Transcript Freshwater Resources

Surface Water
Review
A. Glaciers and Icebergs
B. Wetlands
C. Ponds and Lakes
D. Streams and RIvers
1. Runoff
2. River Systems
3. Rivers Shape the Land
4. Profile of a River
5. Flood Plains and Floods
Water Phase Changes
Hydrologic Cycle
1.Glacier-huge mass of ice
and snow that moves slowly
over the land scraping and
reshaping it
a.Valley
b.
b. Continental
2. Iceberg-large floating
chunk of ice. Only 7%10% visible
1.An area of land covered with a
shallow layer of water for all or
part of the year
2. Sheltered waters rich with
nutrients provide great habitats
3.help control flooding
4.3 main types: bogs, marshes
and swamps
5.Florida Everglades largest
1. Form when water collects in hollows and
low-lying land areas
2. Ponds-shallow lake where sunlight
reaches the bottom
3. Lake-large body of water; usually deep;
formed in depressions like craters,
glacial deposits or from dams
(reservoirs)
4. Turnover-seasonal mixing of bottom and
top layers that refresh nutrients
5. Eutrophication-nutrient build-up causes
algae to overgrow
1.Runoff-water that flows
over the ground. Several
factors affect this flow.
a.Type of surface
b.Rate of rainfall
c.Slope of the land
2. River Systems
A river system consists of a river and all of its
tributaries.
Tributary
Divide
River
The drainage basin of a river system is all the land that is
drained by the river and its tributaries.
This is also called
a watershed . There are many but we live in the largest.
It is the Mississippi River Basin
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 -interconnecting streams resemble
the pattern that branches of a tree might
make
Radial network
Radial- streams flow outward from a coneshaped mountain, and make a pattern
resembling spokes on a wheel.
Rectangular
streams join each other at right angles
because of a rectangular grid of fractures that
breaks up the ground
Trellis-A system that develops across a
landscape of parallel valleys and ridges so that
major tributaries flow down the valleys and join
a trunk that cuts through the ridge; the
resulting map pattern resembles a garden trellis.
3. Rivers Shape the Land
a. River speed is a factor
that can be determined by
the:
1.Steepness of a slope
2.The channel it flows
through (this creates
friction)
3.Volume of water
b. Rivers wear down Earth’s surface and
erode and deposit materials like sediments. A
river may carry materials in solution, in
suspension, and in its bed load.
Flow
Suspension:
Silt and clay
Bed load:
sand,
gravel,
pebbles
and
boulders
Materials carried in
solution cannot be seen.
Erosion – wearing away of
1.________
materials
Deposition
2.__________ – soil and rock are
left
behind
Sediments
3._________ – rock and soil picked
up and dropped in erosion and
deposition
4. A stream can carry its load in
three different ways:
solution – material is dissolved
________
suspension
__________
– particles are held up
by stream’s moving water
bed load – material pushed or rolled
_________
along the stream’s channel
How Streams Move Sediment
c. The speed of a river determines
what drops out of the water to create
different landforms. These landforms
can be:
1. Canyons
2. Mudflats
3. Sandbars
4. Gully
5.
Alluvial
Fan
____________ – deposit formed when
a stream spreads out onto a less steep
area like at the base of a mountain
Write the definition down!
6. Delta
_____ – where a stream empties
into a larger body of water
Write the definition down!
4. Profile of a River
a. Headwaters-Beginning or river
source; fast water and narrow
canyons
b. Downriver-slope less steep;
tributaries increase water
volume; channel is wider and
deeper because of erosion
c. Flood Plain-broad, flat area
that has other river features
1. Meanders-looping curves
2. Oxbow lakes-crescents of
land cut off from the main
river
d. Mouth- Point where the
river flows into another body
of water (deltas, alluvial
fans)
Meanders
________ – the bends and curves
of a stream
Oxbow
lake
deposition
erosion
Surface Water
River Valleys
Youthful rivers form steep-sided canyons and
V-shaped 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.
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
Oxbow Lakes
Oxbow Lakes
Rejuvenation
____________ – when an old age stream
downcuts to “make it new again”
Forming Stream Terraces
5. 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.
Valley wall
Back swamp
Oxbow lake
Meander
Natural
levees
Yazoo
tributary
floodplain
Floods occur when the volume of water in a river
increases and overflows its channels.
River floods are natural events that can have
constructive as well as destructive effects.
They destroy habitats and homes but they leave
behind land rich in nutrients.
People have developed
different methods to
control and prevent
river flooding. One is a
man-made dam called a
levee
Floodplain and Natural Levee Development
Mississippi
River Flood
1993 Before
and After
Tigris – Euphrates River
The Nile River
Yangtze River
Ganges River
Amazon River
The Mississippi River
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.