Stream Development
Objective
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1. Define deposition as the process by
which Earth materials carried by wind,
water, or ice settle out and are deposited.
2. Describe the agents of erosion: gravity,
water (running water and waves),
glaciers, and wind.
3. Explain that running water (rivers,
streams, and runoff) is the major cause of
erosion.
Objective
4. Identify the sources of fresh water on
the Earth’s surface.
 5. Describe the process of stream
development and the associated
landforms.
 6. Design and construct experiments using
stream tables to infer relationships
between gradient, slope, speed, and
extent of weathering and erosion.
 7. Explain the types of deposition specific
to streams and rivers (such as alluvial
fans and deltas).
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Enduring Understanding
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Weathering, erosion, and deposition are
interrelated processes that form a cycle of forces
that wear down and build up the Earth’s surface.
Water is continuously passed through the
hydrologic cycle.
Fresh water is necessary for survival and most
human activities.
Stream Development
 As
a stream develops it changes
shape, width, and size as well as the
landscapes over which it flows.
Stream Development
 Streams
are responsible for the
majority of the landforms we see
today
Alluvial Fan
Stream Development
 Precipitation
supplies the water for
the beginnings of stream
development
Stream Development
 Headwaters
is the region where
water first accumulates to supply a
stream
Stream Development
 Headwaters
are commonly found
high in the mountains
Stream Development
 Stream
channel is a narrow pathway
carved into the sediment or rock by
moving water
Stream Development
 Stream
bank is the ground bordering
each side of the stream
Stream Development
 Stream
piracy occurs when one
stream draws away water from
another
Stream Valleys
 As
a stream actively erodes its path
through the sediment or rock it
develops a specific recognizable
landform
Stream Valleys
 V-Shaped
channels are formed by
streams and have steep sides that
form at an angle
Stream Valleys
 Gorges
and canyons are very old Vshaped channels
Stream Valleys
 The
Grand Canyon formed by the
Colorado River is one very
recognizable V-shaped valley
Stream Valleys
 Base
level is lowest elevation a
stream will cut its valley to and
coincides with the level of the lake or
larger stream it runs into
Stream Valleys
 Sea
level is the ultimate base level
Meandering Streams
 As
streams continue to cut and
widen their channels the amount of
water and sediment they can carry
increases.
Meandering Streams
 As
the stream approaches base level
the slope decreases and water builds
up it begins to erode the sides of the
channel.
Meandering Streams
 Meander
is the bend or curve in a
stream channel
Meandering Streams
 The
water flowing in a stream moves
at different speeds. It is fastest in
the middle of a straight flowing
stream because friction slows the
sides and bottom.
Meandering Streams
 When
a stream begins to make a
turn this changes and forms very
interesting features
Meandering Streams
 Water
on the outside of the curve
flows faster than the water on the
inside of the curve
Meandering Streams
 This
water erodes away the outside
bank and makes the meander even
larger
Meandering Streams
 Cut
bank is the result of the greater
erosion
Meandering Streams
 The
slower water on the inside of the
curve causes deposition of the
sediment
Meandering Streams
 Point
Bar is the resulting feature
Meandering Streams
 Oxbow
Lakes are meanders that
become completely blocked off by
deposition of sediment
Stream Deposition
 As
streams slow they lose their
ability to carry sediment. This is
most commonly the result in a
decrease in gradient or slope of the
landscape over which the stream
flows
Stream Deposition
 Alluvial
fan is the sloping deposited
sediment at the base of a steep slope
and is most commonly found at the
base of mountains in dry regions
Stream Deposition
 Delta
is the triangular deposit that
forms when a stream enters a large
body of water.
Stream Deposition
 Deltas
grow as stream deposition
blocks the pathway of the moving
water and smaller distributary
streams branch out to form their own
deposits
Stream Deposition
 The
Mississippi River delta began
forming millions of years ago but it
has deposited enough sediment in
just the last 5,000 years to build the
city of New Orleans on