ANNOUNCEMENTS
The 2018 Kerala floods left the state in a state of turmoil. The present study attempts to map the extent and depth of the event using high resolution Sentinel-1 SAR data. Floodwater depth is mapped using the FwDET (Flood water depth extraction)tool. Further impact assessment is done to examine the magnitude of loss from the event after which the change in runoff of Ernakulum over the span of thirteen years from 2005, 2010, 2015 and 2018. It was seen that the total flood extent was 684.42 sq. Km, the total affected cropland area was 15087 hectares and about 110287 people were exposed to the flood, with the most affected districts being Kottayam, Thrissur and Alapuzha. Floodwater depth using FwDET tool was seen to accurately vary from 0 to 2.5 m in various areas with high level of inundation in areas of Thrissur and Kole wetlands having an increase in water level of 5 m and 10m respectively, which can be attributed to their low relief. The study further showed that the floods greatly impacted the agricultural, power and social sector with large number of claims made for infrastructure from Thrissur and Ernakulum districts. It was observed that although the kharif production of all the major crops decreased, the yearly production was increased compared to the previous three years, due to higher production during the Rabi season. Yearly production of rice in state was 578255.618 tonnes as compared to 521310 tonnes in 2017. The runoff in Ernakulum from 2005 to 2018 increased from 138.107 mm to 196.953 mm, not a large difference is seen between the runoff in 2010 and 2018 which was 161.44 mm and 196.95 mm respectively.
Keywords: Flood, Sentinel-1, Sentinel-2, FwDET, Runoff, SCS-CN method
