Reconstruction of a flash flood event using a 2D hydrodynamic model under spatial and temporal variability of storm

Bellos, Vasilis; Papageorgaki, Ino; Kourtis, Ioannis M.; Vangelis, Harris; Kalogiros, John; Tsakiris, George

doi:10.1007/s11069-020-03891-3

Cited by 58 publications

(26 citation statements)

References 38 publications

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“…The model set up was also based on a forecasting mode adopting even 5-min forcing approach, features that additionally attach importance to the entire effort. The use of smaller forcing timestep partially explains the differences (from −30 to +70%) evidenced between the simulated discharge maxima of this study and the respective simulated maxima of previous studies (Bellos et al, 2020;Diakakis et al, 2019;Spyrou et al, 2020;Varlas, Anagnostou, et al, 2019). Moreover, regarding the previous studies of Mandra's flash flood event, it is important to mention that our study is the only one that a hydraulichydrodynamic model has been used for flood inundation modelling and mapping, and the results were evaluated against a flood extent validation polygon.…”

Section: Discussionmentioning

confidence: 67%

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Investigating sea‐state effects on flash flood hydrograph and inundation forecasting

Papaioannou

Varlas

Λουκάς

et al. 2021

Hydrological Processes

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A common source of uncertainty in flood inundation forecasting is the hydrograph used.Given the role of sea-air-hydro-land chain processes on the water cycle, flood hydrographs in coastal areas can be indirectly affected by sea state. This study investigates sea-state effects on precipitation, discharge, and flood inundation forecasting implementing atmospheric, ocean wave, hydrological, and hydraulic-hydrodynamic coupled models. The Chemical Hydrological Atmospheric Ocean wave System (CHAOS) was used for coupled hydro-meteorological-wave simulations 'accounting' or 'not accounting' the impact of sea state on precipitation and, subsequently, on flood hydrograph. CHAOS includes the WRF-Hydro hydrological model and the WRF-ARW meteorological model two-way coupled with the WAM wave model through the OASIS3-MCT coupler. Subsequently, the 2D HEC-RAS hydraulic-hydrodynamic model was forced by the flood hydrographs and map the inundated areas. A flash flood event occurred on 15 November 2017 in Mandra, Attica, Greece, causing 24 fatalities, and damages was selected as case study. The calibration of models was performed exploiting historical flood records and previous studies. Human interventions such as hydraulic works and the urban areas were included in the hydraulic modelling geometry domain.The representation of the resistance caused by buildings was based on Unmanned Aerial System (UAS) data while the local elevation rise method was used in the urban-flood simulation. The flood extent results were assessed using the Critical Success Index (CSI), and CSI penalize. Integrating sea-state affected the forecast of precipitation and discharge peaks, causing up to +24% and from −8% to +36% differences, respectively, improving inundation forecast by 4.5% and flooding additional approximately 70 building blocks. The precipitation forcing time step was also highlighted as significant factor in such a small-scale flash flood. The integrated multidisciplinary methodological approach could be adopted in operational forecasting for civil protection applications facilitating the protection of socio-economic activities and human lives during similar future events.

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Section: Discussionmentioning

confidence: 67%

“…These values were set after performing several calibration tests. Since the Mandra's watershed is ungauged, the calibration process was based on the comparison of the current simulated discharge with discharge estimates obtained from previous studies (Bellos et al, 2020; Diakakis et al, 2019; Spyrou et al, 2020).…”

Section: Methodsmentioning

confidence: 99%

Investigating sea‐state effects on flash flood hydrograph and inundation forecasting

Papaioannou

Varlas

Λουκάς

et al. 2021

Hydrological Processes

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“…Greece also suffers from local flash floods causing severe damages, economic losses, and even fatalities [17]. Noteworthy flash flood events in Greece occurred at Mandra town on 15 November 2017 [17][18][19][20][21][22][23], at Volos city on 9 October 2006 [24], and at Rafina catchment on 11 December 2009 and 22 February 2013 [25]. The hydrometeorological forecasting and warning services in small-scale catchments demand a high resolution to capture the specific spatiotemporal characteristics of the flash flood events [26].…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Forecast Skill of a Hydrometeorological Modelling System in Greece

et al. 2021

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A hydrometeorological forecasting system has been operating at the Institute of Marine Biological Resources and Inland Waters (IMBRIW) of the Hellenic Centre for Marine Research (HCMR) since September 2015. The system consists of the Advanced Weather Research and Forecasting (WRF-ARW) model, the WRF-Hydro hydrological model, and the HEC-RAS hydraulic–hydrodynamic model. The system provides daily 120 h weather forecasts focusing on Greece (4 km horizontal resolution) and hydrological forecasts for the Spercheios and Evrotas rivers in Greece (100 m horizontal resolution), also providing flash flood inundation forecasts when needed (5 m horizontal resolution). The main aim of this study is to evaluate precipitation forecasts produced in a 4-year period (September 2015–August 2019) using measurements from meteorological stations across Greece. Water level forecasts for the Evrotas and Spercheios rivers were also evaluated using measurements from hydrological stations operated by the IMBRIW. Moreover, the forecast skill of the chained meteorological–hydrological–hydraulic operation of the system was investigated during a catastrophic flash flood in the Evrotas river. The results indicated that the system provided skillful precipitation and water level forecasts. The best evaluation results were yielded during rainy periods. They also demonstrated that timely flash flood forecasting products could benefit flood warning and emergency responses due to their efficiency and increased lead time.

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“…The equations discretization use the Godunov method (Toro, 2001), which can capture the shock wave accurately and deal with the sharp change of bed form stably. The calculation time is acceptable, and is a very promising tool (Cao, et al, 2011;Yang, et al, 2014;Kvočka, et al, 2015;Yoshioka, et al, 2015;Guan, et al, 2016;Liang, et al, 2016;Hu and Song, 2018;Bellos, et al, 2020;Contreras and Escauriaza, 2020;Khosronejad, et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of a Flash Flood Process that Occurred in Zhongdu River, Sichuan, China

et al. 2021

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In 2018, a flash flood occurred in the Zhongdu river, which lies in Yibin, Sichuan province of China. The flood caused many casualties and significant damage to people living nearby. Due to the difficulty in predicting where and when flash floods will happen, it is nearly impossible to set up monitors in advance to detect the floods in detail. Field investigations are usually carried out to study the flood propagation and disaster-causing mechanism after the flood’s happening. The field studies take the relic left by the flash flood to deduce the peak level, peak discharge, bed erosion, etc. and further revel the mechanism between water and sediment transport during the flash flood This kind of relic-based study will generate bigger errors in regions with great bed deformation. In this study, we come up with numerical simulations to investigate the flash flood that happened in the Zhongdu river. The simulations are based on two-dimensional shallow water models coupled with sediment transport and bed deformation models. Based on the real water level and discharge profile measured by a hydrometric station nearby, the numerical simulation reproduced the flash flood in the valley. The results show the flood coverage, water level variation, and velocity distribution during the flood. The simulation offers great help in studying the damage-causing process. Furthermore, simulations without considering sediment transport are also carried out to study the impact of bed erosion and sedimentation. The study proved that, without considering bed deformation, the flood may be greatly underestimated, and the sediment lying in the valley has great impact on flood power.

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Reconstruction of a flash flood event using a 2D hydrodynamic model under spatial and temporal variability of storm

Cited by 58 publications

References 38 publications

Investigating sea‐state effects on flash flood hydrograph and inundation forecasting

Investigating sea‐state effects on flash flood hydrograph and inundation forecasting

Evaluating the Forecast Skill of a Hydrometeorological Modelling System in Greece

Numerical Investigation of a Flash Flood Process that Occurred in Zhongdu River, Sichuan, China

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