WSP08901

• File Number: 8220.101.09
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 10/13/1993
• Author: USDOI-USFWS
• Title: Draft Biological Opinion-Operation of Glen Canyon Dam as the Modified Low Fluctuating Flow Alternative of the Draft Envronmental Impact Statement Operation of Glen Canyon Dam
• Water Supply Pro - Doc Type: Biological Opinion

. .

2,21-93-F-167

,'.
~:~

I:'

DRAFT BIOLOGICAL OPINION
MODIFIED LOW FLUCTUATING FLOW ALTERNATIVE
DRAFT ENVIRONMENTAL IMPACT STATEMENT
OPERATION OF GLEN CANYON DAM

INTRODUCTION

, I

This biological opinion is in response to Bureau of Reclamation's (Reclamation) February 5,
1993, request for formal section 7 consultation, under the Endangered Species Act of 1973, as
. amended, with the Fish and Wildlife Service (Service) on the proposed action to operate Glen
Canyon Dam according to operating and other criteria of the Modified Low Fluctuating Flow
Alternative (MLFF), selected as the preferred alternative for the Draft Environmental Impact
Statement (EIS), and described in the Preliminary Draft EIS, Operation of Glen Canyon Dam,
Glen Canyon Dam, shown in Figure 1, is located in Coconino County, Arizona.

~..

L:-'

The species of concern in this opinion are the endangered bald eagle (Haliaeerus leucocephalus),
humpback chub (Gila cypha), Kanab ambersnail (Oxyloma haydeni kanabensis) , peregrine falcon
(Falco peregrinus afllltUl1l), and razorback sucker (Xyrauchen texanus). No critical habitat has
"
been listed for the above speCies. Critical habitat was proposed for the humpback chub and the
razorback sucker on January 29, 1993; however, that listing is to be supplemented with further
documents that will be made available by the Service for public review (U,S. Fish and Wildlife
Service 1993a, 1993b). In addition, the southwestern willow flycatcher (Empidonax traillil
extimus) was proposed as an endangered species with critical habitat on July 23, 1993. Because
Reclamation is still evaluating the effect of the proposed action on the southwestern willow
flycatcher and more information will be released later on the proposed critical habitat for
endangered fish, the Service will address the section 7 responsibilities for those proposed species
and critical habitats in a later conference report.

;'\
r:,~
;~
c::\
:;~;::.

.-.'

<~~.

. ,

.~; ':

~'--j,

",'

The 9O-day consultation period began on February 8, 1993, the date your request was received
by our office. On April 27 the Service requested an extension of 20 days to allow time to
receive and review information we believed essential to the consultation. On May 5, 1993, your
Colorado River Studies Office allowed until May 18 for the Service to provide a biological
opinion or summary. A biological summary dated May 17 and a draft biological opinion dated
May 20 were provided to Reclamation.

Ce,

:::)i;

;~:;,~
;i~
"'1
fti

;-~

~,;--. '

Reclamation and Service met May 21, 1993, to discuss the reasonable and prudent alternative
contained in the draft biological opinion. Reclamation requested a technical review of
recommended flows. That review was conducted by the Glen Canyon Environmental Studies
(GCES) Senior Scientist and Program Manager on June I I. The Service's overall impression
of that meeting was that the researchers supported the recommended flow scenario that better
represent the pre-dam hydrograph in which the native fishery is adapted to. In a June 10
. memorandum, Reclamation confirmed the mutual agreement to extend the consultation period

13 Clct.clMr 1993 Draft biological opinion 2-21-93-F,167

1