SENDAI -Towards a Disaster-Resilient and Environmentally-Friendly City

Sendai City is taking comprehensive structural and non-structural measures such as improving business operations and developing business continuity plans (BCP) as well as improving the earthquake resilience of facilities and equipment, and disaster measures for essential utilities(*), public transportation, and public facilities in anticipation of recovery and reconstruction of the city when disasters occur. *Electricity is supplied by private operators.

Water Supply

Sendai City has taken many different measures based on the lessons we learned from the 1978 Miyagi-ken-oki earthquake, such as using water pipelines that meet a defined level of earthquake resilience when renewing or establishing new pipelines. While these measures had a definite effect in helping the city to recover quickly during the Great East Japan Earthquake, the systems were greatly damaged in the disaster, with around half of the households in the city experiencing water failure. We verified the efficiency of, and problems with, our previous disaster countermeasures based on our experiences, and are working to build a strong water supply that does not fail in disasters.

We are currently improving the earthquake resilience of water purification plants, distribution centers, and pipelines to disaster base hospitals, etc. We are also taking countermeasures against long-term power outages such as increasing the number of fuel tanks for standby generators at water purification plants, and important water supply centers and pumping stations.
Furthermore, we are working to improve disaster responses connected to “self-help” and “mutual aid” in local communities. For example, at elementary schools designated as evacuation centers, we are installing water hydrants for use during disasters that local residents can use to establish and utilize water distribution centers by themselves, and are explaining how to use them at disaster response drills in each community, as well as promoting private water storage.

 

Primary Targets for Disaster Countermeasures Regarding The Water Supply

	End of FY 2014	Target for FY 2019
Percentage of earthquake resilient water pipelines	86.5%	87%
Earthquake resilient water pipelines to disaster base hospitals, etc.	19 piping systems	30 or more piping systems
Percentage of earthquake resilient distribution reservoirs	15.5%	50%
Number of water hydrants available for use during disasters	94	180 or more
Percentage of major water purification plants with long-term power outage countermeasures	25%	100%

 

Sewage Systems

Sendai has a long history of sewage works, with work starting on the sewerage system in 1899, preceded only by Tokyo and Osaka. In 1957 Sendai received national approval of its business plan and started work on a modern sewerage system. As a result, the service coverage ratio for sewerage reached 99.5% by FY 2014. Continuing with disaster countermeasures, we have adopted asset management strategies to systematically manage the fees that accompany increasing the number of facilities and the maintenance of deteriorating facilities.

Sendai’s coastal sewage treatment facilities were greatly damaged by the tsunami that followed the Great East Japan Earthquake. However, as we had carried out disaster measures such as improving the earthquake resilience of sewage pipes, improving disaster support systems, and formulating a business continuity plan (BCP), no sewage overflowed in the city after the earthquake, and we were able to start recovery work without restricting usage.
We followed the idea of “Building Back Better” in the reconstruction of the damaged Minami-Gamo Wastewater Treatment Plant. It has not been restored to its original state, but has had its banks raised and has been fitted with waterproof doors to protect it against tsunamis as large as the one seen during the Great East Japan Earthquake. In addition, we installed solar power and hydro-electric power generators as emergency power sources. We are also improving both our structural and non-structural disaster measures by aiming to make 40.6% of sewage pipes and 71.1% of sewage facilities earthquake-resilient by 2020, and by formulating a BCP based on our experiences of the earthquake.
We are not only taking the earthquake countermeasures above, but we are also constructing sewer tunnels (storm sewer pipes), storm-water reservoirs for flood control, and pumping stations as countermeasures against the risk of floods during heavy rainfall, which has become higher in recent years, particularly in the center of the city.

For information about the sewerage related disaster countermeasures, see ““Efforts for Making Sendai a Disaster-Resilient and Environmentally-Friendly City – Urban Development.”

 

Earthquake Resilience Rate of Sewage Pipes and Facilities

 

	2014	Target for 2020
Percentage of earthquake-resilient sewage pipes	33.8%	40.6%
Percentage of earthquake-resistant sewage facilities	6.7%	71.1%

 

City Gas

We have taken measures against earthquakes based on lessons learned from the periodic earthquakes that occur in Sendai to prevent secondary disasters caused by gas leaks, and to provide a stable city gas supply. These measures include making gas pipes earthquake-resilient, creating duplicate lines and blocks of supply lines, as well as collaborating with the Japan Gas Association and municipal gas companies all around the country. The manufacturing and supply facilities of gas companies in Japan were greatly damaged for the first time by the Great East Japan Earthquake and tsunami. The gas supply was unavoidably cut off for around 360,000 households in the city, but we were able to restore the supply to 90% of households in about a month, which was earlier than planned.

However, as the complete halt of the gas supply greatly affected residents’ lives, we are continuing to take structural measures such as making gas piping earthquake resilient, taking measures against tsunamis at manufacturing facilities, and increasing the number of emergency gas receiving facilities so that gas can be safely and reliably supplied in any circumstances during reconstruction. We are also taking non-structural measures such as subdividing work areas and revising disaster measure manuals.

Earthquake Resilience Rate of Gas Pipes

 

Schools

Since 1996 we have been improving the earthquake resilience of schools, which are not only where young students gather, but also become local evacuation centers during emergencies. We have done this by evaluating earthquake resilience and carrying out construction to strengthen school buildings against earthquakes. As the earthquake resilience rate was 99.9% at the time of the Great East Japan Earthquake, none of the school buildings collapsed in the earthquake, and no students under school supervision were injured. We have continued to implement measures since then, and the earthquake resilience rate reached 100% in 2011.

Furthermore, as loss of power supply and securing safety at evacuation centers became an issue during the Great East Japan Earthquake, we have taken measures to secure a power supply by installing solar power generators and batteries, and to prevent ceilings from collapsing in indoor gymnasiums and so on. We have also placed a disaster officer in all elementary and junior high schools, and have created and carried out year-long disaster prevention education plans, as well as joint disaster prevention education with local residents, parents and guardians. We have also distributed original supplementary reading materials for DRR education to all students since FY 2012. These materials are revised and improved every year, and are used in all subjects and areas.

For information about disaster prevention education in Sendai, see “Efforts for Making Sendai a Disaster-Resilient and Environmentally-Friendly City – Human Capacity Building – Promotion of Sendai’s Disaster Prevention Education”

 

The Number of Solar Panel Systems and Storage Batteries at Designated Evacuation Centers

 

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