劍橋雅思5 Test 3閱讀Passage 2原文翻譯Disappearing Delta

劍橋雅思5 Test 3閱讀Passage 2原文翻譯Disappearing Delta，今天中國教育在線就來為大家分析這個(gè)問題。

Disappearing Delta

消失的三角洲

劍橋雅思5 Test 3 Passage 2閱讀原文翻譯

A部分

The fertile land of the Nile delta is being eroded along Egypt’s Mediterranean coast at an astounding rate,in some parts estimated at 100 metres per year.In the past,land scoured away from the coastline by the currents of the Mediterranean Sea used to be replaced by sediment brought down to the delta by the River Nile,but this is no longer happening.

埃及地中海沿岸尼羅河三角洲的肥沃土地正以驚人的速度被侵蝕。在某些地方，估計(jì)達(dá)到100米/每年。過去，被地中海水洋流沖刷掉的海岸線的土地會被尼羅河（River Nile）帶到三角洲的沉積物所代替，但是這種情況已經(jīng)不再發(fā)生。

B部分

Up to now,people have blamed this loss of delta land on the two large dams at Aswan in the south of Egypt,which hold back virtually all of the sediment that used to flow down the river.Before the dams were built,the Nile flowed freely,carrying huge quantities of sediment north from Africa’s interior to be deposited on the Nile delta.This continued for 7,000 years,eventually covering a region of over 22,000 square kilometres with layers of fertile silt.Annual flooding brought in new,nutrient-rich soil to the delta region,replacing what had been washed away by the sea,and dispensing with the need for fertilizers in Egypt’s richest food-growing area.But when the Aswan dams were constructed in the 20th century to provide electricity and irrigation,and to protect the huge population centre of Cairo and its surrounding areas from annual flooding and drought,most of the sediment with its natural fertilizer accumulated up above the dam in the southern,upstream half of Lake Nasser,instead of passing down to the delta.

迄今為止，人們將三角洲土壤流失的責(zé)任歸咎于埃及南部阿斯旺的兩座大水壩。這些水壩文章來自 雅思實(shí)際上攔截了過去順流而下的所有沉積物。在修建大壩之前，尼羅河自由流動，將非洲內(nèi)陸大量的沉積物向北帶到尼羅河三角洲。這種情況持續(xù)了7,000年，最終形成22,000平方公里的肥沃土壤。每年的洪水給三角洲地區(qū)帶來了營養(yǎng)豐富的新土壤，代替被海水沖走的那些，并滿足埃及最富有的糧食種植區(qū)對肥料的需求。但是，當(dāng)阿斯旺大壩在20世紀(jì)被建造起來以提供電力和灌溉，并保護(hù)開羅及其周邊地區(qū)的巨大人口中心免受年度洪水和干旱的侵襲時(shí)，大部分的沉積物及其天然肥料都堆積在大壩南部上方，納賽爾湖上游的一半，而不是向下到三角洲。

C部分

Now,however,there turns out to be more to the story.It appears that the sediment-free water emerging from the Aswan dams picks up silt and sand as it erodes the river bed and banks on the 800-kilometre trip to Cairo.Daniel Jean Stanley of the Smithsonian Institute noticed that water samples taken in Cairo,just before the river enters the delta,indicated that the river sometimes carries more than 850 grams of sediment per cubic metre of water–almost half of what it carried before the dams were built.‘I’m ashamed to say that the significance of this didn’t strike me until after I had read 50 or 60 studies,’says Stanley in Marine Geology.‘There is still a lot of sediment coming into the delta,but virtually no sediment comes out into the Mediterranean to replenish the coastline.So this sediment must be trapped on the delta itself.’

但是，現(xiàn)在，事實(shí)證明故事還不止于此。從阿斯旺水壩涌出的不含沉積物水在前往開羅的800公里的行程中，沖走了淤泥和沙子，侵蝕了河床和河岸。史密森尼學(xué)會（Smithsonian Institute）的丹尼爾·讓·斯坦利（Daniel Jean Stanley）注意到，在河流進(jìn)入三角洲之前，在開羅采集的水樣表明，河流每立方米水中有時(shí)攜帶850克以上的沉積物-幾乎是大壩修建之前沉積量的一半?！拔倚哂诔姓J(rèn)，直到讀了50或60篇研究之后才意識到這一發(fā)現(xiàn)的重要性”，斯坦利在Marin Geology上說，“仍有大量沉積物進(jìn)入三角洲，但實(shí)際上沒有沉積物進(jìn)入地中海以補(bǔ)充海岸線。因此，這些沉積物一定被困在了三角洲自己身上”。

D部分

Once north of Cairo,most of the Nile water is diverted into more than 10,000 kilometres of irrigation canals and only a small proportion reaches the sea directly through the rivers in the delta.The water in the irrigation canals is still or very slow-moving and thus cannot carry sediment,Stanley explains.The sediment sinks to the bottom of the canals and then is added to fields by farmers or pumped with the water into the four large freshwater lagoons that are located near the outer edges of the delta.So very little of it actually reaches the coastline to replace what is being washed away by the Mediterranean currents.

開羅以北，尼羅河的大部分水被引到10,000多公里的灌溉渠中，只有一小部分直接通過三角洲的河流到達(dá)大海。斯坦利解釋說，灌溉渠中的水要么靜止要么流動非常緩慢，因此無法攜帶沉積物。沉積物沉入運(yùn)河底部，然后由農(nóng)民加到田間，或與水一起泵入位于三角洲外緣的四個(gè)大型淡水瀉湖中。因此實(shí)際上只有很少部分到達(dá)海岸線來代替被地中海洋流沖走的東西。

E部分

The farms on the delta plains and fishing and aquaculture in the lagoons account for much of Egypt’s food supply.But by the time the sediment has come to rest in the fields and lagoons it is laden with municipal,industrial and agricultural waste from the Cairo region,which is home to more than 40 million people.‘Pollutants are building up faster and faster,’says Stanley.

三角洲平原上的農(nóng)場以及瀉湖中的漁業(yè)和水產(chǎn)養(yǎng)殖業(yè)占埃及糧食供應(yīng)的大部分。但是，當(dāng)沉積物在田野和瀉湖中沉淀下來時(shí)，它已經(jīng)充滿了來自開羅地區(qū)市政，工業(yè)和農(nóng)業(yè)的廢物。該地區(qū)居住著4000萬人。斯坦利說：“污染物的積累越來越快?！?/p>

Based on his investigations of sediment from the delta lagoons,Frederic Siegel of George Washington University concurs.‘In Manzalah Lagoon,for example,the increase in mercury,lead,copper and zinc coincided with the building of the High Dam at Aswan,the availability of cheap electricity,and the development of major power-based industries,’he says.Since that time the concentration of mercury has increased significantly.Lead from engines that use leaded fuels and from other industrial sources has also increased dramatically.These poisons can easily enter the food chain,affecting the productivity of fishing and farming.Another problem is that agricultural wastes include fertilizers which stimulate increases in plant growth in the lagoons and upset the ecology of the area,with serious effects on the fishing industry.

根據(jù)他對三角洲瀉湖沉積物的調(diào)查，喬治華盛頓大學(xué)的弗雷德里克·西格爾（Frederic Siegel）贊同上述觀點(diǎn)?！袄?，Manzalah瀉湖中水銀，鉛，銅和鋅增長的時(shí)間恰好與阿斯旺大壩的建造，廉價(jià)電力的提供，以及主要電力基礎(chǔ)產(chǎn)業(yè)發(fā)展建設(shè)的時(shí)間相同，”他說。自那時(shí)以來，水印的濃度已大大增加。來自使用含鉛燃料的發(fā)動機(jī)和其他工業(yè)來源的鉛也急劇增加。這些有毒物質(zhì)很容易進(jìn)入食物鏈，影響漁業(yè)和農(nóng)業(yè)的生產(chǎn)力。另一個(gè)問題是，農(nóng)業(yè)廢物中包含的肥料會刺激瀉湖中植物的生長并破壞該地區(qū)的生態(tài)，對漁業(yè)產(chǎn)生嚴(yán)重影響。

F部分

According to Siegel,international environmental organisations are beginning to pay closer attention to the region,partly because of the problems of erosion and pollution of the Nile delta,but principally because they fear the impact this situation could have on the whole Mediterranean coastal ecosystem.But there are no easy solutions.In the immediate future,Stanley believes that one solution would be to make artificial floods to flush out the delta waterways,in the same way,that natural floods did before the construction of the dams.He says,however,that in the long term an alternative process such as desalination may have to be used to increase the amount of water available.‘In my view,Egypt must devise a way to have more water running through the river and the delta,’says Stanley.Easier said than done in a desert region with a rapidly growing population.

根據(jù)西格爾（Siegel）的說法，國際環(huán)境組織開始更加關(guān)注該地區(qū)。部分原因是尼羅河三角洲的侵蝕和污染問題，但主要是因?yàn)樗麄儞?dān)心這種情況可能會對整個(gè)地中海沿岸生態(tài)系統(tǒng)產(chǎn)生影響。但是沒有簡單的解決方案。斯坦利認(rèn)為，短期來看，一種解決方案將是制造人工洪水以沖刷三角洲水道，就像自然洪水在修建大壩之前做的一樣。但他說，長遠(yuǎn)來看，可能必須使用諸如海水淡化等替代工藝來增加可用水量。斯坦利說：“我認(rèn)為，埃及必須設(shè)計(jì)一種方法，使更多的水流經(jīng)河道和三角洲?！边@說起來比在人口迅速增長的沙漠地區(qū)做起來要容易。

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