Презентация на тему Water Resources

Environmental Geology Chapter 11 - Water Resources

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Introduction to Water Resources

A person can live 1 – 2 weeks w/out water
Human body is 70% water
Food plants / crops need water
Oxygen result of photosynthesis
Water used for manufacturing, producing concrete, and electricity
Water use in homes, landscaping
Population growth increases demand for fresh water

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Origin of Earth’s Water

Large meteor impact on Earth ejected debris and formed the Moon
Then melting occurred, volcanic activity
Volcanic gases plus comet impacts formed atmosphere rich in water vapor
Planet cooled, water condensed and rain fell forming oceans
Tectonic activity allowed land masses to rise above sea level and oceans became deeper

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Hydrologic Cycle

Continual and cyclic transfer of water between oceans, fresh water bodies, atmosphere and land
Driven by solar radiation which causes evaporation
“The Water Cycle II” – MySTAR > Library tab > Films on Demand

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Hydrologic Cycle – Figure 11.1

pH – Process of Hydrogen

pH scale is logarithmic; each step up is 10 fold
Water flowing out of abandoned mines about 2 pH
Pure water is 7 pH
Normal rainfall 5.6 pH due to CO2 in atmosphere
Heavy metals more toxic as acidity increase

https://water.usgs.gov/edu/ph.html

Salinity

Amount of electrically charged ions (salts) dissolved in water
Fresh water:
Few dissolved ions
Produced by evaporation (salts left behind)
Salt water (marine) – highly saline; 35,000 mg/L
Brackish – varying levels of salinity, where fresh water meets marine

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Fresh Water in Limited Supply

2.8% of planet’s water is fresh
77.4% of fresh water is locked up in glacial ice
22.1% is ground or subsurface water
0.5% surface water
Fresh water is not evenly distributed across Earth
Supply varies seasonally and throughout geologic time

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Figure 11.2 Page 330

Table 11.1 Page 330

Human Use of Freshwater

Large increase following Industrial Revolution
Use for manufacturing, producing energy, flushing toilets
Agricultural irrigation
Withdrawals have declined and remained steady since 1980s due to more efficient use

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Use of Fresh Water

Consumptive – water is lost or consumed
City or municipal
Electricity generation
Personal
Irrigation – water lost due to evaporation and transpiration
Non-consumptive
Washing dishes – almost all water returned to a water supply source
Off stream use – water withdrawn from one source and returned to a different source
Consumptive and off stream can disrupt natural systems

Surface Water Resources

River and streams – collect precipitation and transport it to ocean
Some infiltrates in to groundwater
Water table – depth where porous materials are completely saturated
Romans used aqueduct system
California uses aqueducts to deliver water to L.A.
Impact of water withdrawal versus where it is discharged

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Supply of Freshwater

Unsustainable use harming natural systems and beginning to limit growth and development of human populations around world
Five options when faced with water shortages:
Increase storage, build reservoirs
Transport water from other sources
Conservation programs
Nontraditional sources
Voluntarily limit growth

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Lakes and Reservoirs

Natural lakes relatively rare
Reservoir created when rivers are dammed to create an artificial lake upstream; stockpile of large amount of freshwater; dam assists flood control
Negative impacts: floods large area upstream, no or less sediment transported downstream, more evaporation

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Groundwater Resources

Groundwater – water that resides with the void or pore space of subsurface materials
Three factors determine if groundwater is a viable source:
Quantity – depends on porosity
Ease of withdrawal – hydraulic conductivity and permeability
Quality

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Groundwater

Types of Aquifers

Aquifer – water bearing rock or sediment layer that readily transmits water; hydraulic conductivity is high
Aquitard – low conductivity, clay rich sediment, shales, unfractured crystalline rocks; “confining layers”
Unconfined aquifer – highly conductive, open to atmosphere and surface waters
Confined aquifer – overlain by aquitard, sealed off from surface

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Groundwater

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Movement of Groundwater

Hydraulic head
Height of water table or potentiometric surface – height water will rise; measure of potential energy in confined aquifer
Hydraulic gradient
Slope or steepness of water table

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Movement of Groundwater

Groundwater Recharge

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Process by which aquifers are replenished by infiltrating water that ends up at the water table

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More Groundwater Sources

Springs – groundwater discharges at the surface
Mineral – high salinity
Warm water/hot water
Water wells and drawdown cones
Modern wells – small hole drilled into subsurface, well casing lowered into well and submersible pump brings water up; most are 50 – 100 feet deep
Cone of depression - caused by pumping action of well in water table or potentiometric surface; can reverse direction of water flow

Springs

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Draw Down

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Impacts of Groundwater Withdrawals

May resort to groundwater mining (Tucson, AZ)
Dry wells
Land subsidence (Mexico City)
Increased well costs
Reduced spring and stream flow
Saltwater intrusion

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Selecting a Water-Supply Source

Groundwater
River
Reservoir

Case Study 11.1 Page 346

Ogallala Aquifer of western U.S.
Groundwater mining allowed this area to be major grain producer
Semi arid region receives <16 inches rain/year to 28 inches/year
Transpiration prohibits much infiltration
Groundwater levels reduced by 200 feet

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Alternative Sources

Desalinization – removing salts or dissolved ions from sea water
Sea water is 35,000 mg salt/L and must be 500 mg/L to be safe for humans
Distillation – salt water boiled and water vapor captured
Reverse osmosis – semi-permeable membrane traps salts and allows H20 molecules to pass
Problem with disposing of super saline waste water
Expensive, only used in areas with acute water supply problems

Alternative Sources

Reclaimed/recycled
Municipal wastewater recycling – can be treated to be safe to drink
Reclaimed water not safe for drinking can be used for irrigation or industrial use – cost savings over using drinking water
Mixing treated waste water with normal water to go through natural processes then filtration and treatment resulting in drinking water

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Alternative Sources

Industrial and domestic recycling
Non contact cooling water – reusing water used as a coolant as temperature changes does not contaminate it
“Graywater” – home waste water that has not been used in a toilet can be collected and reused

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Alternative Sources

Aquifer storage and recovery – storing excess surface water in an aquifer
Rain water harvesting
Underground or above ground cistern

Conservation

Use water more efficiently, more sustainably
2 basic categories - engineering practices and behavioral practices
Domestic and commercial users – largest use of water for irrigating lawns and landscaping
Xeriscaping – use native plants adapted to local climate
Efficient appliances
Municipal supply systems
Education, repair leaks, fees based on usage
Agriculture – better practices
No till farming
Contour plowing
More efficient irrigation

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20 Ways to Conserve Water in Your Home

1. Shower Bucket. Instead of letting the water pour down the drain, stick a bucket under the faucet while you wait for your shower water to heat up. You can use the water for flushing the toilet or watering your plants.
2.  Turn off the tap while brushing your teeth. Water comes out of the average faucet at 2.5 gallons per minute. Don’t let all that water go down the drain while you brush! Turn off the faucet after you wet your brush, and leave it off until it’s time to rinse.
3. Turn off the tap while washing your hands. Do you need the water to run while you’re scrubbing your hands? Save a few gallons of water and turn the faucet off after you wet your hands until you need to rinse.
4. If it’s yellow, let it mellow. This tip might not be for everyone, but the toilet is one of the most water-intensive fixtures in the house. Do you need to flush every time?

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5. Fix your leaks. Whether you go DIY or hire a plumber, fixing leaky faucets can mean big water savings.
Re-use your pasta cooking liquid. Instead of dumping that water down the drain, try draining your pasta water into a large pot. Once it cools, you can use it to water your plants. Just make sure you wait, because if you dump that boiling water on your plants, you might harm them.
7. Head to the car wash. If you feel compelled to wash your car, take it to a car wash that recycles the water, rather than washing at home with the hose.
8. Cut your showers short. Older shower heads can use as much as 5 gallons of water per minute. Speed things up in the shower for some serious water savings.
9. Choose efficient fixtures. Aerating your faucets, investing in a low-flow toilet, choosing efficient shower heads, and opting for a Water Sense rated dishwasher and washing machine can add up to big water savings.

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10. Shrink your lawn. Even better: lose the lawn completely. Instead, opt for a xeriscaped landscape that incorporates water wise ground cover, succulents, and other plants that thrive in drought conditions.
11. Don’t run the dishwasher or washing machine until they’re full. Those half-loads add up to gallons and gallons of wasted water.
12. Keep an eye on your bill to spot leaks. If your water bill spikes suddenly, there’s a good chance that a leak is the culprit. Call in a plumber to check your lines to save water and cash!
13. Install a rain barrel. Rainwater harvesting is a great way to keep your plants hydrated without turning on the hose or sprinkler.

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14. Flush with less. Older toilets use a lot of water. You can reduce your usage by sinking a half gallon jug of water in the toilet tank. Do NOT use a brick, because it will break down and the sediment can damage your tank.
15. Water in the early morning. You’ll need less water, since cooler morning temperatures mean losing less water to evaporation. It’s not a great idea to water in the evenings, since this can promote mold growth.
16. Hand-washing a lot of dishes? Fill up your sink with water, instead of letting it run the whole time that you’re scrubbing.

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17. Use less electricity. Power plants use thousands of gallons of water to cool. Do your part to conserve power, and you’re indirectly saving water, too!
18. Wash Fido outdoors. That way, you’re watering your yard while you’re cleaning your pup. Just make sure that the soap you’re using isn’t harmful to your plants!
19. Skip the shower from time to time. Do you really need to shower multiple times a day or even daily? Skipping even one shower a week adds up to big water savings.
20. Re-use grey water. Check to make sure that this is legal where you live, but in some areas you can do things like re-route the runoff from your clothes washer and use that water for things like flushing the toilet.
http://www.care2.com/greenliving/20-ways-to-conserve-water-at-home.html

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