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31 Cards in this Set
- Front
- Back
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What is mass movement, or mass wasting?
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the transport of material downslope due to gravity; an exceeding of the angle of repose
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What is the angle of repose?
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the maximum angle before material starts to collapse, usually around 30-35 degrees
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What five factors affect mass movement (wasting)?
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slope, water, material, vegetation/humans (+/-), and seismic activity
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Name and explain the two types of mass movement (wasting).
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Slow- creep
-slow, imperceptible movements (gravestones) Fast- slides (rock, mud) and flows (liquid medium) mud flows at volcanic eruption |
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What is the global water budget?
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97.2% of water in the ocean
2.15% in ice about .65% in groundwater, streams, lakes, and atmosphere |
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Where did the earth's water come from?
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Water came from volcanoes and comets/meteorites.
Approximately 1/3 of earth's water came from comets. |
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What is a stream?
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Water confined to a channel
Also known as rivers, creeks, bayous, runs, etc. Create low points on a map |
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What are flood plains?
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areas where water occassionally flows over a channel
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What is a drainage basin?
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An area that collects water
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What is a divide?
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Separates drainage basins
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What is a continental divide?
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A large divide that determines whether water flows east or west
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What two factors determine stream flow and discharge?
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Gradient (slope) of stream bottom, and velocity (distance that stream's water travels over a given length of time
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What is considered a slow moving stream?
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1 ft/sec
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What is considered a fast moving stream?
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33 ft/sec
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What is stream discharge?
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The volume of water passing a point over a given period of time
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How do you calculate stream discharge?
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(Velocity x Cross-sectional area) / min
Cross-sectional area= width x depth |
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What are the three transports of sediments (loads)?
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Dissolved load
Suspended load Bed load |
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What is dissolved load?
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averages about 120 parts per million (ppm)
10-15% of total load (dissolved material) |
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What is a suspended load?
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largest load
affected by velocity load=square of velocity (V/1=L/1, V/2=L/4) if load exceeds velocity, it will float in the water column |
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What is bed load?
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rolling, sliding, saltation (crash, 'jump' into the air)
minor, except in mountain streams |
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What is a levee?
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a natural barrier on the edge of a stream
(energy leaves, sediment is deposited) |
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What are flood predictions based upon?
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Recurrency (10 years, 50 years, 100 years, etc)
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What is a water table?
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The boundary between the zone of aeration and zone of saturation
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How fast does ground water move?
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a few inches per week
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How are streams fed?
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By seeps and springs (groundwater)
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What is porosity?
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pore space ("holes") in material
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What is an aquifer?
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Material able to hold and transmit water
e.g. gravel and sand |
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What is an aquitard?
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Material is impermeable
e.g. clay, limestone (unfractured) |
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What is permeability?
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The ability of a medium to transmit a fluid
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What is an artesian system?
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An aquifer that is between two aquitards. The pressure causes the water to flow freely; it doesn't need to be pumped.
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Where does water get into an aquifer?
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Recharge area (water quality is a function of this)
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