aquifer summary

8/13/2019 Aquifer Summary

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water Depletion



A glance at the globe suggests an

inexhaustible supply of water.



The World’s Water Supply • However, only

about 3% is

fresh water.

• Of that 3%,

70% is locked

in glaciers

29% is found

underground

in aquifers

1% is found

in lakes,

rivers, &streams

Source: http://www.purdue.edu/dp/envirosoft/groundwater/src/supply2.htm



Groundwater is . . .• An important source of fresh water

(represents over 90% of the world's readilyavailable fresh water).

• Located in aquifers -- underground layers

of porous rock and soil.• Result of rain water seeping into the

ground, eventually finding its way intoaquifers.

• This underground water moves very slowlyand may take a long time to recharge orrefill.



Groundwater

Source: http://ga.water.usgs.gov/edu/earthgwaquifer.html



People around the world use the earth’s supply

of liquid fresh water for various purposes.

• Agriculture (42%)

• Electricitygeneration (39%)

• Homes/offices/hotels(11%)

• Manufacturing andmining (8%)



Global water use has changed over time. What does

this graph tell you about water withdrawal and

consumption since 1900?

Source: http://www.unep.org/vitalwater/15.htm . For more info and graphs see UNEP website.

http://www.unep.org/vitalwater/15.htm

http://www.unep.org/vitalwater/15.htm



• The demand for water is increasingdue to:

Population growthBetter technology making it easier

to access water

• But, the earth’s freshwater supply is

limited.



Water & Population

• The world’s

population is growing

at about 80 million

people a year.• Therefore, an

additional 64 billion

cubic meters of water

need to be found eachyear.



Better Technology

• People access groundwater through wells

either by hand or by diesel/electric pump.

• Diesel/electric pumps allow people to

access water much more easily than by

hand.



Aquifer Depletion

• As the demand for water increases, deeper

wells must be dug.

• Water from deeper below the earth’s surface is

more likely to be contaminated with naturally

occurring minerals, such as radium, because it

has been in contact with rock formations for

hundreds or thousands of years and mineralshave dissolved into the water.

• Since aquifers recharge slowly, wells will

eventually run dry.



Aquifer Depletion in

Waukesha, Wisconsin, USA,and Sana’a, Yemen



Sana’a, the capital of Yemen, is located in

the Middle East, one of the most water-

scarce regions of the world.



Waukesha is located near the Great Lakes,

an area with abundant water resources.



Both regions risk losing their

supply of fresh water as theiraquifers are depleted.



Waukesha & Water:

A Historical View• Late 19th century, Waukesha was a resort town

known for the healing properties of its mineral-rich water.

• Lake Michigan was polluted.

• Officials in Chicago and Milwaukee looked toWaukesha as a water source.

• In one incident in 1892, the people ofWaukesha used pistols, pitchforks, and firehoses to protect their water supply fromspeculators.

Source: Barringer, F. (2005, August 12). Growth Stirs a Battle to Draw More Water From the Great Lakes. New York Times.



Waukesha Today

• Today, Waukesha is depleting its aquifer.

• Its population increased 4.4% between

2000 and 2005.• Population of city of Waukesha = 67,658.

• Population increase has led to increased

demand for water.



Waukesha

• Deeper and deeper wells have been dug.• The current water level is more than 600

feet below its original level.

• Deeper wells = greater contamination ofwater.

• Radium content of Waukesha’s water ismore than double the acceptable level set

by the EPA in 2000.

• Radium exposure over a lifetime hasbeen linked to higher risk of cancer.



A Solution?

• One solution proposed by City of Waukesha

officials is to build a pipeline to access Lake

Michigan water.• However, a water protection plan called

“Annex 2001,” bans new diversions of water

outside the Great Lakes natural basin.

• Waukesha is 5 miles outside the Great Lakes

basin. Therefore it cannot take water.



• In spite of Annex 2001, city officials hope

their proposal will be approved by U.S.and Canadian officials.

• Supporters of this proposal state that the

amount of water Waukesha would take

would not stress the Great Lakes’ water

supply.



• Critics of Waukesha’s plan say that the

problem is not that the amount of water used

by Waukesha would damage the Great Lakes,but that a precedent will be set.

• States in the West, desperate for water, (AZ,

NV, and CA) could look to Great Lakes as

potential water source.

• Another suggested solution for Waukesha’s

water supply issues is water conservation.

• A third proposed solution is to obtain water

from west of Waukesha which would cost twice

as much.



Waukesha Questions

• Which of these solutions do you think is

best? Why?

• Can you think of some other solutions?



Sana’a, Yemen

• Sana’a, the capital of Yemen, is located at 7223

feet (2200 meters) above sea level, on a plateau

surrounded by several mountains.

• The old part of the city has been inhabited formore than 2500 years and was designated a

UNESCO World Heritage city.

• It is a generally dry place with low rainfall and

limited surface water (few rivers or streams).

• The main source of water in the region is

groundwater.



• Yemen has one of the highest population

growth rates in the world at 3.6% (in

comparison the U.S. has a population growth

rate of 0.91%).

• Sana’a, with a population of 1,747,627, isgrowing at an even higher rate as people move

from the rural areas to the city.

• The population increase raises demand for

water for drinking and growing food.

• Yemen is one of the world’s poorest countries.



Sana’a Yemen

• 60% of the people workas farmers.

• Agriculture in theSana’a basin area

accounts for 80% ofwater demand.

• Cultivation of qat (atree that has leaves that

are chewed as astimulant in Yemen)and grapes (a cashcrop) consume themajority of the water.

Urban Farming, Sana’a, Yemen, Photo credit: FAO



Better Technology

Another reason for increase in water use

is change from traditional farming and

water management methods suitable forthe region to modern farming techniques

such as powerful water pumps which

allow people to withdraw much morewater.



Sana’a and Aquifer Depletion

• Sana’a’s aquifers are dropping at a rateof about 20 feet per year.

• If this rate continues they will be depleted

by the end of decade.

• The groundwater is used in irrigated

agriculture, industry, and households.



Sana’a and Aquifer Depletion

Continued• Due to low rainfall, the groundwater does

not recharge at a rate that can keep up

with current demand and is therefore a(mostly) nonrenewable resource.

• In the Sana’a region farmers and the cityare competing for water.



Reasons for Overuse of

Groundwater

According to the United NationsEnvironment Program (UNEP) and theWorld Health Organization(WHO), the

reasons for overuse of groundwater are: – Unclear water rights and thus unregulated

extraction;

– Fuel subsidies and low import duties onagricultural equipment;

– High returns on cash crops;

– Inefficient irrigation practices.



Response to Crisis By Government

• The Yemeni government has

– prohibited the drilling of new wells without a

permit

– prohibited the establishment of newindustries that consume large amounts of

water.

• However, this has not been enough tostop depletion of the city’s aquifers.



Other Possible Solutions

• Some other suggested solutions are to

bring water from somewhere else, such as

coastal desalination plants, or to relocatethe capital.

• Some solutions suggested by

UNEP/WHO report were to reusewastewater in the city and to conserve

agricultural water.



Sana’a Questions

• Which of these solutions do you think is

best? Why?

• Can you think of some other solutions?



Questions for both Waukesha

and Sana’a • What are the similarities and differences

between Waukesha and Sana’a?

• Do you think each city needs a differentsolution? Why or why not?

• If you could create international water supply

guidelines that encouraged environmental,social, and economic sustainability what would

they be?

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