Water Cycle & Insecurity

Question 1

What are the three concepts that are key to how water cycling operates?

Answer 1

Stores, Fluxes, and Processes

Question 2

What is the difference between blue and green water?

Answer 2

Blue water is stored in liquid form (the visible part of the hydrological cycle), and green water is stored in soil & vegetation (invisible part of the hydrological cycle)

Question 3

What is the residence time for the following global water stores:
Oceans:
Icecaps:
Groundwater:
Rivers & Lakes:
Soil Moisture:
Atmospheric Moisture:

Answer 3

Oceans: 3,600 years
Icecaps: 15,000 years depending on size
Groundwater: 100-200 years for shallow groundwater, up to 10,000 for deep groundwater.
Rivers & Lakes: 2 week to 10 years; 50 years for every large cycle.
Soil Moisture: 2-50 weeks
Atmospheric Moisture: 10 days

Question 4

What are the main processes that drive fluxes in the hydrological cycle?

Answer 4

Precipitation
Evaporation
Cryosphere Exchange
Run-Off generation

Question 5

What percent of global water do each of the following stores hold, and also what percentage of fresh water:
Oceans:
Icecaps:
Groundwater
Rivers & Lakes:
Soil Moisture:
Atmospheric Moisture:

Answer 5

Oceans: 96.9% (0% of all freshwater)
Icecaps: 1.9% (68.7% of all freshwater)
Groundwater: 1.1% (30.1% of all freshwater)
Rivers & Lakes: 0.01% (1.2% of all freshwater)
Soil Moisture: 0.01% (0.05% of all freshwater)
Atmospheric Moisture: 0.001% (0.04% of all freshwater)

Question 6

What is fossil water?

Answer 6

Ancient deep groundwater from former pluvial (wetter) periods, often not accessible for humans.

Question 7

Catchment

Answer 7

The area of land drained by a river and its tributaries

Question 8

Watershed

Answer 8

The high land which divides and separates water flowing to different rivers

Question 9

Condensation

Answer 9

The change from a gas to liquid, such as when water vapour changes into water droplets.

Question 10

Dew Point

Answer 10

The temperature at which dew forms; it is a measure of atmospheric moisture.

Question 11

Name the inputs and outputs of a drainage basin

Answer 11

Inputs:
1. Precipitation

Outputs:
1. Evaporation and transpiration from vegetation.
2. Evaporation from water body surfaces.
3. River Discharge.

Question 12

Define an open system

Answer 12

Any system which has inputs and outputs.

Question 13

Define transpiration

Answer 13

The evaporation of water from vegetation (outputted).

Question 14

Define interception

Answer 14

Precipitation that does not reach the soil (may land of vegetation)

Question 15

Define Stem Flow

Answer 15

The flow of intercepted water down the trunk or stem of a plant.

Question 16

Define Carrying Capacity

Answer 16

The amount of water that can be held e.g. in soil.

Question 17

Define Surface Runoff

Answer 17

Precipitation that runs down the surface.

Question 18

Define Tributary

Answer 18

a stream that feeds into a larger stream or river

Question 19

Define Infiltration

Answer 19

the process of water moving through soil and rock layers that make up the Earth’s surface

Question 20

Define throughflow

Answer 20

The lateral unsaturated flow of water in the soil zone, typically through a highly permeable area.

Question 21

Define what a Water Table is

Answer 21

An underground boundary between the soil surface and the area where groundwater saturates spaces between sediments and cracks in rock

Question 22

Define what the aeration zone is

Answer 22

The subsurface zone between the ground surface and the water table, where the pores in soil and rock contain both air and water

Question 23

Define Percolation

Answer 23

the movement of water through the soil downwards.

Question 24

Define Ground Water flow

Answer 24

water movement that exists underground in saturated zones beneath the watershed (slow)

Question 25

Define an aquifer

Answer 25

A body of rock and/or sediment that holds groundwater

Question 26

Define Base Flow

Answer 26

A portion of the stream flow that is not runoff; it is water from the ground, flowing into the channel over a long time and with a certain delay

Question 27

Define a flux

Answer 27

The rate of flow between the stores

Question 28

Define a store

Answer 28

reservoirs where water is held, such as the oceans.

Question 29

Define a process

Answer 29

The physical mechanisms which drive the fluxes of water between the stores.

Question 30

What are the three types of rainfall?

Answer 30

1. Conventional Rainfall.
2. Frontal / Cyclonic Rainfall.
3. Orographic Rainfall.

Question 31

Define what the windward and leeward side are

Answer 31

The leeward side is the slope downwards after mass precipitation on the other side (receives relative little rain). The windward side receives more rainfall as the orographic clouds rise to then dump their precipitation.

Question 32

Explain Frontal / Cyclonic Rainfall

Answer 32

Warm air front rises against cooler front. The ability for rising air the cools to carry water decreases, allowing the condensation to occur which forms cumulus clouds that will eventually precipitate.

Question 33

Define Convectional Rainfall

Answer 33

Common in tropical areas. When land becomes hot, the air above becomes warmer, expands, and rises. This air then cools and its ability to hold water vapour decreases to make cumulous clouds that often create short bursts of heavy rainfall.

Question 34

Define Orographic rainfall

Answer 34

When air is forced to rise over a barrier (e.g. mountains), it cools and condensation takes place forming rain.

Question 35

Rain Shadow

Answer 35

The dry area on a leeward (downward) side of the mountain. It receives little rainfall as the mountains shelter it from rain-producing weather systems.

Question 36

What 3 types of impacts are involved in water cycle hazards?

Answer 36

Social
Economic
Environmental

Question 37

Explain the Crop Moisture Index (CMI)

Answer 37

Measure of short-long term drought on a weekly scale used by farmers to monitor water availability during the growing season.

Question 38

How does the Pacific change during an El Nino Year?

Answer 38

Normal westerly trade winds in the Pacific weaken & may even change direction. Lack of phytoplankton in the Eastern Pacific will disrupt the food web with birds and fish reducing with a lack of food.

Question 39

How does the Pacific change during a La Nina Year?

Answer 39

Trade winds blow stronger westwards and more equatorially. Upwelling of cooler water in Western South America can create droughts from high pressure.

Question 40

What is the concept of ‘Day Zero’

Answer 40

Describes the situation where any large urban area approaches a water crisis with limited days of water supply left.

Question 41

Teleconnection

Answer 41

Refers to climate anomalies which relate to each other at large distances.

Question 42

Desertification

Answer 42

Land degradation in arid regions resulting from human activities or climatic variations.

Question 43

Flash Flooding

Answer 43

A flood with an exceptionally short lag time - often minutes or hours.

Question 44

Morbidity

Answer 44

The state of ill health

Question 45

What will climate change do to the atmosphere in the hydrological cycle

Answer 45

Water moisture in the atmosphere will increase as the carrying capacity increases with warmer temperatures, and that will also speed up evaporation from radioactive warming.

Question 46

How would deforestation impact the water cycle

Answer 46

Reduced interception & transpiration. Runoffs therefore may be far quicker which may result in flash flooding or much faster rising limbs of a storm hydrograph.

Question 47

How would climate change influence precipitation

Answer 47

More irregular and intense outbursts of precipitation.