Michael Cohen

1
The Delta's Perennial Drought  Instream Flows
for an Over-Allocated River

• Michael Cohen
• Pacific Institute
• February 19, 2005

2
overview

• Drought the Delta
• overview
• Delta restoration
• CO River its delta
• Drought in the basin
• Shortage strategies

3
Delta backwater
4
Cienega
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Delta sykes
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(No Transcript)
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The remnant delta
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Old BOR basin map 1938
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BOR map of CO R basin
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Annual Avg Precip
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Consumptive/Precip map
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Flood Irrigation
13
Powell quote
I wish to make it clear to you, there is not
sufficient water to irrigate all the lands which
could be irrigated, and only a small portion can
be irrigated. I tell you, gentlemen, you are
piling up a heritage of conflict! -- John
Wesley Powell, speech, 1893
14
BOR quote
The basic truth is that the lower Colorado River
is now a stream wholly controlled by man. It was
in its natural state, or nearly so, prior to
closure at Hoover Dam. Try as anyone will, it
cannot be characterized as other than a fully
controlled river. . . . The rivers flow can be
manipulated in the same fashion as the garden
house on the tap outside your home, and is. --
BOR Regional Director West, 1968
15
Historic Delta Flows
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Mead 5-5-00

• Lake Mead
• 5/5/2000

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Mead 4-19-03
Lake Mead 4/19/03
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Lake Mead1142 (7-7-2003)
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CO R Reservoir Elevations 87-04
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Rec model avg hydro
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Prob of shortage no powell protect
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Shortage strategies?

• States Shortage Strategies
• YDP operation
• New storage
• Share shortage with Mexico

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Other Shortage strategies

• Other Shortage Strategies
• Forbearance agreements
• Top-water banking
• Wheeling
• Equitable shortage
• Shortage trust fund

24

• "The West is growing, our water resources are
  going to be called upon to work harder and
  harder, and we all must work together to achieve
  wise management of this most precious resource.
  Water defines the West, and our use of it will
  define the West of the 21st century."
• Water in the West Challenge for the Next
  Century, Report of the Western Water Policy
  Review Commission, June 1998