The Manning’s Roughness Coefficient Calibration Method to Improve Flood Hazard Analysis in the Absence of River Bathymetric Data: Application to the Urban Historical Zamora City Centre in Spain

The accurate estimation of flood risk depends on, among other factors, a correct delineation the floodable area and its associated hydrodynamic parameters. This characterization becomes fundamental in hazard analyses that are carried out urban areas. To achieve this objective, it is necessary to have topography, both inside riverbed (bathymetry) outside it. Outside riverbed, LiDAR data led an important improvement, but not so riverbed. overcome these deficiencies, different models with simplified bathymetry or modified inflow hydrographs were used. Here, we present model based upon calibration Manning’s n value use abnormally low values made possible reproduce extent flooded flow depth within (outside riverbed) acceptable manner. reduction average error from 50–75 cm (models without “natural” values) only about 10 “calibrated” values), was propagated towards direct damage, which fell 25–30% 5%.