EARTH SCIENCE 11
Name _____________________
RUNNING WATER & THE RIVER VALLEY
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I will understand the effects running water has on erosion
I will understand the various land formations of the river valley
Running Water:
• Includes all water that falls as _____ or _____ and then moves _______ hill under the force of
gravity
• Most ____________ in wearing down the surface of Earth
• The energy initially comes from the Sun which evaporates the water and lifts it high into the
atmosphere
Effect of Running Water
A. Running water attacks bedrock
• It carries rocks, pebbles, and sand, which then hammers and grinds away ___________
• “__________________”
• Grinding action is called abrasion
• It _______________ bedrock consisting of soluble minerals (calcite, halite)
• If the water is moving fast enough it can lift and split rock with ___________ action (usually flood
stage)
B. Running water removes weathered rock
• ____________ matter is carried in solution.
• Dissolved elements are usually calcium and magnesium.
• _______ material is carried in suspension.
• Fine material (clay, silt, fine sand) that is kept from sinking with turbulence.
• _______________ moved along the stream bed.
• Coarse material that rolls, bounces and slides along the riverbed. Sand, pebbles, boulders.
• As the rivers’ _________ increases, the _______ of the particles carried increases.
Carrying Power & Load
• Carrying power:
• the total amount of ______________ in the stream and the size of the particles being moved by
the stream
• Depends upon the _______ of the stream and its discharge
• Stream discharge:
• the __________ of water flowing past a given point in the stream at a given time
• Expressed in cubic meters per second
• High _________ and high ______________ can carry both a large amount of ________________ and
larger ________ of sediment particles
• The speed of a stream depends mainly upon the _______________ of its bed
• Speed also increases with increased _______________
• During floods the discharge of a river increases tremendously and its carrying power may be
__________ of times as great
THE RIVER VALLEY
Gullies
• A _____________ stream valley
• Usually caused by river tributaries that only flow when it _______ or the ________ melts.
• In time, with erosion and the accumulation of other gullies, the gulley may become a stream or river
V-Shaped Valley
• _______ moving water _______ into the valley floor
• The upper walls continue to ____________ due to weathering and tributary streams causing a
___ - shaped valley
Georges, Canyons, Chasms
• Steep valleys are called canyons, gorges, or chasms
• Canyon:
• a deep _________ with steep sides (Ex. Grand Canyon)
• Gorge:
• a deep _________ that usually has a river running through it
• Chasm:
• a deep _________ in the Earth’s surface
Base Level
• The base level of the valley is the level to which the river flows
• For streams that flow into an ocean, the final base level is sea level
• As the stream or river approaches its base level it slows and widens which results in a wider valley with
a broad floor and gentle sloping walls
Divides & Drainage Basins
• Divide:
• The high land that _____________ one valley from the next
• River System:
• A ________ and ____ of its tributaries
• Drainage Basin:
• Includes _____ of the land that __________ into the river
Stream Piracy
• Stream Piracy/Stream Capture:
• Is the result of stream lengthening until its headwaters _______ through a _______ and
________ the water from another stream
• Final result = large river systems
Water & Wind Gaps
• Water Gaps:
• As a river cuts into a valley, it may meet an unusually __________ rock formation
• As time passes, this rock formation will wear away more ___________ than the surrounding
rock
• Wind Gaps:
• Is a _________________
• May have formed when the water of the gap was captured by a neighboring river