Water Quality and Quantity

8/9/2019 Water Quality and Quantity

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Water Resources and Pollution


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Importance of water

About 71% of the earths surface

is water

All organisms are made of mostly

water

Water plays a ey role insculpting the earths surface!

moderating climate! and diluting

pollutants


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"ome important properties of water

#$ists as a liuid o&er a wide range of temperatures

'hanges temperature &ery slowly

It taes a lot of heat to e&aporate water

'an dissol&e a &ariety of compounds

(igh surface tension and wetting ability

#$pands when it free)es


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(ow much freshwater is a&ailable*

About +7% of the earths water is found in

the oceans, -nly . /,/0% of the earthswater is easily a&ailable to us as freshwater2 As we now! this water is recycled! purified! and

distributed &ia the hydrological cycle


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3reshwater resources in the 4"

5ot e&enly distributed and most is polluted by agriculture

and industry

6argest uses of water in the East energy facilities

cooling and manufacturing

6argest uses of water in the West irrigation


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3reshwater resources in the 4"

Problems in the easternUSinclude flooding!occasional urbanshortages! and pollution

Problems in the westernUSinclude watershortages as a result of

low precipitation! highe&aporation! andrecurring drought


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8ain causes of freshwater

shortages

Dry climate

Drought

Water stress


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Ad&antages of dams and reser&oirs

'ontrols floods

8ay produce hydroelectric power

"upply water for irrigation! towns! andcities 9increases the annual runoff

a&ailable for human use by .1:;a$es on water pumped from wells

"et and enforce minimum stream flow

le&els

=i&ert surface water to recharge auifers


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(ow useful is desalination*

>wo widely used methods?2 Distillation

2 Reverse osmosis

Where are most desalinationplants*

What are some disad&antagesto desalination*


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Wasting water

8ost water is lost through e&aporation and

leas

8a@or causes of water waste?

2 6ow costs to water users and supply pro@ects

2 6ac of subsidies for water efficiency


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Wasting less water I

3lood irrigation is the least efficient, 6ow pressurepi&ot and drip systems are the most efficient

Reducing water waste irrigation

2 6ine canals2 Irrigate at night

2Adding water only when:where necessary

2 Polyculture cropping and organic farming

2 4sing water efficient crops2 Irrigating with treated wastewater

2 Importing some crops and meats*


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Wasting less water II

Reducing water waste in industries! homes! andbusinesses2 Redesign manufacturing processes2 6andscape with water efficient plants

2 4se drip irrigation2 Raise water prices2 3i$ leas2 Reuire water conser&ation

2 4se water sa&ing toilets! showerheads! etc,2 Purify and reuse water


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3loodplains and floods

"ome areas ha&e too little water! whileothers sometimes ha&e too much

3loodplains ha&e fertile soil! water forirrigation! flat land! and a&ailability ofwater for transportation and recreation

Benefits of floods?

2 =eposition of nutrientCrich silt2 Recharge groundwater

2 Refill wetlands


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>hree ways in which humans

increase the se&erity of floods

Removing waterabsorbing vegetation

Draining wetlands

iving on flood!lainsand urbani"ation


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(ow can we reduce flood riss*

Straightening and

dee!ening streams

#uilding levees

#uilding dams

Preserving and restoring

wetlands


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What is water pollution*

Any change in water uality that 1< has a

harmful effect on li&ing organisms and:or

0< maes the water unsuitable for desired

uses

2 "ources of pollution?

Point sourcesdischarge at specific locations

$on!oint sourcescannot be traced to any singlesite of discharge


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'ategories of water pollutants

2 Infectious agents 9pathogensaner accidents and offshore blowouts

get most of the publicity

8ost ocean oil pollution comes from

acti&ities on land

2 Burned! dumped! spilled! or leaed onto land

or into sewers


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-il and -ceans? 8echanical methods

&loating booms

S%immer boats

'bsorbent !ads or

mesh !illows


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-il and -ceans? 'hemical methods

Coagulating agents

Dis!ersal agents

&ire


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"ome ways to pre&ent water pollution

Reduce fertili)er runoff to surface water

and leaching into auifers

Plant buffer )ones

Reduce pesticide runoff

'ontrol runoff of animal wastes

Reduce soil erosion and flooding


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3ederal water pollution control

&ederal Water Pollution Control 'ct of

()*+9Clean Water 'ct, ()**-

2 "ets standards for le&els of water pollutants

and reuires permits to pollute

2Adischarge trading !olicy9#PA 1++E< is

designed to use maret forces to reduce

water pollution


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Some bad news under the Clean Water 'ct

8any 4" laes! and ri&ers are still unsafe for

fishing and swimming

(og! poultry! and cattle farms pollute 7/% of 4"

ri&ers 6arge uantities of industrial wastes are dumped

illegally in 4" ri&ers

3ish from many water ways are unsafe to eat Wetlands are still continuing to be lost


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>echnological approaches to the

control of water pollution

Se!tic tan% systems

2 >rap greases and solids and

discharge remaining wastes o&er a

drainage field

Wastewater treatment systems

include.

2 Primarysewage treatment

9mechanical processhe li&ing machine! -berlin 'ollege


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#cologically friendly purification? WetlandCbased

5atural and artificial wetlands

-ften called Hwaste water gardens


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=rining water Ground water may need little to no treatment

>reating 9city< water is similar to wastewater

treatment

2 Waterreser&oirpurification plant

Bottled water

2 8uch more e$pensi&e than tap water2 Bacteria and fungi contaminate ./% of 4"

bottled water

2 >he manufacturing of plastic bottles releases to$ic

gases! liuids! and greenhouse gases

2 8any bottles end up in the landfill2 Bottles are often transported long distances 9lots

of fossil fuels used

Water Quality and Quantity

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