IELTS READING : Dirty River But Clean Water

PASSAGE TITLE: Dirty River But Clean Water Floods can occur in rivers when the flow rate exceeds the capacity of the river channel, particularly at bends or meanders in the waterway. Floods often cause damage to homes and businesses if they are in the natural flood plains of rivers. While riverine flood damage can be eliminated by moving away from rivers and other bodies of water, people have traditionally lived and worked by rivers because the land is usually flat and fertile and because rivers provide easy travel and access to commerce and industry.

A Fire and flood are two of humanity’s worst nightmares. People have,therefore,always sought to control them. Forest fires are snuffed out quickly. The flow of rivers is regulated by weirs and dams. At least, that is how it used to be. But foresters have learned that forests need fires to clear out the brash and even to get seeds to germinate. And a similar revelation is now – dawning on hydrologists. Rivers – and the ecosystems they support – need floods. That is why a man-made torrent has been surging down the Grand Canyon. By Thursday March 6th it was running at full throttle, which was expected to be sustained for 60 hours.

B Floods once raged through the canyon every year. Spring Snow from as far away as Wyoming would melt and swell the Colorado river to a flow that averaged around 1,500 cubic metres (50,000 cubic feet) a second. Every eight years or so, that figure rose to almost 3,000 cubic metres. These floods infused the river with sediment, carved its beaches and built its sandbars.

C However, in the four decades since the building of the Glen Canyon dam, just upstream of the Grand Canyon, the only sediment that it has collected has come from tiny, undammed tributaries. Even that has not been much use as those tributaries are not powerful enough to distribute the sediment in an ecologically valuable way.

D. 1-This lack of flooding has harmed local wildlife. The humpback chub,for example, thrived in the rust-redwaters of the Colorado. Recently, though, its population has crashed. At first sight, it looked as if the reason was that the chub were being eaten by trout introduced for sport fishing in the mid-20th century. But trout and chub co-existed until the Glen Canyon dam was built, so something else is going on. 2- Steve Gloss, of the United States’ Geological Survey (USGS), reckons that the chub’s decline is the result of their losing their most valuable natural defense, the Colorado’s rusty sediment. The chub were well adapted to the poor visibility created by the thick, red water which gave the river its name, and depended on it to hide from predators. Without the cloudy water the chub became vulnerable.

E And the chub are not alone. In the years since the Glen Canyon dam was built, several species have vanished altogether. These include the Colorado pike-minnow, the razorback sucker and the round-tail chub. Meanwhile, aliens including fathead minnows, channel catfish and common carp, which would have been hard, put to survive in the savage waters of the undammed canyon, have move din.

F. 1- So flooding is the obvious answer. Unfortunately, it is easier said than done. Floods were sent down the Grand Canyon in 1996 and 2004 and the results were mixed. In 1996 the flood was allowed to go on too long. To start with,all seemed well. The built up sandbanks and infused the river with sediment. Eventually, however, the continued flow washed most of the sediment out of the canyon. 2- This problem was avoided in 2004, but unfortunately, on that occasion, the volume of sand available behind the dam was too low to rebuild the sandbanks. This time, the USGS is convinced that things will be better. The amount of sediment available is three times greater than it was in 2004. So if a flood is going to do some good, this is the time to unleash one.

G Even so, it may turn out to be an empty gesture. At less than 1,200 cubic metres a second,this flood is smaller than even an average spring flood, let alone one of the mightier deluges of the past. Those glorious inundations moved massive quantities of sediment through the Grand Canyon,wiping the slate dirty, and making a muddy mess of silt and muck that would make modern river rafters cringe.

Questions 1-7 Do the following statements agree with the information given in Reading Passage? In boxes 1-7 on your answer sheet, write TRUE if the statement agrees with the information FALSE if the statement contradicts the information NOT GIVEN if there is no information on this 1 Damage caused by fire is worse than that caused by flood. Answer: NOT GIVEN 2 The flood peaks at almost 1500 cubic meters every eight years. Answer: FALSE 3 Contribution of sediments delivered by tributaries has little impact. Answer: TRUE 4 Decreasing number of chubs is always caused by introducing of trout since mid 20th century. Answer: FALSE 5 It seemed that the artificial flood in 1996 had achieved success partly at the very beginning. Answer: TRUE 6 In fact, the yield of artificial flood water is smaller than an average natural flood at present. Answer: TRUE 7 Mighty floods drove fast moving flows with clean and high quality water. Answer: NOT GIVEN

Questions 8-13 Complete the summary below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 8-13 on your answer sheet. The eco-impact of the Canyon Dam Floods are people’s nightmare. In the past, canyon was raged by flood every year. The snow from far Wyoming would melt in the season of 8 Answer: spring and caused a flood flow peak in Colorado river. In the four decades after people built the Glen Canyon dam, it only could gather 9 Answer: sediment together from tiny, undammed tributaries. Humpback chub population on reduced, why? Then, several species disappeared including Colorado pike-minnow, 10 Answer: razorback sucker and the round-tail chub. Meanwhile, some moved in such as fathead minnows, channel catfish and 11 Answer: common carp . The non-stopped flow leaded to the washing away of the sediment out of the canyon, which poses great threat to the chubs because it has poor 12 Answer: visibility away from predators. In addition, the volume of 13 Answer: sand available behind the dam was too low to rebuild the bars and flooding became more serious.

PASSAGE TITLE: Global Warming A- Day after day we hear about how anthropogenic development is causing global warming. According to an increasingly vocal minority, however, we should be asking ourselves how much of this is media hype cud how much is based on real evidence. It seems, as so often is the ease, that it depends on which expert you listen to, or which statistics you study. B- Yes, It is true that there is a mass of evidence to indicate that the world is getting wanner, with one of the world’s leading weather predictors stating that air temperatures have frown an increase of just under half a degree Celsius since the beginning of the twentieth century. And while this may not sound like anything worth losing sleep over, the interna­tional press would have us believe that the consequences could be devastating. C- Other ex­perts, however, are of the opinion that what we are seeing is just part of a natural upward and downward swing flint has always been part of the cycle of global weather. An analysis of the views of major meteorologists in the United States showed that less than 20% of them believed that any change in temperature over the lust hundred years was our own fault – the rest attributed it to natural cyclical changes. D- There is, of course, no denying that we are still at a very early stage in understanding weather. The effects of such variables as rainfall, cloud formation, the seas and oceans, gases such as methane and ozone, or even solar energy are still not really understood, and therefore the predictions that we make using them cannot always be relied on. E- Dr. James Hansen, in 19BH, was predicting that the likely effects of global warming would be a raising of world temperature which would have disastrous consequences for mankind: “a strong cause arid effect relationship between the current climate and human alteration of the at­mosphere”. He has now gone on record as stating that using artificial models of climate as a way of predicting change is all but impossible. In fact, he now believes that, rather than getting hotter, our planet is getting greener as a result of the carbon dioxide increase, with the prospect of increasing vegetation In areas which in recent history have been frozen wastelands. F- In fact, there is some evidence to suggest that as our computer-based weather models have become more sophisticated, the predicted rises In temperature have been cut back. In addi­tion, if we Look at the much reported rise in global temperature over the last century, a close analysis reveals that the lion’s share of that increase, almost three quarters in total, occurred before man began to “poison” his world with industrial processes anti the accom­panying greenhouse gas emissions in the second half of the twentieth century. G- So should we pay any attention to those stories that scream out at us from billboards and television news headlines, claiming that man, with his inexhaustible dependence on oil-based machinery and ever more sophisticated forms of transport is creating a nightmare level of greenhouse gas emissions, poisoning his environment and ripping open the ozone layer? Doubters point to scientific evidence, which can prove that, of all the greenhouse gases, only two percent come From man-made sources, the rest resulting from natural emissions. H- Who, then, to believe: the environmentalist exhorting us to leave the car at home, to buy re-usable products packaged in recycled paper and to plant trees in our back yard? Or the sceptics, including, of course, a lot of big businesses who have most to lose, when they tell us that we are making a mountain out of a molehill? And my own opinion? The jury’s still out as for as I am concerned! -----END

Questions 1-5 1) The author … A believes that man is causing global warming B believes that global warming is a natural process C is sure what the causes of global warming are D does not say what he believes the causes of global warming are Answer: D 2) As to the cause of global warming, the author believes that … A occasionally the fact depend on who you are talking to B the facts always depend on who you are talking to C often the fact depend on which expert you listen to D you should not speak to experts Answer: C 3) More than 80% of the top meteorologists in the United States are of the opinion that.. . A global warming should make us lose sleep B global warming is not the result oil natural cyclical changes, but man-made C the consequences of global warming will be deviating D global warming is not man-made, but the result of natural cyclical changes Answer: D 4) Our understanding of weather… A leads to reliable predictions B Is variable C cannot be denied D is not very developed yet Answer: D 5) Currently, Dr. James Hansen’s beliefs include the fact that … A It is nearly Impossible to predict weather change using artificial models B the consequences of global warming would be disastrous for in mankind C there Is a significant link between the climate now, mid man’s changing of the atmosphere D Earth is getting colder Answer: A

Questions 6-11 Do the statements below agree with the information in Reading Passage? In Boxes 6-11, write: Yes if the statement agrees with the information in the passage No if the statement contradicts the information in the passage Not Given if there ls no information about the statement in the passage Example: Computer-based weather models have become more sophisticated. Answer: Yes. 6 At the same time that computer-based weather models have become more sophisticated, weather forecasters have become more expert. Answer: NOT GIVEN 7 Most of the increase In global temperature happened in the second half of the twentieth century. Answer: NO 8 The media wants us to blame ourselves for global warming. Answer: YES 9 The media encourages the public to use environmentally friendly vehicles, such as electric cars to combat global warming. Answer: NOT GIVEN 10 Environmentalists are very effective at persuading people to be kind to the environment. Answer: NOT GIVEN 11 Many big businesses are on the side of the skeptics as regards the cause of global warming. Answer: YES

Questions 12 and 13 Complete the sentences below. Use NO MORE THAN THREE WORDS from the passage for each blank space. Write your answers in Boxes 12 and 13 on your answer sheet. 12) As well as planting trees and not driving, the environmentalist would like us to choose products that are wrapped 12 Answer: in recycled paper and can be used more than once. 13) Big businesses would have us believe that we are making too much fuss about global warming, because they have 13 Answer: most to lose

Question 14 Choose the appropriate letter A-D and write it in Box 14 on your answer sheet 14) Which of these is the best title for this text? A Global Warming is for real B Global warming – media hype or a genuine threat? C Weather changes over the last 100 years D Global Warming – the greatest threat to mankind Answer: B