# A Tool for Pre-Operational Daily Mapping of Floods and Permanent Water Using Sentinel-1 Data
## 6 Conclusions  
The AUTOWADE tool designed for a fully automated service of floodwater/permanent water mapping using Sentinel-1 data has been presented. Although several studies available in the literature dealt with the problem of flood mapping using SAR data, the creation of a processing chain that automates the various steps needed to set up an operational service was rarely tackled. These steps include not only the processing of the SAR images, but also the data procurement and the delivery of the maps to the end-user. The service implemented by AUTOWADE daily generates a map of floodwater/permanent water on a national scale (Italy) with a spatial resolution of 20 \(\times\) 20 m\({}^{2}\) in order to provide the Italian Department of Civil Protection with a systematic detection and monitoring of any event occurring in Italy without requiring any activation. For a given location, the average revisit frequency of the maps is 2-3 days (considering both ascending and descending orbits and orbit overlap). AUTOWADE has been tested in fully pre-operational mode since early 2020. Its daily products are automatically delivered to the Italian Department of Civil Protection and can be visualized through a web portal. AUTOWADE includes an algorithm to map open water, based on the new buffer-form-edge (BFE) approach. The BFE approach combines different techniques such as clustering, edge filtering, thresholding, and region growing. Nonetheless, it is quite simple in computation and effective in identifying bare/scarcely vegetated surfaces covered by water. It is therefore suitable for real-time applications, especially if a large amount of SAR data has to be processed, as necessary for a service working on a national scale. The comparison with maps produced by the Copernicus Emergency Management Service has shown that the BFE approach performs quite well. Moreover, vegetated areas adjacent to those classified as flooded are analyzed in order to fill a portion of the gaps present in the maps likely due to undetected flooded vegetation. Future work will concern the inclusion in the AUTOWADE-derived product of an evaluation of the classification uncertainty. An uncertainty map complementing the water map will be made available to the end user. Moreover, future releases of AUTOWADE will take advantage of more accurate ancillary data, such as the Copernicus DEM and a refined land cover map obtained by complementing the Corine Land Cover product with data provided by the Global Human Settlement Layer to better identify urban areas. Conceptualization, L.P., G.S., and S.P. ; methodology, L.P., G.S., and E.F.; software, L.P. and G.S. ; validation, L.P.; formal analysis, L.P.; investigation, L.P.; resources, L.F.; data curation, G.S., E.F., and L.P.; writing--original draft preparation, L.P., G.S., and E.F.; writing--review and editing, L.P., G.S., E.F., L.F., and S.P. ; visualization, G.S., E.F., and L.P.; supervision, S.P. ; project administration, L.F.; funding acquisition, L.F. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by the Italian Department of Civil Protection, Presidency of the Council of Ministers, through the convention between Department of Civil Protection and CIMA Research Foundation, for the development of knowledge, methodologies, technologies, and training, useful for the implementation of national systems of monitoring, prevention, and surveillance. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Sentinel-1 data are available at [[https://scihub.copernicus.eu/dhus/#/home](https://scihub.copernicus.eu/dhus/#/home)]([https://scihub.copernicus.eu/dhus/#/home](https://scihub.copernicus.eu/dhus/#/home)) (accessed on 31 March 2021). **Acknowledgments:** L.P. acknowledges support from the E-SHAPE project, funded by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 820852.