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DEVELOPMENT REPORT - Storing Drinking Water

时间:2005-09-27 16:00来源:互联网 提供网友:bcxpj17   字体: [ ]
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DEVELOPMENT REPORT

January 7, 2002: Storing Drinking Water

By Gary Garriott


This is the VOA Special English Development Report.

Safe drinking water has always been rare and valuable. Throughout the world, drinking water has to be stored for
periods of low rainfall. Tanks or other containers for water storage must be ready long before a dry season
begins.

For hundreds of years different kinds of materials have been used to build water storage containers. In many
areas of the world, small lakes or reservoirs1 formed by dirt walls provide drinking water for villagers during the
long dry season. In western Sudan, the thick part of the baobob tree is removed to store water collected during the
short rainy season in that country.

Bricks2 and concrete are among the modern materials used today to build storage containers for water. A solid
rock can be used as the bottom of a water tank. However, a mixture of rock and soil should not be used. The soil
will settle down, but the rock will not. The water will leak out.

Ferro-cement3 structures are popular in some developing countries, especially in India. Ferro -cement is made by
pouring a sand and cement mixture over a skeleton4 form made of steel rods5, pipe, or chicken wire. It creates a
structure that is lightweight yet keeps in water. The walls of ferro-cement structures are usually thin, which
means that they can be used in building different shapes such as circles.

Wood also can be used for water storage structures. Cypress6, fir, pine and redwood are some of the kinds of trees
that have been used. Wooden tanks do not require special care, although their average lifetime is shorter than
tanks made with concrete or steel. Any chemicals used to keep the wood from being ruined must not be
poisonous substances.

Water in uncovered7 storage tanks or reservoirs can become unsafe. Small green plants called algae8 can grow in
large amounts near the surface. The algae may help bacteria continue to grow, even if chemicals such as chlorine
are added to the water to kill the bacteria. Uncovered water also can be polluted by birds, animals or humans.

You can learn more about storing water for drinking through the Volunteers in Technical Assistance9, or VITA.
You can reach VITA through the Internet at its World Wide Web address w-w-w dot v-i-t-a dot o-r-g.

This VOA Special English Development Report was written by Gary Garriott.


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1 reservoirs 5f2b7d60f2d2f9ae63561eebd8a797c3     
n.水库( reservoir的名词复数 );储藏;大量的储备;储液槽
参考例句:
  • We must make use of our untapped reservoirs of talent. 我们必须利用我们尚未利用的人才。 来自《简明英汉词典》
  • The big storms in August refilled the reservoirs. 八月的暴雨又使水库积满了水。 来自《简明英汉词典》
2 bricks ecfd485b7a182bfae368098672fd35c8     
n.砖( brick的名词复数 );砖块;积木;可靠的朋友
参考例句:
  • He compounded water, sand and soil and formed bricks. 他用水拌和沙和泥土做成砖块。
  • The United Auto Workers hit the bricks against General Motors. 联合汽车工人工会举行罢工,反对通用汽车公司。
3 cement IXmzk     
n.水泥;胶结材料;vt.粘结;巩固
参考例句:
  • We need 100 tons of cement at most for this project.这项工程满打满算有一百吨水泥就足够了。
  • Let's cement the parts together.咱们来把这些部件粘接在一起吧。
4 skeleton OE7z0     
n.骨骼,框架,骨干,梗概,提要
参考例句:
  • A long illness made a skeleton out of him.长期的卧病使他骨瘦如柴。
  • Her notes gave us just the bare skeleton of her theory.她的笔记只给我们提供了她的理论的梗概。
5 rods bbd0cd8ec6e4bc51d143b2880f679e05     
竿( rod的名词复数 ); 杆; (责打人用的)棍棒; 手枪
参考例句:
  • The wheels of the toy car were fixed on metal rods. 玩具车的轮子固定在金属棒上。
  • A typewriter in which the characters are situated on type rods. 一种打字机,其字符安装在字模棒上。
6 cypress uyDx3     
n.柏树
参考例句:
  • The towering pine and cypress trees defy frost and snow.松柏参天傲霜雪。
  • The pine and the cypress remain green all the year round.苍松翠柏,常绿不凋。
7 uncovered 5fszak     
adj.无盖的,未保险的v.揭开…的盖子( uncover的过去式和过去分词 );揭露,发现
参考例句:
  • His head was uncovered. 他光着头。
  • A plot to assassinate the banker has been uncovered by the police. 暗杀银行家的密谋被警方侦破了。 来自《简明英汉词典》
8 algae tK6yW     
n.水藻,海藻
参考例句:
  • Most algae live in water.多数藻类生长在水中。
  • Algae grow and spread quickly in the lake.湖中水藻滋蔓。
9 assistance CO8yr     
n.援助,帮助
参考例句:
  • She called and called but no one came to her assistance.她叫了又叫,但没有人来帮。
  • He will get the great possible assistance.他将获得尽可能大的帮助。
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