日本財団 図書館


A Disaster Prevention Support System Using River and the Ocean
 
Kunihiko HIRAI
Professor, Nagaoka Institute of Design
 
The maintenance of an extensive transport network system that organically ties up land, sea and air is a major point in the discussions involving earthquake counter measures. An infinite amount of small and large rivers flow through the plains on which large cities sit. These river routes need to be characterized as an extension to ocean routes and used more effectively to promote the improvement of the transportation network.
 
Disaster response operations integrating land, sea and air
 One of the greatest regrets about the 1995 Hanshin-Awaji Earthquake was that the region's abundant seas, port facilities, open spaces and airspace were not effectively utilized, in an integrated approach linking land, sea and air, to tackle the disaster. Though great efforts were made to incorporate land, sea and air routes into disaster-prevention planning, in each case the best routes were selected on an individual basis, not as cohesive parts of a comprehensive, three-route plan. In a truly integrated approach, earthquake barriers, for example, could be used not merely as barriers but as takeoff and landing facilities for helicopters and as transportation links for the delivery of goods and access to the open spaces where residents could take refuge. Admirably, Kobe's earthquake barriers withstood the quake, but it satisfied none of the other conditions listed above.
 Immediately after the earthquake, the development of a wide-area transportation network was proposed, linking land, sea and air and built in partnership between the public and private sector. In 1995 and 1996 the National Land Agency, Ministry of Transport and Ministry of Construction (now amalgamated in the Ministry of Land, Infrastructure and Transport (MLIT)) joined with the Fire Defense Agency (now Fire and Disaster Management Agency) to assess the cost of a comprehensive land development project for this purpose, in a study called the "survey to determine measures to promote the formation of an integrated land, sea and air network in the Tokyo area. " The survey dealt with four themes: the construction of disaster prevention bases for the Tokyo area as a center for wide-area support and other disaster prevention efforts extending across prefectural borders; formation of a river-based emergency transportation network; use of ports as centers for disaster prevention activities; and securing and distributing supplies of household water.
 Proceeding in parallel with these efforts is the Megafloat project, a plan to devise a large-scale floating structure for disaster prevention purposes. While the idea of creating an artificial, floating island in place of land has been around for over 20 years, it was only in the 1990s that the Transportation Technology Commission published findings that prompted real progress in research and development on the topic. The Commission was particularly interested in the fact that, while land-based structures sustained massive damage in the Hanshin-Awaji Earthquake, floating docks in shipyards emerged unscathed. That year a technical research consortium was formed, consisting of 17 shipbuilding and steelmaking companies. Megafloat was conceived as a mobile port facility and an "offshore wide-area disaster prevention base" for the Tokyo area, capable of supporting a river-based emergency transport network. Proving tests were conducted in Yokosuka Bay to float a prototype measuring 300m in length, 60m in width and 2m thick. After these tests, six units were linked together in l999 to create a Megafloat that was 1000m long, 60m wide (120m wide in some parts) and 3m thick (with a draft of 1m).
 As part of the Megafloat research effort, proving tests were conducted to assess its function as a disaster prevetion base and offshore airport. In autumn 2000, after the research and proving tests were completed, Megafloat was dismantled and put to other uses. In the ports of Osaka, Nagoya and Yokohama, these "minifloats" were docked with cargoes in the 1000t range and deployed as floating disaster-prevention bases with heliport capabilities.
 In a separate effort, the Research Institute for Ocean Economics (RIOE) initiated research on a "system for disaster prevention support from seas and rivers" immediately after the Hanshin-Awaji Earthquake. This proposal clearly demonstrated considerable promise. RIOE's report envisaged a 16m ship for river transport, with a draft of 1.5-2m when fully loaded and a height of 3m above the surface when empty. Assuming that the ship would require bridge clearance of 3m or more, waters at least 2m deep in dry season or at low tide and an upstream limit point of 20m (to enable turnarounds), the distance the vessel would be able to travel upriver from Tokyo Bay would be 29km on the Arakawa River, 22km on the Edogawa, 10km on the Tamagawa and 9km on the Tsurumigawa. Of these four, the river with the greatest potential utility is the Arakawa. Today a river bus operates along a 34km stretch of the Arakawa, with a capacity of 206 passengers and draft of 1.25m.
 Yet another plan, advanced by MLIT, calls for the construction of six river stations on each side of the Arakawa River, in a 30km stretch from the river's mouth. Dubbed the Arakawa River Station Plan, this scheme aims to facilitate river transportation during normal times and facilitate emergency response in the event of earthquakes or similar events. Although some safety issues remain to be solved regarding the use of rivers in disaster response, if these can be conquered a vast new transportation network can be opened up to serve the Tokyo area.
 
■The Arakawa River Station Plan
In MLIT's Arakawa River Station Plan, 12 "river stations" will be built along the Arakawa River, establishing an emergency transportation route to Tokyo Bay. Above is an artist's conception of the Toda river station with a 30m floating wharf.
 
A new urban transportation network for Japan's aging society
 If this river route is to be made available in times of crisis, measures must be taken to stimulate its use in normal times. Such a project amounts to nothing less than the creation of a new mode of river and marine transportation.
 If I may finish on a somewhat unrelated note, another new transportation network is emerging in the form of the three- and four-wheel electric vehicles, with a top speed of 6km/h, favored by the elderly today. In my own hometown, my mother loved her electric cart, and my 91-year-old father, taking her lead, uses one constantly to go shopping, visit the hospital or meet friends, These little vehicles are everywhere now, from big cities like Tokyo to regional centers like Nagaoka. Even though electric carts are only permitted on footpaths, many people cheerfully drive them on roads and highways. I believe the day is not far off when these little cars will throng city streets in huge numbers. Although it will start with brief journeys for daily tasks, I believe that elderly people living along Tokyo Bay, the banks of rivers and the Koto delta will soon use their beloved buggies to go shopping or sightseeing in Asakusa, Ginza, Tokyo Disneyland and Yokohama's Minato Mirai 21. The new water transportation systems should soon make such travel possible, in fact, it is hard to imagine such travel patterns without them.
 I believe that within 10 years we will see crowds of elderly people on their electric buggies. They will up and down rivers and along the shores of Tokyo Bay in countless craft both large and small, side-by-side with children and young adults on their bicycles.
(Ship & Ocean Newsletter No.26 September 5, 2001)
 
 
Yoshinori YAMANE
Mayor of Tamano City, Okayama Prefecture
 
Taking heed of the lessons taught by the "Great Kobe Earthquake", Tamano City of Okayama Prefecture, which faces the Seto Inland Sea, has begun to promote improved earthquake resistance of its harbor facilities, in order that the functions of its harbor aren't paralyzed by the occurrence of a major earthquake. Furthermore, a mutual support agreement has been formed by Tamano City with the harbor municipality of Chuo-ku, Tokyo. Through this agreement, a mutual cooperative arrangement, which includes the rescue of disaster victims, the provision of relief supplies and much other support, has been successfully set in place.
 
Applying the lessons of the Hanshin-Awaji Earthquake in harbor construction
 The City of Tamano is located on the shores of Japan's Inland Sea, or Setonaikai, in the eastern part of the sea known as Higashibisanseto. Since the 19th century the city's port, Uno, has been linked to the port of Takamatsu, across the Inland Sea in Shikoku, by a ferry service. For much of its recent history, the city's growth has been powered by its proximity to the ferry landing and by a local shipbuilding industry. In 1988 the Seto Ohashi Bridge was completed, linking Honshu, the mainisland of Japan and Shikoku. At the same time the old ferry service was replaced by a frequent local service, departing every 20 minutes day and night and calling at nearby islands such as Shodoshima and Naoshima in addition to Uno and Takamatsu.
 Before the bridge was constructed, the port of Uno was host to a constant stream of travelers passing over the straits. However, several levels of government are taking steps to boost seaborne traffic on the Inland Sea. In other regions, dedicated cargo berths are being built. To revive the movement of people by sea, the Ministry of Transportation (now MLIT) tabled a plan called Port Renaissance 21. Based on this plan, the area of the Uno ferry wharf was designated a "people port," meaning a port for the transportation of tourists, and efforts were stepped up to build a wharf for ocean-going cruise vessels and to modernize the ferry terminal. The development of the City of Tamano is now focused clearly on maritime traffic, as Tamano builds a new port culture that is open to the world.
 In setting a plan for the development of people ports in 2003, Tamano took great pains to design ports to provide solid backup in the event of major disasters. This decision was prompted when, in the wake of the Hanshin-Awaji Earthquake, Tamano sent relief supplies, firefighters and work vehicles to the scene of the disaster, but their arrival was delayed due to chaos on the roads. The city switched to marine transportation from the port of Uno to Kobe, but Kobe's port was devastated by the quake and scarcely able to function. This terrible experience underscored the crucial importance of earthquake-resistant port facilities.
 
■City of Tamano and surrounding area
 
Mutual Earthquake Support Agreement between port cities
 Recent moves in Japan to devolve powers to local governments are helping Japan's cities to develop greater autonomy and individuality. To develop stronger ties of commerce and promote the exchange of ideas, many cities are partnering with each other through sister-city agreements and inter-city exchanges. In Tamano, we quickly realized that Chuo-ku of Tokyo would be a good fit for such an agreement, for several reasons. First, many companies with places of business in Tamano have their head offices in Chuo-ku. Second, in the event of an earthquake or similar disaster, the chances of both locations being struck at the same time are slim, as the two cities are more than 700km apart. Finally, in the event that a disaster renders the roads impassable, the port of Harumi in Tokyo and the port of Uno in Tamano could be used to deliver relief supplies and dispatch relief workers by sea, provided that both ports made diligent preparations to implement earthquake-resistant infrastructure. Following discussions with Chuo-ku, in 1996 the City of Tamano and Chuo-ku concluded a Mutual Earthquake Support Agreement.
 The agreement offers a number of specific assurances. Our two cities agree to assist each other in the evacuation of disaster victims, to provide facilities for temporary supply, and to provide equipment and materials for rapid recovery from disasters, including vehicles for emergency relief efforts, food, drinking water and medical supplies. Medical and technical personnel will also be dispatched as required. We believe that the strong bonds of cooperation this agreement builds will foster a spirit of full and mutually rewarding exchange between the two cities, not only at the government level but among individual citizens and residents as well.
 As Mayor of Tamano, it is my basic responsibility to ensure the safety and security of residents. As the devolution of authority to local governments continues in Japan, I am confident that Chuo-ku, the heart of the nation's capital and the largest metropolis, and Tamano, a small city nestled in a beautiful natural environment, can complement each other to improve the quality of life for the people of both our constituencies.
(Ship & Ocean Newsletter No.26 September 5, 2001)
 
Signing ceremony for the Mutual Earthquake Support Agreement between Chuo-ku and Tamano City. Pictured are Mr.Yoshihide Yada, Mayor of Chou-ku(right) and the author(left).







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