Estimation of flooded areas during the El Niño Costero 2017 event using multisensor satellite data. Case Study: Lower Piura watershed (Peru)

Estimation of flooded areas is a crucial parameter for disaster impact assessment, as it can be an indicator of the degree of economic loss and damage to structures. It is also an indicator of spatial persistence and the evolution of flood events. Therefore, it helps to better understand hydrological conditions and surface water availability and also provides valuable information for post-disaster land use planning. This work proposes a methodology to estimate flooded areas with the use of multitemporal flood extension masks on which the procedure is based. To guarantee a sufficiently high frequency of observation of the flooded areas, data from the Peruvian Satellite System (PeruSAT-1, SPOT, KompSAT-3A) and free access (Sentinel-1, Landsat-8) are analyzed. Satellite image processing and analysis is carried out with an integrated system of dedicated process chains for delimiting the extent of flooding from the aforementioned range of sensors. The effectiveness of the proposed method was demonstrated in the 2017 flood, due to the ElNiño phenomenon, in the northern region of Peru.