VOA慢速英语--秘鲁古老的供水系统可以解决缺水问题

Ancient Water System in Peru Could Fix Water Shortages

Sometimes modern problems require ancient solutions.

A 1,400-year-old Peruvian method of diverting water could supply up to 40,000 Olympic-size swimming pools' worth of water to Lima each year. That information comes from a new study published in Nature Sustainability.

It's one example of how ancient methods could support existing modern ones in countries without enough water.

More than a billion people across the world face water shortages. Man-made reservoirs store rainwater and water overflow¹ for use during drier times. But reservoirs are costly², require years to plan and can still fail to meet water needs. Recently, for example, the reservoirs in Chennai, India, went almost dry. The city’s four million people had to then depend on water transports from the government.

Peru's capital, Lima, depends on water from rivers high in the Andes Mountains. It takes only a few days for water to flow down to the city. So when the dry season begins in the mountains, the water supply quickly disappears. The city suffers shortages of 43 million cubic meters during the dry season. It resolves this with modern structures such as man-made reservoirs.

These reservoirs are not the only solution, however. Over a thousand years ago, indigenous³ people developed another way to solve water problems.

Boris Ochoa-Tocachi is a researcher at Imperial College London and lead writer of the study. He explored one of the last remaining water-harvesting systems in the small mountain community of Huamantanga, Peru. The system was developed even before the ancient Inca civilization.

Water diverted, delayed

The 1,400-year-old system is designed to increase the water supply during the dry season by diverting and slowing water as it travels down the mountains.

This nature-based method is made of special canals that guide water from its source to a series of water bodies and hillsides. The water goes slowly into the ground, then flows downhill through the soil and reappears in water bodies near the community.

Its aim was to increase the water's travel time from days to months in order to provide water throughout the dry season.

But Ochoa-Tocachi said the amount of water that could be harvested was an unknown before the study.

The researchers measured how much the system slowed the flow of water by injecting special dye in the highlands and noting when it reappeared in water bodies. The dyed water started to surface two weeks later and continued flowing for eight months — a huge improvement over the hours or days it would normally take.

"I think probably the most exciting result is that we actually confirmed that this system works," Ochoa-Tocachi said. "It's not only trusting that, yeah, we know there are traditional practices, we know that indigenous knowledge is very useful.” He said there is now proof the systems are valuable today and can be a tool to help solve modern problems.

Sizable increase in supply

The researchers next considered how using a larger version of the system could help Lima. They combined what they learned in Huamantanga with the knowledge of physical qualities of Lima's surroundings. The resulting estimates say the system could increase Lima's dry-season water supply by 7.5 percent overall and up to 33 percent at the start of the dry season. This amounts to nearly 100 million cubic meters of water each year — equal to 40,000 Olympic-size swimming pools.

Todd Gartner is director of the Natural Infrastructure⁵ Initiative at the World Resources Institute. He noted⁶ that this study "takes what we often just talk about…and it puts this into practice.” He said it does a lot of evaluation⁷ and observation and “puts real numbers behind it.”

The system is also economically sound. Ochoa-Tocachi estimated that building canals similar to those in Huamantanga would cost 10 times less than building a reservoir of the same size. He also said former highland⁴ societies in other parts of the world had methods for diverting and slowing water flow. And, they could use these methods today to support their costlier⁸ modern methods.

"I think there is a lot of potential in revaluing these water-harvesting practices that have a very long history," Ochoa-Tocachi said. He added that the idea of “using indigenous knowledge for solving modern engineering problems…is probably very valuable today."

I’m Alice Bryant. And I'm Caty Weaver⁹.

Words in This Story

divert – v. to change the direction or use of something

reservoir – n. a usually man-made lake used to store water for use in people's homes, businesses and other places

indigenous – adj. describing ethnic¹⁰ groups who are the original settlers to a specific region

canal – n. a long narrow place that is filled with water and was created by people

dye – n. a substance used for changing the color of something

actually – adv. used to refer to something that is true or real

evaluation – n. o judge the value or condition of (someone or something) in a careful and thoughtful way

potential – n. a quality that something has that can be developed to make it better

1 overflow   

v.(使)外溢，(使)溢出；溢出，流出，漫出

参考例句：

• The overflow from the bath ran on to the floor.浴缸里的水溢到了地板上。
• After a long period of rain,the river may overflow its banks.长时间的下雨天后，河水可能溢出岸来。

2 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

3 indigenous   

adj.土产的，土生土长的，本地的

参考例句：

• Each country has its own indigenous cultural tradition.每个国家都有自己本土的文化传统。
• Indians were the indigenous inhabitants of America.印第安人是美洲的土著居民。

4 highland   

n.(pl.)高地，山地

参考例句：

• The highland game is part of Scotland's cultural heritage.苏格兰高地游戏是苏格兰文化遗产的一部分。
• The highland forests where few hunters venture have long been the bear's sanctuary.这片只有少数猎人涉险的高山森林，一直都是黑熊的避难所。

5 infrastructure   

n.下部构造，下部组织，基础结构，基础设施

参考例句：

• We should step up the development of infrastructure for research.加强科学基础设施建设。
• We should strengthen cultural infrastructure and boost various types of popular culture.加强文化基础设施建设，发展各类群众文化。

6 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

7 evaluation   

n.估价，评价；赋值

参考例句：

• I attempted an honest evaluation of my own life.我试图如实地评价我自己的一生。
• The new scheme is still under evaluation.新方案还在评估阶段。

8 costlier   

adj.昂贵的( costly的比较级 )；代价高的；引起困难的；造成损失的

参考例句：

• Alligator skin is five times more costlier than leather. 鳄鱼皮比通常的皮革要贵5倍。 来自互联网
• Disagreements among creditors can be costlier still. 债权人之间的分歧会加大重组的费用。 来自互联网

9 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。

10 ethnic   

adj.人种的，种族的，异教徒的

参考例句：

• This music would sound more ethnic if you played it in steel drums.如果你用钢鼓演奏，这首乐曲将更具民族特色。
• The plan is likely only to aggravate ethnic frictions.这一方案很有可能只会加剧种族冲突。