Flood Risk Area

Flood Inundation Assumed Area Map for the Tamagawa, Asakawa, and Oguragawa Rivers

On May 30, 2016, the Ministry of Land, Infrastructure, Transport and Tourism designated and announced the "Flood Inundation Assumed Areas" for the Tamagawa, Asakawa, and Oguragawa rivers in the Tamagawa river system in the event of flooding.

• Tamagawa Flood Inundation Assumed Area Map (Maximum Expected Scale)(External Link)

This map shows the results of a simulation of the areas that would be flooded and the depth of flooding in the event of the maximum expected rainfall (total rainfall of 588mm over 48 hours in the Tamagawa River basin) due to external water overflow.

Flood Inundation Simulation

You can view the simulation results of flood conditions in the event of heavy rain causing the levees of the Tamagawa, Asakawa, and Ogurigawa rivers to break.

• Tamagawa Flood Simulation (Keihin River Office)(External Link)

Tamagawa Flood Hazard Map

The Inagi Disaster Prevention Guide includes the Tamagawa Flood Hazard Map.

• Tamagawa Flood Hazard Map (PDF 1.9MB)

Flood Inundation Assumption Area Map for the Asakawa Basin, Ogurigawa, and Misawa River Basins

Tokyo Metropolitan Government has published the Flood Inundation Assumption Area Map for the Asakawa Basin, Ogurigawa, and Misawa River Basins (February 2024).

• Flood Inundation Assumption Area Map for Asakawa Basin, Oguri River, and Misawa River Watersheds (Assumed Maximum Scale)(External Link)

This map shows the simulation results of areas and depths of inundation caused by external water flooding when heavy rain falls with a maximum hourly rainfall of 153mm and a total 24-hour rainfall of 690mm in the Asakawa Basin and Oguri River watershed, and a maximum hourly rainfall of 152mm and a total 24-hour rainfall of 690mm in the Misawa River watershed.

Misawa River Flood Hazard Map

The Inagi Disaster Prevention Guide includes the Misawa River Flood Hazard Map.

• Misawa River Flood Hazard Map (PDF 1.9MB)

Inquiries about the Flood Inundation Assumption Area Map

• Flood Inundation Assumption Area Map (Keihin River Office)(External Link)
  Ministry of Land, Infrastructure, Transport and Tourism Kanto Regional Development Bureau Keihin River Office (Phone: 045-503-4000)
• Asakawa Area, Oguri River and Misawa River Basin Flood Inundation Assumption Area Map (Tokyo Metropolitan Government Bureau of Construction)(External Link)
  Tokyo Metropolitan Government Bureau of Construction River Disaster Prevention Division Disaster Prevention Section (Phone: 03-5320-5190)