Topic 5: Surface Water Flashcards

1
Q

what does surface water include?

A
streams
lakes
glaciers
snow
soil water
vegetation
wetlands
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2
Q

what percentage of Canada does freshwater make up?

A

8.9% or 891,163km^2

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3
Q

gravity force in water flow

A

moves water down rivers and drives a conversion from potential energy to kinetic energy

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4
Q

where is flow highest in a stream cross section (bank, or middle)

A

middle

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5
Q

name the 4 types of water flow

A

laminar
turbulent
steady
unsteady

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6
Q

which three things does Froude number use?

A
v= flow velocity
vw= surface wave velocity
H= water depth (height)
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7
Q

name and explain the three types of Froude flow

A
  1. subcritical turbulent flow where velocity is less than wave velocity Fr<1
  2. Critical flow where flow velocity equals wave velocity Fr=1
  3. Supercritical laminar flow where flow velocity s greater than wave velocity and Fr>1
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8
Q

what causes river velocity to change?

A

stage and discharge

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9
Q

define stage and discharge

A

stage= water level

discharge is a function of stage

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10
Q

how do you measure stage

A

using the building with the float and counterweight

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11
Q

how can you measure discharge

A

velocity area method

Q=A x V or (W x D)xV

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12
Q

T or F: discharge increases with an increase in depth, width or velocity?

A

true

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13
Q

quickflow vs baseflow

A

base flow doesn’t respond from large rain events, sources from groundwater vs quick flow responds to precip. events and rapidly delivers water to streams.

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14
Q

perennial vs ephemeral streams

A

Perennial stream has continuous flow in stream bed all year round (Cowichan river)

Ephemeral: channels that flow for hours or days following rainfall or snow melt (3rd, 4th 5th order streams).

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15
Q

hydrograph characteristics depend on what

A
precipitation (magnitude, intensity, duration, distribution)
basin characteristics (slope angle, soil type, soil thickness, initial moisture conditions, basin size and shape)
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16
Q

what is a unit hydrograph used for

A

to predict discharge/floods

17
Q

describe overland flow and what influences it

A

non-channeled water flow over the ground surface.

  • precip intensity
  • snow melt rate
  • pre-existing soil saturation level
  • ground cover
  • soil type
  • topography
18
Q

name the two types of surface runoff from rain or snow melt

A

infiltration excess overland flow

saturation excess overland flow

19
Q

describe infiltration excess overland flow

A

occurs with soil that is not saturated, soil properties or land cover do not allow for infiltration to keep up with high rainfall or snowmelt rates. (Hortonian Flow)

20
Q

explain saturation excess overland flow

A

occurs when the soil becomes saturated and no longer space for water to infiltrate

21
Q

define flooding

A

rising stage level associated with excess discharge in response to storms of seasonal melt. it is a natural process required to maintain river form and function. defied by channel cross-section and bank height

22
Q

what does bankfull mean

A

threshold stage before river flows over banks

23
Q

how to predict floods

A
  1. hydrograph
  2. recurrence interval (R) which is the annual peak discharge records used to predict flood probability (P)
  3. rational method which estimates peak annual discharge using empirical formulae and data on rainfall ad basin stats
24
Q

facts about flooding in N. America

A
  1. rates of urban growth in floodplains is 2x of other areas
  2. BC experiences the largest floods in N. America from high intensity precip with rapid mountain runoff.
25
Q

what is a wetland

A

land where and excess of water is the dominant factor determining the nature of soil development and types of animals and plants living at soil surface.

26
Q

define a marsh

A

wet most of the time; grassy / reedy vegetation can be salty or fresh most common wetland in N. America

27
Q

define swamp

A

woody plants, often treed, deeper water, nutrient rich

28
Q

describe a bog

A

water from precipitation mostly thick mat of vegetation rather than soil, often acidic, soft spongy organic

29
Q

describe a fens

A

like a bog but fed more from surface or groundwater, more nutrients, higher pH. associated with glacial kettles

30
Q

which country has the largest emissions from degrading peat, carbon dioxide?

A

indonesia

31
Q

which country has the highest peat carbon stock

A

Canada

32
Q

which covers more in Canada: peatlands or wetlands?

A

wetlands cover 14% peatlands cover 12%

33
Q

which lake holds 20% of the worlds lake water and is estimated 25-30Ma

A

Lake Baikal

34
Q

other term for Pineapple Express or Tropical Punch

A

Atmospheric River

35
Q

what is an atmospheric river

A

giant bands of water vapour on average 800km wide and several hundred km long.

36
Q

atmospheric river characteristics

A

extremely moist- high precipitation rates
can have several events or episodes
season is september to march
20-25% annual precip comes from AR

37
Q

explain rain on snow events

A

when there is an increase in temperature and freezing levels >1500m

38
Q

Atmospheric rivers and climate change

A

more frequent precip events
shift poleward of mid latitude storms
increase in strength of most tropical storms
expansion of the moist tropic zone from which AR draw moisture