Introducing One Concern’s live compound flood forecast pipeline in Japan

Dr. Yi Liu, Data Scientist at One Concern

Making disasters less disastrous is One Concern’s core mission, and one specific natural disaster we focus on is flooding. Currently, an effort is well underway at One Concern to deploy a national live compound flood forecast pipeline in Japan, as an expansion of last year’s pilot flood pipeline in Kumamoto City, Japan, a successful proof of concept product. The ability to forecast compound floods in a real-time manner with sufficient lead time is critical for emergency managers to make well-informed decisions about evacuation and resource allocation before a flood event. To that end, our Japan flood pipeline is designed to ingest weather forecast data (including rainfall, temperature, wind and pressure etc.) whenever available automatically and make live forecasts of hourly compound flood maps with an integrated consideration of storm surge, streamflow and urban runoff with a forecast period of up to 72 hours (Figure 1). A flood alerting mechanism that triggers the inundation prediction is implemented in the pipeline. The forecasted flood depths are then used to calculate impact statistics such as overflow points, buildings inundated and population affected.

Figure 1. Overview of the Japan flood pipeline.
  • Inundation model: a large-scale SCHISM inundation model co-developed with Virginia Institute of Marine Science was used. In Nagano, our inundation model was able to capture the inundation pattern of the riverine overflow flooding of Chikuma River when compared with observation (Figure 3) with an overall hit rate of 0.8 when using observed streamflow and reanalysis rainfall as weather input. Details and more results are included in future publications.
Figure 2. Track of Typhoon Hagibis and locations of validation results shown here.
Figure 3. Observed flooding in Chikuma River, Nagano by a) a snapshot of drone video and b) inundation estimation stage map by the Geospatial Information Authority Of Japan.

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