Section 13.1 streams and rivers - Link 308
Download
Report
Transcript Section 13.1 streams and rivers - Link 308
Tributary
Is a stream that flows into a larger stream or
river.
River system is a river
and all of its tributaries.
- Also referred to as the watershed, is all of the
land that drains into a river system
A divide is a large landmass that separates two
drainage basins.
Ex. Rocky mountains.
3 factors that determine a streams velocity.
Velocity is the distance water travels in a
given amount of time.
gradient
discharge
channel shape
Gradient how steep or flat a river is.
The steeper the gradient the faster the river
will flow.
Discharge is the amount of water that passes
by a certain point in a given amount of time.
Discharge varies depending on the time of
year and the weather conditions.
Channel is the path that makes up a river.
The velocity of a river depends on the depth of
the channel, and how winding it is.
A shallow river with many boulders has a lot
of surface area contacting the river creating
friction and slowing the water down
Stream Erosion and Deposition
Depositon
The Process by which the material is
deposited
Pothole
Deep circular basin
developed when the
river develops small
whirlpools
Load
Downstream
Eroded rock and soil
By action of the river
Suspension
Muddy looking
Clay, silt and fine sand
In between the water molecules.
Bed Load
Rock transport
Capacity
Total amount of sediment the stream can carry
Competency
Maximum size of particle the stream can carry
Increase velocity more
movement
Decrease velocity
more deposition
Everything held by the
water will be
deposited.
Deposition
Fine sediment
River slows down to a body of water
Describe how rivers wear down rock
material.
How does a river’s velocity affect its
competence and capacity?
Under what circumstances do rivers and
streams deposit sediment?
A river carrying sediments in suspension
curves back and forth sharply. Predict what
you might find if you studied deposits on the
stream bed. Explain your predictions.
River Valleys
Land is worn away at the head of a
river/stream.
The level at which the stream can go down
to.
Set by the body of water the stream enters
Differential erosion.
Hard top
Soft under-strata
What is a flood?
When a river or stream overflows it’s banks
A floodplain is the area along a river that is
most susceptible to flooding.
A river flowing through a floodplain typically
winds back and forth is broad curves called
meanders
Created because erosion is most rapid on the
outside of a river bend and channel is usually
deepened there
As the water swings wider it could break
through a meander and result in an oxbow
lake: a curved body of water when deposited
sediments separate a meander from it’s river
Natural levees form when thick deposits of
sediments form ridges on the side of the river
after a flood.
Restoring natural plant life in areas along
rivers.
Dams can help to control the amount of
water moving downstream.
Artificial levees such as sandbags can be put
into place as a temporary solution.
Maintain safe floodplains by not allowing
people to develop the land in a floodplain.