7246

• UCREFRP Catalog Number: 7246
• Author: Pucherelli, M. J. and R. C. Clark.
• Title: Memo - February 9, 1990, Green River Backwater Habitat Mapping; Fluctuating Flow Test, Utilizing Airborne Videography Techniques ‎(Endangered Fish)‎.
• USFW Year: 1990.
• USFW - Doc Type: Denver, Colorado.
• Copyright Material: NO

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UNITED STATES GOVERNMENT

memorandum

TO

Memorandum
: Head, Remote Sensing Section

Denver, Colorado
DATE:
February 9, 1990

FROM : Michael J. Pucherelli, Environmental Biologist
Richard C. Clark, Advanced Sciences Inc.

SUBJECT: Green River Backwater Habitat Mapping; Fluctuating Flow Test, Utilizing
Airborne Videography Techniques. (Endangered Fish)

Applied Sciences Referral Memorandum No. 90-4-4
.

Principal Investigator: Michael J. Pucherelli

Background

Following the construction of Flaming Gorge Dam in 1962, the abundance of
endemic fish species in the Green River has decreased. These species
include the endangered Colorado squawfish (Ptychocheilus lucius) and
humpback chub (Gila cypha), and the rare but unlisted razorback sucker
(Xyrauchen texanus). The dam has altered the natural state of the Green
River by reducing flood events and their severity, increasing late fall and
winter fluctuations and in general altering natural flows throughout the
year (Tyus et al., 1987). Studies conducted by the U.S. Fish and Wildlife
Service (FWS) have concluded that backwaters in the Green River serve as
important nursery habitat for young-of-the-year Colorado squawfish
(Tyus et al., 1987, Tyus and McAda, 1984). The Remote Sensing Section of
the U.S. Bureau of Reclamation (Reclamation) has been studying the utility
of remote sensing techniques and the effects of Flaming Gorge Dam releases
on downstream fish habitat in the Green River since summer, 1986 (Pucherelli
et al., 1988, 1989, Pucherelli and Clark, 1989).

A pilot study was developed in 1986 using color infrared photography and
Geographic Information Systems (GIS) techniques to examine backwater
availability in response to different Green River flows. The pilot study
was considered successful, and in 1987 an expanded study was initiated which
examined the relationships between seven different flows, and backwater area
and number, at five sites on the Green River in Utah. During 1988, a study
was designed to test the effect of fluctuating flows on backwater habitat in
the Green River. However, extremely low-flow conditions produced by drought
did not allow the study to be conducted. Alternatively, the stable low-
flows of 1988 presented a unique situation to establish a relative baseline
condition for riverine habitat during flows approximating a "normal" summer
hydrograph for the Green River from about Island Park to the confluence with
the Colorado River. Therefore, it was decided to conduct a fluctuating flow
study on the Green River during 1989.

Although aerial photography is currently thought to be the optimum method
for mapping and determining various riverine habitat, the cost of this
method is prohibitive for extensive studies. Consequently, a more