Transcript Surface Water PowerPoint2

Freshwater
Sections 9.2 & 9.3
Stream Development,
Lakes, Wetlands
Headwaters: Region where water
first accumulates to supply a stream.
Common to be high in the mountains
where falling precipitation accumulates in
small gullies and forms briskly moving
streams
Headwaters
Stream
Headwaters
http://www.2steger.de/canada/40_Stein_Valley_Traverse.htm
Stream
Headwaters
Tundra Lake headwaters of Stein River Lytton, 1983 August 07 (British Columbia, Canada)
people.uleth.ca/~holzmann/photos/index.html
Stream Channel: Narrow pathway
carved into sediment or rock by the
movement of surface water.
Stream Bank: Ground bordering
each side of a stream that keeps the
moving water confined
Stream
Stream
Banks
Banks
Stream
Channel
http://www.littleriverbigfuture.org/images/In%20txt%20pics/Stream_erosion_1.jpg
Immature River: Young river erodes
path through sediment or rock forming a
V-shaped channel.
V-shaped channels have steep sides and
sometimes form canyons or gorges.
Inner gorge of the Grand Canyon, located in northwestern Arizona. Carved by the power of the Colorado River, the canyon stretches for
277 miles. http://www.scienceclarified.com/landforms/Basins-to-Dunes/Canyon.html
Stream Valleys
• A new stream or river will
begin to carve a V-shaped
valley through the rock it
flows past.
• These are also young and
immature rivers.
– Ex. Grand Canyon
• Will continue until it
reaches another body of
water.
• Through time sides of river
will become wider and
broader.
Mature River: As the river becomes
more mature, the V-shaped valley will be
eroded away forming a broader, wider
river.
This bridge across the Danube River links Hungary with Slovakia
http://en.wikipedia.org/wiki/Image:MariaValeriaBridge.jpg
Meander: A bend or curve in a stream
channel caused by moving water
Meanders of the Rio Cauto at , Cuba.
http://en.wikipedia.org/wiki/Image:Rio-cauto-cuba.JPG
•Water in the straight parts of a stream flows at
different velocities depending on the location of
the water in the channel.
•Generally, water in the
center is flowing faster at
the maximum velocity while
water along the bottom and
sides flows more slowly
because it experiences
friction as it moves against
the land.
• The water moving along the outside of a meander
curve experiences the greatest rate of flow within the
meander.
• The water that flows along
this outside part of the
curve continues to erode
away the sides of the
streambed, thus making
the meander larger.
• Along the inside of the
meander, the water moves
more slowly and deposition
is dominant.
Oxbow Lake: A lake formed
from a cut-off meander
•After some degree of
winding it is common for a
stream to cut off a meander
and once again flow along a
straighter path.
•The stream then deposits
material along the adjoining
meander and eventually
blocks off its water supply.
•The blocked-off meander
becomes and oxbow lake,
which eventually dries up.
http://homepage.ntlworld.com/harry.wickens/borneo/borneo070.jpg
http://www.gly.uga.edu/railsback/1121RiverOxBow.jpeg
Alluvial Fan: Sloping depositional features
formed at the bases of slopes and composed
mostly of sand and gravel.
•Streams that lose velocity also lose their ability to carry
sediment.
•In dry regions mountain streams commonly flow down
narrow valleys onto broad, flat, valley floors. As a stream
flows from the mountain to the flat valley, the stream’s
gradient** may suddenly decrease causing the stream to
drop its sediment as a fan-shaped deposit.
•**A stream’s gradient is the difference in elevation between two
points on the stream divided by the distance along the stream
(Essentially the slope of the stream)
http://www.tulane.edu/~sanelson/images/allfan.gif
http://en.wikipedia.org/wiki/Image:Alluvial_fan_01.JPG
Delta: When a stream enters a large body of
water (example: an ocean), the stream looses
its velocity and the stream’s load is deposited in
a triangular shape.
•Usually silt and clay particles
•As a delta develops, sediments build up and slow
the stream water, sometimes even blocking its
movement.
•Smaller distributary streams then form to carry the
stream water through the developing delta.
http://www.sln.org.uk/geography/schools/blythebridge/delta.jpg
http://earth.usc.edu/~slund/systems/topic7pics/image9.gif
The Mississippi River Delta
http://serc.carleton.edu/images/research_educati
on/katrina/map_of_delta.v2.gif
http://earthobservatory.nasa.gov/IOTD/view.php?id=2521
Lake: A depression that collects and holds
water.
•Lakes accumulate water from streams, runoff,
precipitation, and springs.
•A small lake is a pond.
Reservoir: A man-made structure used for
storing water for later use. (Public water use,
recreation, flood control, etc.)
1st A sturdy dam is built.
2nd A stream is allowed to flow behind the dam
and will eventually fill the area with water.
Falls Lake Reservoir in N. Raleigh
Falls Lake; www.saw.usace.army.mil/falls/index.htm
Wetland: A land area that is covered with
water for a large part of the year.
•Include bogs, marshes, and
swamps
•They filter and trap
pollutants (from runoff),
sediment and bacteria to
improve water quality
•They are home to birds,
wildlife, fish, shellfish and
crabs.
•In NC, more than 70% of
the species at list depend on
wetlands!
http://www.iwla.org/index.php?id=416
http://i197.photobucket.com/albums/aa19/forjerz/Sunday-080.jpg
http://dcm2.enr.state.nc.us/ncwp/aerial.jpg
http://h2o.enr.state.nc.us/ncwetlands/gbheron.JPG
http://h2o.enr.state.nc.us/ncwetlands/swsms.html
Estuary: Where a feshwater
stream or river enters the ocean
•The water in estuaries is a mix of freshwater and salt
water called brackish water.
•Estuaries are nurseries to the young of many different
species including ocean fish species.
•Some large
estuaries include
the Chesapeake
Bay in
Maryland/Virginia
and the Pamlico
Sound in North
Carolina.
Chapter 10
Groundwater
% of Fresh Water
So only about 0.3% of the fresh water is
actually “useable.”
3. The source of all water on land is the
oceans through the water cycle.
4. Infiltration is when precipitation falls on
the land and enters the ground to become
groundwater.
5. Porosity is the percent of pore space of a
material.
6.The zone of saturation is the depth below the
surface where groundwater fills the pores.
7. The water table separates the zone of
saturation from the zone of aeration.
8. The zone of aeration is the area where the
pores are filled with air.
9. Permeability is the ability of a material to let
water pass through. (Impermeable -not able to
go through)
10. An aquifer is a
permeable
underground layer
which groundwater
easily flows through.
Example-the Ogallala
Aquifer in the Midwest
Section 10.3 Groundwater Systems
1. Groundwater typically stays underground for
hundreds of years. It moves slowly, steadily
through aquifers.
2. A spring is a natural discharge of groundwater.
3. A hot spring is a spring with temperatures
higher than the human body. Usually near
recent igneous activity
4. A geyser is an explosive hot spring that erupts
at regular intervals. Ex. Old Faithful in
Yellowstone
Geyser & Springs
Old Faithful in Yellowstone
5. A well is a hole
dug or drilled into
the ground, into an
aquifer, to tap a
reservoir of water.
Our Limited Water Supply!
1. First, the amount of water on Earth is a finite amount,
meaning that there will be no more made.
2. We need to conserve the water that we have, whether
city water or well water.
3. List all of the things that water can be used for:
4. Water restrictions are imposed to help limit the amount
of water that is used.
5. What restrictions have you heard of?
6. What are other ways that you and your family can
conserve water?
Threats to Our Water Supply!
1. Overuse of the water supply can cause the water
table to lower and it can “run out”!
2. Pollution is a problem in our water. They can be
polluted by sewage, landfills, agricultural or industrial
chemicals. Point source pollution is any single
identifiable source of pollution from which pollutants
are discharged, such as a pipe, ditch, ship or factory
smokestack Nonpoint is when we cannot tell the
origin.
3. How could these threats affect you and your family?
How does Non-Point Source Pollution affect our
waterways?
•NPS pollution degrades water quality! The pollutants that
enter storm sewers go directly to our lakes, streams, and
rivers, NOT to a water treatment plant.
•Eroded sediment clogs streambeds, destroying habitat for fish
and aquatic insects.
•Excess Nitrogen and Phosphorous, from fertilizers and
pesticides, cause extreme algae growth, fish kills, and
groundwater contamination.
•Human sewage and animal waste add harmful bacteria,
viruses, and excess nutrients that pollute the water.
• Water Resources
• Aquifer Depletion