DWR_4151795

• Title: JUNE 1991 SWSI: COLORADO WATER SUPPLY CONDITIONS UPDATE, SURFACE WATER SUPPLY INDEX
• Year: 1991
• Document Type - Publications and Reports: SWSI Monthly Report

•
e .
• SOUTH PLATTE BASIN
Basinwide Conditions Assessment:
The SWSI value of +0.7 indicates that the overall SURFACE WATER SUPPLY INDEX
conditions are slightly above normal. Reservoir storage, the s South Platt.Flwr Beeln
key component in this basin in computing the SWSI value, 4_
was 100% of average on June 1. Storage in the plains - 3 .1 > :z w
reservoirs decreased by 14,200 acre-feet for the month. With
the exception of Cheesman and Spinney Mountain Reservoirs 1-
which are at 69%and 41%of capacity respectively,storage is 1- . �1-.,;
at or near capacity. Precipitation was 105%of average for the 1 o � -- =--'-.1
month and is 84% of average for the water year. The Denver 11:2:11171-Pill .
-,-
metropolitan area received an average of 2.43 inches of 2 1
precipitation for the month, compared to the average for May a
of 2.47 inches. Basinwide snowpack decreased to 39% of 'J
average. Snowpack is nearly totally diminished in the St
JAN62 JAN63 JANW JANS5 JAN66 JAN6: JaN611 JAN66 JANOO JAM
Vrain drainage. Flow at the key gaging station, South Platte MONTH?YEAR
River near Kersey, averaged 488 cfs for the month as
compared to the historic monthly average of 2442 cfs. Flow
at the Colorado/Nebraska stateline averaged 103 cfs for the
month. Ground water recharge projects continue to operate
including the Julesburg recharge project which is aimed at SOUTH PLATTE RIVER NP. KERSEY
EN
augmenting well pumping. _ FUR! WATER Yup
2.6 4?
2.4
Outlook:
Lower elevation snowpack is nearly totally i 2
diminished. This condition, along with cooler than normal 1 1.a
temperatures, has resulted in low runoff. The streamfiow ,e ,.8
forecast is lowest in the Cache la Poudre drainage at 73%of ,Lu 12
average and highest in the Bear Creek drainage at 100% of ; 1 •
average. Irrigation began earlier•than normal this year in -
0.8
Division 1 bringing senior direct diversion rights into play.
0.4
End of May precipitation events decreased direct diversions 0.2 -
and provided for some storage to take place. 0 .
OCt NOV Doc Jan Feb AYrCh AprII flay June July Aug Slot
AONTH
0 MET C1e113] + ORI C19E43 O AvG. A 1881
Administrative/Management Concerns:
The interstate compact with Nebraska adjusted on
April 1st,basically requires Colorado to provide a minimum of
120 cfs at the Colorado-Nebraska stateline. The primary river
call for the month was the Burlington diversion (November South Platte Basin Reservoir Supp I i es
20, 1885). The call dropped to the Independent diversion 240
right (November 20, 1876) between May 11 and 13. The 220, �
Cheesman storage right (June 27, 1889) went into effect on
May 24. Precipitation in late May allowed for the District 1 i
reservoir right (December 31, 1929) to go into effect on May 160
r` 140
30. g 120J�/��\
$v 100 J/ \}
Public Use Impacts:
- 60 / \
Public water use should be relatively normal. Flow in s 60
the reaches of the South Platte River immediately below 40
Spinney Mountain Reservoir and Cheesman Reservoir are at //\ �/ � �/� ///� /7
31 cfs and 48 cfs,respectively. Storage in Spinney Mountain
0-
DI l Ion N7reetooth Eleven Mlle Cheeeneln Jackson Barr Lake
Reservoir was 26,938 acre-feet on June 1, 1991. This
represents a net increase in storage for the month of 6,056 ® A"°' '"'`onLent. GM 5r31,91 Contents
acre-feet. Storage commenced on May 1, 1991, as in-stream
storage rights went into effect and Homestake transmountain
water deliveries began.
3