2009 HiMCM A题特等奖学生论文下载2358
2009 HiMCM A题特等奖学生论文下载2358
下载方式见文末
论文摘要如下：
"Water, water, everywhere, nor any drop to drink"
- Rhyme of the Ancient Mariner, by Coleridge.
Without water there would be no life on Earth. We use it to maintain our health, agriculture, industry, and economic vitality. In fact, one of the main struggles of civilizations has been harnessing fresh water resources for the public good. It is ironic that, of all the water that exists on the planet, three percent is freshwater found in ice, lakes and rivers, and underground aquifers.
In the 21st century, global water supply has become a more serious issue every day, and this is even true in developed nations like the United States, where an abundant supply of freshwater is sometimes taken for granted. In 1800, the 5.3 million citizens of the United States enjoyed virtually unlimited supplies of clean fresh water. In 2009, the growing population of over 300 million is pushing the limits of the geography’s natural resources. The U.S. currently finds itself in a state of water stress, using more fresh water than can naturally be replenished by the water, or hydrologic, cycle. This is true especially in areas that rely on groundwater found in aquifers, which accounts for 99% of all usable freshwater, but only accounts for 20% of human water withdrawals (Center for Sustainable Systems).
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