Abstract. 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.
A new record of Leodia sexiesperforata is reported from the coast of Rio Grande do Norte state, northeastern Brazil. An updated distribution map based on data collected from literature, museums, and scientific collections is also presented. This new report fills a distribution gap on the coast of northeastern Brazil. Leodia sexiesperforata has a continuous range between the states of Ceará and Alagoas.
First record of the association between the porcellanid crab Porcellana sayana and the brachyuran crab Stratiolibinia bellicosa carlos eduardo rocha duarte alencar 1 , alex barbosa moraes 1 , sa ' vio arcanjo santos nascimento moraes 1 , paulo victor nascimento arau ' jo 1,2 and fu ' lvio aure ' lio morais freire 1The porcellanid crab Porcellana sayana is, for the first time, reported to have a symbiotic association with the crab Stratiolibinia bellicosa. This is also the first record on the association between the porcelain crab P. sayana and a brachyuran crab on the Brazilian coastline. In addition, this is the second record of association of P. sayana with a Majoidea crab.
Abstract. 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 15River 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 20 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 25 impact of flood events by supporting the process of land use planning in areas exposed to flood geohazard.
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