Chapter 14 Notes:

Three most serious Environmental Problems of this century:

  1. Water shortages
  2. Biodiversity loss
  3. Climate Change

How much water is available?

  1. A new appraisal shows that of the total 1386 million km3 of water (Earth's hydrosphere)
  2. 97.5% is saltwater, e.g., oceans, seas
  3. 2.5% is freshwater (54.65 million km3)

Freshwater comes from different sources:

  1. The greater portion of the freshwater (68.7%: 37.4 million km3) is in the form of permanent ice (Arctic, Antarctic, alpine mountain ranges, etc.)
  2. 29.9 % of the freshwater (16.24 million km3) is ground water, mostly deep seated
  3. Only 0.26% (or, 64,000 km3)of the total freshwater is in lakes, river systems, etc. and it is accessible for our needs. In fact, the total water withdrawals worldwide is less than 5000 km3 or about one tenth of the total river discharge -- a mere drop of Earth's waters

Aquifer- Underground water (two types= Confined & Unconfined)

Ogallala aquifer- Central U.S.

How is water used?

  • 70% Irrigation
  • 20%Industry
  • 10% Cities & Residence

East Coast

  • Major usage is energy production, cooling & manufacturing
  • Problems- flooding, occasional urban shortages & pollution

Western US

  • Major use is Irrigation (85%)
  • Problems- shortage of runoff water (rivers running dry), high evaporation & prolonged drought

Too Little Water!

41% of people live in river basins that do not have enough fresh water!

Why?

  1. dry climate
  2. Drought
  3. Too many people using and wasting water
  4. Lack of money to

  1. drill deep wells and build storage

Know the advantages & disadvantages of privatizing water (pg 311 & 312)

Withdrawing Groundwater- know adv. & disadv (fig 14-7 pg 313)

Over-withdrawing groundwater

  1. Land subsistence (sink holes)
  2. Contaminate water with salt water (coastal)
  3. Water will not be replaced if it is confined aquifer

Dam those Dams!

Dam Removal:

Adv:

  • Let rivers run free again
  • Restore river ecosystems, establish economically important fisheries and
  • Foster river recreational activities.

Disadv:

  • Costs for taxpayers are high
  • Removing a dam can expose downstream water users to toxic sediments
  • Lack of flood control

Transfer of Water

Adv:

  • Can make unproductive areas more productive
  • Strengthen economics in area water is brought

Disadv:

  • Encourages unsustainable water use

California Water Project

  • Largest water transfer in world
  • Transfers water to water poor areas in So. Cal
  • Water transfer has negative impacts on No. Cal.

Solutions:

  1. improve irrigation efficiency,
  2. Stop growing water thirsty crops
  3. Increase price of water now sold to farmers- a lot of farmers are paying low prices for water because they purchased long term water rights along time ago.
  4. Allow farmers to sell rights to water withdraw

Aral Sea Disaster:

4th largest FW lake in world (located in Russia)

Problems caused:

  1. Reduced the lake to 10% of original volume.
  2. Two rivers to sea now a trickle
  3. 85% of wetlands gone
  4. ½ local bird & mammal species gone
  5. Human made desert covered with salt.
  6. 20 of 24 native fish species extinct
  7. Devastated areas fish industry
  8. Salt from desert blows with wind & chokes people, pollutes water, kills wildlife & Crops.
  9. Altered climate

Desalting Water

  • Two methods- Distillation & Reverse Osmosis
  • Provides .3% of worlds FW – mostly in Saudi Arabia
  • Two expensive for large scale use
  • Produces salt waste that needs to be disposed of

Cloud seeding:

Problems

  • Does not work well in areas most needed (dry)
  • Some studies say it does not work at all
  • Chemicals could possibly be harmful
  • Legal disputes (cloud rustling)

Waste not Want not!

  • 65 to 70% loss due to evaporation or leaks & waste.
  • We need to reduce this to 15%
  • US is at 50% due to less waste by farmers, industry & at home

Biggest problem-

#1-water is too cheap so people waste it. No incentive to conserve & invest in ways to conserve better.

#2-lack of subsidies that promote water conservation

Irrigation:

  • Flood irrigation or Gravity Flow Irrigation is very wasteful (60 to 80% efficient)
  • Center Pivot/Low pressure sprinkler- 80% to 95% efficient
  • Drip irrigation 90-95 % efficient

Farmers would use drip irrigation if

  • More expensive water
  • Gov’t subsidies for water conservation

Solutions to Reducing Irrigation Water Waste:

  1. Line canals
  2. Level fields w/ lasers
  3. Irrigate at night (reduce evap)
  4. Monitor soil moisture and only water when needed.
  5. Polyculture
  6. Organic farming
  7. Don’t grow water thirsty crops
  8. Use drought or salt resistant crops
  9. Irrigate with urban waste water

Reducing Water Waste:

  1. Redesign manufacturing processes
  2. Repair leaking underground pipes
  3. Landscape year with plants that use little water
  4. Use drip irrigation
  5. Fix water leaks
  6. Use water meters
  7. Raise water prices
  8. Use waterless toilets
  9. Require water conservation
  10. Use water saving toilets, showerheads, cloth & dish washers
  11. Purify and resuse water for houses
  12. Capture and use roof water

Use Less water to remove wastes:

  • Copy Nature- reuse don’t waste!
  • Use sewage water to fertilize non-food vegetation
  • Ban discharge of industrial toxic chemicals into sewage water
  • Use waterless toilets (compost fecal matter)

Flood Plains:

  • Popular for humans because very productive & lots of water
  • Naturally reduce flooding
  • Highly productive wetlands
  • Maintain high water quality
  • Recharge groundwater

To protect people on flood plains

  • Rivers have been narrowed (channelized)
  • Dammed to store water & prevent flooding

Flooding is increasing because of

  1. Removal of water-absorbing vegetation (particularly on hillsides)
  2. Replacement of vegetation with roads, parking lots & buildings
  3. Draining & building on wetlands

We can use water more sustainably by cutting waste, raising water prices, preserving forests and wetlands in water basins, and slowing population growth. A blue revolution to conserve water would include a mix of several components:

1.Expand and improve monitoring of river flows.

2.Overhaul water policy to protect forests etc.

3.Regulate withdrawals to prevent aquifer depletion.

4.Leave enough water in rivers to protect wildlife.

5.Remove government subsidies that cause water to be underpriced.

6.Switch to waste-treatment systems that accept only nontoxic wastes.

7.Get very serious about slowing global warming.

8.Slow population growth.

What can you personally do?

  1. Use water saving toilets, showers, appliances
  2. Shower instead of baths
  3. Stop water leaks (put die in toilet)
  4. Waste less while washing/brushing
  5. Flush toilets occasionally
  6. Eat less beef
  7. Wash full loads
  8. Use recycled water for lawns, gardens, plants & cars
  9. Replace lawn with native plants that need little water
  10. Water lawns before/after sun
  11. Don’t hose to clean (sweep)
  12. Use drip irrigation