Water Resources Lecture

A set of question-and-answer flashcards covering hidden water costs, Earth’s water distribution, ocean roles, water sources, the water cycle, and human water use.

Which sector is the largest global consumer of water?

Agriculture (farming and irrigation)

Roughly what percentage of all the water on Earth is usable by humans?

About 1 percent

Of the usable freshwater, what percentage is stored as groundwater?

99 percent

What fraction of Earth’s total water is found in the oceans?

97 percent

Name the five major ocean basins of Earth.

Pacific, Atlantic, Indian, Arctic, and Southern Oceans

Which ocean is the largest body of water on the planet?

The Pacific Ocean

What two key roles does the ocean play in regulating Earth’s climate?

It helps keep global temperature steady and redistributes heat around the planet.

Define evaporation in the water cycle.

The process in which liquid water is converted into water vapor (gas).

What water-cycle process involves water vapor cooling and forming tiny droplets?

Condensation

During which process does water return to Earth’s surface as rain or snow?

Precipitation

What term describes water flowing over land into streams and rivers after precipitation?

Surface runoff

What is transpiration?

Evaporation from the plants.

What is percolation?

The downward movement of water through soil and rock to recharge groundwater.

According to the Solar Nebula Theory, how was additional water delivered to early Earth?

By water-bearing meteors containing water isotopes.

In which direction do streams always flow relative to elevation?

From higher to lower elevations (downhill).

What is the largest type of stream that carries significant water from high to low regions?

A river

The place where a stream begins is called its .

Source

Where a river empties into another body of water is known as its .

Mouth

What is a tributary?

A smaller stream that flows into a larger stream or river.

Sediment deposited at a river’s mouth can form what landform?

A delta

The land area that may flood when a river overflows is called the .

Floodplain

How do ponds differ from lakes?

Ponds are smaller, without any outlet, and are water sources are rainwater and underground springs.

List three ecological benefits provided by wetlands.

They conserve water resources, support diverse ecosystems, and help prevent floods (also increase river flows).

Why is groundwater often used for drinking water?

It is usually of high quality due to natural soil and rock filtration.

When is groundwater considered renewable?

As long as it is not withdrawn faster than it is naturally recharged.

How are wells created?

By drilling or digging through rock layers to reach groundwater.

Why are oceans crucial to the global water cycle?

They are the main source of evaporation and receive most precipitation.

Approximately what percentage of indoor household water use goes to toilets?

20 percent

Which two other indoor uses each account for roughly 19 percent of household water?

Clothes washers and showers (faucets are also about 19 percent).

Name four main categories of human water use.

Agricultural, industrial, household (domestic), and recreational uses

For roughly how long has the total amount of water on Earth remained about the same?

At least the last 220 million years

What is meant by a planet’s “habitable zone” when discussing water?

The orbital region around a star where temperatures allow liquid water to exist (not too hot or too cold).

About what percentage of Earth’s freshwater is locked in ice caps and glaciers?

Roughly 77 percent of freshwater

Give three examples of streams besides rivers.

Creeks, brooks, and tributaries