{"title":"Development of Flash Flood Forecasting System for Small and Medium-Sized Rivers","authors":"Koji Ikeuchi, Daiki Kakinuma, Yosuke Nakamura, Shingo Numata, Takafumi Mochizuki, Keijiro Kubota, Masaki Yasukawa, Toshihiro Nemoto, Toshio Koike","doi":"10.1111/jfr3.70026","DOIUrl":null,"url":null,"abstract":"<p>Owing to the increased frequency of short-duration extreme rainfall events caused by climate change, peak flood flows are expected to increase substantially in small and medium-sized rivers (SMRs) with a short time of concentration for a catchment (Tc). Accurate flood forecasts and corresponding evacuation are effective in reducing the number of casualties caused by flash floods in SMRs. Currently, flood forecasting using observed rainfall in SMRs has a short lead time, which often delays the issuance of evacuation orders by local governments. Moreover, the large number of SMRs necessitates a system that can be widely used by local governments for disaster response tasks, such as issuing evacuation orders. Therefore, we developed a system that can accurately predict when river water levels will reach the Flood Risk Level (FRL). This forecasting approach uses the rainfall–runoff–inundation (RRI) model and the H–Q equation. The parameters in the RRI model were optimized using the Shuffled Complex Evolution algorithm developed at the University of Arizona (SCE-UA) to reduce the required time and effort. The system uses real-time water level observation data to sequentially modify the basin state quantities in the RRI model using the particle filter method to improve the water level forecast accuracy. The system was implemented in 200 rivers in Japan with diverse rainfall and geological characteristics and was tested during the flood season. Accuracy verification was conducted when the forecasted water levels were operated within a range of ± 50 cm. The results showed that 75% of the flood events could be forecasted more than 2 h before reaching the FRLs. Furthermore, 89% of the flood events could be predicted with a lead time (LT; time that water levels reach the FRL—time of first forecast) of 2 h or more or a lead time equal to the Tc or more. These findings show that this system has the potential to enhance and strengthen flood warning and evacuation systems.</p>","PeriodicalId":49294,"journal":{"name":"Journal of Flood Risk Management","volume":"18 1","pages":""},"PeriodicalIF":3.0000,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jfr3.70026","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Flood Risk Management","FirstCategoryId":"93","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/jfr3.70026","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
Development of Flash Flood Forecasting System for Small and Medium-Sized Rivers
Owing to the increased frequency of short-duration extreme rainfall events caused by climate change, peak flood flows are expected to increase substantially in small and medium-sized rivers (SMRs) with a short time of concentration for a catchment (Tc). Accurate flood forecasts and corresponding evacuation are effective in reducing the number of casualties caused by flash floods in SMRs. Currently, flood forecasting using observed rainfall in SMRs has a short lead time, which often delays the issuance of evacuation orders by local governments. Moreover, the large number of SMRs necessitates a system that can be widely used by local governments for disaster response tasks, such as issuing evacuation orders. Therefore, we developed a system that can accurately predict when river water levels will reach the Flood Risk Level (FRL). This forecasting approach uses the rainfall–runoff–inundation (RRI) model and the H–Q equation. The parameters in the RRI model were optimized using the Shuffled Complex Evolution algorithm developed at the University of Arizona (SCE-UA) to reduce the required time and effort. The system uses real-time water level observation data to sequentially modify the basin state quantities in the RRI model using the particle filter method to improve the water level forecast accuracy. The system was implemented in 200 rivers in Japan with diverse rainfall and geological characteristics and was tested during the flood season. Accuracy verification was conducted when the forecasted water levels were operated within a range of ± 50 cm. The results showed that 75% of the flood events could be forecasted more than 2 h before reaching the FRLs. Furthermore, 89% of the flood events could be predicted with a lead time (LT; time that water levels reach the FRL—time of first forecast) of 2 h or more or a lead time equal to the Tc or more. These findings show that this system has the potential to enhance and strengthen flood warning and evacuation systems.
期刊介绍：
Journal of Flood Risk Management provides an international platform for knowledge sharing in all areas related to flood risk. Its explicit aim is to disseminate ideas across the range of disciplines where flood related research is carried out and it provides content ranging from leading edge academic papers to applied content with the practitioner in mind.
Readers and authors come from a wide background and include hydrologists, meteorologists, geographers, geomorphologists, conservationists, civil engineers, social scientists, policy makers, insurers and practitioners. They share an interest in managing the complex interactions between the many skills and disciplines that underpin the management of flood risk across the world.
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
