U7L2 Availability of Water

Question 1

What percentage of earth is covered in water?

Answer 1

71%

Question 2

Out of all the water that is on earth, how much of it is fresh water?

Answer 2

2.5%

Question 3

Out of all the fresh water on earth, how much of it is surface water?

Answer 3

1.2%

Question 4

What is the definition is aquitard?

Answer 4

A layer of rock that allows a small mount of liquid to pass through

Question 5

What is the definition of artesian well?

Answer 5

A well under sufficient pressure such that water flows upward to the surface.

Question 6

What is the definition of water table?

Answer 6

The boundary between unsaturated ground and saturated ground

Question 7

What percentage of fresh water is stored underground?

Answer 7

30%

Question 8

What affects the availability of ground water?

Answer 8

It depends on the surface and the climate

Question 9

What determines the amount of water an aquifer will hold?

Answer 9

The permeability of rocks

Question 10

How does the permeability of rock determine how much ground water there is?

Answer 10

As rainfall reaches the ground, permeable rocks allow the water to flow through them and form aquifers. Permeable rocks on the ground can lead to more ground water and less surface water. Impermeable rocks can lead to less ground water and more surface water.

Question 11

What is the definition of permeability of rocks?

Answer 11

The ease with which rocks allow liquids to pass through

Question 12

What is the definition of aquifer?

Answer 12

An area of rock that absorbs and holds water that exists below the water table.

Question 13

Which climate regions are most likely to suffer from drought?

Answer 13

Arid regions with low precipitation levels

Question 14

What happens when a drought occurs?

Answer 14

When drought occurs, the flow of streams and rivers declines, and water levels in lakes, wells, and reservoirs fall.

Question 15

What is the definition of drought?

Answer 15

A period of drier-than-normal conditions resulting from a decrease in precipitation levels over weeks, months, or years

Question 16

Where are polar climates found?

Answer 16

Near the north and south poles

Question 17

How are polar climates characterized?

Answer 17

By frigid temperatures, and because of the cold air it can hold very little moisture, resulting in snowfall.

Question 18

True or false.

Antarctica is technically a desert, due to its very low level of precipitation.

Answer 18

True

Question 19

Where are temperate climates found?

Answer 19

Found around the halfway points between the poles and the equator

Question 20

What is it like in temperate climates?

Answer 20

The zones have highly variable temperatures through their seasons, with precipitation falling year-round

Question 21

Where are the tropical climates found?

Answer 21

Near the equator and are characterized by warm temperatures year-round.

Question 22

What major seasons do tropical climates have?

Answer 22

Rainy seasons and dry seasons

Question 23

How does the tropical rain belt in tropical climates makes up the seasons?

Answer 23

These seasons are influenced by the tropical rain belt, which moves from the Northern Hemisphere to the Southern Hemisphere, then back north over the course of the year, due to the tilt of Earth’s axis. As the areas with the most direct sunlight heat up, there is more evaporation, which in turn causes more precipitation.

Question 24

What is is like in Mediterranean climates?

Answer 24

Rainy winter seasons and dry summer seasons

Question 25

Where are Mediterranean climates found?

Answer 25

These climates are found in the mid-latitudes on the western coasts of the continents. In these regions, oceanic currents help to keep the summers dry and the winters mild and rainy.

Question 26

What is it like in arid or desert climates?

Answer 26

Arid or desert climates have a greater rate of evaporation than precipitation.

Question 27

Where are most deserts found?

Answer 27

While there are cold deserts, such as found in Antarctica, hot deserts make up the vast majority of arid regions. In fact, hot deserts are the most abundant climate on Earth.

Question 28

What are prevailing winds?

Answer 28

Prevailing winds are the winds that come primarily from one direction over a specific area on Earth. They are caused by the uneven heating of Earth’s surface and by Earth’s rotation.

Question 29

What do prevailing winds do?

Answer 29

These winds carry masses of air from region to region. If a mass of air contains a great deal of moisture, precipitation occurs. During winter, the West Coast of North America gets a lot of rain because of prevailing winds. In Asia, these winds cause some regions to have monsoons while others are deserts.

Question 30

How does temperature affect water availability?

Answer 30

The higher temperature causes large amounts of water to be evaporated from the Earth’s surface through evaporation and transpiration. Water evaporation from ocean, lake, sea and land surfaces due to higher temperatures leads to decrease in water availability in some regions. Higher temperatures also lead to increase amount of moisture in the air, leading to increase in precipitation levels in some regions.

Question 31

How does precipitation occur near the ocean and mountains?

Answer 31

Wind blows warm moist air from the ocean. The warm air is forced to climb up the mountain, the windward side, also known as the upwind side, has a cool and wet climate. As the air rises, it cools and condenses due to the lower temperature. Clouds form and precipitation occurs before the air passes over the top of the mountain. The air then travels down the downwind side of the mountain, the air warms, compresses, and evaporates. This side has worm and dry climate.

Question 32

What causes the decline water resources?

Answer 32

Worldwide increases in human population affects Earth’s water supply. As the population increases, worldwide demand for water increases.

Question 33

How is the demand for water related to worldwide population growth?

Answer 33

As the population increases worldwide, the demand for water increases.

Question 34

As humans consume more water than can be recharged, changes to Earth’s surface and water supply occur. Some major impacts are as follows:

Answer 34

- lowering of the water table - land subsidence - saltwater intrusion

Question 35

How does land subsidence occur?

Answer 35

If the water table is not refilled at the rate that water is taken out

Question 36

What is the definition of land subsidence?

Answer 36

Sinking of land

Question 37

What is the definition of saltwater intrusion?

Answer 37

The moment of saline water into freshwater aquifers

Question 38

What is saltwater intrusion caused?

Answer 38

Saltwater intrusion is caused when fresh water is contaminated by an influx of salt water from an adjacent ocean.

Question 39

True or false. Saltwater intrusion can be a naturally occurring process.

Answer 39

True

Question 40

What is the major cause of saltwater intrusion?

Answer 40

A major cause of this contamination is over-pumping from our aquifers. As water is pumped from aquifers, the water table drops. At rapid rates, this forms a cone of depression because fresh water is not being replenished as fast as it is being pumped. Salt water rises and can move into the space where fresh water is depleted. If fresh water is not replenished fast enough, salt water from nearby oceans can seep inland and upward into the area.

Question 41

What is brackish water?

Answer 41

Brackish water contains more salt than fresh water, but not as much as salt water. This affects wells close to the coast, making them vulnerable to contamination.

Question 42

How do impacts of population growth on Earth's water supply affect future populations?

Answer 42

Impacts such as saltwater intrusion could cause less clean drinking water to be available for future generations. As the water table lowers and is not recharged as quickly, the supply of water could be much less for future populations. As land continues to sink, threats of increased saltwater intrusion are more likely.

Question 43

Hypothesize what could happen to Earth's water supply if the population were to decrease.

Answer 43

If the population started to decrease, the water supply could start to recharge at a faster rate. Water could be replenished in the aquifer, making water more accessible to future generations. Less threat of land subsidence and saltwater intrusion could be an overall outcome.