WSP03460

• File Number: 8441.700
• Description: Colorado Big Thompson Project - Annual Operating Plans
• Basin: South Platte
• Water Division: 1
• Date: 1/1/1989
• Title: Annual Operating Plans - Colorado Big Thompson Project - Water Year 1989-1990
• Water Supply Pro - Doc Type: Report/Study

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recorded 12.5 inches on Ap...il 1, Willow Creek 8.2 inches on Ma...ch 1,
Granby 9.7 inches on March 1, and Lake Estes 8.4 inches on I~arch 1.
Pe...cent of normal ...anged from 84 pe...cent at the Green Mountain watershed
to 99 pe...cent at the Will ow C...eek watershed.

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Snow courses for wate...sheds within the P...oject averaged only 52 percent
of no...ma1 snowpack wate... content on May 1. All wate...sheds, except fo...
Green Mountain, received much below normal precipitation in April. The
Willow C...eek and Lake Granby watersheds reco...ded snow-wate... accumulations
on May 1 of only 32 percent of normal and 50 percent of normal,
respect i ve 1y. The May 1 snow-water content fo... the Green Mounta i n
watershed was 71 percent of normal. The Lake Estes watershed snow-water
content was 51 pe...cent of average on May 1.

Steady rainfall occurred in the Lake Estes a...ea during May 13 through
May 17 with 1.20 inches ...ecorded ove... the five days. Howeve....
precipitation continued to be below no...ma1 ove... the Project and averaged
only 63 percent of ave...age. Precipitation was below no...ma1 over the
Project a...ea in June, with Willow Creek and Lake G...anby at 73 percent of
average, Green Mountain at 72 percent of ave...age, and Lake Estes at 86
percent of average. July through September p...ecipitation was varied on
all wate...sheds. The Green Mountain watershed ...ecorded 111 percent of
ave...age p...ecipitation in July and only 42 pe...cent of average in
September. A total of only 3.89 inches of p...ecipitation was ...ecorded on
the Willow Creek and Lake G...anby wate...sheds f...om July through Septembe...
and this was 72 percent of average. Precipitation in the Lake Estes
area was near average fo... the three months, at 98 percent of average.

Tempe...atures were much above no...ma1 for the first three weeks of April.
Record tempe...atures were set in Denve... f...om April 21 through Ap...il 23
with 89", 88", and 85" ...espective1y, being ...ecorded. Temperatures were
above normal fo... May with record tempe...atu...es being set in Denver at
87" on May 7 (tied 115 year reco...a) and on May 23 at 93" (new ...ecord).
June temperatu...es were nea... ave...age but a record heat wave hit the
first week in July with Denver setting a reco...d of five consecutive
days of ove... 100".

for wate... year 1989, the mlnlmum reco...ded tempe...atu...es were -46"F at
Green Mountain Rese...voir on February 7, -41"F at Lake G...anby on February
7, and -35"F at Lake Estes on Februa...y 3. Overall, winter temperatures
we...e near normal for the water yea..., except for a very cold February.

Varied summe... tempe...atures we...e recorded over the enti...e Project, with
temperatu...es peaking in early July. The maximum tempe...atures was 89"F
on July 5 and 6 at Green Mountain Rese...voi.... The maximum temperature at
Lake G...anby occu...red on July 6 and was 85"F. and Lake Estes reco...ded a
maximum temperatu...e of 96"F on July 8.

Alva B. Adams Tunnel (Adams Tunnel) diversions totaled 276,700 ac...e-feet
(118 percent of ave...age) for the water year.

Seasonal wate... de1ive...ies (Novembe... 1988-Septembe... 1989) we...e 137 percent
of ave...age for the,Project.

Project generation for the wate... yea... was above average at 104 percent of
ave...age.

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