SWSIReportMay2008

• Title: Colorado Water Supply Conditions Update
• Date: 5/19/2008
• Description: Joint Meeting of the Water Availability & Colorado Flood Task Force Presentation
• Basin: Statewide
• Drought Mitigation - Doc Type: Presentation

ARKANSAS BASIN

Basinwide Conditions Assessment
The SWSI value for the month was 2.7. The Natural
Resources Conservation Service reports that May 1
snowpack is 131 % of normal. Flow at the gaging station
Arkansas River near Portland was 750 cfs, as compared to
the long-term average of 426 cfs. Storage in Turquoise,
Twin Lakes, Pueblo, and John Martin reservoirs totaled 98%
of normal as of the end of April.

Outlook
The Lamar Canal called for water from John Martin
Reservoir prior to April 1, 2008; consequently the distribution
of conservation storage into accounts per the 1980
Operating Agreement for John Martin Reservoir began on
the above date at 00:00 hours. Total storage from
November 1, 2007 through April 30, 2007 distributed into
accounts in John Martin Reservoir was approximately a net
of 28,234 acre-feet. This storage volume was considerably
smaller than last year when the conservation storage total
was over 50,000 acre-feet and indicates the large difference
in low elevation snowpack between the 2006-07 winter and
the 2007-08 winter. The Arkansas River call started at Fort
Lyon Canal's second water right (3/1/1887) and ended on
Amity Canal's senior water right (2/21/1887).

Administrative/Manaqement Concerns
A significant amount of planning has occurred to
prepare for higher than average runoff in 2008. The falling
snowpack numbers through April alleviated some concerns,
but the snowpack remaining still indicates a good runoff.
Multiple meetings with a large number of municipal entities
and the Bureau of Reclamation and Army Corps of
Engineers were conducted to review operations that make
room in upper reservoirs (Twin Lakes and Turquoise) by
moving water to Pueblo Reservoir. These operations pushed
Pueblo Reservoir to near spill and caused a number of
entities to make decisions regarding water at risk of spill.
Winter carry-over water was called for by the ditches with
water in Pueblo Reservoir for use prior to the end of April.
Preliminary compliance model results (H-I Model)
produced by Colorado experts at the end of March indicated
that the well associations in the Arkansas Basin were
successful in providing adequate replacement water to the
river and to the Offset Account in John Martin Reservoir to
keep Colorado in compliance with the Arkansas River
Compact for the ten-year accounting period from 1998-2007.
Kansas experts have until May 15, 2008 to review the model
results and provide any revisions.

May-08

ARIWS6S BASlN9/lS HSTCRY

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ARKANSAS RIVER NR PORTLAND, FLOW BY WATlER YEAR

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REPRESENT A TlVE RESERVOI RS

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John Martin

Pueblo

Turquoise

Tv.in Lakes

II Avg. 4/30 Contents

114130'08 Contents

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