VOA慢速英语--湿地如何帮助路易斯安那州抵御强海洋风暴

A complex and costly¹ flood prevention system helped protect New Orleans when Hurricane Ida hit the Louisiana city last week. Barriers, or seawalls, pumps and other controls blocked major flooding as the sea level rose sharply during the powerful storm.

But something else helped keep the water out of the city: the area's coastal² wetlands. These expanses of earth are covered in shallow water most or all of the time. Many kinds of animals, grasses and other plants make up the ecosystem³. The Louisiana wetlands slowed, redirected and helped contain the flow Ida that pushed in from the Gulf⁴ of Mexico.

"There is always a benefit by having these wetlands between you and the storm," said Gerald Galloway. He is a former engineering professor and an expert on flood risks. He has served as an advisor⁵ to the U.S. Army Corps⁶ of Engineers.

The wetlands had been shrinking for many years in Louisiana. The state launched a major effort to renew the area and barrier islands after the disastrous⁷ hurricanes Katrina and Rita of 2005.

How do natural barriers protect against storms?

The plants and uneven⁸ ground of wetlands are part of the strong storm resistance the ecosystem provides. These elements slow and weaken the water and winds as the storm moves inland toward people and property.

Hugh J. Roberts is chief operating officer at the Water Institute of the Gulf, an environmental research group. He said wetlands "help with storm protection because they are dissipating energy." In other words, wetlands help absorb the storm's energy.

What about big storms like Ida?

Wetlands are generally most effective at lessening⁹ the harm from small to moderate surges of ocean water, said Ed Link. He is a researcher at the University of Maryland. He also was the leader of an examination of New Orleans' storm protections' after Hurricane Katrina.

With bigger storms like Ida, the protection the wetlands can offer may be more limited. Once the wetlands are full of water, they lose their ability to slow down waves. Storms can more easily travel over them, Link said.

Still, experts say natural barriers offer one more line of defense¹⁰ even with major storms and they can make a difference.

How is the state improving natural defenses?

Louisiana has been spending large amounts of money to restore its natural barriers to help protect against storms. Since 2007, the state has created or restored around 197 square kilometers of marshland and 97 kilometers of barrier island. Marshland is a kind of soft wetland.

The state's most recent coastal protection and restoration plan includes several projects that build or protect more than 2,072 square kilometers of land. The total cost of such work is estimated to be $50 billion. But the projects are expected to prevent more than $150 billion in damage over the next 50 years.

Is the restoration working?

Even with such efforts, the state's restoration work cannot keep up with its land losses.

Louisiana has been losing land since at least the 1930s. Flood control measures along the Mississippi River stopped the natural process that left materials from the river in the delta¹¹ – the low-lying land next to the river. In 2012, state officials predicted their restoration work would someday stop the problem. Five years later, they were no longer making that prediction.

The Louisiana Coastal Protection and Restoration Authority now says the restoration is simply slowing down the land loss.

Words in This Story

shallow - adj. having a small distance to the bottom from the surface or highest point

absorb - v. to take in (something, such as a liquid) in a natural or gradual way

restore - v. to bring (someone) back to an earlier and better condition; to return (something) to an earlier or original condition by repairing it, cleaning it

1 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

2 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

3 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

4 gulf   

n.海湾；深渊，鸿沟；分歧，隔阂

参考例句：

• The gulf between the two leaders cannot be bridged.两位领导人之间的鸿沟难以跨越。
• There is a gulf between the two cities.这两座城市间有个海湾。

5 advisor   

n.顾问，指导老师，劝告者

参考例句：

• They employed me as an advisor.他们聘请我当顾问。
• The professor is engaged as a technical advisor.这位教授被聘请为技术顾问。

6 corps   

n.(通信等兵种的)部队；(同类作的)一组

参考例句：

• The medical corps were cited for bravery in combat.医疗队由于在战场上的英勇表现而受嘉奖。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

7 disastrous   

adj.灾难性的，造成灾害的；极坏的，很糟的

参考例句：

• The heavy rainstorm caused a disastrous flood.暴雨成灾。
• Her investment had disastrous consequences.She lost everything she owned.她的投资结果很惨，血本无归。

8 uneven   

adj.不平坦的，不规则的，不均匀的

参考例句：

• The sidewalk is very uneven—be careful where you walk.这人行道凹凸不平—走路时请小心。
• The country was noted for its uneven distribution of land resources.这个国家以土地资源分布不均匀出名。

9 lessening   

减轻，减少，变小

参考例句：

• So however much he earned, she spent it, her demands growing and lessening with his income. 祥子挣多少，她花多少，她的要求随着他的钱涨落。 来自汉英文学 - 骆驼祥子
• The talks have resulted in a lessening of suspicion. 谈话消减了彼此的怀疑。

10 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

11 delta   

n.（流的）角洲

参考例句：

• He has been to the delta of the Nile.他曾去过尼罗河三角洲。
• The Nile divides at its mouth and forms a delta.尼罗河在河口分岔，形成了一个三角洲。