NAME: DATE:
ENVIRONMENTAL EARTH SCIENCE
STREAM SPEEDS AND EROSION/DEPOSITION
Visited a stream near your home and examined the way it
erodes and deposits material. Compare this stream to the one studied in class.
Use your notes, text, and your own reasoning to answer the
questions
after each of the following statements
1. The size of the sediment carried by a stream depends on
the speed
of the water. Will the stream studied in class carry
larger or
smaller particles than the stream near your home? Why?
2. Sediment carried by a stream scours the bed and sides
of the stream
channel. Which sides of the stream - the inside or the
outside of
the curves appeared to be more scoured?
3. A suspension is a mixture of water and particles in
which the
particles do not settle out because of the energy in the
motion of the
water. Silt is suspended in water that has any motion at
all, sand
is suspended and carried in fast moving water, and gravel
and rocks
are rolled along the bottom of fast moving water. What
size sediment
was the stream carrying? Why?
4. A solution forms when molecules occupy spaces between
water
molecules by dissolving into the water. Give an example
of three
substances that dissolve into water.
5. Suspensions usually appear cloudy, but solutions
usually appear
clear. Give an example of a beverage that is a solution
or a
suspension depending on what you add to it, describe how
it is
changed.
6. Dissolved materials are carried by streams no matter
what its
speed. Explain why streams continue to be agents of
erosion even when
they are moving slowly between storms.
7. Areas of slow moving water such as lakes, ponds,
swamps cause
sediments to drop out of suspension. Explain how ponds
turn into
wetlands.
8. Deposits of sediment are dropped and sorted by size as
the water
slows down: largest particles first, fine particles
last. Explain
where in a marsh or lake you would expect to find sand
built up into a
sand bar, and where the fine, muddy sediments would be
deposited.
9. Areas of slow moving water allow more material to
dissolve into
the water. Would you expect more your water sample to
have more
dissolved material than others or less? Why?
10. Streams remove the most where the water moves
fastest: 1) on the
outside of curves, and 2) the middle of the bottom of the
stream in
straight stretches. Sediment is deposited along streams
where they
move slowest: 1) on the inside of curves, and 2) the edges
of straight
stretches. Draw a map of a fictional stream that shows
removal or
deposition in all four places described above.
11. Floods occur when more runoff enters a stream or
river than can
be carried by the main stream channel, and are a normal,
predictable
occurrence along larger streams and rivers. Describe
surface and
weather conditions that will cause this to happen.
12. When a flood occurs, the excess water flows over flat
areas near
the stream called a floodplain. What indicated the flooding
area
along the stream we studied?
13. Sediments are deposited on the floodplain as the
flood water
slows down. What kind of soil is produced by this?
14. The sediments deposited during floods produce the
best soils in
Connecticut. If it was your decision, describe WHY you
WOULD or WOULD
NOT use a piece of flat land along the Farmington or
Naugatuck Rivers
for each of these uses:
Forest:
Schools:
Open space recreation (hiking, picnicking, camping,
fishing):
Recreation fields (baseball, soccer, etc):
Farming:
Houses:
Industrial/commercial uses:
Sewage treatment:
15. Much of the danger of flooding can be prevented by
not allowing
building on the floodplains of rivers and streams. List
three reasons
why society should try to make sure people use floodplains
appropriately.
16. Many of our rivers and streams have been artificially
straightened
and deepened to remove water faster to prevent flooding,
this is
called channelization. This channelization results in
greater
erosion due to faster water, and more flooding and
sedimentation
downstream. Explain why channelization does this.
NAME: PER: DATE:
water sampling technique:
1. Choose container: must be clean (wash with
dishes),
sealable, plastic preferred for carrying to
school.
2. Rinse out with water to be sampled FIVE times.
3. Put container under water to fill - below
surface to avoid
floating debris, but above bottom to avoid
sediments.
4. Bring full container to surface without adding
floating
debris.
5. Close container.
6. Wrap tape around container cover so it is air
tight and so
it does not spill.
7. Record: your name, the name of the body of water
if known,
the location, type of surface water (pond, lake,
stream,
marsh etc), the date, and the length of time
since the last
rainfall.
8. Bring to class on:
Water test instructions:
1) Rinse out beaker with a little sample water.
2) Rinse END of probe with sample water.
3) Fill beaker with sample water.
4) Place tip ONLY of probe into beaker - up to line on
probe.
5) Read and record number from display. Example: 06.
Multiply times
10 for amount of dissolved solids in ppm: 60 parts
per million
means that out of 1 million molecules, 60 were not
water.
6) Rinse off TIP of probe with tap water, pour out
sample water,
rinse out beaker with tap water, toss the container.
7) Enter data into computers.
ENVIRONMENTAL EARTH SCIENCE
RIVERS AND STREAMS VIDEO
During the video "Running Water 1" from Earth
revealed series, take notes on:
1. Factors that affect the ability of a river to remove
and carry
sediment.
2. How streams erode their beds.
3. How rivers carry and deposit sediment.
4. Materials that are carried by rivers.
5. How and where rivers deposit sediment.
6. Features formed by river deposition.
7. Flood causes and effects.
8. Flood plain features, dangers.
9. Effects of dams in rivers.
10. River dynamics (changes) and equilibrium (balance).
11. River management and modeling.
12. Geologic factors that control the behavior of rivers.
13. Other information related to management of rivers.