Dirty River but Clean Water IELTS Reading Passage with Answers
Reading Passage 1
You should spend about 20 minutes on Questions 1-13 which are based on Reading Passage 1 below.
Real IELTS Exam Question, Reported On:
| India | 19th March 2022 |
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 brush 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
This lack of flooding has harmed local wildlife. The humpback chub, for example, thrived in the rust-red waters of 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. 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, Colorado’s rusty sediment. The chub were well adapted to the poor visibility created by the chick, 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 roundtail 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 moved in.
F
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 floodwaters built up sandbanks and infused the river with sediment. Eventually, however, the continued flow washed most of the sediment out of the canyon. 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 1?
In boxes 1-7 on your answer sheet, write
TRUEÂ Â Â Â Â Â Â Â if the statement is true
FALSEÂ Â Â Â Â Â Â if the statement is false
NOT GIVENÂ Â if the information is not given in the passage
1 Damage caused by a fire is worse than that caused by the flood.
2 The flood peaks at almost 1500 cubic meters every eight years.
3 Contribution of sediments delivered by tributaries has little impact.
4 The decreasing number of chubs is always caused by introducing of trout since the mid 20th century.
5 It seemed that the artificial flood in 1996 had achieved success partly at the very beginning.
6 In fact, the yield of artificial flood water is smaller than an average natural flood at present.
7 Mighty floods drove fast-moving flows with clean and high-quality water.
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, the canyon was raged by flood every year. The snow from far Wyoming would melt in the season of 8____________. 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____________ together from tiny, undammed tributaries.
humpback chub population reduced, why?
Then several species disappeared including Colorado pike-minnow, 10____________ and the round-tail chub. Meanwhile, some moved in such as fathead minnows, channel catfish and 11____________ The non-stopped flow led to the washing away of the sediment out of the canyon, which poses a great threat to the chubs because it has poor 12____________. away from predators. In addition, the volume of 13____________ available behind the dam was too low to rebuild the bars and flooding became more serious.
Dirty River but Clean Water IELTS Reading Answers
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1. NOT GIVEN
2. FALSE
3. NOT GIVEN
4. FALSE
5. TRUE
6. TRUE
7. NOT GIVEN
8. spring
9. sediment
10. razorback sucker
11. common carp
12. visibility
13. sand
Dirty River but Clean Water IELTS Reading Answers Explanation
1. Damage caused by the fire is worse than that caused by the flood.
Answer: Not Given
2. The flood peaks at almost 1500 cubic meters every eight years.
Answer: False
Explanation: The floods have raged through the canyon almost every year. The floods used to peak at 1500 cubic meters a second. However, in the last eight years, the floods have seen a rise of 3000 cubic meters. Therefore, the statement does not give the correct information. 1500 is the average and in last 8 years, the figure rose to 3000 cubic meters.
Supporting sentence: 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.
Keywords: Every eight years, almost 3,000 cubic metres
Location: Paragraph C
3. Contribution of sediments delivered by tributaries has little impact.
Answer: True
Explanation: The contribution of sediments does not do much for the tributaries because those tributaries are not powerful enough to distribute the sediment in an ecologically valuable way by themselves. These sediments are collected from tiny, undammed tributaries. However, the contribution of these sediments is not that significant here.
Supporting Sentence: 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.
Keywords: Sediment that it has collected has come from tiny, undammed tributaries, not been much use
Location: Paragraph D
4. The decreasing number of chubs is always caused by introducing of trout since the mid 20th century.
Answer: False
Explanation: United States’ Geological Survey’s (USGS) Steve Gloss, regards the chub’s decline due to the loss of their most valuable natural defense, 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. It was earlier believed that the chub were being eaten by trout introduced for sport fishing in the mid-20th century.
Supporting Sentence: 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 defence, 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.
Keywords: created by the thick, red water
Location: Paragraph E
5. It seemed that the artificial flood in 1996 had achieved success partly at the very beginning.
Answer: True
Explanation: In 1996 and 2004, artificial floods were set up for the Grand Canyon and that seemed pretty successful in the start. So, 1996 was the beginning of this, and 2004 was the second time of the artificial flood. The flood of 1996 went longer and the flood water made the sandbanks. It brought a lot of sediment too, to infuse the river. So, this statement is true regarding the information of the passage.
Supporting Sentence: 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 floodwaters built up sandbanks and infused the river with sediment. Eventually, however, the continued flow washed most of the sediment out of the canyon. 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.
Keywords: 1996 the flood, go on too long
Location: Paragraph G
6. In fact, the yield of artificial flood water is smaller than an average natural flood at present.
Answer: True
Explanation: The flood had a yield even smaller than an average spring flood. According to the last paragraph of the passage, it is quite clear that artificial flood water is smaller compared to the natural floodwater of the present time. Artificial flood water was 1,200 cubic meters a second and it is less than the average spring flood. As this statement agrees with the information of the reading passage, the answer is true.
Supporting Sentence: 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.
Keywords: flood is smaller, average spring flood,
Location: Paragraph H
7. Mighty floods drove fast-moving flows with clean and high-quality water.
Answer: Not given
8.
Answer: Spring
Explanation: This paragraph is about the impacts of the canyon dam and gap number 8 asks the season of the flood. According to the passage, spring snow arrived from Wyoming and swell Colorado. Paragraph C is all about the eco impacts of the canyon dam. It is clearly mentioned in the paragraph that floods once raged through the canyon every year. So, this is something common and the snow of winter gets melted during sprong which is a cause behind this.
Supporting Sentence: 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.
Keywords: Spring Snow, far away, Wyoming, melt and swell, Colorado river, flow
Location: Paragraph C
9.
Answer: Sediment
Explanation: This is also about the eco-impacts of the flood. This question asks the elements gathered during the flood. The reading passage describes the nature of the flood specifically. In the 4th paragraph of the reading passage, the elements brought by the flood are mentioned. The sediment collected in Glen Canyon dam has gathered from tiny, undammed tributaries. It is mainly the sediments that brought together with the floodwater.
Supporting Sentence: 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.
Keywords: the only sediment that it has collected has come from tiny, undammed tributaries
Location: Paragraph D
10.
Answer: Razorback sucker
Explanation: This question is about the reasons behind the Humpback chub population on reduced. It is mentioned that several species disappeared including the Colorado pike-minnow. The first blank of this summary asks about the characteristics of the chub. In the passage, this is clearly given. Since the Glen Canyon was constructed, many species vanished one of them is the razorback sucker.
Supporting Sentence: 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.
Keywords: Colorado pike-minnow, the razorback sucker and the round-tail chub
Location: Paragraph F
11.
Answer: Common Carp
Explanation: This question is also about the reasons behind the Humpback chub population on reduced. In paragraph F, the reasons are mentioned in detail. Common carp moved in place of the other fishes. fathead minnows, channel catfish, and common carps are mentioned in the passage. That’s why these are the best suitable words for the blank given.
Supporting Sentence: 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.
Keywords: aliens including fathead minnows, channel catfish and common carp
Location: Paragraph F
12.
Answer: Visibility
Explanation: The non-stopped flow led to the washing away of the sediment out of the canyon, which poses a great threat to the chubs because it has poor visibility away from predators. The chubs were used to the poor visibility of the sediments. 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.
Supporting Sentence: 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.
Keywords: poor visibility, thick, red water, vulnerable
Location: Paragraph E
13.
Answer: Sand
Explanation: As the question asks to point out the reason behind the reduction of the chub population, multiple factors can be mentioned here. The volume of sand available behind the dam was too low to rebuild the bars and flooding became more serious. As a result, rebuilding was not possible. It is directly related to the decay of the chub population.
Supporting Sentence: Eventually, however, the continued flow washed most of the sediment out of the canyon. 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.
Keywords: volume of sand available, too low
Location: Paragraph G
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