DWR_4151888

• Title: JUNE 1994 SWSI: COLORADO WATER SUPPLY CONDITIONS UPDATE, SURFACE WATER SUPPLY INDEX
• Year: 1994
• Document Type - Publications and Reports: SWSI Monthly Report

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SOUTH PLATTE BASIN
r Basinwide Conditions Assessment:
The SWSI value of 2.6 indicates that for May the SOUTH PLATTE RIVER BASIN
asin water supplies were above normal. Reservoir storage, S Sur'"`**tor Supply "nosx"I itorY
the key component in this basin in computing the SWSI value, 4 .
was 107% of normal on May 31. Storage in the major plains w 3 l 1_reservoirs, Julesburg, North Sterling, and Prewitt, decreased `
by 4,373 acre-feet during May and are at 88% of capacity. 2 M q- , •1[ a ? iStorage in the major upper basin reservoirs, Cheesman,Eleven 1 -- E
Mile, Spinney, and Antero, increased by 11,384 acre-feet and o D vir-Ibric,--..-
-
are at 94%of capacity. The National Weather Service reports - _,
basin precipitation as 56% of normal during May. The mean
a _2
daily flow of the South Platte River at the Kersey gage was
585 cfs, as compared to the 1961-1993 May average of 2,264 3
cfs. Flow at the Colorado/Nebraska state line averaged 86 cfs. -4
JAN85 JANB6 JANB7 JAN68 JAN89 JAN90 JAN91 JAN92 JAN93 JAN94
Except for severe short duration storms in isolated MONTW YEAR
areas, May was very dry over the whole basin. The snowpack
went from slightly less than average for most of the basin to
significantly below average in the whole basin. Nevertheless,
the flows in most streams were approximately average due to
the warm weather and resulting early runoff. The calls on the SOUTH PLATTE RIVER NR KERSEY
FLOW BY WATER YEAR
South Platte main stem were similar to years past. 2 8
2 6 43
Outlook 2.4
2.2
The warm weather has created peak runoff flows a , 2
week to ten days earlier than most years. This creates a 1.B
concern that flows for the remainder of the summer will be
0_ 1.4
less than average. In addition, the early runoff will likely W- ,.2
reate a senior call situation earlier than average. Fortunately, sv 1
'servoir levels are average to above average and will be able g
to make up some of the short falls in river flow. As always, 0 4
predictions are dependent on rain conditions. Significant 0 2-
rains could still make this a normal or even above normal year u
'--' 1
Oct NDV Dec Jan Feb March Aprll May June July Aug Sept
for river flow. Barring above average rain, this will be a MONTH
p WET(1963) o DRY(1964) p AVG X 1994
below average year for stream flow.
Administrative/Management Concerns
The dry conditions will require good communications
between water administrators and water users. REPRESENTATIVE RESERVOIRS
The Forest Service has delayed their decisions 240 SOUTH PLATTE RIVER BASIN
concerning permits for several structures, primarily reservoirs 220,/
in the Poudre basin, pending receipt of an opinion from the 200
Fish and Wildlife Service concerning impacts of issuing the i 150
permits and further discussions with the cities and others ;• 160 /�/�\\\
�in 140✓/�\� /
involved. The parties are looking for alternatives to meet the ▪ �� /
Forest Service goals for fish habitat and other purposes ion\\
without the requirement of bypass flows. The Forest Service e BD/ ,\
still anticipates making decisions concerning permit i 60
requirements this summer. ,D /\ 7
The Technical Advisory Committee of the Metropolitan 20,�/^,.,\ //\ /7\ //��\ %/j�\ i
Water Supply Investigation met during May to develop a plan I //
Dll1On Fbreetooth Eleven Mlle Cneeenen Jackcon Barr Lake
of action to study water supply opportunities for front range ® Avg S/31 Contanta f\-N 5/31/94 Contents
growth. Work groups were formed to define the scope of
etudy to be followed in the future by contract water
nsultants. The four supply opportunities identified include
interruptable dry year supply, system integration, effluent management, and conjunctive use.
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