Chapter 13 Notes
Running water as an agent of erosion would
include:
• Drops of water moving down a hillside
• The Mississippi River
• Water flowing from a melting snowfield
Limestone and marble are types of bedrock
dissolved easily by running water.
Materials carried in suspension by a river tend
to make the water muddy.
The discharge of a stream is the volume of
water flowing past a given point in a stream.
Streams of mountain regions and high
plateaus are likely to have V-shaped valleys,
rapid water flows, rapids and waterfalls.
In a relatively short period of time, a river has
formed a V-shaped valley. The bedrock is
most probably soft and the climate is wet.
The western divide for the Mississippi River
system is in the Rocky Mountains.
Headwood erosion is an important factor in
the process of stream piracy.
When a river flows into a lake the river is
most likely to deposit all of its sediments.
Fertile agricultural areas are characteristic of
many of the world’s flood plains.
Constructing spillways is a method of flood
prevention using back swamps to contain
the overflow.
Factors that directly affect the velocity of a
stream are:
• The steepness of the slope down which the
stream travels.
• The amount of water traveling downstream.
• The number of meanders in the river.
Potholes form due to cutting tools such as
sand, pebbles, and small boulders moved by
running water.
Most of the material a river carries in solution
comes from the groundwater that seeps into
it.
A large increase in stream velocity is likely to
increase the stream’s competence and
capacity.
Stream discharge and velocity increase when
flooding occurs.
An alluvial fan forms when a steep mountain
stream meets dry, level land at the base of a
mountain.
The process of undermining is described as
the erosion of rock layers at the base of a
waterfall.
A curved body of water that forms when
deposits separate a meander from its river is
called an oxbow lake.
Replanting vegetation at the headwater
regions of a watershed is a flood prevention
method best for reducing runoff.
What has happened at line Y over the years?
Most river deltas occur where a river flows
into an enclosed or protected body of water.
Describe the conditions necessary for a
delta to form at the place where a river
flows into an open ocean.
The river must carry a lot of sediment. It must
carry more sediment than can be eroded by
the waves or ocean currents.
Describe why a river flowing near its base level is
likely to have meanders.
As a river nears its base level, less of its energy goes
to eroding down into the channel. Instead, the
river’s energy is deflected toward the sides of the
channel. Over time, meanders develop as the river
erodes away the outsides of river bends.
The river deposits material on the inside of the
river bend, and erodes the outside of the river
bend.