ANNOUNCEMENTS
A flood is one of the most destructive catastrophic events which causes loss to humans in a lot of ways, be it economic loss, casualties, or infrastructural damage. There is no possible way to completely avoid a flood event but there are several ways by which the magnitude of a flood can be minimised.
There are a lot of mitigation techniques and a lot of ways to apply flood defences in order to minimize its impact, but these techniques are only useful when a flood event location can be easily and swiftly be identified and a quick action can be planned. To achieve such a target, modern day remote sensing as well as GIS techniques have been playing quite a crucial role. The mapping and monitoring of a flood event has now become easy, thanks to the n number of techniques available to map, monitor and analyse an on-going or a historic flood event.
This study aims to develop a robust and rapid flood mapping and depth estimation tool so that it can be used in near real time by event response teams. The study rea chosen for testing to this technique is Assam as it is one of the most frequently flood state of India.
Sentinel 1 SAR microwave imagery has been used in this study for the purpose of flood detection. A thresholding-based change detection methodology has been used to detect flood and this technique has been applied on Assam to identify flood events from 2015 to 2020. A flood frequency map has been prepared based on the flood images derived from the flood mapping algorithm used.
A flood depth estimation technique has also been used to estimate the flood depth of the inundation maps derived. The areas with a high flood frequency and a high level of flood depth have been further analysed to investigate the reason behind their vulnerability. For that purpose, the precipitation data as well as the geography the vulnerable areas has been analysed. The study is finally concluded with identified flood prone zones and the reason behind their vulnerability.
