Running Water

Question 1

Describe the major reservoirs and
transfers of the hydrologic cycle.

Answer 1

Lakes, rivers, and streams evaporate and then precipitate to groundwater and run off back into lakes rivers and streams. Dynamic cycle.

Question 2

Which reservoir in the world is the largest
concentration of all freshwater?

Answer 2

The Great Lakes at 22%

Question 3

What is “headward migration”, why, and
in which direction, is it happening to
Niagara Falls?

Answer 3

When falls move in the upstream direction. Upstream.

Question 4

Be able to calculate the discharge for a
river that is 25 ft. wide, 5 ft. deep, and
which moves at 17 ft/sec. (Answer at the
end of this document.)

Answer 4

2125 ft cubed/sec

Question 5

How does the cross-sectional shape of a
valley differ between those on higher gradient slopes and those on lower gradient slopes?

Question 6

The Mobile River is formed by river
tributaries that drain most of Alabama.
Identify on a map the major rivers of
Alabama.

Answer 6

Question 7

How does the discharge of the Mobile
River compare to the Mississippi River?
the Amazon? the Nile? the Mississippi?

Answer 7

Mobile River - 10,000 to 353,000 ft³/second

Mississippi River - 572,100 ft³/second

Amazon River - 7,733,000 ft³/second(most discharge)

Nile River - 56,000 ft³/second

Question 8

How do “big” rivers (in discharge) get to
be so “big”?

Answer 8

Many tributaries join in V shaped intersections.

Question 9

What are stream “loads”, and in which
part of the river flow do each of these
“loads” move?

Answer 9

Bed load (gravel, sand) -bottom of channel

Suspended load (sand, mud) - well… suspended.

Solution load (Na, Ca, K, …) - dissolved ions that can not be seen.

Question 10

What is stream “competence”, and how is
it measured?

Answer 10

The ability of a stream to carry the biggest boulder.

Question 11

How does the form of the river valley vary
with the slope of the landscape?

Answer 11

V shaped - higher energy

flattened - low energy

Question 12

What are the three processes that
enlarge river valleys? Name, and
describe, using the Grand Canyon, as an
example.

Answer 12

headward erosion lengthens valley.

down-cutting deepens valley.

mass-wasting - widens valley e.g., landslides, etc via weahtering.

Question 13

How do braided and meandering streams
differ? Which of these stream types is
more typical of shallower sloping
landscapes? Steeper landscapes?

Answer 13

braided - sediment loaded (exceeds carrying capacity), multi-channeled, higher slopes. steep landscape

meandering - single-channeled, lower slopes, sinuous in shape pont bars, cut banks. shallow landscape

Question 14

How do “oxbow” lakes form?

Answer 14

Where the river used to run, but has been cut off. Caused by meandering

Question 15

Identify and label parts of a stream and its
floodplain.

Question 16

Describe how sediment are sorted and
deposited in different locations during and
after a flood.

Answer 16

gravel stays in the river, sand is deposited on the banks creating a natural levy, and the mud is carried down into the flood plains.

Question 17

What are “natural levees”, what sediment
typically accumulates there, and how are
they built?

Answer 17

sand, built by floods.

Question 18

What is a “delta” (within the context of
rivers). Where, how, and why does it
form?

Answer 18

When a river gets to sea level and sediment is deposited in a triangular shape. They form because they no longer have a slope.

Sediments enter basin>energy decreases>deposition>transport into deeper water.

Question 19

What are the three types of deltas, and
what forces dominate each type?

Answer 19

wave- wave dominated

classic delta (“birds foot”) dominated by river

Ganges-Brahmaputra delta dominated by current

Question 20

What are progradation and aggradation,
and how do they cause a delta to
change?

Answer 20

progradation is outward

aggradation is upward

Question 21

How has the Mississippi delta changed
the Louisiana coastline during its recent
geological history?

Question 22

What effects on the severity of flooding
are caused by urbanization?

Answer 22

increases obstructions that reate more flooding.

Question 23

What is a hydrograph? What information
does a hydrograph show? How do you
read and interpret values from a
hydrograph?

Question 24

How does a hydroelectric dam produce
electricity? What percentage of our
nation’s electricity is produced by
hydroelectric dams?

Question 25

Why is the Cahaba River National Wildlife
Refuge a protected stretch of the Cahaba
River?

Question 26

What is a watershed?

Question 27

How do family farms and streamside
agribusiness conflict with environmental
issues of rivers and streams?

Question 28

What is the Gulf of Mexico “dead zone”,
and why does it exist?