VOA标准英语2009年-Satellites Predict Severe Water Shortages

New satellite data reveal that groundwater in Northwest India is being depleted¹ faster than it is being replenished³ by rainwater. Experts say the problem is being caused by farmers' excessive use of groundwater to irrigate⁴ their crops, and they warn that the situation could lead to severe water shortages and reduced agricultural yields.
　
Groundwater storage varied⁵ in NW India between 2002-2008, relative to the mean for the period. These deviations⁶ are expressed as the height of an equivalent water layer ranging from -12 cm (deep red) to 12 cm (dark blue), 12 Aug 2009

Groundwater is the main source of fresh water for drinking, washing and agriculture in many parts of the world, including India. But a new study concludes that natural underground aquifers⁸ are being drawn⁹ down by heavy irrigation demand, and that this rapid depletion¹⁰ could lead to severe, widespread water shortages for 114 million people living in the country's northwestern states of Rajasthan, Punjab and Haryana, an area that includes the country's capital, New Delhi.

Matt Rodell is a hydrologist with the U.S. space agency's Goddard Space Flight Center in Maryland. Rodell headed up the study looking at data collected by NASA's Gravity Recovery and Climate Experiment satellites, or GRACE. Orbiting the Earth in tandem¹¹, the twin satellites are able to measure and map changes in water storage on land and beneath the surface. In graphic¹² representations of water supplies around the globe, GRACE highlights areas of water depletion in red.

Rodell says researchers decided¹³ to use GRACE to take a closer look to see what was going on in northwest India where local reports said that peoples' wells were running dry.

"And one of the things that jump[s] out is this [red] bull's eye over northern India," he said.

Rodell says that using data from GRACE, scientists confirmed that the amount of rainwater soaking into underground aquifers is not enough to naturally replenish² what's being sucked out of the ground for agriculture.

He says records showed the amount of water contained in above-ground reservoirs remained the same during the six year study, ruling out the possibility that climate change was causing a reduction in rainfall.

Rodell says 95 percent of the water that's pumped out of the ground in this arid¹⁴, almost desert-like region of India is used for crop irrigation, and he says there's no doubt now that farmers in the northwest are using too much water on their fields.

"So, averaged over this three-state region, the water levels are declining in the aquifer⁷ by about one foot [third of a meter] per year. So, over this entire region, that's equivalent to a groundwater depletion of about 109 cubic kilometers over the past six years," he added.

Put another way, Rodell says, the amount of underground water depletion is about double the capacity of India's largest reservoir.
　
A farmer prepares to plant paddy seedlings¹⁵ in Phoolpur, east of Allahabad, India (File)

Rodell says the Indian government is aware of the problem and has begun drafting regulations that would limit groundwater consumption.

"Probably the best thing to do is to use that water more efficiently¹⁶. As I mentioned, planting crops that require less water and using more efficient irrigation techniques are probably the best way to do that," he said.

Rodell says researchers are also using GRACE to investigate water supply trends in other parts of the world.

The study looking at the depletion of groundwater in northwest India is published this week in the journal Nature.

1 depleted   

adj. 枯竭的, 废弃的 动词deplete的过去式和过去分词

参考例句：

• Food supplies were severely depleted. 食物供应已严重不足。
• Both teams were severely depleted by injuries. 两个队都因队员受伤而实力大减。

2 replenish   

vt.补充；(把…)装满；(再)填满

参考例句：

• I always replenish my food supply before it is depleted.我总是在我的食物吃完之前加以补充。
• We have to import an extra 4 million tons of wheat to replenish our reserves.我们不得不额外进口四百万吨小麦以补充我们的储备。

3 replenished   

补充( replenish的过去式和过去分词 )； 重新装满

参考例句：

• She replenished her wardrobe. 她添置了衣服。
• She has replenished a leather [fur] coat recently. 她最近添置了一件皮袄。

4 irrigate   

vt.灌溉，修水利，冲洗伤口，使潮湿

参考例句：

• The farmer dug several trenches to irrigate the rice fields.这个农民挖了好几条沟以灌溉稻田。
• They have built canals to irrigate the desert.他们建造成水渠以灌溉沙漠。

5 varied   

adj.多样的，多变化的

参考例句：

• The forms of art are many and varied.艺术的形式是多种多样的。
• The hotel has a varied programme of nightly entertainment.宾馆有各种晚间娱乐活动。

6 deviations   

背离，偏离( deviation的名词复数 )； 离经叛道的行为

参考例句：

• Local deviations depend strongly on the local geometry of the solid matrix. 局部偏离严格地依赖于固体矩阵的局部几何形状。
• They were a series of tactical day-to-day deviations from White House policy. 它们是一系列策略上一天天摆脱白宫政策的偏向。

7 aquifer   

n.含水土层

参考例句：

• An aquifer is a water-bearing rock stratum such as sandstone and chalk.地下蓄水层是一些有水的岩石层，如沙岩和白垩岩。
• The wine region's first water came from an ancient aquifer.用来灌溉这个地区葡萄园的第一批水来自古老的地下蓄水层。

8 aquifers   

n.地下蓄水层，砂石含水层( aquifer的名词复数 )

参考例句：

• And in Africa, the aquifers barely recharge at all. 非洲的地下水开采以后几乎得不到补充。 来自时文部分
• Aquifers have water contents over 30%. 含水层的水含过30％。 来自辞典例句

9 drawn   

v.拖，拉，拔出；adj.憔悴的，紧张的

参考例句：

• All the characters in the story are drawn from life.故事中的所有人物都取材于生活。
• Her gaze was drawn irresistibly to the scene outside.她的目光禁不住被外面的风景所吸引。

10 depletion   

n.耗尽，枯竭

参考例句：

• Increased consumption of water has led to rapid depletion of groundwater reserves.用水量的增加导致了地下水贮备迅速枯竭。
• Farmers should rotate crops every season to prevent depletion of the soil.农夫每季应该要轮耕，以免耗尽土壤。

11 tandem   

n.同时发生；配合；adv.一个跟着一个地；纵排地；adj.（两匹马）前后纵列的

参考例句：

• Malcolm's contract will run in tandem with his existing one.马尔科姆的合同将与他手头的合同同时生效。
• He is working in tandem with officials of the Serious Fraud Office.他正配合欺诈重案办公室的官员工作。

12 graphic   

adj.生动的，形象的，绘画的，文字的，图表的

参考例句：

• The book gave a graphic description of the war.这本书生动地描述了战争的情况。
• Distinguish important text items in lists with graphic icons.用图标来区分重要的文本项。

13 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

14 arid   

adj.干旱的；(土地)贫瘠的

参考例句：

• These trees will shield off arid winds and protect the fields.这些树能挡住旱风,保护农田。
• There are serious problems of land degradation in some arid zones.在一些干旱地带存在严重的土地退化问题。

15 seedlings   

n.刚出芽的幼苗( seedling的名词复数 )

参考例句：

• Ninety-five per cent of the new seedlings have survived. 新栽的树苗95%都已成活。 来自《现代汉英综合大词典》
• In such wet weather we must prevent the seedlings from rotting. 这样的阴雨天要防止烂秧。 来自《现代汉英综合大词典》

16 efficiently   

adv.高效率地，有能力地

参考例句：

• The worker oils the machine to operate it more efficiently.工人给机器上油以使机器运转更有效。
• Local authorities have to learn to allocate resources efficiently.地方政府必须学会有效地分配资源。