Advances in flash flood research based on dendrogeomorpholog

Flash flood is one of the major natural hazards in China. It seriously threatens the lives of people and property in mountainous areas. Various methods have been developed for flash flood study, but most of them focused on the past few decades. As one of the effective methods of historical flash flood events reconstruction, dendrogeomorphology has been used worldwide. It can provide hazard information with long temporal scale and high temporal resolution, sometimes at the seasonal level. By comparing tree ring width and other growth characteristics between disturbed and undisturbed trees, growth disturbance signals can be found in the disturbed trees. Using the growth disturbance in tree rings, flash flood events can be dated, and then the frequency, size, and spatial distribution characteristics of flash floods that have no or little documentary records can be reconstructed. The discharge of flash flood can be reconstructed quantitatively according to the height of scars or by using hydraulic models. With the development of dendrogeomorphology, research tends to probe into the meteorological driving mechanism of flash floods and the pattern of flash floods on a larger spatial scale. In the practical application of dendrogeomorphology, more instrumental data and historical records are applied in the studies. This makes the method increasingly more widely used around the world. But work based on dendrogeomorphology has not been reported in China. In this article, we reviewed the development of the study on flash floods based on tree ring, briefly summarized the research progress, and discussed the advantages, limitations, and potential of this approach, so as to provide some reference information for relevant work in China.

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Post-event analysis and flash flood hydrology in Slovakia

Journal of Hydrology and Hydromechanics ◽

10.1515/johh-2016-0041 ◽

2016 ◽

Vol 64 (4) ◽

pp. 304-315 ◽

Cited By ~ 8

Author(s):

Kamila Hlavčová ◽

Silvia Kohnová ◽

Marco Borga ◽

Oliver Horvát ◽

Pavel Šťastný ◽

...

Keyword(s):

Hydrological Model ◽

Flash Flood ◽

Flash Floods ◽

Event Analysis ◽

Distributed Hydrological Model ◽

Rainfall Runoff ◽

Flood Events ◽

Spatially Distributed ◽

Catchment Size ◽

Flood Peaks

Abstract This work examines the main features of the flash flood regime in Central Europe as revealed by an analysis of flash floods that have occurred in Slovakia. The work is organized into the following two parts: The first part focuses on estimating the rainfall-runoff relationships for 3 major flash flood events, which were among the most severe events since 1998 and caused a loss of lives and a large amount of damage. The selected flash floods occurred on the 20th of July, 1998, in the Malá Svinka and Dubovický Creek basins; the 24th of July, 2001, at Štrbský Creek; and the 19th of June, 2004, at Turniansky Creek. The analysis aims to assess the flash flood peaks and rainfall-runoff properties by combining post-flood surveys and the application of hydrological and hydraulic post-event analyses. Next, a spatially-distributed hydrological model based on the availability of the raster information of the landscape’s topography, soil and vegetation properties, and rainfall data was used to simulate the runoff. The results from the application of the distributed hydrological model were used to analyse the consistency of the surveyed peak discharges with respect to the estimated rainfall properties and drainage basins. In the second part these data were combined with observations from flash flood events which were observed during the last 100 years and are focused on an analysis of the relationship between the flood peaks and the catchment area. The envelope curve was shown to exhibit a more pronounced decrease with the catchment size with respect to other flash flood relationships found in the Mediterranean region. The differences between the two relationships mainly reflect changes in the coverage of the storm sizes and hydrological characteristics between the two regions.

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Effectiveness of the Submersible Embankment in Haor Area in Bangladesh

Journal of Disaster Research ◽

10.20965/jdr.2018.p0780 ◽

2018 ◽

Vol 13 (4) ◽

pp. 780-792

Author(s):

Mohammad Hossain Mahtab ◽

Miho Ohara ◽

Mohamed Rasmy ◽

◽

Keyword(s):

Flash Flood ◽

Flash Floods ◽

Rainfall Runoff ◽

Flood Events ◽

Monsoon Period ◽

Flash Flooding ◽

The North ◽

North Eastern ◽

Embankment Height ◽

North Eastern Part

The north-eastern part of Bangladesh is very productive for agriculture and fishing, and the region involves several depressed (haor) areas. Flash floods during the pre-monsoon period bring devastating damage to agriculture in the haor region recurrently. To protect crops from flash floods, the Bangladesh Water Development Board constructed several ring-type submersible embankments. In this research, we have investigated the effectiveness of submersible embankments in controlling flash flooding in the Matian and Shanir haors in the Sunamganj district. A two-dimensional rainfall runoff inundation model was applied considering several scenarios for simulating heavy flash flood events in 2004, 2010, and 2016. Without an embankment, the river overflow would have entered the Matian haor 3 days, 22 days, and 9 days earlier in 2004, 2010, and 2016, respectively, whereas it would have been 7 days and 23 days earlier in 2004 and 2010 for the Shanir haor. The event in 2016 was successfully stopped by the Shanir haor embankment. To avoid river overflow entering into the Matian and Shanir haor completely, the embankment height must be elevated further by 1 m and 0.7 m, respectively. Providing proper drainage facilities for the accumulated rain water inside the hoar is still an important issue for protecting the crops effectively.

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Impact of Flash Flood Events on the Coastal Waters Around Madeira Island: The “Land Mass Effect”

Frontiers in Marine Science ◽

10.3389/fmars.2021.749638 ◽

2022 ◽

Vol 8 ◽

Author(s):

Alexandra Rosa ◽

Cláudio Cardoso ◽

Rui Vieira ◽

Ricardo Faria ◽

Ana R. Oliveira ◽

...

Keyword(s):

Chlorophyll A ◽

Coastal Waters ◽

Flash Flood ◽

Mass Effect ◽

Flash Floods ◽

River Plume ◽

Flood Events ◽

Madeira Island ◽

The Impact ◽

Land Runoff

The Island Mass Effect has been primarily attributed to nutrient enhancement of waters surrounding oceanic islands due to physical processes, whereas the role of land runoff has seldom been considered. Land runoff can be particularly relevant in mountainous islands, highly susceptible to torrential rainfall that rapidly leads to flash floods. Madeira Island, located in the Northeast Atlantic Ocean, is historically known for its flash flood events, when steep streams transport high volumes of water and terrigenous material downstream. A 22-year analysis of satellite data revealed that a recent catastrophic flash flood (20 February 2010) was responsible for the most significant concentration of non-algal Suspended Particulate Matter (SPM) and Chlorophyll-a at the coast. In this context, our study aims to understand the impact of the February 2010 flash flood events on coastal waters, by assessing the impact of spatial and temporal variability of wind, precipitation, and river discharges. Two specific flash floods events are investigated in detail (2 and 20 February 2010), which coincided with northeasterly and southwesterly winds, respectively. Given the lack of in situ data documenting these events, a coupled air-sea-land numerical framework was used, including hydrological modeling. The dynamics of the modeled river plumes induced by flash floods were strongly influenced by the wind regimes subsequently affecting coastal circulation, which may help to explain the differences between observed SPM and Chlorophyll-a distributions. Model simulations showed that during northeasterly winds, coastal confinement of the buoyant river plume persisted on the island’s north coast, preventing offshore transport of SPM. This mechanism may have contributed to favorable conditions for phytoplankton growth, as captured by satellite-derived Chlorophyll-a in the northeastern coastal waters. On the island’s south coast, strong ocean currents generated in the eastern island flank promoted strong vertical shear, contributing to vertical mixing. During southwesterly winds, coastal confinement of the plume with strong vertical density gradient was observed on the south side. The switch to eastward winds spread the south river plume offshore, forming a filament of high Chlorophyll-a extending 70 km offshore. Our framework demonstrates a novel methodology to investigate ocean productivity around remote islands with sparse or absent field observations.

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From Flash Flood Vulnerability and Risk Assessment to Property Damage Prediction: the Value of Machine Learning

10.5194/egusphere-egu2020-19057 ◽

2020 ◽

Author(s):

Atieh Alipour ◽

Peyman Abbaszadeh ◽

Ali Ahmadalipour ◽

Hamid Moradkhani

Keyword(s):

Machine Learning ◽

Flash Flood ◽

Rapid Onset ◽

Flash Floods ◽

Flood Damage ◽

Flood Events ◽

Property Damage ◽

Damage Prediction ◽

Financial Consequences

Flash floods, as a result of frequent torrential rainfalls caused by tropical storms, thunderstorms, and hurricanes, are a prevalent natural disaster in the southeast U.S. (SEUS), which frequently threaten human lives and properties in the region. According to the U.S. National Weather Service (NWS), flash floods generally initiate within less than six hours of an intense rainfall onset. Therefore, there is a limited chance for effective and timely decision-making. Due to the rapid onset of flash floods, they are costly events, such that only during 1996 to 2017 flash floods imposed 7.5 billion dollars property damage to the SEUS. Therefore, estimating the potential economic damages as a result of flash floods are crucial for flood risk management and financial appraisals for decision makers. A multitude of studies have focused on flood damage modeling, few of which investigated the issue on a large domain. Here, we propose a systematic framework that considers a variety of factors that explain different risk components (i.e., hazard, vulnerability, and exposure) and leverages Machine Learning (ML) for flood damage prediction. Over 14,000 flash flood events during 1996 to 2017 were assessed to analyze their characteristics including frequency, duration, and intensity. Also, different data sources were utilized to derive information related to each event. The most influential features are then selected using a multi criteria variable selection approach. Then, the ML model is implemented for not only binary classification of damage (i.e., whether a flash flood event caused any damage or not), but also for developing a model to predict the financial consequences associated with flash flood events. The results indicate a high accuracy for the classifier, significant correlation and relatively low bias between the predicted and observed property damages showing the effectiveness of proposed methodology for flash flood damage modeling applicable to variety of flood prone regions.

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Bias Correction of Satellite-Based Rainfall Estimates for Modeling Flash Floods in Semi-Arid regions: Application to Karpuz River, Turkey

10.5194/nhess-2016-339 ◽

2016 ◽

Cited By ~ 7

Author(s):

Mohamed Saber ◽

Koray Yilmaz

Keyword(s):

Bias Correction ◽

Flash Flood ◽

Flash Floods ◽

Rainfall Rate ◽

Assessment Model ◽

Model Parameters ◽

Flood Events ◽

Rain Gauges ◽

Semi Arid ◽

Rainfall Estimates

Abstract. This study investigates the utility of gauge-corrected satellite-based rainfall estimates in simulating flash floods at Karpuz River - a semi-arid basin in Turkey. Global Satellite Mapping of Precipitation (GSMaP) product was evaluated with the rain gauge network at monthly and daily time-scales considering various time periods and rainfall rate thresholds. Statistical analysis indicated that GSMaP shows acceptable linear correlation coefficient with rain gauges however suffers from significant underestimation bias. A rainfall rate threshold of 1 mm/month was the best choice to improve the match between GSMaP and rain gauges implying that appropriate threshold selection is critically important for the bias correction. Multiplicative bias correction was applied to GSMaP data using the bias factors calculated between GSMaP and observed rainfall. Hydrological River Basin Environmental Assessment Model (Hydro-BEAM) was used to simulate flash floods at the hourly time scale driven by the corrected GSMaP rainfall data. The model parameters were calibrated for flash flood events during October-December 2007 and then validated for flash flood events during October-December 2009. The results show that the simulated surface runoff hydrographs reasonably coincide with the observed hydrographs.

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More frequent flash flood events and extreme precipitation favouring atmospheric conditions in temperate regions of Europe

10.5194/hess-2021-628 ◽

2021 ◽

Author(s):

Judith Meyer ◽

Malte Neuper ◽

Luca Mathias ◽

Erwin Zehe ◽

Laurent Pfister

Keyword(s):

Extreme Precipitation ◽

Western Europe ◽

Flash Flood ◽

Flash Floods ◽

Water Levels ◽

Specific Humidity ◽

Atmospheric Conditions ◽

Flood Events ◽

Extreme Precipitation Events ◽

Precipitation Events

Abstract. In recent years, flash floods repeatedly occurred in temperate regions of central western Europe. Unlike in Mediterranean catchments, this flooding behaviour is unusual. In the past, and especially in the 1990s, floods were characterized by predictable, slowly rising water levels during winter and driven by westerly atmospheric fluxes (Pfister et al., 2004). The intention of this study is to link the recent occurrence of flash floods in central western Europe to extreme precipitation and specific atmospheric conditions to identify the cause for this apparent shift. Therefore, we hypothesise that an increase in extreme precipitation events has subsequently led to an increase in the occurrence of flash flood events in central western Europe and all that being caused by a change in the occurrence of flash flood favouring atmospheric conditions. To test this hypothesis, we compiled data on flash floods in central western Europe and selected precipitation events above 40 mm h−1 from radar data (RADOLAN, DWD). Moreover, we identified proxy parameters representative for flash flood favouring atmospheric conditions from the ERA5 reanalysis dataset. High specific humidity in the lower troposphere (q ≥ 0.004 kg kg−1), sufficient latent instability (CAPE ≥ 100 J kg−1) and weak deep-layer wind shear (DLS ≤ 10 m s−1) proved to be characteristic for long-lasting intense rainfall that can potentially trigger flash floods. These atmospheric parameters, as well as the flash flood and precipitation events were then analysed using linear models. Thereby we found significant increases in atmospheric moisture contents and increases in atmospheric instability. Parameters representing the motion and organisation of convective systems occurred slightly more often or remained unchanged in the time period from 1981–2020. Moreover, a trend in the occurrence of flash floods was confirmed. The number of precipitation events, their maximum 5-minute intensities as well as their hourly sums were however characterized by large inter-annual variations and no trends could be identified between 2002–2020. This study therefore shows that the link from atmospheric conditions via precipitation to flash floods cannot be traced down in an isolated way. The complexity of interactions is likely higher and future analyses should include other potentially relevant factors such as intra-annual precipitation patterns or catchment specific parameters.

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Identifying and linking flash flood prone atmospheric conditions to flooding occurrences in central Western Europe

10.5194/egusphere-egu21-12522 ◽

2021 ◽

Author(s):

Judith Meyer ◽

Audrey Douinot ◽

Malte Neuper ◽

Luca Mathias ◽

Carol Tamez-Meléndez ◽

...

Keyword(s):

River Basin ◽

Western Europe ◽

Flash Flood ◽

Flash Floods ◽

Precipitation Data ◽

Atmospheric Conditions ◽

Flood Events ◽

Atmospheric Parameters ◽

Circulation Patterns ◽

Daily Precipitation Data

In recent years, flash floods occurred repeatedly in temperate regions of central Western Europe (e.g., Orlacher Bach (GER), Hupselsebeek (NL), White Ernz (LUX)). This type of extreme flood events is unusual for these regions, as opposed to Mediterranean catchments that are more prone to flash floods. In the second half of the 20th century, and more specifically in the 1990&#8217;s, westerly atmospheric fluxes were the dominating triggering factor of large scale (winter) floods in central Western Europe.With a view to gain a better understanding of the mechanisms controlling the recent flash flood events at higher latitudes, we explore various avenues related to the non-stationarity of environmental systems. We hypothesize that an increase in the occurrence of flash flood prone atmospheric conditions has recently led to higher precipitation totals and a subsequent increase in flash flood events in central Western Europe.Therefore, we first analysed relevant atmospheric parameters from the ERA 5 reanalysis dataset. Second, we linked the atmospheric parameters to the concept of general circulation patterns as per Hess and Brezowsky (1977). Third, we analysed precipitation data from a set of stations located in the Moselle river basin (35.000 km2). These three pillars build the base for identifying flash flood prone atmospheric conditions over space and time that are then compared to actual occurrences of extreme discharge events in streams within the Moselle river basin.To validate our hypothesis, spatial and temporal patterns in the occurrence of extreme precipitation and discharge events need to match atmospheric patterns. Preliminary results suggest that daily precipitation data and meridional circulation patterns do not show a clear trend towards an increased occurrence of precipitation events or higher precipitation amounts. Due to the limitations inherent to the available long-term dataset of daily data, the hypothesis can only be partly evaluated, and more detailed analyses are added. For that reason, discharge data with a 15-minute resolution, along with precipitation radar data of 5-minute time steps will be employed at a limited spatial extent in future analyses. In case of rejection of our working hypothesis this may pinpoint to other flash flood triggering mechanisms, such as changes in land use, soil moisture conditions or cultivation methods.

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Tree-ring derived millennial precipitation record for the south-central Tibetan Plateau and its possible driving mechanism

The Holocene ◽

10.1177/0959683612450198 ◽

2012 ◽

Vol 23 (1) ◽

pp. 36-45 ◽

Cited By ~ 30

Author(s):

Minhui He ◽

Bao Yang ◽

Achim Bräuning ◽

Jianglin Wang ◽

Zhangyong Wang

Keyword(s):

Tibetan Plateau ◽

Tree Ring ◽

Rainfall Variability ◽

Ring Width ◽

Driving Mechanism ◽

Tree Ring Width ◽

The South ◽

South Central ◽

Central Tibetan Plateau ◽

Precipitation Record

Knowledge of Asian monsoon variability remains limited because of sparse instrumental data available only for short time series. Here, an updated tree-ring width record covering the period ad 1037–2009 was developed for the south-central Tibetan Plateau (TP). Correlation analysis revealed a significant relationship ( r = 0.71) between the tree-ring index and annual (previous July to current June) precipitation series for the instrumental period 1963–2008, which accounts for 50.41% of the rainfall variability. Based on a linear regression model, the longest available regional precipitation history was reconstructed. Spatial correlation between tree ring width and annual precipitation data from previous July to current June indicates that the reconstruction is representative of precipitation changes on the south-central TP. Regional wet conditions occurred during ad 1095–1161, 1376–1403, 1414–1446, 1518–1537, 1549–1572, 1702–1757, 1848–1878 and 1891–1913, while dry periods were identified during ad1189–1242, 1256–1314, 1329–1357, 1470–1491, 1573–1623, 1636–1686, 1761–1821, 1823–1847, 1879–1890 and 1931–1985. The negative correlation between our reconstructed precipitation and India monsoon rainfall series indicates the seesaw pattern over northern and southern monsoon Asia. It is suggested that solar radiation-induced sea surface temperature (SST) anomalies over the tropical Pacific influence regional rainfall patterns. The degree of this influence has been stable at the multidecadal scale during the past 1000 years.

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floodX: Urban flash flood experiments monitored with conventional and alternative sensors

10.5194/essd-2017-7 ◽

2017 ◽

Author(s):

Matthew Moy de Vitry ◽

Simon Dicht ◽

João P. Leitão

Keyword(s):

Urban Areas ◽

Flash Flood ◽

Well Being ◽

Early Warning Systems ◽

Flash Floods ◽

Lessons Learned ◽

High Temporal Resolution ◽

Data Types ◽

Urban Flood ◽

Flood Risk Mapping

Abstract. The datasets described in this paper are intended to provide a basis on which new methods for monitoring and modelling urban pluvial flash floods can be developed. Pluvial flash floods are a growing hazard to property and inhabitants' well-being in urban areas. However, the lack of appropriate data collection methods is often cited as an impediment for reliable flood modelling, thereby hindering the improvement of flood risk mapping and early warning systems. In the floodX project, 37 controlled urban flash floods were generated and monitored in a flood response training facility with state-of-the-art conventional sensors in the drainage network, as well as alternative sensors on the surface, namely temperature probes and surveillance cameras. With these data, the technical feasibility of utilizing citizen science and computer vision for urban flood monitoring can be explored. The floodX project stands out as the largest documented flood experiment of its kind, providing both conventional and alternative data types in parallel and at high temporal resolution. Besides describing the flash flood experiments and the resulting datasets, weaknesses in the data and lessons learned are also described. The main data package is openly available at http://doi.org/10.5281/zenodo.236878.

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Characterization of physically based hydrologic model behaviour with temporal sensitivity analysis for flash floods in Mediterranean catchments

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-10-1375-2013 ◽

2013 ◽

Vol 10 (1) ◽

pp. 1375-1422

Author(s):

P. A. Garambois ◽

H. Roux ◽

K. Larnier ◽

W. Castaings ◽

D. Dartus

Keyword(s):

Sensitivity Analysis ◽

Flash Flood ◽

Soil Depth ◽

Flash Floods ◽

Hydrologic Model ◽

Valuable Insight ◽

Model Output ◽

Flood Events ◽

Extreme Flood ◽

Physically Based

Abstract. This paper presents a detailed analysis of 10 flash flood events in the Mediterranean region using the distributed hydrological model MARINE. Characterizing catchment's response during flash flood events may provide a new and valuable insight into the processes involved for extreme flood response and their dependency on catchment properties and flood severity. The main objective of this study is to analyze hydrologic model sensitivity in the case of flash floods with a new approach in hydrology, allowing model outputs variance decomposition for temporal patterns of parameter sensitivity analysis. Such approaches enable ranking of uncertainty sources for non-linear and non-monotonic mappings with a low computational cost. This study uses hydrologic model and sensitivity analysis as learning tools to derive temporal sensitivity analysis with a variance based method in the case of 10 flash floods that occurred in the French Pyrenees and Cévennes foothills. This constitutes a huge dataset given the scarcity of data about flash flood events. With Nash performances above 0.73 on average for this extended set of validation events, the five sensitive parameters of MARINE distributed physically based model are analyzed. This contribution shows that soil depth explains more than 80% of model output variance when most hydrographs are peaking. Moreover the lateral subsurface transfer is responsible for 80% of model variance for some catchment-flood events' hydrographs during slow declining limbs. The unexplained variance of model output representing interactions between parameters reveals to be very low during modeled flood peaks and informs that model parsimonious parameterization is appropriate to tackle the problem of flash floods. Interactions observed after model initialization or rainfall intensity peaks incite to improve water partition representation between flow components and initialization itself. This paper gives a practical framework for application of this method to other models, landscapes and climatic conditions, potentially helping to improve processes understanding and representation.

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