Assessment of Tsunami Damage to Mangrove in India Using Remote Sensing and Gis

Indian Ocean is the home to rare flora and fauna that act as the bio-shield to many coastal communities. Indian Ocean experienced the world’s most deadly natural disaster “Tsunami” on 26 December, 2004, which on one hand is unparallel in the history considering its magnitude and devastation and on the other hand, caused an unprecedented impact on the aqua and aqua terrestrial ecosystems. One of the worst effected flora is the mangrove species that is among the richest in the world. There are places where vast pristine tracts of mangroves have been destroyed and it may pose a long-term threat for the region, not only in terms of forest and biodiversity conservation but also in terms of the ability of the ecosystem to support the livelihoods and the coastal communities. The tragedy of Tsunami invoked the rationale for conserving and sustainably managing natural ecosystems among the researchers and scientific community. The present research was carried out to make a post Tsunami evaluation of India’s most ecologically fragile areas of Gulf of Mannar and South Andaman Island. Indian Remote Sensing Satellite (IRS 1C) and (IRS 1D) LISS (Linear Imaging Self Scanner)-III and Resourcesat –I LISS IV data have been effectively used to detect, assess and monitor the changes in the mangroves in the Pre and Post Tsunami period using multi-temporal optical satellite data. On-screen visual interpretation was done using FCC of the data to identify the heterogeneous patches for the preliminary classification of fieldwork. A supervised classification was performed using Gaussian Maximum Likelihood (GML) classifier to obtain the pre and post Tsunami land cover maps. Accuracy assessment of the classified maps was performed on pixel level using ground truth. The changes in the pre and post classification maps were performed by comparison of area basis based on different land use classes. The result highlighted the changes in the spatial extent of the mangroves and other land cover categories in the study areas as a result of Tsunami. The Damage map showed the degree (intensity) and extent of damage in mangroves on a qualitative basis.