Information supply

This website provides observed information of the rain gauges and the water level gauges of the rivers in Tokyo in real time.
Please update yourself with the rainfall or river water rising condition to carry out flood prevention measures.

Numerical data, simple tables, graphs and river images are not subject to copyright and may be freely used, but please mention the source when using the content.
If you use content that has been edited or processed by you, please indicate that you have edited or processed it in addition to the above source. Furthermore, please do not publish or use the information you edited or processed in a manner as if it was created by the Tokyo Metropolitan Government.

Information may not be displayed or abnormal values may be displayed when the observation equipment is under maintenance or in failure.
Depending on the circumstances, the administrator may change, suspend or cancel the information supply without notice.
The information provider bears no responsibility for any inconvenience or losses which may occur related to activities carried out based on this information.
Flood prevention measures must be carried out promptly when warnings, alarms, special alarms are announced. Please refrain from making inquiries by phone or other means.
Based on the river images and other conditions such as water level and rainfall, the flood risk will be assessed comprehensively and announced. Therefore, the river image may differ from the announced condition.

This website uses JavaScript. Please make sure JavaScript is enabled on your browser.
We recommend a screen size of at least "375 pixels."
The display of the screen may vary depending on your browser and display driver.

The top page displays information on rainfall, river water levels and floodgate tide levels, river camera installation locations, and weather information such as warnings, alarms and special alarms.
Selecting an area and a municipality will display the rainfall and river water level information and the river camera installation locations in that area.

Display the sediment disaster alarm information, flood forecast river information, water level well-known river information, and storm surge flooding information announced in Tokyo.
Clicking the blue- or red-banded button at the top of the screen will display more information.

Top page

Selecting an icon of the rainfall observatory will display the details page.
The 10-minute display on the initial screen of the rainfall graph shows the history of the past four hours from the displayed time.
When 1 minute is selected on the rainfall graph, the history of the past 24 minutes from the displayed time is displayed.
When 1 hour is selected on the rainfall graph, the history of the past 24 hours from the displayed time is displayed.

Rainfall information

Selecting the icon of the water level observatory will display the details page.
The 10-minute display on the initial screen of the water level graph shows the history of the past four hours from the displayed time.
When 1 minute is selected on the water level graph, the history of the past 24 minutes from the displayed time is displayed.
Since the cross section of the river is a schematic representation, it differs from the actual cross-sectional situation.

Water level information

Selecting an icon showing the river camera installation location will display the details page.
On the river image screen, you can select and display images from the past 24 hours by button operation, etc.
The shooting range and location of river images are subject to change due to equipment inspections, flood prevention activities, etc.
If there is a video page button on the river image screen, selecting the "Video Page" will open the live video page available on YouTube.

River camera information

The inflow into the regulating reservoir mainly contributes to lowering of the river water level downstream from the regulating reservoir. In the event of a heavy rainfall, please follow evacuation information from the local government and take appropriate evacuation actions by referring to river flooding and water level information.
Stored water is promptly drained to prepare for the next rainfall while checking river, weather and other conditions.
Storage ratio and storage start time are provisional values.
In the system, the time when the prescribed storage ratio set for each regulating reservoir is exceeded is expressed as the storage start time.

Reservoir information