midterm 3

the equilibrium line occurs on a glacier where the

accumulation rate = ablation rate

a bajada is best described as

coalescing alluvial fans

which of the following flow characteristics is responsible for propagating river meanders

helicoidal flow

what are the SI units of river water discharge often expressed as Q

m³/s

particles that jump along the bed of a steam channel as they are gels in intermittent suspension are being transported by

saltation

the maximum particle size carried by a stream

stream competence

the maximum sediment load of a stream

steam capacity

sort the aquifer horizons from high to low porosity

loose gravel

loose fine grained sand

moderately cemented fine grained sandstone

fractured shale

unfractured shale

what characteristic of water enables frost wedging

water volume expands when it freezes

rivers erode valleys of what shape

V

glaciers wide valleys of what shape

U

true or false: meandering is not just observed in rivers, it is also observed in lava, glacial ice, and even features on mars

true

which of the following are potentially dangerous water supply contaminants

microorganisms

arsenic

radioactive waste

true or false: a meandering river forms when rivers have high sediment loads and unstable, easily erodible channel banks

false

which of the following is a bedrock landform shaped by glacial erosion

roche moutonnee

the actively wording part of a meander bend

cut bank

actively depositing part of a meander bend

point bar

relative humidity is a measure of the amount of water vapor age atmosphere holds as a percentage of

the total amount of water it could hold at the same temperature

how might steam power as expressed by its equation be conserved with distance downstream along a rivers longitudinal profile

as chanel slope decreases discharge increases

what is the ordinary mechanism by which water saturation may induce a landslide

pure pressure counteracts the normal (slope perpendicular) component of gravity

which steam valley may be characterized by a dynamic equilibrium

a valley that is not experiencing net aggradation nor net erosion

x and y axis of a longitudinal profile

x - distance downstream from the river headwaters

y - elevation

which of the following are controls on rock weathering rates

rock structure

precipitation

exposure time

temperature

which type of moraine forms from the merger of two or more lateral moraines

medial moraine

which of the following is not included within the cryosphere

cirrus clouds

what is a reasonable estimate of the angle of repose for dry sand

36 degrees

approximately what fraction of all water on earth is freshwater

4 percent

zone unsaturated with water

vadose

zone saturated with water

phreatic

which of the following is a feature of karst topography

sinkholes

caverns

solution valleys

hot dry winds that descend from a high elevation in the lee side of a rain shadow are called

foehn winds

true or false: melting icebergs and sea ice contribute by themselves to eustatic sea rise

false

sort the following minerals by their chemical weathering rate from fastest to slowest

olivine

pyroxene

biotite

k feldspar

quartz

true or false: the maximum velocity of a stream is near the center of the channel at it just below the surface

true

true or false: a confined aquifer sits at a higher elevation than the regional groundwater table

false

true or false: a slope with a safety factor of 0.6 is safe and stable

false

what type of porosity is characteristic of igneous and metamorphic rock units

fracture porosity

which of the following could induce a shallow landslide

shaking during an earthquake increases the downslope (slope parallel) component of gravity

melting of permafrost saturates soil pore spaces, changing material properties of soil

clear cutting vegetation reduces soil cohesion

precipitation during a hurricane rapidly increases soil pressure

rivers that drain to the ocean

exorheic

robbers that are internally drained to a lake or other basin and do not reach oceans

endorheic

true or false: the hanford nuclear site is a model example of safe radioactive waste disposal and treatment

false

approximately how thick is the greenland ice sheet

thousands of meters