Spatial Analysis of Land Use and Land Cover Changes Using Spectral Indices in the Tsunami Affected Areas in Kerala, India

Abstract

The study focused on the implication of land use change induced by the post-tsunami reconstruction and rehabilitation initiatives. Two adjoining coastal panchayats of Alappad in Kollam district and Arattupuzha in Alappuzha district, suffered maximum damage by the 26th December 2004 tsunami, were chosen as the study area. In the post-tsunami context, these panchayats received the largest reconstruction and rehabilitation initiatives. Hence implications of post-tsunami reconstruction and rehabilitation on land use in the area was analyzed within a duration of 16 years using multi-temporal Landsat Enhanced Thematic Mapper + and Operational Land Imager satellite data. The land use of 2001 to 2016 were taken into consideration for fulfilling the objective of the study. For the land use classification analysis the study utilizes a variety of spectral indices like Normalised Difference Vegetation Index (NDVI), Normalised Difference Water Index (NDWI)and Normalised Difference Built-up Index (NDBI) to automatically separate one land use/land cover from other. Along with that supervised classification was also done for the final land use classification. The accuracy assessment was followed by the classification and it reflects the accuracy with a kappa value of 0.678 which falls under an acceptable range.The result forms the comparison of each land use from 2001-2016 during a period of 16 years summarizes that the major increase in the study area was observed in built up with an increment of 5.3% in 2001 to 14.3% in 2016 along with a decrease in vegetation from 62.4% to 57.3% .Rest of the land uses shows a marginal change. Thus this study revealed various rehabilitation and reconstruction initiatives after the tsunami have significantly impacted the land use of the area. So proper land use change planning can be adopted to protect the environment and thereby mitigating exposure to future hazards and risk.