Sinking Cities - IELTS Reading Answers & Explanations
From Collins Practice Tests For IELTS 1 Academic Reading Test 4 · Part 3 · Questions 28–40
Reading Passage
You should spend about 20 minutes on Questions 28-40, which are based on Reading Passage 3 below.
Sinking Cities
Looking across the Bund towards Pudong across the Huangpu River in Shanghai, you will see an array of modern world-beating skyscrapers. In contrast, behind you are the magnificent buildings from the nineteenth century. Standing on the high tourist promenade that runs the length of the waterfront, you may also notice that the level of the river is quite a bit higher than that of the buildings on the Bund. It isn't because the river has risen higher than usual due to rainfall; no - Shanghai is sinking. It is an unfortunate problem that Shanghai shares with several other major financial and industrial centres and it is caused by factors most of the cities have in common. Included in the list are New York, Bangkok, Houston and Mexico City, all either built on shaky foundations or low-lying land that is now threatened by rising sea levels.
New York and Bangkok are victims of bad luck. The effect of global warming on the sea levels means that these cities may drown in the oceans that brought them such importance and prosperity. Scientists believe that sea levels in the New York area are expected to rise about twice as quickly as in the rest of the world. The position of the city - situated where the Hudson River flows into the Atlantic Ocean - already puts America's most densely populated city at a higher risk of flooding. But the impact of tropical storms and rising tides poses more dangers than just flooding. Beaches in the area will be swept away followed by the surrounding wetlands eventually becoming part of the sea; surrounding river estuaries will see an increase in the salt levels in the fresh water. All of this will affect the ecosystems in New York's immediate area and damage developments along the coast. Bangkok too will fall victim to rising sea levels. Also situated on swamplands next to a river, the Chao Phraya, the city is about 50 kilometres north of the Gulf of Thailand. The city is likely to face increasingly severe tropical storms crossing from the Bay as well as threats from coastal erosion and shifting clay soil. It seems unlikely that Bangkok will save itself from drowning under the waters of the Pacific, which are predicted to rise by between 19 and 29 cm by 2050.
Other cities are sinking due to bad planning rather than bad luck. The fourth largest city in America is Houston but it has been built on shaky foundations - and these are now giving way. Houston was literally built on a foundation of sand up to several kilometres deep and loosely packed clay from river deposits formed from the erosion of the Rocky Mountains. In addition to poor foundation materials, Houston has an estimated 300 fault lines running through it. Using GPS data from 24 measuring points throughout the country between 1995 to 2005 a research team were able to monitor the area of subsidence and found an area of Houston measuring 30 kilometres squared was sinking very fast - up to 5 centimetres per year. The reason for the subsidence is quite straightforward: the withdrawal of water from deep beneath the surface. Areas of Houston where water extraction has been stopped have stopped sinking. Similarly, parts of Mexico City are subsiding rapidly due to poor foundations - some areas of the city are sinking up to 20 centimetres a year. The city is built on a dry lake bed in the valley of Mexico, and the council has condemned fifty structures since 2006 because of leaning, and approximately 5,000 homes and buildings are unstable. Some of the heaviest buildings, like the Palace of Fine Arts, have sunk more than three metres over the past one hundred years and its original ground floor is now the basement. Again the reason is the depletion of the water reserve lying under the city. But in this case there is a complicating factor: a vast complex of drains was built under the city to protect it from flooding by water running from the surrounding mountains. As the city sinks, so do the drains and the wastewater they were supposed to carry away is finding its way back to the city. And it's not only water mains and drains that have been affected; as the city sinks the subway network is subsiding with it.
Back in Shanghai, the same problem is causing the city of 13 million people and ultra-modern skyline to sink beneath the waterline of the Huang Pu River. Originally a small fishing village built on swamplands surrounding the mouth of the Yangtze River, Shanghai's population has swollen to around 13 million people. The expansion has been sustained by taking water from wells drilled into the aquifer under the city and by constructing massive skyscrapers. According to China Central Television, Shanghai has sunk up to three metres since the early 1990s mainly due to depletion of underground water but also because of the weight of high-rise buildings situated on areas with soft soil. As a partial solution to the problem, Shanghai is trying to reverse the sinking by pumping 5.2 billion gallons of water a year into the water table with some success - so far the city has risen by almost 11.5 cm.
Questions
Questions 28–35 Table Completion
Complete the table below.
Choose NO MORE THAN THREE WORDS from the passage for each answer.
| City | Situated | Cause of sinking | Effect |
|---|---|---|---|
| New York | where the Hudson meets the Atlantic | the effect of 28 and rising tides | increased chance of 29 |
| Bangkok | on swamps near the Gulf of Thailand | increasingly damaging storms, 30 and moving soil | a rise in the level of the Pacific of up to 31 by 2050 |
| Mexico City | on a 32 that has dried out | using up the 33 beneath the city | wastewater drains and subway affected |
| Shanghai | on wetlands around the 34 of the Yangtze River | wells drilled into aquifer and building 35 | sunk up to 3 metres |
Questions 36–40 Multiple Choice (One Answer)
Choose the correct letter, A, B, C or D.
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q28 | tropical storms / storms | But the impact of tropical storms and rising tides poses more dangers than just flooding | Excerpt/Passage Explanation: The passage explains that both the powerful storms and the moving sea water from the tides are causing serious problems for New York that go beyond simple water damage. Answer Explanation: The answer is 'tropical storms', which are very large, powerful storms with extremely strong winds and heavy rainfall. Reason For Correctness: The correct answer is '(tropical) storms' because the text lists this alongside 'rising tides' as factors impacting New York. The table asks for 'the effect of' a specific factor combined with 'rising tides'; in the second paragraph, the passage mentions 'the impact of tropical storms and rising tides'. Since 'impact' is a synonym for 'effect' in this context, the missing words are 'tropical storms'. |
| Q29 | flooding | The position of the city - situated where the Hudson River flows into the Atlantic Ocean - already puts America's most densely populated city at a higher risk of flooding | Excerpt/Passage Explanation: The passage explains that New York's location between the Hudson River and the Atlantic Ocean causes a greater danger of water overflowing into the city. Answer Explanation: The answer means when a large amount of water covers an area that is normally dry land. Reason For Correctness: The correct answer is chosen because the text states that New York's location makes it very likely to experience water covering the land. The passage uses the phrase 'higher risk of flooding,' where 'higher risk' matches the table's 'increased chance.' This risk exists because the city is situated where a river joins the ocean. |
| Q30 | coastal erosion | The city is likely to face increasingly severe tropical storms crossing from the Bay as well as threats from coastal erosion and shifting clay soil | Excerpt/Passage Explanation: The passage explains that Bangkok will have to deal with very strong storms, the land by the sea being destroyed by water, and the ground changing its shape or moving. Answer Explanation: The answer 'coastal erosion' means the ocean water is slowly wearing away and removing the land near the coast. Reason For Correctness: The correct answer is correct because the passage describes the specific dangers Bangkok faces. It lists three main threats: big storms, 'coastal erosion', and the soil moving ('shifting clay soil'). The table already mentions the storms and the moving soil, so 'coastal erosion' is the missing piece of information that the passage provides. |
| Q31 | 29 cm | It seems unlikely that Bangkok will save itself from drowning under the waters of the Pacific, which are predicted to rise by between 19 and 29 cm by 2050 | Excerpt/Passage Explanation: The passage explains that the city of Bangkok is in danger because the Pacific Ocean is expected to increase in height by an amount between 19 and 29 centimeters by the year 2050. Answer Explanation: The answer is the highest amount that the water in the Pacific Ocean is expected to go up by the year 2050. Reason For Correctness: The correct answer is found in the section discussing Bangkok. The passage states that the waters of the Pacific are expected to go up by a range of 19 to 29 cm by the year 2050. In the table, the phrase 'up to' indicates that we need the maximum number in that range, which is 29 cm. Key terms to notice are 'predicted' (meaning expected in the future) and 'rise' (meaning to go up). |
| Q32 | lake bed | The city is built on a dry lake bed in the valley of Mexico, and the council has condemned fifty structures since 2006 because of leaning, and approximately 5,000 homes and buildings are unstable | Excerpt/Passage Explanation: The passage explains that Mexico City is located on land that used to be a lake. Because the city is built on this dry lake bottom, many houses and buildings have become unsafe or started to tilt. Answer Explanation: The answer "lake bed" refers to the flat ground that remains at the bottom once a lake has completely dried up or been removed. Reason For Correctness: The correct answer is "lake bed" because the passage explicitly states that Mexico City was constructed on a "dry lake bed." This directly corresponds to the table's description, which asks where the city is situated regarding something that has "dried out." The passage links this specific geographical foundation—a dry lake bed—to the city's instability and sinking problems. |
| Q33 | water reserve / water | Again the reason is the depletion of the water reserve lying under the city | Excerpt/Passage Explanation: The passage states that taking away the water stored under the ground is the cause for the city sinking. Answer Explanation: The answer 'water (reserve)' refers to the supply of water kept under the ground that the city uses. Reason For Correctness: The correct answer is 'water (reserve)' because the passage explains that the city is sinking (subsiding) due to the 'depletion of the water reserve'. The word 'depletion' in the text has the same meaning as 'using up' in the table, and 'lying under' has the same meaning as 'beneath'. |
| Q34 | mouth | Originally a small fishing village built on swamplands surrounding the mouth of the Yangtze River, Shanghai's population has swollen to around 13 million people | Excerpt/Passage Explanation: The passage explains that Shanghai was first a small village for fishing, built on wet, soft ground near the point where the Yangtze River meets the sea. Answer Explanation: The answer 'mouth' refers to the place where a river enters the sea or a large lake. Reason For Correctness: The correct answer is 'mouth' because the passage describes the original location of Shanghai. It states that the city started as a fishing village on swamplands (which are a type of wetland) located around the 'mouth' of the Yangtze River. The table asks for the specific part of the river that Shanghai is built near, and the text provides this exact word. |
| Q35 | massive skyscrapers / skyscrapers | The expansion has been sustained by taking water from wells drilled into the aquifer under the city and by constructing massive skyscrapers | Excerpt/Passage Explanation: The passage explains that as the city grew, it used water from deep underground and built many very big, tall buildings. Answer Explanation: The answer is very large and tall buildings that are heavy. Reason For Correctness: The correct answer is ‘(massive) skyscrapers’ because the passage identifies two main causes for Shanghai’s sinking. The first reason is taking water from the aquifer (groundwater), and the second is building very large tower blocks. The text uses the phrase ‘massive skyscrapers’ to describe these buildings and also mentions the weight of ‘high-rise buildings’ as a contributing factor. The table specifically uses the word ‘building’ as an action, looking for the object being built. |
| Q36 | C | Standing on the high tourist promenade that runs the length of the waterfront, you may also notice that the level of the river is quite a bit higher than that of the buildings on the Bund | Excerpt/Passage Explanation: The passage says that if you stand on the tall walkway by the water, you might see that the river water is higher than the buildings in that area. Answer Explanation: The answer means that when you stand on the high walkway in Shanghai, you can see that the water in the river is at a higher level than the buildings nearby. Reason For Correctness: The correct answer is C because the passage explains what a visitor might see while standing on the 'tourist promenade'. It uses the word 'notice' to describe seeing the river level being 'higher' than the old buildings behind it. While the passage mentions other things like different building styles, it specifically highlights the unusual height of the river as a surprising observation linked to why the city is sinking. |
| Q37 | C | Beaches in the area will be swept away followed by the surrounding wetlands eventually becoming part of the sea; surrounding river estuaries will see an increase in the salt levels in the fresh water. All of this will affect the ecosystems in New York's immediate area and damage developments along the coast | Excerpt/Passage Explanation: The passage explains that beaches will disappear and wet land will turn into the ocean. It also says that the places where rivers meet the sea will become saltier. Finally, it notes that the water will hurt (damage) buildings (developments) by the sea. Choice C is not a predicted effect because it misses the word "damage." Answer Explanation: The answer is Choice C. The passage mentions that coastal buildings and construction projects (developments) will be *damaged*, but the buildings themselves are not a result (effect) of the city's problems. They are simply things that already exist and get hurt. Reason For Correctness: The correct answer is C because the passage lists several specific outcomes for New York. It mentions that beaches will be "swept away" (Choice B), wetlands will turn into sea water (Choice A), and salt levels will rise in "river estuaries" or river mouths (Choice D). While the text says these factors will "damage developments," the word "developments" refers to the buildings that are already there. Without mentioning the "damage," simply stating "developments along the coastline" does not describe a predicted result or effect. |
| Q38 | B | Houston was literally built on a foundation of sand up to several kilometres deep and loosely packed clay from river deposits formed from the erosion of the Rocky Mountains | Excerpt/Passage Explanation: The passage explains that Houston's ground is made of sand and clay. This clay was created when parts of the Rocky Mountains were broken down and moved by water. Answer Explanation: The answer means that the city of Houston sits on ground made of things that came from the Rocky Mountains. Reason For Correctness: The correct answer is B because the text says Houston is built on sand and clay. It specifically mentions that this clay came from the "erosion of the Rocky Mountains." This means pieces of the mountains were washed away by water and ended up where Houston is now. Materials like sand and clay under the city are the result of this natural process. |
| Q39 | D | Using GPS data from 24 measuring points throughout the country between 1995 to 2005 a research team were able to monitor the area of subsidence | Excerpt/Passage Explanation: The passage states that researchers used GPS measurements taken over a ten-year period in the past (1995 to 2005) to study the sinking of the land. Answer Explanation: The answer means that researchers looked at records and information from the past to figure out how much the city of Houston is moving downward. Reason For Correctness: The correct answer is D because the passage explains that a research team used GPS records from the years 1995 to 2005 to track the city's sinking. Because these years happened in the past, this information is considered historical data. The other choices are incorrect because the sinking does not happen everywhere at the same rate, it has only stopped in specific areas where water is no longer taken out, and the text only mentions water extraction as the cause for Houston, not the weight of buildings (which is mentioned for Shanghai instead). |
| Q40 | B | a vast complex of drains was built under the city to protect it from flooding by water running from the surrounding mountains | Excerpt/Passage Explanation: The passage explains that the pipes were made under the city to stop floods. These floods are caused by water moving from the mountains into the city. It does not say that the pipes lead back to the mountains. Answer Explanation: The answer B is the statement that is false. It incorrectly claims that the drain pipes go back to the mountains. Reason For Correctness: The correct answer is B because the passage says the water flows 'from' the mountains, but it never says the 'drains' go back to those mountains. Instead, the passage explains that the drains are located 'under the city' and are sinking because the ground is falling. Since the question asks for the statement that is NOT true, B is the right choice because it changes the meaning of where the water and the drains are located. |