves. A study reveals that surge height was reduced from 4 cm to 16.5 cm with mangrove strips ranging from 50 m to 2 km in width for certain mangrove species, such as 'Sonneratia apetala'. Water flow velocity was also decreased by 29% to 92% with mangrove forests of 50 m or 100 m in width.