Multiscenario flood hazard assessment using probabilistic runoff hydrograph estimation and 2D hydrodynamic modelling

Abstract

In this paper, we aim to define a procedure of flood hazard assessment applicable to large river basins in which flood events can be induced/sustained by the full basin area or by fractions of the total area as functions of the extent of the triggering precipitation event. The proposed procedure is based on a combined approach accounting for (1) the reconstruction of intensity–duration–frequency curves expressing the magnitude in terms of intensity for multiple return periods; (2) the application of the soil conservation service method for runoff estimation from a selected rainfall scenario considering some characteristics of the basin (i.e. soil type, land use/treatment, surface condition, and antecedent moisture conditions); (3) 2D hydrodynamic modelling conducted by the HEC-RAS model using runoff hydrographs as hydrological input data; (4) the reconstruction of flood hazard maps by overlaying multiple inundation maps depicting flood extent for different return periods. To account for the variability in the extent of the triggering precipitation event and the resulting input hydrograph, multiple contributing areas are considered. The procedure is tested at the archaeological site of Sybaris in southern Italy, which is periodically involved in flood events of variable magnitude. The obtained results highlight that the variable extent of the floodable area is strongly conditioned by the extent of the contributing area and return period, as expected. The archaeological site is always involved in the simulated flooding process, except for the smallest contributing area for which only a 300-year event involves this part of the site. Our findings may be useful for developing and supporting flood risk management plans in the area. The developed procedure might be easily exported and tested in other fluvial contexts in which evaluations of multiple flood hazard scenarios, due to the basin geometry and extent, are needed.

Comparison of Two Hydrological Models, the HEC-HMS and Nash Models, for Runoff Estimation in Michałówka River

“…The SCS-CN model is a frequently used model. In recent years, this model has been used on the application of methods for hydrogram estimation and flood modelling [54]. However, other hydrological models are also used for controlled catchments [55].…”

Evaluation of Flood Mitigation Physical Examination in Zhengzhou City from the Perspective of Resistance

“…Another contribution is that the paper did not only use the weighted average of two objective methods to find the resistance index of each area of the city, which is different compared to the previous methods of subjective [50,51] and fuzzy evaluation [52,53] that were mostly used in the construction of the index system, which can effectively avoid the subjectivity in the evaluation process. Moreover, the barrier degree model was introduced to analyze the main barrier factors to the development of each area, which can identify and clarify the factors that have a major impact on the evaluation results and provide certain ideas for the scientific formulation of the future development path of the city compared to the evaluation of flood risks using hydrological models [54,55] and hydrodynamic models [56,57].…”

County-Level Flash Flood Warning Framework Coupled with Disaster-Causing Mechanism

“…Furthermore, some experts have attempted to employ both hydrodynamic models and machine learning. Tufano et al [15] used a two-dimensional hydrodynamic model to generate flood inundation maps and obtained the risk range by overlaying the layers. Janizadeh et al [16] utilized various machine learning methods to assess flash flood susceptibility in the Tafresh watershed in Iran.…”