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The Importance of Coastal Wetlands

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Presentation on theme: "The Importance of Coastal Wetlands"— Presentation transcript:

1 The Importance of Coastal Wetlands

2 The most common coastal wetlands are swamps and marshes.

3 Swamps are wetlands with mainly trees and shrubs. There is standing water with limited drainage.

4 Marshes are wetlands that are almost always flooded and have a mixture of cattails, reeds and other water plants.

5 What do coastal wetlands do for us?

6 Water Quality: Wetlands are one of nature's most efficient water filters. Wetland plants and soils clean the water before it goes into groundwater or into rivers.

7 Nurseries: Coastal near-shore wetlands serve as important nurseries for fish, crab, and other shellfish. This directly impacts commercial fishing, a huge industry in the United States.

8 Wildlife Habitat: They are home to many different kinds of animals. MuskratWood Ducks Wood Turtle

9 Storm surge buffers: Coastal wetlands knock down the storm surge which accompanies a hurricane and lessen the strength of hurricanes before the hit populated areas.

10 Erosion control: Barrier island marshes limit shoreline erosion and stabilize seashores.

11 Recreation: Coastal wetlands also provide a place for hiking, hunting, fishing, and bird- watching.

12 New Orleans: City at Risk

13 How could one of the largest and most important coastal cities in the U.S. get destroyed by a hurricane?


15 The pink areas are built below sea level. And why is that?

16 The French built New Orleans on the high banks of the Mississippi River. (1726)

17 The first area settled was called the “French Quarter.” It was built on high ground by the Mississippi River.


19 Jackson Square

20 1798

21 Swamps and marshlands were left empty in early New Orleans.

22 In 1803, New Orleans became part of the U.S. through the Louisiana Purchase.

23 Even 150 years after the city started, the marshes and swamps were mostly empty. (1878)

24 In the late 1890s, canals were dug to partially drain the swamps.

25 Through a system of drainage canals and levees, the swamps were turned into dry land and the city grew.

26 But the only thing keeping the city from drowning was the levee system.

27 National Geographic And the levees could not stand up to the storm surge of Katrina.

28 satellite images of New Orleans After Katrina looked like this Before had looked like this.

29 So, 100+ years of building on former swamplands – and not being able to adequately protect them – led to much of the deadly flooding.

30 GEOGRAPHIC LESSON: STOP DESTROYING the natural “buffer zone” between the ocean and the occupied land.

31 deposited rich silt at the mouth of the river. Louisiana originally had miles and miles of coastal marshes. These came from the Mississippi River’s delta as the river

32 Hurricanes gain energy from the heat of warm water in the Gulf of Mexico. So when a hurricane travels over the marshlands, it loses some energy BEFORE it hits populated areas.

33 Scientists sometimes refer to coastal mashes as “nature’s speed bumps” for hurricanes.

34 Scientists also tell us that for every 3 miles of marshland, a hurricane’s storm surge is knocked down by 1 foot -- before it hits populated areas.

35 But humans have been draining the marshes over the past many years. That turns marshes into solid land, and people move in.

36 And canals they built further erode the marshlands. Old marshes are turning into open ocean.

37 Concrete levee systems also prevent silt from naturally rebuilding the delta. Louisiana is losing 25 square miles a year of marshlands.

38 Rock jetties are now used in some places to slow marshland erosion.

39 And the U.S. Corps of Engineers has actually built pumping sites to pump silt-filled Mississippi water over the levees & into the marshes.

40 Protecting – and rebuilding – coastal wetlands will help us with water quality, erosion control, and protection against hurricanes.

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