1. Drainage Basins
Watersheds

4. What is a watershed? The area of land drained by any one stream
Includes the main river and all of its tributaries

5. What is a tributary?
A smaller stream that flows into a larger one

6. Tributaries
As water continues to flow through tributaries, it combines with more water.
So the size of the stream gets bigger and bigger A B

7. What happens to water when it hits the ground?

8. What causes water to flow?
Hint: Underlying force behind all erosion!
GRAVITY
So that means water always flows from high elevation to low elevation

9. What do the bold lines represent?

10. … divides between drainage basins

11. Label! Ontario Susquehanna Mohawk St. Lawrence Champlain
Long Island Sound
Allegheny
Erie

12. 4 of the watersheds feed into the St
4 of the watersheds feed into the St. Lawrence River, then into the Atlantic Ocean
A. Ontario D. St. Lawrence E. Champlain I. Erie

13. Where do the others go?
B. Susquehanna – Chesapeake Bay F. Long Island Sound – Atlantic Ocean C. Mohawk- Hudson River G. Delaware – Delaware River H. Allegheny – Ohio River

14. Susquehanna – Chesapeake Bay

15. Long Island Sound – Atlantic Ocean

16. Mohawk- Hudson River

17. Delaware – Delaware River

18. Allegheny – Ohio River

19. Watersheds fit together like puzzle pieces

20. Continental Divide
The United States is split into two large drainage basins

22. Mountains
Topography, like mountains, determines which watershed the rain will enter.

24. Drainage Patterns
Dendritic
Radial
Rectangular
Trellis

25. Dendritic Most common Looks like tree roots
It develops in regions underlain by homogeneous material (consisting of parts of the same kind)
The bedrock all has a similar resistance to weathering so there is not a path of least resistance
the resistance is equal in every direction

26. Dendritic

27. Radial Develops around a central elevated point
The pattern is commonly found on cone shaped features (Volcanoes)
Tributary streams start at the highest point (top of the volcano)

28. Radial

29. Rectangular Found in regions that have undergone faulting
Streams follow the path of least resistance
Faulting causes movement of the surface
Off-sets the direction of the stream
Tributary streams make sharp bends

30. Rectangular

31. Trellis Looks like a garden trellis Develops in folded topography
Down-turned folds called synclines form valleys in which the main channel of the stream flows
Short tributary streams enter the main channel at sharp angles
As the tributaries run down sides of parallel ridges

32. Trellis