BHUBANESWAR: Cyclone storm Amphan had severe ecophysical effects on the coasts of Odisha, West Bengal and Bangladesh, eroding coastlines and damaging mangrove vegetation. This was demonstrated by the first technology-based study of the effects of cyclones along the east coast conducted by a group of four independent researchers from Delhi University, Sambalpur University, Khallikote University and Adamas University in Kolkata.
They found that the highest coastal erosion of 186.47 meters occurred in Balasore, 275.53 meters on Patharpratima Island in West Bengal and 486.85 meters along the Patharghata region of Barisal subdistrict in Bangladesh. Although the post-cyclone effects on people and the economy will be assessed by the government, the ecology is often ignored. Analysis of the coastline change in Odisha showed erosion in 43.93 percent (pc) of the transects, while it was highest at 76.94 percent in Bangladesh and 64.94 percent in West Bengal.
The entire coastal region of 48,212.4 square kilometers was affected by the Amphan cyclone, which hit the coast between May 16 and 20 last year. The researchers found a total of 4,545 post-cyclone transects in the study area. The study carried out with geodata technology showed that about 60.33 percent of the total transects of the study area were eroded, but only 24.99 percent of the total transects grew and 14.68 pc of the total transects represented stability.
The coastal districts of Kendrapara, Bhadrak and Balasore, in which 40.93 percent of the total transects are of erosive character, were affected by the cyclone northeastern extension of the Balasore district. The highest accumulation of 137.85 meters was also observed along the southern part of the headland, ”said the researcher Manoranjan Mishra.
The eastern coastal region is the focus of the cyclone landings that have occurred over the past 140 years. The most critical tropical ecosystems – the Sundarbans mangrove area and the Bhitarkanika mangrove and biosphere reserve – fall within the region. Associate professor in the Department of Natural Resources Management and Geo-Informatics at Khallikote University, Mishra, said Amphan has also severely affected vegetation and the green cover is degrading along the coast of Bangladesh. The relatively minor impact of the cyclone on the Odisha coast may have kept the vegetation relatively healthier.
Ortho-rectified Landsat images from April to July 2020, showing the period before and after the cyclone, were used to determine the coastline change. Monitoring of the vegetation was carried out using images obtained from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS).