Transcript watercycle and erosion powerpoint

Chapter 2: The Flow of
Freshwater
Draw the water cycle diagram in
your daybook and label it in your
own words.
p.41 in your text
How is the Earth’s Water
Distributed?
How does this freshwater flow
across the surface of the earth?
RIVERS
• Rivers? Streams? Creeks? They are all
names for water flowing on the Earth's
surface
• Where does the water come from to fill
these???????
The Water Cycle
• The continuous movement of water from
the ocean to the atmosphere to the land
and back to the ocean.
Model of river running from the
mountains to the sea.
Parts of a River System
Continental divide of the United
States
• River systems are divided
into regions called
watersheds or drainage
basins
• This is the area of land
that is drained by a water
system.
• River systems are
separated from each
other by areas of higher
ground called a divide.
Drainage of river systems
Cross section of a River
Definitions
• Tributary: a stream that flows into a lake or into
a larger stream
• Channel: the path that a stream follows
• Bed: the bottom of the stream
• Load: the materials carried by the stream
– Bed load: the materials carried along the bottom of
the stream
– Suspended load: materials carried in suspension
(floating in the water)
– Dissolved load: materials carried in solution, they
usually cannot be seen.
Bed flow and direction
• In your daybook, draw
a cross section of a
river and label the
following parts:
• Channel
• Bed
• Banks
• Flood plain
• Bed load
• Suspended load
• Dissolved load
How do these rivers form?
• Erosion: the process by which soil and
sediment are transported from one
location to another.
• It can be transported by wind, water, ice or
gravity.
Where is this and how did it form?
The Grand Canyon and it was all
formed by EROSION !!!!!!
STREAM EROSION
• As a stream forms it erodes soil and rock
to make a channel.
• When first forms it is usually narrow and
steep. Over time the stream transports
more rock and soil downstream and
makes the channel wider and deeper.
• When streams become longer and wider
they are called rivers.
Factors that influence a streams
ability to erode
• Gradient: measure of the change in
elevation over a certain distance (how
steep it is)
• Discharge: amount of water that a stream
or river carries in a given amount of time.
• Load: the materials carried by the stream.
3 stages of a River
1. Youthful River
2. Mature River
3. Old River
4. Rejuventated
River
Characteristics of a Youthful River
• Channel is eroded
deeper rather than wider
• Water flows quickly
because it has a steep
gradient
• Has rapids and waterfalls
• Have very few tributaries
• HIGH erosive energy
Youthful River
Yosemite National Park
Characteristics of a Mature River
• Erodes channel wider
rather than deeper
• Does not have a
steep gradient
• Few rapids or
waterfalls
• Has many tributaries
• Has more discharge
than a youthful river
• Has meanders
Meandering Stream
• Mature rivers curve back and forth. The
bends in the river are called meanders.
Mature River
Characteristics of an Old River
• Low gradient and low
erosive energy
• Instead of widening
and deepening its
banks, river deposits
it soils in and along its
channel
• Have wide flat flood
plains (valleys)
• Has few tribuataries
Old River
Rejuvenated River
• A river whose gradient (steepness) has
been raised by tectonic activity (movement
of the crust of the earth).