Water resources and conservation

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Water resources and conservation
GEOL 3000 Winter 1999
(Image sources CA DWR)
2
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 can only come from
  greater irrigation.
• New water sources will need to be found to meet
  these twin resource needs.

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Straining the limits.

• The lowest cost and most reliable sources of
  water have already been developed around the
  world.
• New sources will have much higher financial and
  environmental costs than those already built (2-3
  times that of existing systems to build and run).
• The UN Rio Conference called for more
  comprehensive management and more efficient water
  use rather than simply throwing money at new
  projects.

4
Water use patterns

• Irrigated agriculture produces around 40 of the
  worlds food and uses about 70 of water
  supplies.
• 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.
• Many countries and regions are becoming
  water-stressed as surface waters are
  over-exploited and groundwater is mined.

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Solutions to the problem

• Technical - e.g. more intensive agriculture,
  recycling wastewater, desalinization of sea
  water, major interbasin transfers
• Economic - e.g. transferring water to the highest
  and most beneficial uses, a free market for
  water.
• Political - e.g. new laws and codes to enforce
  efficient use and conservation.
• Social - e.g. population control to keep down
  urban populations and reduce demands for
  additional food production

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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 allowed California to
  become the most populous state in the nation and
  the worlds seventh 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

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Rising pressures

• CA water demand has risen fast due to economic
  development and population growth.
• Water projects must allow for increased demands
  for environmental protection.
• The design drought of 1928-34 has turned out to
  be less severe than more recent climatic
  variations (e.g. 1987-92).

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But dont we use water efficiently?

• Look around you.clearly the answer is no. But
  why?
• Water development and delivery costs have been
  heavily subsidized as a tool to develop new
  areas.
• We did not internalize the environmental costs of
  water development into the past price structure
• We have not included an adequate cost element in
  the price of water to pay for future water
  development and management costs.
• Water has been perceived as cheap and unlimited.