1. Water Resources
Chapter 9

2. Water as a Resource 70% of earth’s surface is covered by water
97-98% is found in the oceans as salt water
Less than 3% is freshwater and the majority of the freshwater is found in ice and glaciers and the rest resides underground

3. Groundwater Exists in aquifers (permeable layers of rock and sediment)
a. confined aquifer
b. unconfined aquifer
Water table
a. uppermost level where water still saturates rock or soil
b. “surface of the groundwater”
Groundwater recharge
Groundwater recharge – where water goes through the soil and works it way into the aquifer

4. - water naturally rises to the ground surface b. artesian wells
Sources of aquifers
a. springs
- source of freshwater
- water naturally rises to the ground surface
b. artesian wells
- drilling in confined aquifer
- releases pressure on the water
* Springs serve as a major source of freshwater for aquatic biomes and a source of drinking water for humans

5. Problems with water from unconfined aquifer - recharge very quickly
- contamination with chemicals
Largest aquifer
- Ogalla in the Great Plains
- lots of water is being withdrawn (problem!)
May recharge with water that fell from the ground last night or last year whereas recharge in confined aquifers is very slow, 10-20,000 years therefore is it much older and less contaminated

6. Cone of Depression
a. an area where there is no longer any ground water
b. water table drops too low
c. comprises water quality

7. a. drilling wells along coastline
Saltwater intrusion
a. drilling wells along coastline
b. rapid pumping lowering water table
c. adjacent saltwater infiltrates in
Rapid pumping reduces the water pressure in the aquifer allowing the saltwater to move in and contaminate the water with salt

8. Surface Water Freshwater that exists above ground
- streams, rivers, ponds, lakes, and wetlands
Rivers
a. 3 largest
- Amazon in SA
- Congo in Africa
- Yangtze in China
Rivers – measured by the volume of water they carry

9. b. land surrounding rivers is typically fertile
c. floodwaters deposit nutrient-rich sediment onto the
floodplain
Lakes
a. classified by level of primary productivity
b. oligotrophic v. eutrophic
Wetlands
a. control flooding
Lakes – depressions in the earth’s surface that are filled by precipitation, runoff that is not absorbed from surrounding areas and groundwater
Oligotrophic – low productivty due to low amounts of nutrients such as phosphorus
Eutrophic – high level of productivity

10. Atmospheric Water Drought a. long-term effects on soil Flooding
a. water input exceeds the ability of an area to absorb
the water
b. areas affected by drought-impermeable surfaces-
flood
Essential to global water distribution
Drought
Drys out soil – loss of soil fertility
Soil may become harden and impermeable causing water to runoff and eroding the topsoil in the process

11. Altering the Availability of Water
Levees
a. enlarged bank built up on each side of the river
b. Mississippi River – largest system of levees
c. major challenges
- floodwater no longer add fertility to floodplain
- sediments will deposit further down where river
meets ocean
- cause even worse flooding downstream
- can collapse
* Preventing flooding in order to use the floodplain for commercial and residential use

12. Dikes
a. built to prevent ocean waters from flooding
adjacent land
b. common in Europe – farmland below sea level

13. Dams
a. barrier that runs across the river or stream to control
the flow of water
b. reservoir
c. used to generate electricity
d. world’s largest – Three Gorges Dam in China
e. environmental problems
- interruption of natural flow of water (fish ladders)

14. a. canals/ditches used to carry water from one place to another
Aqueducts
a. canals/ditches used to carry water from one place to
another
b. concrete canals and pressurized steel pipes
c. In the US: NYC and LA
d. ensures clean water, but disturbs habitats
e. diversion project
- Soviet Union diverted two rivers that fed into the Aral
Sea
Typically water is removed from a lake or river and transported to wherever it is needed
Earlier ones were made up of limestone
NYC uses the aqueduct in the Catskills and LA gest their water from the Colorado River
Diverting water also means that there is now less water where there used to be more
Can result in a lower flow of freshwater into estuaries, meaning more ocean water moves farther up the river, increasing the salinity of the estuary harming aquatic life (example: India and Bangledesh)
Diversion project
- reduced the amount of freshwater into the aral sea, increasing salinity
- reduced the surface area of the sea which in turn affected the local climate

15. Desalination (desalinization) a. removing salt from sea water
b. 2 common techniques
1. distillation
2. reverse osmosis
- leaves behind a brine
(high salt concentration)
water-poor countries way of obtaining fresh water
Distillation
- heat water to a boil, leaving the salt behind as a precipitate
- steam that is produced is captured and condensed, resulting in pure water
- requires lots of energy
Reverse osmosis
- water is forced through a thin semi-permeable membrane at high pressure
- water can pass through, but salt cannot
- newer and often less costly
- brine (returned to open ocean), could harm soil, plant life and animal life

16. Water Use Freshwater a. 70% - agriculture
30% - industrial and household
Proportion varies from person to person and country to country

17. b. US: 1/3 of freshwater is used for irrigation
Agriculture
a. largest use of water
b. US: 1/3 of freshwater is used for irrigation
1. furrow – 65% efficient
2. flood – 70-80% efficient
3. spray – 75-95% efficient
4. drip – over 95% efficient (reduces weed growth)
together, india, china, us and pakistan account for more than half of the irrigated land in the world
Furrow – oldest technique; farmer digs a trench along the crop row and fills them with water to provide moisture for the plant roots
Spray – more expensive; water pumped from a well into an apparatus that has nozzles to spray the entire field
Drip – reduces weeds by keeping the surface soil dry and discouraging weed germination

18. c. hydroponic agriculture 1. alternative to traditional agriculture 2
c. hydroponic agriculture 1. alternative to traditional agriculture 2. crops under greenhouse conditions 3. uses 95% less water than traditional irrigation
Roots are emersed in nutrient-rich solution, not soil
Can grow things anytime of the year since it is a controlled setting

19. a. in US, ½ water goes towards electricity b. cools machinery (steam)
Industry
a. in US, ½ water goes towards electricity
b. cools machinery (steam)
c. refines metals
d. used to make paper
Electricity
Some water is consumed when making electricity, some is not
Cooling machinery
Plants use heat to convert water to steam

20. a. in US, 10% water used in homes b. Indoor use
Household
a. in US, 10% water used in homes
b. Indoor use
1. flushing toilets (41%), bathing (33%), laundry
(21%), and cooking/drinking (5%)
c. Outdoor use
1. watering lawns, washing cars, etc.
d. drinking water
Where we live, determines the amount of water that is used daily by the average person
Drinking water
More than 1 billion people lack access to clean drinking water.
1.8 million people die due to diarhheal diseases because of contaminated drinking water, most are childrean

21. Water Conservation A NECESSITY!
Improved efficiencies in toilets and shower heads
Plant vegetation that’s appropriate for your climate
a. Las Vegas, Nevada