River Systems

What’s the most COMMON agent of Erosion? Water

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!

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

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!

How do Rivers Flow?

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!

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!

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!

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)

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

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

Dendritic Drainage

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

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.

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

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

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.

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!

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