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10/13/2011
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ES 10 October 6th and 11th
• Distribution of water on earth, amount of fresh water available?
• U.S. water use, how much, what for
• Unequal Distribution: floods and scarcity
• Reasons for fresh water shortages?
• Some technological solutions to water shortages (Pros and Cons): groundwater, dams, watershed transfer, desalination, IPR and improving efficiency
• Review unique properties of water.
• Water Pollution: general definition, analysis, source, major types of water pollution
Supply of Water Resources &
The Hydrologic Cycle (good news)
annual transfer rates in thousands of cubic kilometers (103 km3)
The Salt Water Planet
• Oceans: 71% of Earths surface
• ~97.4% salt water
– Unusable for drinking, irrigation and most industry
• ~2.6% fresh water
– Ice
– groundwater
– surface waterGroundwater accounts for ~ 35 – 55 times as much water
as in all lakes, rivers, atmosphere and soil
Freshwater Readily accessible freshwater?
Biota0.0001%
Rivers0.0001%
Atmosphericwater vapor
0.001%
Lakes0.007%
Soilmoisture0.005%
Groundwater0.592%
Ice capsand glaciers
1.984%
0.014%
5,500
5,000
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
1900 1920 1940 1960 1980 2000
Wa
ter
us
e (
cu
bic
kil
om
ete
rs p
er
yea
r)
Total use
Agricultural use
Industrial use
Domestic use
Year
Global Water Use 1900 ‐ 2000 Use of Water Resources in US
United States
Industry 11%
Domestic 10%
Powercooling
38%
Agriculture41%
Fig. 13.5, p. 298
US: highest per capita water use in the world: ~1280 - 1370 gallons per person/day…OR
500,000gal/person/year
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1 automobile
1 kilogramcotton
1 kilogramaluminum
1 kilogramgrain-fed beef
1 kilogramrice
1 kilogramcorn
1 kilogrampaper
1 kilogramsteel
400,000 liters(106,000 gallons)
10,500 liters(2,400 gallons)
9,000 liters(2,800 gallons)
7,000 liters(1,900 gallons)
5,000 liters(1,300 gallons)
1,500 liters(400 gallons)
880 liters(230 gallons)
220 liters(60 gallons)
1Kg ~ 2.2Lbs
Problem: Unequal Distribution of WaterStorms & Floods: too much water
• Floods are a natural phenomena, needed to renew and replenish nutrients and groundwater
• Aggravated by human activities; removing vegetation for urban development, improper logging, overgrazing of domesticated animals, forest fires, mining, destruction of marsh land……
• ~39% of deaths caused by natural disasters are caused by floods
In St. Louis, the Mississippi remained above flood stage
for 144 days between April 1 and September 30, 1993.
Too Much Water / StormsHurricanes, cyclones and storms bring waves and coastal flooding
STORM SURGES
Hurricane Andrew • ~~158 million
158 million living in an are the size of Wisconsin.80% consists of floodplains.Clearing of coastal MangroveForests aggravates problems.
Bangladesh, April 1991
Hurricane Katrina8/29/05
Too Much Water / Fluvial Systems
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Pajaro River flood, 1995
Soquel Ave Bridge, Santa Cruz, 1982(looking toward Front Street)
Villahermosa City, Capital of Tabasco State Mexico Nov 2nd 2007, >800,000 homeless and ~ 80% is underwater
June, 2008
Pakistan Floods, July 2010~2,000 fatalities, >1,000,000 homeless
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Floodplain Management Plan?
• Do research and develop frequency curve
• Prohibit certain types of buildings / activities in high
risk zones
• Construct floodways that will allow water to flow through community with minimal damage
• Channelization: deepen, widen to allow > runoff
• Elevate or “flood‐proof” buildings
• Build artificial levees / embankments, flood control dams
• There is no 1 solution…. Consider relocating? Move?
Too little waterWhat causes fresh water shortages?
•Water Stress: low per capita availability of water caused by increasing numbers of people relying on limited runoff.
•Dry Climate
•Drought: A prolonged period where a region receives below average precipitation. A normal, recurring feature of most climates.
•Read this article: “Many States Seen Facing Water Shortages”http://www.huffingtonpost.com/huff-wires/20071026/vanishing-water/
How can we increase freshwater supplies for a growing human population?
6 technological solutions to “water scarcity” or shortages A
general term describing insufficient water to satisfy normal requirements, a
relationship between demand for water and it’s availability.
1. Extract Groundwater
2. Build Dams and Reservoirs to store runoff
3. Bring in surface water from other areas: Watershed Transfer
4. Desalination
5. IPR (Indirect Potable Reuse)
6. Improve Efficiency of Water Use
Zone of aeration, saturation , water table Ground WaterAquifers and Aquicludes
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Porosity and Permeability
Zone of Recharge, Zone of Discharge, Flow Rates and Artesian Conditions
How fast does groundwater move?Q=KIA, or Q=K*Head*Area, or Q=K*Rise/Run* Area
K=permeability coefficient or “hydraulic conductivity" , Zone of Discharge, Flow Rates and Artesian Conditions
Evaporation and transpiration
Evaporation
Stream
Infiltration
Water tableInfiltration
Unconfined aquifer
Confined aquifer
Lake
Well requiring a pump
Flowingartesian well
Runoff
Precipitation
ConfinedRecharge Area
Aquifer
Less permeable materialsuch as clay Confining permeable rock layer
Zone of Recharge, Zone of Discharge, Flow Rates and Artesian Conditions
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Cone of Depression
Cone of Depression
Initial water table
Cone ofdepression
Originalwater table
Loweredwater table
Named in 1898 after it’s
“type locality” in Ogallala Nebraska.
Deposition of material occurred
between ~30 – 2 million yrs BP.
Consists of coarse and fine grain
sedimentary rock and sediments.
Most of the water came from melting of the last glacial maximum,5,000 – 10,000 yrs ago.
Between 1980 to present, the rate of drop has decreased in many areas due better irrigationpractices, wind breaks, croprotation, terracing, but it is still dropping in most places.
Some areas have been rising.The Ogallala Aquifer
Ogallala Aquifer~450,000km2
holds ~3,608 Km3 (USGS ‘05)
In some places, water is pumped
out 8 – 10 times faster than
recharge rate.
~30% of all ground water
used for irrigation in US.
Provides drinking water for ~82% of
people living within the area
In 2000, irrigation withdrawals
were ~17 billion gal/day!
WYOMING
SOUTH DAKOTA
NEBRASKA
COLORADOKANSAS
OKLAHOMA
NEW MEXICO
TEXAS0 100
Kilometers
Less than 61 meters (200 ft)
61-183 meters (200-600 ft)
More than 183 meters (600 ft)(as much as 370 meters or 1,200 ft.in places)
0 160
Advantages / Disadvantages of Extracting Groundwater
• Year round use
• No evaporation, responds less to dry seasons
• Often less expensive to develop than surface water systems
• Potential problems caused by overuse
– Water table lowering, “overdraft”, increases cost to mine aquifers (provides drinking water for over 2 billion people,
>1 billion people in Asia)
– Crustal or “Fluid Loss” subsidence
– Chemical contamination of groundwater
– Reduced stream flow
– Salt water intrusion
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GroundwaterOverdrafts:
High
Moderate
Minor or none
Subsidence:
High
Moderate
Minor or none
9 meters of subsidence in ~52 years, 1925 – 1975
Since late 1970’s subsidence decreased to <1m due to reduced groundwater pumping
Long Beach CAwithdraw of petroleum resulted in up to 9 meters of ground subsidence
Salt Water Intrusion
• Often problematic in coastal aquifers
– Rate of pumping > rate of recharge
– Inland water table drops
– Seawater begins to fill in voids
– Solutions?: dig deeper wells, move well locations, watershed transfer or find other source, use less water?
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How can we increase freshwater supplies for a growing human population?
5 Technological Solutions to Water Scarcity:
1. Extract Groundwater
2. Build Dams and Reservoirs to store runoff
Why Build a Dam?PROS:
• Hydroelectric Power / Provide Electricity / Improve Economy decrease dependence on coal / nuclear
• Provide New Fishing Industry / Improve Economy
• Provide Water for Human Consumption
• Flood Control / Reduce Downstream Flooding
• Provide Water for Irrigation / Increased Food Production
• Provide Recreation / Swimming, Boating, Fishing
China’s “3 Gorges Dam” Pros
• Reduced the dependence on Coal
• Generates ~10% of China’s electricity, = to ~10 Hoover Dams, or enough to power a city 10X as large as LA!
• Help reduce CO2 emissions, fewer coal burning plants
• Reduce flooding; over 500,000 have been killed by floods on the Yangtze River in last 100 years, 4,000 in 1998
• The cost of damage from the 1998 flood equals the cost of the dam
• Increases irrigation for cropland below dam
• Increases rivers shipping capacity
Why Build a Dam?CONS:
• Dams are expensive to build, danger of collapse, seismic safety now a concern, since many built long ago
• Loss of water through evaporation
• Loss of biodiversity; sardines, mackerel, shrimp, lobster industry loss in Egypt, 17 of 47 fish species left in Nile, loss of ~30,000 jobs
• Genetic Pollution; less sediment downstream, water > clear, trout and eagles appear in Colorado River
• Deltas receive less sediment and coastal erosion occurs, i.e. Nile and Mississippi River Delta
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St. Francis Dam1926 ‐ 1928
59 meters (195ft) tall
108 meters (608ft) long
China’s “3 Gorges Dam” Cons
• Cost is at least 26 billion
• Displaced over 1.24 million people, 1,350 villages and cities, many with archeological sites
• Floods large areas of croplands and forests
• Created a 600 km long reservoir that will collect waste, untreated sewage, sediment and cause crustal subsidence
• The large reservoir is eroding shorelines, causing slope instability / landslides along edge of reservoir
China’s “3 Gorges Dam” Cons
• It’s built on a seismically active area, ~80 small cracks already discovered, risk of dam breaking?
• Disrupts spawning and migration of some fish downstream
• Could end up releasing more methane than the CO2 from coal burning plants not needed
• Farming regions below dam will not receive nutrient rich sediments from floods
• Lack of sediment in delta cause saltwater to move inland
Sierra de la Laguna, near the town of Miraflores
Other dams completely filled with sediment in Ca: San Clemente Dam on Carmel RiverGibraltar Dam on Santa Ynez RiverMatilija Dam on the Ventura RiverRindge Dam on Malibu Creek
Aswan Dam was completed in 1970. Located ~600 miles north of Cairo.
Dam enables year round irrigation which also contributes to a regional rise in water table.
Fertilizers, pesticides, soil additives needed. Costs: ~100 million/yr, uses up much of the hydroelectric energy created from the dam.
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Mississippi River discharges~3.7 million gal/sec into the Gulf of Mexico
The sediment supply hasDecreased ~50% in Last 100 years
Mississippi River Delta~40% of all coastal wetlands in US, ~35 Sq miles lost per year on Avg
The height of a storm surge is reduced by ~1 foot for every 3 Sq miles (3 mi2 = 1,920 acres) of marsh that it crosses.
Over 1.2 million acres or 1,875 mi2 have already been lost
Dams & the Mississippi River Delta
• Dams and artificial levees ultimately lead to erosion.
• Further loss of delta and salt marsh comes from “diking, draining and filling” for agriculture, industry and residential
• compaction, subsidence, SL rise & wave erosion VS deposition or “sedimentation”
Currently: ~11‐13mm/yr……. VS ~5.9‐7.5 mm/yr……
• Solutions: “Move the Mississippi”http://www.usatoday.com/news/nation/2005‐11‐21‐wetlands‐restoration_x.htm Web Link (for over 3 billion $$) (geologist Sherwood Gagliano)
• Rechannel / redirect sediment to starved areas, Stop draining / filling, establish zoning of coastal areas, Build dams / retaining walls to prevent saltwater flooding of freshwater marshes 11-13mm/yr VS 5.9 – 7.5mm/yr
compaction, subsidence, SL rise & wave erosioVS deposition or “sedimentation”
year 1900 1950 1980 1998
# of dams >15m high
worldwide
0 5270 36,562 47,655
(China 22,000)
Dams and Development
• Developed countries
– some new dams planned; many dams being decommissioned; in US decommissioning>construction
• Developing countries
– Many new large dams under construction for irrigation, flood control, hydropower, water supply
– India, China, Turkey, Iran and Indonesia, Japan are currently most active dam building countries
Klamath River Dams• Four dams on the Klamath River (J.P.Boyle, Copco 1, Copco 2 and Iron Gate) are all coming down…….. Starting in 2020. “World’s biggest dam removal project…”
• These dams supply enough electricity for 70,000 homes
• Future challenge is to make sure salmon restoration will not be compromised by farming
• To Help Salmon, 4 Klamath Dams Coming Downhttp://www.seattlepi.com/national/article/To‐help‐salmon‐4‐Klamath‐dams‐
coming‐down‐883692.php Web Link
• Tearing Down The Elwah River Damhttp://www.popularmechanics.com/science/environment/water/2294301 Web Link
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Dams in California, some #’s about SANDRead this after class
• 16,000 mi2 of states coastal watersheds are effected by dams.
• Flow of sand to beaches has been reduced by ~25% or
3.6 million Yds3/yr or 360,000 dump trucks/yr
• Total sand trapped behind Ca’s coastal dams is ~ 200 million Yds3, which = to a line of dump trucks bumper to bumper around the word 4 times. Varies with location: ~5% in northern Ca, 31% in central Ca and 50% in southern Ca.
• Effects of beach widths??? Not that much in So Ca. Coastal engineering structures (dredging new marinas, construction on dunes) has led to 170 million cubic yards of new sand between 1930 ‐ 1993 (2.7 million Yds3/yr) between Santa Monica and San Diego.
• Engineering + wave climate (El Nino / La Nina) partially overshadows reduction of sand from dam construction.
source: Gary Griggs
How can we increase freshwater supplies for a growing human population?
5 Technological Solutions to Water Scarcity:
1. Extract Groundwater
2. Build Dams and Reservoirs to store runoff
3. Bring in surface water from other areas: Watershed Transfer
Long history: Asia, Middle East, Roman Empire (38mill gal/day),
CA, politics, power, greed, pop growth, ecosystem disruption
PROS: development, can help control flooding, provide water for
industry, agriculture, domestic use,
Pont Du Gard Aqueduct, Franceconstructed by Roman Empire, ~2,000 years old,~51 kilometers long, bridge carried 44 mill/gal/day
• LA Aqueduct: designed by William Mulholland & begins in 1909,
cost 24 million, opens November 13th, 1913, pop of LA doubles in 10 yrs, provides 200mill gal/day to LA. Stress in Owens Valley. (Collapse of St Francis Dam (1926 – 1928 / Mulholland project)
20 bill gal water, 100 ft high, ~500 killed)
• California Aqueduct: completed in 1941, longest in world at
~440 miles, brings 500 mill gal/day to LA region. Population of LA county ~10 million, without aqueducts, LA has enough water to support ~250,000. Water pump over Tehachapi Mnts (up 600m) is largest in world: >2mill gal/water/minute!
• Hetch Hetchy Aqueduct: completed in 1934, took 20 years to
build, 176 miles of dams, reservoirs, tunnels, pump stations provides ~240 mill gal/day to SF Bay region
• New York City: three aqueducts bring 1.3 billion gal/day from Catskills, one completed in 1967, the other two in 1936 and 1917, much repair work needed.
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California Water Project Transferring water from one place to another
LA relies on aqueducts for ~85% of its water. Water flows by pumps and gravity to heavily populated areas and arid agricultural regions in southern California.
Some Cons:~20% of the En in Ca is used for pumping water, CO2 output
Reduces flushing capacity, lowers groundwater table, lowers lake levels, threatens aquatic organisms
Colorado River Basin: 14 major dams, 100’s of smaller ones. ~20,000 dump trucks of sediment deposited every day in Lake Mead and Powell.
The Aral Sea Disaster
The Aral Sea (ecological, economical and health) Disaster
• The Aral Sea was once the world’s 4th largest fresh water lake.
• World’s largest irrigation canal (~1,300Km) transfers water out
• Since 1961 the salinity has tripled, 58% less surface area, water level dropped 72 feet, ~83% of water is lost, >14,000 sq mi!!
• ~85% of regions wetlands lost, and ~1/2 bird and mammal species disappeared, >80% of native fish species.
• Exposed salt and dust blows over 300Km: pollutes water, kills wildlife, harms crops, causes health problems.
• Dust is accumulating on Himalayan glaciers possibly causing them to melt faster than normal.
• Farmers have increased insecticides and fertilizers: chemicals are leaching into the groundwater, the source of drinking water for many of the regions 45 ‐ 58 million that live within the areas watershed.
• Greatly increased health problems from a combination of toxic dust, salt and contaminated water for a growing number of the 58 million people living in the Aral Sea's watershed.
Such problems include abnormally high rates of:
• infant mortality, tuberculosis
• Anemia, respiratory illness (one of the world's highest)
• eye diseases (from salt dust), throat cancer
• kidney and liver diseases (especially cancers)
• arthritic diseases, typhoid fever, hepatitis
The Aral Sea (ecological, economical and health) Disaster
