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GroundwaterExists 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
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
http://www.ec.gc.ca/eau-water/default.asp?lang=En&n=300688DC-1
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• Largest aquifer - Ogalla in the Great Plains - lots of water is being withdrawn (problem!)
Cone of Depression a. an area where there is no longer any
ground water b. water table drops too low c. comprises water quality
Saltwater intrusion a. drilling wells along coastline b. rapid pumping lowering water table c. adjacent saltwater infiltrates in
Surface WaterFreshwater that exists above ground - streams, rivers, ponds, lakes, and wetlands
• Rivers a. 3 largest - Amazon in SA - Congo in Africa - Yangtze in China
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
Atmospheric WaterDrought 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
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
Dikes a. built to prevent ocean waters from
flooding adjacent land b. common in Europe – farmland below sea
level
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)
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
Desalination (desalinization) a. removing salt from sea water b. 2 common techniques 1. distillation 2. reverse osmosis - leaves behind a brine (high salt concentration)
http://bcs.whfreeman.com/friedlandapes/#668210__690864__
Water UseFreshwater a. 70% - agriculture 30% - industrial and household
http://www.data360.org/dsg.aspx?Data_Set_Group_Id=757
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)
c. hydroponic agriculture 1. alternative to traditional agriculture 2. crops under greenhouse conditions 3. uses 95% less water than traditional irrigation
http://blog.syracuse.com/cny/2011/01/hydroponic_farming_satisifes_central_new_yorks_craving_for_local_greens_in_midwinter.html
Industry a. in US, ½ water goes towards electricity b. cools machinery (steam) c. refines metals d. used to make paper
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