Author(s): Yiwei Guo; Michael Nones
Linked Author(s): Michael Nones
Keywords: Vegetation coverage; GEE; Field measurement; Po River; Vistula River
Abstract: Since flood hazards cause damages globally and affect millions of people, developing effective flood management plans through hydrodynamic models or other methods is imperative. The accuracy of the model simulation results is governed by the input parameters, especially roughness which is easily influenced by aquatic and riparian vegetation. Because of the ability of vegetation resistance to modify flow velocity, the results are unreliable if the models only simulate clear water without considering sediments and vegetation. With the fast developments of earth observation satellites, monitoring vegetation via remote sensing images far outpaces extracting those information manually during field campaigns. However, quantifying roughness in complex and dynamic vegetation is still a challenge. Aiming to find out how roughness varies with vegetation and quantify this variation, this study combined remote sensing and field measurements of riparian vegetation focusing on two reaches of the Italian Po River (between Boretto and Borgoforte and the Vistula River (Poland) between Deblin and Gusin. The vegetation conditions (diameter and height) obtained by the field measurement are compared to the normalized difference vegetation index (NDVI) extracted from satellite images to build a relationship to be then used in a hydrodynamics model. Simply equations are found to express vegetation height through NDVI value, and can therefore be used for describing the vegetation conditions for the areas with dynamic vegetation. The spatial and temporal distribution of roughness which is more relevant to reality can be a reliable model import to get more accurate simulation results.
Year: 2024