| Abstract from DBPedia | A flood is an overflow of water (or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrology and are of significant concern in agriculture, civil engineering and public health. Human changes to the environment often increase the intensity and frequency of flooding, for example land use changes such as deforestation and removal of wetlands, changes in waterway course or flood controls such as with levees, and larger environmental issues such as climate change and sea level rise. In particular climate change's increased rainfall and extreme weather events increases the severity of other causes for flooding, resulting in more intense floods and increased flood risk. Flooding may occur as an overflow of water from water bodies, such as a river, lake, or ocean, in which the water overtops or breaks levees, resulting in some of that water escaping its usual boundaries, or it may occur due to an accumulation of rainwater on saturated ground in an areal flood. While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, these changes in size are unlikely to be considered significant unless they flood property or drown domestic animals. Floods can also occur in rivers when the flow rate exceeds the capacity of the river channel, particularly at bends or meanders in the waterway. Floods often cause damage to homes and businesses if they are in the natural flood plains of rivers. While riverine flood damage can be eliminated by moving away from rivers and other bodies of water, people have traditionally lived and worked by rivers because the land is usually flat and fertile and because rivers provide easy travel and access to commerce and industry. Flooding can lead to secondary consequences in addition to damage to property, such as long-term displacement of residents and creating increased spread of waterborne diseases and vector-bourne disesases transmitted by mosquitos.洪水（こうずい、英語: flood）とは、通常の境界（範囲）を超えて大量の水があふれることであり、特に通常は乾いている土地へと水があふれ出すことが多い。常態では水が無い陸地が水によって覆われること。河川管理上においては単純に豪雨などで水位が上昇し流速が速くなることを洪水と呼ぶことがあり、日本国国土交通省の定義もこれに準ずる。この場合、河川から水のあふれ出す「氾濫」は洪水のうちの一つの現象となる。一方日本国気象庁の定義においては、増水により河川敷内部、さらには堤防の外にまで水があふれ出すことを指す。 (Source: http://dbpedia.org/resource/Flood) |
