Lecture 2-Hydrology Intro

Question 1

% of water occurring as saline water in oceans

Answer 1

96.5%

Question 2

% of water occurring as freshwater

Answer 2

2.5%

Question 3

% of water occurring as saline groundwater

Answer 3

1%

Question 4

% of FRESHWATER in the cryosphere

Answer 4

68.5%

Question 5

% of FRESHWATER in land reservoirs (lakes, rivers, soil moisture)

Answer 5

1.2%
living things - 0.2%
rivers - 0.5%
swamps - 2.5%
soil moisture - 3.8%
lakes - 20.9%
ice & permafrost - 69%

Question 6

% of FRESHWATER occurring in the atmosphere

Answer 6

3.0%

Question 7

atmosphere water break down (water vapour vs suspended)

Answer 7

water vapour = 99.9%

suspended = 0.0%

Question 8

% of FRESHWATER in groundwater

Answer 8

30.1%

Question 9

key concepts for visualizing the hydrology

Answer 9

cycle
system
continuity (conservation of mass)

Question 10

hydrological cycle

Answer 10

conceptualises the interdependence and continuous movement of all forms of water

Question 11

issues with the hydrological cycle

Answer 11

• implies sequential movement but this isn’t always the case (precip can be evaporated, water can be trapped in groundwater zone)
• missing human element
• water movement is irregular and episodic (rainfall, evap, streamflow)
• limited practical value

Question 12

3 types of human influence
+
examples of consequences of human interference with water cycle

Answer 12

land-use change, climate change, water use change

examples:
diversions, land conversion, deption, contamination, nutrient loading/dead zones, sea-level rise, scarcity, discharge from ice sheets and glaciers, extreme weather from climate change

Question 13

hydrological system (flow chart)

Answer 13

• each catchment/drainage basin is an individual system
• inputs (precip) –> flow routes –> storage –> outputs (evap/runoff)
• each component can be quantified
• components can be ‘sub-systems’
• used to investigate perturbations, feedbacks, external impacts

Question 14

examples of what the hydrological system could be used to study

Answer 14

land-use change, irrigation/land drainage, the abstraction of groundwater or surface water for human use

Question 15

hydrological continuity (conservation of mass)

Answer 15

• hydrological storage and fluxes described by equations
• continuity means: change of storage over time = input - output
• in hydrological context: input=precipication and outputs=evaporation and runoff, so change in storage over time = precipitation - evaporation - runoff

Question 16

calculate global water balance

Answer 16

global annual flux of water between precipitation and evaporation is approximately balanced

Question 17

how is climate change changing the hydrological cycle?

Answer 17

melting from ice - changes in the cryosphere

Question 18

even though it is a very small component, why is the atmosphere important?

Answer 18

Fluxes have a disproportional influence on the whole system because it is the driver of the system, water vapor transfers large masses of water around the planet and occurs in short time frames

Question 19

rivers are also a small percentage, why are rivers important?

Answer 19

generally renewable, transports water between places, source to supply, water from rivers is easy for us to utilize

Question 20

global water balance / hydrological cycle simplified description

Answer 20

precipitation (373) and evaporation (413) occur over the ocean, the difference (40) is water vapor that gets transferred over the land. Then over land precip (113) and evap (73) also occur. The remaining (>40) gets stored or becomes runoff (> because of melting from ice)

Question 21

how to convert volume into a depth

Answer 21

divide by the area

Question 22

water deficit

Answer 22

more water loss (evaporation) than input (precipitation)

Question 23

water surplus

Answer 23

more input (precipitation) than water loss (evaporation) so surplus is water runoff

Question 24

describe the water balance for tropical rainforest

Answer 24

high rainfall
input > 2000 mm

balance: some of the precipitation will be balanced by evapotranspiration, but there will be large runoff values

Question 25

describe the water balance for sub-tropical hot desert

Answer 25

low precipitation
input < 250 mm (but can be much lower)

balance: high evaporation, very low runoff (typically ephemeral streams), will see more water stored in the ground which may be very old

Question 26

describe the water balance for the high latitude (polar) region

Answer 26

precipitation relatively low
input around 300 mm (and a lot will occur as snow which changes dynamics of the system downstream)

balance: seasonal, snowmelt releases water to join the catchment, evaporation is low - not much water (or vegetation) because it is locked up in the snow, sublimation can occur