Millions of Americans are living in areas at high-risk of river flooding, many of whom are completely unaware of the danger.

While the risk of coastal flooding from extreme storms and rising seas rightly attracts plenty of attention, Americans are being urged to look inland for a similar threat receiving far less recognition: river flooding. New research conducted by the University of Bristol has shown that as many as 41 million Americans are highly at risk from river floods – more than three times the number previously estimated – with real estate (住宅区) in areas such as Louisiana, Florida, Arizona and West Virginia found to be especially at threat.

For the first time, it has been possible to produce super quality flood risk maps that cover the whole United States, while previous Federal Emergency Management Agency (FEMA) flood maps cover no more than 60 per cent of the country. The fine details provided by these new maps also makes it possible to predict the powerful effects of flooding on many smaller streams than before, thus raising concerns about the increasing number of people potentially threatened.

“We were all surprised by how many Americans we find are exposed to flooding from rivers,” says Oliver Wing, from the University of Bristol’s School of Geographical Sciences. “It’s particularly worrisome considering that most of these people aren’t even aware of the risk they face.”

Additionally, there is the possibility that this lack of awareness means construction in high-risk river flooding areas will continue to rise, despite the threats. Estimates (估量) suggest that projected population growth, continued urbanization trends (城市化趋势), and the unpredictable threats caused by climate change will leave over 60 million Americans vulnerable (易受攻击的) to a 100-year flood by the middle of the century. ‘All of this highlights the urgent need for large areas of floodplain and flood risk management planning,’ adds Wing.

【小题1】Which paragraph best supports “the risk of river flooding”?

A．Paragraph 1.	B．Paragraph 2.
C．Paragraph 3.	D．Paragraph 4.

【小题2】Which is true about the new maps?

A．They cover over 60 per cent of the United States.

B．They contain details of the flooding effects.

C．They make the river flooding under control.

D．They make the threats of rivers clear for the public.

【小题3】What can we know from the last two paragraphs?

A．People need management planning against the risk.

B．Most people are aware of the risk of the river flooding.

C．Climate change is the main cause of river flooding.

D．The threats keep people from construction near river flooding areas.

【小题4】What is the passage mainly about?

A．A research on the risk of river flooding.

B．The rising threats of coastal flooding.

C．Unpredictable threats caused by climate change.

D．Reasons for people’s unawareness of the risk.