SWSIReportApril2008

• Title: Colorado Water Supply Conditions Update
• Date: 4/15/2008
• Description: Joint Water Availability & Colorado Flood Task Force Meeting Presentation
• Basin: Statewide
• Drought Mitigation - Doc Type: Presentation

SAN JUAN/DOLORES BASIN

Basinwide Conditions Assessment
The SWSI value for the month was +3.0. The Natural
Resources Conservation Service reports that April 1
snowpack is 126% of normal. Flows at the Animas River at
Durango averaged 505 cfs (168% of normal) with a maximum
average daily peak flow of 812 cfs on Mar. 28th. Storage in
McPhee, Vallecito, and Lemon reservoirs totaled 103% of
normal as of the end of March.
The Dolores River at Dolores averaged 273 cfs
(205% of normal) with a maximum average daily peak flow of
641 cfs on Mar. 29th. The La Plata River at Hesperus
averaged 23.1 cfs (144% of normal) with a maximum average
daily peak flow of 83 cfs on Mar. 29th. Precipitation in
Durango was 0.08 inches for March which is below the 30-
year average of 1.79 inches. Precipitation to date in
Durango, for the water year, is 13.33 inches which is above
the average of 9.95 inches. Temperatures were normal for
the month. Durango was 1.20 above its 30-year average high
and right at average for the 30-year average low.
At the end of the month Vallecito Reservoir
contained 39,175 acre-feet compared to its normal contents
of 55,524 acre-feet (71 % of normal). Vallecito Reservoir
began releasing water in early February to prepare for the
expected above average inflows. McPhee Reservoir was up
to 298,350 acre-feet compared to its normal contents of
270,698 acre-feet (110% of normal), while Lemon Reservoir
was up to 23,629 acre-feet as compared to its normal
content of 20,391 acre-feet (116% of normal).

Outlook
Very little precipitation and normal temperatures was
the major theme of March 2008. With only 0.08 inches of
precipitation in March it ranked as one of the lowest monthly
totals on record for the last 112 years (108 of 112). Above
average flows are still expected throughout the basin this
spring and summer. To date the total snow-water-equivalent
within the basin has exceeded the average snow-water-
equivalent for the year with the average peak date occurring
in April. The NRCS data on March 31, 2008 reported a
snow-water-equivalent of 126% of average. The Pine River
Water Conservancy District continues to release water from
Vallecito Reservoir to ensure there is enough available space
to hold the spring runoff.

Administrative/Manaqement Concerns
The compact period on the La Plata between
Colorado and New Mexico began on February 15th, but
remained off compact call for the month. The compact
requires that half the flow at the upper index gages
(Hesperus and above) must be delivered across the Stateline
the following day. The low level snow melting in the La Plata
River basin has kept the flow at the Stateline well above the
flows at Hesperus.

Public Impacts
McPhee, Vallecito and Navajo reservoirs all began
or continued to ramp up releases in preparation for the
expected above average rivers flows this spring.

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9

Apr-08

SAN J..IIIN.lXl.rnESB\SIN9JIS HSTCRY

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M:N1H/YEAR

ANMAS RIVER NR DURANGO, FLOW BY WATER YEAR

2OJ,000
180,000

20,000

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Cct

Nov

Dee

Jan

Feb

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--8- V\ET (1973)

-+- DRY (2OJ2)

~AVG

"*- 2008

REPRESENT A TlVE RESERVOI RS

4OJ,000

350,000

3OJ,000

50,000

o

McPhee Vallecito Lemon

11II Avg.3I31 Contents 113131/08 Contents