Water supply, use, and management lecture ppt_ch21

Water Water Supply, Supply,

UseUse and and

ManagementManagement

Tanya j.Tanya j.

A Brief Global A Brief Global PerspectivePerspective

We are facing a growing global water We are facing a growing global water shortage linked to the food supply.shortage linked to the food supply.

Global hydrologic cycleGlobal hydrologic cycle Transfers water from the atmosphere, to land, Transfers water from the atmosphere, to land,

to oceans and back to atmosphereto oceans and back to atmosphere 97% in oceans97% in oceans 2% in ice2% in ice Only 0.001% in atmosphereOnly 0.001% in atmosphere

A Brief Global A Brief Global PerspectivePerspective

At Earth’s surface water can be found in At Earth’s surface water can be found in liquid, solid or gaseous form.liquid, solid or gaseous form. Residence time varies from a few days to Residence time varies from a few days to

thousands of yearsthousands of years

Amount of water for which all people, Amount of water for which all people, animals and plants compete is less than animals and plants compete is less than 1%1% Industrial production increases water useIndustrial production increases water use Mass of water used 1000x total production Mass of water used 1000x total production

of mineralsof minerals

Water Supply: A US Water Supply: A US ExampleExample

Amount of water vapor passing over the US Amount of water vapor passing over the US every day ~ 152,000 million mevery day ~ 152,000 million m33

10% falls as precipitation (66% of which is 10% falls as precipitation (66% of which is evaporated or transpired)evaporated or transpired)

Only 34% enters surface or groundwaterOnly 34% enters surface or groundwater

DroughtsDroughts

Because there are large annual and regional Because there are large annual and regional variations in stream flow, even areas with variations in stream flow, even areas with high precipitation and runoff may suffer high precipitation and runoff may suffer from droughts.from droughts.

Some changes every Some changes every body can seebody can see

Salt content of the water has increasedSalt content of the water has increased

Dust storms from dry salt flatsDust storms from dry salt flats

Climate changesClimate changes Winters colder, summers warmerWinters colder, summers warmer Loss of fishing and decline of tourismLoss of fishing and decline of tourism

Transport of WaterTransport of Water

Ancient civilizations constructed canals Ancient civilizations constructed canals and aqueducts to transport water and aqueducts to transport water From distant river to where it is neededFrom distant river to where it is needed

In modern civilization water moved from In modern civilization water moved from areas of abundant rain and snow fall to areas of abundant rain and snow fall to areas of high usageareas of high usage E.g. California moves water from north to E.g. California moves water from north to

southsouth E.g. New York City has had to obtain water E.g. New York City has had to obtain water

from farther and farther awayfrom farther and farther away

Some Trends in Water Some Trends in Water UseUse

Trends in freshwater withdrawals by water-Trends in freshwater withdrawals by water-use categories suggests that:use categories suggests that: 1. The major uses of water are for irrigation 1. The major uses of water are for irrigation

and the thermoelectric industry.and the thermoelectric industry. 2. Water use for irrigation increased from 2. Water use for irrigation increased from

1950-1980. It decreased and leveled off from 1950-1980. It decreased and leveled off from 1985-2000 1985-2000 due to better irrigation efficiency, crop type and due to better irrigation efficiency, crop type and

higher energy costs.higher energy costs.

Some Trends in Water Some Trends in Water UseUse

3. Water use by thermoelectric industry 3. Water use by thermoelectric industry decreased slightly in 1980, and stabilized in decreased slightly in 1980, and stabilized in 1985.1985. Due to reticulating water for coolingDue to reticulating water for cooling

4. Water for public and rural supplies 4. Water for public and rural supplies continued to increase through the period from continued to increase through the period from 1950 to 20001950 to 2000 presumably related to the increase in human presumably related to the increase in human

population.population.

Water ConservationWater Conservation

The careful use and protection of water The careful use and protection of water resourcesresources Involves the quantity of water used and the Involves the quantity of water used and the

qualityquality Important component of sustainable water Important component of sustainable water

useuse Expected that a number innovations will Expected that a number innovations will

reduce the total withdrawalsreduce the total withdrawals

Agricultural UseAgricultural Use

Improved irrigation could reduce Improved irrigation could reduce agricultural withdrawals by 20 to 30%agricultural withdrawals by 20 to 30% Tremendous savings because ag is the biggest Tremendous savings because ag is the biggest

useruser


Suggestions for conservation:Suggestions for conservation: Price agricultural water to encourage Price agricultural water to encourage

conservation conservation Use lined or covered canals that reduce Use lined or covered canals that reduce

seepage and evaporation.seepage and evaporation. Use computer monitoring and schedule Use computer monitoring and schedule

release of water for maximum efficiency.release of water for maximum efficiency. Integrate the use of surface water and Integrate the use of surface water and

groundwater to more effectively use the groundwater to more effectively use the total resource.total resource.


Irrigate at times when evaporation is minimal, Irrigate at times when evaporation is minimal, such as at night or in the early morning.such as at night or in the early morning.

Use improved irrigation systems, such as Use improved irrigation systems, such as sprinklers or drip irrigation, that more sprinklers or drip irrigation, that more effectively apply water to crops.effectively apply water to crops.

Improve the soil to increase infiltration and Improve the soil to increase infiltration and minimize runoff.minimize runoff.

Encourage the development of crops that Encourage the development of crops that require less water or are more salt tolerant.require less water or are more salt tolerant.

Domestic UseDomestic Use

Accounts for about 10% of total national Accounts for about 10% of total national water withdrawalswater withdrawals But concentrated in urban areasBut concentrated in urban areas May pose major local problemsMay pose major local problems


Water use can be substantially reduced Water use can be substantially reduced by:by: In semi-arid regions, replace lawns with In semi-arid regions, replace lawns with

decorative gravels and native plants.decorative gravels and native plants. Use more efficient bathroom fixtures.Use more efficient bathroom fixtures. Turn off water when not absolutely needed.Turn off water when not absolutely needed. Flush the toilet only when really necessary.Flush the toilet only when really necessary. Fix all leaks quickly. Fix all leaks quickly.


Purchase dishwashers and washing machines Purchase dishwashers and washing machines that minimize water consumption.that minimize water consumption.

Take a long bath rather than a long shower.Take a long bath rather than a long shower. Sweep sidewalks and driveways.Sweep sidewalks and driveways. Using gray water to water vegetation. Using gray water to water vegetation. Water lawns and plants at cool times to Water lawns and plants at cool times to

reduce evaporation.reduce evaporation.


Use drip irrigation and place water-holding Use drip irrigation and place water-holding mulch around garden plants.mulch around garden plants.

Plant drought-resistant vegetation.Plant drought-resistant vegetation. Learn how to read the water meter to monitor Learn how to read the water meter to monitor

for unobserved leaks and record your for unobserved leaks and record your conservation successes.conservation successes.

Use reclaimed waterUse reclaimed water

Industry and Industry and Manufacturing UseManufacturing Use

Water conservation measures that can be Water conservation measures that can be taken by industry:taken by industry: Using cooling towers that use little or no Using cooling towers that use little or no

waterwater In-plant water treatment and recyclingIn-plant water treatment and recycling

Perception and Water Perception and Water UseUse

Perception of water is based partly on its Perception of water is based partly on its price and availability.price and availability. If water is abundant and inexpensive, we If water is abundant and inexpensive, we

don’t think much about it. don’t think much about it. If water is scarce or expensive, it is If water is scarce or expensive, it is

another matter.another matter. E.g. people in Tucson pay about 100% more E.g. people in Tucson pay about 100% more

for water than people in Phoenix.for water than people in Phoenix. Tucson residence use less water per person Tucson residence use less water per person

per dayper day

Sustainability and Water Sustainability and Water ManagementManagement

From a water supply use and management From a water supply use and management perspective, sustainable water use defined perspective, sustainable water use defined as:as: use of water resources by people in a way use of water resources by people in a way

that allows society to develop and flourish that allows society to develop and flourish into an indefinite futureinto an indefinite future

W/o degrading the various components of the W/o degrading the various components of the hydrologic cycle or the ecological systems hydrologic cycle or the ecological systems that depend on it.that depend on it.

Sustainable Water UseSustainable Water Use

General criteria:General criteria: Develop water resources in sufficient volume Develop water resources in sufficient volume

to maintain human health and well-being.to maintain human health and well-being. Provide sufficient water resources to Provide sufficient water resources to

guarantee the health and maintenance of guarantee the health and maintenance of ecosystems.ecosystems.

Ensure minimum standards of water quality Ensure minimum standards of water quality for the various users of water resources.for the various users of water resources.

Sustainable Water UseSustainable Water Use

Ensure that actions of humans do not damage Ensure that actions of humans do not damage or reduce long-term renewability of water or reduce long-term renewability of water resources.resources.

Promote the use of water-efficient technology Promote the use of water-efficient technology and practice.and practice.

Gradually eliminate water pricing policies that Gradually eliminate water pricing policies that subsidize the inefficient use of water.subsidize the inefficient use of water.

Water ManagementWater Management

Options for minimizing potential problems:Options for minimizing potential problems: Alternating water supplies and managing Alternating water supplies and managing

existing supplies betterexisting supplies better Towing icebergsTowing icebergs As price goes up many innovative programs As price goes up many innovative programs

are possible.are possible.

A Master Plan for Water A Master Plan for Water ManagementManagement

New management philosophy is that surface New management philosophy is that surface water and groundwater are both subject to water and groundwater are both subject to natural flux with time. natural flux with time. In wet years, there is plenty of surface water, In wet years, there is plenty of surface water,

and the near-surface groundwater resources and the near-surface groundwater resources are replenished.are replenished.

During dry years, specific plans to supply During dry years, specific plans to supply water on an emergency basis must be in place water on an emergency basis must be in place and ready to use.and ready to use.

A Master Plan for Water A Master Plan for Water ManagementManagement

Advanced planning may includeAdvanced planning may include Drilling to wells that are presently isolatedDrilling to wells that are presently isolated Reuse of waste waterReuse of waste water Develop surface water and use groundwater Develop surface water and use groundwater

in dry yearsin dry years In wet years pump excess surface water In wet years pump excess surface water

underground to recharge groundwaterunderground to recharge groundwater

Water Management and Water Management and the Environmentthe Environment

Often a good deal of controversy surrounds Often a good deal of controversy surrounds water developmentwater development Dams, canals, wetlands modificationDams, canals, wetlands modification Resolution of development involves input Resolution of development involves input

from a variety of government and public from a variety of government and public groupsgroups

Channelization and the Channelization and the EnvironmentEnvironment

Channelization of streams consists of Channelization of streams consists of straightening, deepening, widening, straightening, deepening, widening, clearing, or lining existing stream channels.clearing, or lining existing stream channels. Engineering technique that has been used to Engineering technique that has been used to

control floods, improve drainage, control control floods, improve drainage, control erosion, and improve navigationerosion, and improve navigation

Channelization and the Channelization and the EnvironmentEnvironment

Adverse environmental effects, including Adverse environmental effects, including the following:the following: Degradation of the stream’s hydrologic qualities;Degradation of the stream’s hydrologic qualities;

nearly all riffle flow, resulting in loss of important fish nearly all riffle flow, resulting in loss of important fish habitats.habitats.

Removal of vegetation along the watercourse, Removal of vegetation along the watercourse, which removes wildlife habitats and shading of which removes wildlife habitats and shading of the water.the water.

Downstream flooding where the channelized flow Downstream flooding where the channelized flow ends.ends.

Damage or loss of wetlands.Damage or loss of wetlands. Aesthetic degradation.Aesthetic degradation.

The Colorado RiverThe Colorado River

For its size has a modest flow but is one of For its size has a modest flow but is one of the most regulated and controversial bodies the most regulated and controversial bodies of water in the world.of water in the world. Total flow was apportioned among various Total flow was apportioned among various

users in 1922users in 1922 No water allowed for environmental purposesNo water allowed for environmental purposes Water rarely flows into the Gulf, all stored and Water rarely flows into the Gulf, all stored and

used upstream. used upstream. Damaged deltaDamaged delta


Two largest reservoirs- Hoover Dam and Two largest reservoirs- Hoover Dam and Glen Canyon DamGlen Canyon Dam Stored about 80% of total in the basinStored about 80% of total in the basin Represents a buffer of several years water Represents a buffer of several years water

supply.supply. Changing hydrology of the river changed Changing hydrology of the river changed

other aspectsother aspects Rapids, sediment load, and vegetationRapids, sediment load, and vegetation


Record snowmelt in the Rocky Mountains in Record snowmelt in the Rocky Mountains in 1983 forced the release of water from Glen 1983 forced the release of water from Glen Canyon DamCanyon Dam Three times normal but similar to spring Three times normal but similar to spring

floods before the dam was built.floods before the dam was built. Beneficial to the river, highlighted the Beneficial to the river, highlighted the

importance of floods in maintaining a natural importance of floods in maintaining a natural state.state.


As an experiment “flood” waters released in As an experiment “flood” waters released in 19961996 Two weeks at full floodTwo weeks at full flood As a result 55 new sandbars formed and 75% As a result 55 new sandbars formed and 75%

of existing sandbars increased in size, of existing sandbars increased in size, rejuvenated marshes and backwaters.rejuvenated marshes and backwaters.

Hailed a success; hoped that what was Hailed a success; hoped that what was learned can help restore other river impacted learned can help restore other river impacted by dams.by dams.

Global Water Shortage Global Water Shortage Linked to Food SupplyLinked to Food Supply

Both surface water and groundwater Both surface water and groundwater are being stressed and depleted:are being stressed and depleted: Groundwater in the United States, China, Groundwater in the United States, China,

India, Pakistan, Mexico, and many other India, Pakistan, Mexico, and many other countries is being minedcountries is being mined used faster than it is being renewedused faster than it is being renewed

Large bodies of water—for example, the Large bodies of water—for example, the Aral Sea—are drying up.Aral Sea—are drying up.

Large rivers, including the Colorado in the Large rivers, including the Colorado in the US and the Yellow in China, do not deliver US and the Yellow in China, do not deliver any water to the ocean in some seasons any water to the ocean in some seasons or years. or years.


As human population grows there is As human population grows there is growing concern that there won’t be growing concern that there won’t be sufficient water to grow the food to feed 8-9 sufficient water to grow the food to feed 8-9 billion people.billion people. Food shortage linked to water resources a Food shortage linked to water resources a

real possibility. real possibility. Water also linked to energy (fuel to pump) as Water also linked to energy (fuel to pump) as

energy cost goes up so does cost of food.energy cost goes up so does cost of food.


SolutionSolution Control human population growthControl human population growth Conserve and sustain water resourcesConserve and sustain water resources Need to be proactive now before significant Need to be proactive now before significant

food shortages develop.food shortages develop.

Water supply, use, and management lecture ppt_ch21

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