A SENTINEL-1 BASED FAST AND UNSUPERVISED FLOOD MAPPING AND MONITORING SERVICE FOR UPPER EAST GHANA

Floods are among the most common disasters and natural hazards in the world, affecting human lives and causing severe economic damage. They are mainly due to extreme weather phenomena but can be aggravated by anthropogenic factors. A fast unsupervised flood mapping method is proposed for the Upper East region in Ghana, an area yearly exposed to flood events due to the spillage of Bagre dam after heavy rains. The method consists in applying an unsupervised threshold imaging technique to Sentinel-1 images, filtering, mosaicking and finally detecting changes in the water maps. The flood maps are made available through the AfriCultuReS' platform at high resolution every 6 days for a large area during the flood-prone period. The thorough validation of the flood products qualitatively by local experts and quantitatively using a global surface water reference dataset for floods, will ensure its adoption by end users for the benefit of local communities.