WSP10855

• File Number: 8200.760
• Description: Yampa River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 8/13/1993
• Author: Various
• Title: Results of New Model Runs - Elkhead Enlargement Study
• Water Supply Pro - Doc Type: Data

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001313

MEMORANDUM

TO:
FROM:
SUBJECT:
DATE:

Technical Steering Group \~_" __
Chuck Brendecke, Ed Armbruster
Results of New Model Runs - Elkhead Enlargement Study
August 13, 1993

Enclosed are the results of the new model runs that were specified at the July 7 TSG
meeting. The enclosed graphs and tables depict summary information (total shortages,
contemplated draft, reservoir contents, flow at Maybell) for 6 scenarios. We will discuss these
runs at the August 18th meeting in Glenwood.

Scenario I assumes 1989-level demands with the Juniper Project operated in its correct
(1954) priority position. There are no reservoir enlargements assumed and storage supplies are
available only to existing contract holders. No refills of any reservoirs permitted. In keeping
with the 1989-1evel demand assumption, the Hayden and Craig station demands are set at the
"1989 potential" level rather than the levels from the Biological Opinion.

Scenario II assumes 1989-level demands with the Juniper Project operated in a
subordinated priority position. There are no reservoir enlargements assumed and storage
supplies are available only to existing contract holders. There are no refills permitted, The
Hayden and Craig station demands are set at the "1989 potential" level.

Scenario III assumes 2040-ievel demands with the Juniper Project operated in a
subordinated priority position. The Hayden and Craig stations are assumed to exert the
Biological Opinion demands. Elkhead and Stagecoach reservoirs are assumed to be enlarged
but not allowed to refill.

Scenario IV assumes 2040-level demands as in Scenario III. The Juniper Project is
operated in a subordinated priority position. The enlarged reservoirs are assumed to have an
unlimited refill right.

Scenario V assumes 2040-level demands as in Scenarios III and IV. The Juniper Project
was operated in its correct priority position to define the contemplated draft. This draft was
then converted to a 1954 instream flow right and subsequently reduced (iterative solutions) by
the amount of storage draft of the enlarged reservoirs. The enlarged reservoirs are operated to
augment juniors called out by the 1954 instream right. No refills of the enlarged reservoirs are
permitted.

Scenario VI is the same as Scenario V except that the enlarged reservoirs are assumed to
have an unlimited right to refill.

In all scenarios the administration of storage decrees accounts for carryover on the start-
fill date of the reservoir (Nov 1 for Juniper, Feb 1 for all others). The De~dman Bench and
power decrees are "stacked" rather than operated in series. We also made some refinements in
the priority orderings of junior water rights to more accurately reflect the effects of a 1954
call. .

If you have any questions on these results that you would like to raise before our
meeting, feel free to give us a call.

Hydrosphere Resource Consultants 1002 Walnut Suite 200 Boulder, Colorado 80302
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