Test 3

Geography
hydrological cycle
the path water takes in our environment etiher through ground, plants, or atmostphere
hydrologic cycle can occur in ground by…
evaporation from soil, ground water, runoff
hydrology
the study of water
paths water can take from plants:
transpiration Animals: Respiration + perspiration (evapotranspiration)
path water cantake in the atmosphere:(3)
evaporation, precipitation, clouds
Global water Budjets:
Oceans.. %
Icecaps/glaciers..
ground and soil water..
rivers and lakes..
atmosphere..
oceans 97.6
icecaps/galciers 1.9
ground and soil water .5
rivers and alkes .02
atmosphere .0001
Run off and stream flows
storage in:
soil and/or ground water
an aquifer is a:
an underground rock layer that holds water (not an underground lake)
Runoff+
precipitations- evapotranspiration +/- change in storage runn off is the movement of water over the surface of the land
run off goes into…
streams and rivers
discharge is…
the amount of runoff that goes into river and streams
Formula for discharge?
cross-sectional area of stream X mean velocity of stream. 1mph is about 1.5 foot/sec
river flows at 30mph. depth is 5ft. width is 10 frt. what is the discharge?
5X10=50
velocity= 30X1.5= 45
45X50= 225cfs
discharge depends on gradient
the larger the gradient the ____ the discharge
larger
drainage basin
land area that contriubtes runoff to river system
drainage divide:
boundary between drainage basins (the higher the elevation)
explain the stream networkstream of 1st order
stream of 2nd order
stream of 3rd order
the system of the main river channel plus its tributaries (heiarchial ranking system)
1st- no tributaries
2nd- merging or joining of two 1st order streams
3rd- merging of two 2nd order streams
when2 streams of same order merge the merged streams will be one order..(higher/lower)
higher
when 2 sreams of different order merge the merged stram will be the same order as (higher/lower) stream
higher
baseflow:
ground water runoff released over large periods of time (the avg. flow of a stream)
stormflow:
overland flow (the extra water running off land from a storm)
stream hydrograph:
plot flow against time
what influences the shape of hydrography?
a. size of basin
b. type of surface
c. shape of watershed
d. slope
e. intensity and duration of rain
f. urbanization
whats urbanization?
pavement and concrete are impermeable to water so water must flow across surface
urban flood occur faster after the rain and are bigger in magnitude than ruralfloods
true
fluvial landforms are
landform created by running WATER
-fluvial processes have done more to shape our earth than any other process
Erosion is
the wearing away of land and soil through the process of running water (ex. gully and arroyos)
deposition is
the placement of the material carried by running water (ex. deltas)
splash erosion is..
direct force of falling drops on base soil causing a geyserlike splashing in which soil particles are liften and then dropped into new positions
accelerated erosion:
the removal of soil much faster than it can be formed (overgrazing, forest fires remove vegetation and erosion starts)
ex- badlands (in s. dakota and colorado)
badlands are underlain by ____which do not allow water to seep through therefore the water must go as runoff and it erodes the surface features.
clay formations
what are the 3 mechanisms of stream geology?
stream erosion
stream transporation
stream deposition
stream erosion
removal of material from the floor andsides of a channel
stream transporation:
movemeent of the eroded particles
thru…
suspension (material help up by water)
dissolved(mixed with the water (salt))
bed load: sand, gravel and cobbles move by rolling or sliding from water flow
Stream deposition: depositing the material carried by the stream:occurs when there is a major change in stream discharge.
saltration:
bouncing or skipping along stream bed
traction:
rolling or sliding
stream gradiation:
the slow reduction in the height of the headwater of a stream through time as the stream eroded away the surrounding materials there are 4 steps
what are william morris davis’s 4 steps of stream gradiation?
1.stream established on land recently uplifted
2. gradiation in grogres (lake draining and deepening gorge
3.graded profile attained. beginning of floodplain. valley widening
4. flood plain widened to hold meanders

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