## (4) Stronger tsunami measures for sewerage

Since sewerage had little experience in being damaged by tsunami in the past, full measures had not necessarily been taken in advance to cope with tsunami, and much of the sewerage, including mechanical and electrical equipment, was damaged, destroyed, or washed away by the recent earthquake. In the future, the Ministry will pay attention so that sewerage can be returned to normal quickly even if mechanical and electrical equipment is destroyed or washed away and that sewage can be drained even if the water level at treatment and pump stations falls due to land subsidence.

Chart. 56 Standard Ability of Sewerage to Resist Tsunami of the Largest Class

Facility type	Duct facilities	Pump stations	Treatment stations
Classification of functions	Overall functions
Basic functions	Other functions
Preventing sewage from flowing backward	Pumping	Pumping Disinfection	Precipitation Dehydration	Functions other than those listed to the left
Ability to resist tsunami	“Must be maintained” without fail even if hit by disaster	Should be recovered swiftly though the temporary stoppage of functions is acceptable	Should be recovered early though the temporary stoppage of functions is acceptable
Unit facility	Sluiceway facilities	Pumping facilities	Pumping facilities Disinfection facilities	Precipitation facilities Dehydration facilities
Example of response measures	- Major structures are installed at locations higher than expected flood levels.
- Openings are installed at locations higher than expected flood levels.
- Openings are covered by protective walls.
- Electrical and mechanical equipment is installed at locations higher than expected flood levels.	- Installation of tsunami-resistant walls and making openings watertight (watertight doors).
- Installation of tsunami-resistant walls and making electrical and mechanical equipment watertight
- Securing extra machines (electrical and mechanical equipment)	- Other measures

## (5) Starting to take tsunami measures for airports

Each airport had steadily taken measures to make it earthquake-resistant, but their efforts had not been sufficient in terms of response to possible tsunami. For this reason, based on the lessons learned from the recent earthquake, the airport authorities, which are likely to be hit by tsunami, will establish emergency evacuation systems on the assumption that their airports may be stricken by tsunami of the largest class. In order to protect the lives of passengers in the airport, related airport personnel, and evacuees from neighboring areas as well as those of passengers on airplanes running on the ground by giving appropriate instructions and information to the airplanes, some airports, including the Tokyo International Airport, have built such systems by establishing standards for decisions on whether to order evacuation, designating evacuation sites, and examining in concrete terms methods to handle evacuees, provide information, and take other measures as well as by establishing implementation systems, defining division of roles, securing methods to obtain and communicate information, and conducting drills. Other airports will also gradually establish such systems in the future. If hit by tsunami, the airport authorities will swiftly establish systems of cooperation with various related organizations engaged in recovery efforts so that their airports start to demonstrate their functions as a hub of emergency and life-saving activities and emergency supplies transport within three days of disaster occurrence, and will remove driftage flowing into the airport, install temporary power generation equipment, and take other necessary measures. They will also recover their fences to maintain security areas required for the operation of commercial flights early on.

Six airports---Sendai, Haneda, Chubu, Kansai, Kochi, and Miyazaki---will take such measures as drawing up work plans to enable early recovery as described above.

## Column Sendai Airport Served as a Hub of Transport of Emergency Supplies

After the Great East Japan Earthquake, due to the tsunami that followed it, Sendai Airport saw over 2,000 damaged cars and some 370,000 m $ ^{3} $ of debris drift on to its grounds, including runways, but thanks to the urgent recovery efforts of the Self-Defense Forces, American armed forces, administrative agencies, and related parties from the private sector, helicopters began to operate at the airport on the fourth day after the disaster, and transport aircraft from American armed forces, etc., did so on the fifth day. Thus the Sendai Airport served as a hub of transport of rescue suppliers.

Source: MLIT