Chapter 20 Water Supply, Use and Management

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Chapter 20 Water Supply, Use and Management
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Water

• Water makes life on Earth possible- universal
  solvent, store heat, high surface tension,
  penetrated by sunlight, lighter as a solid
  compared to a liquid
• 97 of total in oceans others glaciers, ground
  water, lakes, atmosphere, rivers
• 99 unavailable or unsuitable
• Residence time varies from 1,000s to 9 days.
• Water is cheap and once plentiful but now

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Groundwater and Surface Flow

• Vocabulary- ground water, water table, recharge
  zone, discharge zones, effluent and influent
  streams, vadose zone, aquifer, cone of depression

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U.S. Water Supply

• What is a water budget?
• Shows inputs, outputs, and storage
• Precipitation evaporation runoff
• 10 precipitation
• 66 precipitation that evaporates or transpires
• 34 surface or groundwater storage
• 50 of the 34 is available 95 of the time-
  reasons?

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Reasons

• Runoff patterns (arid areas low precipitation and
  runoff, high evaporation)
• Droughts
• Groundwater use and problems
• 50 of U.S. population uses ground water for
  drinking water
• Overdrafting uses more than naturally replaced
  (dryland agriculture)
• Desalinization- expensive -10x more than
  traditional water supplies, tied to energy
  sources, environmental damage

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Water Use

• Off-stream (humans, industry) vs. in-stream
  (hydroelectric, habitats) uses
• Transportation (past to present)
• Romans
• aqueducts
• New York for over 100 years
• groundwater pollution, runoff, population

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Water Conservation

• Agriculture (drip irrigation, mulching, GMCs)
• Domestic (use native plants, gray water, fix
  leaks)
• Industry (use cooling towers, develop water
  recycling technologies)
• Perception (desert vs. oasis mentality)
• Sustainability use of water allows society to
  develop and flourish without degrading hydrologic
  cycles or environment

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Water Management

• What is a variable water source approach?
• Planning for natural excesses and deficiencies
• import water
• develop new sources
• use reclaimed water
• conservation plan

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Subjects of Concern Government, Public, and
Agricultural groups

• Wetlands- wet at least part of year, particular
  vegetation and soil
• Functions
• Release water slowly
• Groundwater recharge
• Nursery grounds
• Natural filters
• Inland buffer
• Carbon storage

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Wetland restoration

• 50 of U.S. wetlands have disappeared- drained,
  diked, filled for mineral exploration,
  agriculture, development
• Restoration is not always successful
• complex relationship between hydrology,
  sediments, and plants
• Restoration is done through mitigation as
  mandated in NEPA of 1969
• destroy a wetland must create a wetland

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Dams

• Loss of land, cultural and biological resources
• Storage of sediment behind the dam
• Changes in downstream hydrology and sediment
  transport
• Expensive, constructed with federal taxes
• Conflicts over use- aesthetic vs. industrial
• Federal dollar provide subsidized water for
  agriculture and ranching

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• Example- Edwards Dam, Maine
• Constructed- 1837 for flood control
• Opposition at that time- salmon spawning grounds
  damage
• Fish bridge installed but damaged 1938
• 1842-1847 provided power to sawmill
• Flooded in 1839, 1846, 1855, 1870
• 1882- mill power supply
• 1913- electric power generator
• 1974- damaged and repaired
• 1980- textile mill closes
• 1991- permit for increased electric power
  generation
• 1995- owners withdrew proposal
• 1995- Environmental Impact Statement- dam
  removed
• Present- migrating fish are back, drift fishing
  (sport fishing added 48 million to state),
  improved water quality, spawned interest in
  upstream dam removal

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Stream Channelization

• What is it?
• Straitening, widening, clearing, lining existing
  stream
• What it does?
• Destroy natural hydrologic qualities
• Loss wetlands
• Aesthetic degradation
• Increased flooding downstream

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Stream Morphology
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Flooding

• Most experienced natural hazard in the world
• Benefits of floodplains
• Stores water and nutrients
• Forms nutrient-rich soils
• Floodplain wetlands
• Environmental diversity

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Water management of the Colorado River Basin