surface water t ext book page # 318 – 325 what is a river system? a river system includes a river...
TRANSCRIPT
What is a river
system?
A river system includes a river in addition to any streams or tributaries that flow into that river.
Tributaries• Flow downward toward the main river.
• What force causes this?
• Pulled down by the force of Gravity!
Lakes and Ponds• Bodies of fresh
water
• Contain still or standing water
• Lakes and ponds form when water collects in
hollows and low-lying areas of
land.
PondsPonds are thriving
habitats for various plants and animals.
Algae serves as food for many animals.
Ponds are typically very shallow and sunlight can reach plants on the bottom.
LakesLakes are bigger
and deeper than ponds.
Sunlight does not reach the bottom in a deep lake.
Lake bottoms consist of sand, pebbles and rock.
LakesLakes can form from:
1. Cut-off meandering rivers (Oxbow lakes)
2. Erosion by ice (eg. The Great Lakes)
3. Extinct volcano craters (eg. Crater Lake, Mount Mazama – Oregon, USA)
4. Movements of Earth’s crust (eg. Lake Tanganyika and Lake Victoria in Central Africa)
5. Manmade lakes are formed by river dams.
Lakes- Human Uses• Drinking water
• Irrigation
• Boating
• Fishing
Reservoir- A lake that stores water for human use.
Lake Turnover
When the water in a lake mixes due to temperature change causing minerals, plant matter, and other nutrients to rise to the surface.
This refreshes the nutrients of the lake.
EutrophicationWhen nutrients build up in a lake over many
years.
Algae forms a thick green scum on the surface of the water.
Icebergs
Large chunks of ice that break off of a glacier and float away into the ocean.
Made of frozen FRESHWATER.
Three types of freshwater wetlands
1. Marshes
•Are usually grassy areas covered by a shallow water or a stream.
•Team with cattails and other tall, grasslike plants.
Three types of freshwater wetlands2. Swamps
•Look more like flooded forests, with trees and shrubs sprouting from the water.
•Located in warm, humid climates, where trees grows quickly.
Three types of freshwater wetlands3. Bogs•More common in cool, Northern areas.
•Often form in depression left by melting ice sheets thousands of years ago.
•The water in bogs tends to be acidic, and mosses thrive in these conditions.