Текст с заданиями по теме FLOOD

FLOODING IN SOUTH DAKOTA
What Is A Flood?
A flood occurs when water rises to flow over land that is normally dry. Floods happen in low-lying areas, such as valley bottoms, lake basins, and coastal areas. In South Dakota, flooding occurs mainly in valley bottoms, deep canyons, and lake basins when the amount of water moving through a river, or entering a lake, is so great that the natural or artificial banks can no longer contain all of the water. Therefore, the water overflows the banks of the river or lake and spreads out onto low-lying areas that are not normally covered with water.
What Causes A Flood?
In South Dakota, there are two main climatologically causes of flooding: runoff from rainfall and runoff from melting snow. The water from rainfall or melting snow flows overland until it reaches a nearby river or lake. If the river or lake cannot hold all of the water that is entering it, some of the water will begin to overflow the banks of the river or lake, causing flooding. The size of the flood is commonly influenced by such factors as the intensity of the rainfall, length of the rainfall, melting rate of the snow, and the infiltration rate of the water into the ground.
In addition to climatologically reasons for flooding in South Dakota, floods can also result from the failure of dams. Dam failure can result from defective construction or a poor foundation. Many small dams in South Dakota fail because their spillway is not big enough. Often, failure occurs as a result of extremely heavy rainfall that causes a large increase in the amount of water held by the dam. This increase in water behind the dam could place more stress (pressure) on the dam than it was designed to handle, causing the dam to fail.
What Types Of Floods Occur In South Dakota?
Four types of floods can occur in South Dakota. The first type is commonly called a flash flood. A flash flood is the result of several inches or more of rain falling in a very short period of time, often tens of minutes (Ward, 1978).This high intensity rainfall is commonly caused by powerful thunderstorms that cover a small geographic area. Because so much water is falling onto the ground very rapidly, there is little time for the water to soak in, and most of the water runs off into nearby rivers or lakes. The flood that occurs as a result of this runoff happens very rapidly, hence the term "flash." This type of flood is generally very destructive, affecting a fairly small, localized area, commonly several tens of square miles or less. The flash flood often ends almost as quickly as it started. Probably the best-known flash flood in South Dakota occurred when Rapid Creek left its banks on June 9, 1972, in Rapid City. Fifteen inches of rain that fell in less than 6 hours caused the flooding. This flood was devastating both in terms of loss of human life and property damage. Two hundred thirty-eight people lost their lives in this flood and about $150 million (in 1972 dollars) of property damage occurred (FEMA, 1987).
The second type of flooding is sometimes termed the long-rain flood, and is the most common cause of major flooding (Ward, 1978).This type of flood results after several days or even weeks of fairly low-intensity rainfall over a widespread area, often hundreds of square miles. As a result, the ground becomes "water logged," and the water can no longer infiltrate into the ground; therefore, the water begins to flow toward rivers or lakes. The flooding that can result is often widespread, covering hundreds of square miles, and can last for several days or many weeks. Much of the flooding that occurred in eastern South Dakota during the summer of 1993 was this type of flooding.
The third type of flood in South Dakota is the result of melting snow in the spring. This type has characteristics that are almost a combination of the flash flood and long-rain flood. The area covered by this type of flood is generally not as large as that covered by the long-rain flood, but is typically larger than that covered by the flash flood. Generally, the flood lasts for several days, occurring when large amounts of snow melt rapidly due to warm temperatures. The flooding can be made worse if the ground remains frozen while the snow is melting; this causes all of the melt water to run off to nearby rivers and lakes rather than infiltrate into the ground.
Some of the largest floods that have occurred in South Dakota were the result of melting snow and ice. These large floods have occurred along the entire length of the Missouri River. The Great Flood of 1881 is probably the most well known of all the floods to take place in South Dakota. Ice jams on the river caused the flooding to become extremely devastating, destroying large amounts of property and causing many lives to be lost. Towns such as Yankton, Vermillion, Burbank, Meckling, and Pierre were all severely damaged by the flooding (The Great Flood, 1881).
The fourth type of flood results from the failure of dams. The four largest dams in South Dakota -- Oahe at Pierre, Big Bend at Fort Thompson, Fort Randall at Pickstown, and Gavins Point at Yankton -- are all located on the Missouri River. Large dams in the Black Hills are the Deerfield, Pactola, Sheridan and Angostura dams. If any of these large dams were to fail, flood damage could be very great. Fortunately, all of these dams are considered to be properly constructed, and have been designed to hold back very large amounts of water; therefore, they are considered to be very safe, and the likelihood of failure is extremely small. Except for these Missouri and Black Hills dams, the majority of the dams in South Dakota are very small, and if they were to fail, flooding would likely be minimal.
I. Give Russian equivalents for the following words:
A flood, occur, to flow over, low-lying areas, valley bottom, lake basin, coastal area, occur, the amount of water, to overflow the banks, climatologically causes, runoff, rainfall, the intensity of the rainfall, length of the rainfall, melting rate of the snow, the infiltration rate of the water, the failure of dam, spillway, a flash flood, rapidly, soak in, destructive, devastate, property damage, the long-rain flood, water logged, infiltrate into the ground, ground, to remain, frozen, to melt, devastating, to destroy, the likelihood of failure, extremely, the majority of the dams.
II. Continue the following statements:
1. Therefore, the water overflows… .2. The water from rainfall or melting… .3. In addition to climatologically reasons… .4. This high intensity rainfall… .5. The flash flood often ends… .6. As a result, the ground becomes "water logged"… .7. This type has characteristics that… .8. The flooding can be made worse if… .9. Some of the largest floods… .10. Fortunately, all of these dams… .III. Translate the sentences into Russian:
1. A flood occurs when water rises to flow over land that is normally dry.
2. Floods happen in low-lying areas, such as valley bottoms, lake basins, and coastal areas.
3. In South Dakota, there are two main climatologically causes of flooding: runoff from rainfall and runoff from melting snow.
4. The size of the flood is commonly influenced by such factors as the intensity of the rainfall, length of the rainfall, melting rate of the snow, and the infiltration rate of the water into the ground.
5. This increase in water behind the dam could place more stress (pressure) on the dam than it was designed to handle, causing the dam to fail.
6. A flash flood is the result of several inches or more of rain falling in a very short period of time, often tens of minutes (Ward, 1978).7. The second type of flooding is sometimes termed the long-rain flood, and is the most common cause of major flooding (Ward, 1978).8. The third type of flood in South Dakota is the result of melting snow in the spring.
9. The flooding can be made worse if the ground remains frozen while the snow is melting; this causes all of the melt water to run off to nearby rivers and lakes rather than infiltrate into the ground.
10. Ice jams on the river caused the flooding to become extremely devastating, destroying large amounts of property and causing many lives to be lost.
IV. What type of flood is it :1. This type of flood results after several days or even weeks of fairly low-intensity rainfall over a widespread area, often hundreds of square miles.
2. This type has characteristics that are almost a combination of the flash flood and long-rain flood.
3. This type of flood is the result of several inches or more of rain falling in a very short period of time, often tens of minutes.
4. These large floods have occurred along the entire length of the Missouri River. The Great Flood of 1881 is probably the most well known of all the floods to take place in South Dakota.
V. Make a summery of the text.