yousef abu baker المدير العام
عدد المساهمات : 369 تاريخ التسجيل : 20/01/2011
| موضوع: حث عن فيضانات بالانجليزى الأحد أبريل 17, 2011 3:04 pm | |
| The definition of flood Flood is a natural phenomenon occurs when the water level more than in any river; to exceed the level of its banks Vitgy it, the faster the water flow from upstream to downstream flooding increased. The statistics showed the increased intensity of floods in the latter half of the twentieth century, Venhr "Yangtze" in China for example, was awash with sharply since centuries once every twenty years is now awash with a rate of nine years out of ten, and the river "Rhine" in Germany has increased only 4 times between (1900.1977) 7.6 meters above flood level, while this level increased to ten times in the period between 1987.1996.
Causes Pointed fingers to the humanitarian activities as a direct cause of the wave of flooding that has swept Eastern and Central Europe, as confirmed by environmental experts that global warming is also one of the most important causes of the flooding. In addition, there are many other reasons that led to the growing phenomenon of floods, including: 1 - occurrence of earthquakes in the seabed. 2 - melting of ice in the rivers and Ansbabh. 3 - strong winds and hurricanes. 4 - rainfall levels 5 - the uprooting of forests and plants that live near rivers, forests consume large quantities of water and when removed less consumption of water, causing flooding. The removal of large areas of forest that lies at the headwaters of the rivers of the most important causes of floods, forests were consumed large quantities of water is not consumed by agriculture, regular or grassland, of course, thus resulting in lack of water consumption in the headwaters of rivers to increase the amount of water that descends through the streams that Fifid river river severely. Trees and forests play an important role in the consumption of water in the headwaters of rivers, trees Voorac retain some rainwater to evaporate directly into the air, and reduces the impact of rain on the soil of Qatar, who works on the dismantling of the soil and thus its shelf in the river bed. The roots of these trees, they absorb water from the soil making the soil drier becomes more likely to absorb more water from the rain as to maintain the cohesion of the soil and stability and reduce the movement of silt and sediment that are impeding the course of the river (reduce the depth of Visa to less water Fifid least increase in water level). Therefore, the absence of forests led to the absence of a major water consumers, has also led to the disintegration of the soil and easily washed in the river bed and therefore removed most of the obstacles that were impeding the river in the flock into effect quickly across the waterway, and the massive flooding occurs.
Damages:
They lead to losses and damage to a variety of (human and material, and): 1 - demolition of homes and displacing thousands of people and make them homeless. 2 - corrupting the farmer and agricultural crops. 3 - It is not only the strength of the direct damages resulting from the severe rush of water and supply of 4 - only. But also cause the spread of diseases and epidemics in the affected areas and among the population
And the danger hovering over some Pacific islands such as the Republic of Kiribati Almhadp disappear at any moment Fbhdot strongly moderate flooding of the island will disappear in the depths of the sea.
According to the report will be Asia, the scene of human drama of the phenomenon of climate change, almost half of its population living in coastal areas are most vulnerable to natural disasters such as floods, hurricanes, caused by climate change. This means that nearly two thirds of the world's population will find themselves on the front line with the risks of climate change. And calls for environmental agencies and major industrial countries including the United Kingdom to take effective steps to reduce the emission of greenhouse gases blamed for global warming by at least 80% by 2050.
Benefits:
Flood losses and many benefits and few of the benefits: 1 - The flooding river fed groundwater reservoirs. 2 - water-saturated ground, which makes the land fertile for agriculture, which will help the prosperity of agricultural activity in the world.
Factors affecting the flood: Heavy rainfall and affect a variety of factors such as: the length of time of precipitation, the magnitude of water drops (the intensity and abundance). And permeability of the soil, and the extent of moisture and the extent of its decline and the availability of vegetation cover, melting snow, hurricanes occur, the phenomenon of a tsunami and the collapse of dams.
To predict the occurrence of floods: The use of statistical techniques Use maps and remote sensing techniques to demonstrate the extension of the flood. Monitoring the evolution of the storm of rain during the weather forecast or early warning devices. The effects of flooding: Affect flooding in the areas in which they occur, and cause an imbalance in the ecological balance through the influence of the components of the ecosystem and the effects attributable to the amount of quantity and speed of flow. Negative effects: The elimination of agricultural soils and changing composition and erosion areas sloping. Eliminated with the organisms that live in the course of the river and its banks in the destructive effects of buildings and facilities, roads and existing industries in place. Damage to physical, social and economic development of the human person. Positive effects: Remove the waste stream ecosystem from the water. Exchange of pathogens to the sea, where they are disposed of because of the salinity waters. Feeding aquifers. Addressing the threat of flooding: Can reduce the impact of floods by following the following: Maintain the vegetation existing building retaining walls, planting trees around the plowing is perpendicular with the slope to build dams in the potential sites of flooding to identify a specific area of the stream water or the river so that is a sanctuary of the valley, depending on how high the floodwaters, and prevent the establishment of facilities residential or industrial it.
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