scholarly journals The Spatiotemporal Distribution of Flash Floods and Analysis of Partition Driving Forces in Yunnan Province

2019 ◽  
Vol 11 (10) ◽  
pp. 2926 ◽  
Author(s):  
Junnan Xiong ◽  
Chongchong Ye ◽  
Weiming Cheng ◽  
Liang Guo ◽  
Chenghu Zhou ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Economic Development ◽  
Return Period ◽  
Driving Forces ◽  
Flash Flood ◽  
Temporal Distribution ◽  
Heavy Precipitation ◽  
Spatiotemporal Analysis ◽  
Flash Floods

Flash floods are one of the most serious natural disasters, and have a significant impact on economic development. In this study, we employed the spatiotemporal analysis method to measure the spatial–temporal distribution of flash floods and examined the relationship between flash floods and driving factors in different subregions of landcover. Furthermore, we analyzed the response of flash floods on the economic development by sensitivity analysis. The results indicated that the number of flash floods occurring annually increased gradually from 1949 to 2015, and regions with a high quantity of flash floods were concentrated in Zhaotong, Qujing, Kunming, Yuxi, Chuxiong, Dali, and Baoshan. Specifically, precipitation and elevation had a more significant effect on flash floods in the settlement than in other subregions, with a high r (Pearson’s correlation coefficient) value of 0.675, 0.674, 0.593, 0.519, and 0.395 for the 10 min precipitation in 20-year return period, elevation, 60 min precipitation in 20-year return period, 24 h precipitation in 20-year return period, and 6 h precipitation in 20-year return period, respectively. The sensitivity analysis showed that the Kunming had the highest sensitivity (S = 21.86) during 2000–2005. Based on the research results, we should focus on heavy precipitation events for flash flood prevention and forecasting in the short term; but human activities and ecosystem vulnerability should be controlled over the long term.

scholarly journals Spatial–temporal characteristics and driving factors of flash floods in Shaanxi Province considering regional differentiation

2021 ◽  
Author(s):  
Han Zhang ◽  
Jungang Luo ◽  
Jingyan Wu ◽  
Mengjie Yu
Keyword(s):  
Driving Forces ◽  
Flash Flood ◽  
Temporal Distribution ◽  
Flash Floods ◽  
Shaanxi Province ◽  
Regional Differentiation ◽  
Effective Prevention ◽  
Temporal Characteristics ◽  
Northern Shaanxi ◽  
And Control

Abstract Flash floods show strong regional differentiation in spatial–temporal distribution and driving forces, thereby hindering their effective prevention and control. This study analyzed the spatiotemporal characteristics of flash floods in Shaanxi Province, China, differentiated among the northern Shaanxi (NS), Guanzhong (GZ), and southern Shaanxi (SS) regions based on the Mann–Kendall, Theil–Sen Median, and standard deviation ellipse methods. The main factors driving disasters and their interactions in each region were then identified within the three categories of precipitation factor (PPF), surface environment factor, and human activity factor (HAF) based on a geographical detector. Finally, the differences in flash flood characteristics among the NS, GZ, and SS regions were analyzed. The results showed that flash floods in Shaanxi Province are greatly affected by the PPF and the HAF, although the spatial–temporal characteristics and disaster-causing factors were significantly different in each region. The regions were ranked according to the number and growth trends of flash floods as follows: SS > GZ > NS. Furthermore, flash floods were affected by multiple factors, with the interaction between factors acting as a driving force of flash floods. The results of this study can provide a reference for the management of flash floods under regional differentiation.

scholarly journals Spatiotemporal Characteristics and Driving Force Analysis of Flash Floods in Fujian Province

2020 ◽  
Vol 9 (2) ◽  
pp. 133 ◽  
Author(s):  
Junnan Xiong ◽  
Quan Pang ◽  
Chunkun Fan ◽  
Weiming Cheng ◽  
Chongchong Ye ◽  
...  
Keyword(s):  
Driving Forces ◽  
Flash Flood ◽  
Principal Component ◽  
Flash Floods ◽  
Fujian Province ◽  
Spatiotemporal Characteristics ◽  
Middle Mountains ◽  
Driving Force Analysis ◽  
Economic Development Model ◽  
The Impact

Flash floods are one of the most destructive natural disasters. The comprehensive identification of the spatiotemporal characteristics and driving factors of a flash flood is the basis for the scientific understanding of the formation mechanism and the distribution characteristics of flash floods. In this study, we explored the spatiotemporal patterns of flash floods in Fujian Province from 1951 to 2015. Then, we analyzed the driving forces of flash floods in geomorphic regions with three different grades based on three methods, namely, geographical detector, principal component analysis, and multiple linear regression. Finally, the sensitivity of flash floods to the gross domestic product, village point density, annual maximum one-day precipitation (Rx1day), and annual total precipitation from days > 95th percentile (R95p) was analyzed. The analytical results indicated that (1) The counts of flash floods rose sharply from 1988, and the spatial distribution of flash floods mainly extended from the coastal low mountains, hills, and plain regions of Fujian (IIA2) to the low-middle mountains, hills, and valley regions in the Wuyi mountains (IIA4) from 1951 to 2015. (2) From IIA2 to IIA4, the impact of human activities on flash floods was gradually weakened, while the contribution of precipitation indicators gradually strengthened. (3) The sensitivity analysis results revealed that the hazard factors of flash floods in different periods and regions had significant differences in Fujian Province. Based on the above results, it is necessary to accurately forecast extreme precipitation and improve the economic development model of the IIA2 region.

scholarly journals The 20 February 2010 Madeira flash-floods: synoptic analysis and extreme rainfall assessment

2012 ◽  
Vol 12 (3) ◽  
pp. 715-730 ◽  
Author(s):  
M. Fragoso ◽  
R. M. Trigo ◽  
J. G. Pinto ◽  
S. Lopes ◽  
A. Lopes ◽  
...  
Keyword(s):  
Return Period ◽  
Flash Flood ◽  
Deep Convection ◽  
Extreme Rainfall ◽  
Flash Floods ◽  
Rain Gauge ◽  
Reanalysis Data ◽  
Sources Of Information ◽  
Precipitation Records ◽  
Flood Dynamics

Abstract. This study aims to characterise the rainfall exceptionality and the meteorological context of the 20 February 2010 flash-floods in Madeira (Portugal). Daily and hourly precipitation records from the available rain-gauge station networks are evaluated in order to reconstitute the temporal evolution of the rainstorm, as its geographic incidence, contributing to understand the flash-flood dynamics and the type and spatial distribution of the associated impacts. The exceptionality of the rainstorm is further confirmed by the return period associated with the daily precipitation registered at the two long-term record stations, with 146.9 mm observed in the city of Funchal and 333.8 mm on the mountain top, corresponding to an estimated return period of approximately 290 yr and 90 yr, respectively. Furthermore, the synoptic associated situation responsible for the flash-floods is analysed using different sources of information, e.g., weather charts, reanalysis data, Meteosat images and radiosounding data, with the focus on two main issues: (1) the dynamical conditions that promoted such anomalous humidity availability over the Madeira region on 20 February 2010 and (2) the uplift mechanism that induced deep convection activity.

scholarly journals A Spatiotemporal Analysis of Historical Droughts in Korea

2011 ◽  
Vol 50 (9) ◽  
pp. 1895-1912 ◽  
Author(s):  
Do-Woo Kim ◽  
Hi-Ryong Byun ◽  
Ki-Seon Choi ◽  
Su-Bin Oh
Keyword(s):  
South Korea ◽  
Return Period ◽  
Summer Rainfall ◽  
Hierarchical Cluster ◽  
Spatiotemporal Analysis ◽  
Dry Season ◽  
Coastal Regions ◽  
Drought Intensity ◽  
Daily Precipitation Data

AbstractThe climatological characteristics of drought in South Korea were investigated using daily precipitation data for 1777–2008. The effective drought index was used to quantify the drought intensity. As a result, five characteristics were discovered. First, South Korea can be divided into four drought subregions (the central, southern, and east coastal regions and Jeju Island) using hierarchical cluster analysis. Second, a map for long-term drought conditions in the four subregions is created that allows identification of the spatiotemporal distribution of droughts for the 231 yr at a glance. Third, droughts in South Korea have time scales that depend on the onset season. Spring (March–May) droughts tend to be short (≤200 days) because the summer (June–September) rainy season follows. Summer droughts tend to be long (>200 days) because the dry season (October–February) follows. In the dry season, droughts tend to be sustained or become severe rather than being initiated or relieved. Fourth, 5-, 14-, 34-, and 115-yr drought cycles were identified by spectral analysis. The 5-yr cycle was dominant in all of the regions, the 14-yr cycle was observed over the southern and east coastal regions, and the 34-yr cycle was observed over the central region. Fifth, the most extreme drought occurred in 1897–1903 (return period: 233 yr) and was associated with the 115-yr drought cycle. After this drought, severe droughts (return period of >10 yr) occurred in 1927–30, 1938–40, 1942–45, 1951–52, 1967–69, and 1994–96; they were caused by the consecutive shortage of summer rainfall for two or more years.

scholarly journals A Temporally Varied Rainfall Simulator for Flash Flood Studies

2021 ◽  
pp. 267-279
Author(s):  
Mohammad Ebrahim Banihabib ◽  
Bahman Vaziri
Keyword(s):  
Numerical Model ◽  
Flash Flood ◽  
Experimental Studies ◽  
Temporal Distribution ◽  
Field Studies ◽  
Flash Floods ◽  
Flash Flooding ◽  
Rainfall Simulator ◽  
Natural Rainfall ◽  
Precipitation Events

AbstractExperimental studies of flash floods require rainfall simulations. For this reason, various rainfall simulators have been designed, built, and employed in previous studies. These previous rainfall simulators have provided good simulations of constant rainfall intensities; however, these simulators cannot generate temporally varied rainstorms. Thus, the effect of the temporal distribution of a rainstorm on flash flooding cannot be studied using current rainfall simulators. To achieve accurate and reliable results in flash flood studies, simulating rainstorms that are similar to natural precipitation events is essential, and natural rainfall varies temporally. Thus, a rainstorm simulator was designed and built using cascading tanks to generate rainstorm hyetographs that cannot be obtained using traditional rainfall simulators. The result of the rainstorm generated by the proposed instrument and its numerical model showed that the instrument can simulate the temporal distributions of rainstorms with an accuracy of 95 percent. Consequently, the proposed instrument and its numerical model can be applied for generating artificial rainstorm hyetographs in experimental and field studies of flash floods.

Which event produces the largest flash flood? Considering rainfall characteristics, initial soil moisture, retention and run-on infiltration

2020 ◽  
Author(s):  
Markus Weiler ◽  
Hannes Leistert ◽  
Andreas Steinbrich
Keyword(s):  
Soil Moisture ◽  
Return Period ◽  
Overland Flow ◽  
Flash Flood ◽  
Joint Probability ◽  
Flash Floods ◽  
Runoff Generation ◽  
Runoff Formation ◽  
Initial Soil Moisture ◽  
Initial Soil

<p>Local heavy precipitation regularly causes great damage resulting from flash floods in small catchments. Appropriate discharge records are usually unavailable to derive an extreme value statistics and regionalization approaches predicting peak discharge from discharge records of larger basins cannot consider the small-scale effects and local processes. In addition, forecasting flash floods from rainfall forecast requires to identify the event conditions under which a catchment is most prone to trigger flash floods. Therefore, factors influencing runoff formation and concentration need to be identified based on catchment characteristics in order to predict flood hydrographs, geomorphic processes and flood inundation.</p><p>We have developed a framework depending on the joint probability of soil moisture and rainfall and used the distributed, processed-based rainfall-runoff model RoGeR to predict the spatial explicit probability of soil moisture and linking this to overland-flow and subsurface flow generation assuming different scenarios of soil moisture and rainfall characteristics. Selected combinations result in a joint probability with a specified return period (e.g. 100 year), but are based on different probabilities for rainfall amount, duration and initial soil moisture. From this, the combination of a precipitation event and initial soil moisture condition can be determined which generates the largest runoff generation. In addition, we found, that accounting for the spatially and temporally controlled superimposition of runoff formation and runoff concentration, including the possible infiltration of overland flow (run-on infiltration) along the flow path and the retention in depression can have considerable influence on modelled peak discharge and discharge volume for a given catchment. For this purpose, various methods were developed and tested considering the effects of run-on infiltration and retention, from complex 2D hydraulic models coupled with RoGeR to simpler approaches considering run-on infiltration only locally or based on the difference between actual and potential infiltration. These approaches were tested in different catchments with different soils, geologies and land use. Also, the sensitiviy of surface roughness was considered.</p><p>We developed an interactive spatial explicit method, which combines the joint probability of soil moisture and rainfall for runoff formation with hydraulic assumptions to determine runoff concentration and thus the corresponding design hydrographs and the specific conditions a catchment can trigger flash floods. This information can on the one side help to generate flash flood risk maps, but should also be considered in order to provide adequate catchment specific information for heavy precipitation risk management. We could clearly demonstrate that only the combined consideration of factors affecting flood formation and concentration and its implementation into a statistical framework allows to predict floods for a specific return period (which is not equal to the return period of precipitation) for small catchments where different runoff generation mechanisms occur simultaneously.</p>

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

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.

scholarly journals Lightning and rain dynamic indices as predictors for flash floods events in the Mediterranean

2010 ◽  
Vol 23 ◽  
pp. 57-64 ◽  
Author(s):  
N. Harats ◽  
B. Ziv ◽  
Y. Yair ◽  
V. Kotroni ◽  
U. Dayan
Keyword(s):  
Flash Flood ◽  
Heavy Precipitation ◽  
Flash Floods ◽  
Lightning Activity ◽  
Specific Humidity ◽  
Flood Events ◽  
Funded Project ◽  
The Mediterranean ◽  
Good Concordance ◽  
Short Term Forecasting

Abstract. The FLASH EU funded project aims to observe, analyze and model lightning activity in thunderstorms for use in short term forecasting of flash floods in the Mediterranean region. Two new indices, aimed to assess the potential for heavy precipitation and flash-floods, are proposed and evaluated. The first is a lightning index – the MKI, which is a modified version of the KI-index. The applied index gives more weight to the lower- and mid-level relative humidity. The second is a new rain index, the RDI, which is the integrated product of specific humidity and vertical velocity. With the aim to contribute to the aforementioned objectives, 3 flash flood events, two in Israel and one in Greece are analyzed in the present study, using the 2 proposed indices. The NCEP/NCAR reanalysis database, of 2.5°×2.5° resolution, failed to resolve the meso-scale features of the observed flash flood events. Therefore, the ECWMF database, of 0.5°×0.5° resolution, was used for calculating and displaying the two indices. Comparison between the observed rain and lightning and the respective indices for the two pieces of data was performed for the flash flood events. The results show good concordance of both indices with timing and spatial distribution in 2 of them, while in one of them is displaced by more than 50 km. The good agreement in locating the maximum between the MKI and RDI suggests that the proposed indices are good predictors for both intense lightning activity and torrential rain and consequently, for potential flash floods.

Workshop 2 (synthesis): driving forces and incentives for change towards sustainable water development

2002 ◽  
Vol 45 (8) ◽  
pp. 141-144 ◽  
Author(s):  
K. Takahashi ◽  
M. de los Angeles ◽  
J. Kuylenstierna
Keyword(s):  
Economic Development ◽  
Carrying Capacity ◽  
Water Policy ◽  
Life Support ◽  
Driving Forces ◽  
Management Strategies ◽  
Policy Makers ◽  
Key Points ◽  
Social And Economic Development

Water is a key resource in attaining sustainability – in social and economic development as well as in the long-term carrying capacity of the planet's life support systems, but consensus on the meaning and priority of these terms is still needed. Amongst the key points identified for water professionals: it is necessary to challenge compartmentalisation in water policy and management; water management strategies must focus clearly on the interdependence of the environment and socio-economic development; water professionals have a key role but must package the information and insight they can provide in a way that is attractive to intended recipients such as policy makers.

scholarly journals Characterization of process-oriented hydrologic model behavior with temporal sensitivity analysis for flash floods in Mediterranean catchments

2013 ◽  
Vol 17 (6) ◽  
pp. 2305-2322 ◽  
Author(s):  
P. A. Garambois ◽  
H. Roux ◽  
K. Larnier ◽  
W. Castaings ◽  
D. Dartus
Keyword(s):  
Sensitivity Analysis ◽  
Flash Flood ◽  
Soil Depth ◽  
Computational Cost ◽  
Flash Floods ◽  
Hydrologic Model ◽  
Valuable Insight ◽  
Model Output ◽  
Flood Events ◽  
Process Oriented

Abstract. This paper presents a detailed analysis of 10 flash flood events in the Mediterranean region using the distributed hydrological model MARINE. Characterizing catchment response during flash flood events may provide new and valuable insight into the dynamics involved for extreme catchment response and their dependency on physiographic properties and flood severity. The main objective of this study is to analyze flash-flood-dedicated hydrologic model sensitivity 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 nonlinear and nonmonotonic mappings with a low computational cost. Hydrologic model and sensitivity analysis are used as learning tools on a large flash flood dataset. With Nash performances above 0.73 on average for this extended set of 10 validation events, the five sensitive parameters of MARINE process-oriented distributed 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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