7239

• UCREFRP Catalog Number: 7239
• Author: Smith, G. R. and R. G. Green.
• Title: Flaming Gorge Consolidated Hydrology Report -Draft.
• USFW Year: 1990.
• USFW - Doc Type: Denver, Colorado.
• Copyright Material: NO

5.0 PEAKING OPERATIONS OF FLAMING GORGE

5.1 Study Objectives

The study objective were, (1) to develop an hourly hydraulic model which can
be used to quantify the effects of peaking operations on the Green River
below Flaming Gorge Reservoir. 2) Provide data, and analyses to biologists
and decision makers on the effects of proposed changes in Flaming Gorge
operation to backwaters down stream. 3) To facilitate the development of the
Flaming Gorge Biological Opinion by adding to the hydrological knowledge of
endangered fish needs.

5.2 Introduction and Background

Recent studies by the Service have identified backwater nursery habitat for
young-of-the-year Colorado Squawfish in the Green River Basin. Consequently
the size, distribution and abundance of backwater habitat has been the focus
of several studies. The Flaming Gorge Peaking Power Study was an outgrowth
of the need to quantify the effects on backwaters in the Green River. The
Peaking Power study was designed to evaluate. various fluctuating flow
conditions on backwaters and to quantify effects in terms of both flow and
stage.

The "tool" the Service chose to use for the study is the ~treamflow ~nthesis
And Reservoir Regulation (SSARR) model [1]. The SSARR model has the
capability to route water released from a reservoir and to calculate the
amount of attenuation of flows at calibrated locations down stream. The
model uses observed hydrographs at the upstream and down stream locations to
calibrate three variables (total time of storage, number of routing phases,
travel time) in a routing/attenuation algorithm. These variables are
adjusted until the observed hydrographs are replicated. Calibration work is
largely a process of trial and error methods of adjusting until, on the
average, simulated streamflow matches observed streamflow.

The basin routing program which was used in the Flaming Gorge Peaking Power
study consists of three routing parameters, time of storage, number of
routing phases and travel time. These three routing parameters are adjusted
for each component of flow until, on the average, the rising limbs, peaks,
and recession flows of the simulation matches observed hydrographs. Final
shaping of stream flow hydrographs are achieved by separately plotting
calculated and observed hydrographs and adjusting routing parameters as
needed. The "goodness of fit" between calculated and observed hydrographs
indicates the capability to reproduce observed events [2].

Based upon Reclamation's ongoing work with the SSARR model on the Green
River, the Service opted to use SSARR for the peaking power analysis for the
Opinion. This was based upon the ready availability of the model and the need
to have flow and stage information at or near habitat sites. The Service
chose three additional sites to be added to the SSARR network for the Opinion
analysis. These sttes were located at Mitten Park in Dinosaur National
Monument, Ouray National Wildlife Refuge, and at Tia Juana Bottom below the
confluences of the White and Duchesne Rivers (see Figure 5-1). The site at

5-1