[Awclist] [Fwd: [Riveraccess] State of the Colorado Ecosystem Presentation In Flagstaff Nov 2 - GCPBA Newswire]

[Thomas Robey]

-------- Original Message --------
Subject: 	[Riveraccess] State of the Colorado Ecosystem Presentation In 
Flagstaff Nov 2 - GCPBA Newswire
Date: 	Mon, 31 Oct 2005 16:47:30 -0700
From: 	Richard Martin <leigh at sedona.net>
To: 	gcpbaonline <gcpba at yahoogroups.com>
CC: 	riveraccess at multi.hydrosphere.com, utahriversports at yahoogroups.com


*State of the Colorado Ecosystem Presentation In Flagstaff Nov 2 - GCPBA 
Newswire - Oct 31, 2005

Wednesday, November 2, 2005
Assembly Hall, Cline Library, Northern Arizona University
6:30 to 9 pm, Free

*Scientists from Northern Arizona University (NAU) and the U.S. 
Geological Survey (USGS) will make a free public presentation of the key 
findings presented in /The State of the Colorado River Ecosystem in 
Grand Canyon/, a comprehensive report that details the impacts of the 
operation of Glen Canyon Dam and other management actions on downstream 
resources within Grand Canyon National Park. Presentations will examine 
the condition of native fish, sediment resources, camping beaches, and 
cultural resources from 1991 through 2004. The event is cosponsored by 
the NAU Department of Geology and the USGS Grand Canyon Monitoring and 
Research Center. Free copies of the report will be available at the event.

(GCPBA Thanks to Lynn Hamilton, GCRG for the notice)

*News Release*
October 25, 2005 Stephanie Hanna (206) 331-0335 shanna at usgs.gov
*Adaptive Management Key to Protecting Colorado River Ecosystem in Grand 
Canyon*

Today, the USGS released /The State of the Colorado River Ecosystem in 
Grand Canyon/, a comprehensive report that details the impacts of the 
operation of Glen Canyon Dam and other management actions on downstream 
resources within Grand Canyon National Park.

The 220-page report assesses scientific studies of aquatic, riparian, 
fish, sediment, recreation, and cultural resources from 1991 through 2004.

The report was prepared at the request of the Glen Canyon Dam Adaptive 
Management Work Group (AMWG), a federal advisory committee that makes 
recommendations to the Secretary of the Interior on the operation of 
Glen Canyon Dam and other management actions. The USGS report and other 
pertinent data, including the results of the November 2004 High-Flow 
Experiment, not included in this report, will be used by the AMWG to 
assess current practices and make recommendations to the Secretary.

“We live in an age when science allows us to clarify what is happening 
in complex natural systems like Grand Canyon,” said Dr. Ted Melis, 
Acting Chief of the GCMRC and one of the report’s authors and editors. 
“This report proves the vital importance of science-based adaptive 
ecosystem management. Its analysis and results can help managers fine 
tune dam operations and identify other actions to benefit downstream 
resources, from native fishes to camping beaches, that the public values 
in Grand Canyon.”

The major findings are:


• Under current dam operations, the Colorado River transports more sand 
out of the system than is supplied by tributaries on a seasonal to 
annual basis (that is, export exceeds input), preventing multi-year 
accumulation in the channel. As a result, erosion of channel and sandbar 
deposits from Marble and Grand Canyons continues.


• Since the report was finalized, scientists have continued to evaluate 
the results of the November 2004 High-Flow Experiment. One of the most 
surprising findings was the robust increase in sandbar area and volume 
in upper Marble Canyon, which has historically been one of the most 
sediment limited reaches of the river. These more recent findings 
suggest the use of short, strategically timed high-flow releases 
following sporadic sand inputs from tributaries is a possible strategy 
for rebuilding beaches and sandbars.


• The number of federally endangered adult humpback chub (/Gila cypha/) 
in the Grand Canyon ecosystem has declined since at least the late 
1980s, which is in part the result of a reduction in the rate of young 
chub surviving long enough to reach spawning age.


• Nonnative rainbow trout (/Oncorhynchus mykiss/) in the Lees Ferry 
reach and downstream as far as river mile 75 have proliferated under the 
modified low fluctuating flow alternative that governs day-to-day dam 
operations. Likewise, nonnative brown trout (/Salmo trutta/) have 
increased dramatically around Bright Angel Creek and upstream to above 
the Little Colorado River confluence (river mile 61). Both species prey 
on native fishes.


• Although there is no basis for claiming that the current operation at 
Glen Canyon Dam resulted in recent and repeated low recruitment and the 
continued decline of humpback chub, it is clear that the restrictions on 
dam operations since 1991 have not produced the hoped-for restoration 
and maintenance of this endangered species.


• Archaeological sites in the river corridor and locations of 
traditional importance to Native Americans continue to receive negative 
impacts from side channel surface erosion and recreational visitors. 
These processes are aggravated by the diminishing supply of sediment, 
which appears to be contributing to and exacerbating the rate and amount 
of erosion.


• Between 1998 and 2003, the area available for camping at 
high-elevation campsites used by summer recreationists decreased by 55 
percent and the average rate of decrease was 15 percent per year. The 
decrease in campsite area occurred both in Marble and Grand Canyons as 
the result of erosion and vegetation encroachment. As noted above, these 
areas appear to have benefited from the November 2004 High-Flow Experiment.

The report will be the focus of discussion at a USGS symposium in Tempe, 
Ariz., Oct. 25-27. USGS also will provide detailed information at the 
symposium on the results of the November 2004 High-Flow Experiment 
release from Glen Canyon Dam.

The release of the report also coincides with the tenth anniversary of 
the completion of the environmental impact statement required by the 
Grand Canyon Protection Act of 1992 and which set the stage for current 
operations at Glen Canyon Dam

The Glen Canyon Dam Adaptive Management Program is largely an outgrowth 
of the Grand Canyon Protection Act of 1992. It is administered by the 
U.S. Department of the Interior and facilitated by the Adaptive 
Management Work Group. The USGS Grand Canyon Monitoring and Research 
Center has responsibility for scientific monitoring and research efforts 
for the program.

To download the report go to www.gcmrc.gov/products/score/2005/score.htm.

The USGS serves the Nation by providing reliable scientific information 
to describe and understand the Earth; minimize loss of life and property 
from natural disasters; manage water, biological, energy, and mineral 
resources; and enhance and protect our quality of life.

To receive USGS news releases go to www.usgs.gov/public/list_server.html 
to subscribe.


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