Water Resources

GEORGIA WATER ISSUES/ TAPPED???

http://www.atlantaregional.com/environment/tri-state-water-wars

http://www.huffingtonpost.com/2013/12/04/water-shortage_n_4378418.html

Will We Have Enough Usable Water?

How much of the Earth’s surface is covered with

water?

• About 70%

How much of that water is freshwater?

• About 2.5% (97.5% is saltwater)

Of the freshwater, how much is ice & glaciers?

• 77.28% (= 1.9% of the earth’s water)

Out of Earth’s Water, less than 1% is accessible

for human use.

Less than 1% is Accessible Fresh Water

0.55% is groundwater

0.01% is in surface water

0.001% is water vapor in the atmosphere

We Manage Water Poorly

Hydrologic cycle: would naturally purify, if we

didn’t overload it and destroy wetlands/forests

•Major forces of purification

•Evaporation

•Infiltration – water

enters soil through

gravity and capillary

action

Problems with water

Water is not distributed evenly

• Haves

• Canada (0.5% world pop. & 20% world supply)

• Have Not's

• China (20% world pop & 7% world supply)

We are managing our water poorly

• We take too much, too fast

• We pollute the water we do have

Global Water Issues

Access to water is

• A global health issue

• An economic issue

• A women’s and children’s issue

• A national and global security issue

Girl Carrying Well Water over Dried Out

Earth during a Severe Drought in India

We Get Freshwater from Groundwater

Ground water: water that sinks into the soil and

is stored in slowly flowing and slowly renewed

underground reservoirs

Zone of saturation: zone where all available

pores in soil and rock in the earth’s crust are

filled by water

Water table: upper surface of the zone of

saturation

Aquifers: porous, water-saturated layers of

sand, gravel, or bedrock that can yield an

economically significant amount of water

More about Aquifers

Aquifers

• Confined: held by impermeable rock layers

• Can create an artesian well & springs

• Unconfined: held by less permeable layers (like clay)

Recharge types – Animation/ Youtube

• Natural recharge (top)

• Lateral recharge (side)

-process by which rainwater

seeps down through the soil into

an underlying aquifer.

Aquifers

Trade-Offs: Withdrawing Groundwater,

Advantages and Disadvantages

Groundwater Overpumping Has Other

Harmful Effects

Limits future food production

Land subsidence

Sinkholes

• sediments that cover buried cavities in the aquifer

systems are delicately balanced by ground-water

fluid pressure

Groundwater overdrafts near coastal regions

• Contamination of the groundwater with saltwater

• Undrinkable and unusable for irrigation

Cone of Depression

Pumping water creates a

“cone of depression” since

water in an aquifer takes so

much time to flow

• Picture yourself drinking a

McDonald’s milkshake… the

shake goes down near the

straw first.

The cone of depression

lowers the water table, which

dries up streams and wells.

More Cone of Depression Images

Land Subsidence & Sinkholes

Land subsidence

is a gradual

settling or sudden

sinking of the

Earth's surface

• Major Causes:

• Groundwater

depletion

• Mining

Basic (gradual) Subsidence

Rapid Subsidence = Sinkhole

Guatemala 2010 – 30 stories deep

Saltwater Intrusion

When groundwater

is removed from the

water table near the

ocean, pressure

forces the salty

water inland, where

it may eventually

infiltrate the well.

Saltwater Intrusion: Solution

Solutions: Groundwater Depletion, Using

Water More Sustainably

Natural Capital Degradation: The Ogallala

is the World’s Largest Known Aquifer

Case Study: Aquifer Depletion in the

United States

Ogallala aquifer: largest known aquifer

• Irrigates the Great Plains

• Water table lowered more than 30m

• Cost of high pumping has eliminated some of the

farmers

• Government subsidies to continue farming

deplete the aquifer further

• Biodiversity threatened in some areas

• https://www.youtube.com/watch?v=XXFsS94HF0

8

Natural Capital Degradation: Areas of

Greatest Aquifer Depletion in the U.S.

Active Figure: Threats to aquifers

US Water Use

Half of our water is from groundwater

Half of our water is from surface water

• Rivers, lakes & reservoirs

When you remove groundwater, you deplete

surface water as well…why??

We Get Freshwater from Surface Water

Surface Water: precipitation that does not infiltrate the ground or return to the atmosphere by evaporation or transpiration

• Surface runoff: water flowing off the land into bodies of surface water

• Watershed (drainage) basin: land area that delivers water, sediment, and dissolved substances via small streams to a major stream (river)

• Reliable runoff: surface runoff of water that generally can be counted on as a stable source of water from year to year

• 1/3 of total

We Use a Large and Growing Portion of

the World’s Reliable Runoff

In the last century, human population tripled and

water withdrawal increased sevenfold

More water used by the rich

• It takes 2,400 bathtubs to make a small car (120,000 gal)

• 37 gallons to produce 1 cup of coffee

• 25 bathtubs to make 1 T-shirt

Case Study: Freshwater Resources in the

United States

We have more than enough renewable

freshwater, but it is unevenly distributed

TRIVIA

What's the rainiest city in the US?

• For the last 30 years, the rainiest 3 in order are:

• Mobile, AL

• Pensacola, FL

• New Orleans, LA

Average Annual Precipitation in U.S.

Water-Deficit Regions in U.S.

Shown for proximity purposes

Case Study: Freshwater Resources in the

United States

In the east

• Water is used for:

• Energy production, manufacturing

• Water problems are:

• Flooding

• Urban shortages due to pollution

• Occasional Drought

• A prolonged period in which precipitation is at

least 70% lower and evaporation is higher than

normal

Case Study: Freshwater Resources in the

United States

In the west

• Water is used for:

• Irrigation (85%)

• Water problems are:

• Shortage due to low precipitation, evaporation and

recurring drought

2007: U.S. Geological Survey projection

• Water hotspots: places where competition for

scarce water could trigger political and legal

conflicts in the next 20 years (36 states)

Water Hotspots in 17 Western U.S. States

Natural Capital Degradation: Stress on

the World’s Major River Basins

Long-Term Severe Drought Is Increasing

Causes

• Extended period of below-normal rainfall

• Diminished groundwater

Harmful environmental effects

• Dries out soils

• Reduces stream flows

• Decreases tree growth & biomass

• Lowers NPP & crop yields

• Shifts biomes (desertification)

Building More Dams

Main goals of a dam and reservoir system

• Capture and store runoff

• Runoff is released to control floods

• Dams are also used for/to

• Generate electricity

• Supply irrigation water

• Recreation (reservoirs)

Advantages and Disadvantages of Large

Dams and Reservoirs

The Ataturk Dam Project in

Eastern Turkey

Some Rivers Are Running Dry and Some

Lakes Are Shrinking

Dams disrupt the hydrologic cycle

Major rivers running dry part of the year

• Colorado and Rio Grande, U.S.

• Yangtze and Yellow, China

• Indus, India

• Danube, Europe

• Nile River-Lake Victoria, Egypt

Lake Chad Africa: disappearing

Water Transfers

CA, U.S., Transfers Water from Water-Rich

Areas to Water-Poor Areas

• Water transferred by

• Tunnels

• Aqueducts/Canals

• Underground pipes

• May cause environmental problems

Removing Salt from Seawater Seems

Promising but Is Costly (1)

Desalination

• Distillation (boiling, condensing)

• Reverse osmosis (sending water through a

filtration system using pressure to go against

typical osmosis force)

15,000 plants in 125 countries

• Saudi Arabia: highest number

Removing Salt from Seawater Seems

Promising but Is Costly

Problems

• High cost and energy footprint

• Kills many marine organisms and algae

• Large quantity of brine wastes

• super concentrated by-product that results from

treating brackish water or seawater

Water Use

Who uses the most water?

#1 #2 #3

AGRICULTURE INDUSTRY MUNICIPAL (Household)

70% 10%20%

In Water-Short Areas Farmers and Cities

Compete for Water Resources

Some countries import grain to free up water

2007: National Academy of Science study

• Increased corn production in the U.S. to make

ethanol as an alternative fuel

• Decreasing water supplies

• Aquifer depletion

• Increase in pollution of streams and aquifers

Natural Capital Degradation: Irrigation in

Saudi Arabia Using an Aquifer

Using Water More Sustainably

Water Waste:

• Worldwide 65 – 70% of water used is wasted

• Evaporation, Leaks, misuse

We Can Cut Water Waste in Irrigation

Flood irrigation

• Wasteful

Center-pivot, low pressure sprinkler

Drip or trickle irrigation, microirrigation

• Costly; less water waste

Major Irrigation Systems

Solutions: Reducing Irrigation

Water Waste

Hydroponic Agriculture

The cultivation of crops in

greenhouse conditions with

roots fed a nutrient rich

solution, but no soil.

• Water not taken up is

reused

• Takes 95% less water

• Higher yields per hectare

• Vertical growing capacity

• Year round conditions

We Can Cut Water Waste in Industry

and Homes

Recycle water in industry

• Especially in energy generation (steam)

Fix leaks in the plumbing systems

Use water-thrifty landscaping: xeriscaping

Use gray water: waste water from baths,

showers, bathroom sinks, & washing machines

Water saving fixtures

Outside the Home

Xeriscaping – low water landscaping

Use native vegetation that can survive local

climate without additional water

New Mexico Georgia

What Can You Do? Water Use and Waste

How do you use your water?

For the average American:

• 41% Toilet Flushing

• 32% Bathing

• 21% Laundry

• 5% Cooking and Drinking

Is your toilet water too clean?

Using Gray Water Composting Toilet

Case Studies

Case Study: The Colorado River Basin—

An Overtapped Resource

Supplies water and electricity for more than 25

million people

• Irrigation of crops

• Recreation

Four Major problems

• Colorado River basin has very dry lands

• Modest flow of water for its size

• Legal pacts allocated more water for human use

than it can supply

• Amount of water flowing to the mouth of the river

has dropped

The Colorado River Basin

Aerial View of Glen Canyon Dam Across

the Colorado River and Lake Powell

The Flow of the Colorado River Measured

at Its Mouth Has Dropped Sharply

Case Study: China’s Three

Gorges Dam

World’s largest hydroelectric dam and reservoir

• 2 km long across the Yangtze River

Benefits

• Electricity-producing potential is huge

• Holds back the Yangtze River floodwaters

• Allows cargo-carrying ships

Case Study: China’s Three

Gorges Dam - Problems

Harmful effects

• Displaces about 5.4 million people

• Built over a seismic fault

• Significance?

• Rotting plant and animal matter producing CH4

• Worse than CO2 emissions

• Will the Yangtze River become a sewer?

The California Water Project and the

Central Arizona Project

Case Study: The Aral Sea Disaster

Large-scale water transfers in dry central Asia

Salinity

Wetland destruction and wildlife

Fish extinctions and fishing

Wind-blown salt

Water pollution

Climatic changes

Restoration efforts

Natural Capital Degradation: The Aral

Sea, Shrinking Freshwater Lake

Ship Stranded in Desert Formed by

Shrinkage of the Aral Sea