RIVERS IN JAPAN 1998

RIVERS IN JAPAN 1998

 

CONTENTS

I        Geographical Characteristic

              Water management

              The Land and itfs River

              Flood and sediment disaster

 

II       Flood and Erosion control

              Flood damage prevention

              Urbanization and flood damage

              Integrated flood control measures

              Housing development and flood control

              Super levees for flood preparedness and

 community development

              The use of dams for flood control

              Preventing sediment disasters

              Coastline protection

              Disaster recovery

             

III     Water Resources

              Characteristic water resource

              Serious consequences of drought

              Diverse approaches to water resources

 development

 

IV      Ecological Considerations

              Improving water quality

              Conservation

              Restoring livable environments

 

V       The 1997 Amendment to the River Law

              Outline of the 1997 Amendment to the River Law

              New system for planning river improvement

              Drought conciliation

              Fluvial forestation

              Preventing illegal mooring

              Preventing accidental water pollution

 

I        GEOGRAPHICAL CHARACTERISTIC

              Japan, tough blessed with abundant natural beauty, is plagued by frequent natural perils including floods, landslides, earthquakes, tidal waves, and volcanic eruptions. With the enactment of The River Law in 1896, a regular flood control plan was established. In recent years, however, with urbanization resulting in greater damage from natural disasters, river maintenance projects have become even more essential.

 

              Water management

              Natural disasters are common in Japan. Urbanization has created new types of disasters (disruption of inner water, the triggering of landslides, etc) and increased water demand. Calamities and sudden water shortages can paralyze cities and impact heavily on everyday and economics activities. We implement various projects to protect the land and people and to create safe and comfortable living environments within the active society.

 

              The Land and itfs River

Rivers in Japan are short and steep and flow rapidly and violently. Moreover, the ratio between the normal volume of the flow and that during a storm is extremely great.

Seeing the Joganji River in Toyama prefecture, Johannes de Rijke exclaimed, gRivers in Japan are like waterfallsh.

A Dutch engineer hired during the Meiji Era (1868 –19111), de Rijke contributed substantially to flood project in major rivers in Japan, such as the Kiso, the Nagara, and the Ibi Rivers, known as the gthree rivers of Kisoh.

De Rijkefs statement is an apt description. Rivers in Japan characteristically  flow directly from mountain to sea. A great amount of rains falls on the Japanese archipelago during the rainy season (heavy rains of June and July) and typhoon seasons; and during periods of intensive rainfall, even a small stream that usually runs low may become a raging torrent.