ENVR 1402 - CH.17

Why are lakes considered "temporary features on the landscape?"

- They may eventually fill with silt. - They may be emptied by the cutting of an outlet stream through the barrier that originally created them.

Earth's oceans ______.

- contain about 97 percent of all liquid water - contain about 90 percent of its biomass

Up to 70 percent of agricultural water use in developing countries is lost to ______.

- evaporation - watering parts of the land where plants do not grow - leaks in irrigation canals

The United Nations estimates approximately ______ percent of people live in a country where water supplies don't meet essential needs.

33

Depletion of groundwater ______ the water table and causes shallow wells to go dry.

lowers

Recent civil wars in Syria and Yemen are associated with declining ______ linked to climate change.

water supplies

Rank the following water compartments from the most water at the top to the compartment with the least at the bottom.

1. Oceans 2. Glaciers and polar ice 3. Groundwater 4. Atmosphere

About ______ percent of earth's water is freshwater, with salt water making up the rest.

2.4

Match each drought event with its effects on the American West.

2011-2015 Drought - Total crop yields on agricultural land were reduced by 80 percent 1930s Dust Bowl - Topsoil was stripped from millions of hectares of land, creating giant dust storms 1275 to 1299 Drought - The Aanasazi people were forced to abandon their lands as a result of this drought

By the year 2045, as many as ______ people may not have adequate access to freshwater.

4 billion

Worldwide, agriculture is responsible for _______ percent of water withdrawal.

70

What factors are responsible for the falling water levels in Lake Mead and Lake Powell?

- Changing climate - Drought - Water diversion to large cities

What are some ways to "increase" local water supplies?

- Cloud seeding - Desalination

How have farmers, tribal members, and recreational and commercial fisheries agreed to manage water on the Klamath River?

- Farmers agreed to use less water in exchange for funds to finance water conservation technology. - Farmers will let some of their land go fallow in extra dry years and instead try to grow high-value crops on a smaller part of their land.

Which of the following are freshwater compartments?

- Groundwater - Atmosphere - Glaciers and polar ice

Which of the following are true about flood or furrow irrigation?

- It can waterlog the soil, reducing crop growth. - It can lose about one-half of the irrigation water to evaporation.

Which of the following describe the aquifer depicted here?

- Its primary use is for irrigation. - It's called the Ogallala.

What are some environmental impacts resulting from dam construction?

- Large dams can induce earthquake activity. - Large amounts of water are lost to evaporation from the new reservoirs. - Plant matter builds up behind the dam, decays, and produces methane.

Industrial water use includes which of the following?

- Mining - Thermoelectric power generation - Hydroelectric power generation

Water is a renewable resource, but not all water is easy to access. Which of the following correctly describe worldwide water supplies?

- Much of it cannot be used productively. - They average out to about 400,000 gallons per person. - Much of it is located in regions with small populations.

How does sedimentation limit the life of the reservoir behind a dam?

- Sediment loads block the ports for water used in hydroelectric power generation. - Sediment loads fill in the reservoir, reducing the amount of water that can be stored.

What factors control where on the planet there will be water deficits and where there will be surpluses?

- Topography influences precipitation distribution. - Global atmospheric circulation creates regions of persistent high air pressure and low rainfall. - Proximity to water sources influences precipitation.

How can domestic water use be curbed?

- Use water-efficient appliances - Offer education on water conservation techniques. - Use low-flow shower heads.

Wastewater that has been treated can be used for ______.

- agricultural irrigation - human drinking water - water for flushing toilets

Put the following food products in order by how much water it takes to produce one pound of the product, placing the largest water user on top.

1. Chocolate 2. Beef 3. Chicken 4. Soy 5. Potatoes

Compared to the year 1980, the U.S. population is currently using ______ water per day.

10 percent less

Which of the following food products uses the most water in production?

Beef

True or false: A drought is defined as a year in which less than 2 inches of precipitation fall in a particular region.

False

True or false: The 2011-2015 drought in the American West is the worst period of drought in the history for this region.

False

Which water compartment contains the largest proportion of earth's liquid water?

Oceans

________ people often have less access to clean water than do ________.

Poor; rich people Rural; city dwellers

Globally, which type of industrial water use accounts for the greatest withdrawal?

Power production

In which compartment is water likely to have the shortest residence time?

The atmosphere

The process of groundwater infiltration is best described by which of the following statements?

The percolation of water downward into the soil

In the 1950s, the Soviet Union began diverting water from the Aral Sea for cotton and rice fields. What were the consequences of this diversion?

The sea dried up and left behind toxic chemicals that got mixed up in runoff.

Which of the following correctly describes the role of lakes in the hydrologic cycle?

They hold a minor amount of earth's water.

True or false: The U.S. Army Corps of Engineers has no new large dam and diversion projects in progress.

True

True or false: The U.S. population is using less water per capita today (2019) than it did in 1980.

True

The Ogallala Aquifer underlies eight states in the High Plains and is the primary source of water for agriculture there. Which of the following best describes the current state of the aquifer as associated with its use?

Withdrawal exceeds use, wells are going dry, and people are abandoning many places.

While house hunting, you discover a property that is located directly downhill from a former dry cleaning business. The home draws drinking water from a well. You learn that the dry cleaners went out of business last year after it was fined for illegally dumping chemical waste. Knowing what you do about aquifers, would you be concerned about groundwater contamination in the well?

Yes, groundwater contamination is a concern, since it can only take a few years for groundwater contaminants to reach the well.

Match the term to its correct definition.

Zone of Aeration - Upper soil layers where pore spaces contain both moisture and air Zone of Saturation - Lower soil layers where pore spaces are completely filled with water

The part of the soil layer where pore spaces are filled with both air and water is known as the zone of ______________. The part of the soil layer where pore spaces are completely filled with water is known as the zone of ______________.

aeration; saturation

Discharge is a measure of the ______.

amount of water that passes through a fixed point on a river per unit time

A(n) _____________ is a geological layer that readily holds and transmits groundwater, and is usually underlain by a relatively impermeable layer that prevents water from seeping out at the bottom.

aquifer

A(n) ______ occurs where water rises to the surface from underground pressure without the need for a pump.

artesian spring

In 2019, about 2 ______ people live in countries with insufficient freshwater resources.

billion

There are many deadly threats to salmon from ___________ including being chewed up in a hydroelectric turbine, increased disease risk due to warm waters in the reservoir, and a disturbance of their natural migration cycle.

dams

Global human water use is ______.

increasing

The leeward side of mountains experience ______ rainfall compared to the windward side of mountains, resulting in a rain shadow.

less

The areas located between 20° and 40° degrees latitude, in both hemispheres, have ______.

low amounts of precipitation

The largest single industrial producer of degraded water is ______ because as much as 80 percent of the water used during production is not treated.

mining and energy production

One of the benefits of drip irrigation is that ______.

nearly all the water is used by plants

Two-thirds of China's population lives in the ______ whereas two-thirds of the precipitation falls in the ______; major water transfer projects are underway to provide water to millions of people.

north; south

Water infiltrates the ground surface from the ______________ zone, replenishing the aquifer beneath.

recharge

Groundwater is replenished in aquifers at the ______.

recharge zone

The main function of the hydrologic cycle is to ________.

redistribute water around the globe

A major role of the atmosphere, as it pertains to being a water supply storage compartment, is to _______.

redistribute water over landmasses

In light of modern water usage issues and related environmental problems, many of the 75,000 dams in the United States will be ______ in the coming years.

removed to restore aquatic habitats

Excessive pumping of groundwater in ______ has resulted in 10 m of subsidence over the past 50 years.

the San Joaquin Valley, California,

The shrinking of glaciers worldwide is a major concern because ______.

they provide freshwater to a large amount of people

Dams are built for all the following purposes except ______.

to recreate natural ecosystems

The fastest-growing segment of California's water supply, growing at about 30 percent per year, comes from ______.

treated sewage effluent

When the demand for water in an area is greater than the available water supply, or if poor water quality limits its use, the area is experiencing ______.

water scarcity

The top of the zone of saturation, which often follows the contours of surface topography, is the ______.

water table

Skirmishes over water are exacerbated by _____.

- the fact that some aquifers underlie multiple nations - major rivers that pass through many countries - the fact that many great reservoirs of water cross international borders - increasing water scarcity, as a result of climate change

China's water shortage issues ______.

- threaten hundreds of major cities, including Beijing - have led to a massive water distribution effort to move water from the Yangtze River northward

Human development, such as urbanization or road building, tends to ______ water infiltration in recharge zones.

decrease

The Sanmenxia Dam, built in 1957 for power generation, was rendered useless by the 1990s because ______.

sediment rapidly accumulated behind the dam, significantly reducing energy production

The water _______________ represents the top of the saturated zone and often reflects the contours of the land surface above it.

table

States within the Colorado River watershed are withdrawing more water than is sustainable, leading to declining water levels in Lake Mead and Lake Powell because ______.

the river's annual flow was overestimated when states' water rights were allocated

Subsidence is caused by ______.

withdrawing large amounts of groundwater

What worldwide sector accounts for the majority of water withdrawal?

Agriculture

The diversion of water from the ______ in the former Soviet Union is a classic example of just how bad a diversion can be for both people and ecosystems.

Aral Sea

Which of the following are water conservation techniques?

- Do not flush the toilet every time. - Use a low-volume showerhead. - Use drought-resistant plants in your landscaping.

Dams are built because they ________.

- are used to store runoff for nonrainy seasons - help control flooding - are used for energy generation

Climate change is expected to ________.

- cause the southwestern U.S. to become even drier - increase water scarcity and water stress in many areas

Agricultural water loss can be reduced by using ______.

- intercropping techniques - low-volume (drip) irrigation - cover crops

Rank the following uses of water inside an average North American home from the most water used at the top to the least water used at the bottom.

1. Toilet Flushing 2. Showering 3. Laundry

List the parts of an aquifer in the correct order, starting from the top (at the earth's surface) and descending downward (deeper).

1. Zone of aeration 2. Water table 3. Zone of saturation

__________________ irrigation carefully releases water to the plant roots, minimizing water loss.

Drip

irrigation carefully releases water to the plant roots, minimizing water loss.

Drip

Which of the following types of irrigation is considered to be the most efficient?

Drip irrigation

What is the name for a period of consistently below-average precipitation that has adverse effects on both humans and natural environments?

Drought

Which sentence best describes what we predict to happen to precipitation patterns from current climate change?

Dry areas become drier, wet areas become wetter.

Match the region of the United States with the structure of water policy used there.

Eastern United States - Water policy based on riparian use rights Western United States - Water policy based on prior appropriation rights

Where is water stress most likely to occur?

In poor countries where per capita water supply is low

Match the phrases to describe some of the negative consequences of building dams.

Water in reservoirs - is lost through evaporation and seepage Decaying plant material in reservoirs - produces and releases methane Dam building - has dislocated millions of people

Which of these best describes the word artesian?

Water moving out of the ground without a pump

What does Fortune magazine mean when they state, "Water will be to the 21st century what oil was to the 20th?"

Water will be a resource that will be fought over.

Match the following term to its definition.

Water withdrawal - The total amount of river taken from a lake, river, or aquifer for any purpose Water consumption - The fraction of removed water that is lost in transmission, evaporation, absorption, chemical transformation, and so on

The United States and Australia have been able to encourage water conservation by ______.

charging higher amounts to users of public water sources

The Amazon River has a ____________________ of 175,000 cubic meters per second, putting it at the top of the list for the river carrying the most water in a given amount of time.

discharge

Charging a higher proportion of real costs to users of public water projects tends to ______.

encourage water conservation

The process of ______ requires as much as 23 million liters of water for a single well, and as much as 40 percent of that water returns to the surface contaminated with toxic materials.

fracking

About 2.4 percent of the water on earth is _______________ water, and most of it is locked up in glaciers, ice caps, and snowfields.

fresh

When water evaporates from moist surfaces, falls again as rain or snow, passes through living organisms, and returns to the ocean, the process is known as the _____________________ cycle.

hydrologic

Currently, industrialized countries' water use is ________, and worldwide water use is ________.

stabilizing; increasing

Geographic areas located along ______ receive the most precipitation (overall).

the equator

The eastern and westerns regions of the United States have, in general, different water use policies because ______.

there is a surplus of water in the east and a scarcity of water in the west

Groundwater accounts for about ______ percent of the drinking water and domestic use of water by the U.S. rural population.

95

Water scarcity occurs when ______.

the demand for water exceeds the available supply

What characteristics of wetlands are important for humans?

- Their plant growth stabilizes the soil. - They hold back surface runoff, allowing time for infiltration into aquifers. - They help slow waters down, decreasing the severity of flooding and erosion.

How are dams lethal to salmon?

- They die going through the hydroelectric turbines. - Adult fish are blocked from migrating to upstream spawning areas. - Slow-moving river waters from the dam slow migration to the ocean, throwing off their time-sensitive biological changes.

How do mountains affect water distribution?

- They serve in the creation of clouds. - They serve in encouraging rainfall as air rises and cools causing moisture to condense. - They create rain shadows where the leeward side of the mountain receives less precipitation.

Water withdrawal is the ______.

- removal of water from an aquifer - removal of water from a lake

Several different methods of desalination are currently used to produce drinking water from salt water, including ______.

- reverse osmosis - thermal distillation

When Lake Mead reaches "dead pool" levels, then ______.

- water withdrawals will no longer be possible - the dam will no longer be able to generate power

Glacier meltwaters from the ______ provide freshwater for 25% of the world's population.

Himalayas

What is the name of the process in the hydrologic cycle in which water moves from the ground surface downward into groundwater?

Infiltration

True or false: Water is a renewable resource.

True

What human activity decreases the amount of water that would otherwise naturally recharge into an aquifer?

Urbanization

Match the area with the average domestic water use per person per day.

Wealthy countries - 500 to 800 liters Developing countries - 30 to 150 liters

The declining water supplies that have occurred and will be made worse through climate change will most assuredly lead to even more and larger ______, at least in the short term.

conflicts and wars

Some of the negative consequences of large ______________ building projects include the displacement of millions of people, the buildup of vegetation in the reservoir that releases methane into the atmosphere, and the loss of water through seepage and evaporation in the reservoir.

dam

When Lake Mead reaches a water level of about 1,050 feet, it will no longer be able to drain by gravity; we refer to this situation as it's ______________ pool level.

dead

The process of ________________, which removes salt from the ocean or brackish waters, is already being used in the Middle East and parts of the United States and has the potential to provide us with all of the freshwater we could use.

desalination

Thermal distillation and reverse osmosis are the two main processes used in ______, where fresh drinking water is produced from salt water.

desalination

When salts are removed from ocean water or brackish lakes and made available as fresh water for drinking, this process is called ________.

desalination

A "walking" wetland describes the process where ______.

farmers agree to flood fields on a rotating basis to provide habitat to waterfowl

Saltwater intrusion, due to groundwater depletion, results in ______.

freshwater being contaminated with seawater

Nearly 40 percent of freshwater used for agricultural and domestic use in the United States comes from ______.

groundwater

In the typical aquifer, it can take anywhere from a few ______ to a few ______ for water movement to carry contaminants a few hundred meters.

hours; years

Clearing forests results in lower rainfall, since plants are no longer there to transpire water. This is an example of ________ affecting water distribution.

human activities

The length of time water typically stays in a compartment (i.e., the oceans, rivers, lakes, etc.) is its ________ time.

residence

Desalination and cloud ________________ are two ways to increase local water supplies.

seeding

The destruction of vast amounts of wetlands has resulted in more ______.

severe flooding and erosion

The atmosphere is among the ________ of the major water compartments on earth in terms of total water supply.

smallest

If a region does not have adequate renewable water supplies to meet essential human and ecosystem needs, the region is experiencing water _____________________

stress