GCMRC Annual Reporting Meeting and 

Glen Canyon Dam Technical Work Group Meeting 

January 20-21, 2015 

Conducting: Vineetha Kartha, TWG Chair 

TWG Vice-Chair: Shane Capron 

Committee Members/Alternates Present: 

Jan Balsom, NPS/GRCA 

Cliff Barrett, UAMPS (phone) 

Charley Bulletts, So. Paiute Consortium 

Shane Capron, WAPA/TWG Co-Chair 

Kerry Christensen, Hualapai Tribe 

Jerry Lee Cox, Grand Canyon River Guides 

Kevin Dahl, National Parks Conservation Assn. 

Bill Davis, CREDA 

Kurt Dongoske, Pueblo of Zuni 

Evelyn Erlandsen, State of Arizona 

Paul Harms, State of New Mexico 

Committee Members Absent: 

Tony Joe, Jr., Navajo Nation 

Chip Lewis, Bureau of Indian Affairs 

Grand Canyon Monitoring and Research Center: 

Lucas Bair, Economist 

Joshua Caster 

Helen Fairley, Social Scientist 

Kyrie Fry, Communications Coordinator 

Paul Grams, Supervisory Hydrologist 

Ted Kennedy, Aquatic Biologist 

Dave Lytle, USGS-SBSC Director 

Jeff Muehlbauer, Research Biologist 

Erich Mueller, Research Hydrologist 

Interested Persons 

Mary Barger, Bureau of Reclamation 

Rob Billerback, NPS 

Peter Bungart, Hualapai Tribe 

Brian Collins, USGS (Menlo Park) 

Marianne Crawford, Bureau of Reclamation 

Jen Dierker, NPS 

Craig Ellsworth, WAPA (phone) 

Ed Gerak, CREDA 

Gerald Hooee, Sr., Pueblo of Z 

Leslie James, UAMPS/CREDA 

Sam Jansen, GCRG 

Lynn Jeka, WAPA 

Meeting Recorder: Linda Whetton 

Convened: 9:30 a.m. 

Chris Harris, State of California 

Robert King, State of Utah (phone) 

Glen Knowles, Bureau of Reclamation 

Ted Kowalski, Colo. Water Conservation Board 

Jerry Myers, Federation of Fly Fishers 

Don Ostler, representing Wyoming & New Mexico 

Larry Stevens, Grand Canyon Wildlands Council 

Bill Stewart, Arizona Game and Fish Dept. 

Jason Thiriot, State of Nevada 

Michael Yeatts, Hopi Tribe 

Kirk Young, FWS 

Robert King, State of Utah 

VACANT, State of Wyoming 

Emily Palmquist, 

Bill Persons, Fishery Biologist 

Joel Sankey, Research Geologist 

Daniel Sarr, 

Scott VanderKooi, Acting Center Director 

David Ward, Fishery Biologist 

Charles Yackulic, Research Statistician 

Mike Yard, Fishery Biologist 

John Jordan, Federation of Fly Fishers 

Matt Kaplinski, Northern Arizona University 

Joe Miller, Trout Unlimited 

Fred Nials, Desert Archaeology, Inc. 

Dr. Sarah Rinkevich, Joint Tribal Liaison 

Dave Rogwoski, AGFD 

Brian Sadler, WAPA 

Seth Shanahan, SNWA 

Rosemary Sucec, NPS/GCNRA 

Jerry Wilhite, WAPA 

Lisa Winters, AGFD 

Welcome and Administrative: Ms. Kartha welcomed the members and the public. Introductions were 

made and a quorum determined. 

GCDAMP T-shirts – Mr. Jason Thiriot. Members wanting to purchase a t-shirt with the GCDAMP logo 

need to submit their orders and money to Jason. The order will be placed on January 23, 2015. 

Geomorphology of the Active Channel and Valley Margins 
         

           

             

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Final Meeting Minutes – January 20‐21, 2015

Streamflow, Water Quality, and Sediment Transport in the Colorado River Ecosystem 

David J. Topping1

, Ronald E. Griffiths1, Nicholas Voichick1, Thomas A Sabol1, Nancy J. Hornewer2, Bradley D. 

Garner2

, and David J. Dean1 

1

U.S. Geological Survey, Grand Canyon Monitoring and Research Center 2

U.S. Geological Survey, Arizona Water Science Center 

The Streamflow, Water Quality, and Sediment Transport Core Monitoring Project is focused on high-resolution 

monitoring of stage, discharge, water temperature, specific conductance, dissolved oxygen, turbidity, and 

suspended-sediment concentration and particle size at a number of mainstem and tributary sites located 

throughout the Colorado River Ecosystem (CRE). These data are collected to address GCDAMP GOAL 7 and are 

used to inform managers on the physical status of the Colorado River in the CRE and how this physical status is 

affected by dam operations in near realtime. The high-resolution suspended-sediment data collected under this 

project are used to construct the mass-balance sediment budgets used by managers to trigger controlled floods 

under the 2012-2020 HFE protocol. 

During 2013-14, this project completed work on and delivered all data and publication products promised under the 

2013-14 Biennial Work Plan. The single most significant accomplishment during the period of the 2013-14 work 

plan was the completion of the new database and website. This website provides access to all of the current and 

legacy data collected by the Streamflow, Water Quality, and Sediment Transport Project and to all of the historical 

unit-value gage height and discharge data collected by the USGS at USGS gaging stations with QW and sediment 

data relevant to the CRE. The user-interactive tools available at this website to visualize and operate on the data 

are unique in the world. The two urls to use to access this new website are: 

http://www.gcmrc.gov/discharge_qw_sediment/ or http://cida.usgs.gov/gcmrc/discharge_qw_sediment/. 

Additional results will be made available on demand during the website demonstration at the poster session. 

Sandbars and Sediment Storage in Marble and Grand Canyons: Response to Recent High-flow 

Experiments and Long-term Trends 

Paul E. Grams, U.S. Geological Survey, Grand Canyon Monitoring and Research Center, Flagstaff, Arizona 

In October 2013, approximately 11 months after the 2012 high-flow experiment (HFE), the median size of sandbar 

monitoring sites in Marble Canyon had increased from the low point measured one year earlier. Topographic 

surveys and images from remote cameras indicate that the fall 2012 and 2013 HFEs resulted in increases in 

sandbar size in both Marble Canyon and Grand Canyon. These results indicate that the implementation of the HFE 

Protocol is causing increases in sandbar size. However, it is still too early in the Protocol implementation to 

determine whether the repeated HFEs are resulting in a cumulative increase in sandbar size. Analysis of remote 

sensing images for select reaches do not indicate a significant trend (increase or decrease) in sandbar area above 

the 8,000 ft3

/s elevation between May 2002 and May 2009. Analysis of these images together with images taken 

following the 1996 HFE indicate that sandbar area visible on these images is a function of the elapsed time 

between a HFE and image acquisition, supporting the hypothesis that sandbar area will increase, on average, with 

more frequent HFEs. 

Repeat mapping of the river channel has demonstrated that changes in sand storage are highly variable from one 

storage location (eddy) to the next. Repeat mapping of sandbars and the river channel in lower Marble Canyon 

(river mile (RM) 30 to 61) shows scour of the river bed and decreases in sandbar volume between May 2009 and 

May 2012. Most of this erosion occurred during the 2011 equalization flows and most of the sediment loss was from 

the river bed in the channel rather than from eddies or sandbars above the 8,000 ft3

/s stage. The magnitude of this 

sediment loss was less than the average annual input of sand from the Paria River. This suggests that, despite the 

large amount of sediment evacuation caused by equalization flows, most of the evacuated sediment likely 

consisted of recently accumulated Paria River sand inputs rather than older deposits of pre-dam sediment. Analysis 

of this repeat map that includes more than 80 large sandbars in this segment has also been used to evaluate the 

representativeness of the long-term monitoring sandbars. This analysis shows that the mean change in sandbar 

elevation at the long-term monitoring sandbars (the Northern Arizona University monitoring sites) in lower Marble 

Canyon was consistent with the mean response at all sandbars mapped in the 2009 and 2012 channel mapping 

efforts. 

Final Results of BWP Project J: Conditions and Processes Affecting Sand Resources at Archaeological 

Sites in the Colorado River Corridor Below Glen Canyon Dam 
         

           

             

 

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Joel B. Sankey, presenting for the Project J Staff [David Bedford, Josh Caster, Brian Collins, Skye Corbett, Amy 

East, Helen Fairley] 

Project J studied processes affecting archaeological sites in order to assess the likely effectiveness of HFEs to 

replenish sand supply to river-corridor sites, and to detect processes and rates of landscape change at selected 

sites. We determined that of the 358 river-corridor archaeological sites we evaluated, 266 (74%) have river-derived 

sand as a substrate, and that 232 (65%) have the potential to be affected by windblown sand from 45,000-cfs 

sandbars. We identified 31 sites that currently have the greatest potential to receive aeolian sand supply from HFE 

sandbars, because they have a direct upwind sand source and no vegetation or topographic barriers that could limit 

sand supply by wind. We determined that the proportion of sites affected by windblown sand from sandbars has 

varied over time. 40 years ago, there were 238 sites that had the potential to be affected by windblown sand, and 

98 sites were in the category with greatest potential to receive aeolian sand supply. 

We determined that gullies are less prevalent in sand areas that have active aeolian transport, whereas gullies 

occupy more of the sand area in places where the sand is inactive with respect to aeolian transport. Gully 

prevalence, and the proportion of active aeolian sand, vary substantially by reach, which is a function of canyon 

morphology, sand supply, and dominant wind direction. The reaches of the canyon that now have the greatest 

archaeological-site density (Glen Canyon, Furnace Flats, and Granite Park) are also those with the greatest gully 

prevalence, which are also the areas with the lowest proportions of active aeolian sand. Sand deposits in Glen 

Canyon are particularly gully-prone owing to canyon morphology, substantial bed incision, and very low modern 

sand supply. 

Archaeological sites that receive HFE sand supply can, even in a “best-case scenario”, still be affected by gully 

erosion on daily to seasonal time scales. Nonetheless, management actions that increase deposition of active 

aeolian sand area can reduce gully erosion, and HFEs can reduce gully extent in areas with upwind sandbars. 

Stakeholder Discussion: Management Implications of Geomorphology Monitoring and Research – Mr. Paul 

Grams. 

 If we can’t build bigger sand bars, can we build more sandbars? 

 Need for more cameras? Current preliminary reporting is from same set of sites. 

 Is there a larger model of wind direction and intensity possible in this system? 

 How do we balance preservation and excavation with other forms of destruction to archaeological sites? 

Cultural Resources 

Cultural Site Monitoring in Glen and Grand Canyons 

Brian Collins, U.S. Geological Survey, Menlo Park, California 

Cultural sites within the Colorado River corridor of Glen Canyon National Recreation Area and Grand Canyon 

National Park are subject to a suite of geomorphic processes that, in some cases, can threaten site integrity and 

stability. Using high-resolution lidar-derived topographic surveys and geomorphologic analyses of these survey 

data, we identify the magnitude and causes of changes at eight archaeological sites. We present change detection 

results for two recent time periods (2010-2013 and 2013-2014) in Grand Canyon and one time period (2012-2013) 

in Glen Canyon that bracket two recent high flow experiments (HFEs) from Glen Canyon Dam (November 2012 

and November 2013). These results indicate that precipitation-induced gullying erosion is prevalent in most cases, 

but that aeolian deposition can also occur and limit the magnitude of gullying. The source of aeolian sands at some 

sites appears to be from river-derived sand, indicating that gullying annealing processes can be directly related to 

fluvial processes of the Colorado River. 

Tourism’s Impact on Zuni Cultural Resources in Grand Canyon 

Gerald Hooee, Zuni AMWG Representative 

The Grand Canyon is a sacred place for the Zuni people. It is the location of the Zuni emergence into this present 

world, the place where sacred medicine bundles were created, and where the migrations of the Zuni medicine 

societies began. As part of the Glen Canyon Dam Adaptive Management Program, the Zuni religious leaders have 

been participating in annual river trips for the purpose of renewing their cultural and religious connections to the 

Grand Canyon and to monitor the health and condition of important Zuni places. In discussions with Zuni religious 
         

           

             

 

 

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leaders, the greatest impacts to places of Zuni importance in the Grand Canyon result from tourism. The various 

types of adverse impacts to Zuni traditional cultural properties that result from tourist activities in the Grand Canyon 

are presented. Mitigative activities that constructively control and/or modify tourist behavior are offered. 

Stakeholder Discussion: Management Implications of Cultural Monitoring and Research – Ms. Mary Barger. 

There is a lot of overlap in the program which is good in that encroachment limits people going into some 

archaeological sites. She continue to work with the tribes to see if there is a way to blend their work with what 

GCMRC is doing. 

	 The federal agencies have a responsibility to ensure that the identity of the tribes carries into the future and 

every facet of work being done should enable that. 

	 The biggest cultural disconnection is the “white” world sees the canyon as objective in trying to solve 

problems whereas the tribes talk about a living landscape and paying homage and respect by doing the 

right things. Having tribal presentations facilitates greater understanding. 

 Tribes need better understanding of what types of monitoring and reports are expected from them. 

 Need to know purpose for river trips.
 

Riparian Resources 

Developing Riparian Vegetation-Flow Response Guilds for the Colorado River Ecosystem in Grand Canyon, 

Arizona 

Daniel Sarr1

, David Merritt2, Emily Palmquist1, Julian Scott2, Patrick Shafroth3, and Barbara Ralston1 

US Geological Survey, Grand Canyon Monitoring and Research Center-SBSC, Flagstaff, AZ 86001 

U.S. Forest Service National Stream and Aquatic Ecology Center, USFS Watershed, Fish, Wildlife, Air and Rare 

Plants Staff, NRRC, 2150 Centre Ave., Bldg A, Suite 368, Fort Collins, CO 80526 

USGS Fort Collins Science Center, U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Ave., 

Bldg. C, Fort Collins, CO 80526 

River regulation in the semi-arid West has resulted in major changes to riparian communities and geomorphic 

patterns. To restore riparian vegetation communities and associated values, managers desire a better 

understanding of the linkages between flow variables and vegetation response. Riparian vegetation-flow response 

guilds provide a potential tool to mechanistically link flow attributes to the distribution and abundance of specific 

riparian vegetation groups. 

In this study, we compiled physiological and morphological trait information for 114 vascular plant species collected 

in 2012 and 2013 sampling along the Colorado River in Grand Canyon. For these species, we conducted two guild 

classifications using hierarchical cluster and analysis and Principal Coordinates Analysis ordination using eight trait 

variables. The first guild classification was an unsupervised classification that used a Gowers distance metric to 

classify the pool of 114 species into 7 groups. The second guild classification was supervised, and intentionally 

upweighted three traits (Anaerobic Tolerance, Drought Tolerance, and Height at Maturity) to ensure guilds were 

strongly linked to flow and were visually distinct. The supervised guild classification yielded 10 groups, from which 

we recognized 7 guilds with at least three species. 

For each guild classification, we constructed logistic regression models linking species probability of presence with 

flow exceedance (the proportion of time that a site was inundated during the period of detailed flow records from 

1985-2013). Logistic regression models were used to map the probability of occurrence on a large, heterogeneous 

sandbar, which showed a range of patterns from xeroriparian guilds on the highest microsites to hydroriparian 

guilds which occurred near the water’s edge or in lower side channels. We conclude that riparian vegetation flow 

response guilds present a new and valuable way of classifying vegetation into functional groups that may have 

direct application to riparian management and restoration. 

Southern Paiute Vegetation and Cultural Resource Monitoring Programs – Mr. Charley Bulletts. 

Stakeholder Discussion: Management Implications of Vegetation Monitoring and Research – Mr. Larry 

Stevens 

	 It appears we may be discounting changes that would’ve occurred naturally if there was no dam. 

	 There are historical photos showing where some plants haven’t changed. 
         

           

             

 

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Final Meeting Minutes – January 20‐21, 2015

 Silt is probably a strong driver for vegetation and may need some attention. 

Update on GCMRC Chief Position – Mr. Dave Lytle. The GCMRC Chief candidates’ public 

presentations will be held on January 28th (James “Dar” Crammond) and 29th (Joseph “Joe” SchubauerBerigan) in Flagstaff, Arizona. WebEx details will be provided at a later date. 

Public Comment: None 

Adjourned: 4:50 p.m. 
         

           

             

 

 

GCMRC Annual Reporting Meeting and

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GCMRC Annual Reporting Meeting and 

Glen Canyon Dam Technical Work Group Meeting 

January 20-21, 2015 

Page 6

Conducting: Vineetha Kartha, TWG Chair 

Committee Members/Alternates Present: 

Jan Balsom, NPS/GRCA 

Cliff Barrett, UAMPS (phone) 

Charley Bulletts, So. Paiute Consortium 

Shane Capron, WAPA/TWG Co-Chair 

Kerry Christensen, Hualapai Tribe 

Jerry Lee Cox, Grand Canyon River Guides 

Kevin Dahl, National Parks Conservation Assn. 

Bill Davis, CREDA 

Kurt Dongoske, Pueblo of Zuni 

Evelyn Erlandsen, State of Arizona 

Paul Harms, State of New Mexico 

Committee Members Absent: 

Tony Joe, Jr., Navajo Nation 

Chip Lewis, Bureau of Indian Affairs 

Grand Canyon Monitoring and Research Center: 

Lucas Bair, Economist 

Joshua Caster 

Helen Fairley, Social Scientist 

Kyrie Fry, Communications Coordinator 

Paul Grams, Supervisory Hydrologist 

Ted Kennedy, Aquatic Biologist 

Dave Lytle, USGS 

Ted Melis, Physical Scientist 

Jeff Muehlbauer, Research Biologist 

Interested Persons 

Mary Barger, Bureau of Reclamation 

Rob Billerback, NPS 

Peter Bungart, Hualapai Tribe 

Brian Collins, USGS (Menlo Park) 

Marianne Crawford, Bureau of Reclamation 

Jen Dierker, NPS 

Craig Ellsworth, WAPA (phone) 

Ed Gerak, CREDA 

Gerald Hooee, Sr., Pueblo of Z 

Leslie James, UAMPS/CREDA 

Sam Jansen, GCRG 

Lynn Jeka, WAPA 

Meeting Recorder: Linda Whetton 

Convened: 8:10 a.m. 

Chris Harris, State of California 

Robert King, State of Utah (phone) 

Glen Knowles, Bureau of Reclamation 

Ted Kowalski, Colo. Water Conservation Board 

Jerry Myers, Federation of Fly Fishers 

Don Ostler, representing Wyoming & New Mexico 

Larry Stevens, Grand Canyon Wildlands Council 

Bill Stewart, Arizona Game and Fish Dept. 

Jason Thiriot, State of Nevada 

Michael Yeatts, Hopi Tribe 

Kirk Young, FWS 

Robert King, State of Utah 

VACANT, State of Wyoming 

Erich Mueller, Research Hydrologist 

Emily Palmquist, 

Bill Persons, Fishery Biologist 

Joel Sankey, Research Geologist 

Daniel Sarr, 

Scott VanderKooi, Acting Center Director 

David Ward, Fishery Biologist 

Charles Yackulic, Research Statistician 

Mike Yard, Fishery Biologist 

John Jordan, Federation of Fly Fishers 

Matt Kaplinski, Northern Arizona University 

Joe Miller, Trout Unlimited 

Fred Nials, Desert Archaeology, Inc. 

Dr. Sarah Rinkevich, Joint Tribal Liaison 

Dave Rogwoski, AGFD 

Brian Sadler, WAPA 

Seth Shanahan, SNWA 

Rosemary Sucec, NPS/GCNRA 

Jerry Wilhite, WAPA 

Lisa Winters, AGFD 

Welcome and Administrative: Ms. Kartha welcomed the members and the public. Introductions were 

made. 

Management Actions, Experiments, and Related Research 

Endangered Humpback Chub Translocations to Colorado River Tributaries in Grand Canyon National Park 
         

           

             

 

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Final Meeting Minutes – January 20‐21, 2015

Omana Smith, Emily C.1, Brian D. Healy1, Clay Nelson1, Melissa Trammell2, Shannon Blackburn1 

1

National Park Service, Grand Canyon National Park, 1824 South Thompson Street, Suite 200, Flagstaff, Arizona 

2

National Park Service, Intermountain Region, 324 S. State St. Suite 200, Salt Lake City, UT 84111 

Historic fish communities in Grand Canyon National Park consisted of eight species, six of which are endemic to 

the Colorado River Basin. Today, reproducing and recruiting populations of only four native species are known to 

occur in the Park, including Humpback Chub, Gila cypha, which is listed under the Endangered Species Act. The 

Colorado River in Grand Canyon contains the largest remaining population of Humpback Chub, one that faces 

significant threats, including the presence of nonnative fish and parasites, and altered temperature and flow 

regimes. Additionally, the Grand Canyon population primarily spawns in one location, the Little Colorado River, 

which is threatened by watershed-wide impacts. In accordance with the Comprehensive Fisheries Management 

Plan for Grand and Glen canyons (NPS 2013), Grand Canyon National Park, with the assistance of the Bureau of 

Reclamation and others, initiated a series of Humpback Chub translocations in Havasu and Shinumo creeks to 

contribute towards the long-term goals of establishing additional spawning aggregations and/or increasing 

mainstem aggregations of the Humpback Chub within the park. Apparent annual survival rates are presented for 

translocated fish in Shinumo and Havasu creeks, along with contribution to mainstem Humpback Chub, growth, 

and evidence for spawning. Additionally, flood and fire impacts to the Shinumo Creek fish community following the 

2014 managed Galahad Fire are presented. 

Bright Angel Creek Trout Reduction Project 

Clay Nelson, Brian Healy, Emily Omana Smith, Shannon Blackburn 

NPS - Grand Canyon National Park 

David Ward, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and 

Research Center, Flagstaff, Arizona 

The Bright Angel Creek Trout Reduction Project is an NPS-led interagency cooperative effort with the USGS, and 

funded by the Bureau of Reclamation to enhance native fish populations and contribute towards the fulfillment of 

Humpback Chub (Gila cypha) conservation measures for the operation of Glen Canyon Dam. The results of this 

adaptive management project will be measured against objectives included in the NPS Comprehensive Fisheries 

Management Plan, following implementation of 5 consecutive years (2012-2017) of nonnative trout control in and 

around Bright Angel Creek. Trout reduction efforts consist of the installation and operation of a weir to trap and 

remove spawning trout in the mouth of Bright Angel Creek, backpack electrofishing depletion sampling in Bright 

Angel Creek (approx. 10 miles), and boat mounted electrofishing depletion sampling in the Bright Angel Creek 

Inflow. The third year of reduction efforts is currently underway, and will conclude in March 2015. Preliminary 

results indicate that weir captures have varied from year to year, and reduction efforts in the creek have yielded 

12,456 and 10,545 Brown Trout (Salmo trutta) and 1,735 and 1,400 Rainbow Trout (Oncorhynchus mykiss) in 

2012-2013 and 2013-2014, respectively. A Bright Angel Creek Inflow depletion sampling feasibility study occurred 

in November-December of 2013-2014. While catches were limited due to turbid water, a depletion was still 

achieved with a total of 332 Brown Trout and 1,375 Rainbow trout removed. Population estimates, length frequency 

data, and native fish survival analyses will be used to evaluate the effectiveness of the project. All nonnative fish 

removed during the project have been put to beneficial use, consistent with a Memorandum of Agreement with the 

State Historic Preservation Office, following NHPA Section 106 consultation with Traditionally Associated tribes. 

Native-Nonnative Interactions; Factors Influencing Predation Vulnerability 

David Ward, Rylan Morton-Starner, and Ben Vaage, U.S. Geological Survey, Southwest Biological Science Center, 

Grand Canyon Monitoring and Research Center, Flagstaff, Arizona 

Predation on juvenile native fish by introduced rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) 

is considered a significant threat to the persistence of endangered humpback chub (Gila cypha) in the Colorado 

River. Diet studies of rainbow trout and brown trout in Grand Canyon indicate that these species do eat native fish, 

but population level impacts are difficult to assess because predation vulnerability is highly variable depending on 

the sizes of the prey and predators and the water temperature and turbidity under which the predation interactions 

take place. We conducted laboratory experiments to evaluate how short-term predation vulnerability of juvenile 

native fish changes in response to fish size, water temperature and turbidity using captive reared humpback chub, 

bonytail (Gila elegans), and roundtail chub (Gila robusta). Juvenile chub 45 to 90 mm total length (TL) were 

exposed to adult rainbow and brown trout at 10, 15, and 20 °C and at turbidities ranging from 0 to 150 formazin 

nephlometric units (FNU). A 1°C increase in water temperature decreased short term predation vulnerability of 

humpback chub to rainbow trout by about 5% although the relationship was is not linear. Our results indicate that 
         

           

             

 

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turbidity as low as 50 FNU can reduced predation vulnerability of bonytail to rainbow trout by 63% (95% confidence 

interval = 43% - 82%). Of the factors we tested, chub size and turbidity had the largest effect on predation 

vulnerability to rainbow trout. Brown trout were highly piscivorous at any size >220 mm TL and at all of the water 

temperatures and turbidities tested. Understanding the effects of predation by trout on endangered humpback 

chub is critical in evaluating management options aimed at preservation of native fishes in Grand Canyon. We 

present a modeling tool, based on laboratory data, which can assist managers in evaluating these management 

options. 

Aquatic Ecology and Fishes in Marble and Grand Canyons 

Aquatic foodbase in Glen, Marble, and Grand Canyon 

Ted Kennedy, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and 

Research Center, Flagstaff, Arizona 

Foodweb studies conducted from 2006-2009 demonstrated that algae is the base of the foodweb in Glen, Marble, 

and Grand Canyon, and native and desired non-native fish are limited by the availability of high quality insect prey 

(i.e., midges and blackflies). Based on these insights, long-term monitoring of key foodbase components was 

implemented in 2007 (invertebrate drift in Glen Canyon), 2009 (algae production in Glen, Marble, and Grand 

Canyon), and 2012 (insect emergence in Marble and Grand Canyon). In this presentation I will show recent 

analyses from long-term drift and algae production monitoring programs. Analysis of algae production data from 

Marble and Grand Canyon (2009-2011) demonstrates that turbidity, light, temperature and hydropeaking control 

rates of algae production, with turbidity and light being most important. Long-term drift monitoring in Glen Canyon 

(2007-2013) indicates drift abundance of key prey items (midges and blackflies) was low in 2007 and increased 

dramatically in 2008 due to the March HFE. However, drift abundance of these species has declined from 2008­

2013. In contrast, drift of New Zealand mudsnails, tubificid worms, and Gammarus was high in 2007 and declined 

precipitously in 2008 because of the HFE, but drift of these three species has increased from 2008 through 2013. 

Thus, the November 2012 HFE did not restructure Glen Canyon invertebrate assemblages in the same way that 

the March 2008 HFE did. Specifically, midge and blackfly drift in 2013 was low and similar to prior years, while drift 

of mudsnails, worms, and Gammarus remained high in 2013 and was similar to prior years. 

Rainbow trout movement, recruitment, population dynamics and modeling in Marble Canyon 

Josh Korman, Ecometric Research Inc., 3560 W 22nd Ave, Vancouver, BC, Canada 

Michael D. Yard, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and 

Research Center, Flagstaff, Arizona 

We conducted an intensive mark-recapture study of rainbow trout (Oncorhynchus mykiss) downstream of Glen 

Canyon Dam to better understand what controls their abundance in areas used by endangered native fish. In this 

study, we describe seasonal and spatial variation in abundance, movement and condition of rainbow trout in the 

Colorado River downstream of Glen Canyon Dam, and use this information to better understand factors that could 

be influencing their population dynamics. Over a 3-year period, we PIT-tagged more than 80,000 trout in the130 

km-long study area, and recovered over 9,213 tagged fish. There was a rapid decline in trout abundance with 

increasing distance from Glen Canyon Dam, with densities ranging from 10,000-25,000 fish/km near the dam to 

200-800 fish/km 125 km downstream, near the Little Colorado River (LCR) where native fish rear. Trout populations 

in upstream reaches declined over the study period, while the population grew in reaches near the LCR. The extent 

of rainbow trout movement was limited, with less than 1% of over 8,000 recaptures making movements greater 

than 20 km. Although, there is local reproduction in middle and lower Marble Canyon that is variable across years 

the small the proportion of fish emigrating from upstream reaches that move downstream are sufficient to explain 

the increasing trend in abundance at the LCR. 

Movement of trout from Lees Ferry to Marble Canyon can be episodic, and recaptures show that both small (age-0) 

and large (older) trout can move from Lees Ferry to Marble Canyon. These movements may be driven by density 

dependent factors and poor condition. Reducing the magnitude and frequency of large annual cohorts in Lees Ferry 

(e.g., 2011super-cohort) may be best way to reduce trout emigration to Marble Canyon. This may also help 

maintain the quality of fishery in Lees Ferry and avoid the cyclical patterns in abundance and condition previously 

observed. 
         

           

             

 

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Colorado River fish monitoring in Grand Canyon, Arizona: 1990-2014 humpback chub, Gila cypha, 

aggregations 

William R. Persons, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and 

Research Center, Flagstaff, Arizona 

David R. VanHaverbeke, U.S. Fish and Wildlife Service 

Michael Dodrill, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and 

Research Center, Flagstaff, Arizona 

Brian Healey, Grand Canyon National Park 

Humpback chub, Gila cypha, is an endangered cyprinid species endemic to the Colorado River basin of the 

western United States. The species was described in 1946 by R. Miller from a specimen taken near the mouth of 

Bright Angel Creek, Grand Canyon National Park, Arizona; and was listed as endangered in 1967. Long term fish 

monitoring in the Colorado River downstream of Glen Canyon Dam is a component of the Glen Canyon Dam 

Adaptive Management Program. Monitoring for humpback chub in the mainstem Colorado River in Grand Canyon 

has been conducted sporadically since the 1970’s, and has improved since the introduction of small motorized 

watercraft and the use of hoopnets and trammel nets. Mainstem netting has occurred in three time periods: period 

1 (1991–1993), period 2 (2002–2006), and period 3 (2010-2013). Nine humpback chub aggregations were 

originally identified based on fish collected during 1990-1993, and closed population model abundance estimates 

were generated for six of those aggregations. An aggregation was defined as “a consistent and disjunct group of 

fish with no significant exchange of individuals with other aggregations, as indicated by recapture of PIT-tagged 

juveniles and adults and movement of radio-tagged adults”. We redefined aggregations and their boundaries based 

on current catch and PIT tag recapture information. Efforts to estimate abundance of mainstem humpback chub 

using pooled capture probabilities and catch rates were unsuccessful due to model assumption violations and 

relatively low recapture rates. Instead, we fit generalized linear models with a negative binomial error distribution to 

model adult (> 200 mm total length) humpback chub catch (counts) and included the log of effort (hours) as an 

offset to account for varying levels of effort. We found support for the hypothesis that adult humpback chub catch 

varies by time period, river location, and that the catch of fish within the LCR inflow aggregation varies between 

time periods compared to other mainstem locations. Models that included a term specifying whether a location is 

an aggregation or non-aggregation were not as highly supported. Fish that have been translocated to Shinumo and 

Havasu Creeks were generally recaptured in river sections close to the tributaries, and hoop net catch was higher 

when including translocated fish. 

Humpback Chub (Gila Cypha) Population Dynamics and Modeling: Juveniles, Sub-adults, and Adults in the 

Colorado and Little Colorado Rivers 

Charles Yackulic and Maria Dzul, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon 

Monitoring and Research Center, Flagstaff, Arizona 

Since 2009, GCMRC biologists and their collaborators have regularly sampled a fixed reference reach in the 

Colorado River just below its confluence with the Little Colorado River as a part of monitoring the status of 

humpback chub (Gila cypha). Mark-recapture data from this reach have dramatically improved our understanding of 

humpback chub survival and growth in the mainstem Colorado River, particularly with respect to juvenile fish. When 

these data are analyzed together with longterm system wide sampling in the Little Colorado River led by USFWS, a 

holistic understanding of humpback chub population dynamics emerges. Recent data suggests a stable adult 

population, however, because of long time lags this stability could be misleading. Understanding juvenile 

recruitment, outmigration, and survival provides a leading indicator of future change. Many factors likely contribute 

to variation in juvenile survival including the size of juveniles and the abundance of rainbow trout. Growth allows 

chub to quickly move through vulnerable life stages and appears to be strongly driven by water temperature. The 

size structure of juveniles in the mainstem is affected by preceding conditions in the LCR as the amount of 

outmigrants and their size structure can vary annually. Turbidity also likes play a role in both juvenile survival and 

growth. 

Biological Opinion Trigger Update 

Scott VanderKooi, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and 

Research Center, Flagstaff, Arizona 

The Bureau of Reclamation received a biological opinion on the operation of Glen Canyon Dam from the U.S. Fish 

and Wildlife Service in December of 2011. This presentation will review the biological and physical triggers for 
         

           

             

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nonnative fish control implementation. A review of current population estimates for humpback chub (Gila cypha) 

and rainbow trout (Oncorhynchus mykiss), survival estimates for juvenile humpback chub, and Colorado River 

mainstem temperatures recorded in 2014 will also be provided. Results from 2014 indicate that the suite of triggers 

required to implement nonnative fish control have not been met. To date only one criterion, rainbow trout 

abundance just downstream of the Little Colorado River confluence, has exceeded trigger levels identified in the 

2011 biological opinion. 

Stakeholder Discussion: Management Implications of Aquatic Ecology and Native and Nonnative Fish 

Monitoring and Research ̶ Mr. Kirk Young. 

 Translocation is a tool that can be used to jumpstart fish, increase growth. 

 Different effects and what’s driving survival – looking at size of prey. 

 Looking at what a spring flow might do in terms of food is another management tool. 

 Josh Korman’s work on trout and what’s driving food and movement is another opportunity to integrate 

information. 

 It would be interesting to clarify that HBC are reproducing in springs-related areas. 

 Per Wendell Minckley’s report on abundant HBC at the Paria River. That is a “ghost” aggregation and it 

needs to be recognized. 

 What happens if LCR is wiped out? How does the population respond? That’s missing from recovery goals. 

 A critical gap in knowledge is the issue of imprinting. 

 The Pueblo of Zuni may not have known about mechanical removal occurring at Ribbon Falls. 

Aquatic Ecology of Glen Canyon and the Lees Ferry Fishery 

Physical Environment of the Glen Canyon Dam Rainbow Trout Fishery 

T.S. Melis, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research 

Center, Flagstaff, Arizona 

Rainbow trout responses to Glen Canyon Dam operations are complex and generally known to vary relative to 

physical and biological processes. Flows and quality-of-water monitoring, such as water temperature, dissolved 

oxygen and turbidity, typically supports fishery studies. Increased trout recruitment in Glen Canyon has occurred in 

at least 5 of 18 years (28%) since Glen Canyon Dam was re-operated to Modified Low Fluctuating Flows (MLFF) in 

fall 1996 (1997, 2000, 2008-9 and 2011). Recent modelling research identified dam releases in 1997, 2000 and 

2008, as key to explaining the two-fold increases in trout recruitment between 1990 and 2010, and monitoring also 

showed elevated recruitment in 2009 and 2011. In 4 of the years, high-flow dam releases occurred in spring, and 

annual dam release volumes were above the minimum required to meet downstream water deliveries. All 5 years 

had steadier flows in either spring/summer, and (or) fall, and included experimental flows in addition to MLFF. River 

bed characteristics, consisting of highly varied sediments that are substrates for invertebrates, vegetation, are also 

commonly considered in trout studies. Sediment inputs from tributaries to the Colorado River can alter channel 

geometry and bed texture in ways that might influence aquatic resources, but bed evolution has not been part of 

past fishery studies. In Glen Canyon, there are 32 ephemeral tributaries that drain 291 square kilometers (km2

). 

During summer 2013, at least two floods from Waterholes Canyon delivered new sediment to the Colorado River, 

altering its bed in lower Glen Canyon. MLFF dam releases and 3 fall-timed high flow experiments have since 

winnowed and transported the finer fraction of the deposits downstream, revealing new gravel bars. Analyses of 

bed-texture imagery, aquatic vegetation, foodbase, and water quality data collected in coordination with Natal 

Origins of Rainbow Trout project monitoring in Glen Canyon are being integrated to determine how tributary and 

main channel sediment-transport processes may influence the recreational tailwater fishery. 

Quagga Mussel Risk Assessment 

Ted Kennedy, U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and 

Research Center, Flagstaff, Arizona 

Quagga mussels (Dreissena bugensis) became established in Lake Powell and the Glen Canyon segment of the 

Colorado River in spring/summer of 2014. In this presentation, I describe 1) potential risks of quagga mussels 

establishing at high densities in the Colorado River ecosystem (CRE) and 2) the risk of ecological impacts should 

quagga establish at high densities in the CRE. 
         

           

             

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The risk of quagga establishing within the CRE appears low, except for the Glen Canyon tailwater reach where the 

risk appears high. Quagga are unlikely to establish at high densities within the CRE because of high suspended 

sediment, high ratios of suspended inorganic: organic material, and high water velocities, all of which interfere with 

the ability of quagga to effectively filter feed. Additionally, high turbulence in the rapids of Grand Canyon may 

represent a large source of mortality to larval quagga mussels, which would limit their ability to disperse and 

colonize downstream reaches of the CRE. In contrast, conditions within the Lees Ferry tailwater appear suitable for 

quagga establishment, and recent surveys indicate this has already occurred. 

If quagga mussels establish within the CRE, the risks of negative ecological impacts appear low. If quagga mussels 

are able to attain moderate densities in Lees Ferry, estimates of filtration capacity indicate they are unlikely to 

substantially alter the composition (e.g., nutrient concentrations, suspended organic matter concentrations) of water 

exported from Lees Ferry. Further, a moderate density of Dreissena within Lees Ferry may actually increase food 

available to fishes by increasing habitat complexity and stimulating benthic production. If quagga attain moderate 

densities in the CRE mainstem, which seems unlikely, ecological impacts will probably be comparable to Lees 

Ferry—an increase in benthic production. Quagga mussels may also have ecological impacts on the CRE, if they 

substantially alter the composition of water released from Glen Canyon Dam; however, it is unclear whether 

changes in the composition of water released from Glen Canyon Dam (i.e., lower phytoplankton abundance and 

higher dissolved nutrients) will have a net positive or negative impact on food availability in the CRE mainstem. 

Rainbow Trout Growth, Condition, Population Dynamics and Modeling in Glen Canyon 

Michael D. Yard, U.S. Geological Survey, Grand Canyon Monitoring and Research Center, Flagstaff, AZ 

Josh Korman, Ecometric Research Inc., 3560 W 22nd Ave, Vancouver, BC, Canada 

The Lees Ferry model uses a standard Cormack-Jolly-Seber approach to estimate survival rate and capture 

probability of marked rainbow trout (Oncorhynchus mykiss), based on the known number of marks released and 

recaptures on latter trips. Estimates of across-trip capture probability are enhanced by within-trip recaptures and 

the assumed relationship between across-trip and within-trip capture probabilities (i.e., robust design approach). 

The unmarked catch on any trip can be expanded by the across-trip capture probability to estimate a size-stratified 

abundance of the unmarked population. Preliminary analyses indicate that trout abundance has declined over a 2.5 

year period by 83% from 1,200,000 to 200,000 fish. There is considerable heterogeneity in capture probabilities 

influenced by fish size, density, and season, which affects the interpretation of monitoring indices for relative 

abundance and size-structured catch proportions. Decreased growth and survival of large fish, particularly in 2014, 

indicate that smaller fish are disproportionately acquiring or not expending energy relative to larger fish. Following 

the 2011 super-cohort, reduced recruitment of age-0 fish and their subsequent low survival has been insufficient to 

sustain population levels. Size-stratified condition factors for trout are highly variable across size classes, among 

and within years, and throughout sampling sites. There is a longitudinal downstream trend of decreasing fish 

condition in Glen Canyon. Although there are numerous factors (prey availability, diversity, and size; high flow 

experiments and water quality) that are potential mechanisms, the most likely proximal factor in the decline of trout 

is excessive trout recruitment in 2011, and perhaps earlier in 2008 that has been linked to higher and steadier dam 

operations, and has negatively influenced the carrying capacity of Glen Canyon, through a top down effect. 

Implementing novel measures that prescriptively control for excess recruitment through trout management flows 

and managed harvesting are two options that can be explored as management strategies. 

Annual Reporting 2015 – Bioenergetics Modeling 

Mike Dodrill, U.S. Geological Survey, Grand Canyon Monitoring and Research Center, Flagstaff, Arizona 

Charles B. Yackulic, U.S. Geological Survey, Grand Canyon Monitoring and Research Center, Flagstaff, Arizona 

Ted Kennedy, U.S. Geological Survey, Grand Canyon Monitoring and Research Center, Flagstaff, Arizona 

The Lees Ferry tailwater supports a recreational fishery in which the maximum size of adult rainbow trout 

(Oncorhynchus mykiss) has declined through time. Field, laboratory, and modeling studies have demonstrated that 

water temperature, prey availability (concentration of drifting invertebrates), and the size distribution of prey often 

interact to influence growth of drift-feeding fish. We developed a drift foraging and bioenergetics model to identify 

which of these factors limit rainbow trout growth in the Colorado River downstream of Glen Canyon Dam. Model 

predictions were first validated by comparing predicted growth with empirical growth estimates from the natal 

origins project. We then explored the importance of temperature, prey quantity, and prey size by comparing 

predicted growth under the current biological (drift) and physical (temperature) conditions with scenarios 

representing altered conditions. Our results demonstrate that rainbow trout growth in Lees Ferry is limited by the 
         

           

             

 

 

 

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scarcity of large prey items and overall prey availability. Additionally, warmer temperatures (2005) always resulted 

in lower growth compared to cooler temperatures (2002), even when prey availability was simultaneously 

increased. These results provide additional evidence that rainbow trout growth is food limited, and the effect of 

food limitation is exacerbated when water temperatures are warm. 

Lees Ferry Fishery Monitoring: Electrofishing Surveys, Angler Surveys, and Spawning and Rearing 

Surveys 

David L. Rogowski and Lisa K. Winters, Arizona Game and Fish Department, Flagstaff, Arizona 

Glen Canyon Dam on the Colorado River, Arizona was completed in 1963. The resulting cold water releases 

created a popular rainbow trout tailwater fishery known for trophy size rainbow trout. Arizona Game and Fish 

Department has been monitoring the Lees Ferry fishery since the early 1980s using angler (creel) surveys and boat 

electrofishing. Dam operations have had a significant effect on the rainbow trout population. Flow from the dam was 

regulated in response to power demands with water levels fluctuating up to 15 feet daily, until 1996 when modified 

low fluctuating flows (MLFF) were implemented, significantly reducing variance in flows. Prior to the MLFF the 

rainbow trout fishery was maintained via stocking. However, stocking ceased in 1998 when the majority of rainbow 

trout were maintained via natural production. Since 1981 the median size of reproductively mature rainbow trout 

has declined as well as the percent of large fish (>456 mm; 18 inches) in the population. Consistent flow levels 

have allowed rainbow trout to naturally reproduce every year, thereby increasing density and competition for a 

limited food base. Rainbow trout populations have been somewhat cyclical with a recent record peak in catch per 

unit effort in 2011-2012, after record young of the year production from 2008-2011; catch per unit effort 

(electrofishing) has since declined. Currently (Fall 2014) rainbow trout condition is at the lowest level since 

standardized monitoring began 24 years ago. Current conditions favor fish that mature and reproduce early, 

resulting in smaller fish, a concern for the status of this important blue ribbon fishery. While managers have trigger 

points for action when there are too few rainbow trout (minimum catch rates, percent young of the year), these 

metrics are lacking for when there are too many fish. Future management goals are to reduce these extremes in 

recruitment and fish condition. 

Stakeholder Discussion: Management Implications of Applied Research and Recent Findings in Lees Ferry

and Glen Canyon – Mr. Bill Stewart. 

Public Comment: Mr. Joe Miller (Trout Unlimited) – The Sixth Annual Native and Wild Trout Conference is 

scheduled for April 23, 2015, at Arizona Game and Fish Headquarters. For more information: http://aztu.org/2015/sixth-annual-native-and-wild-trout-conference-scheduled-april-23-2015. 

Adjourned: 5 p.m. 

Upcoming Meetings: 

 May 28, 2015 AMWG Meeting via webinar 

 (W-Th) June 10-11, 2015 TWG Meeting at ADWR or June 10 via webinar 

 (late) August 19-20, 2015 AMWG Meeting in Flagstaff (location TBD) 

Respectfully submitted, 

Linda Whetton 

Bureau of Reclamation 

Upper Colorado Region 
         

           

             

 

 

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Key to Glen Canyon Dam Adaptive Management Program Acronyms 

ADWR – Arizona Dept. of Water Resources 

AF – Acre Feet 

AGFD – Arizona Game and Fish Department 

AIF – Agenda Information Form 

AMP – Adaptive Management Program 

AMWG – Adaptive Management Work Group 

AOP – Annual Operating Plan 

ASMR – Age-Structure Mark Recapture 

BA – Biological Assessment 

BAHG – Budget Ad Hoc Group 

BCOM – Biological Conservation Measure 

BE – Biological Evaluation 

BHBF – Beach/Habitat-Building Flow 

BHMF – Beach/Habitat Maintenance Flow 

BHTF – Beach/Habitat Test Flow 

BIA – Bureau of Indian Affairs 

BO – Biological Opinion 

BOR – Bureau of Reclamation 

BWP – Budget and Work Plan 

CAHG – Charter Ad Hoc Group 

CAP – Central Arizona Project 

GCT – Grand Canyon Trust 

CESU – Cooperative Ecosystems Studies Unit 

cfs – cubic feet per second 

CFMP – Comprehensive Fisheries Management Plan 

CMINS – Core Monitoring Information Needs 

CMP – Core Monitoring Plan 

CPI – Consumer Price Index 

CRBC – Colorado River Board of California 

CRAHG – Cultural Resources Ad Hoc Group 

CRCN – Colorado River Commission of Nevada 

CRE – Colorado River Ecosystem 

CREDA – Colorado River Energy Distributors Assn. 

CRSP – Colorado River Storage Project 

CWCB – Colorado Water Conservation Board 

DAHG – Desired Future Conditions Ad Hoc Group 

DASA – Data Acquisition, Storage, and Analysis 

DBMS – Data Base Management System 

DOE – Department of Energy 

DOI – Department of the Interior 

DOIFF – Department of the Interior Federal Family 

EA – Environmental Assessment 

EIS – Environmental Impact Statement 

ESA – Endangered Species Act 

FACA – Federal Advisory Committee Act 

FEIS – Final Environmental Impact Statement 

FRN – Federal Register Notice 

FWS – United States Fish & Wildlife Service 

FY – Fiscal Year (October 1 – September 30) 

GCD – Glen Canyon Dam 

GCES – Glen Canyon Environmental Studies 

GCT – Grand Canyon Trust 

GCMRC – Grand Canyon Monitoring & Research Center 

GCNP – Grand Canyon National Park 

GCNRA – Glen Canyon Nat’l Recreation Area 

GCPA – Grand Canyon Protection Act 

GLCA – Glen Canyon Nat’l Recreation Area 

GRCA – Grand Canyon National Park 

GCRG – Grand Canyon River Guides 

GCWC – Grand Canyon Wildlands Council 

HBC – Humpback Chub (endangered native fish) 

HFE – High Flow Experiment 

HMF – Habitat Maintenance Flow 

HPP – Historic Preservation Plan 

IG – Interim Guidelines 

INs – Information Needs 

KA – Knowledge Assessment (workshop) 

KAS – Kanab Ambersnail (endangered native snail) 

LCR – Little Colorado River 

LCRMCP – Lower Colorado River Multi-Species 

Conservation

 Program 

LTEMP – Long-Term Experimental and Management Plan 

LTEP – Long Term Experimental Plan 

MAF – Million Acre Feet 

MA – Management Action 

MATA – Multi-Attribute Trade-Off Analysis 

MLFF – Modified Low Fluctuating Flow 

MO – Management Objective 

MRP – Monitoring and Research Plan 

NAU – Northern Arizona University (Flagstaff, AZ) 

NEPA – National Environmental Policy Act 

NHPA – National Historic Preservation Act 

NNFC – Non-native Fish Control 

NOI – Notice of Intent 

NPCA – National Parks Conservation Association 

NPS – National Park Service 

NRC – National Research Council 

O&M – Operations & Maintenance (USBR Funding) 

PA – Programmatic Agreement 

PBR – Paria to Badger Creek Reach 

PEP – Protocol Evaluation Panel 

POAHG – Public Outreach Ad Hoc Group 

Powerplant Capacity = 31,000 cfs 

R&D – Research and Development 

RBT – Rainbow Trout 

RFP – Request for Proposal 

RINs – Research Information Needs 

ROD Flows – Record of Decision Flows 

RPA – Reasonable and Prudent Alternative 

SA – Science Advisors 

Secretary – Secretary of the Interior 

SCORE – State of the Colorado River Ecosystem 

SHPO – State Historic Preservation Office 

SOW – Statement of Work 

SPAHG – Strategic Plan Ad Hoc Group 

SPG – Science Planning Group 

SSQs – Strategic Science Questions 

SWCA – Steven W. Carothers Associates 

TCD – Temperature Control Device 

TCP – Traditional Cultural Property 

TEK – Traditional Ecological Knowledge 

TES – Threatened and Endangered Species 

TMC – Taxa of Management Concern 

TWG – Technical Work Group 

UCRC – Upper Colorado River Commission 

UDWR – Utah Division of Water Resources 

USBR – United States Bureau of Reclamation 

USFWS – United States Fish & Wildlife Service 

USGS – United States Geological Survey 

WAPA – Western Area Power Administration 

WY – Water Year 

(Updated: 2/20/2014)