EASC 201 Exam 2 part 4

What is the largest global water user?

Agriculture.

What are the primary uses of water in the United States?

Thermoelectric power, irrigation, public supply, industrial use, livestock, aquaculture, mining, and domestic use.

Why does water use differ globally compared to the United States?

Differences in economies, climates, technologies, infrastructure, and land uses create different patterns of water demand.

Why is agriculture a major global water user?

Crop irrigation and livestock production require large amounts of water.

Why is thermoelectric power a major water user in the United States?

Many U.S. power plants withdraw large amounts of water for cooling.

What is surface water?

Water found on Earth's surface, such as rivers, lakes, streams, and reservoirs.

What is groundwater?

Water stored underground in soil and rock formations called aquifers.

What is the primary difference between surface water and groundwater?

Surface water is above ground and moves quickly through the water cycle, while groundwater is stored underground and moves much more slowly.

What is residence time in the hydrologic cycle?

The average amount of time water stays in a particular part of the hydrologic cycle.

Why is groundwater often slower to recharge than surface water?

Water must infiltrate through soil and rock, which is a slow process.

What are the risks associated with the overuse of groundwater?

Water shortages, land subsidence, and ecosystem impacts.

What is the difference between water withdrawal and water consumption?

Withdrawal is the total amount of water removed from a source; consumption is the portion of withdrawn water that is not returned to the source.

Why have some U.S. water withdrawals declined over time?

Improved efficiency, better cooling technologies, conservation, policy changes, and shifts in industry and energy systems.

What is a water footprint?

The total amount of freshwater used directly and indirectly to produce goods, services, or support a person, activity, or organization.

What is the difference between a direct and indirect water footprint?

A direct footprint is water used by a person or activity; an indirect footprint is water used behind the scenes to produce goods or services.

What is freshwater scarcity?

A condition in which available freshwater resources are insufficient to meet human and environmental demands.

What is the difference between physical and economic water scarcity?

Physical scarcity occurs when there is not enough natural freshwater; economic scarcity occurs when water exists but people lack access due to poor infrastructure or poverty.

Why is freshwater scarcity uneven across the world?

It depends on climate, population, development, water management, infrastructure, and demand.

Why is the western United States often more water-stressed?

Lower rainfall, higher evaporation, irrigation demand, population growth, and long-term drought.

Can freshwater scarcity occur in wetter regions?

Yes, if demand exceeds supply, pollution reduces usable water, infrastructure is limited, or seasonal shortages occur.

How does climate change affect freshwater scarcity?

It can alter precipitation, increase drought, increase evaporation, reduce snowpack, and intensify water stress.

What are examples of surface water use?

Reservoirs, rivers, and lakes used for drinking water, irrigation, recreation, and electricity generation.

What are examples of groundwater use?

Wells for drinking water, irrigation, and industrial or municipal supply.

Why is surface water considered vulnerable?

It is exposed to drought, pollution, evaporation, and changing river flow.