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Water Use and Management . CHAPTER 17. What two factors are the most important in determining the availability of water in Northville?. Chapter Overview Questions. Why is water so important, how much freshwater is available to us, and how much of it are we using?

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chapter overview questions
Chapter Overview Questions
  • Why is water so important, how much freshwater is available to us, and how much of it are we using?
  • What causes freshwater shortages, and what can be done about this problem?
  • What are the advantages and disadvantages of withdrawing groundwater?
  • What are the advantages and disadvantages of using dams and reservoirs to supply more water?
chapter overview questions1
Chapter Overview Questions
  • What are the advantages and disadvantages of transferring large amounts of water from one place to another?
  • Can removing salt from seawater solve our water supply problems?
  • How can we waste less water?
  • How can we use the earth’s water more sustainably?
  • What causes flooding, and what can we do about it?
when did the cuyahoga river catch fire
When did the Cuyahoga river catch fire?
  • 1868, 1883, 1887, 1912, 1922, 1936, 1941, 1948, 1952, and 1969.
editorial lake erie dead again
Editorial: Lake Erie dead again?
  • Tributaries of Lake Erie aren't catching fire as they did a half-century ago. But by several important measures, the lake -- generally considered the bellwether for the health of the other four Great Lakes -- has declined to a point as bad as or worse than it has ever been. Detroit Free Press 10-16-2011
  • By several important measures, Lake Erie, generally considered the bellwether for the health of the other Great Lakes, is at a point as bad as or worse than it's ever been.
water facts
WATER FACTS
  • We currently use more than half of the world’s reliable runoff of surface water and could be using 70-90% by 2025.
  • About 70% of the water we withdraw from rivers, lakes, and aquifers is not returned to these sources.
  • Irrigation is the biggest user of water (70%), followed by industries (20%) and cities and residences (10%).
water facts1
WATER FACTS
  • About 41% of the world’s population lives in river basins that do not have enough freshwater.
  • Many parts of the world are experiencing:
      • Rivers running dry.
      • Lakes and seas shrinking.
      • Falling water tables from over pumped aquifers.
hydrosphere
Hydrosphere:
  • All the H2O at or near the surface of the earth
  • Amount of H2O essentially constant and moves between different reservoirs
  • 100 million billion gallons move through hydrologic cycle annually
water resources
Water Resources
  • Hydrologic Cycle
  • Describes the circulation of water as it:
    • Evaporates from land, water, and organisms (transpires from plants)
    • Enters the atmosphere
    • Condenses and precipitates back to the Earth’s surfaces
    • Moves underground by infiltration or overland by runoff into rivers, lakes and seas
hydrologic cycle2
Hydrologic Cycle
  • Solar energy drives the hydrologic cycle by evaporating surface water.
    • Evaporation - changing liquid to a vapor below its boiling point
    • Sublimation - changing water between solid and gaseous states without ever becoming liquid
      • Freezer burn
hydrologic cycle3
Hydrologic Cycle
  • Humidity - amount of water vapor in the air
    • Saturation point - when a volume of air contains as much water vapor as it can hold at a given temperature
    • Relative humidity - amount of water vapor in the air expressed as a percentage of the maximum amount that can be held at that temperature
hydrologic cycle4
Hydrologic Cycle
  • Dew point - temperature at which condensation occurs for a given amount of water vapor
    • Condensation nuclei - tiny particles that facilitate condensation
      • Smoke, dust, sea salt, spores
    • A cloud is an accumulation of condensed water vapor in droplets or ice crystals. When droplets become large enough, gravity overcomes air currents and precipitation occurs.
regions of plenty and regions of deficit
Regions of Plenty and Regions of Deficit
  • Three principal factors control global water deficits and surpluses:
    • Global atmospheric circulation
    • Proximity to water sources - lake effect snow
    • Topography
regions of plenty and regions of deficit1
Regions of Plenty and Regions of Deficit
  • Mountains act as cloud formers and rain catchers.
    • Air moves up the windward side of a mountain, pressure decreases, air cools.
    • Eventually saturation point is reached, and moisture in the air condenses.
    • Rain falls on the mountaintop.
        • Cool, dry air descends and warms, absorbing moisture from other sources (Rain shadow).
major water compartments
Major Water Compartments
  • Oceans
    • Together, oceans contain more than 97% of all liquid water in the world.
    • Contain 90% of world’s living biomass
    • Moderate earth’s temperature
    • Average residence time of water in the ocean is about 3,000 years
major water compartments1
Major Water Compartments
  • 2. Glaciers, Ice, and Snow
    • 2.4% of world’s water is freshwater.
    • 90% in glaciers, ice caps, and snowfields
        • As recently as 18,000 years ago, one-third of continental landmass was covered by glacial ice sheets.
        • Now, Antarctic glaciers contain nearly 85% of all ice in the world.
        • Greenland, together with ice floating around the North Pole, is another 10%.
major water compartments2
Major Water Compartments
  • 3. Groundwater
    • Second largest reservoir of fresh water 22%
      • Infiltration - process of water percolating through the soil and into fractures and permeable rocks
      • Zone of aeration - upper soil layers that hold both air and water
      • Zone of saturation - lower soil layers where all spaces are filled with water
      • Water table - top of zone of saturation
groundwater
Groundwater
  • Aquifers - porous layers of sand, gravel, or rock lying below the water table
    • A good aquifer needs to be both porous and permeable
    • Artesian - Pressurized aquifer intersects the surface (water flows without pumping).
  • Recharge zones - area where water infiltrates into an aquifer
      • Recharge rate is often very slow.
      • In many areas groundwater is being removed faster than it can be replenished
groundwater recharge
Groundwater: Recharge
  • Effective recharge depends on how porous and permeable soil is
    • Porosity: Proportion of open space between soil particles higher porosity in well rounded, coarse grained rocks
    • Gravel : 25-45%, Clay: 45-55%, Sandstone: 5-30%
  • Permeability: how readily fluid passes through a material
    • Depends on the pore size and how well they are interconnected
    • Clay has high porosity but low permeabilty
slide33

Less porosity

More porosity

groundwater1
Groundwater
  • Water table follows the topography but more gently
  • Intersection of water table and ground surface produces lakes, streams, spring (Iargo), wetlands…
  • Ground water flows from higher elevation to lower, from areas of lower use to higher use, from wet areas to dry areas.
groundwater aquifers
Groundwater: Aquifers
  • Unconfined Aquifer: open to atmosphere e.g., overlain by permeable rocks and soils
  • Confined aquifer: sandwiched between aquicludes
    • Artesian System: Water rises above the level in aquifer because of hydrostatic pressure
major water compartments3
Major Water Compartments
  • 4. Rivers and Streams
    • Precipitation that does not evaporate or infiltrate the ground runs off the surface, back toward the sea.
    • Best measure of water volume carried by a river is discharge
        • The amount of water that passes a fixed point in a given amount of time
          • Usually expressed as cubic feet per second
major water compartments4
Major Water Compartments
  • 5. Lakes and Ponds
    • Ponds are generally considered small bodies of water shallow enough for rooted plants to grow over most of the bottom.
    • Lakes are inland depressions that hold standing fresh water year-round.
      • Unless emptied by an outlet stream both ponds and lakes will eventually fill with sediment.
major water compartments5
Major Water Compartments
  • 6. Wetlands
    • Play a vital role in hydrologic cycle
    • Lush plant growth stabilizes soil and slows surface runoff, allowing more aquifer infiltration.
      • Disturbance reduces natural water-absorbing capacity, resulting in floods and erosion in wet periods, and less water flow the rest of the year.
        • Half of U.S. wetlands are gone.
major water compartments6
Major Water Compartments
  • 7. The Atmosphere
    • Among the smallest water reservoirs
      • Contains < 0.001% of total water supply
      • Has most rapid turnover rate
      • Provides mechanism for distributing fresh water over landmasses and replenishing terrestrial reservoirs
slide40

What happens when we take water out of the ground?

Lower water table – create cone of depression around a well

Lower the regional water table by overlapping cones of depression

what happens when we take water out of the ground
What happens when we take water out of the ground?
  • Compaction and subsidence
    • Soils compress & settle causing depressions
    • Building damage, collapse
    • Flooding and coastal erosion
      • Venice, Galveston/Houston (80 sq km permanently flooded), San Joaquin Valley (9m subsidence)
    • Pumping in water is no solution
slide42

What happens when we take water out of the ground?

Land subsidence in San Joaquin Valley , California

depleting groundwater
Depleting Groundwater
  • Groundwater is the source of nearly 40% of fresh water in the U.S.
  • Heavy pumping can deplete an aquifer.
  • Ogallala Aquifer
    • Underlies 8 states between Texas and North Dakota
    • Wells have dried up, entire towns are being abandoned
    • Will take thousands of years to refill
there will be water ogallala future issues
There Will be Water: Ogallala future issues
  • Keystone XL pipeline over runs part of the aquifer. Canada to IL, OK, TX
  • T. Boone Pickens buys 68,000 acres in TX with H2O rights
  • Warren Buffet invests in Nalco/Ecolab and purchasing land over aquifers
  • Water = the new oil
  • Water for profit? Unconscionable?
slide46

The Gulf Coastal Plain Aquifer System

  • Underlie 290,000 sq. mi. from Texas to Florida, including offshore areas to the edge of the Continental Shelf.
  • Water withdrawals from the aquifer system have caused
    • lowering of water table
    • reduced discharges to wetlands
    • induced movement of saltwater into parts of aquifers that previously contained freshwater;
    • subsidence
depleting groundwater1
Depleting Groundwater
  • Withdrawing large amounts of groundwater in a small area causes porous formations to collapse, resulting in subsidence (settling).
    • Sinkholes form when an underground channel or cavern collapses. Results in permanent loss of aquifer.
    • Saltwater intrusion can occur along coastlines where overuse of freshwater reservoirs draws the water table low enough to allow saltwater to intrude.
other effects of groundwater overpumping
Other Effects of Groundwater Overpumping
  • Sinkholes form when the roof of an underground cavern collapses after being drained of groundwater.
slide50

Trade-Offs

Withdrawing Groundwater

Advantages

Disadvantages

Useful for drinking and irrigation

Aquifer depletion from overpumping

Sinking of land (subsidence) from overpumping

Available year-round

Exists almost everywhere

Polluted aquifers for decades or centuries

Renewable if not overpumped or contaminated

Saltwater intrusion into drinking water supplies near coastal areas

Reduced water flows into surface waters

No evaporation losses

Increased cost and contamination from deeper wells

Cheaper to extract than most surface waters

Fig. 14-7, p. 313

water availability and use
Water Availability and Use
  • Renewable Water Supplies
    • Made up of surface runoff plus infiltration into accessible freshwater aquifers
    • About two-thirds of water carried in rivers and streams annually occurs in seasonal floods too large or violent to be stored effectively for human use.
water availability and use drought cycles
Water Availability and Use: Drought Cycles
  • Every continent has regions of scarce rainfall due to topographic effects or wind currents.
  • Water shortages have most severe effect in semiarid zones where moisture availability is the critical factor in plant and animal distributions.
  • U.S. seems to have 30 year drought cycle.
        • Dust Bowl in 1930s
water availability and use drought cycles1
Water Availability and Use: Drought Cycles
  • Much of Western U.S. is still plagued by drought and overexploitation of limited supply of water.
  • El Nino plays an important role in determining when North America has drought.
  • Global warming may make droughts more frequent and severe.
water availability and use water consumption
Water Availability and Use: Water Consumption
  • Withdrawal - total amount of water taken from a source
  • Consumption - fraction of withdrawn water made unavailable for other purposes (not returned to its source)
    • Degradation - Change in water quality due to contamination making it unsuitable for desired use. Much water that is not consumed is nevertheless polluted.
water availability and use water use is increasing
Water Availability and Use: Water Use is Increasing
  • Many societies have always treated water as an inexhaustible resource.
    • Natural cleansing and renewing functions of hydrologic cycle do not work properly if systems are overloaded or damaged
    • Renewal of water takes time
    • Rate at which we are now using water makes conservation necessary
water availability and use quantities of water used
Water Availability and Use: Quantities of Water Used
  • Human water use has been increasing about twice as fast as population growth over the past century, but impact varies with location.
  • Canada withdraws less than 1% of its renewable supply per year.
  • In Israel, groundwater and surface water withdrawals equal more than 100% of the renewable supply. Obviously, this is not sustainable.
  • U.S. uses 20% of renewable water/yr.
water availability and use agricultural water use
Water Availability and Use: Agricultural Water Use
  • Water use is divided into agriculture, domestic use and industrial use.
  • Worldwide, agriculture claims about two-thirds of total water withdrawal and 85% of consumption.
    • Aral Sea, once the fourth largest inland body of water in world, has been drained.
    • Lake Chad in northern Africa went from 400,000 sq. km to less than 1,000 sq. km.
case study the aral sea disaster
Case Study: The Aral Sea Disaster
  • Once the world’s fourth largest freshwater lake.
  • Water diverted from the Aral Sea and two feeder rivers for irrigation has created a major disaster.
  • 85% of the wetlands eliminated
  • 50% of bird and mammal species have disappeared.
  • Since 1961, the sea’s salinity has tripled and the water has dropped by 22 meters, causing all of the 24 native fish species to go extinct.

Kazakhstan Uzbekistan

water availability and use agricultural water use1
Water Availability and Use: Agricultural Water Use
  • Irrigation can be inefficient.
    • Flood or furrow irrigation
      • Half of water can be lost through evaporation.
      • Flood irrigation used to remove salts from field, but salt contaminates streams
    • Sprinklers have high evaporation.
    • Drip irrigation releases water near roots, conserving water.
water availability and use agricultural water use2
Water Availability and Use: Agricultural Water Use
  • Thus, irrigation is the major consumer of ground water
  • Western states are the major drawers of ground water causing serious environmental problems
slide62

Average annual precipitation (centimeters)

Less than 41

81–122

41–81

More than 122

Most of the precipitation is in the eastern states but…

water availability and use domestic and industrial water use
Water Availability and Use: Domestic and Industrial Water Use
  • Worldwide, domestic water use accounts for about one-fifth of water withdrawals.
    • Only about 10% of consumption
      • But where sewage treatment is unavailable, water is degraded
  • Industry accounts for 20% of global freshwater withdrawals.
    • Can range to 70% in various locations
      • Small proportion is consumed, but degradation is a problem
freshwater shortages
Freshwater Shortages
  • U.N. estimates a billion people lack access to safe drinking water.
    • 2.6 billion lack acceptable sanitation.
  • At least 45 countries, mostly in Africa & Middle East, have serious water stress.
  • Water shortages could lead to wars as population grows and climate change dries up some areas. An underlying cause of the Darfur genocide is water scarcity.
freshwater shortages1
Freshwater Shortages
  • Privatization of public water supply in Bolivia sparked a revolution that overthrew the government in 2000.
  • Multinational corporations are moving to take control of water supplies in many countries.
  • Global warming may make water shortages much worse in many parts of the world.
dams and diversions
Dams and Diversions
  • In 1900 there were 250 dams 50+ ft in the world; today there are more than 45,000.
  • In the U.S. dams are built by Army Corps of Engineers and Bureau of Reclamation
    • Provide cheap hydroelectric power
    • Jobs
    • Reduce flooding
    • Irrigation
    • Recreation
    • Provide year-round water for irrigating cropland
dams and diversions1
Dams and Diversions
  • On the downside, dams
    • Drown free flowing rivers
    • Submerge farmlands and towns
    • Block fish migration e.g. salmon
    • Change aquatic habitats for native species
    • Can sometimes fail, causing catastrophe
      • Johnstown flood (city just east of Pittsburgh, PA) killed 2,200 people when dam broke.
      • Dam failure in China killed 230,000.
song of the morning ranch 2005 2008
Song of the Morning Ranch 2005, 2008
  • 100-year-old dam on their property.
  • Periodically malfunctions and releases high volumes of water into the Pigeon River, significantly harming the environment and the health of the river.
  • Fish kills result from each breach, the most recent incident in June 2008 killing thousands.
song of the morning ranch
Song of the Morning Ranch
  • Ordered to remove dam by court, appealing verdict.
slide76

Provides water for year-round irrigation of cropland

Flooded land destroys forests or cropland and displaces people

Large losses of water through evaporation

Provides water for drinking

Downstream cropland and estuaries are deprived of nutrient-rich silt

Reservoir is useful for recreation and fishing

Risk of failure and devastating downstream flooding

Can produce cheap electricity (hydropower)

Downstream flooding is reduced

Migration and spawning of some fish are disrupted

Fig. 14-13a, p. 317

dams and diversions2
Dams and Diversions
  • Tide of public opinion is turning
  • Army Corps of Engineers announced in 1998 that it would no longer be building large dams and would be removing some older dams to restore natural habitat
  • Sediment carried by rivers eventually fills up dams
  • Lakes behind dams lose huge amounts of water through evaporation and seepage
  • Downriver habitats lose nutrients and the beaches disappear as sediment is no longer available
dams and diversions3
Dams and Diversions
  • Diversion projects can dry up rivers
    • Yellow River in China is dry 226 days per year due to diversions
    • Colorado River in the U.S. is so depleted that most of the year no water reaches the mouth of the river in the Sea of Cortez
    • Mono Lake has been depleted to send water to Los Angeles. Salinity of water doubled, killing the brine shrimp that fed huge flocks of migratory birds
mono lake in california
Mono Lake in California
  • Diversion of water from the lake to Los Angeles has shrunk the lake by 1/3, exposing these towers where calcium- rich springs once entered the lake.
water diversion channelization the kissimmee river project
Water Diversion: Channelization & The Kissimmee River Project
  • To minimize flooding and provide farm land wetlands drained for and river “rechanneled”
    • Dairy Farms and Sugar Plantation moved in
    • Fertilizers and pesticides washed into Florida Bay which caused:
    • Algal Bloom used up dissolved oxygen in water
    • Excessive sedimentation smothered bottom communities and blocked sunlight in deeper water
    • Death of corals, sponges and bottom-communities
    • Loss of habitat of fish and wetland fowl
    • Loss of recharge of groundwater
  • Now the river is being restored to original channel
urbanization and ground water
Urbanization and ground water
  • Loss of Recharge
  • Impermeable cover slows recharge
  • Filling of wetlands kills recharge area
  • Increased flooding
  • Well planned holding pond can help in recharging ground water
increasing water supplies
Increasing Water Supplies
  • Seeding Clouds
    • Condensation nuclei
  • Desalination- removing salt from ocean water or brackish waterto get fresh water
    • Most common methods are distillationand reverse osmosis (uses high pressure to force saltwater through a membrane filter).
      • Three to four times more expensive than most other sources
domestic conservation
Domestic Conservation
  • We could save up to 50% of domestic water usage without change in lifestyle
    • Largest domestic use is toilet flushing
      • Can use low volume toilets or waterless composting
      • Anaerobic digesters use bacteria to produce methane gas from waste
    • Significant amounts of water can be reclaimed and recycled.
        • Purified sewage effluent
          • San Diego pumps water from sewage plant directly into drinking reservoir
domestic conservation1
Domestic Conservation
  • Shift water-hungry crops to regions with more rainfall
  • Use drip irrigation to reduce evaporation loss
  • Use pipes to reduce transport loss
  • Water lawns in morning and evening or opt for no lawn (xeriscape)
  • Direct storm water in recharge basins
price mechanisms and water policy
Price Mechanisms and Water Policy
  • Through most of U.S. history, water policies have generally worked against conservation.
    • In well-watered eastern states, water policy was based on riparian use rights.
    • In drier western regions where water is often a limiting resource, water law is based primarily on prior appropriation rights.
      • Fosters “Use it or Lose it” policies, where if you conserve you lose your rights to the water
price mechanisms and water policy1
Price Mechanisms and Water Policy
  • In most federal reclamation projects, customers were only charged for immediate costs of water delivery.
    • Dam and distribution system costs were subsidized.
    • Underpriced water in some areas amounted to a subsidy of $500,000 per farm per year.
  • Growing recognition that water is a precious and finite resource has changed policies and encouraged conservation across the U.S.
price mechanisms and water policy2
Price Mechanisms and Water Policy
  • Charging a higher proportion of real costs to users of public water projects has helped encourage conservation.
  • Conservation has been successful. U.S. today uses 10% less water than in 1980 but has 37 million more people.
interbasin transfer what s next
Interbasin transfer – what’s next?
  • Transfer water from water-surplus regions to water-deficient regions
  • California : Los Angeles aqueduct moves 150 million gallons/ day from east of Sierra Nevada to LA
  • New York: Water supply to NYC from Finger Lakes region
  • Political problems – Great Lakes