Water Flashcards
1
Q
Nile
A
-shared by 10 countries
-most water used by Egypt, Sudan,
and Ethiopia
-Egypt gets more than 97% of
water from Nile and last in line
-must import 40% of grain to feed
growing population
-Ethiopia and Sudan plan to divert
more water from the Nile ->
decreased water availability in
Egypt
- Egypt’s options:
> go to war w/ Sudan & Ethiopia
> cut population growth
> increase irrigation efficiency
> work out water sharing agreements
2
Q
Tigris-Euphrates
A
-shared by turkey, Syria, and Iraq
- turkey:
> at headwaters -> controls flow
downstream
> building 24 dams to generate
electricity for irrigation
> will reduce flow by 35% or more
- Syria plans to build dams -> less
water for Iraq -> may lead to war
between Syria and Iraq
3
Q
Jordan
A
- most water - short region
- share by Jordan, Syria, and Israel
- population in area expected to
double by 2050 - 1994: Israel and turkey signed a
treaty which turkey will supply
Israel with water in exchange for
weapons - Syria plans to build dams -> Israel
threatened to destroy dams
4
Q
Waters Importance
A
- oceans help regulate climate
- oceans dilute and degrade wastes
- oceans provide habits for many
species - organisms are made up mostly of
water - water used in:
> agriculture
> manufacturing
> transportation
5
Q
Surface water
A
- surface runoff - rivers, lakes, reservoirs - watershed (drainage) basin - reliable runoff - 1/3 of total (2/3 lost by seasonal floods)
6
Q
Groundwater
A
- zone of saturation
- water table
- aquifers - porous, water -
saturated layer of groundwater
that can be economically used - natural recharge - replenished
from the side by nearby streams
7
Q
Aquifers
A
- if rate of withdrawal > rate of
renewal…
> salt-water intrusion may occur
in coastal areas
> depletion of aquifer may result
in decreased flow of rivers and
streams fed by aquifer - fossil aquifer
> gets very little recharge on a
human scale
> considered a non-renewable
resource
> “water mining” - withdrawal of
large amounts is water from
ancient water deposits
8
Q
Case study: freshwater resource in the USA
A
- Western USA - water poor
> too little precipitation
> groundwater
> large use: irrigation (85%)
> water problems
-> shortage of runoff
-> prolonged drought
-> decreased water table
(sinkholes)
- Eastern USA - water rich
- ample precipitation
- surface water
- largest use:
-> energy productivity
-> cooling
-> manufacturing
- water problems
-> flooding
-> occasional shortage
-> pollution
( ex. 3 million Long Island NY
residents rely on and
increasingly contaminated
aquifer)
9
Q
World Statistics
A
- 2002 UN report: > 500 million people live in water stressed/ water scarce areas -> projected to increase to 2.4 - 3.4 billion people by 2025 - china: water supply can only support 50% of it's current population - water shortages will cause: > decreased food production > decreased economic growth and development - 1 out of 6 people - no regular access to clean water and live in hydrological poverty > cannot afford safe, clean water > do not have municipal water supply and most use unsafe water or buy water
10
Q
Human activities worsen flooding
A
- urbanization > paving and building -> increase runoff - draining wetlands (that absorb floodwaters) - removal of water - absorbing vegetation on hill slopes - increased population living on floodplains
11
Q
Channelization: reducing flooding risks
A
- the straightening, widening, and
deepening of a stream
> advantages:
-> decreased upstream flooding
> disadvantages:
-> can increase bank erosion
(due to increased velocity)
-> can increase downstream
flooding
-> can increase sedimentation
downstream
-> \$\$$
12
Q
Levees
A
- increase streams capacity to hold
water
> advantages:
-> decreased flooding
> disadvantages:
-> false sense if security ->
people build too close
-> if water breeches levee ->
cannot recede -> areas stay
underwater longer
13
Q
Identify and manage flood-prone areas
A
- zoning laws:
> examine historical records and
create flood frequency/flood
hazard maps
> ban buildings in high risk zones
> elevated buildings
> construct a flood way that
allows water to flow through a
community with minimal
damage
14
Q
Stream Pollution
A
- natural recovery processes
> can recover rapidly from
degradable, oxygen- demanding
wastes or excess heat by a
combination of dilution and
bacterial decay
15
Q
Resolving water distribution problems requires:
A
- regional cooperation
- decreased population growth
- increased efficiency in water use
- higher water prices
- increased grain imports
- improvements in irrigation
16
Q
Water’s Unique Properties
A
- liquid water exists over a wide
temperature range
- water filters out UV -> protects
aquatic organisms
- water's high specific heat ->
change temperature slowly
> helps protect organisms from
abrupt temperature changes
> moderates climate
> excellent coolant
- superior solvent - can dissolve
many compounds
> carry dissolved nutrients into
tissues in organisms
> flush wastes out if tissues
> all-purpose cleanser
> note: this property of water
causes it to become easily
polluted
- E-X-P-A-N-D-S as it freezes -> ice
floats and life can continue in
ponds and lakes during cold
winter months
17
Q
Flowing Artesian Wells
A
- ordinary well:
> needs energy to extract
> unconfined aquifer - more likely
to be polluted
- wells A & B
> flowing artesian wells: flow
under their own natural pressure
> confined aquifer - less likely to
be polluted because of small
recharge area
18
Q
World Average Water Use
A
70% - water withdrawn is used for
agricultural reasons (typically
irrigation)
20% - water withdrawn is for
industrial use
10% - water withdrawn is used for
residential use
19
Q
Case Study: Freshwater Resources in USA
A
- USA has enough water for
everyone, but much is in the
wrong place at the wrong time
20
Q
Water Hot Spots in Western States
A
- water hot spots in 17 USA western states that, by 2050, could ave intense conflicts over scarce water needed for urban growth, recreation, and wild life
21
Q
Freshwater Shortages
A
- dry climate/aridity
- drought
> a period of 21 days (or longer) in
which precipitation is at least
70% lower than normal - desiccation
> drying of exposed soil due to
deforestation, overgrazing - water stress
> low per capita availability (due
to increased population relying
on fixed supply)
22
Q
Hydrological Poverty
A
- developed countries have the
ability to bring water into needed
areas
- developing countries, the people
are forced to live where the water
is
> water quality may decline from
animals
> improper disposal of waste
> water for bathing may also be
water for drinking
23
Q
Solutions: Increasing Freshwater Supplies
A
- dams
- watershed transfer
- tapping groundwater
- desalination
- water conservation/curbing waste
24
Q
Trade-offs of Large Dams and Reserviors
A
- provides irrigation water above and below
dam - provides water for drinking
- reservoir useful for recreation and fishing
- can produce cheap electricity (hydro-
power) - reduces downstream flooding
- flooded land destroys forests or cropland
and displaces people - $$$ to build
- large losses of water through evaporation
- deprives downstream cropland and
estuaries of nutrient rich soil - risk of failure and devastating downstream
flooding - disrupts migration and spawning of some fish
25
Q
Case Study: China’s Three Gorges Dam
A
- “Great Wall across the Yangtze”
- will be the world’s largest hydroelectric
dam and reservoir
> dam - 1.2 miles long
> reservoir - 370 miles long - will be completed in 2013
- cost $25 billion
- will displace 1.9 million people
- will generate the electrical equivalent of 20
coal pr nuclear power plants - will decrease downstream flooding (which
has killed 500,000 people during past 100
years)
26
Q
TRADE OFFS
China’s Three Gorges Dam
A
-advantages
> will generate about 10% of china's
electricity
> reduces dependence on coal
> reduces air pollution
> reduces CO2 emissions
> reduces chances of downstream flooding
for 16 million people
> reduces river sitting below dam by
eroded soil
> increases irrigation water for cropland
below dam
- disadvantages
> floods large areas of cropland and
forests
> displaces 1.9 million people
> increases water pollution because of
reduced water flow
> reduces deposits of nutrient-rich
sediments below dam
> increases saltwater introduced into
drinking water near mouth of river
because of decreased water flow
> disrupts spawning and migration of
some fish below dam
> high cost
27
Q
Case Study: Aral Sea Disaster
A
- large-scale water transfers in dry central
Asia (Uzbekistan and Kazakhstan - former
Soviet Union) - since 1960, water was diverted from Aral
sea and 2 feeder rivers for irrigation canal -
8– miles long - world’s longest irrigation canal - 800 miles
- salinity - increase 3x
-surface area - decreased 54% - volume - decreased by 15%
- 14.000 square miles of human-made salt
desert - flash extinctions and loss of fishing
industry
> 60,000 people unemployed - wetland destruction and wildlife - loss of
50% of all bird and animal species - “salt rain”
> wind blown salt -> kills crops
> salt settling on glaciers in the
Himalayas -> accelerating melting - climate changes
> decreased moderating effect of sea ->
hotter summers, colder winters
> less rain
> shorter growing season - increased use of pesticides and fertilizers
by farmers -> groundwater contamination
-> increased infant mortality and cancers - 20-50% decreased crop yeild
28
Q
TRADE OFFS
Withdrawing groundwater
A
- advantages
> useful for drinking and irrigation
> available year-round
> exists almost everywhere
> renewable if not over-pumped or
contaminated
> no evaporation losses
> cheaper to extract than most surface
waters
- disadvantages
> aquifer depletion from over-pumping
> sinking of land (subsidence) for
over-pumping
> aquifers polluted for decades or
centuries
> saltwater intrusion into drinking water
supplies near coastal areas
> reduced water flows into surface waters
> increased cost and contamination from
deeper wells
29
Q
Case Study: Ogallala Aquifer
A
- world’s largest known aquifer
- mid-western U.S. - 8 states (South
Dakota, Nebraska, Kansas, Colorado,
Wyoming Oklahoma, New Mexico, Texas) - fossil aquifer - filled during last ice age
- being pumped 8-10x faster than natural
recharge rate - transformed prairie land (with little rain) ->
productive farmland that produces 20% of
agricultural output ($32 billion/year) - depletion is encouraged by government
subsidies to farmers to grow “thirsty”
crops, and not to improve efficiency of
irrigation
NOTE: of all the water from the Ogallala aquifer was on the surface, it would cover all 50 stats with 1.5 feet of water
30
Q
Case Study: James Bay Watershed Transfer
A
- involved creating 600 dams to alter, and
even reverse, the flow of 19 giant rivers - would flood areas utilized by Cree and
Inuit tribes - phase 2 was postponed due to opposition
and the fact that phase 1 created more
electricity than could be sold
31
Q
Benefits of Reducing Water Waste
A
- reducing waste to 15% will allow us to meet most of the world's water demands for the foreseeable future - decrease burden on waste water plants - decreased need for dams and water transfer projects (will disrupt fewer habitats and displace less people) - slow groundwater depletion - save $ - save energy
32
Q
Reducing Irrigation Water Waste
Solutions
A
- line canals bringing water to irrigation
ditches - irrigate at night to reduce evaporation
- monitor soil moisture to add water only
when necessary - grow several crops on each plot of land
(poly-culture) - encourage organic farming
- avoid growing water-thirsty crops in dry
places - irrigate with treated urban waste water
- import water-intensive crops and meat
33
Q
Reducing Water Waste
Solutions
A
- redesign manufacturing processes to use less water - recycle water in industry - landscape yards with plants that require little water - use drip irrigation - fix water leaks - use water meters - raise water prices - use water-less composting toilets - require water conservation in water-short cities - use water-saving toilets, shower-heads, and front-loading clothes washers - collect and reuse household water to irrigate lawns and non-edible plants - purify and reuse water for houses, apartments, and office buildings
34
Q
WHAT CAN YOU DO?
Water Use and Waste
A
- use water-saving toilets and faucet
aerators - shower instead of taking baths, and take
short showers - repair water leaks
- turn off sink faucets while brushing teeth,
shaving, or washing - wash only full loads of clothes or use the
lowest possible water- level setting for
smaller loads - use recycled (gray) water for watering
lawns and household plants and for
washing cars - wash a car from a bucket of soapy water,
and use the hose for rinsing only - if you use a commercial car wash, try to
find one that recycles water - replace your lawn with native plants that
need little if any watering - water lawns and yards in the early
morning or evening - use drip irrigation and mulch for gardens
and flowerbeds
35
Q
Benefits of Flooplains
A
- fertile soil -> productive farmland
- nearby rivers for transportation and
recreation - flatland’s for urbanization and farming
- recharge groundwater
- ample water for irrigation
- highly productive wetlands
