Temperature Control Device Workshop

January 22-24, 2001

Saguaro Lake Ranch

Mesa, Arizona

PRELIMINARY SUMMARY OF FINDINGS

Compiled by Dennis Kubly

PURPOSE:

The purpose of this workshop was to evaluate ongoing research and monitoring being conducted

on the Colorado River Ecosystem (CRE), as defined by the Glen Canyon Dam Adaptive

Management Program (GCDAMP), and to determine what modifications or additions should be

made to the existing efforts to evaluate the effects of a temperature control device (TCD) on the

dam, should the decision be made to construct and operate the device. Recommendations from the

workshop would be used by the Grand Canyon Monitoring and Research Center, the Bureau of

Reclamation, and other members of the GCDAMP in formulating and carrying out the scientific

investigations charged with assessing the environmental effects of a temperature control device.

Participants included individuals who are currently conducting, or have in the past conducted,

research and monitoring efforts in the CRE, individuals who have conducted research and

monitoring on other river systems in western United States, including regulated systems having

dams with TCDs, individuals who have served on peer review panels that have evaluated research

and monitoring efforts in the CRE, and resource managers engaged in management of resources

within the CRE. The findings contained in this summary should be considered draft findings,

because they have not been reviewed and commented on by the participants.

REPRESENTED:

• Grand Canyon Monitoring and

Research Center

• Fish and Wildlife Service

• Bureau of Reclamation

• Environmental Protection Agency

• National Park Service

• U.S. Geological Survey

• Arizona Game and Fish Department

• Utah Department of Natural

Resources

• Utah State University

• Arizona State University

• Colorado State University

• Northern Arizona University

• Argonne National Laboratory

• SWCA, Inc.

• Ecometrics Research

• Reservoir Environmental

Management

• Stevens Ecological Consulting

PRESENTATIONS:
January 2001 TCD Workshop March 13, 2001

Draft Summary of Findings Page 2

The workshop began with presentations on background information, modeling, and field research

and monitoring. Speakers were asked to provide, where appropriate to their subject, the following

information:

• Summary of variables being measured, 

• Frequency and intensity of measurements,

• Methods of analysis,

• Ability to detect change in those variables,

• Recommendations for changes or additions to assess effects of a TCD.

OVERVIEWS

Dennis Kubly, Bureau of Reclamation, Salt Lake City, Utah and Barry Gold, Grand Canyon

Monitoring and Research Center, Flagstaff, Arizona. The Glen Canyon Dam Adaptive

Management Program: an effort to understand and manage the Colorado River Ecosystem

in Glen and Grand canyons.

Barbara Ralston, Grand Canyon Monitoring and Research Center, Flagstaff, Arizona. Overview of

Long-term Monitoring of Biological Resources Along the Colorado River.

MODELING

Amy Cutler, Bureau of Reclamation, Salt Lake City, Utah. Predicted temperatures from Glen

Canyon Dam temperature control device alternatives using CE-QUAL-W2.

David Harpman, Bureau of Reclamation, Denver, Colorado. The effect of a temperature control

device on hydropower at Glen Canyon Dam.

Josh Korman, Ecometrics Research and Carl Walters, University of British Columbia, Vancouver,

Canada. Grand Canyon conceptual model and stock assessment results: implications for

experimental implementation of selective withdrawal from Glen Canyon Dam.

FIELD RESEARCH AND MONITORING

Susan Hueftle, Grand Canyon Monitoring and Research Center, Flagstaff, Arizona –Water quality

assessment in Lake Powell and the Colorado River.

Joe Shannon, Northern Arizona University, Flagstaff, Arizona. Assessing Aquatic Food Base

Patterns over the Past Decade in the Colorado River below Glen Canyon Dam.

Wayne Gustaveson, Utah Department of Natural Resources, Page, Arizona.. The Lake Powell

fishery.

Bill Persons, Arizona Game and Fish Department, Phoenix, Arizona. The Lee’s Ferry trout fishery.

Lew Coggins, U.S. Fish and Wildlife Service, Flagstaff, Arizona. Native and non-native fish

studies: Little Colorado River.

Rich Valdez, SWCA, Inc., Logan, Utah. Native and non-native fish studies: Colorado River

mainstream.

Larry Stevens, Stevens Ecological Consulting, Flagstaff, Arizona.. Riparian communities and

recreation.

SUMMARY OF GENERAL RECOMMENDATIONS:

Following the presentations, workshop participants held large group and small group discussions
January 2001 TCD Workshop March 13, 2001

Draft Summary of Findings Page 3

to develop recommendations for research and monitoring to assess the effects of the temperature

control device if it is constructed and operated. Some of those recommendations follow.

Monitoring and Management Actions Relative to the TCD

• Water temperature is modified as a consequence of modifying hydrology as evidenced in

the experimental flows of year 2000: the two physical parameters should be considered

together in planning and assessment of management actions

• Scientists need more lead time for design and implementation of research and monitoring

assessments; water managers and scientists need to work more closely in planning studies

For the present discussion, the group defined two types of monitoring, core monitoring and effects

monitoring. Evaluation of a TCD would require both types of monitoring. They were defined as

follows:

• Core Monitoring – function is to measure status and trends of high priority resources;

sampling schedule typically calendar driven; highly standardized, consistently applied 

methods and protocols, few changes once established

• Effects Monitoring – function is to measure environmental conditions and resource status

before and after management actions are taken; sampling schedule typically event driven,

set up to accommodate particular actions; more flexible methods and protocols

A vigorous discussion occurred in response to a suggestion that the existing sampling design for

lower trophic level resources (algae and invertebrates) is statistically biased, i.e. sampling sites

are not randomly selected and thus tests of significance can not legitimately be applied to the CRE.

The Environmental Protection Agency’s Environmental Monitoring and Assessment Program was

put forth as an approach that might be used in Grand Canyon. Further conversation revealed that

these same issues probably are present in sampling designs for physicochemical and fisheries

studies. Participants had very mixed opinions concerning the significance of this decision, but it

was clear that more discussion should occur before decisions on sampling designs are made for

research and long-term monitoring in the CRE.

Much emphasis on detecting change in high priority fish populations in Grand Canyon is shifting to

estimation of recruitment rate using a stock assessment and synthesis model. One complication of

this index is that the estimate of recruitment rate for humpback chub can not occur until 2-3 years

after initial marking. Since there is little year-to-year control over hydrology, the relationship

between reproductive success, recruitment rate, and dam operations often will be confounded by

intervening years of differing dam operations and, thus, hydrology. This discussion led to an

attempt to identify other indicators of system change for different ecosystem components being

measured in the CRE. The results of that exercise are contained in the following table:

Large Group Discussion on Indicators:
January 2001 TCD Workshop March 13, 2001

Draft Summary of Findings Page 4

TEMPORAL INDICATORS OF CHANGE

Early1 Mid Late

Physicochemical Water temperature

System metabolism

Allochthonous input

(reservoir) C:N

stable isotope ratios

Lower Trophic Phytobenthic &

macroinvertebrate

benthic biomass

New colonists

Phytobenthic

community

composition

Macroinvertebrate

community

composition

Rainbow Trout Reproductive

success, Growth,

New colonists

Sustained range

expansion, Growth,

Disease/ parasites,

Population estimates

Native Fish Change in

distribution,

Reproductive

success, Growth,

Small-bodied exotic

numbers, New

colonists

Sustained range

expansion, Growth,

Disease/ parasites,

Population estimates

Recruitment rate,

Second HBC

population,

Down- and delisting

of T&E

1

 Scale of time frames for these indicators will vary for the different resource categories

PRESENT STATUS OF TCD EVALUATION

In January 1999 Bureau of Reclamation released a draft environmental assessment on a

temperature control device for Glen Canyon Dam. The preferred alterative was a single inlet,

fixed elevation design with an estimated cost of $15,000,000. Sufficient concern was evidenced in

the review of the environmental assessment for unintended negative effects and the lack of a

detailed science plan to measure those effects that the environmental assessment was withdrawn

and not finalized.

A temperature control device workshop was convened in November 1999 to further develop

issues surrounding the device and to work on development of the science plan. One outcome of the

workshop was the discovery that native fish data had not been brought together and analyzed.

Opinions of native fish biologists on the status of endangered humpback chub differed sufficiently

to make obvious the need for the analysis. In response to this finding, GCMRC modified native fish

field contracts for year 2000 and reprogrammed funds into data compilation, analysis, and
January 2001 TCD Workshop March 13, 2001

Draft Summary of Findings Page 5

synthesis. This effort was complicated by the necessity of developing and carrying out the

monitoring and research conducted as part of the experimental native fish flows in year 2000. At

this time, GCMRC is in possession of all native fish data collected since 1990, and the analysis is

underway.

During year 2000, Reclamation resource managers discovered that projections for utilization of the

preferred alternative design for the temperature control device, previously estimated at 85 out of

100 years, were considerably overestimated and were closer to 45-50% of those years. This was

a result of misinterpretation of computer modeling outputs. The discovery has forced re-evaluation

of the engineering designs for the temperature control device.

Reclamation water quality modelers have undertaken analyses of release temperature deliveries

with different engineering designs and have discovered that modification of a subset of the 8 inlets

on Glen Canyon Dam may be sufficient to provide desired water temperatures.

Given these events and discoveries, it was decided to convene a second temperature control

device workshop including scientists and resource managers who could provide knowledgeable

input and recommendations on operation and assessment of effects to be integrated into the

research and monitoring plan and the forthcoming environmental assessment. Full results of the

recent TCD workshop, results of the GCMRC analysis, status of the development of the TCD

research and monitoring plan, analysis of engineering designs for the TCD, and evaluation of the

schedule for completion of the environmental assessment will be provided at the April 2001

AMWG meeting.