Abstract:
Accurate estimation of Manning’s roughness coefficient is critical for reliable hydraulic
modeling of dam-break floods. However, for this type of accident, the lack of historical
flood data makes the definition of Manning’s roughness coefficient challenging. This
study utilizes high-resolution land use and land cover (LULC) data to determine Manning’s
roughness coefficient values for application in dam-breaking studies. This study
assesses the influence of a regional high-resolution LULC dataset (MapBiomas) and two
high-resolution LULC datasets (Dynamic World and ESRI 10 m Annual) on hydraulic parameters
related to flood wave propagation and flood hazard assessment. The simulations
indicated substantial variations in flood behavior across the Dynamic World generated
predominant regions with elevated Manning values, resulting in expanded flood zones
and heightened flow attenuation simulations. Conversely, the ESRI 10 m Annual exhibited
predominant regions of lower roughness, leading to simulations with diminished flood
areas, reduced propagation times, and decreased attenuation of peak flows. Compared
with the other LULC datasets, MapBiomas demonstrated a balanced representation of
the Manning coefficient’s domains and yielded intermediate outcomes. These discrepancies
highlight the challenges associated with accurately determining Manning’s values to
ensure precise outcomes in flood modeling. The quality of this modeling is critical for
identifying risks, formulating emergency responses, and implementing effective mitigation
strategies in downstream regions.
