FLOOD ANALYSIS IN THE NUTA RIVER BASIN DURING THE WESTERN JAPAN HEAVY RAIN IN JULY 2018

A devastating flood disaster occurred at Kuala Krai, Kelantan on December 2014. The flood disaster had given a significant destructive impact on the infrastructure and as a result, almost 1,600 homes were lost or destroyed. This extreme flood event killed 25 villages and forced 45,467 people in Kuala Krai, Kelantan to be evacuated from their homes. Continuous heavy rain for over three days from the 21st to the 23rd of December, 2014 was set a rainfall record of 1,295 mm, equivalent to the amount of rain usually seen in a span of 64 days. As a result, the water levels of three major rivers, the Sungai Galas in Dabong, the Sungai Lebir in Tualang and the Sungai Kelantan in Jambatan Gueillemard, rose above the dangerous water levels. It is essential to estimate the extent of flood inundation. The objective of this study is to simulate flood event in December 2014 by using HEC-HMS. The results show the peak discharges and inundations occurred approximately on the 25th December 2014; 18,575.7 m3/s to be almost similar magnitude as reported by DID 2014 Flood Report. These findings led to the conclusion that the HEC-HMS model is useful as a flood analysis tool.

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River discharge prediction for ungauged mountainous river basins during heavy rain events based on seismic noise data

Progress in Earth and Planetary Science ◽

10.1186/s40645-021-00448-1 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Shakti P.C. ◽

Kaoru Sawazaki

Keyword(s):

River Basin ◽

Seismic Noise ◽

River Discharge ◽

Heavy Rain ◽

River Basins ◽

Peak Discharge ◽

Discharge Data ◽

Noise Data ◽

Rain Events ◽

Mountainous River

AbstractSeveral mountainous river basins in Japan do not have a consistent hydrological record due to their complex environment and remoteness, as discharge measurements are not economically feasible. However, understanding the flow rate of rivers during extreme events is essential for preventing flood disasters around river basins. In this study, we used the high-sensitivity seismograph network (Hi-net) of Japan to identify the time and peak discharge of heavy rain events. Hi-net seismograph stations are distributed almost uniformly at distance intervals of approximately 20 km, while being available even in mountainous regions. The Mogami River Basin in Northeastern Japan was selected as a target area to compare the seismic noise data of two Hi-net stations with the hydrological response of a nearby river. These stations are not located near hydrological stations; therefore, direct comparison of seismic noise and observed discharge was not possible. Therefore, discharge data simulated using a hydrological model were first validated with gauging station data for two previous rain events (10–23 July 2004 and 7–16 September 2015). Then, the simulated river discharge was compared with Hi-net seismic noise data for three recent events (10–23 July 2004, 7–16 September 2015, and 10–15 October 2019). The seismic noise data exhibited a similar trend to the time series of simulated discharge in a frequency range of 1–2 Hz for the selected events. Discharge values predicted from the noise data effectively replicate the simulated discharge values in many cases, especially the timing and amount of peak discharge.Simulated and predicted discharge near NIED Hi-net seismic stations in the Mogami River Basin for the event of October 2019 (Typhoon Hagibis).

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RESEARCH REPORT AT THE NENOTANI-GAWA RIVER IN THE OTA-GAWA RIVER BASIN DURING THE HEAVY RAIN EVENT OF JULY 2018

Journal of Japan Society of Civil Engineers Ser B1 (Hydraulic Engineering) ◽

10.2208/jscejhe.75.1_239 ◽

2019 ◽

Vol 75 (1) ◽

pp. 239-243

Author(s):

Mitsutaka NAKANO ◽

Shinya NIGO ◽

Naoyuki IRIKAWA ◽

Yoshiro OMORI

Keyword(s):

River Basin ◽

Heavy Rain ◽

Research Report ◽

Rain Event ◽

Heavy Rain Event

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An Analysis of Factors Influencing Disaster Mobility Using Location Data from Smartphones: Case Study of Western Japan Flooding

Journal of Disaster Research ◽

10.20965/jdr.2019.p0903 ◽

2019 ◽

Vol 14 (6) ◽

pp. 903-911 ◽

Cited By ~ 1

Author(s):

Soohyun Joo ◽

Takehiro Kashiyama ◽

Yoshihide Sekimoto ◽

Toshikazu Seto ◽

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...

Keyword(s):

Cognitive Dissonance ◽

Heavy Rain ◽

Abnormal Behavior ◽

Alert System ◽

Location Data ◽

Significant Damage ◽

Western Japan ◽

Irregular Behavior ◽

Evacuation Behaviors

Western Japan was hit by heavy rain from June 8 to July 28, 2018. Record-breaking rain caused nearly all rivers to flood in Hiroshima and other areas. Over 200 people died following this disaster. Authorities attempted to understand why evacuation was not conducted swiftly enough to stop these deaths. They mentioned that normalcy bias and cognitive dissonance are two primary causes of significant damage [1]. Moreover, an effective alert system is necessary to ensure that evacuation behaviors and procedures are incited at the appropriate time. To understand the factors that influence people’s behavior, we estimated the probability of irregular behavior by unit changes in external condition. We chose 500 m mesh as a unit of analysis to consider individual singularity and classified 3 classes of mesh to identify abnormal behavior. We verified that as the number of residents in each mesh increases, the likelihood of a person in that region to exhibit normalcy bias increases as well. Owing to data, the accuracy of this method is somewhat low. However, several implications may still be drawn from our results, such as the demand for an adequate alert system. Using the results of people’s mobility and disaster risk information, approaches to dangerous situations such as the examined case may be improved in the future.

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