Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Taylor & Francis  

We investigated the merits of performing multi-scale flood simulations with nested two-dimensional flood simulation models for flood risk management applications over an extended period with infiltration and evapotranspiration. For nested calculations, 1) inter-district, 2) district, and 3) regional scales were arranged as three levels in the nested model. Because the nested method can be useful for flat land, the Gaibandha District in Bangladesh was chosen for the study area. This area is a typical flood prone area that is inundated frequently by flood flow from the Jamuna River. First, we performed a year-round flooding simulation for the year 2007 by focusing on a monsoon flood, and validated the results via satellite images. Second, we evaluated the differences of floods in the case of 2.33- and 100-year return periods by using discharge data produced by a flood frequency analysis. We successfully simulated the flooding in each nested level for 2007, and this enabled us to evaluate the flood risks at different scales. In addition, we delineated the flood extent for different return periods and clarified the relationship between the peak water level of the river and the flood extent. The nested method proved to be advantageous because its implementation is not computationally demanding.

File： showCoverImage.pdf

DOI： 10.1080/15715124.2021.1935977

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Language：English   Publishing type：Research paper (scientific journal)  

By utilizing the Green-Ampt infiltration equation and the infinite slope stability model, a method for analyzing shallow slope failures caused by rainfall is developed. With rainfall intensity, soil characteristics, and topography, the modified Green-Ampt infiltration equation is used to estimate the rainfall infiltration capacity and depth of infiltration in a given slope. Assigning the calculated depth of infiltration as the depth of slip surface, the factor of safety of the slope is obtained through the infinite slope stability model. A time-series visualization map of the space-time varying factor of safety is generated when the method is implemented with the aid of Geographic Information System (GIS) software. The model is applied and validated with the landslides that occurred during the October 2019 Typhoon Hagibis in Marumori, Japan. The model results show good agreement with the reported time and depths of failure, and the analysis of the spatial distribution of predicted failures yielded receiver operating characteristic-area under the curve (ROC-AUC) value of 0.90. The applicability of the model can be extended for post-analysis, real-time, or projected assessment of slope stability, depending on the nature of input rainfall data (e.g., historical, real-time, forecast, hypothetical).

File： 10346.pdf

DOI： 10.1007/s10346-020-01617-x

Scopus

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ScienceDirect  

Typhoon Hagibis struck Japan on October 12–13, 2019. There was substantial damage over a wide area including the Tohoku region. In particular, Marumori Town, an urban area in Miyagi Prefecture that includes a town hall, was flooded due to heavy rain. The maximum cumulative rainfall and hourly rainfall measured in the town were over 600 and 70 mm, respectively. Heavy rain caused river flooding and landslides throughout the town, resulting in 10 deaths and one missing person. There was also substantial damage to the infrastructure, such as roads, railways, and river levees. The authors performed a field survey immediately after the disaster, and analyzed the observed data. Most levee breaches occurred due to overflow. A breached levee that failed in an unusual direction, namely, a failure which took place from the landside toward the waterside, was also observed. Landslides were not only caused by the amount of rainfall, but also by geological and topographical factors. Roads and railways were damaged by both river flooding and landslides. While both river flooding and landslides occurred in the Usudaira community, which is in the middle reaches of the Gofukuya River, there were no deaths or missing persons. This should be an important case for future disaster mitigation.

File： Unknown2.pdf

DOI： 10.1016/j.sandf.2021.01.009

Scopus

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

Previous applications of machine learning in remote sensing for the identification of damaged buildings in the aftermath of a large-scale disaster have been successful. However, standard methods do not consider the complexity and costs of compiling a training data set after a large-scale disaster. In this article, we study disaster events in which the intensity can be modeled via numerical simulation and/or instrumentation. For such cases, two fully automatic procedures for the detection of severely damaged buildings are introduced. The fundamental assumption is that samples that are located in areas with low disaster intensity mainly represent nondamaged buildings. Furthermore, areas with moderate to strong disaster intensities likely contain damaged and nondamaged buildings. Under this assumption, a procedure that is based on the automatic selection of training samples for learning and calibrating the standard support vector machine classifier is utilized. The second procedure is based on the use of two regularization parameters to define the support vectors. These frameworks avoid the collection of labeled building samples via field surveys and/or visual inspection of optical images, which requires a significant amount of time. The performance of the proposed method is evaluated via application to three real cases: the 2011 Tohoku-Oki earthquake-tsunami, the 2016 Kumamoto earthquake, and the 2018 Okayama floods. The resulted accuracy ranges between 0.85 and 0.89, and thus, it shows that the result can be used for the rapid allocation of affected buildings.

File： IEEE-Transactions-on-Geoscience-and-Remote-Sensing.pdf

DOI： 10.1109/tgrs.2020.3046004

Scopus

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Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10346-021-01642-4

Scopus

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

File： jscejhe_77_1.pdf

DOI： 10.2208/jscejhe.75.2_I_1279

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

File： jscejhe_77_1.pdf

DOI： 10.2208/jscejhe.74.5_I_967

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Fuji Technology Press Ltd.  

This study investigated the vertical accuracy of satellite elevation data and its effect on flood and substance transportation analysis by using a two-dimensional flood simulation model. SRTM, AW3D, and ASTER GDEM satellite elevation data for East Dhaka, Bangladesh were used for evaluating the vertical accuracy and conducting numerical analyses. A case study in 2007 was simulated for the flooding analysis. The results showed that AW3D had the highest applicability because its vertical accuracy for low-lying areas was better than that of the other products. According to the differences in the flood extent of each satellite elevation data, the simulation results of the substance transportation analysis showed different spreading conditions. Furthermore, differences in the flood velocity and direction affected the distribution of the deposited substance.

File： Unknown.pdf

DOI： 10.20965/jdr.2018.p0967

Scopus

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JSNDS  

Riverbank erosion is a vital issue in the management and restoration of rivers, especially in alluvial meandering channels because of their unique channel morpho-dynamics. Various countermeasures are thus implemented to minimize riverbank erosion and maintain stable channel sections of meandering channels. This study analyzes the performance of modified impermeable groynes with sloped crests as a countermeasure for bank erosion. Experiments were conducted in erodible meandering channels of two different sinuosities to evaluate the performance of the proposed countermeasures under varying sinuosity as well as analyze the overall morphological evolution of the channel. The results show that the low sinuosity (LS) channel was more prone to erosion compared to the higher sinuosity (HS) channel. Channel sinuosity also affected the overall channel morphological evolution with the LS channel showing more distinct characteristics of a meandering channel forming point bar and pool and riffle sequences. The proposed countermeasure showed slightly better performance in the case of the LS channel. Although the presence of the proposed groynes did not significantly deflect the high-velocity core towards the channel center, the velocity near the bank region was significantly reduced.

File： 20220105_IOURNALOFIARAINSOCIETY.pdf

DOI： 10.24762/jndsj.37.S05_93

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

The experimental study presented herein discusses the short-term evolution of flow and morphology in an erodible meandering channel under steady discharge, with and without groyne structures. Experiments were conducted in a low sinuosity meandering channel with erodible bed and erodible banks composed of non-cohesive, non-uniform sediment. Series of groynes were placed as a countermeasure with an objective to study its effect on the erosion control, planform shifting and overall channel morphology. Various parameters of flow and morphology viz. channel topography, surface velocity distribution and water level were measured in order to analyze and compare differences in channel evolution, velocity distribution and water surface profile variation in the presence of groynes structures. Results showed a significant change in channel morphology and flow field with groynes like reduction in the size of point bar, deflection of high-velocity zone towards the channel center and an overall rise in the water surface profile. Although the presence of groynes resulted in the overall reduction in erosion by deflecting the flow towards the center, the outer bank region (especially between the groynes) still remained at the risk of erosion.

File： jscejhe_77_1.pdf

DOI： 10.2208/jscejhe.74.I_1147

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

In this study, we focused on the effect of the riverbed aggradation to thescale of the flood inundation. Using the distributed runoff model, one dimensional riverbed variation calculation and 2 dimensional flood inundation mode, we performed a flooding analysis for a flash flood in an ungauged basin. Due to the limitation of the available dataset, firstly we performed a riverbed variation calculation using observed daily discharge and water level that were observed during April-Sept 2000. Secondly, we performed a runoff analysis using 3 hourly satellite rainfall data that was observed during April-May 2006. Finally, riverbed data and discharge data was considered to the flash flood inundation analysis. As a result, after the riverbed aggradation was considered, the flood area become2 times larger that the case riverbed aggradation was not considered.

File： jscejhe_77_1.pdf

DOI： 10.2208/jscejhe.73.I_1393

CiNii Books

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

We attempted numerical simulation of the Kinu River flood inundation in the Joso City in 2015. In the inundated areas, sedimentation on the paddy fields and water drainage gutters was serious problem. In our simulation, we tried to reproduce flood inundation flow and its attendant sedimentation in the study area. In order to consider the ridges and irrigation channels of the paddy fields, the models of vertical walls and one-dimensional network of channels are incorporated in the two-dimensional inundation flow model. The maximum water level simulated here agreed well with the measured one, and approximately 50 cm sedi- mentation was observed on the overland and irrigation channels around the overflow and dyke breach points, which might have caused a severe damage to rice crops in the paddy fields and disorder of drainage function of irrigation channel after the inundation.

File： jscejhe_77_1.pdf

DOI： 10.2208/jscejhe.73.I_1435

CiNii Books

J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

The presence of polders in southwestern Bangladesh leading to gradual silting up of rivers which, in turn, has resulted in serious waterlogging rendering large tract of land uncultivable. The current practice to solve this issue is temporarily de-poldering by cutting embankment. It allows natural movement of sediment-borne tidal water into a selected beel known as tidal basin and allows deposition of sediment. Sedimentation de- termines the life span of basin and the rate of raising the land. It is essential that better understanding of sedimentation process is required. One significant hydraulic fact is that the faster the flow is, the more sediment it can carry with it. One of the key governing factor of the flow is opening size of link canal. In this research, attempts have been made to inspect the effectiveness of tidal basin management investigating different opening sizes of link canal through laboratory experiments and preliminary numerical simulation. Our finding shows sediment carrying capacity is a function of velocity. Moreover, only increasing the opening size of link canal will not allow more sediment to deposit in selected tidal basin. It is also found in experiment that near the embankment, where tidal flow enters during high tide and leaves during low tide, vortex like formation tries to erode the material which in real case also happens. Developed numerical model has good agreement with experimental results and can be used to better understand effectiveness of tidal basin management.

File： jscejhe_77_1.pdf

DOI： 10.2208/jscejhe.73.I_781

CiNii Books

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

We examined the methods of the nested flood simulation model using unstructured grids. Water depth and discharge were used for connection of nesting calculation, and these results were compared with the reference calculation that did not employ the nested calculation. In order to compare the result with the previous studies, we performed flooding calculation with structure-unstructured grids nesting and unstructured-unstructured grids nesting, and they were applied to an uneven terrain of the Jamuna River basin in Bangladesh. As a result, nested calculation using water depth showed good agreement with the reference calculation, and result with discharge showed over estimation. For the further research, applicability of these methods should be confirmed in the cases where high flow velocity is observed.

File： jscejhe_77_1.pdf

DOI： 10.2208/jscejhe.72.I_319

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

We examined the methods of the nested flood simulation model focusing on the situation where dry beds are frequently present. New nested methods were developed to solve the error that caused by dry bed. The methods were applied to an uneven terrain of Bangladesh, and the methods have been validated by performing flooding simulations on the area. Method to pass the discharge and to pass the water level were applied to the trial simulation, and its results were compared with the result of the un-nested model with fine grids. Consequently, the results of the nested method using water level were superior on the viewpoint of flooded area, depth and volume. For the further research, consideration of the roughness depending on the grid size was suggested.

File： jscejhe_77_1.pdf

DOI： 10.2208/jscejhe.71.I_1459

CiNii Books

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

We quantitatively investigated the relationship between flood conditions and the incidence of diarrhoea caused by flooding in Dhaka City, Bangladesh, by using a two-dimensional flood simulation model. We performed flooding simulation in target areas, and the simulated results were compared to diarrhoeal morbidity. Diarrhoea causes were assessed through home-visit morbidity surveys; these surveys were conducted three times in different phases of the rainy season (pre, mid and post-monsoon) in 10 low-income communities in flood-prone areas of Dhaka City, targeting children below five years of age. The results revealed that flooding influences the morbidity of diarrhoea, as increased morbidity was identified in almost all communities in the mid-monsoon season. However, cases with a predisposition of diarrhoea such as socioeconomic status were also identified, as morbidity was observed in pre- and post-monsoon seasons when flooding did not occur. Furthermore, morbidity was higher in areas with maximum flooding depth of 0.7?1.2 m than that in areas with maximum flooding depth of 0.1?0.2 m in each season. Consequently, we found that the gradient of diarrhoeal vulnerability is affected by predisposing factors such as socioeconomic status, and its influence is maintained throughout the rainy season.

File： unnamed.pdf

DOI： 10.3178/hrl.8.96

J-GLOBAL

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

An increase in waterborne illnesses related to floodings has been reported all over the world, especially in developing countries. In Dhaka City, floodings occur almost every year due to severe rainfall without adequate drainage. Waterborne illnesses spread easily in an unhygienic environment. This study developed a method to estimate the incidences of diarrhoea associated with floodings using a flooding analysis. We performed a flooding analysis using a numerical flooding simulation model and investigated the relationship between floodwater depth and diarrhoea incidence. The incidence of diarrhoea was assessed through a mortality and morbidity survey conducted in 10 low-income communities in flood-prone areas of Dhaka City. The results showed a positive correlation between floodwater depth and diarrhoea incidence. This indicates that a flooding analysis method can be used to estimate diarrhoea incidence.

File： 41ywoqXFWLL.pdf

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Language：Japanese   Publishing type：Research paper (scientific journal)  

in Japanese

File： images.pdf

DOI： 10.20820/suirikagaku.57.2_36

CiNii Books

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Bangladesh is one of the most flood-prone countries in the world. Especially, in Dhaka city, capital of Bangladesh, inundation problem is very serious. To prevent the social problem caused by inundation, such as traffic jam and health risk in low lying slum areas, it is important to evaluate the influence of inundations for plan to develop the city. In such a developing country, dataset about hydrology is not enough to perform inundation analysis. Therefore sensitivity analysis was performed for 1) DEM, 2) embankment, 3) building occupied ratio and 4) rivers as beginning step to evaluate the inundation condition. From the result, it was found that inundation in city areas is not only caused by elevation deference. Especially the influence of building ratio is remarkable as a cause of inundation, secondary, embankment is effective. As a further extent, sewerage network should be considered to simulate the inundation with more high accuracy at overestimated area in this study.

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Forest Conservation Association  

File： images.pdf

DOI： 10.20820/suirikagaku.55.5_104

CiNii Books

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Authorship：Corresponding author   Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)   Publisher：the 39th IAHR World Congress  

River management in urban areas is of fundamental importance for the safety control of these environments. Mainly located in the floodplain areas, the riparian vegetation plays an important role on the conveyance capacity of rivers, as it is directly related to hydraulic roughness. One way to reduce flood risk, is to decrease the floodplain roughness by controlling the vegetation population. The wide variation of characteristics, such as height, foliage density and branch configuration, are important factors in defining roughness, making the identification of the many vegetation species in river environments an important task for studying the river’s hydrological processes. Obtaining these characteristics by traditional surveying methods is time consuming and financially expensive. Recent techniques combining the use of Unmanned Aerial Vehicles (UAV) and optical cameras have been implemented as a more time- and cost-effective way to survey riverine areas. UAV photogrammetry derived 3D point clouds are powerful datasets for digital recreation of 3 dimensional terrains, with practical uses for river management, e.g., for feature classification of river environments. Moreover, techniques such as Machine Learning (ML) have become popular for image classification. Different algorithms have been developed and applied for that objective, achieving overall good accuracy. The objective of this study is to combine the use of classification ML techniques to classify the vegetation species in a 2 km stretch of the Nanakita river, in Miyagi prefecture of Japan, from the 3D point cloud data available for the area, and to use the species information in a 2D hydraulic model adapted to interpret the vegetation information and dynamically estimate the hydraulic roughness using the real case of typhoon Hagibis of 2019. The point classification was performed in two parts. First, to differentiate the vegetated points from ground points and other objects, color-based region growing semantic segmentation was used. With the vegetation points completely filtered, a sample number of points were labeled into different species and set as training area for the ML algorithm Random Forest (RF), which, once trained, was used to classify the species in the entire UAV observed area. Once the classification was completed, the information regarding the vegetation was divided into the terrain grid cells and prepared for the 2D hydraulic model. The accuracy of the model was observed by comparing the results with a different simulation not considering the vegetation effect. The species differentiation highlighted the different plant characteristics that could influence the hydraulic roughness. The scenario simulated in the adapted 2D hydraulic model considering the vegetation characteristics obtained more accurate results when compared with the simulation with observed roughness values, without the estimated roughness from the vegetation.

DOI： 10.3850/IAHR-39WC2521711920221003

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Other Link： https://www.iahr.org/library/infor?pid=21325

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)   Publisher：the 39th IAHR World Congress  

We examined the characteristics of spatial distribution of riparian population and buildings along with the medium and small sized rivers in Tohoku Region, Japan. Recently, the number of cases that have damage near the medium and small sized river is increasing in Japan. Furthermore, the victims tend to be elder people who failed to evacuate in the early stage. To reduce the risk of that areas, appropriate observation and inspection need to be done with high-efficient and low-cost method such as UAV-SfM observations. For the high-efficient observations, levels of preference are better to be set with the information of riparian population and buildings. Thus, the objective of this study is to reveal the spatial distribution of riparian population and buildings quantitatively at medium and small sized river in Tohoku Region, Japan. We used data for the spatial distribution of population with the information of number of people aged 65 years old and 75 years old, and location of rivers as well. In this study we defined that riparian population is in the range of 250m which could cover the area damaged by the passed sever flood disasters near medium and small rivers. As a result, we revealed that the average residential ratio of medium and small sized river is about 60 % in Tohoku Region and the ratio was lower than the other area such as Kanto Region and Kyushu Region. For the further analysis, we plan to reveal the spatial distribution of the people older than 65 years old and the vulnerable area with elder people will to be identified.

DOI： 10.3850/IAHR-39WC2521716X20221843

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Other Link： https://www.iahr.org/library/infor?pid=20814

Authorship：Lead author   Language：Japanese   Publishing type：Book review, literature introduction, etc.   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

田中隆文 著，古今書院，2021年，240ページ，
本体 3,600円（税別），ISBN: 978-4-772-24223-3

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Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.3178/jjshwr.33.274

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Language：Japanese  

CiNii Books

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Language：Japanese   Publishing type：Meeting report   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.3178/jjshwr.33.17

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Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)   Publisher：IAHR (International Association for Hydro-Environment Engineering and Research)  

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Language：English   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)   Publisher：Disaster Prevention Research Institute, Kyoto University  

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Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

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Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)   Publisher：IAHR (International Association for Hydro-Environment Engineering and Research)  

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Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)   Publisher：IAHR (International Association for Hydro-Environment Engineering and Research)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

J-GLOBAL

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Language：English   Publishing type：Research paper, summary (national, other academic conference)  

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)   Publisher：IAHR (International Association for Hydro-Environment Engineering and Research)  

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper, summary (national, other academic conference)  

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper, summary (national, other academic conference)   Publisher：IAHR (International Association for Hydro-Environment Engineering and Research)  

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper, summary (national, other academic conference)  

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)   Publisher：Disaster Prevention Research Institute, Kyoto University  

CiNii Books

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Other Link： http://id.ndl.go.jp/bib/027653300

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper, summary (national, other academic conference)  

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)   Publisher：Disaster Prevention Research Institute, Kyoto University  

CiNii Books

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

Younger generation party was established to create strong human network including other study field. This active report is to report its activity in 2012. On September in 2012, discussion camp was held in Hiroshima. In the camp, 16 members form 9 universities participated. Discussion theme was not about study, but about how to live or what we want to be.  Since discussion camp was not about studying, study meeting was held twice. First one is for mutual-understanding among the party. Second one is to design projects with the party members.  To interplay with other study field, some members participated symposiums. We participated "Younger Generation Party to Think about Forest Hydrology" and make presentation about our future collaboration.  And we are making homepage to show our activity. And we made some party and "Hydrocup", and made tour to Kitami city in Hokkaido.

DOI： 10.11520/jshwr.26.0.72.0

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

CiNii Books

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Event date： 2022.9

Language：English   Presentation type：Oral presentation (general)  

Venue：オーストラリア, シドニー   Country：Australia  

Flood disasters have caused multiple victims across countries. In various cases, casualties are due to late evacuation or a lack of timely advisory. Thus, we optimize the advisory time and the evacuation process when heavy rains or typhoons threaten to flood cities. We find the worst case of population exposure and evacuation advisory using reinforcement learning and stochastic programming. We combine mobile statistical data, flooding scenarios, and evacuation behavior. Finally, we discuss the advantages and disadvantages of stochastic programming and reinforcement learning to sketch up the problem in a sequential decision analysis framework, bridging Operational Research and Machine Learning fields.

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Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Ritsumeikan University Biwako Kusatsu Campus   Country：Japan  

Chair: Dr. Susumu Nakano (Tokushima University)

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Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Ritsumeikan University Biwako Kusatsu Campus   Country：Japan  

Session: Improving Disaster Preparedness, 14:20-15:50, Chair: Prof. Kanai (Tokushima University), Prof. Takenouchi (Kagawa University)

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Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Country：Japan  

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Event date： 2022.7 - 2022.8

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2022.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Granada, Spain  

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Event date： 2022.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Palacio de Congresos de Granada, Granada, Spain   Country：Spain  

River management is an important activity for both ecological protection and the safety of nearby populations. The acquisition of information on vegetation conditions for river management is a difficult task and is often neglected, although recently, it has been facilitated by unmanned aerial vehicle (UAV) technology. This technological advancement, along with artificial intelligence algorithms, has enabled river management professionals and researchers to identify vegetation in riverine areas. Moreover, the use of UAV photogrammetry allows the observation of characteristics, such as vegetation height. This study aims to identify the vegetation patterns and height variation over the course of one year in a 2 km stretch of the Nanakita River in Miyagi, Japan, using monthly UAV-derived 3D point cloud data and artificial neural networks. The vegetation was successfully located for each of the observed months, achieving an accuracy of 98% for spring and summer and 96% for autumn and winter. The area and average height were calculated for each month, and the results showed a pattern of variation of the vegetation amount, demonstrating that summer has a peak amount, as opposed to the winter period. The applied method was effective for the objectives, proving that UAV imagery is an important tool for river management.

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Event date： 2022.6

Language：English   Presentation type：Poster presentation  

Venue：Granada, Spain   Country：Spain  

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Event date： 2022.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Sendai City   Country：Japan  

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Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：On-line   Country：Japan  

File： matome_handout.pdf

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Event date： 2021.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：On-line (Organized by Tokushima local office)   Country：Japan  

Chair: Dr. Satofuka（Ritsumeikan University）, Dr. Yamanoi（Kyoto University）

File： matome_handout.pdf

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Event date： 2021.7

Language：English   Presentation type：Oral presentation (general)  

Country：Korea, Republic of  

Most of the rivers in Japan, in terms of river length, are small to medium-sized rivers managed by prefectural governments. Due to financial and human resource constraints, prefectural governments are not able to conduct river channel maintenance and management, such as weeding of embankments, river channel inspection, and cross-sectional surveying, which should be conducted on a regular basis. Under the climatic changes, many small and medium-sized rivers have suffered from flood damage. The implementation of river channel maintenance is also important to reduce flood risks. On the other hand, in Japan, there has been a system of river protection activities in which local residents weed and clean the embankments since a long time ago. In addition, some communities have a system to report to the government when residents find abnormalities such as deformations or sediment accumulation on the banks during protection activities or on a daily basis. However, in some cases, the information is not fully utilized for river maintenance and management due to inadequate reporting forms and manuals, lack of expertise, and other factors. We believe that the information provided by residents, is important for assessing flow capacity, inspecting facilities, and monitoring the river channel. In this study, we examined what kind of technology is easy for residents and river administrators to handle, and investigated the optimum UAV photogrammetry operation by using the river information from local residents. As a result, we proposed an accurate and cost-effective observation method with the river information.
pp.206-207.

File： 市川掲載分_20210720_9th ISEH Proceedings-2.pdf

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Event date： 2021.7

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2021.6

Language：Japanese   Presentation type：Poster presentation  

Country：Japan  

In our previous study, we confirmed that UAV photogrammetry taken at an altitude of 50m can accurately determine the height of embankments. We also confirmed that the required accuracy varies depending on the river administrator through interviews with small river administrators.
In this study, to develop an optimal UAV photogrammetry method focusing on the accuracy of levee height measurement, measurements were carried out by changing the altitude of UAV photography and the point cloud density of SfM analysis. As a result, it was found that when the required accuracy of levee height measurement was less than 5 cm, the altitude was less than 70 m. On the other hand, when the required accuracy was less than 10 cm, the altitude was 90 m.

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Event date： 2021.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Online, Dhaka City, Bangladesh   Country：Bangladesh  

Online, 2021/3/30 15:00-15:15 (session 14:15-15:45 JPT, 11:15-12:45BDT). Chair person: Sonia Binte Murshed

File： matome_handout.pdf

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Event date： 2021.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：On-line (Organized by Kumamoto local office)   Country：Japan  

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Event date： 2021.3

Language：English   Presentation type：Oral presentation (general)  

Venue：On-line   Country：Japan  

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Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：On-line   Country：Japan  

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Event date： 2020.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Tagata campus, Akita University   Country：Japan  

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Event date： 2019.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Yamagata   Country：Japan  

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Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

File： jscejhe_77_1.pdf

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Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kushiro Lifelong Learning Center   Country：Japan  

File： jsnds2019発表資料2.pdf

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Event date： 2019.9

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2019.6

Presentation type：Symposium, workshop panel (public)  

Venue：UC Davis, CA USA   Country：United States  

File： APRU_workshop_handout.pdf

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Event date： 2018.11

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

File： jscejhe_77_1.pdf

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Event date： 2018.10

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Riverbank erosion is a vital issue in the management and restoration of rivers, especially in alluvial meandering channels because of their unique channel morpho-dynamics. Various countermeasures are thus implemented to minimize riverbank erosion and maintain stable channel sections of meandering channels. This study analyzes the performance of modified impermeable groynes with sloped crests as a countermeasure for bank erosion. Experiments were conducted in erodible meandering channels of two different sinuosities to evaluate the performance of the proposed countermeasures under varying sinuosity as well as analyze the overall morphological evolution of the channel. The results show that the low sinuosity (LS) channel was more prone to erosion compared to the higher sinuosity (HS) channel. Channel sinuosity also affected the overall channel morphological evolution with the LS channel showing more distinct characteristics of a meandering channel forming point bar and pool and riffle sequences. The proposed countermeasure showed slightly better performance in the case of the LS channel. Although the presence of the proposed groynes did not significantly deflect the high-velocity core towards the channel center, the velocity near the bank region was significantly reduced.

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Event date： 2018.8

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2018.8

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2018.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岩手大学理工学部総合教育研究棟（環境系）   Country：Japan  

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Event date： 2018.3

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

The experimental study presented herein discusses the short-term evolution of flow and morphology in an erodible meandering channel under steady discharge, with and without groyne structures. Experiments were conducted in a low sinuosity meandering channel with erodible bed and erodible banks composed of non-cohesive, non-uniform sediment. Series of groynes were placed as a countermeasure with an objective to study its effect on the erosion control, planform shifting and overall channel morphology. Various parameters of flow and morphology viz. channel topography, surface velocity distribution and water level were measured in order to analyze and compare differences in channel evolution, velocity distribution and water surface profile variation in the presence of groynes structures. Results showed a significant change in channel morphology and flow field with groynes like reduction in the size of point bar, deflection of high-velocity zone towards the channel center and an overall rise in the water surface profile. Although the presence of groynes resulted in the overall reduction in erosion by deflecting the flow towards the center, the outer bank region (especially between the groynes) still remained at the risk of erosion.

File： jscejhe_77_1.pdf

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Event date： 2017.11

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2017.8

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2017.3

Language：English  

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Event date： 2017.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

In this study, we focused on the effect of the riverbed aggradation to thescale of the flood inundation. Using the distributed runoff model, one dimensional riverbed variation calculation and 2 dimensional flood inundation mode, we performed a flooding analysis for a flash flood in an ungauged basin. Due to the limitation of the available dataset, firstly we performed a riverbed variation calculation using observed daily discharge and water level that were observed during April-Sept 2000. Secondly, we performed a runoff analysis using 3 hourly satellite rainfall data that was observed during April-May 2006. Finally, riverbed data and discharge data was considered to the flash flood inundation analysis. As a result, after the riverbed aggradation was considered, the flood area become2 times larger that the case riverbed aggradation was not considered.

File： jscejhe_77_1.pdf

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Event date： 2017.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

We attempted numerical simulation of the Kinu River flood inundation in the Joso City in 2015. In the inundated areas, sedimentation on the paddy fields and water drainage gutters was serious problem. In our simulation, we tried to reproduce flood inundation flow and its attendant sedimentation in the study area. In order to consider the ridges and irrigation channels of the paddy fields, the models of vertical walls and one-dimensional network of channels are incorporated in the two-dimensional inundation flow model. The maximum water level simulated here agreed well with the measured one, and approximately 50 cm sedi- mentation was observed on the overland and irrigation channels around the overflow and dyke breach points, which might have caused a severe damage to rice crops in the paddy fields and disorder of drainage function of irrigation channel after the inundation.

File： jscejhe_77_1.pdf

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Event date： 2017.3

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

The presence of polders in southwestern Bangladesh leading to gradual silting up of rivers which, in turn, has resulted in serious waterlogging rendering large tract of land uncultivable. The current practice to solve this issue is temporarily de-poldering by cutting embankment. It allows natural movement of sediment-borne tidal water into a selected beel known as tidal basin and allows deposition of sediment. Sedimentation de- termines the life span of basin and the rate of raising the land. It is essential that better understanding of sedimentation process is required. One significant hydraulic fact is that the faster the flow is, the more sediment it can carry with it. One of the key governing factor of the flow is opening size of link canal. In this research, attempts have been made to inspect the effectiveness of tidal basin management investigating different opening sizes of link canal through laboratory experiments and preliminary numerical simulation. Our finding shows sediment carrying capacity is a function of velocity. Moreover, only increasing the opening size of link canal will not allow more sediment to deposit in selected tidal basin. It is also found in experiment that near the embankment, where tidal flow enters during high tide and leaves during low tide, vortex like formation tries to erode the material which in real case also happens. Developed numerical model has good agreement with experimental results and can be used to better understand effectiveness of tidal basin management.

File： jscejhe_77_1.pdf

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Event date： 2016.11

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2016.8

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

We examined the methods of the nested flood simulation model using unstructured grids. Water depth and discharge were used for connection of nesting calculation, and these results were compared with the reference calculation that did not employ the nested calculation. In order to compare the result with the previous studies, we performed flooding calculation with structure-unstructured grids nesting and unstructured-unstructured grids nesting, and they were applied to an uneven terrain of the Jamuna River basin in Bangladesh. As a result, nested calculation using water depth showed good agreement with the reference calculation, and result with discharge showed over estimation. For the further research, applicability of these methods should be confirmed in the cases where high flow velocity is observed.

File： jscejhe_77_1.pdf

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Event date： 2016.2

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Yamaguchi   Country：Japan  

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Event date： 2015.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

We examined the methods of the nested flood simulation model focusing on the situation where dry beds are frequently present. New nested methods were developed to solve the error that caused by dry bed. The methods were applied to an uneven terrain of Bangladesh, and the methods have been validated by performing flooding simulations on the area. Method to pass the discharge and to pass the water level were applied to the trial simulation, and its results were compared with the result of the un-nested model with fine grids. Consequently, the results of the nested method using water level were superior on the viewpoint of flooded area, depth and volume. For the further research, consideration of the roughness depending on the grid size was suggested.

File： jscejhe_77_1.pdf

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Event date： 2015.3

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2012

Language：Japanese   Presentation type：Poster presentation  

Country：Japan  

Bangladesh is one of the most flood-prone countries in the world. Especially, in Dhaka city, capital of Bangladesh, inundation problem is very serious. To prevent the social problem caused by inundation, such as traffic jam and health risk in low lying slum areas, it is important to evaluate the influence of inundations for plan to develop the city. In such a developing country, dataset about hydrology is not enough to perform inundation analysis. Therefore sensitivity analysis was performed for 1) DEM, 2) embankment, 3) building occupied ratio and 4) rivers as beginning step to evaluate the inundation condition. From the result, it was found that inundation in city areas is not only caused by elevation deference. Especially the influence of building ratio is remarkable as a cause of inundation, secondary, embankment is effective. As a further extent, sewerage network should be considered to simulate the inundation with more high accuracy at overestimated area in this study.

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

Venue：Sendai, Japan   Country：Japan  

File： 191111_p.pdf

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Language：English   Presentation type：Poster presentation  

Venue：Sendai, Japan   Country：Japan  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Bangladesh   Country：Bangladesh  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Bangladesh   Country：Bangladesh  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Bangladesh   Country：Bangladesh  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Nigata   Country：Japan  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Shizuoka   Country：Japan  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Japan   Country：Japan  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto, Japan   Country：Japan  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kagoshima   Country：Japan  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kobe   Country：Japan  

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Language：English   Presentation type：Poster presentation  

Venue：San Francisco   Country：United States  

An increase in waterborne illnesses related to floodings has been reported all over the world, especially in developing countries. In Dhaka City, floodings occur almost every year due to severe rainfall compounded by inadequate sewerage systems. Waterborne illnesses spread easily in an unhygienic environment. This study develops a method to estimate the incidences of diarrhoea associated with floodings using a flooding analysis. We performed a flooding analysis using a numerical flooding simulation model and investigated the relationship between floodwater depth and diarrhoea incidence. The incidence of diarrhoea was assessed through a mortality and morbidity survey conducted in 10 low-income communities in flood-prone areas of Dhaka City. The results revealed that there is a positive correlation between floodwater depth and indices of diarrhoea incidence. This indicates that a flooding analysis method can be used to estimate diarrhoea incidence.

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Language：English   Presentation type：Oral presentation (general)  

Venue：Viet Nam  

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Language：Japanese   Presentation type：Poster presentation  

Venue：Hiroshima   Country：Japan  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Hiroshima   Country：Japan  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Nagoya   Country：Japan  

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Language：English   Presentation type：Poster presentation  

Venue：San Francisco   Country：United States  

Although some studies have been carried out on the spread of infectious disease with the flooding, the relation between flooding and the infectious expansion has not been clarified yet. The improvement of the calculation precision of inundation and its relation with the infectious disease, surveyed epidemiologically, are therefore investigated in a case study in Dhaka city, Bangladesh. The inundation was computed using a flood simulation model that is numerical 2D-model. The "sensitivity to inundation" of hydraulic factors such as drainage channel, dike, and the building occupied ratio was examined because of the lack of digital data set related to flood simulation. Each element in the flood simulation model was incorporated progressively and results were compared with the calculation result as inspection materials by the inundation classification from the existing study (Mollah et al., 2007). The results show that the influences by ''dyke'' and "drainage channel" factors are remarkable to water level near each facility. The inundation level and duration have influence on wide areas when "building occupied ratio" is also considered. The correlation between maximum inundation depth and health risk (DALY, Mortality, Morbidity) was found, but the validation of the inundation model for this case has not been performed yet. The flood simulation model needs to be validated by observed inundation depth. The drainage facilities such as sewer network or the pumping system will be also considered in the further research to improve the precision of the inundation model.

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Language：English   Presentation type：Oral presentation (general)  

Venue：Hokkaido   Country：Japan  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

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Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

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Award type：Award from Japanese society, conference, symposium, etc.  Country：Bangladesh

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Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

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Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

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Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

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Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

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Audience： Governmental agency

Type：Seminar, workshop

File： matome_handout.pdf

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Audience： Teachers

Type：Lecture

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Audience： General

Type：Investigation, survey

File： f74d4865ca9a0b176e1857d97fb70c2c.pdf

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Audience： General

Type：Lecture

File： 知水講座_本番handout3.pdf

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Audience： General

Type：Seminar, workshop

File： matome_handout.pdf

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Audience： General,　Governmental agency

Type：Lecture

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Audience： Media

Type：Other

File： tohokuuniv-press20200526_02web_river.pdf

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Audience： General

Type：Lecture

File： seminar.pdf

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Type：Citizen’s meeting/Assembly

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Audience： General

Type：Seminar, workshop

令和元年台風第19号によって東日本各地で甚大な被害がありました。本講演では、一連の降雨イベントを改めて振り返り、水害・土砂災害等の被害の概要を紹介した後、鳴瀬川水系吉田川の粕川破堤点付近の現地調査について紹介します。

File： 震災技術展_handout3.pdf

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Audience： Teachers

Type：Lecture

File： 20191101_ho.pdf

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Audience： General

Type：Seminar, workshop

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Audience： General

Type：Lecture

File： matome_handout.pdf

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Audience： General

Type：Lecture

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Author：Other 

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Type：Academic society, research group, etc. 

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zoom開催の補助を行った．

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Type：Academic society, research group, etc. 

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Type：Academic research 

助成番号:2019‐5112‐002
機関名:土木学会令和元年台風 19 号豪雨災害調査団 総団長 清水 義彦
東北地区団長 田中 仁
https://committees.jsce.or.jp/report/system/files/tohoku.pdf

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Type：Peer review 

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