Surface Water
Streams and Rivers
Stream Erosion and Deposition
River Valleys
Flood Plains and Floods
Tigris – Euphrates River
The Nile River
Yangtze River
Ganges River
Amazon River
The Mississippi River
Water Phase Changes
Hydrologic Cycle
Surface Water
VOCABULARY
Streams and Rivers
A river system consists of a river and all
of its tributaries.
tributary
river system
Tributary
Divide
drainage basin
watershed
divide
River
gradient
discharge
The drainage basin of a river system is all the land that is
drained by the river and its tributaries. A river’s velocity,
gradient, discharge, and channel shape affect how it
erodes and transports materials.
Important Definitions
River System – a stream and all its
____________
tributaries
Tributary – a smaller stream that empties
________
into a larger stream
Watershed – the land area drained by a
_________
river system
Divide – a high point that separates river
______
systems
River Channels and Drainage
There are different types of river channel
patterns and river drainage patterns.
1.
2.
3.
4.
Dendritic
Radial
Rectangular
Trellis
Dendritic network
A drainage network whose interconnecting streams
resemble the pattern of branches connecting to a deciduous
tree
Radial network
A drainage network in which the streams flow
outward from a cone-shaped mountain, and define a
pattern resembling spokes on a wheel.
Rectangular network
A drainage network in which the streams join each other at
right angles because of a rectangular grid of fractures that
breaks up the ground and localizes channels.
Trellis network
A drainage system that develops across a landscape of
parallel valleys and ridges so that major tributaries flow
down the valleys and join a trunk stream that cuts
through the ridge; the resulting map pattern resembles a
garden trellis.
Surface Water
Stream Erosion and Deposition
VOCABULARY
deposition
pothole
load
suspension
Rivers wear down Earth’s surface and
erode and deposit materials. A river
may carry materials in solution, in
suspension, and in its bed load.
bed load
Flow
competence
capacity
Suspension:
Silt and clay
delta
Bed load:
sand,
gravel,
pebbles
and
boulders
Materials carried in
solution cannot be seen.
Stream Load
A stream can carry its load in three
different ways:
solution – material is dissolved
1.________
2.__________
suspension – particles are held up by
stream’s moving water
bed load – material pushed or rolled
3._________
along the stream’s channel
How Streams Move Sediment
Surface Water
Stream Erosion and Deposition
Velocity and discharge affect how much
material a river can transport. When river
velocity greatly decreases, sediment drops out
of the water to form a delta or alluvial fan.
Over time, sediments
build up, forming a
delta.
Stream Discharge
Discharge is the amount of water that
flows past a point in a certain amount of
time.
Discharge is dependent upon velocity,
depth, and width of the stream.
velocity x _____
depth x _____
width
Discharge = _______
Vocabulary Summary
deposition
pothole
load
capacity
delta
A process
by which
materials is
dropped,
such as
sand or silt
by a
stream;
Deep oval
or circular
basins cut
into a
stream or
river bed
by
abrasion
from
swirling
sand,
pebbles,
and small
boulders.
The eroded
rock and
soil
materials
that are
transported
downstrea
m by a
river.
A measure
that
describes
the
maximum
size of the
particles a
stream can
carry.
A fanshaped
deposit
that forms
when a
river flows
into a quiet
or large
body of
water, such
as a lake,
an ocean,
or an
inland sea.
RIVER DEPOSITION
A river drops some of its load when either
its volume or its speed decreases eg when
it enters an arid (dry) region, crosses an
area of porous rock (eg limestone), enters
a flat or gently sloping plain or enters a
lake or the sea.
Material transported or deposited by a
river is called alluvium.
Alluvial
Fan – deposit formed when a
____________
stream spreads out onto a less steep area
Delta – where a stream empties
_____
into a larger body of water
Stream Stages
Youthful
________:
Rapids
Waterfalls
Fast-moving
water
Steep slope
Old
_______:
Broad
floodplain
Meanders
Oxbow lakes
Meander Scars
River Systems
Youthful
Mature
Old
Stream Processes and Floodplain Development
Surface Water
River Valleys
Youthful rivers form steep-sided canyons and Vshaped valleys. The lowest level to which a river
can erode its bed is called its base level.
Rapids can form as a
river runs down a deep
slope, while a river that
plunges over a cliff
forms a waterfall.
River Valley Terms
Headward
erosion
Base level
Stream piracy
The process by
which land is
worn away at the
head of gully or
stream valley.
The level of
the body of
water into
which a
stream flows.
The diversion
of the upper
part of one
stream by the
headward
growth of
another
stream.
Rejuvenation
____________ – when an old age stream
downcuts to “make it new again”
Forming Stream Terraces
Surface Water
VOCABULARY
flood
floodplain
meanders
oxbow lake
Floodplains and
Floods
A river that has cut down close to its
base level tends to erode the sides of
its valley, forming a meandering river
in a wide flood plain.
natural levees
Valley wall
Back swamp
flash flood
Oxbow lake
Meander
Natural
levees
Yazoo
tributary
floodplain
Meanders
________ – the bends and curves
of a stream
Oxbow
lake
deposition
erosion
Oxbow Lakes
Oxbow Lakes
Surface Water
Floodplains and Floods
River floods are natural events that can have
constructive as well as destructive effects.
People
have
developed
different
methods to
control and
prevent
river
flooding.
Floodplain and Natural Levee Development
Mississippi
River Flood
1993 Before
and After
Vocabulary Review
Flood: The phenomenon whereby a river overflows
its banks.
Flood plain: A wide, level area that borders a river
and is covered by its water during a flood.
Meander: Broad: looping bends in a river.
Oxbow lake: A crescent-shaped body of water
formed when sediments deposited by a river cut off a
meander from the river.
Natural levees: Elevated ridges along a river’s
bank that are formed by the deposition of the river’s
sediment load.
Flash flood: A sudden flood, usually caused by
intense, heavy rainfall.