WSPC05826

• File Number: 8283.200
• Description: Colorado River Basin-Colorado River Computer Models-Colorado River Decision Support System
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/26/1995
• Title: MODSIM Model-CRDSS Task Memorandum 1.15-27-Phas II-Calibration of MODSIM Prototype
• Water Supply Pro - Doc Type: Report/Study

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CROSS
TASK MEMORANDUM 1.15-27
PHASE II

Calibration of MOOSIM Prototype

1.0 ISSUE

The purpose of this task memorandum is to generally describe and document the procedures used
to calibrate the MODSIM computer model, developed as the prototype Water Rights Planning
Model (WRPM) for the Gunnison River basin. Calibration is necessary to establish credibility of the
model performance and to ensure that the model of the river system is producing accurate data.

2.0 DISCUSSION

2.1 General
For the purposes of the CROSS, calibration is accomplished by a comparison of the model
simulation results to measured historical data available from the U.S.G.S. and the Division of Water
Resources (stream gage data, reservoir storage contents, diversions at key structures, etc.). In
order to replicate historic hydrologic conditions in the Gunnison River basin, the results from the
model simulation for the "good neighbor" protocol were used in the calibration. As opposed to
river administration in strict accordance with the priority system, the good neighbor protocol
reflects a number of informal agreements among the major water users and the Division Engineer
that are intended to maximize beneficial use of water within the basin by limiting an administrative
"call" by senior water rights against junior water rights in the Gunnison and Uncompahgre river
basins.

The model calibration was focused on the eleven year period, 1980 through 1990. This period
was selected because it represents both wet and dry year hydrologic conditions and is recent
enough to reflect the operations of most of the major storage and diversion facilities in the basin,
with the exception of Ridgway Reservoir (1988).

2.2 Calibration Points
The following stream gages, reservoirs and key water right structures were selected for the
comparison of historic versus model simulated data:

Stream Gaaes:

Gunnison River at Gunnison; Gunnison River at Delta; North Fork of
Gunnison near Somerset; Uncompahgre River at Colona; Uncompahgre River
at Delta; Gunnison River near Grand Junction.

Reservoirs:

Blue Mesa Reservoir; Taylor Park Reservoir; Ridgway Reservoir; Paonia
Reservoir.

Kev Structures:

Gunnison Tunnel (South Canal); North Delta Canal; Bonafide, Relief and
Hartland ditches (aggregated); Fire Mountain Canal; Loutzenhizer Ditch; Selig
Ditch;

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1.16-27 Foshs, Ritsch