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Previous studies on tidal flood mapping are mostly through continental- and/or global-scale approaches. Moreover, the few works on local-scale perception are concentrated in Europe, Asia, and North America. Here, we present a case study approaching a tidal flood risk mapping application in the face of climate change scenarios in a region with a strong environmental and social appeal. The study site is an estuarine cut in the Brazilian semi-arid region, covering part of two state conservation units, which has been suffering severe consequences from tidal flooding in recent years. In this case study, we used high-geodetic-precision data (lidar DEM), together with robust tidal return period statistics and data from current sea level rise scenarios. We found that approximately 327.60 km 2 of the estuary is under tidal flood risk and in need of mitigation measures. This case study can serve as a basis for future management actions, as well as a model for applying risk mapping in other coastal areas. [ABSTRACT FROM AUTHOR]

Previous studies on tidal flood mapping are mostly with continental and/or global scale approaches. Besides, the few works on local scale perception are concentrated in Europe, Asia, and North America. Here we present a case study approaching a flood risk mapping methodology against climate change scenarios in a region with a strong environmental and social appeal. The study site is an estuarine cut in the Brazilian semi-arid, covering part of two state conservation units, which has been in recent years suffering severe consequences from flooding by tides. In this case study, high geodetic precision data (LiDAR DEM), together with robust tidal return period statistics and data from current sea level rise scenarios were used. We found that approximately 118.26 km² of the estuary understudy is at high risk, extremely high risk and urgently in need of mitigation measures. This case study can serve as a basis for future management actions as well as a model for applying risk mapping in other coastal areas. [ABSTRACT FROM AUTHOR]

Flooding is a natural disaster which affects thousands of riverside, coastal, and urban communities causing severe damage. River flood mapping is the process of determining inundation extents and depth by comparing historical river water levels with ground surface elevation references. This paper aims to map flood hazard areas under the influence of the Uruguay River, Itaqui (southern Brazil), using a calibration digital elevation model (DEM), historic river level data and geoprocessing techniques. The temporal series of maximum annual level records of the Uruguay River, for the years 1942 to 2017, were linked to the Brazilian Geodetic System using geometric leveling and submitted for descriptive statistical analysis and probability. The DEM was calibrated with ground control points (GCPs) of high vertical accuracy based on post-processed high-precision Global Navigation Satellite System surveys. Using the temporal series statistical analysis results, the spatialization of flood hazard classes on the calibrated DEM was assessed and validated. Finally, the modeling of the simulated flood level was visually compared against the flood area on the satellite image, which were both registered on the same date. The free DEM calibration model indicated high correspondence with GCPs (R2=0.81 ; p<0.001). The calibrated DEM showed a 68.15 % improvement in vertical accuracy (RMSE = 1.00 m). Five classes of flood hazards were determined: extremely high flood hazard, high flood hazard, moderate flood hazard, low flood hazard, and non-floodable. The flood episodes, with a return time of 100 years, were modeled with a 57.24 m altimetric level. Altimetric levels above 51.66 m have a high potential of causing damage, mainly affecting properties and public facilities in the city's northern and western peripheries. Assessment of the areas that can potentially be flooded can help to reduce the negative impact of flood events by supporting the process of land use planning in areas exposed to flood hazard. [ABSTRACT FROM AUTHOR]

Flooding is a natural disaster which affects thousands of riversides, coastal and/or urban communities causing severe damages. River flood mapping is the process of determining inundation extents and depth by comparing historic river water levels with ground surface elevation referenced. This paper aims to map flood geohazard areas under the influence of the Uruguay River, Itaqui city (Southern Brazil), using calibration Digital Elevation Model (DEM), historic river level data and Geoprocessing techniques. The annual maximum for years of 1942 to 2017, of fluviometric temporal series records of Uruguay River were linked to Brazilian Geodetic System using geometric levelling and submitted the statistical analysis. The DEM was calibrated with Ground Control Points (GCP) of high vertical accuracy based on post-processed high-precision GNSS surveys. Using the temporal series statistical analysis results, was assessed the spatialisation of flood hazard classes on the calibrated DEM and validated. Finally, was visually compared the modelling of the simulated flood level versus flood area on satellite image, which both were registered on the same date. The free DEM calibration model indicated high correspondence with GCPs (R² = 0.81; p < 0.001). The calibrated DEM showed a 68.15 % improvement in vertical accuracy (RMSE = 1.00 m). Were determinate 5 classes of flood hazards: extremely high flood hazard; high flood hazard; moderate flood hazard; low flood hazard; and non-floodable. The flood episodes with return time of 100 years were modelled with 57.24 m altimetric level. Altimetric levels above 51.66 m have high potential of damaging, mainly affecting properties and public facilities in the city northern and western peripheries. The assessment of the areas that can potentially be flooded can help to reduce the negative impact of flood events by supporting the process of land use planning in areas exposed to flood geohazard. [ABSTRACT FROM AUTHOR]