WSP00248

• File Number: 8220.101.09
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 10/1/1997
• Author: USDOI-BOR
• Title: Biological Assesment of the October 1997 Fall Test Flow from Glen Canyon Dam
• Water Supply Pro - Doc Type: Biological Opinion

be conducted, Additional observations will be made for impacts to Kanab Ambersnail habitat at
Vaseys Paradise (river mile 31), and potential trout stranding in the Glen Canyon reach,

Streamflow and sediment-transport data will be collected from stream gaging stations at Lees
Ferry, the cable way above the Little Colorado River (LCR) confluence, the Grand Canyon
station near Phantom Ranch, and at the mainstem gage above Diamond Creek, Additional
monitoring to detect aggradation of sandbars will occur at sites between GCD and Badger Rapids
(river miles -16 and 8), Daily photographs of previously monitored sandbars and camping areas
will provide before and after images that show impacts of the test flow at up to 32 sites,

A jointly coordinated post-flood river trip by members of the USGS, Northern Arizona
University, and Utah State University will document topographic changes and sedimentology of
new deposits at sites throughout the ecosystem; particular emphasis will be placed on sites
between the Paria River and the LCR. These data will be integrated with streamflow and
sediment samples collected during the flood in an attempt to provide an integrated assessment of
processes and resource response, These science efforts will hopefully answer the question as to
the flood's effectiveness, while building on the previously obtained knowledge base accumulated
from earlier experiments, including the 1996 test flow,

Although the short lead-time for conducting this October experiment, combined with its
implementation during Grand Canyon National Park's non-motor season, 1imits scientific
investigation to a large degree. the GCMRC believes that sufficient information will be gathered
during and after the test to provide stakeholders with needed infonnarlon. Every attempt to limit
use of motorized equipment for monitoring has been made, yet tight time constraints have
required the GCMRC to request permission from the National Park Service to launch one
motorized boat to support downstream monitoring.

National Environmental Policy Act

Reclamation examined the existing ErS, operating criteria, and other documents to detennine if
the flow proposed by the AMWG was in compliance with the National Environmental Policy Act
(NEP A), Reclamation staff also consulted with the Salt Lake City office of the solicitor, who
advised that the parameters of the proposed flow are within historically authorized operations, '
and no further NEPA comp1iance was required. However, while NEP A may not technically or
legally apply to the proposed tlow becaJl!e it is within the established authorized operational limits
for Glen Canyon Dam. the EIS ROD contains a statement in Section VI, Item I,titled Adaptive
Management, noting that the Adaptive Management Program includes:

"development of a long-term monitoring, research and experimental program which could
result in some additional operational changes. However, any operational changes will be
carried out in compliance with NEP A"

Reclamation therefore evaluated the proposed action for potential impacts and detennined that

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