scholarly journals Development of Korean Nomograms for Forecasting and Alerting Debris Flows Based on Critical Accumulated Rainfall

2019 ◽  
Author(s):  
Dong-Ho Nam ◽  
Suk-Ho Lee ◽  
Byung-Sik Kim
Keyword(s):  
South Korea ◽  
Urban Areas ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Short Term ◽  
Rainfall Events ◽  
Accumulated Rainfall ◽  
Landslides And Debris Flows ◽  
Climate Events ◽  
Heavy Rains

Ongoing climate change causes abnormal climate events worldwide such as increasing temperatures and changing rainfall patterns. With South Korea facing growing damage from the increased frequency of localized heavy rains, the country is not an exception. In particular, its steep slope lands, including mountainous areas, are vulnerable to damage from landslides and debris flows. In addition, localized short-term heavy rains that occur in urban areas with extremely high intensity tend to lead a sharp increase in damage from soil-related disasters and cause huge losses of life and property. Currently, South Korea predicts landslides and debris flows using the standards for forecasting landslides and heavy rains. However, as the forecasting is conducted separately for rainfall intensity and accumulated rainfall, this lacks a technique that reflects both amount and intensity of rainfall in an episode of localized heavy rainfall. This study, therefore, aims to develop such a technique by collecting past cases of debris flow occurrences and rainfall events that accompanied debris flows to calculate the rainfall triggering index (RTI) reflecting accumulated rainfall and rainfall intensity. In addition, the RTI is converted into the critical accumulated rainfall (Rc) to use precipitation information and provide real-time forecasting. The study classifies the standards for flow debris forecasting into three levels: ALERT (10%–50%), WARNING (50%–70%), and EMERGENCY (70% or higher), to provide a nomogram for 6 hr, 12 hr, and 24 hr. As a result of applying this classification into the actual cases of Seoul, Chuncheon, and Cheongju, it is found that about 2–4 hr of response time is secured from the point of the Emergency level to the occurrence of debris flows.

scholarly journals Development of Nomogram for Debris Flow Forecasting Based on Critical Accumulated Rainfall in South Korea

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2181
Author(s):  
Nam ◽  
Lee ◽  
Kim
Keyword(s):  
South Korea ◽  
Debris Flow ◽  
Urban Areas ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Extreme Weather Events ◽  
Weather Events ◽  
Accumulated Rainfall ◽  
Landslides And Debris Flows ◽  
Heavy Rains

Climate change causes extreme weather events worldwide such as increasing temperatures and changing rainfall patterns. With South Korea facing growing damage from the increased frequency of localized heavy rains. In particular, its steep slope lands, including mountainous areas, are vulnerable to damage from landslides and debris flows. In addition, localized short-term heavy rains that occur in urban areas with extremely high intensity tend to lead a sharp increase in damage from soil-related disasters and cause huge losses of life and property. Currently, South Korea forecasts landslides and debris flows using the standards for forecasting landslides and heavy rains. However, as the forecasting is conducted separately for rainfall intensity and accumulated rainfall, this lacks a technique that reflects both amount and intensity of rainfall in an episode of localized heavy rainfall. In this study, aims to develop such a technique by collecting past cases of debris flow occurrences and rainfall events that accompanied debris flows to calculate the rainfall triggering index (RTI) reflecting accumulated rainfall and rainfall intensity. In addition, the RTI is converted into the critical accumulated rainfall (Rc) to use rainfall information and provide real-time forecasting. The study classifies the standards for flow debris forecasting into three levels: ALERT (10–50%), WARNING (50–70%), and EMERGENCY (70% or higher), to provide a nomogram for 6 h, 12 h, and 24 h. As a result of applying this classification into the actual cases of Seoul, Chuncheon, and Cheongju, it is found that about 2–4 h of response time is secured from the point of the Emergency level to the occurrence of debris flows.

scholarly journals Rainfall events with shallow landslides in the Entella catchment (Liguria, Northern Italy)

2018 ◽  
Author(s):  
Anna Roccati ◽  
Francesco Faccini ◽  
Fabio Luino ◽  
Laura Turconi ◽  
Fausto Guzzetti
Keyword(s):  
River Basin ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Geographical Location ◽  
Early Warning Systems ◽  
Northern Italy ◽  
Shallow Landslides ◽  
Antecedent Rainfall ◽  
Rainfall Events ◽  
Landslides And Debris Flows

Abstract. In the recent decades, the Entella River basin, in the Liguria Apennines, Northern Italy, was hit by numerous intense rainfall events that triggered shallow landslides, soil slips and debris flows, causing casualties and extensive damage. We analysed landslides information obtained from different sources and rainfall data recorded in the period 2002–2016 by rain gauges scattered in the catchment, to identify the event rainfall duration, D (in h), and rainfall intensity, I (in mm h−1), that presumably caused the landslide events. Rainfall-induced landslides affected all the catchment area, but were most frequent and abundant in the central part, where the three most severe events hit on 24 November 2002, 21–22 October 2013, and 10 November 2014. Examining the timing and location of the failures, we found that the rainfall-induced landslides occurred primarily at the same time or within six hours from the maximum peak rainfall intensity, and at or near the geographical location where the rainfall intensity was largest. Adopting a Frequentist approach, we define the event rainfall intensity–event duration ID, threshold for the possible initiation of shallow landslides and debris flows in the Entella River basin. The threshold is lower than most of the thresholds proposed in the literature for similar mountain catchments, local areas and single regions in Italy. Analysis of the antecedent rainfall conditions for different periods, from 3 to 15 days, revealed that the antecedent rainfall did not play a significant role in the initiation of landslides in the Entella catchment. We expect that our findings will be useful in regional to local landslides early warning systems, and for land-planning aimed at reducing landslides risk in the study area.

Simulating debris flows triggered by rainfall in Shiyang gully, China

2020 ◽  
Author(s):  
Jiaoyang Li
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Intensity Increase ◽  
Short Term ◽  
Rain Area ◽  
Cumulative Rainfall ◽  
Event Flow ◽  
Warning Time ◽  
Main Factor

<p>A debris flow occurred in Shiyang gully, located between Hebei Province and Beijing, on 8 June 2017, resulting in 6 people dead or injured. Short-term heavy rainfall is the main factor that triggered this event, however, the meteorological agency didn’t forecast this event very well. In this study, numerical simulation using FLO-2D was performed to reproduce the debris flow event (flow depths, flow velocities, and sediment depositions)occurred in 2017. The results of the field survey showed that the influential range of debris flow is consistent with the simulation results. Simulated depth accuracy is greater than 70%. Then, we used FLO-2D is calibrated to simulate debris flows disasters under different rainfall scenarios. The results showed that, the Beijing needs to be warned when the accumulated precipitation is 40mm at the rainfall intensity of 1mm/min. As cumulative rainfall and rainfall intensity increase, the risk of Shiyang gully is increasing.  This study used FLO-2D simulated process of debris flows triggered by rainfall. The results showed the early warning time and influential range for different intensity ,accumulated precipitation, and rain area, which is beneficial to the debris flow management in the western mountainous areas of Beijing.</p>

Reconstruction of Past Erosional Force from Tree Ring Information around the Rokko Mountains, Japan

1990 ◽  
Vol 34 (2) ◽  
pp. 240-248 ◽  
Author(s):  
Kenji Kashiwaya ◽  
Takashi Okimura
Keyword(s):  
Tree Ring ◽  
Debris Flows ◽  
Ring Width ◽  
Tree Ring Width ◽  
Mountain Areas ◽  
Rainfall Events ◽  
The Past ◽  
The North ◽  
First Approximation ◽  
Landslides And Debris Flows

AbstractTorrential rainfalls in the Rokko Mountains have often triggered severe landslides and debris flows, but few such phenomena have occurred in the area just to the north of the mountains during the same rainfall events. The periodicity of 25–30 years in excess rainfall data (i.e., the annual summation of heavy rainfall of more than 100 mm/day during the past 100 years) around the mountains correlates with the increased frequency of landslides and debris flows. Analyses of tree-ring widths that span the past 50–240 years in samples taken from various areas in the mountains and the area just to the north indicate that most sequences have a dominant periodicity of about 25–30 years, the ring series in the mountain areas having a more conspicuous periodicity than those from the area just to the north. These results lead to the conclusion that excess rainfall may provide a first approximation of erosional force in areas affected by slope movement, and that tree-ring width may be used as a proxy for erosional force.

scholarly journals Ensembles of radar nowcasts and COSMO-DE-EPS for urban flood management

2018 ◽  
Vol 2017 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Alrun Jasper-Tönnies ◽  
Sandra Hellmers ◽  
Thomas Einfalt ◽  
Alexander Strehz ◽  
Peter Fröhle
Keyword(s):  
Urban Areas ◽  
Flood Management ◽  
Short Term ◽  
Ensemble Forecasts ◽  
Urban Flood ◽  
Rainfall Events ◽  
Flood Warning ◽  
Urban Catchments ◽  
Heavy Rainfall Events

Abstract Sophisticated strategies are required for flood warning in urban areas regarding convective heavy rainfall events. An approach is presented to improve short-term precipitation forecasts by combining ensembles of radar nowcasts with the high-resolution numerical weather predictions COSMO-DE-EPS of the German Weather Service. The combined ensemble forecasts are evaluated and compared to deterministic precipitation forecasts of COSMO-DE. The results show a significantly improved quality of the short-term precipitation forecasts and great potential to improve flood warnings for urban catchments. The combined ensemble forecasts are produced operationally every 5 min. Applications involve the Flood Warning Service Hamburg (WaBiHa) and real-time hydrological simulations with the model KalypsoHydrology.

The rainfall intensity–duration control of shallow landslides and debris flows: an update

Landslides ◽  
2007 ◽  
Vol 5 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Fausto Guzzetti ◽  
Silvia Peruccacci ◽  
Mauro Rossi ◽  
Colin P. Stark
Keyword(s):  
Debris Flows ◽  
Rainfall Intensity ◽  
Shallow Landslides ◽  
Landslides And Debris Flows

scholarly journals Field hydrological monitoring of a sloping shallow pyroclastic deposit

2016 ◽  
Vol 53 (7) ◽  
pp. 1125-1137 ◽  
Author(s):  
Luca Comegna ◽  
Emilia Damiano ◽  
Roberto Greco ◽  
Andrea Guida ◽  
Lucio Olivares ◽  
...  
Keyword(s):  
Debris Flows ◽  
Soil Suction ◽  
Short Term ◽  
Meteorological Forcing ◽  
Rainfall Events ◽  
Triggering Conditions ◽  
Steep Slopes ◽  
Hydrological Monitoring ◽  
Term Response

Many mountainous areas in Campania, southern Italy, are characterized by steep slopes covered by unsaturated volcanic deposits. Shallow landslides are frequently triggered by intense and persistent rainfall events, often turning into debris flows that cause huge damage and casualties. Field hydrological monitoring is a useful tool to develop consistent models of slope response to rainfall, in terms of soil suction and moisture, and to define landslide triggering conditions. This is one of the reasons why since 2002 field monitoring is being carried out in Cervinara, around 50 km northeast of Naples. Since October 2009, rainfall height, soil suction and water content at several locations and depths along the slope are automatically being monitored. The data collected help to demonstrate the effectiveness of such a system for better understanding the hydrological processes occurring in similar slopes of Campania, allowing to distinguish between seasonal suction fluctuations, related to long-term meteorological forcing, and short-term response to rainstorms.

scholarly journals Avaliação da chuva prevista em curto prazo por radar meteorológico

2018 ◽  
Vol 40 ◽  
pp. 42
Author(s):  
Luiz Carlos Salgueiro Donato Bacelar
Keyword(s):  
Cross Correlation ◽  
Rainfall Intensity ◽  
Rain Gauge ◽  
Short Term ◽  
Rainfall Thresholds ◽  
Rain Gauge Data ◽  
Term Forecast ◽  
Surface Rainfall ◽  
Gauge Data ◽  
Accumulated Rainfall

This article presents the first evaluation of the method used by the Brazilian Centre for Monitoring and Early Warning of NaturalDisasters for the short term forecast (nowcasting) of precipitation by weather radar. In this evaluation, four cases of intenserainfall in the radius of Pico do Couto radar were studied, giving the flood risk alerts sent for the municipality of Nova Friburgo,in the state of Rio de Janeiro. In relation to rain gauge data, a median under rate of 43% for the radar precipitation wasobserved when using the SRI (Surface Rainfall Intensity) method. After the rainfall correction, the cross-correlation extrapolationmethod was evaluated for the 30, 60, 90 and 120 minute forecast horizons, with accumulated precipitation every 30 minutes. Theprobabilities of detection (POD) obtained higher values for lower rainfall thresholds (at least 1 or 5 mm of accumulated rainfall)when compared to larger amount accumulated (20 and 30 mm). The spatial and temporal series of rainfall presented higher errors(MAE and RMSE) for 90 and 120 minutes of forecast. For all the events, an overestimate (PBIAS positive) of the predictions wasobserved in relation to the observed radar rain field itself.

scholarly journals Heavy rains in Brno Region (The Czech Republic)

2015 ◽  
Vol 3 (3) ◽  
pp. 12-21
Author(s):  
Gražyna Knozová
Keyword(s):  
Urban Areas ◽  
Rainfall Intensity ◽  
Extreme Rainfall ◽  
Maximum Rainfall ◽  
Extreme Precipitation Events ◽  
Short Period ◽  
Synoptic Conditions ◽  
Average Proportion ◽  
Hydrological System ◽  
Heavy Rains

Abstract This study evaluates occurrence of the heavy rains at urban areas on the example of Brno agglomeration. Extreme precipitation events are studied with the help of 1-minute records from three urban sites in the Brno and one site in the rural region. Additionally data from nine Hellmann rain gauges from Brno and surroundings were used. The event of torrential rains was evaluated according to Wussow’s method. The study found that torrential rains occurred in Brno in the season from April to November. The fifteen-year long observation of the phenomenon at Brno-Žabovřesky station shows varying frequency of torrential rainfall - from none in 2007 to four in 2004 and 2010. The most extremal was catastrophic downpour on July 15, 2009 when precipitation sum reached total up to 42.7 mm in 52 minutes and the maximal rainfall intensity was 4.1 mm/min. This phenomenon occurs only one day after downpour on July 14, 2009. The overall number of torrential episodes is not very high, but it is compensated by the fact that they can repeat in a relatively short period of time, due to specific synoptic conditions. Maximum rainfall intensity during torrential rains reaches values of about 3 mm / min and the average proportion of torrential rain in the daily precipitation sum is around 70%. The phenomenon of heavy rains represents a significant problem for densely populated urban areas because such extreme rainfall has a large impact on the hydrological system of cities.

Sign in / Sign up

Export Citation Format

Share Document