Inland water hazard map

Hazard maps of floods, inland waters, and high tides are compiled as "Inundation Hazard Map".
Please also check the flood hazard map and high tides hazard map information along with the inland water hazard map.

It is a map that summarizes various information such as areas where flooding from sewer pipes and waterways is expected during heavy rain and the depth of flooding.
This map is used for smooth evacuation behavior against inundation and improvement of disaster prevention awareness during normal times.

Please refer to the following "PR videos" and "PR materials" for explanations on maps and explanations on how to use them.
PR video ⇒ "Preparing for heavy rain-Utilization of inland water hazard map-(external site)"
PR document ⇒ "Let's use the inland water hazard map to prepare for the increasing heavy rain! （PDF：1,317KB）」
※Inland water: Heavy rain fills sewer pipes and waterways, and overflowing water from manholes and rainwater masu
※Flood: Heavy rain continues and the water level of the river rises, exceeding the embankment and the levee breaks, causing river water to overflow.

From June 28, 2021, we revised the inland water hazard map when the largest possible rainfall (153 mm per hour) occurs.

For searches from Address, etc., or for detailed maps.
Please utilize "Yokohama-shi administration map reporting system" (Wai Wai disaster prevention map) (outside site)".
・Residential land lower than roads, such as basements and underground parking lots, there is a risk of rainwater entering regardless of the degree of flooding.
・Depending on the strength of the rain and how to descend, the flooded area and depth of inundation may differ from expectations.
・The inundation assumption of the inland water hazard map is created reflecting the maintenance status of rivers and sewers at the end of FY2018.
・In the "Yokohama City Administrative Map Information Providing System (Wai Wai Disaster Prevention Map)" allows you to check the inundation depth of any point calculated by the inundation simulation and the ground height (TP) used for calculation. Please refer to "Click here (PDF: 1,028KB)" for confirmation method.

Due to a partial revision of the Enforcement Regulations of the Housing Lots and Buildings Transaction Business Law (enforced on August 28, 2020), the location of the residential land or building to be dealt with in the flood hazard map created based on the Flood Control Law will be newly added to important matters explanation. Will be positioned as

The inland water hazard map of Yokohama City is not based on the Flood Control Law, but when dealing with residential land or buildings, present this inland water hazard map is presented, and the other party of the transaction grasps the flood risk, We ask that you provide information on the location of the residential land and buildings subject to the transaction so that it can be used for evacuation actions.

[Important Notice]
The inland water hazard map is not limited to the assumption of leaching in your area.

・Methods for obtaining necessary information in the event of a disaster and daily preparation
・Precautions for heavy rain and how to think about evacuation
・Mechanisms of inland water flooding and flooding (river flooding)
・Actions to be taken when evacuation information is issued
It describes the important thing. Please be sure to check it along with the map.

↓↓↓Click here to download.↓↓↓

Information side (common to all wards) (PDF: 5,660KB)

※The map surface of each ward has been updated according to the contents of the inundation hazard map (update date: June 1, 2022)
　We have created a paper map as a flood (inland water, flood, high tides) hazard map. When you want reading on paper, please see in city hall the third floor citizen information room center.
　Click here for the inundation hazard map

Disaster in Yokohama City
(You can check the flood history etc. here.)
Frequently Asked Questions (PDF: 705KB)
(Frequently Asked Questions have been updated.) Update date: June 30, 2023)
Past inland Water Hazard Map
(You can check past inland water hazard maps here.)
Inland water hazard map interview video (outside site)
(Interview with the National Research and Development Agency Disaster Prevention Research Institute for Disaster Prevention)