1. World Geography 3202
Understand how running water acts as an agent of erosion and deposition. (Chapter 2)

2. Introductory Terms / Information
Tributaries are branches of a river that feed water into the larger river
Rivers flow from high elevation to low elevation
Rivers empty into the sea at sea level = 0 ft
Look for elevation legend, often color coded, symbols or contour lines.

3. Amazon River
What direction does the river flow? Where is the high elevation?
Where are the tributaries?
Where does the river begin?

4. Define the term drainage basin. (p. 26)
Drainage Basin = the area of land drained by a river and its tributaries.
Try question #4 p. 26

5. Drainage Basin-Circled in red

6. Drainage Basin. (p. 26)
The Amazon Basin is the planet's largest body of fresh water with 1100 tributaries 17 of which are more than 1000 miles long.
Many of the tributaries begin in Colombia and Peru.
WHY????

8. Nile River Basin
The Nile river in Africa is the longest river in the world.
The green area on the map marks the Nile River basin.

10. 1.3.1 Describe the three stages in the life cycle of a river. (P. 26)
Rivers change over time and seem to go through three stages:
1st Youthful rivers
2nd Mature rivers
3rd Old rivers

11. Young Rivers Usually found in highland or mountain regions
Steep slope (high gradient)
Small volume of water
Rapid flow of water
Rapid erosion
More vertical erosion than lateral
Narrow “V” shaped valley
Water falls & rapids common

14. Mature Rivers Most high relief is eroded Gentler slope
Many well developed tributaries
Broad flat river valley
Well developed flood plain
More lateral (↔) erosion than vertical
Meandering results

15. Late River Maturity Remember the stages are not distinct.
These changes occur over long periods of time.

17. Old River Almost no slope Very little relief Elaborate meandering
Often swampy areas around river
Very muddy due to slow speed and deposition
Most susceptible to flooding because of large flood plain.

19. The Amazon- What stage??

20. 1.3.2 Describe two ways in which water erosion occurs. (P. 31)
Vertical erosion makes rivers deeper as is the case in young rivers
Lateral erosion makes rivers wider leading to the meandering of mature rivers.

21. Youth Stage
Mature Stage
Old Age Stage

22. 1.3.4 Define the term Delta. (P.32)
low lying area at mouth of river
formed by deposition of silt
deposition occurs because river slows as it enters ocean or lake

25. Named from Latin word for curved in the shape of a bow.
* Distinguish among the terms arcuate delta, digitate delta and estuarine delta. (P. 32)
Arcuate Delta=
Named from Latin word for curved in the shape of a bow.
Fan shaped
Example Nile Delta p. 32

26. Nile
Delta

27. Digitate Delta Digitate Delta = From Latin for finger
Delta with long fingers of sediment reaching into the sea
Example Mississippi

28. Mississippi Delta

29. Estuarine Delta p. 32 Estuarine Delta =
Formed when river runs into bay or estuary
Tidal mud flats form which can be seen at low tide
Sediment deposited from river outflow and from Tidal inflow

30. Sacramento River – San Joaquin San Francisco Bay Delta

31. Delta Similarities & Differences
Arcuate & digitate both flow into open ocean
All three allow river water to flow out
All have channels or distributaries cut into them by the river
Differences
Estuarine empties into a bay whereas other 2 empty into open water
Three different shapes

32. 1. 3. 3. Examine evidence to determine the life cycle stage of a river
1.3.3 Examine evidence to determine the life cycle stage of a river. (P. 28 questions # 5 & 6)
Evidence to look for!!
Slope of the river
Relief of the banks
Width of the valley
Meandering
Size of flood plain
Rapids or water falls

33. What stage is this river in?
Young
Water falls & rapids
Steep slope

34. What stage is this river?
Early maturity
Some meandering
However still some relief
Associated with mountain

35. What river Stage? Youth Rapid water movement Rapids & water falls
High relief on banks