1. Flood Control and erosion prevention

2. What is flooding?
Flooding is when a river or lake breeches its limits (overflows) due to large amounts of rainfall

3. How can you prevent flooding?
Flooding may be prevented by levees, which are large concrete walls that may surround lakes

4. But sometimes, they break….

5. The break in the levees

6. Lower French Quarter

7. Overlook of downtown New Orleans

8. Interstate in New Orleans

9. dams
What are dams?
A dam is a barrier that stops flowing water, causing the flowing water to slow, and creates a lake or a reservoir
They may be built to prevent large amounts of flooding

10. Purposes of dams Prevent large amounts of flooding
Water for irrigation (watering crops)
Hydroelectric power (water energy)

11. Hoover Dam

12. Hoover Dam, Colorado

13. Drawbacks of dams… What are some drawbacks (negative) of dams?
They stop rivers from flowing, therefore stopping deposition from the rivers
If deltas stop getting sediment from deposition, the ocean will erode them

14. Smaller flood controls
Sandbags (bags of sand) are used to prevent smaller floods.
Why?
Sand is very absorbent, and will absorb the flood waters, preventing the water from harming the interiors of buildings or further flooding

15. .

16. Contour strip cropping
Growing crops in narrow strips at right angles to prevent wind and water erosion

17. Contour Strip Cropping
Contour Strip Cropping is a human intervention to prevent or slow down erosion by planting strips of grass (vegetation) in between the rows of crops.
The vegetation helps to prevent the fertile topsoil from being eroded by the wind.

18. Deltas- a constructive force
The place where a river meets a larger body of water such as a lake or ocean.

19. Deltas

20. deltas

21. Mississippi Delta

22. Tacoma, Washington delta

23. Georgia’s barrier islands

24. What is the purpose of barrier islands?
Barrier islands are actually “erosion fighters”
How?
They protect or slow down the coastlines from being eroded by the rising sea levels
They also protect the mainland from severe storms

25. Layout of a barrier island