1. River Systems

2. What’s the most COMMON agent of Erosion?
Water

3. Water Erosion
Water Erosion is most evident in the VALLEYS that RIVERS have carved into Landscape.
These Valleys are among the most HEAVILY POPULATED regions of the planet!
Valleys have FERTILE SOIL because Rivers carry loads of SEDIMENT down to the Ocean
Streams and Rivers are also a convenient means of Transportation!

4. What’s the Use?
Canada’s great Rivers were the Highways of the Historic FUR TRADE
In this Lesson, we will learn about the characteristics, importance and issues of some of the World’s major RIVER SYSTEMS

5. Great Rivers!
River System is the term given to the network of Streams and Lakes that eventually form one river.
Example: Saint Lawrence, Amazon, etc.
Maps always show a fine Blue Web of rivers!

6. How do Rivers Flow?

7. River Flow
River Systems flow from HIGH PLACES called the Source or Headwaters
They flow to LOW PLACES called the Mouth or Outflow
Gravity is the key!

8. River Flow
Some river MOUTHS are long, tapering inlets, such as the Saint Lawrence River
This is a DROWNED River Mouth, indicating that either the ocean levels have risen, or that the land has sunk!

10. River Flow
Other Rivers, such as the Ganges River in India, have deposited low-lying DELTAS of fine SEDIMENTS at their Mouths.
This material has been Eroded from the land Upstream and brought Downstream by the current of the River!

12. The World’s Longest River Systems!
River and Continent
Length (km)
Outflow
Outflow Location
Nile (Africa)
6670
Mediterranean Sea
Egypt
Amazon (South America)
6570
Atlantic Ocean
Brazil
Yangtze (Asia)
5980
East China Sea (Pacific)
China
Mississippi-Missouri (North America)
5970
Gulf of Mexico
U.S.A
Yenisey (Asia)
5870
Gulf of Kara Sea (Arctic)
Russia
Amur (Asia)
5780
Tatar Strait (Pacific)

13. Drainage
The entire Region Drained by one River System and all of its parts
An Area characterized by all runoff being conveyed to the same outlet.
Synonyms: Basin
Catchment Area

14. Drainage Patterns
Rivers are part of a larger natural system that continually recirculates the Earth’s water.
Canadian Rivers are fed by MELTING SNOW in the early Spring and by RAINFALL the rest of the year.
Rivers Carve 2 Distinct different Patterns as they carry surplus moisture from the land!
Dendritic and Trellis drainage patterns are the result of different Landforms and underlying Rocks

15. Dendritic Drainage

17. Dendritic Drainage The most common type of drainage
If rivers cross a gradual slope over one basic type of rock, this Tree-Like pattern will be cut into the landscape
The main stem of the river points downstream to the mouth, and each “Branch” joining the main river is called a Tributary

20. Trellis Drainage Not as common as Dendritic
If river flows through ALTERNATING bands of hard and soft rock, a “Rectangular” drainage pattern develops!
This often occurs when a large River cuts through Parallel Fold Mountain ridges, such as the Appalachian or Rocky Mountains.

22. Pollution of Drainage Basins
The entire area drained by one River System

25. Pollution
Pollution can easily occur in Drainage Basins because the waters are all CONNECTED
This is a particular problem in the Saint Lawrence Basin, because of the Great Lakes

26. Pollution
Heavy Industrial Sludge and Agricultural Fertilizers contaminate the waters and are passed DOWNSTREAM.
Millions of people live near the Great Lakes, and they rely on this water for Residential uses and Recreation.
Dangerous Chemicals collect in Channels and Lake Bottoms.

27. Pollution
These Chemicals and this pollution is very threatening to the natural habitats of a variety of animals as well as human health!
The Saint Lawrence Drainage Basin presents many serious environmental questions and concerns to both the governments of Canada and the U.S.A!

34. Some Help!
Pages 82 to 85 in your Text Book have some great information and pictures that could help you with your questions!