Running Water Flashcards
Describe the major reservoirs and
transfers of the hydrologic cycle.
Lakes, rivers, and streams evaporate and then precipitate to groundwater and run off back into lakes rivers and streams. Dynamic cycle.
Which reservoir in the world is the largest
concentration of all freshwater?
The Great Lakes at 22%
What is “headward migration”, why, and
in which direction, is it happening to
Niagara Falls?
When falls move in the upstream direction. Upstream.
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.)
2125 ft cubed/sec
How does the cross-sectional shape of a
valley differ between those on higher gradient slopes and those on lower gradient slopes?
The Mobile River is formed by river
tributaries that drain most of Alabama.
Identify on a map the major rivers of
Alabama.
How does the discharge of the Mobile
River compare to the Mississippi River?
the Amazon? the Nile? the Mississippi?
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
How do “big” rivers (in discharge) get to
be so “big”?
Many tributaries join in V shaped intersections.
What are stream “loads”, and in which
part of the river flow do each of these
“loads” move?
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.
What is stream “competence”, and how is
it measured?
The ability of a stream to carry the biggest boulder.
How does the form of the river valley vary
with the slope of the landscape?
V shaped - higher energy
flattened - low energy
What are the three processes that
enlarge river valleys? Name, and
describe, using the Grand Canyon, as an
example.
headward erosion lengthens valley.
down-cutting deepens valley.
mass-wasting - widens valley e.g., landslides, etc via weahtering.
How do braided and meandering streams
differ? Which of these stream types is
more typical of shallower sloping
landscapes? Steeper landscapes?
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
How do “oxbow” lakes form?
Where the river used to run, but has been cut off. Caused by meandering
Identify and label parts of a stream and its
floodplain.
Describe how sediment are sorted and
deposited in different locations during and
after a flood.
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.
What are “natural levees”, what sediment
typically accumulates there, and how are
they built?
sand, built by floods.
What is a “delta” (within the context of
rivers). Where, how, and why does it
form?
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.
What are the three types of deltas, and
what forces dominate each type?
wave- wave dominated
classic delta (“birds foot”) dominated by river
Ganges-Brahmaputra delta dominated by current
What are progradation and aggradation,
and how do they cause a delta to
change?
progradation is outward
aggradation is upward
How has the Mississippi delta changed
the Louisiana coastline during its recent
geological history?
What effects on the severity of flooding
are caused by urbanization?
increases obstructions that reate more flooding.
What is a hydrograph? What information
does a hydrograph show? How do you
read and interpret values from a
hydrograph?
How does a hydroelectric dam produce
electricity? What percentage of our
nation’s electricity is produced by
hydroelectric dams?
Why is the Cahaba River National Wildlife
Refuge a protected stretch of the Cahaba
River?
What is a watershed?
How do family farms and streamside
agribusiness conflict with environmental
issues of rivers and streams?
What is the Gulf of Mexico “dead zone”,
and why does it exist?
