Technical Work Group

April 22, 2015

Phoenix AZ
 These recommendations were developed collaboratively 

among recreational anglers, including: 

 Arizona Trout Unlimited; 

 Arizona Sportsmen for Wildlife Conservation; 

 Arizona Flycasting Club 

 Anglers United 

 International Federation of Fly Fishers; 

 Northern Arizona Flycasters

 Theodore Roosevelt Conservation Partnership. 

 In consultation with the Arizona Game and Fish 

Department, the U.S. Geological Survey Grand Canyon 

Monitoring and Research Center, and Lees Ferry guides.
Glen Canyon Recreation Area Desired Conditions

 Opportunities for anglers to have a memorable 

experience.

 Habitat that supports a rainbow trout population with a 

size structure indicative of a stable population.

GCD AMP Desired Future Conditions 

 Establish a high-quality sustainable recreational trout fishery in the 

river corridor in GCNRA, while minimizing emigration of non-native 

fishes.

 Operate Glen Canyon Dam (GCD) to achieve the greatest benefit to 

the trout fishery in GCNRA without causing excessive detriment to 

other resources.


Goal 1. Maintain and enhance a wild (self-sustaining) Blue 

Ribbon rainbow trout fishery consistent with the protection 

and recovery of the native aquatic community in Grand 

Canyon National Park.

 Stable RBT population (e.g., on an annual basis, 20-80% of the 

RBT population will be less than 6 inches).

 Maintain angler catch rates of at least 10 fish/day >14 inches w/ 

catch rate greater than 1 fish/hr

 Provide an angler catch rate of at least 1 fish/day >20 inches 

Goal 2. Provide a dependable, high-quality recreational trout 

fishery that sustains economic support for local businesses and 

Coconino County.

 Lees Ferry fishery contributed in excess of $16.8 million to the 

State’s economy and supported 251 jobs in Arizona (Fedler

2014). 
 Impaired aquatic food base

 Flow regimes 

 RBT population that exceeds 

the river’s carrying capacity

 Invasive species and disease

 Drought and climate change

 Status of endangered fishes 

down river
 The current food base is composed 

of a relatively few varieties of 

invertebrates, all of which are 

small and limits trout growth to 

preferred sizes

The EPT index (may, caddis and stone flies) for the Lee Ferry 

reach is zero, which limits trout growth and may also impacts 

the growth of other fishes, such as humpback chub

“Bug Flows” combined with EPT translocations may enhance 

recruitment and survival of a healthy and robust EPT 

population.
 Dam operations: Maintain the current MLFF release pattern. Some 

modification of the current flow regime may be needed to support the 

establishment of a more diverse and stable food base.

 Spring high flows. Use high flow releases in the spring as a way to improve 

the aquatic food base and enhance trout spawning and recruitment, when 

needed.

 Trout Management Flows. Carefully test trout management flows as a 

means to control the density of young trout and possibly benefit 

humpback chub. As an alternative to TMFs, mechanical removal may be 

used to reduce young trout densities in the reach

 Minimum flows. Avoid minimum flows below 8000 cfs especially when 

water temperatures are high and food production is low.

 Fall HFEs: Implement fall high flows per the 2011 Environmental 

Assessment and as part of an experimental design to further evaluate trout

response in both Lees Ferry and Marble Canyon, as well as food base and 

other resources.

 Equalization Flows: Examine the impact of sustained periods of high flows 

and assess whether it is feasible to provide greater flexibility in meeting 

annual delivery requirements from Lake Powell to Lake Mead. 
Recent studies indicate that amount of water in Lake 

Powell will likely decrease in the future as a result of 

increased water demands and climate change.

Lower Lake Powell levels will result in warmer water 

releases from dam which would seriously impact the 

Lees Ferry trout fishery and lead to an invasions of 

cool and warm water fishes into Grand Canyons 

National Park. 

Implement a water temperature control device that 

has the capacity to release both cold and warm water 

from the Glen Canyon Dam. 
 Stocking used only when there is a catastrophic fisheries 

failure.

 Complete re-stocking protocols and the necessary 

environmental compliance to allow for stocking. 

 Stock with non reproducing rainbow trout and/or with trout 

translocated from Marble Canyon. 

 Allow for immediate emergency stocking in response to a 

catastrophic fisheries failure. (Emergency stocking falls outside 

the guidelines of the CFMP).
Fish kills have been documented on at least two 

occasions due to the low amounts of dissolved 

oxygen being released from the dam. 

Action plan should be developed by the Bureau of 

Reclamation to reduce or avoid the potential effects 

to aquatic resources when low DO conditions 

emerge. 

In addition, dissolved oxygen levels should be made 

publically available at Glen Canyon Dam in addition to 

at the Lees Ferry gage. 
 Maintain a robust monitoring 

program to assess the status of the 

resource and determine when various 

triggers are met

 Trout size, condition and abundance

 Angler catch and satisfaction

 Invasive species

 Water quality and quantity

 Periodic monitoring of channel 

geomorphology

 Periodic monitoring of riparian 

vegetation
 Restore native riparian vegetation in the Lees

Ferry reach.

 Assess the feasibility of using dead tamarisk to

enhance aquatic productivity and fish habitat in

the Lees Ferry reach.
 Proactive effort to identify actions 

to maintain/enhance the trout 

fishery w/o impacting native fish 

downriver

 Recommendations effectively 

balance Colorado River resource 

values below Glen Canyon Dam

 Tier off the NPS Fishery Plan and 

GCD AMP Desired Future conditions

 Plan will guide input to the EIS and 

Fish and Wildlife Coordination Act 

Report

 Draft available for review by May 1; 

finalize by June 15.
Photo by: George Andrejko

John Hamill

jhamill@trcp.o

928 606-4234