The Fladar Project
Floods are natural hazards with potential for many fatalities and significant economic losses. However the degree of vulnerability to any disaster is also a function of human acts and behavior.
The main objective of the FLADAR project is to follow the steps suggested by the 2007/60/EC Directive on the assessment and management of flood risks in order to conduct initially a preliminary flood risk assessment and then draw flood risk zones for a partially developed watershed in East Attiki. Raingauge-calibrated radar rainfall, distributed hydrologic modeling, advanced methods of integrated modeling at a river basin scale and GIS analysis support the assessment and results of the study.
Learn more about the Fladar project
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Rainfall events
Four significant rainfall events provided from the x-band portable polarimetric radar operated by the National Observatory of Athens (NOA), Greece, support the set up and calibration of the distributed hydrologic model of the studied watershed. Raingauge rainfall data from the METEONET network and the X-basin, both operated by the National Technical University of Athens, were used to calibrate the radar rainfall volume and provide rainfall data in watershed areas where the radar beam was blocked by nearby buildings (NOA greater area) or the quality of measurements was reduced by ground clutter.
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Runoff modeling
The digital elevation model (DEM) of the area, the river shapefile and the CORINE land cover maps were analyzed in GIS in order to set up an initial hydrologic model using the VfloTM software developed by Vieux and Associates, Inc. Vflo is a physics-based distributed modeling system built to take advantage of high resolution rainfall and geospatial data in order to improve the understanding of flooding and support the design of measures that would alleviate stormwater impacts in gauges and ungauged watersheds. Comparative analysis of raingauge rainfall model runs and radar model runs show the importance of detailed rainfall data sets in a hydrologic study.
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Flood analysis
The final part of the project involves the following three steps: 1. Set up and calibrate a hydraulic model for the study area using flow data from the hydrologic analysis and geometric data of the main channel obtained from the GIS analysis of the DEM model and the river shapefile; 2. Run the hydrologic and hydraulic models for design storms of different return period (10 year, 50 year, 100 year, 200 year and 500 year); 3. Draw flood hazard and flood risk GIS maps related to each event and identify locations where Competent Authorities should focus their efforts to avoid future catastrophic losses.
