Topic 5: Surface Water

Question 1

what does surface water include?

Answer 1

streams
lakes
glaciers
snow
soil water
vegetation
wetlands

Question 2

what percentage of Canada does freshwater make up?

Answer 2

8.9% or 891,163km^2

Question 3

gravity force in water flow

Answer 3

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

Question 4

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

Answer 4

middle

Question 5

name the 4 types of water flow

Answer 5

laminar
turbulent
steady
unsteady

Question 6

which three things does Froude number use?

Answer 6

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

Question 7

name and explain the three types of Froude flow

Answer 7

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

Question 8

what causes river velocity to change?

Answer 8

stage and discharge

Question 9

define stage and discharge

Answer 9

stage= water level

discharge is a function of stage

Question 10

how do you measure stage

Answer 10

using the building with the float and counterweight

Question 11

how can you measure discharge

Answer 11

velocity area method

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

Question 12

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

Answer 12

true

Question 13

quickflow vs baseflow

Answer 13

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.

Question 14

perennial vs ephemeral streams

Answer 14

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).

Question 15

hydrograph characteristics depend on what

Answer 15

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

Question 16

what is a unit hydrograph used for

Answer 16

to predict discharge/floods

Question 17

describe overland flow and what influences it

Answer 17

non-channeled water flow over the ground surface.

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

Question 18

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

Answer 18

infiltration excess overland flow

saturation excess overland flow

Question 19

describe infiltration excess overland flow

Answer 19

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)

Question 20

explain saturation excess overland flow

Answer 20

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

Question 21

define flooding

Answer 21

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

Question 22

what does bankfull mean

Answer 22

threshold stage before river flows over banks

Question 23

how to predict floods

Answer 23

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

Question 24

facts about flooding in N. America

Answer 24

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.

Question 25

what is a wetland

Answer 25

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.

Question 26

define a marsh

Answer 26

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

Question 27

define swamp

Answer 27

woody plants, often treed, deeper water, nutrient rich

Question 28

describe a bog

Answer 28

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

Question 29

describe a fens

Answer 29

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

Question 30

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

Answer 30

indonesia

Question 31

which country has the highest peat carbon stock

Answer 31

Canada

Question 32

which covers more in Canada: peatlands or wetlands?

Answer 32

wetlands cover 14% peatlands cover 12%

Question 33

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

Answer 33

Lake Baikal

Question 34

other term for Pineapple Express or Tropical Punch

Answer 34

Atmospheric River

Question 35

what is an atmospheric river

Answer 35

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

Question 36

atmospheric river characteristics

Answer 36

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

Question 37

explain rain on snow events

Answer 37

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

Question 38

Atmospheric rivers and climate change

Answer 38

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