Change analysis of water area and flood mapping using a novel water index 2020 (WI2020) for Landsat imagery

The present study deals with Landsat data for the change analysis and flood mapping using water class extraction. Among the various available bands, the most suitable band combination is identified using class separability analysis and a novel water index (WI2020) is proposed for the extraction of water. The proposed index is able to separate the water class from other land features and performs better than NDWI. The index-based results are also validated through supervised classification and used for change analysis and flood mapping. The change analysis is done in two ways, viz., from the year 2000 to 2020 in a span of 5 years in a periodic manner and from the year 2014 to 2020 in a continuous manner. The flood mapping is done on the images of 2014 and 2016 along with the pre-flood and post-flood situations with the help of WI2020 which gives quantitatively satisfactory results.