Sometimes there doesn’t seem to be enough rain. Other times there is too much. Maybe thereisn’t a lot we can do to control the rain, but there is a lot we can do to reduce problems caused bydifferent rainfall patterns. A new development at the London Wetland Centre in Barnes solves the problems of managingwater with a “Rain Garden”. We are likely to be hearing about it a lot more often over the next fewyears. The idea is that the garden owner can store rainwater and use it in dry periods. They canreduce the problems caused by extra rain this way. One of the key problems that the rain garden tries to deal with is the problem caused by toomuch water in the street. In a natural environment, a lot of rainwater is sent back into the air byplants. Much is also absorbed deep into the ground, and flows into streams and rivers. What happensin city environments can be completely different —— a large amount of rainwater flows straight offthe hard surfaces of roofs and roads. The harder the rain, the less likely it will be absorbed into theground —— floods are the result. Rainwater running off roads is often polluted. The rain garden deals with living plants rather than hard surfaces. Plants are designed to holdwater and release it slowly, either into the ground, to be absorbed by plant roots (and so eventuallyback up into the atmosphere) or to go down into the water table. Not only does the rain gardenreduce the amount of water that flows onto the street, but it helps to clean it because plants are very goodat breaking down pollutants(污染物). 小题1:What’s the main idea of the first paragraph?
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