Exam 1 Flashcards

1
Q

Modern Hydrology

A

the dist of water on Earth’s surface and the movement of water (under/over surface and throughout atmosphere)

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2
Q

Hydrologist

A

primary focus is fresh water

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3
Q

Water Distribution %s

A

Oceans: 96.8%
Freshwater: 3.2% (ice=75%; GW=25%) lakes: 0.3; Biosphere: 0.24; soil: 0.06; clouds: 0.03; rivers: 0.003

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4
Q

Amount of freshwater available for use:

A

0.3%

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5
Q

Water demand growth per year

A

60 billion cubic m/year

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6
Q

water stressed defiition

A

any country with less than 1700 cubic m/person

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7
Q

% people water stressed by 2030

A

47%

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8
Q

% population at risk of water shortages

A

80%

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9
Q

Global use of water

A

world avg (ag: 70%; industry: 22%; Domestic: 8%)

Low/middle income countries (ag: 82%; Industrial: 10%; domestic: 8%)

High income countries (industrial: 59%; ag: 30%; domestic 11%)

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10
Q

Water Budget Equation

A

in flow - outflow = chg storage

P + E + Q + chg S = 0

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11
Q

Precipitation

A

the release of water from the atmosphere to the surface of the Earth
(expressed as vertical depth)

happens when atmosphere is saturated, small particles present (dust)
water/ice particles large enough to reach earth against updrafts

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12
Q

Boyle’s Law:

A

P = 1/V

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13
Q

If temp cools:

A

there is less ability of air to hold moisture (condensation: dew/frost)

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14
Q

Convective precipitation definition

A

uplift caused by heating of the Earth’s surface

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15
Q

Orographic precipitation definition

A

air mass is forced to rise over an obstruction (ex: mountain range)

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16
Q

Frontal/ cyclonic precipitation definition

A

a low pressure weather system where air is constantly being forced upwards

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17
Q

Cloud seeding definition

A

purposefully putting particles of some sort in the air to entice precipitation to occur

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18
Q

Collision coalescence definition

A

droplets grow as they collide with other smaller droplets as they fall -pressure will often lift them again until they have enough mass (usually in warm clouds abt 5F)

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19
Q

Bergeron Process definition

A

a process of ice crystal growths in clouds containing a mixture of supercooled water (abt -40F) and ice when ambient vapor pressure falls between the saturation vapor pressure over water and the lower saturation vapor pressure of ice.

Since ice has less vapor pressure than the supercooled water and water vapor, the water will connect to the ice particles, increasing their size. This often results in precipitation.

(large particles grow at expense of small)
-most common at mid - high latitudes

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20
Q

Dewfall definition

A

dew forms as temps drop and objects cool down - if cool enough, will also cool air, making it less able to hold the vapor, so the water vapor condenses into dew

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21
Q

Static influences on precipitation distribution

A

geography, altitude, aspect, and slope

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22
Q

rain shadow definition

A

when the geographical differences in rainfall in two adjacent regions are very visible (ex: forested mountains vs desert valley)

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23
Q

Rainfall measurement errors

A

instrumentation and sampling errors

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24
Q

Wetting loss definition

A

water that stays on the surface of the tunnel and is lost to evaporation

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25
Q

deciding how many rain gauges are needed

A

the number of gauges will increase with the size of the watershed

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26
Q

Arithmetic mean

A

taking average of all gauge estimates

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27
Q

Theissen’s polygons

A

weighed average of what areas are most impacted by the rain (split into ranges)
ex: 30% of watershed had 2 in rain

28
Q

Hypsometric Method

A

similar elevations get averaged together (topography)

29
Q

Isohytel

A

find similar places and group them

30
Q

Evaporation definition

A

the transfer of liquid into a gaseous state

31
Q

Evapotranspiration definition

A

evap from soils, water, plant interception, and transpiration

32
Q

Transpiration definition

A

when the plant roots absorb water, it goes to leaves which then increases to solute conc. This creates an “osmotic pressure gradient” so the stomata open to relieve pressure. The water is evaporated out of the stomata.

(70% of precip)

33
Q

Evapotranspiration formula

A

ET = P - Q - chg S - chg l (deep storage)

34
Q

Net Radiation

A

measure of the amount of energy received at the surface (Q)

35
Q

Vapor flow

A

a water molecule moves from a higher conc to lower conc.

Vapor pressure at evap surface than receiving atmosphere: this pressure is largely controlled by temp

36
Q

Factors affecting interception

A
  • intensity of precipitation
  • wind velocity
  • Evap demand after rainfall
  • leaf type
  • leaf and branch SA
37
Q

Interception definition

A

when water is stopped from going to ground by trees and other obstructions

38
Q

Throughfall definition

A

the water that falls in between obstructions like trees to the ground

39
Q

Stem flow definition

A

water that runs down the trunks and stems of trees and plants (< 2%)

40
Q

Net Precipitation

A

amount of precipitation available for surface ground water

41
Q

Gross precipitation

A

total precipitation minus that lost by evaporation

42
Q

what trees have highest interception

A

conifers (more SA)

43
Q

Of grasslands, bare soils, and forests: which have highest evaporation rates?

A

Forests at 20-40% interception
grasslands intercept 10-20%
(but it still depends on exact type of ecosystem ex: mixed hardwood vs conifers)

44
Q

Direct micro-meteorological measurement devices

A

Anemometers
Eddy
Aerodynamic
Bowen ratio

45
Q

Indirect micro-meteorological measurement devices

A

Evaporation pans

Lysimeters

46
Q

Eddy

A

measures water vapor increases on the surface with vertical wind speed and temperature

Requires an anemometer

47
Q

Aerodynamic Profile Method

A

calculates the amount of energy available for evaporation to determine actual evap rate

48
Q

Bowen Ratio

A

similar to the Aerodynamic method but does not assume variations

49
Q

Evaporation Pans

A

measuring amount of evaporation (easy and cheap method)

50
Q

Lysimeter

A

complex versions of evaporation pans (giant buckets on scales)
-can grow grass to imitate surface evaporation

51
Q

problems with evaporation pans

A
  • open water measurements- sig higher than normaql evap

- edge effect (will warm up faster)

52
Q

Role of Forest litter in interception

A
  • can store part or all of throughfall
  • storage capacity can be great (depending on litter type)
  • Moisture content is generally high
53
Q

What does Q stand for?

A

Streamflow

54
Q

Relationship between evaporation and pressure

A

Inverse

55
Q

Infiltration capacity

A

maximum rate that water can enter the soil

56
Q

Infiltration rate

A

instantaneous rate at which water enters the soil

57
Q

Soil water

A

amount of water contained within the soil

58
Q

infiltration

A

process of water entering the surface of the soil

59
Q

percolation

A

process of water movement through the soil

60
Q

Is pore size, capillary action, or gravity NOT responsible for infiltration of water

A

pore size

61
Q

the gravitimetric method is most similar to what soil expression

A

Oven-dry water content

62
Q

T or F: highly porous soil reaches the wilting point fastest given a relatively low depth of water per depth of soil

A

True

63
Q

T or F: Field capacity is related high soil water tension

A

True

64
Q

Dangers of limited water access

A

Diarrhea, typhoid, cholera, malaria

65
Q

3 Types of Uplift

A

Convective, Orographic, and frontal/cyclonic

66
Q

Temp for collison coalescence

A

Around 5 degrees F

67
Q

Temp for Bergeron Process

A

Around -40 degrees F