SWSIReportNov2006

• Title: Colorado Water Supply Conditions Update
• Date: 11/20/2006
• Description: Water Availability Task Force Meeting Presentation
• Basin: Statewide
• Drought Mitigation - Doc Type: Presentation

SOUTH PLATTE BASIN

Basinwide Conditions Assessment
The SWSI value for the month of October was 1.5.
Reservoir storage in Dillion, Horsetooth, Eleven Mile,
Cheesman, Jackson, and Barr Lake, the major component in
this basin in computing the SWSI value, was 1040/0 of
normal as of the end of October. Flow at the gaging station
South Platte River near Kersey was 682 cfs, as compared to
the long-term average of 662 cfs. Flow at the
Colorado/Nebraska state line averaged 53 cfs.

Outlook
October continued warm and dry through most of
the month. Thus, irrigation uses and calls continued until the
last week of the month. Wetter conditions the last week
allowed for some storage and recharge to occur for a few
days. Nevertheless, reservoir levels for agriculture
continued far below average with many of the plains
reservoirs either empty or near empty by the end of the
month. Overall storage in the major reservoirs east of
Kersey was only 120lb full at the end of the month. This is
nearer the 20/0 full at the end of October, 2002 than it is the
360/0 full at the end of 2005. It will be difficult to fill all of the
irrigation reservoirs next year without a significant snow pack
and wet spring conditions in 2007. Of note, farmers in the
Poudre basin are also very vulnerable as storage in this
basin is far below average after a very dry year.
Unlike the reservoir storage for the farmers, the
municipal reservoir situation is much better than 2002,
especially for reservoirs that feed the Denver metro area.
Major Denver Metro Supply Reservoirs were at 900/0 of
capacity. This compares favorably to a 500/0 capacity at the
end of October, 2002 and even with the 860/0 capacity at the
end of October, 2005.

Administrative/Manaqement Concerns
The better storage conditions are due to record
diversions from the west slope because of the very high
spring snowpack in the Colorado basin in 2006 and
generally wetter conditions at the south end of the South
Platte basin during the spring and summer of 2006.
Municipal suppliers north of Denver metro area have
adequate water storage supplies available though generally
not in quite as plentiful a situation as exists for the metro
area.

Nov-06

8JUTH PLATTE BASIN SV\JE!). HISTORY

I-
W
S 1.0

W
:J
<(
> 0.0
CiS
~

>- -1.0
~

Jan-97 Jan-98 Jan-99 Jan-OO Jan-01 Jan-02 Jan-03 Jan-04 Jan-OS Jan-OO
rvlCNTH / YEAR

SOUTH PLA TIE RIVER NR. KERSEY, FLOW BY WATER YEAR

700,000

600,000

ill
0)
LL
~ 500,000
u
<(

~- 400,000
---l
LL
W
2:: 300,000
I-
<(
---l
~ 200,000
:J
U

100,000

o
Oct

Nov

Dee

Jan

Feb

March

April

--e- WET (1983)

--+- DRY (1964) ---tr-AVG

~ 2007

REPRESENTATIVE RESERVOI RS

300,000

250,000

(j)
~ 200,000
~
<Il
0)-
~ 150,000
o
U5
0)
:0
m 100,000
::J

50,000

Dillon Horsetooth Eleven Mile Cheesman Jackson Barr Lake

II Avg.10/31 Contents

1110/31/06 Contents

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