U.S. Department of the Interior

U.S. Geological Survey

Modeling Tools for Management: 

Recreation in Glen and Grand Canyons

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

Glen Canyon Dam Adaptive Management Program, Annual Reporting Meeting, January 20, 2021 

U. S. Department of Interior

U.S. Geological Survey

Photo Credit: Bureau of Reclamation
Photo Credit: Bureau of Reclamation

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Introduction
Trout Fishery and 

Recreational Experience

• Resource Goal: Achieve a healthy high-quality 

recreational trout fishery in Glen Canyon 

National Recreation Area...

• Resource Goal: Maintain and improve the 

quality of recreational experiences for the 

users of the Colorado River ecosystem. 

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Photo Credit: Bureau of Reclamation
Measures of Recreational Experience

• Performance metrics

– Recreation, visitor use, and experience as related 

to fishing, boating, and camping activities in the 

Colorado River...

• Impact topics

– Socioeconomics, including recreational use values, 

..., employment and income, ...

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Photo Credit: Bureau of Reclamation
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Photo Credit: Bureau of Reclamation
Glen Canyon Angler Participation

6

0

260

627

576

620

328

483

450

516

449 454

162

0

100

200

300

400

500

600

700

Lees Ferry Angler Trips

U.S. Department of Interior, 2016
Glen Canyon Performance Metrics

• Glen Canyon Rafting Metric: Estimates the 

number of visitors unable to participate in day 

rafting in Glen Canyon due to high flows. 

• Catch Rate Index (number/hr). For age 2+ fish.

• Number of Trout >16 in. Total length.

• Glen Canyon Inundation Metric: Accounts for 

flows that impact recreational sites and 

recreational uses within the Glen Canyon 

reach.

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Photo Credit: Bureau of Reclamation
Glen Canyon Inundation Metric (1)

0.0

0.2

0.4

0.6

0.8

1.0

3,000 7,000 11,000 15,000 19,000 23,000

Glen Canyon Inundation Index

Constant Colorado River flow in cubic feet per second

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Glen Canyon Inundation Metric (2)

0.0

0.2

0.4

0.6

0.8

1.0

3,000 7,000 11,000 15,000 19,000 23,000

Glen Canyon Inundation Index

Constant Colorado River flow in cubic feet per second

Glen Canyon Inundation Metric

Normalized Net Evonomc Value

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Glen Canyon Inundation Metric (3)

10

$0

$50

$100

$150

$200

$250

0.0

0.2

0.4

0.6

0.8

1.0

3,000 7,000 11,000 15,000 19,000 23,000

Angler Economic Value per Trip ($2015)

Glen Canyon Inundation Index

Constant Colorado River flow in cubic feet per second

Glen Canyon Inundation Metric

Net Economic Value
Glen Canyon Angler Preferences

11

125

196

108

216 221

179

94

226

3,000 10,000 25,000 40,000

$0

$50

$100

$150

$200

$250

Net Economic Value per Trip ($2015)

Constant Colorado River flow in cubic feet per second

Bishop et al. 1987

Meldrum et al. In Prep

Bair et al. 2016
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Photo Credit: Bureau of Reclamation
Participation

13

157 259

803

550 624 595 568 517 652 609

350 294

955

3455

3922 3921

3310

1609

212

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Upper Grand Canyon Whitewater Trips

Commercial Whitewater

Private Whitewater

Upper Grand Canyon Whitewater 

U.S. Department of Interior, 2016
Grand Canyon Performance Metrics (1)

• Camping Area Index: Accounts for optimal campsite area 

building and maintenance flows and sediment load.

• Navigational Risk Index: Measure of navigation difficulty 

based on the number of days during which the daily minimum 

flow was less than 8,000 cfs.

• Fluctuation Index: Measures the degree to which 

combinations of flows and fluctuations are within a range 

identified as preferable by experienced boat guides.

• Time Off River Index: Relates the level of flows to visitors 

being able to spend time ashore visiting attractions. 

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Photo Credit: Bureau of Reclamation
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0.0

0.2

0.4

0.6

0.8

1.0

3,000 7,000 11,000 15,000 19,000 23,000 27,000 31,000

Recreational Expericnce Indecies

Constant Colorado River flow in cubic feet per second

Camping Area Index

Time Off River Index

Grand Canyon Performance Metrics (2)
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$636

$1,235

$1,378

$1,118 $1,237 $1,263 

$1,050 

$560 

$0

$200

$400

$600

$800

$1,000

$1,200

$1,400

$1,600

Economic Value per Trip ($2015)

Colorado River Flow in cubic feet per second

Neher et al. 2017 (2015 $)

Bishop et al. 1987 (2015$ adjusted

median household income)
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Photo Credit: Bureau of Reclamation