8194

• UCREFRP Catalog Number: 8194
• Author: Smith, G. R. and R. G. Green.
• Title: Flaming Gorge Consolidated Hydrology Report.
• USFW Year: 1991.
• USFW - Doc Type: Denver, Colorado.
• Copyright Material: NO

4.0 MONTHLY FLOW MODEL

~ 4.1 Introduction and Background

In anticipation of the development of a Biological Opinion for Flaming Gorge
operation, the Service has developed a monthly flow model of the Green River
up to and including Fontenelle Reservoir. The model will be used to determine
the effects of the current operation and any changes in operation in
accordance with Section 7 of the Endangered Species Act (50 CFR 402). The
development of the model has been a joint effort by the Service and
Reclamation. Reclamation has provided the Service with the model and has
provided most of the information setting up the model. Reclamation has also
provided input into developing target elevations for the reservoir and has
reviewed model output to insure that the reservoir is operating as expected
[1].

The model being used by the Service is version 3.0 of the HYDrological River
Qperations ~tudy ~stem (HYDROSS) model. HYDROSS was developed by
Reclamation's Billings office and was provided to the Service for testing and
use in the Upper Colorado River Basin. The advantage to HYDROSS 3.0 over
previous versions is that it uses more sophisticated reservoir operation
schemes, and has the capability of balancing reservoirs based upon user input
capacity targets. HYDROSS 3.0 is a system of computer programs for conducting
monthly water supply studies along traditional accounting lines. The system
allows the user to evaluate many operational scenarios by varying the physical
and operational parameters of the model [2].

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4.2

Objectives

The primary objective for the development of a model was to evaluate the
operation of Flaming Gorge Reservoir under differing operational scenarios.
These scenarios will be developed as the work on the Opinion progresses and
will have as their ultimate goal the improvement of habitat conditions for
endangered Colorado River fish.

A second objective was to have an
for cumulative effects analysis.
process and HYDROSS has been used
Colorado River.

accounting model to track project depletions
This is an important aspect of the Section 7
for several consultations on the mainstem

A third objective was to provide the Service with a comprehensive model of the
upper Green River which accurately reflects monthly flow conditions at
locations which are important for endangered fish research.

A fourth objective was to have a model which could quantify effects of
differing development scenarios on power operations.

A fifth objective was to implement a new version of the HYDROSS model which
has enhanced reservoir operation capabilities.

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4-1