GEOG 3000 Resource Management Freshwater in Danger

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GEOG 3000 Resource ManagementFreshwater in
Danger

• M.D. Lee CSU Hayward Winter 2004

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Water Resources

• Adequate water resources are essential for
  cities, irrigation, industry, recreational use,
  and for our environment.
• Access to water resources is not the same for
  everyone - it doesn't occur universally in the
  quantity and quality that everyone needs.
• The development of new water resource systems is
  increasingly expensive, and access to adequate
  water supplies is already difficult or is
  becoming difficult for some regions, cities and
  social groups.
• The lowest cost and most reliable sources of
  water for large cities have already been
  developed.
• Worldwide, the average cost of most new water
  projects is expected to be two to three times
  that of existing projects.

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Available Resources

• Over 97.5 of all the water on the planet is too
  salty to use/drink (do you know why?)
• About 2 of all the water is locked up in ice
  sheets or glaciers.
• A large proportion of terrestrial water is deep
  underground or has economically challenging water
  quality characteristics e.g. is salty, has high
  levels of arsenic, etc.
• Potentially exploitable surface freshwater
  resources make up a tiny fraction of all the
  water on our planet (perhaps as low as 0.01).

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Water - a changing world

• Urban populations are expanding at a tremendous
  rate, placing growing demands on water sources.
• Massive worldwide population growth requires
  greater food production which must largely come
  from greater irrigation.
• Increased environmental concerns are placing
  greater emphasis on the preservation of healthy
  and natural aquatic ecosystems.
• New water sources will need to be found and/or
  existing sources must be put to better use to
  simultaneously satisfy these multiple resource
  needs.

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The Supply-Side

• Water development to date all over the world has
  traditionally focused on the "supply-side of
  the equation, seeking to satisfy all demands as
  needs.
• The supply side approach places an emphasis on
  engineering solutions to provide water wherever
  and however it is required, usually at the least
  cost and on the notion of full reliability.
• Environmental and other resource costs were not
  usually considered in the equation until the
  1970s.

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The Demand Side Approach

• Increasing costs, mounting environmental damage
  and potential climate modifications and water
  balance changes are placing greater emphasis on
  demand side approaches and acceptable shortages.
• Integrated water resources planning places
  greater emphasis on water use efficiency (aka
  conservation) and beneficial water allocation.
• The UN Rio Conference in 1992 called for more
  comprehensive management and more efficient water
  use rather than simply throwing money at new
  projects.

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Major Water Resource Issues

• Over-extraction of groundwater resources leading
  to saline intrusion and land subsidence.
• Over-exploitation of surface water leading to low
  water flows/levels, wetland destruction, and
  physical impacts from dam and other
  infrastructure construction.
• Lack of water supply and sanitation and
  contaminated water supplies for the poor in
  developing nations.
• Water quality and public health versus allowable
  levels of pollution at what level should we set
  and enforce water quality standards?

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Water use patterns

• Irrigated agriculture produces around 40 of the
  worlds food and uses about 70 of water supplies
  (70 in US too).
• Industry uses about 21 and municipal demand
  takes 6.
• In California, agriculture uses about four times
  as much water as municipal and industrial users
  combined.
• Every Californian, on average uses 120 gallons
  per person per day 2/3 inside and 1/3 outside.
• This is far more than averages for other nations
  and much of this could be conserved with greater
  efficiency of use.

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California - a classic example

• Climatically, a quarter or more of California
  land was desert or at least seasonally dry
  scrubland.
• Redistribution of water has made California the
  most populous US state and the worlds 6th
  largest economy.
• California water systems were built using
  projections of future demand for water and a
  design drought in order to size reservoirs,
  canals, pumping stations and so forth.
• CA water demand has risen fast due to economic
  development and population growth.
• Water projects must, by law, allow increased
  water volumes back into rivers for environmental
  protection.
• The design drought of 1928-34 has turned out to
  be less severe than more recent climatic
  variations (1987-92) and is expected to be
  exceeded by worse droughts to come.
• The effect of global warming is likely to create
  problems.

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Why dont we use water efficiently?

• The supply-side approach has dominated,
  satisfying all of our wants, all of the time,
  with few restrictions.
• Water development and delivery costs have been
  heavily subsidized as a basic public good and as
  a tool to develop new areas.
• We did not internalize the environmental costs of
  water development into the past price structure,
  thus costs have seemed lower than they really
  are.
• Water has thus been perceived as both cheap and
  unlimited so why bother conserving?