Jonathan Karr
Characteristics
of River
- River
- Length: 4,000
miles (6,400 km)
- Volume:
- Carries 1/5
of all water carried off earth’s surface
- Flood-stage
discharge at river’s mouth: 6,180,000 ft3
- Path: West
to East / High Andes Mountains within 100 miles of Pacific Ocean to Atlantic
Ocena
- Main outlet:
north of Marajo Island, 40 mi (64 km) wide
- Negro is
largest tributary
- carries
1/5 of discharge of Amazon
- Tributaries
that rise in the ancient crystalline highlands (Jari, Trombetas, Negro,
Tocantins-Araguaia, Xingu, Tapajos) are termed “blackwater” because they
originate from acidic rains, are rich in humus, nutrient poor
- Madiera
brings “whitewater” filled with sediment
- Able to dilute
salinity of ocean for 100 miles from shore
- Basin
- Area: 2.3 million
square miles (6 million km2)
- 2/3 of
Basin lies in northern Brazil
- 45 % of
country is part of basin
- Ecuador
- Bolivia
- Venezuela
- Lowland / varzeas
(Portuguese)
- Area flooded
in a yearly cycle
- Borders main
river and tributaries
- Covered by
immense rain forest which transitions to dry forest and savanna in the West
- “Gently undulating
hills”
- Composed
of layers of alluvial soil deposited as much as 2.5 million years ago
- Many shallow
oxbow lakes and wetlands
- Average rainfall
60-120 in/year
- Atmosphere
- Main flux of
water vapour comes from east
- ½ of
precipitation that falls originates from Atlantic Ocean
- ½ of
precipitation comes from evapotranspiration from forest and storms
- Lowlands
average 60-120 in/year
- Dry season
exists, but not sufficient to stop plant growth
- High levels
in upper piedmont
- Highest level
in upper Putumayo along Colombian border
- Andes Mountains
to west form natural barrier which prevents water vapour from leaving basin
Source
"Amazon River" Encyclopædia Britannica <
http://www.search.eb.com/eb/article?eu=121415
> [Accessed September 30, 2002].
Links
Map of Amazon Watershed (Encyclopedia Britannica)
Table Comparing Lengths of World Rivers (Encyclopedia Britannica)
Table Comparing Drainage Areas of World Rivers (Encyclopedia Britannica)