Barclays shares expertise on disaster preparedness

Nov. 16, 2018

Though most disaster preparedness in Tokyo focuses on what to do in the case of an earthquake or tsunami, BCCJ Platinum Member Barclays has shared that the probability of a flood is much higher. At a BCCJ risk seminar, in October, the firm outlined why Tokyo is at risk of flooding, what residents might expect if a flood occurs and how to be prepared.

Yasutake Sayanagi, vice president of Group Resilience at Barclays and author of reports on threats and pandemics, began by pointing out the precedent of flooding in Tokyo. From 2000 to 2015, there were 104 floods in Tokyo affecting a total area of 661 ha.

The cause was a combination of heavy rain in the mountains around Tokyo and in the city itself that exceeded the capacity of dams, rivers and the drainage system, and a high tide that pushed water ashore.

In addition, about 20% of typhoons to make landfall in Japan in the past three years have impacted Tokyo, bringing strong winds and low pressure as well as high levels of precipitation.


What’s behind the flood risk?

According to Sayanagi, Tokyo is at serious risk of flooding because of its location and geography. Yet, within its 23 wards, the likelihood of flooding varies.

Much of the city’s Shitamachi area (east of the Keihin-Tohoku line) which was under the sea 6,000 years ago, is built on soft soil and sand. Most of it is less than 5 metres above sea level, making it prone to flooding and liquefaction.

The Yamanote area (west of the Keihin-Tohoku line) meanwhile, is built on hard soil and is mostly 20–40 metres above sea level.

The path of the River Tone exacerbates the risk for the Shitamachi area. Until about 400 years ago, the river flowed into Tokyo Bay, but the Tokugawa shogun diverted it to flow through Chiba Prefecture to the Pacific Ocean in order to create more dry land in the east of the then-fledgling city. It therefore passes through huge swathes of low-laying land.


How might Tokyo be affected?

Though the Shitamachi area faces the greatest threat, Sayanagi pointed out that the Yamanote area is not without risk. Some parts of Minato Ward, for example, would be at risk of flood water to a depth of 0.5–1 metre.

In terms of transport and infrastructure, the worst scenario shows that the Tozai and Hibiya subway lines would be inundated with water within 15 hours of a breach of the River Ara. Other subways lines would be flooded within 24 hours.

After the floodwater subsides, Tokyo would be affected by sewage and dirty water left behind as well as impaired access to food and water due to distribution difficulties. Both issues could impact the health and safety of residents.

In addition, parts of Shitamachi are at high risk of fire due to the large number of wooden buildings in close proximity and narrow roads that may impede or prevent access for fire engines should an outbreak occur.


How can we be prepared?

As a starting point, Sayanagi recommended everyone pick up a hazard map covering the location of their home, workplace and children’s school, which are available at any of Tokyo’s 23 ward offices. These maps provide an accurate representation of risk, he said, pointing out that the degree of flooding throughout Hiroshima in July 2018 was almost the same as that shown as high risk on its hazard map.

He suggested then reconsidering where to live according to the level of risk and ease of evacuation.

“Moving to an area of less risk before a disaster occurs makes sense. This is the so-called pre-evacuation concept,” he said, adding that it is important to prioritise the safety of one’s family over living in a high-risk area that boasts a nice view or an easy commute.

Barclays has developed a Home BCP (Business Contingency Plan) for staff to complete with their families. Sayanagi encouraged attendees to also make one.

Each Home BCP is pocket-sized for ease of carrying and contains the following information about each family member:

  • Contact information (mobile phone, email, landline and social networks)
  • Typical daytime location
  • Medical conditions 

Other details include:

  • Primary and secondary meeting points
  • Method of communicating with family members
  • Pick-up plan for children, including school contact details
  • Embassy information
  • Emergency contact numbers

Sayanagi suggested attendees get a landline installed in their home as they are more stable than mobile lines, which may be out of use within 30 minutes of a disaster occurring. For this reason, it is also vital for families to decide where to meet each other and what to do if nobody is available to do the school pick-up.

As Tokyo Metropolitan Police Department will make all major roads in Tokyo accessible to only emergency vehicles following a disaster, evacuation plans and assembly points should be planned accordingly.

Sayanagi recommended storing emergency items, including water and food for 3–5 days as well as money, a first-aid kit, a torch and plastic bags and a deodoriser for using the toilet.

As adults require two litres of water per day, keeping a large stock of long-life PET bottles or a water server would be useful. Tap water is potable for three days following a disaster, after which it can be used for bathing. Food should be pre-cooked, high-calorie, nutritionally balanced and have a long life. Dishes can be covered in wrap to avoid use of water.

Being ready to secure property or evacuate is critical, he added. While there is a time lag in the translation of weather warnings and advisories into English, he suggested that everyone closely monitor municipal updates when there is an impending risk of disaster. 

More details can be found on the Tokyo Metropolitan Government’s Disaster Prevention Website:

Full presentation courtesy of Sayanagi Barclays Japan


Produced by Sterling Content for the BCCJ