IELTS Reading 161: The City That Learned to Soak Up Rain

Adapted from Frontiers / SCIRP (Sponge City / SuDS). IELTS Reading Section 3 difficulty, approximately 1,050 words. Source: https://www.frontiersin.org/journals/water/articles/10.3389/frwa.2021.738493/full

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Reading Passage

A. When a heavy summer storm hits a modern city, the sequence is depressingly familiar. Rain falls on roofs, roads and car parks, none of which can absorb a drop. The water gathers in sheets, races down kerbs, and plunges into a system of underground pipes designed to carry it away as fast as possible. If the storm is ordinary, the pipes cope; if it is fierce, they fill to bursting, and the excess spills back into the streets, turning underpasses into lakes and flooding ground floors. For more than a century, engineers answered this problem by making the pipes bigger. Drainage systems were sized for a storm expected perhaps once in a year, and as cities densified those pipes were repeatedly outgrown. The result, repeated across the world's megacities, was that the very surfaces which made a city — concrete, tarmac, slate — also made it helpless against the sky. A storm that would have soaked harmlessly into a meadow became, over asphalt, a sudden and destructive wall of water. Climate change has sharpened the problem, because the downpours that overwhelm these old drains are arriving more often and more fiercely than the engineers who sized them ever predicted.

B. The idea now reshaping urban drainage turns the old logic inside out. Instead of moving rain away as quickly as possible, it asks the city to hold it, slowly, where it falls. The names differ from country to country — sustainable drainage systems in Britain, low-impact development in the United States, the "sponge city" in China — but the principle is shared. Rather than a pipe, think of a garden. Rain gardens are shallow planted depressions that catch water from a roof and let it sink into the soil. Bioretention basins act as sponges, filtering runoff through layers of sand and roots. Permeable pavements replace the solid tarmac of a car park with blocks whose joints let water through. Swales — shallow, grassy channels — carry flow gently downhill instead of hurrying it along a kerb. All of these measures do three things at once: they slow the water, so it arrives at a river long after the storm has peaked; they store some of it in the soil, recharging groundwater rather than denying it; and they filter the pollution that washed off the road before it reaches the stream.

C. China's sponge-city programme, launched in 2012, is the most ambitious test of the idea at scale. The strategy was a direct response to catastrophic urban floods that the old "grey" infrastructure — concrete canals and deep tunnels — kept failing to prevent. Rather than build ever-bigger drains, the country set out to make new and rebuilt districts absorb, use and clean rain on the spot. Planners spoke of retaining a high share of rainfall where it fell, combining green measures — wetlands, parks, swales — with the grey pipes that still handle the worst storms. The philosopher-engineer behind much of the thinking argued that cities should behave like the natural ecosystems they had paved over, accepting water rather than fighting it, and that a well-designed city would never try to defeat a storm but would learn to live with it. Early pilot cities reported reduced flood peaks, cleaner runoff and, importantly, a new kind of public space: the same sunken park that looked ornamental in summer was, in a storm, a reservoir. A single piece of land, on this view, could be a place to walk and a place to store water.

D. The shift is not without its complications, and engineers are frank about them. Green infrastructure demands land, and land in a dense city is the scarcest resource of all. A rain garden needs to occupy a plot; a permeable car park costs more than an impermeable one; a swale that looks delightful in a drawing still requires someone to maintain it, clear its silt and cut its grass. Critics point out that these measures work well for small and moderate storms but can be overwhelmed by the extreme downpours that a warming climate increasingly delivers, so the most resilient cities do not abandon grey pipes but combine them — green measures for the everyday rain, hidden tunnels for the once-a-century deluge. Finance is another obstacle. The savings from avoiding floods accrue to the whole city, while the cost of the new raingarden falls on a single developer, a mismatch that public subsidy is meant to close. The systems also work best when planned together across a neighbourhood; a single green roof on one block cannot save the next block's flooded underpass.

E. What the evidence suggests, a decade on, is that the sponge is not a substitute for engineering but a complement that changes its meaning. Milan and a growing list of European cities now treat rainwater as a resource rather than a nuisance, harvesting it to irrigate parks and cool the streets that concrete overheats. The same interventions that prevent floods also lower the urban heat-island effect, support wildlife and give residents somewhere pleasant to sit. This multiplicity of benefit is the real argument for the approach: a drainage measure that merely drains is invisible and forgotten, but one that doubles as a park, a cool space and a filter for polluted runoff earns its place on the crowded ground of a city. Where such schemes are well maintained, residents often come to prefer them to the bare, concrete drains they replaced, because a planted channel is also a pleasant one to walk beside. The older philosophy asked how fast water could be removed; the new one asks how slowly it can be kept. Cities that once fought the sky now try, in effect, to remember what soil does.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. Why concrete cities helpless against the rain ii. The new principle: hold the water where it falls iii. China's large-scale test of the sponge-city idea iv. The hidden cost of ever-bigger underground pipes v. The real complications: land, money and extreme storms vi. Why green roofs never work in practice vii. A complement that changes what drainage is for

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

Choose the correct letter, A, B, C or D.

5. How did traditional drainage systems respond to heavy rain? A. They let water soak into the soil. B. They channelled it away underground as fast as possible. C. They stored it on the surface. D. They used rain gardens.

6. What do rain gardens, bioretention basins and permeable pavements have in common? A. They all use underground pipes only. B. They slow, store and filter water where it falls. C. They increase urban flooding. D. They are cheaper than grass.

7. What was the aim of China's sponge-city programme? A. To build the world's deepest concrete tunnels. B. To make districts absorb, use and clean rainwater on the spot. C. To outlaw all new concrete buildings. D. To move people away from flood plains.

8. Why do engineers combine green measures with grey pipes? A. Green measures alone can be overwhelmed by extreme storms. B. Grey pipes are cheaper than gardens. C. Green measures cause floods. D. Grey pipes need no maintenance.

Questions 9-13

Do the following statements agree with the claims of the writer?

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

9. Traditional drains were often sized for a storm expected about once a year.
10. The sponge-city concept was first proposed in the United States.
11. Green infrastructure measures can also reduce the urban heat-island effect.
12. Sponge-city measures have completely eliminated flooding in all pilot cities.
13. Permeable pavements generally cost more than conventional tarmac.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

Instead of rushing rainwater away through pipes, modern schemes let it sink into (14) __________, recharging groundwater, while engineers stress that green measures must still be combined with hidden (15) __________ for the worst storms.

Answers & Explanations

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