Water Hydrology and Streams Flashcards

1
Q

Hydrologic cycle

A

movement of water between hydrosphere (ocean), atmosphere (air), and lithosphere (land)

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2
Q

Hydrologic processes (5 points)

A
  • Evaporation
  • precipitation
  • infiltration
  • evapotranspiration
  • runoff (streams)
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3
Q

runofff

A

part of precipitation that does not infiltrate or re-evaporate, that is collected by stream.

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4
Q

Annual water balance

A

-stream runoff (mm/annum)= imput-losses
(imput=rain and snow, losses=evapotranspiration)
-storage (changes in volume of soil, or lake/river water

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5
Q

steady state

A

imput=output

no increase in reservoir size

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6
Q

Residence time

A

volume/imput

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7
Q

1 km^2= xm^2?

A

1 km^2 = 1*10^6 m^2

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8
Q

Examples f residence times:

A

H2O in atmosphere: A few days
H2O in lake ON: 6.4-9 yrs
Ground H2O in deep aquifer: 100s-1000s of yrs
Sea water in ocean: ~3200 yrs

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9
Q

What happens when imput is greater than output? (2 points)

A
  • flooding

- ships can carry more cargo without grounding

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10
Q

What happens when loss is greater than precipitation imput? (5 points)

A
  • drop in water levele
  • increase in salinity
  • soil dries up
  • wind born soil transport increases
  • agricultural failure
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11
Q

Define stream

A
  • any flowing body of water

- most important eroding agent and main function of sediment transport

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12
Q

Define river

A

major branch of a stream system

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13
Q

Importance of streams

A
  • major agents of change in landscapes
  • provided pathways for colonists
  • most cities are buit around a river (source of drinking water)
  • agriculture
  • recreation
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14
Q

Stream System components

A
  • Drainage basin
  • tributary
  • drainage divide
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15
Q

Drainage Basin

A

total area drained by stream and its tributaries

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16
Q

Tributaries

A

Small stream flowing into larger (small stream conTRIBUTES to larger)

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17
Q

Drainage divide

A

ridge of high ground dividing one drainage basin from another

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18
Q

Largest Drainage basins in North America?

A

1) Mississippi (3.2 million km2)

2) Mackenzie (1.8 million km2)

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19
Q

Largest Drain Basin globally?

A

The Amazon river (6 million km2)

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20
Q

Define headwaters and mouth

A
  • headwaters=source

- mouth is where river enters open water

21
Q

Stream system components

A
  • Valleys: sloping area around stream
  • channel: bottom of valley where water flows
  • floodplains: flat area in valley level with top of channel. (can be flooded)
22
Q

Define Gradient (L)

A

change in height/distance (cm-m/km)

-decreases as you go downstream

23
Q

Define Discharge (Q) (m3/s)

A

=velocity (U) (m/s)/area (m2)

-increases downstream due to collection from tributaries

24
Q

Depth (d) and Width (w)

A

channel size INCREASES downstream

-increased area (A)= decresed friction; larger streams have greater velocity (U)

25
Q

velocity (U) (m/s)

A

U increases downstream; less bed roughness, higher Q, larger channels

26
Q

What is the purpose of a stream?

A

plane out relief via channelized flow (most efficient)

27
Q

How does a stream plane out relief via channelized flow? (3 things)

A

1) erosion
2) transport
3) deposition

28
Q

What controls erosion, transport, and and deposition? (3 things)

A

1) hydraulic parameters:
-flow velocity, discharge, viscosity
(volume of water flowing through channel and the velocity at which it does so)
2) morphology
(ie. Fast flowing cascade in mountains vs long, sinuous river in plains
3) material (that its eroding into or transporting)
(ie. eroding into granit vs loose sediment; transporting large boulders vs sand)

29
Q

modes of sediment transport (4)

A
  • Bedload (along the bed)
  • Saltation (periodically lifts off into flow)
  • suspension (in the flow)
  • solution (dissolved in flow)
30
Q

True or False: Grain size transported by stream is directly proportional to stream velocity

A

true

31
Q

What law describes the forces of buoyancy and friction (drag due to flow)

A

Stoke’s Law

32
Q

True or False, particles settle when F(gravity)>(Fbuoy+Fdrag)

A

true

33
Q

F(gravity)

A

=m(particle)*g

=Volume(particle)Density(particle)g

34
Q

Fluid Buoyancy Force

A

=Volume(p)Density(p)g

35
Q

Force G-B

A

=V(p)(D(p)-D(f))g

36
Q

Fluid Drag Force

A

Drag=0.5CD(fluid)R(p)^2*W^2

C is a drag coefficient, R(p) is particle radius, W is water velocity, and D(f) is fluid density

37
Q

Base level

A
  • level below which stream cannot erode.

- changes in base level result in changes in the longitudinal profile

38
Q

Graded stream

A

equilibrium state where stream can transport its load without deposition or erosion

39
Q

What happens to longitudinal profile following an increase in base level?

A

increase in deposition

40
Q

What happens to longitudinal profile following a decrease in base level?

A
  • increased erosion

- increased transport

41
Q

Channel patterns

A

1) braided

2) meandering

42
Q

Braided rivers

A
  • rapid and irregular discharge
  • higher slopes
  • erodible banks
  • rapid channel migration
  • abundant coarse sediment
  • in-channel bars (lense of sediment)
  • little overbank preservation
  • poorly developed levees
  • lateral accretion deposits uncommon
43
Q

Meandering Rivers

A
  • lower and more regular discharge
  • lower slopes
  • cohesive banks (less likely to erode)
  • slower, more regular channel migration
  • abundant fine sediment
  • extensive overbank preservation
  • well developed levees
  • few inchannel bars
  • lateral accretion deposits common
44
Q

What is a consequence of secondary flow?

A

point bars (deposits along inner bank

45
Q

helicoidal flow

A

response to secondary flow (cross channel flow) pressure gradient established by pile up of water in outer bank from centrifugal force and downstream flow

46
Q

Causes of floods (3)

A

1) high precipitation over short amount of time
2) ice jam
3) dam and artificial levees

47
Q

Factors contributing to floods (2)

A

1) low infiltration rate (bedrock, saturated soil, frozen ground, cities)=high runoff rate
2) topography (flat area, funnelling effect)

48
Q

Impacts of flooding (3 main points)

A

Human consequences

  • loss of life
  • disease
  • water contamination

Material impact
-destruction or damage to property and infrastructures

Landscape

  • erosion (high discharge)
  • sedimentation (reduced velocity–>channel invades floodplain)
  • avulsion (abandonment of old channel for new one)
49
Q

Flood controls (5 things)

A
  • artificial levees (must be continually built up as river deposits more due to inability to flood)
  • dams
  • channelization
  • natural storage areas
  • live elsewhere