Proceedings of the 

Fiscal Year 2022

Annual Reporting Meeting 

to the Glen Canyon Dam 

Adaptive Management Program 

Prepared by

U.S. Geological Survey

Southwest Biological Science Center

Grand Canyon Monitoring and Research Center

Flagstaff, Arizona

January 24-25, 2023, Phoenix, Arizona
Cover: Little Colorado River, Grand Canyon National Park 

Photo by Lucas Bair, U.S. Geological Survey, Southwest Biological Science Center
U.S. Geological Survey

Grand Canyon Monitoring and 

Research Center

Proceedings of the 

Fiscal Year 2022

Annual Reporting Meeting 

to the Glen Canyon Dam 

Adaptive Management Program 

January 24-25, 2023, Phoenix, Arizona

Prepared by

U.S. Geological Survey

Southwest Biological Science Center

Grand Canyon Monitoring and Research Center

Flagstaff, Arizona

U.S. Department of the Interior

U.S. Geological Survey
Table of Contents

Introduction............................................................................................................................................................................... 1

Table 1: LTEMP Resource Goals........................................................................................................................................ 3

Archaeological and Cultural Resources..................................................................................................................... 3

Natural Processes ............................................................................................................................................................... 3

Humpback Chub .................................................................................................................................................................. 4

Tribal Resources ................................................................................................................................................................. 4

Recreational Experience.................................................................................................................................................. 5

Other Native Fish................................................................................................................................................................ 6

Sediment................................................................................................................................................................................. 6

Hydropower and Energy ................................................................................................................................................. 7

Rainbow Trout Fishery..................................................................................................................................................... 7

Nonnative Invasive Species ............................................................................................................................................ 8

Riparian Vegetation........................................................................................................................................................... 8

Table 2: Project Elements in the FY 2021-23 Triennial Work Plan.................................................................... 9

Project A: Streamflow, Water Quality, and Sediment Transport and Budgeting in the Colorado River 

Ecosystem.................................................................................................................................................................................10

Goals and Objectives........................................................................................................................................................10

Science Questions Addressed & Results..................................................................................................................10

Project Elements ...............................................................................................................................................................10

References ...........................................................................................................................................................................14

Project A Budget................................................................................................................................................................16

Project A Deliverables: Streamflow, Water Quality, and Sediment Transport and Budgeting in the 

Colorado River Ecosystem............................................................................................................................................16

Project B: Sandbar and Sediment Storage Monitoring and Research.............................................................18

Goals and Objectives........................................................................................................................................................18

Science Questions Addressed & Results..................................................................................................................18

Project Elements ...............................................................................................................................................................18

References ...........................................................................................................................................................................24

Project B Budget................................................................................................................................................................25

Project B Deliverables: Sandbar and Sediment Storage Monitoring and Research ..............................26

Project C: Riparian Vegetation Monitoring and Research...................................................................................28

Goals and Objectives........................................................................................................................................................28

Project Elements ...............................................................................................................................................................28
References ...........................................................................................................................................................................33

Project C Budget................................................................................................................................................................34

Project C Deliverables: Riparian Vegetation Monitoring and Research.....................................................34

Project D: Geomorphic Effects of Dam Operations and Vegetation Management for Archaeological 

Sites .............................................................................................................................................................................................36

Goals and Objectives........................................................................................................................................................36

Project Elements ...............................................................................................................................................................36

References ...........................................................................................................................................................................46

Project D Budget ...............................................................................................................................................................48

Project D Deliverables: Geomorphic Effects of Dam Operations and Vegetation Management for 

Archaeological Sites.........................................................................................................................................................49

Project E: Controls on Ecosystem Productivity: Nutrients, Flow and Temperature ................................50

Goals and Objectives........................................................................................................................................................50

Science Questions Addressed & Results..................................................................................................................50

Project Elements ...............................................................................................................................................................51

References ...........................................................................................................................................................................58

Project E Budget................................................................................................................................................................59

Project E Deliverables: Controls on Ecosystem Productivity: Nutrients, Flow and Temperature..60

Project F: Aquatic Invertebrate Ecology .....................................................................................................................62

Goals and Objectives........................................................................................................................................................62

Science Questions Addressed & Results..................................................................................................................63

Project Elements ...............................................................................................................................................................63

References ...........................................................................................................................................................................66

Project F Budget................................................................................................................................................................66

Project F Deliverables: Aquatic Invertebrate Ecology.......................................................................................67

Project G: Humpback Chub Population Dynamics throughout the Colorado River Ecosystem...........69

Goals and Objectives........................................................................................................................................................69

Project Elements ...............................................................................................................................................................69

References ...........................................................................................................................................................................76

Project G Budget................................................................................................................................................................77

Project G Deliverables: Humpback Chub Population Dynamics throughout the Colorado River 

Ecosystem............................................................................................................................................................................77

Project H: Salmonid Research and Monitoring ........................................................................................................79

Goals and Objectives........................................................................................................................................................79

Project Elements ...............................................................................................................................................................79
References ...........................................................................................................................................................................89

Project H Budget ...............................................................................................................................................................91

Project H Deliverables: Salmonid Research and Monitoring..........................................................................92

Project I: Warm-Water Native and Nonnative Fish Research and Monitoring...........................................93

Goals and Objectives........................................................................................................................................................93

Science Questions Addressed & Results..................................................................................................................94

Project Elements ...............................................................................................................................................................94

References ........................................................................................................................................................................100

Project I Budget..............................................................................................................................................................101

Project I Deliverables: Warm-Water Native and Nonnative Fish Research and Monitoring .........101

Project J: Socioeconomic Research in the Colorado River Ecosystem.........................................................102

Goals and Objectives.....................................................................................................................................................102

Project Elements ............................................................................................................................................................102

References ........................................................................................................................................................................105

Project J Budget..............................................................................................................................................................107

Project J Deliverables: Socioeconomic Research in the Colorado River Ecosystem ..........................107

Project K: Geospatial Science and Technology......................................................................................................108

Goals and Objectives.....................................................................................................................................................108

Project Elements ............................................................................................................................................................108

References ........................................................................................................................................................................114

Project K Budget.............................................................................................................................................................115

Project K Deliverables: Geospatial Science and Technology .......................................................................115

Project L: Remote Sensing Overflight in Support of Long-Term Monitoring and LTEMP...................118

Goals and Objectives.....................................................................................................................................................118

Project Elements ............................................................................................................................................................119

Element L.1.................................................................................................................................................................. 119

Project L Budget.............................................................................................................................................................122

References ........................................................................................................................................................................122

Project M: Leadership, Management, and Support .............................................................................................123

Goals and Objectives.....................................................................................................................................................123

Project M Budget............................................................................................................................................................124

Logistics Budget.............................................................................................................................................................124

Project N: Hydropower Monitoring and Research ..............................................................................................125

Goals and Objectives.....................................................................................................................................................125
Science Questions Addressed & Results...............................................................................................................125

References ........................................................................................................................................................................127

Project N Budget ............................................................................................................................................................128

Project N Deliverables: Hydropower Monitoring and Research................................................................128

Project O: Is Timing Really Everything? Evaluating Resource Response to Spring Disturbance Flows

....................................................................................................................................................................................................129

Goals and Objectives.....................................................................................................................................................129

Project Elements ............................................................................................................................................................130

References ........................................................................................................................................................................132

Project O Budget ............................................................................................................................................................133

Project O Deliverables: Is Timing Really Everything? Evaluating Resource Response to Spring 

Disturbance Flows.........................................................................................................................................................133

Appendix 1: Lake Powell Water-Quality Monitoring..........................................................................................134

References ........................................................................................................................................................................139

Appendix 1 Budget........................................................................................................................................................141

Appendix 1 Deliverables: Lake Powell Water-Quality Monitoring ...........................................................141

Appendix 2: Deliverables (Products), All Projects...............................................................................................143

Project A Deliverables: Streamflow, Water-Quality, and Sediment Transport and Budgeting in the 

Colorado River Ecosystem.........................................................................................................................................143

Project B Deliverables: Sandbar and Sediment Storage Monitoring and Research ...........................144

Project C Deliverables: Riparian Vegetation Monitoring and Research..................................................145

Project D Deliverables: Geomorphic Effects of Dam Operations and Vegetation Management for 

Archaeological Sites......................................................................................................................................................146

Project E Deliverables: Controls on Ecosystem Productivity: Nutrients, Flow and Temperature

...............................................................................................................................................................................................147

Project F Deliverables: Aquatic Invertebrate Ecology....................................................................................148

Project G Deliverables: Humpback Chub Population Dynamics throughout the Colorado River 

Ecosystem.........................................................................................................................................................................150

Project H Deliverables: Salmonid Research and Monitoring.......................................................................151

Project I Deliverables: Warm-Water Native and Nonnative Fish Research and Monitoring .........152

Project J Deliverables: Socioeconomic Research in the Colorado River Ecosystem ..........................152

Project K Deliverables: Geospatial Science and Technology .......................................................................153

Project N Deliverables: Hydropower Monitoring and Research................................................................155

Project O Deliverables: Is Timing Really Everything? Evaluating Resource Response to Spring 

Disturbance Flows.........................................................................................................................................................155

Appendix 3: Budgets, All Projects...............................................................................................................................156
Project A Budget.............................................................................................................................................................156

Project B Budget.............................................................................................................................................................156

Project C Budget.............................................................................................................................................................157

Project D Budget ............................................................................................................................................................157

Project E Budget.............................................................................................................................................................158

Project F Budget.............................................................................................................................................................158

Project G Budget.............................................................................................................................................................159

Project H Budget ............................................................................................................................................................159

Project I Budget..............................................................................................................................................................160

Project J Budget..............................................................................................................................................................160

Project K Budget.............................................................................................................................................................161

Project L Budget.............................................................................................................................................................161

Project M Budget............................................................................................................................................................162

Logistics Budget.............................................................................................................................................................162

Project N Budget ............................................................................................................................................................163

Project O Budget ............................................................................................................................................................163

Budget Summary – Adaptive Management Program Total (without Lake Powell Agreement and 

without Project O).........................................................................................................................................................164

Appendix 1 Budget........................................................................................................................................................164
1

Introduction 

Following is the U.S. Geological Survey (USGS), Southwest Biological Science Center (SBSC), 

Grand Canyon Monitoring and Research Center’s (GCMRC), Proceedings of the Fiscal Year (FY)

2022 Annual Reporting Meeting to the Glen Canyon Dam Adaptive Management Program

(GCDAMP). This proceedings report is prepared primarily for the Bureau of Reclamation to 

account for work conducted and products delivered by GCMRC and cooperators in FY 2022, and

to inform the Technical Work Group of science activities1 conducted in support of the Glen

Canyon Dam Adaptive Management Program, as reported out during the Annual Reporting 

Meeting on January 24-25, 2023. 

This document contains project reports for activities conducted in FY 20222 as part of GCMRC’s

FY 2021-23 Triennial Work Plan3. The research and monitoring activities described in this 

document help inform progress toward the 11 resource goals identified in the Glen Canyon

Dam Long-Term Experimental and Management Plan (LTEMP) Environmental Impact Statement 

and Record of Decision (Table 1). Tables 1 and 2 present crosswalks between GCMRC’s projects 

and the LTEMP Resource Goals, including connections to dam operations and experimental

actions. 

This document also contains a report concerning USGS activities conducted as part of the Lake 

Powell Water-Quality Monitoring Program (Appendix 1). The Deliverables (Products) are

presented at the end of the report, in Appendix 2, and project budgets are listed in each project

and also compiled together as Appendix 3. 

1 All handling of fish by GCMRC and all cooperating agencies was done according to standardized methods 

developed specifically for Grand Canyon (Persons and others, 2015). These methods describe how to handle fish 

safely and ethically during monitoring and research activities. SBSC is in the process of standing up an Institutional 

Animal Care and Use Committee (IACUC) per new requirements of the US Geological Survey's Ecosystem Mission 

Area (https://www.usgs.gov/mission-areas/ecosystems/usgs-ecosystems-mission-area-animal-welfare-assurance). 

Persons, W.R., Ward, D.L., and Avery, L.A., 2015, Standardized methods for Grand Canyon fisheries research 2015 

(ver. 1.1, January 2015): U.S. Geological Survey, Techniques and Methods, book 2, chapter A12, 19 p., 

https://www.usgs.gov/publications/standardized-methods-grand-canyon-fisheries-research-2015. 

2 This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for 

timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is 

provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages 

resulting from the authorized or unauthorized use of the information. Any use of trade, product, or firm names is 

for descriptive purposes only and does not imply endorsement by the U.S. Government. 

3 U.S. Department of the Interior, 2020, Glen Canyon Dam Adaptive Management Program Triennial Budget and 

Work Plan—Fiscal Years 2021-2023—Final approved by the Secretary of the Interior—December 2, 2020: Flagstaff, 

Ariz., U.S. Geological Survey, Grand Canyon Monitoring and Research Center, and Salt Lake City, Utah, Bureau of 

Reclamation, Upper Colorado Region, 384 p., http://gcdamp.com/images_gcdamp_com/5/5d/GCMRC_TWP2021-

23_December2_2020_ApprovedBySecretary.pdf
2

Low elevations in Lake Powell reservoir during FY 2022 contributed to this year being one 

marked by numerous extremes. Some notable extremes that were observed during FY 2022 

included record high release temperatures (> 20°C, the warmest in over 50 years), record low 

concentrations of dissolved oxygen (< 5 mg/L measured immediately downstream of the dam 

from August 3 to October 27, 2022, a total of 85 days), and high captures of nonnative warmwater fish species across multiple monitoring projects. 

In response to low reservoir elevations and numerous observations of nonnative warm-water 

species during FY 2022, two new compliance efforts were initiated, and GCMRC provided input, 

modeling, and other support to inform both of these compliance efforts (i.e., Supplemental 

Environmental Impact Statement for Near-term Colorado River Operations and Smallmouth 

Bass Environmental Assessment). 

FY 2022 was also marked by a robust monsoon season and numerous floods on the Paria River, 

Little Colorado River, and other tributaries. The active monsoon season in FY 2022 created a 

positive sand mass-balance in Marble Canyon and favorable sediment conditions for testing a 

High-Flow Experiment (HFE), but an HFE was not ultimately approved in fall 2022 owing to a 

variety of factors including low Lake Powell reservoir elevations. 

In FY 2022, GCMRC scientists and collaborators published numerous peer-reviewed journal 

articles, reports, and data releases. Below, we highlight one of the FY 2022 products that 

integrates research disciplines, spans multiple projects, and provides scientific findings from the

Macroinvertebrate Production Flows, which were tested in FY 2022: 

Deemer, B.R., Yackulic, C.B., Hall, R.O., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J., Topping, 

D.J., Voichick, N., and Yard, M., 2022, Daily flow fluctuations associated with hydropower 

generation reduce gross primary productivity up to 400 kilometers downstream in a regulated 

river: Proceedings of the National Academy of Sciences NEXUS, v. 1, p. 1–12, 

https://doi.org/10.1093/pnasnexus/pgac094. 

Summary: Algae production fuels many river food webs including those of the 

Colorado River. This paper compares rates of algae production downstream of Glen 

Canyon Dam during load following hydropower operations to those during 

experimental Bug Flows in 2018 and 2019. The paper demonstrates increased algae 

production during Bug Flows (weekend) water throughout the 425-kilometer-long 

segment of Colorado River compared to fluctuating flows during weekdays. Rates of 

algae production during steady-low flows were 41% higher than during load following 

flows, mostly owing to large reductions in sediment-driven turbidity. We estimate that 

experimental Bug Flows increased springtime carbon fixation by 0.27 g C m−2 d−1, 

which is ecologically meaningful considering median C fixation in 356 US rivers of 0.44 

g C m−2 d−1 and the fact that native fish populations in the Colorado River are foodlimited. 
3

Table 1: LTEMP Resource Goals

Archaeological and Cultural Resources

LTEMP Resource Goal Project

Maintain the integrity of potentially 

affected National Register of 

Historic Places (NRHP)-eligible or 

listed historic properties in place, 

where possible, with preservation 

methods employed on a sitespecific basis.

Project D examines how flow and non-flow actions will 

affect the long-term preservation of cultural resources 

and other culturally-valued and ecologically important 

landscape elements located within the Colorado River 

ecosystem (CRe).

Natural Processes

LTEMP Resource Goal Project

Restore, to the extent practicable, 

ecological patterns and processes 

within their range of natural 

variability, including the natural 

abundance, diversity, and genetic 

and ecological integrity of the plant 

and animal species native to those 

ecosystems.

Addressed by Projects A, C, E, and F through 1) 

monitoring of stage, discharge, water temperature, 

specific conductance, dissolved oxygen, turbidity, 

suspended-sediment concentration, and particle size 

at stream/river locations throughout the CRe, 2) 

monitoring changes in riparian vegetation using fieldcollected data and digital imagery, developing 

predictive models of vegetation composition as it 

relates to hydrological regime, and providing 

monitoring protocols and decision support tools for 

active vegetation management, 3) identifying 

processes that drive spatial and temporal variation in 

nutrients and temperature within the CRe and 

establishing quantitative and mechanistic links among 

these ecosystem drivers, primary production, and 

higher trophic levels, and 4) tracking the response of 

aquatic food base organisms to flow and non-flow 

actions. 
4

Humpback Chub

LTEMP Resource Goal Project

Meet humpback chub recovery 

goals, including maintaining a selfsustaining population, spawning 

habitat, and aggregations in the 

Colorado River and its tributaries 

below the Glen Canyon Dam.

Addressed by Projects E, F, G, I, and J through 1) 

identifying processes that drive spatial and temporal 

variation in nutrients and temperature within the CRe 

and establishing quantitative and mechanistic links 

among these ecosystem drivers, primary production, 

and higher trophic levels, 2) tracking the response of 

aquatic food base organisms to flow and non-flow 

actions, 3) monitoring of humpback chub populations, 

dynamics, and condition in aggregations in the 

mainstem Colorado River both upstream and 

downstream of the confluence with the Little 

Colorado River and within the Little Colorado River, 4) 

monitoring the status and trends of native and 

nonnative fish that occur in the CRe from Lees Ferry

to Lake Mead, and 5) identifying preferences for, and 

values of, native fish like the humpback chub and 

evaluating how preferences and values are influenced 

by Glen Canyon Dam operations.

Tribal Resources

LTEMP Resource Goal Project

Maintain the diverse values and 

resources of traditionally associated 

Tribes along the Colorado River 

corridor through Glen, Marble, and 

Grand Canyons.

Addressed by Project J through identifying Tribes’ 

preferences for, and values of, downstream resources 

and evaluating how these preferences and values are 

influenced by Glen Canyon Dam operations.
5

Recreational Experience

LTEMP Resource Goal Project

Maintain and improve the quality of 

recreational experiences for the 

users of the CRe. Recreation 

includes, but is not limited to, 

flatwater and whitewater boating, 

river corridor camping, and angling 

in Glen Canyon.

Addressed by Projects B, C, and H through 1) tracking 

the effects of experimental actions such as High-Flow 

Experiments (HFEs) on sandbars, monitoring the 

cumulative effect of successive HFEs and intervening 

operations on sandbars and sand conservation, and 

investigating the interactions between dam operations 

and sand transport, and eddy sandbar dynamics, 2) 

monitoring changes in riparian vegetation using fieldcollected data and digital imagery, developing 

predictive models of vegetation composition as it 

relates to hydrological regime, and providing 

monitoring protocols and decision support tools for 

active vegetation management, and 3) monitoring the 

status and trends of both rainbow and brown trout 

upstream of Lees Ferry in Glen Canyon as well as 

increase understanding of key factors such as density 

and recruitment, prey availability, and variables that 

control the abundance and growth of the trout 

population.
6

Other Native Fish

LTEMP Resource Goal Project

Maintain self-sustaining native fish 

species populations and their 

habitats in their natural ranges on 

the Colorado River and its 

tributaries.

Addressed by Projects E, F, G, and I through 1) 

identifying processes that drive spatial and temporal 

variation in nutrients and temperature within the CRe 

and establishing quantitative and mechanistic links 

among these ecosystem drivers, primary production, 

and higher trophic levels, 2) tracking the response of 

aquatic food base organisms to flow and non-flow 

actions, 3) monitoring of humpback chub populations, 

dynamics, and condition in aggregations in the 

mainstem Colorado River both upstream and 

downstream of the confluence with the Little Colorado 

River and within the Little Colorado River, and 4) 

monitoring the status and trends of native and 

nonnative fish that occur in the Colorado River 

ecosystem from Lees Ferry to Lake Mead.

Sediment

LTEMP Resource Goal Project

Increase and retain fine sediment 

volume, area, and distribution in the 

Glen, Marble, and Grand Canyon 

reaches above the elevation of the 

average base flow for ecological, 

cultural, and recreational purposes.

Addressed by Projects A and B through 1) monitoring 

of stage, discharge, water temperature, specific 

conductance, dissolved oxygen, turbidity, suspendedsediment concentration, and particle size at 

stream/river locations in the Glen, Marble, and Grand 

Canyon reaches and 2) tracking the effects of 

experimental actions such as HFEs on sandbars, 

monitoring the cumulative effect of successive HFEs 

and intervening operations on sandbars and sand 

conservation, and investigating the interactions 

between dam operations and sand transport and eddy 

sandbar dynamics.
7

Hydropower and Energy

LTEMP Resource Goal Project

Maintain or increase Glen Canyon 

Dam electric energy generation, 

load following capability, and ramp 

rate capability, and minimize 

emissions and costs to the greatest 

extent practicable, consistent with 

improvement and long-term 

sustainability of downstream 

resources.

Addressed by Project N through identifying, 

coordinating, and collaborating on monitoring and 

research opportunities associated with operational 

experiments at Glen Canyon Dam to meet hydropower 

and energy resource objectives.

Rainbow Trout Fishery

LTEMP Resource Goal Project

Achieve a healthy, high-quality 

recreational rainbow trout fishery in 

Glen Canyon and reduce or 

eliminate downstream trout 

migration consistent with National 

Park Service fish management and 

Endangered Species Act 

compliance.

Addressed by Project H, E, F, and G through 1) 

monitoring the status and trends of both rainbow and 

brown trout upstream of Lees Ferry in Glen Canyon as 

well as increase understanding of key factors such as 

density and recruitment, prey availability, and 

variables that control the abundance and growth of 

the trout population, 2) identifying processes that 

drive spatial and temporal variation in nutrients and 

temperature within the CRe and establishing 

quantitative and mechanistic links among these 

ecosystem drivers, primary production, and higher 

trophic levels, 3) tracking the response of aquatic food 

base organisms to flow and non-flow actions, and 4) 

monitoring of humpback chub populations, dynamics, 

and condition in aggregations in the mainstem 

Colorado River both upstream and downstream of the 

confluence with the Little Colorado River and within 

the Little Colorado River.
8

Nonnative Invasive Species

LTEMP Resource Goal Project

Minimize or reduce the presence 

and expansion of aquatic nonnative 

invasive species.

Addressed by Projects F, I, G, and J through 1) tracking 

the response of aquatic food base organisms to flow 

and non-flow actions, 2) monitoring the status and 

trends of native and nonnative fish that occur in the 

CRe from Lees Ferry to Lake Mead, 3) monitoring of 

humpback chub populations, dynamics, and condition 

in aggregations in the mainstem Colorado River both 

upstream and downstream of the confluence with the 

Little Colorado River and within the Little Colorado 

River, and 4) identifying preferences for, and values of, 

nonnative fish like the rainbow trout and evaluating 

how preferences and values are influenced by Glen 

Canyon Dam operations.

Riparian Vegetation 

LTEMP Resource Goal Project

Maintain native vegetation and 

wildlife habitat, in various stages of 

maturity, such that they are diverse, 

healthy, productive, self-sustaining, 

and ecologically appropriate.

Addressed by Project C through monitoring changes in 

riparian vegetation using field-collected data and 

digital imagery, developing predictive models of 

vegetation composition as it relates to hydrological 

regime, and providing monitoring protocols and 

decision support tools for active vegetation 

management. 
9

Table 2: Project Elements in the FY 2021-23 Triennial Work Plan

Project Elements in the FY 2021-23 Triennial Work Plan that address some aspect of the Long-Term Experimental and Management Plan 

(LTEMP) Resource Goals relative to LTEMP dam operations and experimental actions. Gray boxes indicate no relevance.

LTEMP General 

Dam Operations & 

Experimental Actions

Archeological & Cultural ResourcesNatural ProcessesHumpback ChubHydropower & EnergyOther Native FishRecreational ExperienceSedimentTribal ResourcesRainbow Trout FisheryNonnative Invasive SpeciesRiparian Vegetation

General dam operations D.1/D.2 

A.2

E.1-3 

F.1-4

G.1-6

I.1 

J.1

N.1 G.1-6 

I.1 

A.1/A.3

B.1/B.2 

J.1/J.3

A.1/A.3

B.1/B.2/B.3 

D.3

D.3 H.1/H.2/H.4 

I.1 

H.3 

I.1-3 C.1/C.2/C.3

Fall High-Flow Experiments (HFE) > 96-

hr ≤ 45,000 ft3/s, in Oct. or Nov. D.1/D.2 

A.2

E.1-3 

F.1/F.2

G.1-6 

J.1 N.1 G.1-6 I.1 

A.1/A.3

B.1/B.2/B.6 

J.1/J.3

A.1/A.3 

B.2/B.6 H.1/H.2/H.4 H.3 

I.1-3 C.1/C.2/C.3

Fall HFE ≤ 96-hr ≤ 45,000 ft3/s, in Oct. 

or Nov. D.1/D.2

A.2

E.1-3 

F.1/F.2

G.1-6 

J.1 N.1 G.1-6 I.1 

A.1/A.3

B.1/B.2/B.6 

J.1/J.3

A.1/A.3 

B.2/B.6 H.1/H.2/H.4 H.3 

I.1-3 C.1/C.2/C.3

Humpback chub translocation G.7 

Larval humpback chub head-start 

program

G.7 

Macroinvertebrate production flows F.1/F.2/F.4

F.4

G.1-6 

J.1

N.1

F.4

G.1-6 

I.1

J.3 F.4 

H.1/H.2/H.4 I.1-3 

Mechanical removal of invasive fish

Mechanical removal of rainbow trout 

from Little Colorado River reach

Proactive spring HFE ≤ 45,000 ft3/s, in 

April, May or June D.1/D.2

A.2

E.1-3 

F.1/F.2

G.1-6 

J.1 N.1 G.1-6 I.1 

A.1/A.3

B.1/B.2/B.6 

J.1/J.3

A.1/A.3 

B.2/B.6 H.1/H.2/H.4 H.3 

I.1-3 C.1/C.2/C.3

Riparian vegetation restoration D.1/D.2 C.4

J.1/J.3 C.4

Spring HFE ≤ 45,000 ft3/s, in March or 

April D.1/D.2

A.2

E.1-3 

F.1/F.2

G.1-6 

J.1 N.1 G.1-6 I.1 

A.1/A.3

B.1/B.2/B.6 

J.1/J.3

A.1/A.3 

B.2/B.6 H.1/H.2/H.4 H.3 

I.1-3 C.1/C.2/C.3

Trout management flows N.1 H.1/H.2/H.4 H.3 C.1/C.2/C.3

Spring disturbance flow O.3 O.1/O.5 O.7 O.9 O.7 O.8/O.10 O.2/O.10 O.2 O.6 O.6 O.4 LTEMP Resource Goal
10

Project A: Streamflow, Water Quality, and Sediment Transport 

and Budgeting in the Colorado River Ecosystem 

Goals and Objectives

The goal of Project A is to make high-resolution measurements of stage, discharge, water 

temperature, specific conductance, dissolved oxygen, turbidity, suspended-sediment 

concentration, and particle size at 8 mainstem and 16 tributary sites located throughout the 

CRe. These data are used to inform managers about the physical status of the Colorado River in 

the CRe and how this physical status is affected by dam operations in near real time. Therefore, 

in addition to addressing the LTEMP sediment goal, the data collection supports the LTEMP 

goals in the following nine resource areas: aquatic food base, archaeological and cultural 

resources, humpback chub, hydropower and energy, invasive fish species, natural processes, 

rainbow trout fishery, recreational experience, and riparian vegetation. Details of this ongoing 

project, including descriptions of the data-collection locations, are provided in the GCMRC FY

2021–23 Triennial Work Plan (TWP). 

Science Questions Addressed & Results

The results and hypothesis testing described below are completed via the collection, serving, 

and interpretation of data distributed among three project elements. The specific focus of each 

element is described in brief below, but please consult the FY 2021-23 Triennial Work Plan for 

additional information on this and the other elements of Project A listed herein.

Project Elements

Element A.1. Stream Gaging and Hydrologic Analyses

Element A.1 partially funds the collection, serving, and interpretation of continuous 15-minute 

measurements of stage and discharge on the mainstem Colorado River at USGS streamflow 

gaging stations located at river miles (RM) 0, 30, 61, 87, 166, and 225, and at gaging stations on 

the major tributaries and in a representative subset of the smaller tributaries.

Project Lead David Topping

Principal 

Investigator(s) (PI)

David Topping, USGS, GCMRC

Ronald Griffiths, USGS, GCMRC

David Dean, USGS, GCMRC

Email dtopping@usgs.gov

Telephone (928) 556-7396
11

Element A.2. Continuous Water-Quality Parameters

Element A.2 funds the collection, serving, and interpretation of continuous 15-minute 

measurements of water temperature, specific conductance (a measure of salinity), turbidity, 

and dissolved oxygen at the outlet of Glen Canyon Dam and at six mainstem Colorado River 

gaging stations. This element also funds episodic measurements of specific conductance 

associated with suspended-sediment samples collected in tributaries.

Element A.3. Sediment Transport and Budgeting

Element A.3 funds the collection, serving, and interpretation of continuous 15-minute 

measurements and episodic measurements of suspended sediment and bed sediment at gaging 

stations on the Colorado River and its tributaries. In addition, this project element funds 

interpretive work regarding the sand supply from the Paria and Little Colorado Rivers, and 

interpretive work regarding the effect of dam operations on sediment transport. 

There are two key hypotheses that guide the monitoring and research conducted under the 

three elements of Project A. Owing to the interlocking nature of the three elements, the 

hypotheses that guide Project A and the results from Project A cannot be easily segregated by 

element and are described together in this section.

• Hypothesis 1: Glen Canyon Dam can be operated such that the sand resources in the 

CRe are sustainable. Sustainable management of sand requires that sandbars and other 

high-elevation sandy deposits be maintained or increased while not depleting the 

overall amount of sand in the CRe.

• Hypothesis 2: Glen Canyon Dam can be operated such that the other CRe resources

affected by dam operations can be sustainably managed. In this usage, “dam 

operations” refers to the amount and quality of the water released from the dam,

where “amount” refers to stage and streamflow and “quality” refers to temperature, 

salinity, turbidity, and dissolved oxygen.

These hypotheses are paraphrased from the Long-Term Experimental and Management Plan

Environmental Impact Statement (LTEMP EIS; U.S. Department of Interior, 2016a, b) and from 

earlier goals, information needs, and strategic science questions formulated by the Glen 

Canyon Dam Adaptive Management Program (GCDAMP). 

The results from Project A during FY 2022 highlighted below are provided in two journal 

articles, three USGS reports (one published, one in layout at the USGS Science Publishing 

Network, and one in review), and two updated web applications described in the list of 

Deliverables below. Much of the monitoring data collected by this project, including those 

required to trigger, design, and evaluate a potential November 2022 HFE, were collected and 

posted to the project web application (https://www.gcmrc.gov/discharge_qw_sediment/). The 

sand supplied by the Paria River during the summer 2022 sand-accounting period (~1.5 million 

metric tons) was the second largest of any period where a fall HFE was considered. 
12

Because of the laboratory slow-down caused by a change in Project A’s funding structure 

between the previous TWP and the FY 2021–23 TWP, the laboratory analyses of many 

suspended-sediment samples from FY 2022 remain incomplete. Thus, unlike in years prior to 

2021, when this problem first arose, it will be relatively late in the subsequent fiscal year (FY

2023 in this case) when we post the final sediment data on Project A’s website. Given the 

multifaceted nature of Project A, only a few key results are listed herein. 

• A USGS Open-File Report submitted for review during FY 2022 (Griffiths and others, in

review) analyzing changes in sand storage during sediment years 2018–2020 (July 1,

2017, through June 30, 2020) provides additional support for the result in Topping and 

others (2021) that multi-year net sand accumulation is only possible in the Colorado

River between Lees Ferry and Diamond Creek during years when the tributary sand

supply exceeds ~130% of average and dam-released discharges are below the 1964-

2017 average. This Open-File Report extends the sediment-year 2003–2017 analyses in

Topping and others (2021) through sediment year 2020; this report is now in USGS

review with anticipated publication in 2023. Even though dam releases were slightly

below average during sediment years 2018–2020, the tributary sand supply was well 

below average during 2 of these 3 years, thereby leading to net erosion of sand from

Marble Canyon during the sediment-year 2018–2020 period. Thus, as concluded in

Topping and others (2021), maintaining a level of sand storage sufficient for maintaining

sandbars in the Colorado River may require timing periods of higher and lower damreleased discharge based on tributary sand-supply conditions. Whether the sand

resources of the Colorado River in Grand Canyon National Park can be sustainably 

managed in perpetuity therefore remains an open question (Topping and others, 2021).

• Gross primary production was increased throughout the CRe through reductions in daily

flow fluctuations at Glen Canyon Dam (Deemer and others, 2022, Proceedings of the 

National Academy of Sciences NEXUS). The reduction in both silt and clay concentration

and sand concentration caused by such reductions in the daily range in discharge

released from the dam led to reduced turbidity, and therefore greater gross primary

production throughout the ~425-km length of the CRe.

 

• A USGS Professional Paper (Topping and others, in press at the USGS Science Publishing 

Network) indicates that the changes in sand cross-sectional area among the cross

sections at the Marble Canyon dam sites are generally consistent with the flux-based

estimates and measurements showing at least ~24 million metric tons of sand erosion

from Marble Canyon between the 1963 closure of Glen Canyon Dam and 2017, mostly

during ~3–4 periods of higher dam releases (Topping and others, 2021). This result

provides further support for the conclusions of Topping and others (2021) that indicate 

that it remains unclear if sand can be sustainably managed in the CRe utilizing the 

available tributary supply of sand. In addition, this Professional Paper shows that 

incision into the Lake Mead deltaic deposits at the Bridge Canyon dam sites appears to 

be limited by bed-sediment grain size and downstream hydraulic controls. 
13

• Although an earlier study showed the presence of a slight positive bias in both 

suspended-sand concentration and grain size in measurements made by the depthintegrating suspended-sediment samplers used at the gaging stations in the CRe (Sabol

and Topping, 2013), further evaluation indicated that this sampler can collect unbiased 

suspended-sand data in the Colorado River (Sabol and others, 2022). This result helps 

inform the uncertainty in the continuous mass-balance sand budgets at

http://www.gcmrc.gov/discharge_qw_sediment/reaches/GCDAMP. 

• A new technique was developed for calculating sand bedload from repeat multibeam

sonar maps using data collected by Projects A and B near the Colorado River above

Diamond Creek near Peach Springs, AZ, gaging station (LeCoz and others, in press,

Water Resources Research). This particle-tracking-based method provides an improved

way to inform the estimates of sand bedload in the continuous mass-balance sand

budgets at http://www.gcmrc.gov/discharge_qw_sediment/reaches/GCDAMP used to 

design HFEs and evaluate the effect of dam operations on sand resources (Topping and

others, 2021; Griffiths and others, in review). 

• During FY 2022, the following changes in sand mass (shown in tabular form in Table 1)

occurred in the six reaches where continuous mass-balance sand budgets are

constructed by Project A. Sand accumulated in all five reaches of the CRe between Lees

Ferry and Diamond Creek during FY 2022. The changes in sand mass in this table are

preliminary and will likely change because we still have a large backlog of suspendedsediment samples to process (caused by a laboratory slow-down arising from funding 

issues and a USGS hiring slowdown). Data from 

(http://www.gcmrc.gov/discharge_qw_sediment/reaches/GCDAMP).
14

Table 1. Changes in sand mass during FY 2022 (preliminary results, do not cite)

References

Deemer, B.R., Yackulic, C.B., Hall, R.O., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J., Topping, 

D.J., Voichick, N., and Yard, M., 2022, Daily flow fluctuations associated with hydropower 

generation reduce gross primary productivity up to 400 kilometers downstream in a 

regulated river: Proceedings of the National Academy of Sciences NEXUS, v. 1, p. 1–12, 

https://doi.org/10.1093/pnasnexus/pgac094.

Grams, P.E., Schmidt, J.C., Wright, S.A., Topping, D.J., Melis, T.S., and Rubin, D.M., 2015, 

Building sandbars in the Grand Canyon: EOS, Transactions of the American Geophysical 

Union, v. 96, no. 11, p. 12–16, https://doi.org/10.1029/2015EO030349. 

Griffiths, R.E., Topping, D.J., and Unema, J.A., in review, Changes in sand storage in the Colorado 

River in Grand Canyon National Park from July 2017 through June 2020: U.S. Geological 

Survey Open-File Report. 

LeCoz, J., Perret, E., Camenen, B., Topping, D.J., Buscombe, D.D., Leary, K.C.P, Dramais, G., and 

Grams, P.E., in press, Mapping 2-D bedload rates throughout a sand-bed river reach from 

high-resolution acoustical surveys of migrating bedforms: Water Resources Research. 

Reach

Change in sand mass in metric tons during FY 2022; 

interpretation of change in bold uses criteria in 

Topping and others (2021)

Upper Marble Canyon 1,200,000±430,000

Deposition

Lower Marble Canyon 440,000±65,000

Deposition

Eastern Grand Canyon 430,000±300,000

Deposition

East-Central Grand Canyon 180,000±160,000*

Deposition

West-Central Grand Canyon 410,000±93,000*

Deposition

Western Grand Canyon and the Lake 

Mead Delta (Colorado River 

downstream from Diamond Creek)

470,000±23,000**

Deposition

*Data used to compute these values end in late August 2022 because the Colorado River above National Canyon n 

the Supai, AZ, gaging station had not been visited since August 30 at the time this report was completed.

**Data used to compute these values end in late early September 2022 because of instrument problems at the 

Colorado River above Diamond Creek near the Peach Springs, AZ, gaging station that will remain unresolved until 

backlogged suspended-sediment samples from this station get processed through the laboratory during FY 2023. 

These samples accumulated in the laboratory owing due to a USGS hiring slowdown.
15

Sabol, T.A., and Topping, D.J., 2013, Evaluation of intake efficiencies and associated sedimentconcentration errors in US D-77 bag-type and US D-96-type depth-integrating suspendedsediment samplers: U.S. Geological Survey Scientific Investigations Report 2012-5208, 88 p., 

http://dx.doi.org/10.3133/sir20125208. 

Sabol, T.A., Topping, D.J., Griffiths, R.E., and Dramais, G., 2022, Field investigation of subisokinetic sampling by the US D-96-type suspended-sediment sampler and its effect on 

suspended-sediment measurements: U.S. Geological Survey Open-File Report 2022-1077, 

14 p., https://doi.org/10.3133/ofr20221077.

Topping, D.J., Grams, P.E., Griffiths, R.E., Dean, D.J., Wright, S.A., and Unema, J.A., 2021, Selflimitation of sand storage in a bedrock-canyon river arising from the interaction of flow and 

grain size: Journal of Geophysical Research: Earth Surface, v. 126, e2020JF005565, 

https://doi.org/10.1029/2020JF005565. 

Topping, D.J., Hazel, J.E., Jr., Kaplinski, M., and Grams, P.E., in press, Resurvey of the Marble 

Canyon and Bridge Canyon dam sites in Grand Canyon National Park—Dam-induced 

changes in sediment storage and evidence supporting recent pre-dam bedrock incision: U.S. 

Geological Survey Professional Paper.

U.S. Department of Interior, 2011, Environmental assessment—Development and 

implementation of a protocol for high-flow experimental releases from Glen Canyon Dam, 

Arizona, 2011 through 2020: Salt Lake City, Utah, U.S. Department of Interior, Bureau of 

Reclamation, Upper Colorado Region, 176 p. plus appendices, 

https://www.usbr.gov/uc/envdocs/ea/gc/HFEProtocol/HFE-EA.pdf. 

U.S. Department of Interior, 2016a, Glen Canyon Dam Long-term Experimental and 

Management Plan final Environmental Impact Statement (LTEMP FEIS): U.S. Department of 

the Interior, Bureau of Reclamation, Upper Colorado Region, National Park Service, 

Intermountain Region, online, http://ltempeis.anl.gov/documents/final-eis/. 

U.S. Department of Interior, 2016b, Record of Decision for the Glen Canyon Dam Long-Term 

Experimental and Management Plan final Environmental Impact Statement (LTEMP ROD): 

Salt Lake City, Utah, U.S. Department of Interior, Bureau of Reclamation, Upper Colorado 

Region, National Park Service, Intermountain Region, 22 p. plus appendices, 

http://ltempeis.anl.gov/documents/docs/LTEMP_ROD.pdf. 
16

Project A Budget

Project A Deliverables: Streamflow, Water Quality, and Sediment Transport and 

Budgeting in the Colorado River Ecosystem

Presentations:

Because the COVID-19 pandemic is only now ending, no presentations were made at 

professional scientific meetings during FY 2022. One presentation was made to the GCDAMP at 

the January 2022 Annual Reporting Meeting.

Journal Articles:

Deemer, B.R., Yackulic, C.B., Hall, R.O., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J., Topping, 

D.J., Voichick, N., and Yard, M., 2022, Daily flow fluctuations associated with hydropower 

generation reduce gross primary productivity up to 400 kilometers downstream in a 

regulated river: Proceedings of the National Academy of Sciences NEXUS, v. 1, p. 1–12, 

https://doi.org/10.1093/pnasnexus/pgac094.

LeCoz, J., Perret, E., Camenen, B., Topping, D.J., Buscombe, D.D., Leary, K.C.P, Dramais, G., and 

Grams, P.E., in press, Mapping 2-D bedload rates throughout a sand-bed river reach from 

high-resolution acoustical surveys of migrating bedforms: Water Resources Research, 

https://doi.org/10.1029/2022WR032434.

USGS Reports:

Sabol, T.A., Topping, D.J., Griffiths, R.E., and Dramais, G., 2022, Field investigation of subisokinetic sampling by the US D-96-type suspended-sediment sampler and its effect on 

suspended-sediment measurements: U.S. Geological Survey Open-File Report 2022-1077, 

14 p., https://doi.org/10.3133/ofr20221077.

Burden

12.326%

Budgeted

Amount $485,907 $10,000 $58,500 $0 $392,587 $68,336 $1,015,330 

Actual

Spent $497,227 $2,431 $83,030 $0 $459,407 $71,822 $1,113,917 

(Over)/Under

Budget ($11,320) $7,569 ($24,530) $0 ($66,820) ($3,486) ($98,587)

FY21 Unspent Funds $135,000 FY22 Unspent Funds $36,413

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated unspent funds; etc.)

FY22 Comments:

-Overspent Salaries during FY22 is due to shortfall in the budget for essential project staff.

-Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

-Overspent Operating Expenses was for instrument repairs and replacements initiated in Q4 FY22 that will be completed in 

FY23.

-Overspending To other USGS Centers is due to rising costs for database/website design at Fort Collins and and EROS Scienece 

centers.

Project A Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
17

Topping, D.J., Hazel, J.E., Jr., Kaplinski, M., and Grams, P.E., in press at the USGS Science 

Publishing Network, Resurvey of the Marble Canyon and Bridge Canyon dam sites in Grand 

Canyon National Park—Dam-induced changes in sediment storage and evidence supporting 

recent pre-dam bedrock incision: U.S. Geological Survey Professional Paper.

Griffiths, R.E., Topping, D.J., and Unema, J.A., in review, Changes in sand storage in the Colorado 

River in Grand Canyon National Park from July 2017 through June 2020: U.S. Geological 

Survey Open-File Report.

Web Applications:

https://www.gcmrc.gov/discharge_qw_sediment/

Stage, discharge, sediment transport, water-quality, and sand-budget data are served through 

the USGS-GCMRC website. The database associated with this website is updated every day 

to month, depending on data type. This web-based application has been maintained to 

provide stakeholders, scientists, and the public with the ability to perform interactive online 

data visualization and analysis, including the on-demand construction of sand budgets and 

duration curves. These capabilities are unique in the world.

https://waterdata.usgs.gov/nwis

Stage, discharge, and water-quality data collected at 9 gaging stations by the USGS Utah and 

Arizona Water Science Centers are posted to this website every hour.
18

Project B: Sandbar and Sediment Storage Monitoring and 

Research

Goals and Objectives

The purposes of this project are to: a) track the effects of individual High-Flow Experiments 

(HFEs) on sandbars, b) monitor the cumulative effect of successive HFEs and intervening 

operations on sandbars, campsites, and sand conservation, and c) investigate the interactions 

between dam operations, sand transport, and eddy sandbar dynamics. This project addresses 

LTEMP resource goals for sediment by measurements of sandbars and sand storage in the river 

channel and by developing predictive tools for sand transport and sandbar response to dam 

operations. This project also addresses goals for recreational experience by measurements of 

campsite area and evaluation of campsites by the community science Adopt-a-Beach program. 

Outcomes from this project will be used to evaluate the effectiveness of the HFE protocol 

included in the 2016 Long-Term Experimental and Management Plan Record of Decision with 

respect to sandbar condition.

Science Questions Addressed & Results

Project Elements

Element B.1. Sandbar and Campsite Monitoring with Topographic Surveys and Remote Cameras

Project B.1 addresses the hypothesis that sandbar building during sand-enriched HFEs will

exceed sandbar erosion during periods between HFEs, such that sandbar size can be increased 

and maintained to result in long-term increases in sandbar volumes and campsite areas. This 

hypothesis is addressed through annual monitoring using topographic surveys, analysis of 

images from remote cameras, and advances in data management. 

The sandbar monitoring data consist of topographic surveys collected by total station (Hazel 

and others, 2022) and measurements of campsite area (Hadley and others, 2018). 

Project Lead Paul Grams

Principal 

Investigator(s) (PI)

Paul Grams, USGS, GCMRC

Keith Kohl, USGS, GCMRC

Robert Tusso, USGS, GCMRC

Gerard Salter, USGS, GCMRC

Matt Kaplinski, NAU

Katherine Chapman, NAU

Erich Mueller, SUU

Email pgrams@usgs.gov

Telephone (928) 266-6096
19

Data collected in October 2021 were presented at the Annual Reporting Meeting in January 

2022, and the most recent data, collected in October 2022, will be presented at the Annual 

Reporting Meeting in January 2023. 

Images from the remote cameras were retrieved in October 2021, February 2022, and October 

2022. The community science Adopt-a-Beach program was continued by the Grand Canyon 

River Guides.

In a recently completed summary of the sandbar monitoring data, Hazel and others (2022) 

showed that sand volume increased at 86% of the monitoring sites between 2004 and 2020 

owing to the seven HFEs that occurred during that period. In contrast, net erosion occurred 

between 1990 and 2003 – a period that included only one HFE in 1996. These findings 

demonstrate that the sand-enriched HFEs implemented under the HFE Protocol and LTEMP EIS

caused net increases in sandbar volume. Individually, each of the HFEs implemented since 2012 

resulted in substantial deposition at all sandbar types (Mueller and others, 2018; Grams, 2019; 

Hazel and others, 2022). The normalized volume of sand in narrow and medium reattachment 

bars averaged for the 2013-2021 period was 22% greater than for the 2009-2012 period (Figure 

1). For wide reattachment bars and upper pool bars the normalized sand volume was 12%

greater for the 2013-2021 period. Thus, even though many sites have experienced erosion, 

much of the HFE-deposited sand has persisted. Deposition of sand during HFEs has resulted in

temporary increases in campsite area; however, there has been a net long-term decline in 

campsite area caused by vegetation encroachment (Hadley and others, 2018). Although 

vegetation encroachment reduces campsite area (Hadley and others, 2018), it also promotes 

deposition and sand retention as described in a recently completed study by Butterfield and 

others (2020). 

In addition to the gradual erosion that typically follows deposition associated with HFEs (Hazel 

and others, 2010), many sandbars in Marble and Grand Canyons experienced dramatic episodes 

of erosion in 2021 and 2022 during summer thunderstorms. Hillslope runoff during these 

events resulted in the formation of gullies and deposition of debris on sandbar campsites 

(Figure 2). Similar damage caused during previous monsoon seasons was repaired by HFEs, 

which bury debris and fill gullies (Grams and others, 2018). 
20

Figure 1. Normalized sandbar volume June 1990 to October 2021 for each site type. Methods and normalization procedure are 

described by Hazel and others (2022). Error bars are standard error. Vertical dashed lines show the timing of HFEs. Sites were 

measured immediately following HFEs in 1996, 2004, and 2008 only. Beginning in 2009, measurements were made once 

annually in October. The HFEs have continued to result in deposition and sandbar measurements indicate that there has been 

some net increase in sandbar volume since the beginning of the HFE protocol in 2012 for narrow and medium reattachment bars 

and for wide reattachment and upper pool bars. There has been no net increase in the size of separation and undifferentiated 

bars. Please see https://www.usgs.gov/apps/sandbar/sites for site locations and most recent data for individual sites.

Figure 2. Photographs looking downstream at a sandbar campsite downstream from Tatahatso Wash at river mile (RM) 37.9 in 

Marble Canyon taken October 3, 2020 (left), and October 4, 2022 (right). Note person for scale. The erosion and deposition of 

debris occurred during a high-intensity summer thunderstorm on July 14, 2021. The sand routing model (Wright and others, 

2010) and the recently completed sandbar volume model (Mueller and Grams, 2021) were used to design the hydrograph and 

evaluate potential outcomes during the planning process for a potential fall 2022 HFE. The models were also used to illustrate for 

the technical team the relative importance of HFE magnitude and duration (Figure 3). 
21

Figure 3. Predicted changes in sandbar volume for potential HFEs of different magnitude and duration using the Mueller and 

Grams (2021) sandbar volume model. (A) For potential HFEs of both 24-hour and 48-hour duration, magnitude has a strong

control over deposition because it controls potential deposit size by inundating more area. This physical control on bar deposition 

is consistent with observations and modeling results from the 1996 HFE (Hazel and others, 2022). A relatively low-magnitude 

HFE of ~33,100 ft3/s is predicted to be about one-third as effective as a 45,000 ft3/s HFE. (B) Duration is secondary to frequency, 

but also important because time is needed for sand concentrations to increase and for sand to be redistributed within eddies. A 

relatively short-duration 24-hour HFE predicted to be about one-third as effective as a 96-hour HFE. 

While HFEs have resulted in sandbar deposition and net increases in sandbar volume, campsite 

area has remained stable or decreased owing to vegetation expansion, which has been ongoing 

in Marble and Grand Canyons (Sankey and others, 2015; Hadley and others, 2018; Kasprak and 

others, 2018). Vegetation expansion consisted mostly of tamarisk between 2002 and 2009 and 

seep willow between 2009 and 2013 (Durning and others, 2021). Vegetation removal is being 

conducted experimentally by National Park Service personnel at three of the long-term sandbar 

monitoring sites. We will be monitoring the effect of vegetation removal on deposition and 

erosion for those sites. 

Element B.2. Bathymetric and Topographic Mapping for Monitoring Long-term Trends in Sediment 

Storage

Project B.2 addresses the hypothesis that the supply of sand in sandbars, eddies, and on the 

riverbed will be maintained during the 20-year period of the LTEMP EIS, which will include 

sand-enriched HFEs, normal dam operations, and possibly include sustained high releases for 

reservoir equalization. This hypothesis is addressed by repeat measurements of sediment 

storage in sandbars, eddies, and on the riverbed at 3- to 10-year intervals with coupled 

topographic and bathymetric surveys. The measurements of sediment storage change are also 

used to verify and complement the sediment budgets that are estimated based on 

measurements of suspended-sediment concentration as part of Project A. The continuous 

measurements of suspended-sediment concentration made in Project A allow sediment 

budgets to be computed for any time interval of interest, but because uncertainty accumulates, 

budgets computed over long time periods (more than a few years) have large uncertainty 

(Grams and others, 2013; 2019). 
22

In Project B, sediment budgets are computed based on infrequent repeat measurements of 

channel bathymetry. Because uncertainty does not accumulate over time when using this 

method, sediment storage changes over long time periods (many years or decades) can be 

computed accurately and with well-constrained uncertainty.

During FY 2022, we completed processing of data collected in 2019 lower Marble Canyon (River 

Miles (RM) 29 to 61) and eastern Grand Canyon (RM 61 to 87), data collected for Spring 

Disturbance Flow (SDF), and data collected during the 2021 overflight. Data sets from these 

mapping efforts and reports describing the results will be completed in FY 2023. A new channel 

mapping data set was collected in April 2022 for west central Grand Canyon (RM 87-166). This 

effort consisted of 64 topographic surveys, 143 total station setups, and 165 individual sonar 

surveys. Quality control checks on the bathymetric surveys are complete and the data are being 

processed. Processing of this data set will occur during FY 2023 with reporting on this data set 

occurring in the next work plan. 

Element B.3. Control Network and Survey Support

Project Element B.3 provides the geodetic framework needed to enable high-accuracy change 

detection and to ensure that geospatial data collected in Project B and other projects are 

accurately referenced, precisely defined, and can be reliably compared with past and future 

data sets.

In April 2022, the following contributions were made to the control network through the river 

mile (RM) 87-167 channel mapping effort:

• 218 pre-existing network stations were occupied, 

• 64 topographic surveys were performed, 

• 666 repetitious angle shots were added to the network, 

• 401 benchmark/backsight pairs were used, 

• 148 mechanical total stations were set up, measuring 452 repetitious shots, 

• 179 robotic repetitious shots were acquired, 

• 165 sonar projects were collected and georeferenced, and 

• 113 temporary instrument stations were established. 

The CRe control network now includes 2985 points, with 1806 positioned through least-squares 

adjustment of multiple measurements. The network results are consistent with alternate 

processing and adjustment methods (e.g., AUSPOS, OPUS Projects) within < 5 cm at 95% 

confidence, providing reassurances that the base maps we have created and the physical 

changes we measure are both reliable and repeatable.

GCMRC continues to work alongside the National Geodetic Survey to ensure the decades of 

spatial data collected within the Grand Canyon region can be seamlessly combined with future 

data sets. The North American Datum of 1983 (NAD83) will be superseded with the North 

American Terrestrial Reference Frame of 2022 (NATRF2022) this fiscal year. 
23

This migration requires new horizontal and vertical coordinates to be computed, which model 

tectonic plate rotations and will more accurately align with high-resolution satellite data. Intraplate velocities will become integral to each position within the National Spatial Reference 

System and these changes will need to be considered within the context of long-term 

monitoring of the Colorado River ecosystem.

Element B.5. Streamflow and Fine Sediment Modeling

The purpose of Project Element B.5 is to develop models for predicting the concentration and 

transport of silt- and clay-size sediment. This project is proceeding in collaboration with 

personnel from Project A and input from scientists working on Projects E and G. Existing models 

in use by GCMRC and Reclamation focus on predicting sand concentration, sand transport, and 

sandbar deposition and erosion. Although silt and clay typically account for 60% or more of the 

total sediment input and suspended-sediment load on the Colorado River in Grand Canyon, 

very little effort has been directed at modeling this component of the sediment load because 

most of the bed and eddy sandbars are composed of sand-sized sediment. The silt- and claysize sediment, however, strongly affects turbidity and nutrient dynamics, which are increasingly 

recognized as potentially important controls on native and nonnative fish populations (Ward 

and others, 2016). 

In FY 2022, we began developing a new fine sediment (sand, silt, and clay) routing model, which 

includes sediment advection, eddy exchange, exchange with the bed, and storage/release from 

bar deposits. We are using the extensive suspended sediment and water-quality data sets 

collected over the past two decades (Topping and others, 2021) to provide model inputs and 

for validation/calibration. Preliminary model results highlight the importance of eddy exchange 

in accurately capturing the timing and attenuation of fine sediment pulses as they travel 

downstream following tributary inputs. We also find that mud storage and release from 

bed/bar deposits is an important control on turbidity, particularly at relatively low levels of 

turbidity that are nonetheless important for controlling biological resources (e.g., native and 

nonnative fish) and as a driver of primary productivity. This effort will improve our ability to 

predict how dam operations, including high-flow experiments, affect concentrations and 

transport of all sizes of suspended sediment. This work leverages existing monitoring efforts to 

improve predictive modeling capabilities for fine sediment and will not lead to new or 

additional monitoring efforts.

This element was included in the FY 2021-23 TWP as unfunded in the event that other funding 

sources could be found to support the important modeling objectives. Other funding sources 

were found in FY 2022 from the USGS Ecosystems Mission Area. These funds were 

supplemented with unspent TWP funds.
24

References

Butterfield, B.J., Grams, P.E., Durning, L.E., Hazel, J.E., Palmquist, E.C., Ralston, B.E., and Sankey, 

J.B., 2020, Associations between riparian plant morphological guilds and fluvial sediment 

dynamics along the regulated Colorado River in Grand Canyon: River Research and 

Applications, v. 36, no. 3, p. 410-421, https://doi.org/10.1002/rra.3589. 

Durning, L.E., Sankey, J.B., Yackulic, C.B., Grams, P.E., Butterfield, B.J. and Sankey, T.T., 2021, 

Hydrologic and geomorphic effects on riparian plant species occurrence and 

encroachment—Remote sensing of 360 km of the Colorado River in Grand Canyon: 

Ecohydrology, v. 14, no. 8, e2344, https://doi.org/10.1002/eco.2344. 

Grams, P.E., 2019, Sandbar deposition caused by high-flow experiments on the Colorado River 

downstream from Glen Canyon Dam, November 2012 – November 2018: Glen Canyon Dam 

Adaptive Management Program Annual Reporting Meeting, March 12-13, 2019, Phoenix, 

Ariz., https://www.usbr.gov/uc/progact/amp/amwg/2019-03-06-amwg-meeting/20190301-

HFE_Extended_Abstracts-Combined_FINAL.pdf. 

Grams, P.E., Tusso, R.B., and Buscombe, D., 2018, Automated remote cameras for monitoring 

alluvial sandbars on the Colorado River in Grand Canyon, Arizona: U.S. Geological Survey 

Open-File Report 2018-1019, 50 p., https://doi.org/10.3133/ofr20181019. 

Grams, P.E., Topping, D.J., Schmidt, J.C., Hazel, J.E., Jr., and Kaplinski, M.A., 2013, Linking 

morphodynamic response with sediment mass balance on the Colorado River in Marble 

Canyon—Issues of scale, geomorphic setting, and sampling design: Journal of Geophysical 

Research—Earth Surface, v. 118, no. 2, p. 361-381, https://doi.org/10.1002/jgrf.20050. 

Grams, P.E., Buscombe, D., Topping, D.J., Kaplinski, M.A., and Hazel, J.E., Jr., 2019, How many 

measurements are required to construct an accurate sand budget in a large river? Insights 

from analyses of signal and noise. Earth Surface Processes and Landforms, v. 44, no. 1, p. 

160-178, https://doi.org/10.1002/esp.4489.

Hadley, D.R., Grams, P.E., and Kaplinski, M.A., 2018, Quantifying geomorphic and vegetation 

change at sandbar campsites in response to flow regulation and controlled floods, Grand 

Canyon National Park, Arizona: River Research and Applications, v. 34, no. 9, p. 1208-1218, 

https://doi.org/10.1002/rra.3349. 

Hazel, J.E., Jr., Grams, P.E., Schmidt, J.C., and Kaplinski, M., 2010, Sandbar response following 

the 2008 high-flow experiment on the Colorado River in Marble and Grand Canyons: U.S. 

Geological Survey Scientific Investigations Report 2010-5015, p. 52 p., 

http://pubs.usgs.gov/sir/2010/5015. 

Hazel, J.E., Kaplinski, M.A., Hamill, D., Buscombe, D., Mueller, E.R., Ross, R.P., Kohl, K., and 

Grams, P.E., 2022, Multi-decadal sandbar response to flow management downstream from 

a large dam—The Glen Canyon Dam on the Colorado River in Marble and Grand Canyons, 

Arizona: U.S. Geological Survey Professional Paper 1873, prepared in cooperation with 

Northern Arizona University, 104 p., https://doi.org/10.3133/pp1873. 

Kasprak, A., Sankey, J.B., Buscombe, D., Caster, J., East, A.E., and Grams, P.E., 2018, Quantifying 

and forecasting changes in the areal extent of river valley sediment in response to altered 

hydrology and land cover: Progress in Physical Geography: Earth and Environment, v. 42, 

no. 6, p. 739-764, https://doi.org/10.1177/0309133318795846. 
25

Mueller, E.R., Grams, P.E., Hazel, J.E., and Schmidt, J.C., 2018, Variability in eddy sandbar 

dynamics during two decades of controlled flooding of the Colorado River in the Grand 

Canyon: Sedimentary Geology, v. 363, p. 181–199,

https://doi.org/10.1016/j.sedgeo.2017.11.007. 

Mueller, E.R., and Grams, P.E., 2021, A morphodynamic model to evaluate long-term sandbar 

rebuilding using controlled floods in the Grand Canyon: Geophysical Research Letters, v. 48, 

no. 9, e2021GL093007, https://doi.org/10.1029/2021GL093007. 

Sankey, J.B., Ralston, B.E., Grams, P.E., Schmidt, J.C., and Cagney, L.E., 2015, Riparian 

vegetation, Colorado River, and climate—Five decades of spatiotemporal dynamics in the 

Grand Canyon with river regulation: Journal of Geophysical Research: Biogeosciences, v. 

120, no. 8, p. 1532-1547, https://doi.org/10.1002/2015JG002991. 

Topping, D.J., Grams, P.E., Griffiths, R.E., Dean, D.J., Wright, S.A., and Unema, J.A., 2021, Selflimitation of sand storage in a bedrock-canyon river arising from the interaction of flow and 

grain size: Journal of Geophysical Research: Earth Surface, v. 126, no. 5, e2020JF005565, 

https://doi.org/10.1029/2020JF005565. 

Ward, D.L., Morton-Starner, R., and Vaage, B., 2016, Effects of turbidity on predation 

vulnerability of juvenile humpback chub to rainbow trout and brown trout: Journal of Fish 

and Wildlife Management, v. 7, no. 1, p. 205-212, https://doi.org/10.3996/102015-JFWM101. 

Wright, S.A., Topping, D.J., Rubin, D.M., and Melis, T.S., 2010, An approach for modeling 

sediment budgets in supply-limited rivers: Water Resources Research, v. 46, no. 10, p. 1-18,

https://doi.org/10.1029/2009WR008600.

Project B Budget

Burden

12.326%

Budgeted

Amount $382,144 $5,000 $32,000 $353,293 $0 $62,262 $834,699 

Actual

Spent $436,289 $7,555 $48,891 $8,000 $0 $60,974 $561,709 

(Over)/Under

Budget ($54,145) ($2,555) ($16,891) $345,293 $0 $1,288 $272,990 

FY21 Unspent Funds $0 FY22 Unspent Funds $272,990

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated unspent; etc.)

FY22 Comments:

-Overspent Salaries is due to bringing staff from other USGS centers and overtime associated with the Channel Mapping river 

trip that was rescheduled from FY21.

-Overspent Travel & Training is due to field work and the Channel Mapping river trip that was moved from FY21 to FY22 due to 

Covid-19.

-Overspent Operating Expenses is due to necessary Inertial Navigation System equipment rental for the Channel Mapping river 

trip. 

-Underspent funds in Cooperative Agreements is due to personnel working on this project left Northern Arizona University and 

the agreement will not be continued. The work will be accomplished by increasing staff at GCMRC. 

Project B Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
26

Project B Deliverables: Sandbar and Sediment Storage Monitoring and Research

Presentations:

Mueller, E.R., and Grams P.E., 2021, A morphodynamic model to evaluate long-term sandbar 

rebuilding using controlled floods: Glen Canyon Dam Adaptive Management Program

Technical Work Group Meeting, October 2021.

Grams, P.E., 2022, The effects of high-flow experiments and dam releases on sandbar erosion 

and deposition in Marble and Grand canyons: Glen Canyon Dam Adaptive Management 

Program Annual Reporting Meeting, January 2022.

Grams, P.E., 2022, Sediment dynamics in western Grand Canyon during 2021 Spring disturbance 

flow: Glen Canyon Dam Adaptive Management Program Annual Reporting Meeting, January 

2022.

Grams, P.E., 2022, Summary of sediment and sandbar projects—GCMRC Projects A and B, 

LTEMP Goal 7: Glen Canyon Dam Adaptive Management Program Adaptive Management 

Work Group Meeting, February 2022.

Grams, P.E. and Mueller, E.R., 2022, Predicted effects of alternative summer 2022 release 

scenarios on sediment and sandbars: Glen Canyon Dam Adaptive Management Program

Webinar on Glen Canyon Dam Summer 2022 Release Pattern, March 2022.

Grams, P.E., 2022, Multi-decadal sandbar response to flow management downstream from a 

large dam—The Colorado River in Marble and Grand canyons, Arizona: Glen Canyon Dam 

Adaptive Management Program Adaptive Management Work Group Meeting, August 2022.

USGS Reports:

Hazel, J.E., Kaplinski, M.A., Hamill, D., Buscombe, D., Mueller, E.R., Ross, R.P., Kohl, K., and 

Grams, P.E., 2022, Multi-decadal sandbar response to flow management downstream from 

a large dam—The Glen Canyon Dam on the Colorado River in Marble and Grand Canyons, 

Arizona: U.S. Geological Survey Professional Paper 1873, prepared in cooperation with 

Northern Arizona University, 104 p., https://doi.org/10.3133/pp1873. 

Kaplinski, M., Hazel, J.E., Jr., Grams, P.E., Gushue, T.M., Buscombe, D., and Kohl, K., 2022, 

Channel mapping of the Colorado River from Glen Canyon Dam to Lees Ferry in Glen Canyon 

National Recreation Area, Arizona: U.S. Geological Survey Open-File Report 2022-1057, 20 

p., https://doi.org/10.3133/ofr20221057. 

USGS Data Releases:

Kaplinski, M., Hazel, J.E. Jr, Grams, P.E., Gushue, T., Buscombe, D.D., and Kohl, K., 2022, Channel 

mapping Glen Canyon Dam to Lees Ferry in Glen Canyon National Recreation Area, Arizona - 

Data: U.S. Geological Survey data release, https://doi.org/10.5066/P98GFP93. 

Web Applications:

Sandbar Monitoring Data: http://www.gcmrc.gov/sandbar

(https://www.usgs.gov/apps/sandbar/) 
27

Remote Camera Sandbar Photographs: http://www.gcmrc.gov/sandbar

(https://grandcanyon.usgs.gov/gisapps/sandbarphotoviewer/RemoteCameraTimeSeries.ht

ml) 

Grand Canyon River Guides Adopt-a-Beach Photographs: http://www.gcmrc.gov/sandbar

(https://grandcanyon.usgs.gov/gisapps/adopt-a-beach/index.html) 
28

Project C: Riparian Vegetation Monitoring and Research

Goals and Objectives

This project aims to monitor changes to riparian vegetation using field-collected data (C.1), 

develop process-based models of vegetation responses to hydrological regimes through 

controlled experiments (C.2), develop predictive models of vegetation responses to 

hydrological and climate variability through synthesis of previous work across multiple 

hierarchical scales (C.3), and provide monitoring protocols and decision support tools for active 

vegetation management (C.4).

The list of accomplishments and products below is for fiscal year (FY) 2022. Products completed 

during this time frame are included in the “Deliverables” section. Results of both completed 

and on-going work initiated in FY 2022 are described in “Project Elements.”

Project Elements

Element C.1. Ground-based Riparian Vegetation Monitoring

Science Questions

• What is the status (composition and cover) of native and nonnative vascular plant 

species within the riparian zone of the Colorado River from Glen Canyon Dam to the 

historical high-water line of Lake Mead, approximately 240 river miles downstream of

Lees Ferry?

• How do dam operations interact with the physical and biological environment to 

determine vegetation status?

Results

Riparian vegetation monitoring data were collected at the long-term monitoring sandbars 

included in Project B and at additional randomly selected sandbars, debris fans, and channel 

margins in August-October 2022. Between river miles (RM) -15.5 and 240, 94 randomly selected 

sites, and 45 annually sampled long-term sites were sampled. Data from 2022 are currently 

being entered into the riparian vegetation database and error checked. 

Project Lead Emily Palmquist

Principal 

Investigator(s) (PI)

Emily Palmquist, USGS, GCMRC

Brad Butterfield, NAU

Email epalmquist@usgs.gov

Telephone (928) 556-7397
29

Trends in native and nonnative species richness, cover by functional groups and species, and 

frequency of species are reported on a 5-year basis as a separate, stand-alone report, in order 

to thoroughly address methods, interannual variation, uncertainties, management implications, 

and interpretations of trends. 

A summary of the overall status and trends in riparian vegetation composition and cover from 

2014 through 2019 was drafted as a USGS Status and Trends Open-File Report and is currently 

in press. Specific metrics to be reported annually are currently being determined as part of a 

larger, ongoing metrics development project (U.S. Department of the Interior, 2020; FY2021-23 

TWP, Reclamation section C.12). The metrics under consideration are total plant cover, native 

plant richness, and native to nonnative species cover ratio, which are all metrics that can be 

derived from the riparian monitoring program and repeat aerial imagery analysis.

Presence and cover data for a preliminary set of eight plant species were analyzed with 

environmental and biotic variables using monitoring data from 2016 through 2020. An ordinal, 

zero-augmented Bayesian model was developed to simultaneously model presence versus 

cover responses with respect to temperature, hydrology, substrate, site conditions, and their 

interactions with mean annual temperature. 

These preliminary analyses indicate that 1) presence and cover can differ in their controlling 

environmental variables and direction of responses, 2) the timing of daily load-following flows 

plays a significant role in riparian plant presence and cover, with coyote willow (Salix exigua) 

exhibiting reductions in both presence and cover where daily tides are high in the afternoon, 

and 3) higher air temperature changes how plants respond to environmental variables, 

including hydrology. These analyses are ongoing, and the model is being used for analyzing data 

for an additional 32 species.

Element C.2. Determining Hydrological Tolerances and Management Tools for Plant Species of 

Interest

Science Questions:

• How do plant species vary in their adaptations to seasonal variations in base flows 

versus daily fluctuating flows? 

• How can a mechanistic understanding of plant physiological responses to dam 

operations improve vegetation management outcomes? 

Results

We completed analysis of plant responses to the 2021 spring disturbance flows (see Project O 

for further details) that provided unique insights into how riparian plants with different habitat 

preferences and functional strategies respond to short-term flow anomalies. 
30

Specifically, we quantified how multiple metrics of plant water status in tall fescue

(Schedonorus arundinaceus), a hydric grass that grows in near-channel habitats that are 

inundated and exposed by daily fluctuating flows, and arrowweed (Pluchea sericea), a mesic 

shrub that thrives in the zone inundated by HFEs, responded to the low and high flow phases of 

the spring disturbance flows, interpreted in the contexts of both drought and inundation stress.

Among other results, we found unique responses of the two species to low versus high flow 

anomalies (Figure 1), where Schedonorus exhibited stem cavitation risk (drought-induced 

embolism) in response to low flow conditions, while Pluchea tolerated low flow conditions by 

reducing leaf water content and capitalizing on high flow conditions exhibited by increased 

stem water potential. These asymmetric responses to low and high flows provide insights into 

how plants with different habitat preferences and functional strategies respond to flow 

variation and provide predictions about how these and similar species would likely respond to 

longer duration changes to the hydrograph. A manuscript is in review (Butterfield and others, in 

review). 

Figure 1. Physiological responses to the spring disturbance flows. Schedonorus stem water potential decreased during the low 

flow phase, while that of Pluchea increased during the high flow phase, relative to the pre-experiment conditions. Conversely, 

leaf relative water content of Schedonorus increased during the high flow phase, while that of Pluchea decreased during the low 

flow phase. These different responses reflect plant adaptations to variation in drought stress and inundation that can help inform 

predictions of plant responses to HFEs and other types of flow anomalies.

We also conducted a greenhouse experiment to determine how well species’ local hydrological 

niches – specifically the elevations above the CRe channel at which they generally occur – 

correspond with their drought or inundation tolerances. We anticipated that the results could 

tell us the extent to which the current vegetation has been structured by high flow anomalies 

(inundation tolerances) versus low flow anomalies (drought tolerances). We implemented 

drought, control, and flooding treatments and measured stomatal conductance and new root 

growth as indicators of stress responses.
31

Among other results, we found (1) a strong relationship between species hydrological niche 

(elevation above the channel in the CRe and inhibition of root growth under flood conditions 

(Figure 2) and (2) increasingly divergent stomatal conductance responses to drought with 

increasing elevation above the channel (not shown). 

These results suggest that current species distributions along hydrological gradients in the CRe 

have been structured by the amplitude of high flow anomalies (HFEs and peak load following 

flows) and are likely to be particularly sensitive to future inundating events, but also that the 

magnitude and duration of low flow anomalies are likely to differentially affect species in 

predictable ways based upon their physiological and growth responses to our experimental 

treatments. These results are included in a manuscript nearing submission for peer review and 

will be presented at the Annual Reporting Meeting in January 2023.

Figure 2. Experimental setup and selected results from the greenhouse experiment. Experimental treatments were established 

at the Northern Arizona University (NAU) Research Greenhouse Complex, where bins with recirculating pumps were assigned to 

one of three water treatments: drought, control or flood. On the right is one selected result, demonstrating that plants that 

naturally grow at higher elevations above the channel in the CRe experience greater root growth inhibition when subjected to 

flooding in the greenhouse. Species are: EQFE – Equisetum x ferrissii, PHAU – Phragmite australis, SAEX – Salix exigua, 

BAEM – Baccharis emoryi, TARA – Tamarix ramossisima x chinensis, PLSE – Pluchea sericea, PRGL – Prosopis glandulosa, 

ACGR – Acacia greggii. 

Element C.3. Predictive Models and Synthesis

Science Questions

• What are the predicted changes to CRe vegetation status in the future under current

and alternative LTEMP dam operations?

• What are the knowledge gaps in CRe plant ecology, and how can we fill them with 

existing data sources?
32

Results

We published a peer-reviewed manuscript (Butterfield, Palmquist and Yackulic, 2022) on the 

effects of streamflow seasonality on the composition and diversity of riparian vegetation within 

the CRe. Specifically, we developed empirical models of plant species habitat requirements with 

respect to their suitable hydroclimate – the temperature, precipitation, and vapor pressure 

deficit during the lowest and highest streamflow months – and projected those models under 

different simulated seasonal timings of low and high streamflow months in the CRe. This study 

leveraged extensive open-source data, including millions of plant occurrence records from 

across the US, climate data, and a novel application of the National Hydrography Database.

Among other results, we found that (1) total species richness is predicted to be highest with 

summer high flows, (2) native-to-nonnative ratio is predicted to be highest with winter low 

flows, and (3) species that have increased in cover over recent decades, such as arrowweed and 

seepwillows (Baccharis sp.) exhibit particularly high habitat suitability when high flows 

correspond with high temperatures (summer). Along with other results, this study 

demonstrates that the current composition of CRe riparian vegetation has been shaped by the 

seasonal timing of low and high flows out of Glen Canyon Dam and provides predictions for 

how that vegetation could change with seasonal alterations to the hydrograph.

Figure 3. Selected results from the “hydroclimate” study published in Butterfield and others (2022). The panel on the left 

demonstrates the increase in predicted species richness with summer high streamflows, while the the panel on the right 

demonstrates the increase in native dominance with winter low streamflows. The triangles represent the months of high and low 

streamflow of the current hydrograph.
33

Element C.4. Vegetation Management Decision Support

Science Questions

• How can GCMRC monitoring and research be leveraged to assist with experimental

vegetation management plans and implementation by the National Park Service (NPS) 

and Tribes?

Results

As in years past, we participated in planning meetings for NPS-led non-flow experimental 

vegetation treatments (U.S. Department of the Interior, 2020; FY 2021-23 TWP, Reclamation 

sections C.7 and C.8) to consult on ongoing and new work sites. Five campsites and a Glen 

Canyon National Recreation Area restoration site that are undergoing annual vegetation 

removal and maintenance are monitored annually as part of the collaborative GCMRC annual 

sandbar monitoring, which includes topographic, campsite (Project B) and vegetation (Project 

C) surveys: -6.6 RM, Basalt Camp, Upper Clear Creek Camp, Granite Camp, 122 Mile Camp, and 

202 Mile Camp. A manuscript describing the manipulative greenhouse experiment testing the 

influence of inundation on arrowweed was published in (Palmquist and others, 2022). This work 

indicated that individuals from different locations in the CRe have different phenotypes, that 

plant growth was strongly decreased with inundation, and that arrowweed responds to the 

environment in unique ways when compared to riparian trees. The information gained from 

this study can help understand arrowweed growth and expansion in the CRe, a key species in 

campsite encroachment and vegetation removals.

Additionally, we participated in the USGS/Tuba City Partnership Summer Camp for native youth 

by teaching students about riparian ecosystems at Lees Ferry and upstream. Topics covered 

included identifying plants, appropriate scientific collection of plants, plant physiology, and 

riparian restoration. The NPS/Grand Canyon Wildlands cooperative restoration project at Paria 

Beach was used as an illustration of restoration concepts, and a representative from Grand 

Canyon Wildlands also participated.

References

Butterfield, B.J. and Palmquist, E.C., in review, Divergent physiological responses of hydric and 

mesic riparian plant species to a Colorado River experimental flow: Plant Ecology.

Butterfield, B.J., Palmquist, E.C., and Yackulic, C.B., 2022, The hydroclimate niche—A tool for 

predicting and managing riparian plant community responses to streamflow seasonality: 

River Research and Applications, v. 39, no. 1, p. 84-94, https://doi.org/10.1002/rra.4067. 

Palmquist, E.C., Ogle, K., Whitham, T.G., Allan, G.J., Shafroth, P.B., and Butterfield, B.J., 2022, 

Provenance, genotype, and flooding influence growth and resource acquisition 

characteristics in a clonal, riparian shrub: American Journal of Botany, online, 

https://doi.org/10.1002/ajb2.16115. 
34

U.S. Department of the Interior, 2020, Glen Canyon Dam Adaptive Management Program 

Triennial Budget and Work Plan—Fiscal years 2021-2023—Final approved by the Secretary 

of the Interior—December 2, 2020: Flagstaff, Ariz., U.S. Geological Survey, Grand Canyon 

Monitoring and Research Center, and Salt Lake City, Utah, Bureau of Reclamation, Upper 

Colorado Region, 384 p.,

http://gcdamp.com/images_gcdamp_com/5/5d/GCMRC_TWP2021-

23_December2_2020_ApprovedBySecretary.pdf. 

Project C Budget

Project C Deliverables: Riparian Vegetation Monitoring and Research

Presentations:

Butterfield, B.J. and Palmquist, E.C., 2022, Riparian vegetation monitoring and modeling—

presentation: Glen Canyon Dam Adaptive Management Program Annual Reporting Meeting, 

January 12, 2022.

Kennedy, T., Deemer, B., Lytle, D., Grams, P., Sankey, J., Butterfield, B.J., Dibble, K., Bair, L., and 

Tusso, R., 2022, Disturbance Flow Panel Session—presentation: Glen Canyon Dam Adaptive 

Management Program Annual Reporting Meeting, January 12, 2022.

Pilkington, L., Stevens, L., Burke, K., Butterfield, B.J., Palmquist, E., and Sankey, J., 2022, Riparian 

vegetation science & management—webinar presentation: Glen Canyon Dam Adaptive 

Management Program Adaptive Management Work Group Meeting, February 9-10, 2022, 

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

Research Center, https://www.usbr.gov/uc/progact/amp/amwg.html. 

Palmquist, E., Ogle, K., Butterfield, B.J., Whitham, T., Shafroth, P., and Allan, G., 2022, 

Provenance of a riparian shrub changes traits but not flood response under a common 

climatic setting: River's Edge West 20th Anniversary Riparian Restoration Conference, 

February 23-25, 2022, Grand Junction, CO.

Burden

12.326%

Budgeted

Amount $134,307 $3,940 $1,565 $107,337 $0 $20,453 $267,602 

Actual

Spent $133,693 $2,129 $1,102 $109,097 $0 $20,150 $266,170 

(Over)/Under

Budget $614 $1,811 $464 ($1,760) $0 $303 $1,432 

FY21 Unspent Funds $0 FY22 Unspent Funds $1,432

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated unspent; etc.)

FY22 Comments:

-Underspent Salaries is due to technician turnover on this project.

-Underspent Travel & Training were to compensate for increased botanist costs. A local conference was attended instead of a 

national conference.

-Overspent funds in Cooperative Agreements was due to increased costs for hiring botanists through NPS.

Project C Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
35

Palmquist, E.C., 2022, Goal 11: Riparian Vegetation Draft Metrics—presentation: Glen Canyon 

Dam Adaptive Management Program Technical Work Group Meeting, April 13, 2022.

Palmquist, E.C., Ogle, K., and Butterfield, B.J., 2022, Riparian plant presence and abundance are 

differentially controlled by hydrology and temperature along a regulated, dryland river—

presentation: 16th Biennial Conference of Science & Management on the Colorado Plateau 

and Southwest Region, September 12-15, 2022, Flagstaff, AZ.

Butterfield, B.J., Palmquist, E.C., and Yackulic, C.B., 2022, The hydroclimatic niche—A tool for 

predicting and managing riparian plant community responses to streamflow seasonality—

presentation: 16th Biennial Conference of Science & Management on the Colorado Plateau 

& Southwest Region, September 12-15, 2022, Flagstaff, AZ.

Journal Articles:

Butterfield, B.J., Palmquist, E.C., and Yackulic, C.B., 2022, The hydroclimate niche—A tool for 

predicting and managing riparian plant community responses to streamflow seasonality: 

River Research and Applications, v. 39, no. 1, p. 84-94, https://doi.org/10.1002/rra.4067. 

Samuels-Crow, K., Ogle, K., and Palmquist, E.C., 2022, What drought means for southwestern 

landscapes: Boatman's Quarterly Review, v. 35, no. 1, p. 16-19. (Article not available online)

USGS Data Releases:

Palmquist, E.C., Ralston, B.E., Sarr, D., Merritt, D.M., Shafroth, P.B., Scott, J.A., 2017, 

Southwestern riparian plant trait matrix, Colorado River, Grand Canyon, Arizona (ver. 2.0, 

January 2022): U.S. Geological Survey data release, https://doi.org/10.5066/P974VCDK. 

Palmquist, E.C., Butterfield, B.J., and Ralston, B.E., 2022, Riparian vegetation data downstream 

of Glen Canyon Dam in Glen Canyon National Recreation Area and Grand Canyon National 

Park, AZ, from 2014 to 2019: U.S. Geological Survey data release, 

https://doi.org/10.5066/P9KEHY2S. 
36

Project D: Geomorphic Effects of Dam Operations and

Vegetation Management for Archaeological Sites

Goals and Objectives

The LTEMP goal for Archaeological and Cultural Resourcesaintain the integrity of potentially 

affected National Register of Historic Places (NRHP)-eligible or listed historic properties in place, 

where possible, with preservation methods employed on a site-specific basis.

Project D quantifies changes in the physical condition of river corridor archaeological sites in 

Grand Canyon as a function of: i) dam operations, ii) vegetation management, and iii) natural 

processes. While the dam and its operation are not the only sources of change affecting the 

CRe and associated archaeological sites, this project focuses on studying and monitoring dam 

effects, in keeping with the mandates of the Grand Canyon Protection Act (GCPA) and 

consistent with the monitoring plan developed in 2015 and Reclamation’s 2017 Historic 

Preservation Plan. The ongoing and experimental dam operations and vegetation management 

actions of interest are those that are undertaken under the Record of Decision for the Glen 

Canyon Dam Long-Term Experimental and Management Plan final Environmental Impact 

Statement (LTEMP ROD; U.S. Department of the Interior, 2016b) through 2036.

Here, we report on progress made during FY 2022 on monitoring the effects of dam operations 

and vegetation management at archaeological sites under the different elements of this 

project. The project consists of four elements, but we only report on the three elements (D.1, 

D.2, and D.3) that were funded in FY 2022.

Project Elements

Element D.1. Geomorphic Effects of Dam Operations and Vegetation Management 

Science Questions/Hypotheses Addressed

• Do HFEs increase the resupply of river sand to archaeological sites in the river corridor

and offset erosion, thus achieving the LTEMP resource goal of preservation in place?

• Does removal of riparian vegetation located between HFE-sediment supplied sandbars 

and archaeologic sites increase the resupply of sediment to archaeological sites and 

thus increase the probability of preservation in place and help achieve the LTEMP 

resource goal?

Project Lead Joel Sankey

Principal 

Investigator(s) (PI)

Joel Sankey, USGS, GCMRC

Helen Fairley, USGS, GCMRC

Email jsankey@usgs.gov

Telephone (928) 556-7289
37

• Do vegetation and biological soil crust cover within archaeological sites that are not 

resupplied with sediment from HFEs reduce erosion and therefore increase the 

probability of achieving the LTEMP resource goal of preservation in place?

Results

Figure 1 summarizes methods and site class definitions for the aeolian classification system, and 

Figure 2 summarizes the results of using that system to monitor long-term changes at 

archaeological sites. Figure 2 shows that river-sourced aeolian sand supply has decreased since 

1973 for nearly all archaeological sites, making most sites more erosion-prone. Specifically, the 

number of archaeological sites classified as Type 1 because they have the highest likelihood to 

receive wind-blown sand supply from fluvial sandbars, decreased over each monitored time 

step, from 98 in 1973 to only four in 2021–22 (Figure 2). In 2021–22 there are an additional 

seven Type 1VR sites that have maintained the Type 1 site characteristics owing to site-specific 

vegetation management efforts implemented between 2019 and 2022 by the National Park 

Service (Pilkington and others., 2022); without the vegetation management work these seven

sites would likely be classified as Type 2 or 3. 

Most of the sites that were Type 1 in 1973 transitioned over time to Type 2 or 3 sites, primarily 

due to the expansion of riparian vegetation onto subaerial sandbars throughout the river 

ecosystem. Riparian vegetation can either create a barrier to aeolian sand transport from 

sandbars to archaeological sites in the case of Type 2a and Type 2c sites, or it can completely 

cover the subaerial sandbar deposit such that there is no longer a source area for aeolian sand 

supply thus resulting in a site being classified as Type 3 (East and others, 2016). Thus, many 

sites that were classified prior to 2021–22 as one of the three subcategories of Type 2 sites 

owing to the presence of a riparian and/or topographic barrier to aeolian sand transport, later 

transitioned to Type 3 sites owing to continued vegetation expansion (Figure 2). The number of 

sites classified as Type 3 increased from 27 in 1973 to 148 in 2021–22 primarily due to these 

vegetation expansion processes. The sites classified as Type 2AVR (3), 2bVR (3), and 2cVR (2) in 

2021–22 would instead currently have the characteristics of Type 3 sites if not for site-specific 

vegetation management efforts implemented between 2019 and 2022 by the National Park 

Service (Pilkington and others, 2022). 
38

Figure 1. Overview of the aeolian classification system and site class definitions (adapted from East and others, 2016; 2017). 
39

Figure 2. Diagram of aeolian class changes over time for 362 archaeological sites in the Colorado River corridor, Grand Canyon 

National Park. See Figure 1 for definition of site class types (preliminary results, do not cite). 

Figure 3 summarizes methods and site class definitions for the drainage classification system, 

and Figure 4 summarizes the results of using that system to monitor long-term changes at 

archaeological sites. Figure 4 shows that the proportion of sites eroding by gully processes has 

increased since 2000. Specifically, the proportion of sites without drainages (e.g., gullies or 

arroyos) has decreased from 2000 to 2021–22 and the proportion of sites with drainages has 

increased during that time, indicating an overall increase in sites affected by gullying processes

(Figure 4). For example, from 2016–17 to 2021–22, sixteen Type D1 sites developed drainages. 

A small number of sites transitioned from having terrace (Type D2) or river-based (Type D4) 

drainages in 2000 to not having drainages in 2016–17 owing to fluvial or aeolian sediment 

backfilling of the drainages (gully annealing, sensu Sankey and Draut, 2014). However, the 

majority of changes in site classifications indicate the progressive development of new 

drainages and the downcutting of existing drainages to lower base levels (e.g., terrace to sidecanyon or river), indicating increasing erosion and greater future erosion potential for the 

archaeological sites. As of 2021–22, 41 sites have side-canyon based drainages and 98 have 

river-based drainages (Figure 4); these sites are effectively at the evolutionary endpoint of 

drainage development because they are graded to the lowest possible base level for their 

respective locations. In 2021–22, 117 sites do not have drainages (Figure 2) and these sites may 

or may not be vulnerable to the development of new drainages in the future, depending on the 

specific geomorphic setting. However, 106 sites in 2021–22 have terrace-based drainages that 

could downcut and become integrated with the base-level of the river in the future; Type D2 

sites represent the intermediary stage of drainage development in the system. 
40

Figure 3. Overview of the drainage classification system and site class definitions (adapted from East and others, 2016; 2017). 
41

Figure 4. Diagram of drainage class changes, based on field assessments of archaeological sites’ geomorphic context in 2000, 

2016–17, and 2021–22. See Figure 3 for definition of site class types (preliminary results, please do not cite). 

Figure 5 summarizes results of topographic changes at a sample of the population of 

archaeological sites, determined with lidar remote sensing for the decade from 2010 to 2020 

(Caster and others, 2022). Sites that underwent net erosion during this time frame occur in 

each of the observed combinations of site classifications. Specifically, one of the five Type 1 

sites, two of the four Type 2 sites, and two of the three Type 3 sites monitored with lidar 

underwent significant erosion, as did the one Type 4 site that was monitored. Previous work 

with topographic change detection from lidar remote sensing has shown that many sites have 

eroded at times during the decade, but that those sites that have aggraded have tended to be 

located adjacent to and downwind of river sandbars that are periodically resupplied with sand 

by HFEs and which, in turn, provide a consistent source of wind-blown river sediment supply to 

downwind archaeological sites (Collins and others, 2016; East and others, 2016; Sankey and 

others, 2018b).
42

Figure 5. Topographic changes for select sites by classification (Caster and others, 2022). 

Element D.2. Monitoring Landscape-scale Ecosystem Change with Repeat Photography

Science Questions/Hypotheses Addressed

• How has riparian vegetation encroachment since dam closure affected the availability of

open sand source areas that formerly served to cover and protect archaeological sites in

the CRe?

• Does pre-dam riparian vegetation cover within the old high-water zone vary through 

time? Specifically, do historical photos taken during the pre-dam period during drought 

periods characterized by lower annual flows show more riparian cover compared with 

photographs taken during pre-dam periods characterized by wetter conditions and 

higher average annual flows? 

• How has the composition and density of riparian vegetation cover changed during the 

50+ years since dam closure?

• Are patterns of vegetation encroachment evident in the historical photo record, and if

so, are they indicative of natural successional processes or are they more reflective of

changes in dam-controlled flow regimes?
43

Results

In FY 2022, we continued matching historical photographs with identical current views to 

document changes in riparian vegetation and geomorphic conditions, including changes to 

open sand areas that serve as source areas for aeolian sand, plus associated dune fields and 

shorelines. As in previous years, this photo-matching effort was conducted with the assistance 

of two unpaid volunteers, Dr. Michael Scott, a retired USGS riparian ecologist, and Mr. Alan 

Fairley, an experienced amateur photographer. 

In 2022, we matched a total of 80 historical photographs. As in 2021, we focused primarily on 

matching color slide images of campsites originally photographed in 1973 (n=72) as part of the 

NPS-sponsored Borden-Weeden campsite carrying capacity study (Borden and others, 1975; 

Weeden and others, 1975). In addition, we matched a few photographs taken by E.C. La Rue in 

1923 (n=3) and by Robert Brewster Stanton in 1889-1890 (n=5). 

As noted in the 2021 Annual Report, the 1973 images are particularly useful to match as they 

show the condition of campsites ten years after Glen Canyon Dam began regulating flows, 

when effects from dam operations on sediment and vegetation were already becoming evident 

but before substantial transformation of the riparian zone had occurred (Figure 6). Many of the 

campsites available in 1973 are still used by boaters today, despite sediment loss from 

fluctuating flows, hillslope runoff and gullying, lack of sediment replenishment, and riparian 

vegetation encroachment (Figure 6a-b); however, many other camps are no longer usable 

today due to significant vegetation encroachment and sediment loss (Figure 6c-d). Regardless 

of whether camps remain habitable or not, vegetation encroachment and the reduction of 

open sand areas is a common theme in all the matched images.

As in the past, the collection of matched images was accompanied by a detailed recording of 

the riparian vegetation visible within the photograph viewshed. The vegetation inventory is 

segregated into several “bins”: 1) new low water zone (ca. 8000-25,000 ft3

/s), 2) new highwater 

zone (ca. 25,000-45,000 ft3/s), old highwater zone (45,000-120,000 ft3/s), and the historical

highwater zone (> 120,000 ft3/s). These bins correspond to the inundation zones previously 

defined by Sankey and others (2015), as follows: Bin 1 = Zone 1, Bin 2 = Zones 2 and 3, Bin 3 = 

Zone 4 (up to 97,000 ft3/s), and Bin 4 = ~Zone 5 (Bin 4 includes everything above 120,000 ft3/s

whereas Zone 5 is defined by Sankey and others, 2015 as the area between 97,000 and 210,000 

ft3/s). In 2022, we conducted some preliminary exploratory analysis of the vegetation data to 

examine the distribution of species occurrence by inundation zone, along with changes in the 

composition of riparian plant communities within each zone (Figure 7). 

 
44

 

Figure 6. Two examples of campsites photographed by Borden-Weeden in July 1973 (top images, 6a left, 6c right) compared to 

their current condition (bottom images, 6b left, 6d right) in May 2022. Left photo match (6a-b) taken at RM 20.0, left bank, looking 

upstream. This place is still used as a campsite today, despite significant loss of open sand area from wind deflation, debris 

flows, vegetation growth, and runoff erosion. Right photo match (6c-d) at RM 122.4., left bank, looking across the river. This 

camp is no longer used by river runners due to significant vegetation encroachment. 1973 photographs (top images) taken by 

unnamed members of the Borden-Weeden study; 2022 photographs (bottom images) by A.H. Fairley, (6bt) April 29, 2022, and 

(6d) May 6, 2022. 
45

Figure 7. Ordination of recorded species by riparian zone. Note the distinctive vegetation assemblage growing in Zone 1, 

immediately adjacent to the river, compared to the species found in Zones 2-5 (farther from the river). Preliminary data, please 

do not cite.

Element D.3. Cultural Program History

Science Questions/Hypotheses Addressed

• How have the previous three decades of research and monitoring informed current 

preservation strategies and NHPA compliance activities in the CRe?

• How have multi-cultural perspectives informed development of the cultural program of

the GCDAMP since its inception 25 years ago?

Results

In FY 2022, we continued to make progress on compiling a history of the GCDAMP cultural 

program. This year we were fortunate to have the assistance of a Native American student from 

Northern Arizona University (NAU), Brooke Damon, who served as an intern with GCMRC for 

ten weeks during the summer. Due to the small amount of funding budgeted for this element 

and because of continuing restrictions imposed by the Covid-19 pandemic, the FY 2022 effort 

focused exclusively on archival research conducted online. A comprehensive bibliography of 

relevant cultural and Tribal presentations and reports from the past 25 years of AMWG 

meetings was compiled as part of this ongoing effort in FY 2022. We are grateful to the Institute 

for Tribal Environmental Professionals for providing financial support for the student intern.
46

References

Borden, Y.F. and Weeden, H.A., 1975, Grand Canyon National Park campsite inventory—

Progress report no. 3: Grand Canyon, Ariz., submitted by H.A. Weeden and others to 

National Park Service, T.W. Sudia, in accordance with contract no. CX0001-3-0061. (Copy on 

file, Grand Canyon National Park Museum Collections Archives, Grand Canyon, Arizona.) 

Boyer, D.E. and Webb, R.H., 2007, Damming Grand Canyon—The 1923 USGS Colorado River 

Expedition: Logan, Utah State University Press, 289 p.

Bureau of Reclamation, 2018, Historic preservation plan for the Glen Canyon Dam operations 

and non-flow actions identified in the Long-Term Experimental and Management Plan 

Environmental Impact Statement and Record of Decision: Salt Lake City, Utah, U.S. 

Department of the Interior, Bureau of Reclamation, Upper Colorado Region, 247 p., 

https://gcdamp.com/images_gcdamp_com/8/86/2018_LTEMP_HPP.pdf. 

Caster, J., Sankey, J.B., Fairley, H., and Kasprak, A., 2022, Terrestrial lidar monitoring of the 

effects of Glen Canyon Dam operations on the geomorphic condition of archaeological sites 

in Grand Canyon National Park, 2010–2020: U.S. Geological Survey Open-File Report 2022–

1097, 100 p., https://doi.org/10.3133/ofr20221097.

Caster, J.J., Sankey, J.B., and Fairley, H., 2018, Meteorological data for selected sites along the 

Colorado River corridor, Arizona, 2014-2015: U.S. Geological Survey data release, 

https://doi.org/10.5066/F7DZ0771.

Caster, J., and Sankey, J.B., 2016, Variability in rainfall at monitoring stations and derivation of a 

long-term rainfall intensity record in the Grand Canyon region, Arizona, USA: U.S. Geological 

Survey Scientific Investigations Report 2016–5012, 38 p., 

http://dx.doi.org/10.3133/sir20165012. 

Caster, J., Dealy, T., Andrews, T., Fairley, H., Draut, A., and Sankey, J., 2014, Meteorological data 

for selected sites along the Colorado River corridor, Arizona, 2011–13: U.S. Geological 

Survey Open-File Report 2014-1247, 56 p., https://dx.doi.org/10.3133/ofr20141247. 

Caster, J.J., Sankey, J.B., and Fairley, H., 2018, Meteorological data for selected sites along the 

Colorado River corridor, Arizona, 2014-2015: U.S. Geological Survey data release, 

https://doi.org/10.5066/F7DZ0771. 

Collins, B.D., Bedford, D.R., Corbett, S.C., Cronkite-Ratcliff, C., and Fairley, H.C., 2016, Relations 

between rainfall–runoff-induced erosion and aeolian deposition at archaeological sites in a 

semi-arid dam-controlled river corridor: Earth Surface Processes and Landforms, v. 41, p. 

899–917, http://dx.doi.org/10.1002/esp.3874. 

Collins, B.D., Brown, K.B., and Fairley, H.C., 2008, Evaluation of terrestrial lidar for monitoring 

geomorphic change at archaeological sites in Grand Canyon National Park, Arizona: U.S. 

Geological Survey Open-File Report 2008-1384, 60 p., https://pubs.usgs.gov/of/2008/1384/. 

Collins, B.D., Corbett, S.C., Sankey, J.B., and Fairley, H.C., 2014, High-resolution topography and 

geomorphology of select archeological sites in Glen Canyon National Recreation Area, 

Arizona: U.S. Geological Survey Scientific Investigations Report 2014-5126, 31 p., 

https://doi.org/10.3133/sir20145126. 
47

Collins, B.D., Minasian, D., and Kayen, R., 2009, Topographic change detection at select 

archaeological sites in Grand Canyon National Park, Arizona, 2006-2007: U.S. Geological 

Survey Scientific Investigations Report 2009-5116, 97 p., 

https://pubs.usgs.gov/sir/2009/5116/. 

Collins, B.D., Corbett, S.C., Fairley, H.C., Minasian, D., Kayen, R., Dealy, T.P., and Bedford, D.R., 

2012, Topographic change detection at select archeological sites in Grand Canyon National 

Park, Arizona, 2007–2010: U.S. Geological Survey Scientific Investigations Report 2012-

5133, 77 p., https://pubs.usgs.gov/sir/2012/5133/. 

Draut, A.E., 2012, Effects of river regulation on aeolian landscapes, Colorado River, 

southwestern USA: Journal of Geophysical Research—Earth Surface, v. 117, no. F2, p. 1-22, 

https://doi.org/10.1029/2011JF002329. 

East, A.E., Sankey, J.B., Fairley, H.C., Caster, J.J., and Kasprak, A., 2017, Modern landscape 

processes affecting archaeological sites along the Colorado River corridor downstream of 

Glen Canyon Dam, Glen Canyon National Recreation Area, Arizona: U.S. Geological Survey 

Scientific Investigations Report 2017–5082, 22 p., https://doi.org/10.3133/sir20175082. 

East, A.E., Collins, B.D., Sankey, J.B., Corbett, S.C., Fairley, H.C., and Caster, J.J., 2016, Conditions 

and processes affecting sand resources at archeological sites in the Colorado River corridor 

below Glen Canyon Dam, Arizona: U.S. Geological Survey Professional Paper 1825, 104 p., 

https://doi.org/10.3133/pp1825. 

Kasprak, A., Caster, J., Bangen, S.G., and Sankey, J.B., 2017, Geomorphic process from 

topographic form—Automating the interpretation of repeat survey data in river valleys: v. 

42, no. 12, p. 1872-1883, https://doi.org/10.1002/esp.4143. 

Kasprak, A., Sankey, J.B., Buscombe, D., Caster, J., East, A.E., and Grams, P.E., 2018, Quantifying 

and forecasting changes in the areal extent of river valley sediment in response to altered 

hydrology and land cover: Progress in Physical Geography: Earth and Environment, v. 42, 

no. 6, p. 739-764, https://doi.org/10.1177/0309133318795846. 

Pilkington, L., Sankey, J.B., Boughter, D., Preston, T., Prophet, C.C., 2022., Parks look for ways to 

alleviate Glen Canyon Dam’s dramatic downstream impacts: Park Science Magazine, 

National Park Service, Glen Canyon National Recreation Area, Grand Canyon National Park, 

v. 36, no. 1, Summer 2022, https://www.nps.gov/articles/000/parks-look-for-ways-toalleviate-glen-canyon-dams-downstream-impacts.htm. 

Sankey, J.B., and Draut, A.E., 2014, Gully annealing by aeolian sediment—Field and remotesensing investigation of aeolian-hillslope-fluvial interactions, Colorado River corridor, 

Arizona, USA: Geomorphology, v. 220, p. 68-80, 

https://doi.org/10.1016/j.geomorph.2014.05.028. 

Sankey, J.B., Fairley, H. C., Caster, J.J., and East, A.E., 2016, Draft plan for monitoring 

archaeological sites in Glen and Grand Canyon: Unpublished report submitted to the U.S. 

Bureau of Reclamation, January 15, 2016.

Sankey, J.B., Kasprak, A., Caster, J.J., East, A.E., and Fairley, H., 2018a, The response of sourcebordering aeolian dunefields to sediment-supply changes 1—Effects of wind variability and 

river-valley morphodynamics: Aeolian Research, v. 32, p. 228-245, 

https://doi.org/10.1016/j.aeolia.2018.02.005. 
48

Sankey, J.B., Caster, J.J., Kasprak, A., and East, A.E., 2018b, The response of source-bordering 

aeolian dunefields to sediment-supply changes 2—Controlled floods of the Colorado River 

in Grand Canyon, Arizona, USA: Aeolian Research, v. 32, p. 154-169, 

https://doi.org/10.1016/j.aeolia.2018.02.004. 

Sankey, J.B., Caster, J., Kasprak, A. and Fairley, H., 2022, The influence of drying on the aeolian 

transport of river-sourced sand: Journal of Geophysical Research: Earth Surface, v. 127, no. 

12, e2022JF006816, p. 1-24, https://doi.org/10.1029/2022JF006816.

Sankey, J.B., Ralston, B.E., Grams, P.E., Schmidt, J.C. and Cagney, L.E., 2015, Riparian vegetation, 

Colorado River, and climate—Five decades of spatiotemporal dynamics in the Grand Canyon 

with river regulation: Journal of Geophysical Research: Biogeosciences, v. 120, no. 8, p. 

1532-1547, https://doi.org/10.1002/2015JG002991.

Weeden, H., Borden, F., Turner, B., Thompson, O.N., Strauss, C., and Johnson, R.R., 1975, Grand 

Canyon National Park campsite inventory—unpublished Colorado River research report: 

University Park, Pennsylvania State University, prepared for the National Park Service, 72 p. 

U.S. Department of Interior, 2016a, Glen Canyon Dam Long-Term Experimental and 

Management Plan Final Environmental Impact Statement (LTEMP FEIS): U.S. Department of 

the Interior, Bureau of Reclamation, Upper Colorado Region, National Park Service, 

Intermountain Region, online, http://ltempeis.anl.gov/documents/final-eis/. 

U.S. Department of Interior, 2016b, Record of Decision for the Glen Canyon Dam Long-Term 

Experimental and Management Plan Final Environmental Impact Statement (LTEMP ROD): 

Salt Lake City, Utah, U.S. Department of the Interior, Bureau of Reclamation, Upper 

Colorado Region, National Park Service, Intermountain Region, 196 p., 

http://ltempeis.anl.gov/documents/docs/LTEMP_ROD.pdf. 

Project D Budget

Burden

12.326%

Budgeted

Amount $214,084 $10,600 $2,806 $0 $0 $28,040 $255,530 

Actual

Spent $208,980 $4,351 $14,417 $0 $0 $28,072 $255,820 

(Over)/Under

Budget $5,104 $6,249 ($11,611) $0 $0 ($32) ($290)

FY21 Unspent Funds $0 FY22 Unspent Funds ($290)

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

- Underspent Salaries is due to staff turnover at the end of the FY.

- Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Overspent amount in Operating Expenses was to cover required instrument calibration. 

Project D Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
49

Project D Deliverables: Geomorphic Effects of Dam Operations and Vegetation 

Management for Archaeological Sites

Presentations:

Fairley, H.C., Scott, M., and Fairley, A.H., 2022, Assessing 50 years of change in riparian 

condition along the Colorado River in Grand Canyon, Arizona—presentation: 16th Biennial 

Conference on Science and Management, Flagstaff, AZ, September 15, 2022. 

Sankey, J.B., East, A., Fairley, H.C., Dierker, J., Brennan, E., Bransky, N., 2022, Risk of erosion of 

archaeological sites along the Colorado River in Grand Canyon owing to long term 

operations of Glen Canyon Dam—presentation: 16th Biennial Conference on Science and 

Management, Flagstaff, AZ, September 15, 2022. 

Papers and Reports:

Caster, J., Sankey, J.B., Fairley, H., and Kasprak, A., 2022, Terrestrial lidar monitoring of the 

effects of Glen Canyon Dam operations on the geomorphic condition of archaeological sites 

in Grand Canyon National Park, 2010–2020: U.S. Geological Survey Open-File Report 2022–

1097, 100 p., https://doi.org/10.3133/ofr20221097. 

Pilkington, L., Sankey, J.B., Boughter, D., Preston, T., Prophet, C.C., 2022, Parks look for ways to 

alleviate Glen Canyon Dam’s dramatic downstream impacts: Park Science Magazine, 

National Park Service, Glen Canyon National Recreation Area, Grand Canyon National Park, 

v. 36, no. 1, Summer 2022, https://www.nps.gov/articles/000/parks-look-for-ways-toalleviate-glen-canyon-dams-downstream-impacts.htm. 

Sankey, J.B., Caster, J., Kasprak, A. and Fairley, H., 2022, The influence of drying on the aeolian 

transport of river-sourced sand: Journal of Geophysical Research: Earth Surface, v. 127, no. 

12, e2022JF006816, p. 1-24, https://doi.org/10.1029/2022JF006816. 
50

Project E: Controls on Ecosystem Productivity: Nutrients, Flow 

and Temperature

Goals and Objectives

Aquatic primary production is an important energy source for riverine food webs, converting 

sunlight, carbon dioxide, and water into simple carbohydrates via photosynthesis. In the 

Colorado River downriver of Glen Canyon Dam, fish are food limited (Cross and others, 2011) 

and energy (carbon) produced within the river is a preferred macroinvertebrate food source 

relative to energy from tributaries and riparian inputs (Wellard Kelly and others, 2013). This 

project aims to disentangle the drivers of riverine primary production and identify their link 

back to fish production. We approach this by combining highly resolved long-term information 

about riverine turbidity, silt and clay concentrations, solar inputs, discharge, and gross primary 

productivity (gpp; via continuous oxygen and temperature measurements – data that are 

collected as parts of the Lake Powell project, Project A.2, and this project) with improved 

additional information about phosphorus (P), gas transfer, and the relative role of diatoms in 

affecting whole river production (Elements E.1 and E.2). These bottom-up drivers are then 

linked to fish populations using field-based measurements of fish growth (via mark recapture) 

and laboratory experiments. 

Science Questions Addressed & Results

• Hypothesis 1 (H1): Glen Canyon Dam outflow is the biggest control on phosphorus (P)

concentrations in Glen Canyon and Marble Canyon, but this influence is dampened the

farther you move downstream from Glen Canyon Dam; storm-based tributary inflows 

also dampen the effect of Glen Canyon Dam outflow on P concentrations of the 

Colorado River.

• H2: The relationship between Colorado River suspended silt-and-clay concentration and 

total P extends to the soluble reactive P (SRP) pool. 

• H3: There is a relatively constant relationship between suspended silt-and-clay

concentration and total P concentration in the tributaries to the Colorado River through 

Grand Canyon. 

Project Lead Charles B. Yackulic

Principal 

Investigator(s) (PI)

Bridget Deemer, USGS, GCMRC

Charles B. Yackulic, USGS, GCMRC

Kimberly Dibble, NPS (formerly with 

USGS, GCMRC)

Michael Yard, USGS, GCMRC 

(Retired)

Theodore Kennedy, USGS, GCMRC

David Ward, USGS, GCMRC

Email cyackulic@usgs.gov

Telephone 928-556-7379
51

• H4: A large fraction of the sediment P pool is calcite bound. 

• H5: We expect equilibrium P concentrations in the Colorado River to be lower in the 

mainstem and higher in the finer, backwater sediments. 

• H6: Lower pH leads to elevated water column P bioavailability due to P release from

calcium carbonates in the sediment. 

• H7: Silt and clay concentrations negatively affect instantaneous gpp via reductions in

light availability.

• H8: High concentrations of silt and clay in the water column have a lagged positive 

effect on gpp via utilization of P bound to deposited silts and clays once the water is

clear again.

• H9: The proportion of gpp in the river due to diatom versus macrophyte production 

varies both seasonally and due to outflow P concentrations in Glen Canyon. 

• H10: Macrophyte species composition and cover in Glen Canyon shifts in response to

flow, temperature, and nutrients. 

• H11: Humpback chub and flannelmouth sucker have lower basal metabolic demands 

than related taxa.

• H12: This low metabolic demand means the ecosystem can sustain large populations of

these species despite relatively low primary production and that these species can

survive through relatively extended periods of low food availability.

Below we focus discussion on FY 2022 efforts to address the science questions posed for each 

of the three elements that comprise Project E (with some recap of work done in FY 2021). This 

includes ongoing P budgeting work, targeted P sediment incubations, vegetation mapping in 

Glen Canyon, and ongoing modeling work that links P, gpp, and secondary production to fish 

growth and population dynamics. 

Project Elements 

Element E.1.

Phosphorus Budgeting 

In total, 423 total phosphorus (TP) samples have been collected across FY 2021 and FY 2022 

toward the construction of a Colorado River P budget (Table 1). Initial results from samples 

collected in FY 2021 show that nearly 90% of the variation in TP concentrations can be 

explained by suspended silt and clay concentrations (n=255, Figure 1). Remarkably, the same lnln relationship holds regardless of the tributary or mainstem location. Storm-triggered samples 

from both the Paria River “PRI” and the Little Colorado River “LCI” represent the upper end of 

both silt and clay and TP concentrations, whereas samples collected from tributaries “TRI” and 

from the mainstem Colorado River “MAIN” span nearly four orders of magnitude for TP (from 

0.002 to 8 mg/L) and five orders of magnitude for silt and clay (from 0.2 to 20,100 mg/L silt & 

clay). Paired samples of dissolved P and silt and clay were limited during FY 2021, with 23 

samples from the Paria River at base flow, 21 samples from storm-based Paria River, and 8 

samples from storm-based Little Colorado River ISCO brand sampler collections. 
52

These samples indicate no predictable relationship between silt and clay concentration and 

dissolved P across locations, but do suggest some relationships within storms. We plan to 

examine these relationships further with the additional dissolved P and silt and clay samples 

collected in 2022 (which are currently waiting to be analyzed at Flathead Lake Biological Station 

and in collaboration with Project A, respectively). 

Table 1. A summary of P samples collected in FYs 2021 and 2022 from the Colorado River below Glen 

Canyon Dam and its tributaries. P samples collected from the Glen Canyon Dam draft tubes and Lees 

Ferry, as part of the Lake Powell Water-Quality Monitoring Program (Appendix A), will also be used for this 

effort. *Indicates that separate suspended-sediment samples were collected for silt and clay concentration 

as part of Project A.

 

Incubations to Examine Controls on Riverine Sediment P Release (Element E1)

In FY 2022, we focused effort on writing up riverine sediment P incubations that were 

conducted in FY 2021. We convened a four-day work group in Moab during early December to 

devise a conceptual diagram, conduct data analyses, and to outline a manuscript. The 

manuscript was submitted to a journal for consideration in early December (Deemer and 

others, submitted). 

Type Sites/ Storms TP Dissolved P Silt & Clay

Paria Base flow 1 (site) 27 27 0

Paria Storm (ISCO) 14 (storms) 109 79 *

Little Colorado River Storm (ISCO) 12 (storms) 76 13 *

Little Colorado River (Grab) 3 (sites) 26 26 26

Diamond Creek 1 (storm) 3 3 3

CS Mainstem 8 (sites) 129 0 13

CS Tributary 21 (tributaries) 53 0 51
53

Figure 1. Positive natural log relationship between mainstem and tributary silt and clay concentration and TP concentration for 

samples collected in FY 2021 (n=155). Color indicates sample location and type (“DC”=Colorado River above Diamond Creek, 

“LCI”=Little Colorado River at Cameron ISCO, “LCR”=Little Colorado River grab sample, “MAIN”=mainstem Colorado River grab 

sample, “PAR”= Paria River grab sample, “PRB”=monthly USGS Paria River base flow grab sample, “PRI”=Paria River ISCO

sample, and “TRI”= tributary grab sample (generally by community scientists). 

These riverine sediment P incubations were conducted to examine the controls on riverine 

sediment P release. The incubation experiment was designed to quantify calcite content in 

sediments and to isolate the effects of redox state (low dissolved oxygen) and pH on sediment 

P release across three sites: Glen Canyon, Pearce Ferry, and the Paria River. Low dissolved 

oxygen concentrations can cause iron bound P release by increasing the solubility of the iron 

(Caraco and others, 1993), whereas low pH can lead to calcite bound P release by increasing the 

solubility of Ca2+ and HCO3

- (Corman and others, 2016). Low pH conditions often co-occur with 

low dissolved oxygen conditions in natural environments due to heterotrophic respiration 

making these mechanisms for P release difficult to disentangle. The incubations successfully 

simulated a range of observed pH (6-8.8) and oxygen (0-9.4 mg L-1) levels. Values of pH were 

chosen to represent the minimum and maximum pH observed at Lees Ferry since dam closure, 

and oxygen concentrations represent a slightly larger range of conditions than are observed in 

the Colorado River (minimum dissolved oxygen of 2.5 mg L-1 observed in Glen Canyon in 

September of 2022 (see Appendix 1). 

We find support for pH-mediated P release from calcite across all three sites. The magnitude of 

P release and total protein production was lower in bottles filled with tailwater sediment than 

in bottles with sediment from downriver sites. At the downriver sites, lower pH treatments 

resulted in declining water column dissolved inorganic phosphorus: soluble reactive

phosphorus (DIN:SRP) ratios, which dropped below the Redfield ratio of 16:1, increasing water 

column total protein production, and down-regulating alkaline phosphatase production. 
54

We estimate that a decline in river pH from 8 to 7 would stimulate downstream sediment P 

release on the same magnitude as SRP loading from the dam outflow. We expect such a decline 

in pH could result from either storm inputs or from shifting the height of dam releases; 

however, downstream pH data are rather limited and the maximum recorded diel range in pH is 

0.25 units (from 7.93 to 8.18 at the U.S. Geological Survey gage site 09383100 Colorado River 

above Little Colorado River near Desert View, AZ; U.S. Geological Survey, 2022; Reibold and 

others, in prep). This additional P supply could be enough to stimulate 1.8 kg d-1 per river 

kilometer of additional aquatic insect production if downstream P limitation is similar to that in 

Glen Canyon (Yard and others, 2023). 

We are currently planning to conduct incubations to quantify equilibrium P concentrations in 

Colorado River sediments in FY 2023. 

Element E.2.

GPP Modeling Progress 

In FY 2022, we published a paper that describes the interacting effects of sub-daily flow 

fluctuations and turbidity on rates of gpp. This included developing a proxy for bed grain size, γ, 

that helps predicts weekly-scale gpp, especially when combined with information about 

discharge and flow regime (hydropeaking or steady; Deemer and others, 2022). A proxy for bed 

grain size is needed because reach-scale bed grain size is not measured as a regular component 

of the Project B monitoring programs (and would be extremely expensive to achieve). Briefly, γ 

is calculated based on the relationship between discharge and turbidity at a given site. Lower 

values of γ indicate a coarser bed grain size distribution (with less turbidity resulting from a set 

discharge), whereas higher values of γ indicate a finer bed grain size distribution (with more 

turbidity resulting from a set discharge). Our model showed higher gpp when γ was low 

(Deemer and others, 2022), consistent with the hypothesis that silt and clay concentrations 

negatively affect instantaneous gpp via reductions in light availability. 

Contribution of Diatoms versus Macrophytes to GPP 

At Lees Ferry, gpp is not correlated with P concentrations, but chlorophyll a is modestly 

correlated with P concentrations. This may be because macrophytes contribute a large fraction 

of gpp, but have access to sediment P stores that the more palatable diatom community does 

not. We hypothesize that, as P increases in the water column, diatom communities increase 

and colonize macrophyte stems and leaves. This colonization shades the plant from sunlight, 

such that primary production from rooted plants will decrease. As such, the proportion of gpp 

in the river due to diatom versus macrophyte production likely varies both seasonally and due 

to outflow P concentrations in Glen Canyon. In FY 2021, a pilot study was conducted primarily 

to refine the methodology used to address this hypothesis (see FY 2021 Annual Report, USGS

Grand Canyon Monitoring and Research Center, 2021). This project has since been discontinued 

because of lack of capacity (and additional priorities being identified). 
55

Aquatic Vegetation Mapping

The purpose of the aquatic vegetation mapping project is to improve our understanding of the 

current macrophyte community in Glen Canyon and to provide a baseline upon which to 

evaluate aquatic vegetation change in response to future flow, temperature, and nutrient 

conditions. In addition to existing underwater imagery taken in 2016 (n=2,738 photos) and 

2019 (n=26,001 photos), an additional 19,345 underwater images were collected prior to, 

during, and after the spring disturbance flow in 2021. These images document the composition 

and cover of aquatic macrophytes, macroalgae, and bryophytes in Glen Canyon at two 

established transects in the upper (~-13 RM) and lower (~-4 RM) sections of the Colorado River, 

which overlap with sites currently sampled for rainbow trout (Oncorhynchus mykiss) and brown 

trout (Salmo trutta) as part of the Trout Recruitment and Growth Dynamics (TRGD) Project (1A, 

1C; Project Element H.2). In 2022, additional images were taken in TRGD sites 1A and 1C to 

expand the use of this application to all 250-m segments in the TRGD reaches, for the purpose 

of relating site-specific macrophyte cover and Potamogeton density to brown trout site specific 

catch data. Image labeling (image-based classification training data collection) was conducted in 

2022 using MakeSense.ai software, and additional labels will be generated in 2023. Models are 

currently in development, and we plan to share results in 2023. 

Storm Phosphorus Incubations

We collected Paria River storm samples and incubated storm water with Colorado River water 

to quantify how storm-based tributary inputs of silt and clay may support lagged positive 

effects on gpp via newly available P. Briefly, we compared the discharge at the USGS gages 

Paria River at Lees Ferry, AZ, 09382000, and the Colorado River at Lees Ferry, AZ, 09380000

(U.S. Geological Survey, 2022), to setup incubations using the flood samples and Colorado River 

water from Lees Ferry (ratios of 1:10.3 and 1:20.2, respectively; Figure 2A). A total of fifteen 

bottles were set up for each time point and bottles were destructively sampled in triplicate 

immediately after bottle set up, and 1, 3, 5 and 7 days later. Bottles were incubated uncapped 

in the dark between 10- and 13-degrees C. Before amending Colorado River water with Paria 

River storm samples, river water concentrations of TDP and SRP were undetectable (< 1.5 and <

0.8 μg L-1 P, respectively) and TP measured 3.1 ug L-1 (Figure 2B). Storm sample amendments 

increased water column P by nearly two orders of magnitude (206 μg L-1 TP, 63.9 μg L-1 TDP, 

and 2.9 μg L-1 SRP). Factor of four increases in water column TDP were maintained throughout 

the 7-day storm simulation experiment (from < 1.5 μg L-1 TDP pre-storm to 6.7 μg L-1 TDP post 

storm), showing that tributary storm inputs can elevate riverine P availability. 
56

Figure 2. Annual discharge for water year 2021 at the USGS gage Paria River at Lees Ferry, AZ, 09382000 (U.S. Geological 

Survey, 2022) (A) and water column P concentrations from bottles incubated for 1 week (B). In panel A, the red dot shows the 

time when samples were collected for the 24-hour incubations (described above); the two blue dots show sample collection times 

for the week-long incubation (described here). Panel B shows water column concentrations of total phosphorus (TP, dark blue), 

total dissolved phosphorus (TDP, purple), and soluble reactive phosphorus (SRP, light blue) prior to amendment with Paria River 

storm water (left of orange vertical line) and post amendment during the week-long incubation. SRP detection limit is plotted as a 

blue horizontal line and samples that came back below the detection limit are plotted at 1⁄2 the detection limit. Note the log scale 

on the y axis in panel B. Taken from Deemer and others, submitted. Preliminary data, do not cite.

Element E.3. 

Laboratory Determinations of Fish Metabolic Rates

One objective of Project Element E.3 is to measure standard and active metabolic rates of largebodied native fish in the Grand Canyon (e.g., humpback chub; Gila cypha and flannelmouth 

sucker; Catostomous latippinis) under laboratory conditions. These fish dominate the biomass 

of Grand Canyon fish communities, but past studies have relied on metabolic rates of related 

species that may not be reliable surrogates. Personnel changes have caused this project to be 

delayed, but we are working on plans to complete this work in FY 2023. 

Ecosystem Models

Another objective of Project Element E.3 is to integrate data in ecosystem models to better 

understand how nutrients, flow, and discharge directly and indirectly affect other trophic levels. 

This year, progress was made in modeling flannelmouth sucker, humpback chub, and rainbow 

trout growth as a function of bottom-up environmental drivers. 
57

Figure 3. Smoothed predicted mean monthly growth in length (mmᐧmonth-1; black line) for a 200 mm flannelmouth sucker for 

four reaches across month intervals together with mean values of environmental covariates: temperature (orange line), GPP 

(green line), turbidity (purple line), and flow (blue line). Plots correspond with: Reach 1) Paria River to Little Colorado River, 

Reach 2) Little Colorado River to Bright Angel Creek, Reach 3) Bright Angel Creek to National Creek, and Reach 4) National 

Creek to Diamond Creek. From Hansen and others, submitted. Preliminary data, do not cite. 

A manuscript was submitted in which flannelmouth sucker growth is modeled as a function of

gpp and water temperature (Hansen and others, submitted). The paper finds that variation in 

gpp is a significant driver of flannelmouth sucker growth (Figure 3). For example, the growth 

model suggests that the 38% increase in canyon-wide gpp during May and June bug flows 

(Deemer and others, 2022) would correspond to an increase in flannelmouth sucker growth of 

1.6 mm per month, or approximately the same effect as warming the river by 1.1 degrees 

Celsius (Hansen and others, submitted). This work represents a first step in developing 

ecosystem models to address questions about metabolic demand. We are working to develop 

models of humpback chub growth that are similar to the models built for flannelmouth sucker. 

These models will quantify relationships between humpback chub growth and gpp and 

temperature in both the Juvenile Chub Monitoring-east (JCM-east) and JCM-west reference 

reaches. 

A second manuscript describes an approach to estimate prey production rates in Lees Ferry 

rates by integrating rainbow trout growth and abundances, literature values for rainbow trout 

bioenergetics, and drift estimates taken through project F (Yard and others, 2023). This 

modeling approach could be extended to downstream fish to form the backbone of future 

ecosystem modeling. The paper links declines in prey production to changing reservoir 

conditions. Another manuscript (described in Project F) models one decade of rainbow trout 

growth in Glen Canyon. The paper quantifies the effects of water-quality (both P and water 

temperature) and compares these to effects of competition, experimental flows, and solar 

insolation (Korman and others, 2022). 
58

Both papers note that declining SRP concentrations in Glen Canyon Dam outflows have 

negative effects on food web production. They also suggest that higher outflow SRP 

concentrations are more likely when Lake Powell is full (Yard and others, 2023; Korman and 

others, 2022). Overall, we continue to make progress in better understanding drivers of 

ecosystem productivity and linkages between ecosystem productivity and numerous LTEMP 

resources including native fish and the rainbow trout fishery.

References

Caraco, N.F., Cole, J.J., and Likens, G.E., 1993, Sulfate control of phosphorus availability in 

lakes—A test and re-evaluation of Hasler and Einsele’s model: Hydrobiologica, v. 253, p. 

275-280, https://doi.org/10.1007/BF00050748. 

Corman, J.R., Moody, E.K., and Elser, J.J., 2016, Calcium carbonate deposition drives nutrient 

cycling in a calcareous headwater stream: Ecological Monographs, v. 86, no. 4, p. 448-461, 

https://doi.org/10.1002/ecm.1229. 

Cross, W.F., Baxter, C.V., Donner, K.C., Rosi-Marshall, E.J., Kennedy, T.A., Hall, R.O., Jr., Wellard 

Kelly, H.A., and Rogers, R.S., 2011, Ecosystem ecology meets adaptive management—Food 

web response to a controlled flood on the Colorado River, Glen Canyon: Ecological 

Applications, v. 21, no. 6, p. 2016-2033, https://doi.org/10.1890/10-1719.1. 

Deemer, B.R., Reibold, R., Fatta, A., Corman, J.R., Yackulic, C.B., and Reed, S.C., submitted, pH of 

dam releases affects downstream phosphorus cycling in an arid regulated river: Ecological 

Applications. 

Deemer, B.R., Yackulic, C.B., Hall, R.O., Jr., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J.D., 

Topping, D.J., Voichick, N., and Yard, M.D., 2022, Experimental reductions in sub-daily flow 

fluctuations increased gross primary productivity for 425 river kilometers downstream: 

PNAS Nexus, v. 1, no. 3, pgac094, https://doi.org/10.1093/pnasnexus/pgac094.

Hansen, L.E., Yackulic, C.B., Dickson, B.G., Deemer, B.R., and Best, R.J., submitted, Linking 

ecosystem processes to consumer growth rates—Gross primary productivity as a driver of 

freshwater fish somatic growth in a resource-limited river: Canadian Journal of Fisheries and 

Aquatic Sciences. 

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Reibold, R., Fatta, A., Voichick, N., Goodenough, D., and Deemer, B.R., in prep, Phosphorus, 

nitrogen, carbon, pH, and dissolved oxygen data from incubations of Colorado River water 

and sediment: U.S. Geological Survey data release. 

U.S. Geological Survey Grand Canyon Monitoring and Research Center, 2021, Fiscal Year 2021 

Annual Project Report to the Glen Canyon Dam Adaptive Management Program: Flagstaff, 

Ariz., prepared by the U.S. Geological Survey, Southwest Biological Science Center, Grand 

Canyon Monitoring and Research Center, December 16, 2021, 251 p.

U.S. Geological Survey, 2022, National Water Information System: U.S. Geological Survey web 

interface, https://waterdata.usgs.gov/nwis. Cited September 2022 at 

https://waterdata.usgs.gov/nwis. 
59

Wellard Kelly, H.A., Rosi-Marshall, E.J., Kennedy, T.A., Hall, R.O., Jr., Cross, W.F., and Baxter, 

C.V., 2013, Macroinvertebrate diets reflect tributary inputs and turbidity-driven changes in 

food availability in the Colorado River downstream of Glen Canyon Dam: Freshwater 

Science, v. 32, no. 2, p. 397-410, https://doi.org/10.1899/12-088.1. 

Yard, M.D., Yackulic, C.B., Korman, J., Dodrill, M.J., and Deemer, B.R., 2023, Declines in prey 

production during the collapse of a tailwater rainbow trout population are associated with 

changing reservoir conditions: Transactions of the American Fisheries Society, v. 152, no. 1, 

p. 35-50, https://doi.org/10.1002/tafs.10381. 

Project E Budget

Burden

12.326%

Budgeted

Amount $200,851 $10,500 $17,272 $14,500 $0 $28,615 $271,738 

Actual

Spent $178,114 $3,893 $21,314 $5,000 $0 $25,211 $233,532 

(Over)/Under

Budget $22,737 $6,607 ($4,042) $9,500 $0 $3,404 $38,206 

FY21 Unspent Funds $0 FY22 Unspent Funds $38,206

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Underspent Salaries is due to HR-delays in hiring and staff turnover.

- Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Overspent in Operating Expenses is for purchases of necessary lab equipment.

- Underspent funds in Cooperative Agreements is due to funds obligated in FY22 that will be expended in FY23. 

Project E Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
60

Project E Deliverables: Controls on Ecosystem Productivity: Nutrients, Flow and 

Temperature

Presentations:

Bruckerhoff, L., Wheeler, K., Dibble, K., Mihalevich, B., Neilson, B., Wang, J., Yackulic, C., and 

Schmidt, J., 2022, Water storage decisions and consumptive use constrain ecosystem 

management under severe sustained drought—virtual presentation: Desert Fishes Council 

2022 Annual Meeting, St. George, Utah.

Deemer, B.R., 2022, Beyond eco-flow—Understanding biogeochemical links between limnology 

and management in human-made reservoirs—presentation: Joint Aquatic Science Meeting

(JASM 2002), Grand Rapids, MI.

Deemer, B.R., Reibold, R., Fatta, A., Corman, J., Yackulic, C.B., and Reed, S., 2022, Links between 

drought and river nutrition—Phosphorus export from Glen Canyon Dam under declining 

reservoir elevations—presentation: 16th Biennial Conference of Science and Management 

on the Colorado Plateau and Southwest Region, Flagstaff, AZ.

Deemer, B., Yackulic, C., Hall, R., Dodrill, M., Kennedy, T., Muehlbauer, J., Topping, D., Voichick, 

N., and Yard, M., 2022, Turning the red river green: An experimental flow increases primary

production in the Colorado River—presentation for Friday’s Findings webinar, U.S. 

Geological Survey Ecosystems Mission Area, Reston, Va., January 14, 2022, U.S. Geological 

Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research 

Center.

Dibble, K.L., 2022, Aquatic plants, food webs, and fish populations in the Colorado River in Glen 

Canyon Dam National Recreation Area—Outreach river trip and science presentation to the 

2022 Native Youth Science Camp, Flagstaff, AZ.

Dibble, K.L., Bruckerhoff, L.A., Yackulic, C.B., Schmidt, J.C., Bestegen, K.R., Kennedy, T.A., 

Mihalevich, B.A., Neilson, B.T., Wang, J., and Wheeler, K., 2022, Forecasting the influence of 

climate change, water storage decisions, and consumptive use on fishes of the Colorado 

River basin—Oral presentation and virtual panel for the Department of Interior’s Turbine 

Talk Webinar Series focused on ‘USGS Science on Climate Impacts on Hydropower’.

Dibble, K.L., Yard, M., Tusso, R., and Buscombe, D., 2022, Aquatic vegetation in Glen Canyon—

Observations following a spring disturbance flow—presentation: Glen Canyon Dam 

Adaptive Management Program Annual Reporting Meeting, January 11-12, 2022, Southwest 

Biological Science Center, Grand Canyon Monitoring and Research Center. 

Hansen, L.E., and Yackulic, C.B., 2022, Linking ecosystem processes to consumer growth rates—

Gross primary productivity and temperature drive fish growth—presentation: Joint Aquatic 

Science Meeting (JASM 2002), Grand Rapids, MI.

Journal Articles:

Deemer, B.R., Reibold, R., Fatta, A., Corman, J.R., Yackulic, C.B., and Reed, S.C., submitted, pH of 

dam releases affects downstream phosphorus cycling in an arid regulated river: Ecological 

Applications. 
61

Deemer, B.R., Yackulic, C.B., Hall, R.O., Jr., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J.D., 

Topping, D.J., Voichick, N., and Yard, M.D., 2022, Experimental reductions in sub-daily flow 

fluctuations increased gross primary productivity for 425 river kilometers downstream: 

PNAS Nexus, v. 1, no. 3, pgac094, https://doi.org/10.1093/pnasnexus/pgac094.

Hansen, L.E., Yackulic, C.B., Dickson, B.G., Deemer, B.R., and Best, R.J., submitted, Linking 

ecosystem processes to consumer growth rates—Gross primary productivity as a driver of 

freshwater fish somatic growth in a resource-limited river: Canadian Journal of Fisheries and 

Aquatic Sciences. 

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related 

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Yard, M.D., Yackulic, C.B., Korman, J., Dodrill, M.J., and Deemer, B.R., 2023, Declines in prey 

production during the collapse of a tailwater rainbow trout population are associated with 

changing reservoir conditions: Transactions of the American Fisheries Society, v. 152, no. 1, 

p. 35-50, https://doi.org/10.1002/tafs.10381. 

USGS Data Releases:

Deemer, B.R., Yard, M.D., Voichick, N., Goodenough, D.C., Bennett, G.E., Hall Jr., R.O., Dodrill, 

M.J., Topping, D.J., Gushue, T., Muehlbauer, J.D, Kennedy, T.A., and Yackulic, C.B., 2022, 

Gross primary production estimates and associated light, sediment, and water quality data 

from the Colorado River below Glen Canyon Dam: U.S. Geological Survey data release, 

https://doi.org/10.5066/P9ZS6YLV. 

Hansen, L.E., and Yackulic, C.B., 2022, Mark-recapture and environmental data used to predict 

flannelmouth sucker (Catostomous latippinis) growth rates within the Colorado River in the 

Grand Canyon from April 2012 to October 2018: U.S. Geological Survey data release, 

https://doi.org/10.5066/P9852I1G. 

Yackulic, C. B., M. D. Yard, J. Korman, M. J. Dodrill, and B. R. Deemer. 2022. Proximal and distal 

factors associated with the decline in secondary invertebrate prey production in the 

Colorado River, Glen Canyon, Arizona: U.S. Geological Survey data release, 

https://doi.org/10.5066/P9UZTYPV. 
62

Project F: Aquatic Invertebrate Ecology

Goals and Objectives

The principal goal of our work this year was monitoring invertebrate population response to the 

Macroinvertebrate Production Flows (Bug Flows) experiment that occurred on weekends from 

May-August 2022. To monitor the food base and invertebrate populations in Grand Canyon, we 

continued partnering with river guides and education groups through our community science 

light trapping project. This project has been ongoing since 2012 and provides a powerful tool 

for tracking invertebrate population response to adaptive management experimentation and 

changing environmental conditions. We continued monthly food base monitoring in the Glen 

Canyon reach to inform trends in trout populations, and we continued food base data 

collections in reaches where humpback chub (Gila cypha) populations appear to be growing 

(see Project G). In 2022, we also began new diet studies on native fish using non-lethal methods 

that include environmental DNA (eDNA) analysis of fish feces and stable isotope analysis of fish 

fin clips. We used entirely non-lethal methods for quantifying fish feeding habits to honor Tribal 

concerns about the taking of life. 

Research and monitoring of invertebrate assemblages described in Project F informs the LTEMP 

Goal for Natural Processes. Project F also provides essential context and data that are used by 

other projects in evaluation of other LTEMP goals. For example, invertebrate monitoring data 

are used by Project E (Controls on ecosystem productivity) to identify the extent to which 

changing nutrient levels are propagating up through the food web. Invertebrate monitoring 

data collected in Project F also aid interpretation of seasonal and annual trends in humpback 

chub (Project G) and rainbow trout (Project H), because aquatic invertebrates represent the 

food base for these fish. Project F also integrates and uses data from other projects, particularly 

Project A (streamflow, water quality, and sediment transport) and Project B (habitat mapping),

to identify how changing environmental and habitat conditions affect invertebrate populations. 

Details of this ongoing project are provided in the GCMRC FY 2021–23 Triennial Work Plan (U.S. 

Department of the Interior, 2020).

Project Lead Theodore Kennedy

Principal 

Investigator(s) (PI)

Theodore Kennedy, USGS, GCMRC

Anya Metcalfe, USGS, GCMRC

Jeff Muehlbauer, USGS, Alaska Coop Unit

Morgan Ford, USGS, GCMRC

Charles Yackulic, USGS, GCMRC

Mike Dodrill, USGS, WFRC

Email tkennedy@usgs.gov

Telephone (928) 556-7374
63

Science Questions Addressed & Results

Project Elements 

Element F.1. Invertebrate Monitoring in Grand Canyon 

Community science light trapping has been the backbone of our invertebrate monitoring in 

Grand Canyon since 2012 (Kennedy and others, 2016; see Figure 1). In 2022, community science 

sampling yielded 606 light trap samples of adult aquatic insects spanning more than 285 miles 

of the Colorado River, from April-October. Analysis of the 2022 light trap samples was 

presented at the Annual Reporting Meeting in January 2023. These data are being compared to 

light trap catches from prior years to evaluate effects of experimental Bug Flows, changing 

environmental conditions, and other factors on aquatic insect abundance throughout Grand 

Canyon. 

We launched one Grand Canyon river trip in April 2022 to quantify invertebrate drift 

concentrations approximately every ten miles throughout Glen, Marble, and Grand Canyons. 

These data will be compared to similar drift data that were collected annually in 2017-2021 to 

evaluate effects of the Bug Flows experiment on invertebrate assemblages and drift biomass. 

Processing of drift river trip samples from 2017-2021 has been completed and was presented at 

the Annual Reporting Meeting. As part of this annual river trip, drift is collected at juvenile 

humpback chub monitoring locations (Little Colorado River confluence and Fall Canyon). 

Dissolved oxygen sensors (Mini-DOTs) for monitoring gross primary production (in support of 

Project E) are also cleaned and maintained on this trip. Collaborators from Oregon State 

University also participated to collect eDNA samples from tributary and mainstem locations and 

evaluate suitability of this new method for quantifying diversity and species richness of 

invertebrate assemblages (see F.3, Invertebrate monitoring in Tributaries, below). 

In 2022, community scientists collected acoustic bat activity data paired with 262 of the light 

trap samples. Paired bat acoustic and insect monitoring data from 2017-2020 have been 

analyzed and revealed that bat activity (# of calls per hour) was positively related to the 

abundance of aquatic flies (Diptera) in Grand Canyon. Furthermore, aquatic flies as a predictor 

outcompeted all other invertebrate prey categories (e.g., moths, terrestrial insects) and 

environmental variables (e.g., vegetation cover, lunar phase, air temperature) in our models. 

We submitted a manuscript describing these findings in September of 2022 (Metcalfe and 

others, in review), and it has been tentatively accepted pending revision. 

To improve opportunities for diverse audiences to learn about the scientific process and 

participate in monitoring, GCMRC has partnered with Grand Canyon Youth to launch Partners in 

Science river trips for more than 20 years. Each of these Partners in Science trips engage 

approximately 20 high school age students in data collection and monitoring activities including 

light trapping and bat acoustic monitoring reported here. One of the three Partners trips 

launched in 2022 was comprised entirely of Tribal youth participants. 
64

Element F.2. Invertebrate Monitoring in Glen Canyon 

In FY 2022 our group continued long-term monitoring of the aquatic food base in the Lees Ferry 

sport fishery. This monitoring includes monthly drift, sticky trap, and light trap sampling from 

Glen Canyon Dam (RM -15) to the Lees Ferry boat ramp (RM 0). In support of monitoring the 

Bug Flows experiment, we conducted two additional intensive sampling bouts that entailed 

collecting drift, sticky trap, and light trap samples daily during routine weekday hydropower 

fluctuations and steady low Bug Flows releases (i.e., daily sampling on a Friday through 

Monday). These intensive sampling bouts occurred from May 13-16 and June 10-13, 2022. 

Collectively, these data will allow us to track invertebrate populations in the Lees Ferry sport 

fishery using a variety of sampling methods and on robust spatial and temporal scales. Although 

monthly sample collections occurred as planned in 2022, laboratory sample processing is 

ongoing and results were not available at January’s Annual Reporting Meeting. 

Figure 1. Average caddisfly (blue line) and midge abundance (red line) collected in community science light traps from 2012 

through 2021. Annual average values appear above each point and are estimated from a mixed-effects model that accounts for 

variation in sampling effort across reaches and across years. Error bars represent one standard error. The abundance of 

caddisflies increased by ~400% during two of three years of Bug Flows experimentation (2018-2020) compared to the pre-Bug 

Flows baseline from 2012-2017. The abundance of midges was also predicted to increase with Bug Flows, but no such increase 

was detected during 2018-2020. However, in 2021 when Bug Flows were paused, midge abundance declined by 50 percent (a 

statistically significant decline) while caddisfly abundance remained unchanged (not statistically different) from the year prior. 
65

Element F.3. Invertebrate Monitoring in Tributaries 

In response to a request from the National Park Service, our group continued studies of the 

food base in Bright Angel Creek associated with ongoing trout removal efforts and the 

reintroduction of humpback chub in 2018 and 2020. We sampled aquatic invertebrates in 

Bright Angel Creek once in FY 2022. In coordination with the USGS-Youth and Education in 

Science (YES) office, we hired a summer intern to help move forward on processing backlogged 

samples collected in prior years. We have been conducting these sampling trips since 2016 and 

now have a data set that spans multiple years of trout removal in addition to humpback chub 

reintroduction. This work will allow us to explore how the food web in Bright Angel Creek has 

responded to these management actions and what invertebrate food may be available for the 

translocated humpback chub. Analysis of these data is ongoing, and a manuscript describing 

these studies is under development.

Unregulated tributaries within the Grand Canyon have the potential to act as sources of 

invertebrate biodiversity for the mainstem, although the degree to which this occurs is 

unknown. To address this question of invertebrate diversity in mainstem versus tributary 

locations, we have been collaborating with Oregon State University scientists and graduate 

students to use an eDNA metabarcoding approach to assemble a data set of invertebrate 

community diversity in tributaries and the mainstem. Collaborators at Oregon State collected 

eDNA samples from 36 locations in the Grand Canyon corresponding to 18 paired mainstem 

and tributary locations in 2021. In 2022, 42 locations (21 pairs of sites) were sampled. Samples 

from the 2021 campaign have been processed while 2022 samples are still being processed. 

Diptera were the most common insect order in both mainstem and tributary locations, 

representing 62% of the identified OTUs. Non-metric multi-dimensional scaling ordination of 

sample sites shows a distinct grouping of mainstem and tributary sites, with statistically 

significant differences in both aquatic invertebrate community composition and variability 

within each group. Additionally, both tributary and mainstem groups show a shift in community 

composition associated with downstream distance from Glen Canyon Dam. These findings 

highlight the importance of Grand Canyon tributaries for preserving aquatic invertebrate 

biodiversity and reveal a wide diversity of Diptera that has previously been underrepresented in 

morphological taxonomy. Furthermore, this work demonstrates the utility of eDNA as a tool for 

monitoring invertebrate communities in the Grand Canyon. 

Element F.4. Fish Diet Studies 

Element F.4 includes analysis of existing rainbow and brown trout diet data from Lees Ferry. It 

also includes collection of new diet samples for native fish in Grand Canyon. In FY 2022, we 

collected samples of fish fin clips for stable isotope analysis on a seasonal basis. Stable isotope 

analysis of fin clips provides insights into feeding habits of fish. Sample totals were 349 fin clips 

from flannelmouth sucker and 104 fin clip samples from humpback chub. In FY 2022, we also 

collected fecal samples from native fish on a seasonal basis. 
66

These fecal samples will be analyzed using the same eDNA laboratory process at Oregon State 

University that has been successful at identifying invertebrate communities from water samples 

(see Element F.3, above). This will provide detailed information on invertebrate species that are 

being consumed by native fish. Samples totals for FY 2022 include 239 flannelmouth sucker 

feces and 49 humpback chub feces. 

References

Kennedy, T.A., Muehlbauer, J.D., Yackulic, C.B., Lytle, D.A., Miller, S.W., Dibble, K.L., 

Kortenhoeven, E.W., Metcalfe, A.N., and Baxter, C.V., 2016, Flow management for 

hydropower extirpates aquatic insects, undermining river food webs: BioScience, v. 66, no. 

7, p. 561-575, https://doi.org/10.1093/biosci/biw059. 

Metcalfe, A., Kennedy, T., Fritzinger, C., Dodrill, M.J., Szydlo, C.M., Muehlbauer, J.D., Yackulic, 

C.B., Holton, B.P., Durning, L.E., Sankey, J.B., and Weller, T.J., in review, Insectivorous bat 

foraging tracks the availability of aquatic flies (Diptera): Journal of Wildlife Management. 

U.S. Department of the Interior, 2020, Glen Canyon Dam Adaptive Management Program 

Triennial Budget and Work Plan—Fiscal years 2021-2023—Final approved by the Secretary 

of the Interior—December 2, 2020: Flagstaff, Ariz., U.S. Geological Survey, Grand Canyon 

Monitoring and Research Center, and Salt Lake City, Utah, Bureau of Reclamation, Upper 

Colorado Region, 384 p., 

http://gcdamp.com/images_gcdamp_com/5/5d/GCMRC_TWP2021-

23_December2_2020_ApprovedBySecretary.pdf. 

Project F Budget

Burden

12.326%

Budgeted

Amount $503,666 $15,283 $37,810 $0 $0 $68,626 $625,385 

Actual

Spent $537,820 $13,728 $42,304 $0 $0 $73,198 $667,051 

(Over)/Under

Budget ($34,154) $1,555 ($4,494) $0 $0 ($4,572) ($41,666)

FY21 Unspent Funds $17,816 FY22 Unspent Funds ($23,850)

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Overspent Salaries is due to promotions among staff and overtime associated with Bug Flow field studies and fall seining trip.

- Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Overspent in Operating Expenses is for payments to community science participants and purchase of additional drift sampling 

equipment needed to provide JCM trips with their own gear for collection on trips.

Project F Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
67

Project F Deliverables: Aquatic Invertebrate Ecology

Presentations:

Kennedy, T., 2022, Background and design of the Bug Flows hydrograph—virtual presentation: 

Science Advisor review of the Bug Flow experiment, Day 1, October 2022.

Kennedy, T., 2022, Bug Flows and the rainbow trout fishery—virtual presentation: Science 

Advisor review of the Bug Flow Experiment, Day 1, October 2022.

Kennedy, T., 2022, Discussion of the Bug Flow synthesis and review and opportunities for Spring 

and Summer Flow Experiments—virtual presentation: Glen Canyon Dam Adaptive 

Management Program Technical Work Group Meeting, January 2022, Southwest Biological 

Science Center, Grand Canyon Monitoring and Research Center. 

Kennedy, T., 2022, Potential next steps in flow experimentation—virtual presentation: Science 

Advisor review of the Bug Flow Experiment, Day 2, November 2022. 

Kennedy, T., and Muehlbauer, J., 2022, Project F—Aquatic ecology and food base monitoring—

virtual presentation: Glen Canyon Dam Adaptive Management Program Annual Reporting 

Meeting, January 11-12, 2022, Southwest Biological Science Center, Grand Canyon 

Monitoring and Research Center. 

Kennedy, T. and Muehlbauer, J., 2022, Project F—Aquatic ecology and food base monitoring—

virtual presentation: Glen Canyon Dam Adaptive Management Program Adaptive 

Management Work Group Meeting, February 2022, Southwest Biological Science Center, 

Grand Canyon Monitoring and Research Center. 

Kennedy, T.A., Muehlbauer, J.D., Deemer, B.R., Yackulic, C.B., Ford, M.A., Szydlo, C., Metcalfe, 

A.N., and Lytle, D.A., 2022, Experimental Bug Flows increase algae production and insect 

diversity in the Colorado River, Grand Canyon—presentation: Joint Aquatic Sciences 

Meeting (JASM 2022), Grand Rapids, MI, May 2022.

Kennedy, T.A., Muehlbauer, J.D., Deemer, B.R., Yackulic, C.B., Ford, M.A., Szydlo, C., and 

Metcalfe, A.N., 2022, Experimental ‘Bug Flows’ increased algae production and insect 

diversity in the Colorado River, Grand Canyon: 16th Biennial Conference of Science and 

Management for the Colorado Plateau, Flagstaff, AZ, September 2022. 

Freedman, J.W., Burke, M.K., Kennedy, T.A., and Lytle, D.A., 2022, Environmental DNA 

metabarcoding reveals aquatic invertebrate community diversity in the Grand Canyon—

presentation: Joint Aquatic Sciences Meeting (JASM 2022), Grand Rapids, MI, May 2022.

Metcalfe, A.N., Fritzinger, C.A., Kennedy, T.A., Dodrill, M.J., Muehlbauer, J.D., Holton, B., 

Durning, L.E., Sankey, J.B., and Weller, T., 2022, Bats, bugs, and boaters—Insectivorous bat 

foraging along the Colorado River in Grand Canyon is determined by the availability of 

aquatic flies: 16th Biennial Conference of Science and Management for the Colorado 

Plateau, Flagstaff, AZ, September 2022.

Metcalfe, A., Kennedy, T., Muehlbauer, J., Dodrill, M., Durning, L., Sankey, J., and Fritzinger C., 

2022, The role of insect abundance and riparian vegetation in driving bat foraging activity in 

Grand Canyon—Insights from a community science project—virtual presentation: Glen 

Canyon Dam Adaptive Management Program Annual Reporting Meeting, January 11-12, 

2022, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center. 
68

Metcalfe, A.N., Kennedy, T., Muehlbauer, J.D., Dodrill, M.J., Weller, T., Durning, L., Sankey, J.B., 

and C.A. Fritzinger, 2022, Insectivorous bat foraging along the Colorado River in Grand 

Canyon is determined by aquatic prey availability and tall vegetation density—presentation: 

Joint Aquatic Sciences Meeting (JASM 2022), Grand Rapids, MI, May 2022.

Muehlbauer, J., 2022, Bug Flows—Invertebrate response—virtual presentation: Science Advisor 

review of the Bug Flow Experiment, Day 1, October 2022. 

Traynham, L. and Kennedy, K., 2022, “Potential LTEMP experiments Spring/Summer 2022—

virtual presentation: Glen Canyon Dam Adaptive Management Program Technical Work 

Group Meeting, April 2022, Southwest Biological Science Center, Grand Canyon Monitoring 

and Research Center. 

Journal Articles:

Deemer, B.R., Yackulic, C.B., Hall, R.O., Jr., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J.D.,

Topping, D.J., Voichick, N., and Yard, M.D., 2022, Experimental reductions in sub-daily flow 

fluctuations increased gross primary productivity for 425 river kilometers downstream: 

PNAS Nexus, v. 1, no. 3, pgac094, https://doi.org/10.1093/pnasnexus/pgac094. 

Kennedy, T.A., Metcalfe, A.N., Deemer, B.R., Ford, M.A., Szydlo, C.M., Yackulic, C.B., and 

Muehlbauer, J.D., 2022, Little bugs, big data, and Colorado River adaptive management—

Preliminary findings from the ongoing bug flow experiment at Glen Canyon Dam: Boatman's

Quarterly Review, v. 35, no. 3, p. 26-31. (Not available online)

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Metcalfe, A., Kennedy, T., Fritzinger, C., Dodrill, M.J., Szydlo, C.M., Muehlbauer, J.D., Yackulic, 

C.B., Holton, B.P., Durning, L.E., Sankey, J.B., and Weller, T.J., submitted, Insectivorous bat 

foraging tracks the availability of aquatic flies (Diptera): Journal of Wildlife Management. 
69

Project G: Humpback Chub Population Dynamics throughout 

the Colorado River Ecosystem

Goals and Objectives

• Accurately estimate the abundance of various life stages (e.g., juveniles, subadults, 

adults) of humpback chub to inform triggers associated with the 2016 Biological Opinion 

(U.S. Department of the Interior, 2016b). 

• Use models to learn about relationships between environmental factors and humpback 

chub life history to forecast impacts of management actions on future abundances. 

• Improve estimation approaches to obtain more precise abundance estimates, including 

assessing the potential benefits of new technologies and(or) sampling methods. 

• Quantify the efficacy of existing management actions, and potential alternative

management strategies, for increasing or maintaining humpback chub abundances. 

Project Elements 

Element G.1. Humpback Chub Population Modeling 

Science Questions/Hypotheses Addressed 

In FY 2022, model development focused primarily on answering the following scientific 

questions: 1) how do survival and growth rates in western Grand Canyon compare to those of 

humpback chub (Gila cypha) in the Little Colorado River aggregation? and 2) can we use 

detections from a multiplexer array (see project G.4) to improve abundance estimation in the 

Little Colorado River? In addition to these two model development projects, we also used our 

established models of humpback chub in the Little Colorado River aggregation to learn whether 

or not abundance estimates in the Little Colorado River aggregation were above biological 

triggers, which are linked to management actions such as trout removals (U.S. Department of 

the Interior, 2016a).

Project Lead Charles B. Yackulic

Principal 

Investigator(s) (PI)

Maria Dzul, USGS, GCMRC

Charles B. Yackulic, USGS, GCMRC

Mariah Giardina, USGS, GCMRC

Kirk Young, USFWS

Randy Van Haverbeke, USFWS

David Ward, USGS, GCMRC

Laura Tennant, USGS, GCMRC

Email cyackulic@usgs.gov

Telephone (928) 556-7379
70

Results 

Results from the JCM-west model will be included in a manuscript that is expected to be 

submitted to a scientific journal early in FY 2023. We have developed and fit a novel model that 

integrates the multiplexer data alongside standard sampling and are conducting simulations to 

ensure estimates are unbiased. We will continue development of this model in FY 2023. The 

multistate model for annual reporting in FY 2021 indicated that chub adult abundances 

remained above 9,000 and the U.S. Fish and Wildlife Service (USFWS) estimate of the running 3-

year average of large subadults in the Little Colorado River was greater than 1,250. However, 

due to a low 3-year running average of subadult abundance in the JCM-east reach (mean 

abundance less than 810), we were in Tier 1 for biological triggers (U.S. Department of the 

Interior, 2016a) in FY 2021. Abundances for 2022 associated for biological triggers (currently 

being estimated) will be reported at the annual reporting meeting. 

Element G.2. Annual Spring/Fall Humpback Chub Abundance Estimates in the Lower 13.6 km of the 

Little Colorado River

Science Questions/Hypotheses Addressed 

This is part of a long-term monitoring program with the goal to monitor the population status 

and trends of humpback chub in the Little Colorado River to help answer these questions:

 

• What are the length-stratified abundance estimates of humpback chub (e.g., > 100 mm,

≥ 150 mm, ≥ 200 mm TL) in the lower 13.6 km of the Little Colorado River during the 

spring and fall? 

• What does this imply for population trends?” 

Abundance estimates from these monitoring efforts are used to inform actions and triggers 

associated with the 2016 Biological Opinion (U.S. Department of the Interior, 2016b). 

Results 

In 2022, USFWS and volunteers conducted four monitoring trips (during April, May, September, 

and October) to monitor humpback chub in the Little Colorado River. During spring 2022, we 

estimated that there were 10,500 (Standard Error [SE] = 700) humpback chub ≥ 150 mm total 

length (TL), of which 8,500 (SE = 700) were ≥ 200 mm TL in the Little Colorado River (Figure 1). 

These numbers represent a significant increase from the spring 2021 estimates and were 

similar to 2019 estimates (2020 spring estimates were not obtained because of Covid impacts). 

In fall 2021, it was estimated that there were 3,800 (SE = 300) HBC ≥ 150 mm TL in the Little 

Colorado River. Of these fish, an estimated 1,900 (SE = 200) were ≥ 200 mm TL (Figure 1). 
71

 

Figure 1. Chapman Petersen abundance estimates (±95% CI) of humpback chub ≥ 150 mm total length (TL) and ≥ 200 mm TL 

in the Little Colorado River (0-13.57 river km) during spring 2001-2022 (upper panel) and fall 2000-2021 (lower panel). Note: 

closed spring and fall abundance estimates of humpback chub > 150 mm TL in the Little Colorado River during 1991 and 1992 

are from Douglas and Marsh (1996), and no spring 2020 estimates were obtained because of Covid impacts. Preliminary data, 

do not cite.

Element G.3. Juvenile Humpback Chub Monitoring near the Little Colorado River Confluence

Science Questions/Hypotheses Addressed 

• What are the abundance estimates of humpback chub in the Little Colorado River

aggregation and what does this imply for population trends (increasing, stable,

decreasing)? 

• Which environmental conditions are favorable for humpback chub production in the 

Little Colorado River? 

• Which environmental factors influence humpback chub outmigration from the Little 

Colorado River to the Colorado River?

Abundance estimates are used to inform triggers associated with the 2016 Biological Opinion 

(U.S. Department of the Interior, 2016b). 
72

Results 

In 2022, three sampling trips (in April, July, and October) were conducted in the JCM-east reach, 

and one June trip was conducted at the Little Colorado River. We caution that data reported 

here are provisional and have not been fully checked for quality control. Flannelmouth sucker 

(Catostomus lattipinnis) were the most frequently caught species in JCM-east catch (2491), 

followed by humpback chub (1443), fathead minnow (Pimephales promelas) (1037), rainbow 

trout (Oncorhynchus mykiss) (723), bluehead sucker (Catostomus discolobus) (388), channel 

catfish (Ictalurus punctatus) (210), plains killifish (Fundulus zebrinus) (51), carp (Cyprinus carpio) 

(33), black bullhead (Ameiurus melas) (28), speckled dace (Rhinichthys osculus) (27), brown 

trout (Salmo trutta) (7), yellow bullhead (Ameiurus natalis) (6), bluegill (Lepomis macrochirus)

(1), red shiner (Cyprinella lutrensis) (1), and black crappie (Pomoxis nigromaculatus) (1). In total, 

all JCM-east trips captured 787 humpback chub > 79 mm TL and marked 642 humpback chub 

between (40-79 mm TL) with visual implant elastomer (VIE), a fluorescent pigment injected 

under the fishes’ skin. Catch of humpback chub > 79 mm TL was 64 in May, 434 in July, and 289 

in October. In addition, the number of humpback chub given a VIE (between 40-79mm TL) was 

21 in April, 33 in July, and 588 in October. Age-0 abundance in the Little Colorado River in July 

was moderate in 2022 compared to 2013-2021 (Figure 2). 

The large number (catch = 209) of channel catfish captured during the October 2022 trip 

represents an all-time high compared to previous years of JCM sampling (2012-2021), where 

previously the maximum catch of channel catfish occurred in April 2015 (catch = 12) followed 

closely by January 2015 (catch = 11), with other trips capturing between 0-6 catfish. 

Importantly, channel catfish captured during October 2022 were all 53-104 mm fork length. 

Figure 2. Estimated abundance of age-0 humpback chub (i.e., < 80 mm total length (TL)) during mid-summer sampling trips to 

the lower 13.6 km of Little Colorado River. Preliminary data, do not cite. 

Element G.4. Remote PIT-Tag Array Monitoring in the Little Colorado River

Science Questions/Hypotheses Addressed 

• Can detection from remote passive integrated transponder (PIT)-tag arrays be used to 

improve estimation of abundance and movement for adult humpback chub? 
73

• How does the number of adult humpback chub moving into the Little Colorado River

(and presumably spawning in the Little Colorado River) fluctuate from year to year?

• How does movement timing for adult humpback chub vary from year to year and how 

does this influence estimation of adult abundance in the Little Colorado River? 

Results

The multiplexer (MUX) is comprised of two arrays (in situ chains of PIT tag antennas that stretch 

across the river), located ~1.7 river kilometers (rkm) upstream of the confluence with the 

Colorado River; by convention, distances in the Little Colorado River are measured in kilometers 

upstream from its confluence with the Colorado River. The MUX can read PIT tags of fish that 

swim past it, offering an alternative method for detecting PIT tags that does not rely on physical 

capture. Detections from these antennas are used to supplement Little Colorado River sampling 

efforts to learn more about availability (i.e., probability migrating fish are in the Little Colorado 

River during USFWS sampling) and movement timing. 

This new MUX system installed in November 2020 has shown very high detection probabilities 

over the last two years, detecting 7,700 unique tags (including 4,352 unique humpback chub 

tags) in spring 2021 (March 21-June 15) and 10,126 unique tags (including 5,406 unique 

humpback chub tags) in 2022 (February 15 – June 15). Preliminary results from a Little Colorado 

River -MUX detection model suggest that in 2022, the MUX detection probability (i.e., 

probability of being detected by at least one array) for marked, migrating humpback chub was 

94% for upstream movement and 41% for downstream movement (Figure 3). Currently, the 

MUX is non-operational after flood damage in summer and fall of 2022, but plans to repair this 

system during winter 2022/2023 are currently in development. 

Figure 3. Probability densities of upstream movement (pink) and downstream movement (blue) detections in 2021 (nupstream = 

1725, ndownstream= 326) and 2022 (nupstream = 2635, ndownstream= 172). Upstream and downstream detections were identified if a fish 

was detected on both the upstream and downstream array and these detections occurred within one hour of each other. The red 

and blue vertical lines correspond to the mean upstream and downstream movement dates, respectively. Data from February 15- 

March 21 were lost due to a data backup error (black shaded; unpublished data). 
74

Element G.5. Monitoring Humpback Chub Aggregation Relative Abundance and Distribution 

Science Questions/Hypotheses Addressed 

• What are trends in long-term (catch-per-unit effort (CPUE)) and(or) abundance of 

humpback chub in the historical “aggregation” sites (Valdez and Ryel, 1995) as well as

throughout western Grand Canyon? 

Results 

The results presented here are relevant up to 2021, because mainstem aggregation data for 

2022 are still being analyzed. A substantial increase in the abundance of humpback chub has 

occurred in western Grand Canyon, beginning with spikes of age 0 humpback chub in 2014 that 

translated into substantial increases in the adult population starting in 2017 (Figure 4). This 

increase in adults is thought to be caused by increases in water temperature, which exceeded 

~19 °C in 2014, and were within suitable spawning temperatures for humpback chub. The 

increase appears to have begun in the vicinity of the historical Pumpkin Spring aggregation 

(now often referred to as the JCM-west reach). By 2017, there was a clear signal of a substantial 

population of adult humpback chub present between Pumpkin Spring and Separation Canyon 

(~RM 210-240). Densities appear to diminish downriver from Separation Canyon (below ~RM 

240). Nevertheless, densities are still surprisingly high at some sites far downriver, such as at 

Columbine (~RM 273-275). USFWS and USGS are working collaboratively on an abundance 

estimate for humpback chub in western Grand Canyon (Van Haverbeke and others, in prep.) 

Additionally, we conducted opportunistic seining in 2021. We seined 91 backwaters between 

RM 35.6 and 269.2. Fish captures included 3,517 fish, of which 459 were humpback chub. Most 

humpback chub captured with seines were age 0 fish ≤ 70 mm. Seven nonnative species were 

captured, including five green sunfish (Lepomis cyanellus) captured at RM 159.3, RM 165.2 (3 

fish), and RM 199.5. We consider seining to be an important tool for early detection of juvenile 

nonnative fish. 

Figure 4. CPUEs of humpback chub (Gila cypha) and flannelmouth sucker (Catostomus latipinnis), all size classes, paired with 

total hoop nets set for each Grand Canyon aggregation trip 2000, and 2010-2021. Note in 2013 and 2014, two hoop netting 

aggregation trips [July (a), and September (b)] were conducted. Preliminary data, do not cite.
75

Element G.6. Juvenile Humpback Chub Monitoring – West

Science Questions/Hypotheses Addressed 

Humpback chub in western Grand Canyon are a relatively new component of humpback chub 

population in Grand Canyon, and little is known about their vital rates (survival, growth, 

movement, recruitment, abundance). 

• How do survival rates of humpback chub in western Grand Canyon compare to those of

the Little Colorado River aggregation? 

• What are humpback chub abundances in western Grand Canyon and what do they imply

for population trends? 

Results 

The JCM-west reach (located 210.5-214 river miles downstream of Lees Ferry) was sampled 

three times (May, July, and October) in 2022 by USGS. JCM trips visited the JCM-west reach 

(RM 210.5-214) after completing JCM-east sampling during the earlier portion of the trip. 

Sampling methods were similar for JCM-west and JCM-east reach (see Project Element G.3), 

and data presented are provisional and have not been subjected to full quality control. Species 

composition of catch in JCM-west was comprised mostly of native species, with the highest 

catch occurring for flannelmouth sucker (7008), speckled dace (5109), humpback chub (3105), 

and bluehead sucker (1442). Nonnative catch was comprised of fathead minnow (103), rainbow 

trout (53), common carp (15), green sunfish (12), striped bass (Morone saxatilis) (5), brown 

trout (5), walleye (Sander vitreus) (2), plains killifish (2), yellow bullhead (1), and black bullhead 

(1). In the JCM-west reach, catch of humpback chub > 79 mm TL was 222 in May, 240 in July, 

and 417 in October. In addition, the number of humpback chub issued VIE marks between 40-

79 mm TL was 45 in May, 139 in July, and 1295 in October. In 2022, we wrote a manuscript 

describing humpback chub population dynamics in the JCM-west reach from 2017-2021 that we 

will submit to a scientific journal early in FY 2023 (Dzul and others, in prep). 

Element G.7. Chute Falls Translocations 

Science Questions/Hypotheses Addressed 

The goals of this project, conducted by the USFWS, are to evaluate the potential for 

translocations to increase/maintain adult abundance in the Little Colorado River aggregation, 

by increasing growth, survival, and expanding the geographic distribution of humpback chub. 

This project is identified as a Conservation Measure in the LTEMP Biological Opinion (U.S. 

Department of the Interior, 2016b). These monitoring activities also coincide with collaborative 

efforts with the National Park Service (NPS) to collect juvenile or larval HBC for transport to the 

Southwest Native Aquatic Research and Recovery Center (SNARRC). 

Results 

Project Element G.7 annually translocates at least 300 juvenile humpback chub from lower 

portions of the Little Colorado River to upstream of rkm 14.2 (i.e., upstream of Chute Falls), and 

annually monitors the abundance of humpback chub upstream of rkm 13.6 in the Little 

Colorado River to evaluate the effectiveness of translocations. 
76

Efforts to translocate humpback chub upstream of Chute Falls in the Little Colorado River have 

been ongoing since 2003. To date (as of October 28, 2022), approximately 4,874 juvenile 

humpback chub have been translocated upstream of Chute Falls. Of these, 198 were released 

above Chute Falls (at rkm 16.2) on October 28, 2022. No fish were collected for translocations 

into Havasu, Bright Angel, or Shinumo Creeks during 2022, given perceived low young-of-year 

(YOY) production (lack of fish available). In May 2022, it was estimated there were 572 

humpback chub ≥ 100 mm (SE = 25) in the Atomizer reach (~rkm 13.6-14.1), of which 307 (SE = 

15) were ≥ 200 mm (Figure 11-A). Likewise, in May 2022, it was estimated there were 621 

humpback chub ≥ 100 mm (SE = 99) in the Chute Falls sample reach (~rkm 14.1-17.6), of which 

379 (SE = 48) were ≥ 200 mm (Figure 5). Humpback chub translocations have been found to 

provide modest increases to adult humpback chub abundances and, in some situations, may 

provide a good alternative to trout removals (Yackulic and others, 2021) 

Figure 5. Numbers of juvenile humpback chub translocated to the Chute Falls (rkm 14.1-17.7) reach since 2003 (black bars); 

and abundances of adult humpback chub ≥ 200 mm in the Chute Falls reach estimated with Chapman Petersen method (red 

bars), and Monte Carlo simulation (light gray bars). Preliminary data, do not cite.

References

Douglas, M.E., and Marsh, P.C., 1996, Population estimates/population movements of Gila 

cypha, an endangered cyprinid fish in the Grand Canyon region of Arizona: Copeia, v. 1996, 

no. 1, p. 15-28, https://doi.org/10.2307/1446938. 

Dzul, M.C., Yackulic, C.B., Giardina, M., Yard, M., Van Haverbeke, D.R., in prep, Vital rates of a 

burgeoning population of humpback chub in western Grand Canyon.
77

U.S. Department of Interior, 2016a, Record of Decision for the Glen Canyon Dam Long-Term 

Experimental and Management Plan final Environmental Impact Statement (LTEMP ROD): 

Salt Lake City, Utah, U.S. Department of the Interior, Bureau of Reclamation, Upper 

Colorado Region, National Park Service, Intermountain Region, 196 p., 

http://ltempeis.anl.gov/documents/docs/LTEMP_ROD.pdf. 

U.S. Department of the Interior, 2016b, U.S. Fish and Wildlife Service Biological Opinion 

(BiOp)—Appendix E, in Record of Decision (ROD) for the Glen Canyon Dam Long-term 

Experimental Plan final Environmental Impact Statement (LTEMP FEIS): Salt Lake City, Utah, 

Bureau of Reclamation, Upper Colorado Region, National Park Service, Intermountain 

Region, p. E-1—E-94, http://ltempeis.anl.gov/documents/docs/LTEMP_ROD.pdf. 

Valdez, R.A., and Ryel, R.J., 1995, Life history and ecology of the humpback chub (Gila cypha) in 

the Colorado River, Grand Canyon, Arizona—final report to Bureau of Reclamation: Salt 

Lake City, Utah, BIO/WEST, Inc., BIO/WEST report no. TR-250-08, Contract no. 0-CS-40-

09110, 328 p. plus appendices. (Available upon request from GCMRC)

Yackulic, C.B., Van Haverbeke, D.R., Dzul, M.C., Bair, L.S., and Young, K.L., 2021, Assessing the 

population impacts and cost-effectiveness of a conservation translocation: Journal of 

Applied Ecology, v. 58, no. 8, p. 1602-1612, https://doi.org/10.1111/1365-2664.13908. 

Project G Budget

Project G Deliverables: Humpback Chub Population Dynamics throughout the 

Colorado River Ecosystem

Presentations:

Bair, L.S., 2022, Adaptive management and cultural ecosystem services—virtual presentation: 

ACES, A Community on Ecosystem Services Conference, December 2022.

Burden

12.326%

Budgeted

Amount $343,451 $4,000 $79,500 $520,766 $0 $68,249 $1,015,966 

Actual

Spent $316,378 $1,731 $75,153 $520,766 $0 $64,097 $978,126 

(Over)/Under

Budget $27,073 $2,269 $4,347 $0 $0 $4,152 $37,840 

FY21 Unspent Funds $0 FY22 Unspent Funds $37,840

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

- Underspent Salaries is due to HR-delays in filling positions and staff turnover. 

- Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Underspent in Operating Expenses due to Pit Tags being purchased through BOR instead of the project.

Project G Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
78

Bair, L.S., 2022, Consideration of plural values in integrated assessments—presentation: AGU 

Chapman Conference, on ‘Solving Water Availability Challenges through an Interdisciplinary 

Framework’, September 12-16, 2022.

Dzul, M.C., and Yackulic, C.B., 2022, Effects of flow, sediment, and nonnative fishes on age-0 

population dynamics of humpback chub in the lower Little Colorado River—presentation: 

16th Biennial Conference of Science and Management for the Colorado Plateau and 

Southwest Region, September 12-15, 2022, Flagstaff, AZ.

Journal Articles:

Donovan, P., Reimer, M.N., Springborn, M.R., Yackulic, C.B., Bain, D.M., Bair. L.S., in prep, The 

economic cost of designer flows in river conservation. 

Dzul, M.C., Yackulic, C.B., Giardina, M., Yard, M., Van Haverbeke, D.R., in prep, Vital rates of a 

burgeoning population of humpback chub in western Grand Canyon.

Van Haverbeke, D.R., Dzul, M.C., Yackulic, C.B., Young, K.L., in prep, Abundance estimation of a 

recent prodigious humpback chub population in western Grand Canyon. 

USFWS Reports:

Van Haverbeke, D.R., Young, K.L., Pillow, M.J., and Rinker, P.N., 2022, Mark-recapture and fish 

monitoring activities in the Little Colorado River in Grand Canyon from 2000 to 2021: 

Flagstaff, Ariz., U.S. Fish and Wildlife Service, submitted to U.S. Geological Survey Grand 

Canyon Monitoring and Research Center, 49 p. 

Van Haverbeke, D.R., K.L. Young, M.J. Pillow, and Rinker, P.N., 2022, Monitoring humpback 

chub in the Colorado River, Grand Canyon during fall 2021: Flagstaff, Ariz., U.S. Fish and 

Wildlife Service, USFWS Document no. USFWS-AZFWCO-22-04, 41 p.
79

Project H: Salmonid Research and Monitoring 

 Goals and Objectives

This project is designed to evaluate the response of rainbow trout (Oncorhynchus mykiss) and 

brown trout (Salmo trutta) to both experimental flows and broad scale changes in 

environmental conditions, including water-quality. Work done as part of this project informs 

our understanding of how fish populations in Lees Ferry respond to experimental flows outlined 

in the LTEMP including High-Flow Experiments (HFEs), equalization flows, and 

Macroinvertebrate Production Flows (Bug Flows), as well as other management actions like the 

incentivized harvest program to decrease Lees Ferry brown trout populations (Runge and 

others, 2018). Project H has been divided into four project elements. Here, we report annual 

catch and community science data associated with trout monitoring in Glen Canyon (H.1), 

catch, fish condition and reproductive condition from the mark-recapture reaches in Lees Ferry 

(H.2), brown trout early life stage survey results (H.3), and ongoing population modeling (H.4) 

developed from data collected primarily through H.2. 

Project Elements

Element H.1. Rainbow Trout Monitoring in Glen Canyon (Arizona Game and Fish Department; 

AZGFD) 

Science Questions/Hypotheses Addressed

The goal of this monitoring effort is to assess the status and trends of rainbow trout abundance 

and distribution in the Colorado River reach between Glen Canyon Dam and Lees Ferry, and to 

monitor angler use of the Lees Ferry fishery. We use three approaches to monitor the Lees 

Ferry trout fishery: 1) boat electrofishing, 2) angler surveys (creel) including the use of a game 

camera, and 3) a community science program with angling guides and private anglers that 

measure captured fish.

Methods

We conduct boat electrofishing at randomly selected 250-meter (m) sites to obtain a 

representative sample of the fish assemblage within the Lees Ferry reach. 

Project Lead Charles Yackulic

Principal 

Investigator(s) (PI)

Charles Yackulic, USGS, GCMRC

Josh Korman, Ecometric Research

Mariah Giardina, USGS, GCMRC

David Rogowski, AZGFD

David Ward, USGS, GCMRC

Molly A.H. Webb, USFWS

James A. Crossman, BC Hydro

Email cyackulic@usgs.gov

Telephone (928) 556-7379
80

Our objectives are to gather long-term trend data on relative abundance using catch-per-uniteffort (CPUE) methods, population structure (size composition), distribution, growth rate, 

relative condition, and overall recruitment to reproductive size. In addition, we conducted one 

night of warm water nonnative sampling during summer and autumn sampling trips to detect 

warm-water nonnative species, as described in Project Element I.2. 

To estimate angler use, we conduct angler surveys to obtain a representative sample of the 

recreational angling community at Lees Ferry. Arizona Game and Fish Department (AZGFD) uses 

stratified random sampling to select six days/month for interviews of both boat (access point 

creel at boat ramp) and shoreline anglers (roving creel). Information obtained includes, but is 

not limited to, catch rates, gear type, species composition, harvest, and satisfaction with 

angling experience. Since June 2015, a game camera has been installed at Lees Ferry to record 

images of the boat launch area and provide a better estimate of boat anglers for the days and 

hours when a technician is not present.

The community science program is an attempt to quantify the lengths of fish captured by 

anglers. Length-related angler catch metrics are included in the Lees Ferry fisheries 

management plan but cannot be determined from angler surveys.

Results

Electrofishing

AZGFD completed three monitoring trips in 2022, sampling 120 sites and capturing 1,429 fish 

(excluding the nonnative sampling); 873 rainbow trout (Oncorhynchus mykiss), 377 brown trout

(Salmo trutta), 105 flannelmouth sucker (Catostomus latipinnis), 14 smallmouth bass

(Micropterus dolomieu), three black crappie (Pomoxis nigromaculatus), two common carp

(Cyprinus carpio), and two green sunfish (Lepomis cyanellus). Rainbow trout CPUE (0.87 

fish/minute [0.75, 0.98]) was similar to 2021 (0.87 fish/minute [0.70, 1.0]) and continues to be 

the lowest we have observed since monitoring began in 1991 (Figure 1). Rainbow trout 

comprised 61.2% of our 2022 catch, and this is the lowest percentage of the fish assemblage we 

have ever measured. Brown trout CPUE (0.37 fish/minute [0.30,0.44]) was similar to 2021 (0.34 

fish/minute [0.28, 0.42]). Brown trout catch rates for 2020-2022 have been higher than all 

previous years, with brown trout comprising 26.6% of our 2022 catch (Figure 2). Relative 

abundance of rainbow trout, as measured by electrofishing CPUE, has fluctuated greatly since 

AZGFD began standardized sampling in 1991 (Figure 1). However, from 2019 – 2022, rainbow 

trout CPUE declined, particularly among smaller size classes (< 152 mm, 152 mm – 305 mm). 

Large rainbow trout (> 306 mm) are less abundant than other size classes, but CPUE has 

remained relatively steady since 2016 (Figure 3). In fall, young of year accounted for 67% of the 

rainbow trout catch (compared to 74% in 2021), with a CPUE of 0.54 fish/hour (lower than 2021 

at 0.75 fish/hour). Although rainbow trout abundance was low, the fish we captured showed a 

high relative condition in 2022, which was greater than 1.0 for all size classes across all 

sampling trips.
81

Figure 1. Average catch-per-unit-effort (fish/minute) of rainbow trout at Lees Ferry from Arizona Game and Fish Department’s 

standardized monitoring (electrofishing) by year.

Figure 2. Mean catch-per-unit-effort (fish/minute) of brown trout captured during Arizona Game and Fish Department’s 

monitoring at Lees Ferry by year. This represents the average across all size classes and reaches sampled. 
82

.

Figure 3. Average catch-per-unit-effort (fish/minute) of rainbow trout at Lees Ferry from Arizona Game and Fish Department’s 

standardized monitoring (electrofishing) by size class and year.

Angler Surveys (Creel)

We report on creel data on a calendar year cycle and data collection is ongoing. For this report, 

we present data from January through early October 2022. We conducted angler surveys on 58 

days and interviewed 595 boat anglers and 94 walk-in anglers. Angler catches rates (CPUE) for 

rainbow trout in 2022 for boat anglers was 0.74 fish/hour, and for walk-in anglers it was 0.52 

fish/hour. Angler catch rates are below the AZGFD management goal for an angler catch rate of 

≥ one rainbow trout per hour. Seventy percent of boat anglers and 38% of walk-in anglers 

caught at least one fish. Despite the low catch rates, angler satisfaction on a scale of 1-5 

remained similar for walk-in anglers in 2022 (3.3) compared to 2021 (3.4). Boat angler 

satisfaction increased in 2022 (3.8) from 2021 (3.6). Although an incentivized harvest program 

for brown trout was implemented, harvest rates for brown trout were only 25% for boat 

anglers. Only four brown trout were captured in the walk-in area, and all were harvested. In 

2022, 59% of unique anglers interviewed knew about the incentivized harvest program, and of 

those, 46% said they would participate. However, only 85 of 670 (12%) anglers interviewed 

captured a brown trout, and only 28 anglers harvested a brown trout. 33% of anglers that 

captured a brown trout harvested a brown trout. 
83

Community Science Program

Data collection for this project is ongoing. For this report, we present data from January 

through September of 2022. Citizen scientists submitted length data on 719 rainbow trout and 

50 brown trout captured. These data came from six private anglers with a total of 79 unique 

trips. These data are not representative of all anglers, as 70% percent of the angler trips were 

from one angler. Rainbow trout captured by citizen scientists had a mean length of 13.2 inches 

[13.2, 13.3] (337 mm [334, 339]), and brown trout had a mean total length of 16.7 inches [14.4, 

16.4] (424 mm [404, 443]). Rainbow trout captured in 2022 were on average larger than those 

captured in 2021 (12.1 inches, 308 mm). Based on citizen science data, the rainbow trout 

fishery at Lees Ferry was not meeting AZGFD management goals for quality size fish; only 37% 

of angler trips resulted in anglers catching ten 14” rainbow trout in a 10-hour day (based on 

CPUE), and no angler trips caught rainbow trout 20” or greater (out of 79 trips). 

Element H.2. Experimental Flow Assessment of Trout Recruitment (TRGD Project)

Research Objectives Addressed

This research is referred to as the Trout Recruitment and Growth Dynamics (TRGD) project, and 

it is designed to collect data that is used to determine the impacts of environmental conditions 

and experimental flows on the recruitment of young-of-year (YOY) rainbow trout and brown 

trout in Glen Canyon, the growth rates of juvenile and adult trout, and dispersal of YOY trout 

from Glen Canyon to Marble Canyon. TRGD was established in the FY 2018-20 Triennial Work 

Plan (TWP; U.S. Department of the Interior, 2017) with three subreaches from Glen Canyon 

Dam to Lees Ferry, each with an assigned 3-km length. Due to budget constraints in the FY 

2021-23 TWP, sampling effort was reduced to two subreaches (1A, 1C). The two remaining 

subreaches are in the upper (circa -12 RM) and lower (circa ~-4 RM) portions of Glen Canyon 

and represent 24% of the total shoreline length of Glen Canyon. The lowest subreach (1C) has 

been sampled since 2012, which allows for long term analyses (comparisons and contrasts) that 

integrate the Natal Origins (NO) Project (2011-2017; FY 2015-17 TWP; U.S. Department of the 

Interior, 2014) and more recent work plans (FY 2018-20 TWP), which informs both brown and 

rainbow trout models (Project Element H.4). During FY 2021-23, an additional focus of this 

project is on developing field techniques to measure reproductive condition more accurately in 

salmonids, with the potential to extend these noninvasive methods to native fish species once 

they have been refined. This element also involves sampling in Marble Canyon intended to 

inform our understanding of rainbow trout emigration from Lees Ferry.

Results

TRGD Sampling in Lees Ferry

In 2022, subreaches 1A and 1C were sampled in the months of January, April, September, and 

November, and subreach 1C was sampled a fifth time in June. Each sampling trip consisted of a

2-pass mark-recapture methodology using electrofishing as the gear type. 
84

A total of 16,998 fish (rainbow trout [10,944]; brown trout [4,459]; flannelmouth sucker [1013]; 

green sunfish [446]; smallmouth bass [69]; bluegill sunfish [Lepomis macrochirus; 34]; common 

carp [28], black crappie [3]; bluehead sucker [Catostomus discobolus; 1] and walleye [Sander 

vitreus; 1]) were captured by electrofishing in 2022. 

Rainbow trout catch in 2022 was low compared to historical data but was similar to 2021 catch 

(Figure 4). Brown trout catch remained relatively high in 2022 (compared to historical data for 

this species) but was lower than 2021 catch during the September and November trips (Figure 

5). In particular, the fall catch of YOY brown trout (< 75 mm) was lower than in 2020 and 2021, 

suggesting lower brown trout recruitment in 2022. These declines in fall brown trout catch, 

while modest, coincided with the four warmest months in terms of water temperatures in the 

last fifty years, and dissolved oxygen was extremely low (with daily averages dropping below 

3mg/L and point measurements as low as 2 mg/L) during this period (USGS gage 09380000; U.S. 

Geological Survey, 2022). These data could indicate either lower capture probability at warmer 

temperatures or a decline in the overall population. 

Ongoing brown trout modeling under Element H.4 is attempting to disentangle these impacts. 

Past research has shown that changes in the condition of rainbow trout often precede 

population declines (Korman and others, 2016; Korman and others, 2017; Korman and others, 

2020), and recent declines in the condition of both rainbow and brown trout during the four 

months of elevated temperatures (Figure 6) suggest the potential for future declines in 

abundance of both species. The decline in condition of brown trout was particularly notable, 

consistent with the decline in catch of brown trout. Analysis of rainbow and brown trout 

capture-recapture data under H.4 will occur over the next few months after the data have been

processed . 

While the Glen Canyon catch was dominated by salmonids, warm-water nonnatives like 

smallmouth bass, bluegill sunfish, and green sunfish increased substantially over the course of 

the year (from zero in 2021 to 69 in 2022 for smallmouth bass, zero in 2021 to 34 in 2022 for 

bluegill sunfish, and 15 in 2021 to 446 in 2022 for green sunfish). Sampling in both September 

and November suggested that abundances of warm-water nonnative species are higher in areas 

of Lees Ferry that are closest to the dam (e.g., 64 smallmouth bass have been captured in 

subreach 1A, which is within 3 miles of the dam, as compared to five smallmouth bass captured

downstream in subreach 1C, which is more than 10 miles from the dam).
85

Figure 4. Rainbow trout catch per kilometer of shoreline over time in each subreach by size classes (colors). Preliminary data, 

do not cite.

Figure 5. Brown trout catch per kilometer of shoreline over time in each subreach by size classes (colors). Preliminary data, do 

not cite.
86

Figure 6. Relative condition factor for rainbow trout (circular symbol) and brown trout (diamond symbol) from electrofishing data 

collected in Glen Canyon between September 2015 and November 2022 for fish with a fork length of 275 mm or greater (April 

2020 was cancelled due to COVID, no data). Points show the median value and error bars show 80% credible interval. Note that 

relative condition factor for brown trout is calculated using the equation for rainbow trout, for comparison purposes. Preliminary 

data, do not cite.

Reproductive Condition Research

Condition factor of rainbow trout in the fall is a good predictor of an index of sexual maturation 

rates the following winter and spring (Yard and Korman, 2020; Crossman and others, 2022). 

Condition factor is higher when growth is higher, potentially leading in turn to an increase in 

the proportion of trout that reach sexual maturity and spawn. Understanding the relationship 

between condition-affected sexual maturation and recruitment may help us develop a more 

reliable method for forecasting and responding to small or large recruitment events. Current 

methods to evaluate sexual maturity in the field are relatively crude, relying on estimates of the 

proportion of fish that express gametes when manipulated. This approach is known to lead to a 

substantial bias in sex ratios (i.e., males express gametes more readily than females), and it is 

the uncertainty of whether or not the percentage of males or females expressing gametes each 

year is proportional to the actual percentage of adults that spawn and contribute to 

recruitment. 

In the FY 2018-20 TWP we conducted a detailed study to quantify season-, size-, and sexspecific variation in rainbow trout population reproductive structure based on histological 

analyses of gonad tissue. A secondary objective was to use the histological assignment of 

reproductive stage to determine the accuracy of nonlethal methods (manual expression and 

ultrasonography) for assigning sex. This work was published (Crossman and others, 2022), and 

results found that some of the larger male trout that would be expected to be reproductive are 

not, and overall, a surprisingly large proportion of adult fish are not reproductive. Rates of 

atresia (degeneration of ovarian follicles) in females was highest in the fall. 
87

We suspect these patterns in rainbow trout were the result of low growth rates due to limited 

prey availability and high levels of competition. Correct sex assignment using ultrasonography 

was significantly higher for rainbows in spawning condition compared to immature fish, and 

reproductive females (100% accuracy) had higher accuracy than males (77%). Objectives of the 

reproductive work started in the FY 2018-20 TWP were then expanded to brown trout in FY 

2021-22 with the goal of comparing reproductive structure between the two species and 

further expanding the application of ultrasonography to understand the accuracy in assigning 

reproductive condition to the spawning population of each species. 

Preliminary results show that based on size, like rainbow trout, a number of large brown trout 

that should be reproductive are not, a result which could be related to the declining condition 

in the population in recent years (Figure 6). Application of ultrasonography has been extremely 

successful with > 99% of trout > 275 mm scanned (n=1,116) on the November 2022 trip and 

assigned to a reproductive condition (specific reproductive stage for females). From the 

preliminary ultrasound data, rates of atresia appear to be high in rainbow trout in fall 2022. 

Work to compare the population reproductive structure between the two species and finalize a 

protocol for application of ultrasonography will be completed in 2023.

Outmigration from Lees Ferry

The abundance and persistence of rainbow trout near the Little Colorado River depends on 

both the numbers of juvenile trout that disperse from Glen Canyon and their subsequent 

survival and reproduction rates in Marble Canyon (Korman and others, 2016). Previous research 

has indicated it is likely that small trout move downstream and repopulate Marble Canyon 

during years when the Lees Ferry fishery has large recruitment (Yard and others, 2016; Korman 

and Yard, 2017; Korman and others, 2021). In 2022 we continued monitoring YOY trout 

populations in Marble Canyon and at the Little Colorado River by conducting sampling in 

association with the April, July, and October JCM trips (Project Element G.3). These data will be 

used to further understand dispersal dynamics relative to experimental flows, fish density, and 

other factors like nutrients that influence upstream trout populations.

Element H.3. Brown Trout Early Life Stage Survey in Glen Canyon 

The Brown Trout Early Life Stage Survey (BTELSS) objectives are to: 1) understand early life 

stage vital rates for YOY brown trout in Glen Canyon, 2) assess hatch and swim-up dates to 

identify when brown trout are likely to be emerging from gravel redds, and 3) identify habitat 

preferences for low angle (cobble bars, vegetated sandbars, debris fans) versus high angle 

(talus) nearshore habitat to understand stranding vulnerability to experimental flows.

 

The BTELSS project was implemented as part of Project Elements H.3 and O.6 in the FY 2021-23 

TWP. In 2021, we collected data to evaluate the effect of the Spring Disturbance Flow on early 

stages of brown trout, while 2022 served as a reference year. No additional data will be 

collected in 2023. From January 5 through May 12, 2022, we conducted six BTELSS trips spaced 

approximately 3-4 weeks apart. 
88

In total, we captured 1,635 fish, of which 98.5% were YOY or age-1 trout (rainbow trout [n=941, 

57.9%], brown trout [n=341, 21.0% of catch], unknown YOY trout [n=329, 20.3%]), and green 

sunfish [n=24, 1.5%]. We notably captured more green sunfish in 2022 than 2021 (n=5). Of the 

identifiable trout species in 2022, 27% were brown trout and 73% were rainbow trout. A large 

portion of the YOY trout in 2021 and 2022 were not field-identifiable (i.e., too small to 

distinguish in the field or had morphological characteristics of both species), so we sent those 

specimens to the American Southwest Ichthyological Researchers (ASIR) for positive

identification and to develop a field key. In 2021, 252 of 342 specimens could be identified; 90 

specimens were too degraded to assign species status. 

All specimens were identified as rainbow trout; no YOY brown trout were identified in 2021. 

The 2021 results were available mid-field season in 2022, so we modified our sampling design

in the last three trips to use different methods of capture (e.g., minnow traps - baited and 

unbaited - light traps, seines), sampling times (day and night), and different field locations 

(including backwaters) to further examine habitats that may be utilized by YOY brown trout in 

Glen Canyon. Of the 329 unidentified YOY trout in 2022, 16 specimens were identified as brown 

trout. YOY brown trout were only captured in the last two trips of the year (March 30-April 1, 

May 10-12, 2022), with most captures on cobble bars near -4.1 and -10.8 RM. 

We sent 28 YOY or age-1 brown trout collected between 2016-2022 to ASIR for age 

determination and back-calculation of hatch dates (Figure 1a). Specimens ranged from 38-108 

days post-hatch, with hatch dates ranging from January 30 to April 13. The embryos in this data

set incubated for 45-53 days prior to hatching, indicating brown trout have a protracted 

spawning season that spans fall to early spring. Median hatch date was March 13, with the 

majority of brown trout hatching in the second week of March (Figure 1b). Preliminary results 

indicate a strong positive relationship (r = 0.939, P < 0.0001) between otolith age and standard 

length (mm) of fish, with a rapid rate of growth from 0.42 mm/d to 0.64 mm/d. 

Figure 1. a) Sagittal otolith of a brown trout at 200x magnification. The red arrow indicates the hatch check. Age counts are 

determined by counting increments between the hatch check and the edge of the otolith. b) Hatch date distribution by week for 

YOY or age-1 brown trout in the Colorado River (Lees Ferry) captured between 2016-2022.
89

Element H.4. Salmonid Modeling

Science Questions/Hypotheses Addressed

The goal of Element H.4 is to analyze field data on salmonid populations collected in Project 

Elements H.1, H.2, and G.3 to estimate the efficacy of ongoing management actions and 

improve our capacity for predicting impacts of future management actions. Specifically, we 

identify four areas of research in this work plan: 1) reassess the causal hypotheses explored in 

Runge and others (2018) using data collected in recent years, 2) estimate the efficacy of 

incentivized harvest of brown trout by modifying the existing brown trout model to incorporate 

harvest data to inform managers and improve design of incentives (Project J), 3) estimate 

population dynamics of rainbow trout in the Lees Ferry reach in response to experimental flows 

and other drivers, and 4) continue development of a simple integrated model to predict 

recruitment and outmigration of rainbow trout using multiple data sources over nearly a 20-

year period.

Results

Modeling in all four areas of research is progressing but has been slowed by the requests to 

divert staff attention to smallmouth bass issues and understaffing, included the loss of the 

principal investigator of Project H (Kimberly Dibble), who left for a different job. In 2022, we 

collaborated with National Park Service colleagues to finish two manuscripts that address 

brown trout movement in response to the use of a weir in Bright Angel creek and fall HFEs 

(Healy and others, 2022) and simulate potential response of brown trout to different 

management and climate change scenarios (Healy and others, 2022). In 2022, two modeling 

manuscripts focused on rainbow trout dynamics were also accepted for publication. The first 

manuscript estimated the impacts of both fall high-flow events (HFEs) and bug flows on 

rainbow trout growth and contrasted the effects of sizes of these designer flows with the 

expected impacts of declining reservoir levels (Korman and others, 2022). The second 

manuscript, developed in conjunction with Project E, integrated rainbow trout growth and 

abundance data with invertebrate drift data collected through Project F to estimate prey 

production in Lees Ferry, and show it was tightly linked to change in soluble reactive 

phosphorous concentrations in Lees Ferry (Yard and others, 2023). We have also made progress 

in modeling rainbow trout movement from an integrated model and plan to develop and 

submit a manuscript on this subject in 2023.

Results from the rainbow trout and brown trout models were reported at the January 2023 

reporting meeting as usual but were not available in time for this written report.

References

Crossman, J.A., Webb, M.A.H., Korman, J., and Yard, M.D., 2022, Population reproductive 

structure of rainbow trout determined by histology and advancing methods to assign sex 

and assess spawning capability: Transactions of the American Fisheries Society, v. 151, no. 

4, p. 422-440, https://doi.org/10.1002/tafs.10356. 
90

Healy, B., Budy, P., Yackulic, C., Murphy, B.P., Schelly, R.C., and McKinstry, M.C., 2022, Exploring 

metapopulation-scale suppression alternatives for a global invader in a river network 

experiencing climate change: Conservation Biology, v. 37, no. 1, e13993, p. 1-18, 

https://doi.org/10.1111/cobi.13993. 

Healy, B.D., Yackulic, C.B., and Schelly, R.C., 2022, Impeding access to tributary spawning 

habitat and releasing experimental fall-timed floods increases brown trout immigration into 

a dam's tailwater: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0231. 

Korman, J., Yard, M.D., and Yackulic, C.B., 2016, Factors controlling the abundance of rainbow 

trout in the Colorado River in Grand Canyon in a reach utilized by endangered humpback 

chub: Canadian Journal of Fisheries and Aquatic Sciences, v. 73, no. 1, p. 105-124, 

https://doi.org/10.1139/cjfas-2015-0101. 

Korman, J., and Yard, M.D., 2017, Effects of environmental covariates and density on the 

catchability of fish populations and interpretation of catch per unit effort trends: Fisheries 

Research, v. 189, p. 18-34, https://doi.org/10.1016/j.fishres.2017.01.005. 

Korman, J., Yard, M.D., and Kennedy, T.A., 2017, Trends in rainbow trout recruitment, 

abundance, survival, and growth during a boom-and-bust cycle in a tailwater fishery: 

Transactions of the American Fisheries Society, v. 146, no. 5, p. 1043-1057, 

https://doi.org/10.1080/00028487.2017.1317663. 

Korman, J., Yard, M.D., Dzul, M.C., Yackulic, C.B., Dodrill, M.J., Deemer, B.R., and Kennedy, T.A., 

2020, Changes in prey, turbidity, and competition reduce somatic growth and cause the 

collapse of a fish population: Ecological Monographs, v. 91, no. 1, e01427, p. 1-20, 

https://doi.org/10.1002/ecm.1427. 

Korman, J., Yard, M.D., Dzul, M.C., Yackulic, C.B., Dodrill, M.J., Deemer, B.R., and Kennedy, T.A., 

2021, Controls on somatic growth and population dynamics of rainbow trout: Bulletin of the 

Ecological Society of America, v. 102, no. 1, e01810, p. 1-6, 

https://doi.org/10.1002/bes2.1810. 

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related 

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Runge, M.C., Yackulic, C.B., Bair, L.S., Kennedy, T.A., Valdez, R.A., Ellsworth, C., Kershner, J.L., 

Rogers, R.S., Trammell, M., and Young, K.L., 2018, Brown trout in the Lees Ferry reach of the 

Colorado River—Evaluation of causal hypotheses and potential interventions: U.S. 

Geological Survey Open-File Report 2018-1069, 83 p., 

https://doi.org/10.3133/ofr20181069. 

U.S. Department of the Interior, 2014, Glen Canyon Adaptive Management Program Triennial 

Budget and Work Plan—Fiscal years 2015-2017: Bureau of Reclamation, Upper Colorado 

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

prepared in conjunction with the Glen Canyon Dam Adaptive Management Program, 475 p. 

plus appendices, https://www.usbr.gov/uc/progact/amp/amwg/2017-09-20-amwgmeeting/Attach_04a.pdf. 
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U.S. Department of the Interior, 2017, Glen Canyon Dam Adaptive Management Program 

Triennial Budget and Work Plan—Fiscal Years 2018-2020—Final submitted to the Secretary 

of the Interior: Flagstaff, Ariz., U.S. Geological Survey, Grand Canyon Monitoring and 

Research Center and Salt Lake City, Utah, Bureau of Reclamation, Upper Colorado Region, 

316 p.

U.S. Geological Survey, 2022, National Water Information System: U.S. Geological Survey web 

interface, https://doi.org/10.5066/F7P55KJN. Cited November 2022 at 

https://waterdata.usgs.gov/nwis. 

Yard, M.D., and Korman, J., 2020, TRGD—Trout recruitment, growth, and population 

dynamics—presentation to the Glen Canyon Dam Adaptive Management Program, Annual 

Reporting Meeting, January 14, 2020: Phoenix, Ariz., U.S. Geological Survey, Grand Canyon 

Monitoring and Research Center. 

Yard, M.D., Korman, J., Walters, C.J., and Kennedy, T.A., 2016, Seasonal and spatial patterns of 

growth of rainbow trout in the Colorado River in Grand Canyon, Arizona: Canadian Journal 

of Fisheries and Aquatic Sciences, v. 73, no. 1, p. 125-139, https://doi.org/10.1139/cjfas2015-0102. 

Yard, M.D., Yackulic, C.B., Korman, J., Dodrill, M.J., and Deemer, B.R., 2023, Declines in prey 

production during the collapse of a tailwater rainbow trout population are associated with 

changing reservoir conditions: Transactions of the American Fisheries Society, v. 152, no. 1, 

p. 35-50, https://doi.org/10.1002/tafs.10381. 

Yackulic, C.B., 2020, Predictions, populations, and energetic constraints—presentation to the 

Glen Canyon Dam Adaptive Management Program, Annual Reporting Meeting, January 13, 

2020: Phoenix, Ariz., U.S. Geological Survey, Grand Canyon Monitoring and Research 

Center. 

Project H Budget

Burden

12.326%

Budgeted

Amount $181,222 $11,700 $25,566 $148,000 $0 $31,371 $397,859 

Actual

Spent $123,423 $5,874 $68,077 $152,685 $0 $28,909 $378,968 

(Over)/Under

Budget $57,799 $5,826 ($42,511) ($4,685) $0 $2,462 $18,891 

FY21 Unspent Funds $0 FY22 Unspent Funds $18,891

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

-Underspent Salaries is due to HR-delays in filling positions and staff turnover. 

- Underspent in Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Overspent in Operating Expenses is due to change in funding mechanism for a cooperator from a Cooperative Agreement to a 

contract. 

-Overspent amount in Cooperative Agreement is additional funds sent to USFWS for eDNA analysis. 

Project H Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
92

Project H Deliverables: Salmonid Research and Monitoring

Journal Articles: 

Crossman, J.A., Webb, M.A.H., Korman, J., and Yard, M.D., 2022, Population reproductive 

structure of rainbow trout determined by histology and advancing methods to assign sex 

and assess spawning capability: Transactions of the American Fisheries Society, v. 151, no. 

4, p. 422-440, https://doi.org/10.1002/tafs.10356. 

Healy, B., Budy, P., Yackulic, C., Murphy, B.P., Schelly, R.C., and McKinstry, M.C., 2022, Exploring 

metapopulation-scale suppression alternatives for a global invader in a river network 

experiencing climate change: Conservation Biology, v. 37, no. 1, e13993, p. 1-18, 

https://doi.org/10.1111/cobi.13993. 

Healy, B.D., Yackulic, C.B., and Schelly, R.C., 2022, Impeding access to tributary spawning 

habitat and releasing experimental fall-timed floods increases brown trout immigration into 

a dam's tailwater: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0231. 

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related 

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Yard, M.D., Yackulic, C.B., Korman, J., Dodrill, M.J., and Deemer, B.R., 2023, Declines in prey 

production during the collapse of a tailwater rainbow trout population are associated with 

changing reservoir conditions: Transactions of the American Fisheries Society, v. 152, no. 1, 

p. 35-50, https://doi.org/10.1002/tafs.10381. 

USGS Reports: 

Giardina, M.A., Korman, J., Yard, M., Wright, S., Kaplinski, M., and Bennett, G., in final edits with 

the USGS Science Publishing Network, A literature review and hypsometric analysis to 

support decisions on trout management flows on the Colorado River downstream from 

Glen Canyon Dam: U.S. Geological Survey Open-File Report.

USGS Data Releases: 

Yackulic, C.B., Yard, M., Korman, J., Rogowski, D., Healy, B.D., Schelly, R.C., Omana-Smith, E., 

and Nelson, C., 2022, Brown trout movement data in Glen and Grand canyons, Arizona, 

USA: U.S. Geological Survey data release, https://doi.org/10.5066/P96NII4B. 
93

Project I: Warm-Water Native and Nonnative Fish Research 

and Monitoring

Goals and Objectives 

This project continues long-term, standardized monitoring conducted by the Arizona Game and 

Fish Department (AZGFD) throughout the Colorado River from Lees Ferry (River Mile (RM) 0) to 

Pearce Ferry (RM 281) for the combined purposes of tracking the status of native fish as well as 

identifying new invasive aquatic species (system wide native fish and aquatic invasive species 

monitoring). This project also provides detection capability for new warm-water invasive fish, 

which may be entering the Colorado River ecosystem (CRe) from Lake Powell by passing 

through Glen Canyon Dam, descending tributaries such as the Little Colorado River, or 

swimming upstream from Lake Mead (improve early detection of warm-water invasive fish). 

Nonnative fish typically have detrimental impacts on the stability of native fish communities 

(Marsh and Pacey, 2005; Erős and others, 2020). Identifying sources of warm-water invasive 

fish in the CRe early improves the likelihood that a successful rapid containment/eradication 

response can be accomplished before negative impacts on endangered populations occur 

(Martinez and others, 2014). In addition, this project quantifies the potential negative impacts 

of nonnative fish and fish parasites on native fish populations both in the field by collecting diet 

and abundance information as well as in the laboratory by quantifying predation risk of 

nonnative fish in replicated laboratory trials (assess the risks warm-water nonnative fish pose to 

native fish). 

 

The primary goal of the system wide monitoring program (Element I.1 of this project) is to 

monitor the status and trends of native and nonnative fish in the Colorado River from Lees 

Ferry to Lake Mead. The AZGFD randomly samples selected reaches and sites throughout the 

Colorado River in Grand Canyon using boat electrofishing, baited hoop nets, and angling to 

obtain a representative sample of the fish assemblage. Species composition and relative 

abundance (catch-per-unit effort (CPUE)) are used to interpret trends in abundance and 

distribution of native and nonnative fish throughout Grand Canyon. Trends in CPUE over time 

for system wide native and nonnative fish are calculated by examining deviations in the mean 

catch among years, compared with the calculated 95% confidence interval of catch rate for a 

given year. 

Project Lead David Ward

Principal 

Investigator(s) (PI)

David Ward, USGS, GCMRC

David Rogowski, AZGFD

Kirk Young, USFWS

Kimberly Dibble, NPS (formerly with 

USGS, GCMRC)

Charles Yackulic, USGS, GCMRC

Email dlward@usgs.gov

Telephone (928) 556-7280
94

Although CPUE trends can be biased if capture probability is not consistent, consecutive years 

of catch rates above or below the 95% confidence interval of the mean would indicate a 

significant trend. Additionally, because of the broad nature of our sampling (i.e., multispecies, 

geographically broad), we are also able to use our monitoring data to provide information 

related to emerging management concerns or questions. 

Element I.2. is focused on improving early detection of warm-water invasive fish. To improve 

early detection of rare, nonnative species in Glen Canyon, AZGFD conducts rare nonnative 

monitoring twice a year (summer and autumn). The primary goal of the rare nonnative 

monitoring is to provide early detection of rare nonnative fish species in Glen Canyon. AZGFD 

targets areas where rare nonnatives have been caught before and warmer water areas such as 

spring inflows and sloughs/backwaters. In addition, GCMRC is conducting an eDNA project. The 

objective of the eDNA project is to detect rare native and nonnative species by filtering DNA 

from the water. Fish shed scales, mucous, and other products are shed into the water, allowing 

researchers to collect that DNA via filtration to determine whether a species is present. Since 

the quantity of eDNA in a sample linearly scales with fish biomass, relative abundance metrics 

can be calculated using quantitative Polymerase Chain Reaction (PCR) and standard curves 

(Klymus and others, 2015). These efforts to improve early detection of invasive warm-water fish 

will be used to direct future monitoring efforts or emergency responses as needed. 

The goal for Element I.3 of this project is to evaluate impacts of invasive nonnative warm-water 

fish on humpback chub (Gila cypha) in both laboratory and field settings. Our objective is to 

quantify the relative risks that each warm-water predator poses to native fish. The risks of 

predation on humpback chub by existing predators such as channel catfish (Ictalurus 

punctatus), common carp (Cyprinus carpio), and green sunfish (Lepomis cyanellus) need to be 

quantified. The potential impact of smallmouth bass (Micropterus dolomieu), which are not yet 

established in the CRe but are likely to become established, have also not been quantified. Our 

goal is to evaluate the relative predation vulnerability of humpback chub to these predatory 

warm-water species using methods similar to those employed for past trials with rainbow and 

brown trout (Ward and Morton-Starner, 2015). Standardized methods allow comparison of 

relative predation risks. These data will allow managers to understand which warm-water 

invasive fish are the most detrimental to humpback chub populations so that management 

efforts can be focused on those species that are the most problematic.

Science Questions Addressed & Results

Project Elements 

Element I.1. System-Wide Native Fish and Invasive Aquatic Species Monitoring

Science Question

• What is the species composition, relative abundance, longitudinal distribution, and 

population trends of the fish assemblage inhabiting the CRe? 
95

Results

AZGFD completed two mainstem sampling trips in 2022 to continue our long-term monitoring 

and describe the relative abundance and distribution of native and nonnative fish throughout 

the Colorado River in Grand Canyon. On the spring trip (April 1-14, RM 0 - 281), we captured 

1,113 fish at 166 electrofishing sites, 2802 fish in 166 baited hoop nets, and 22 fish with 13 

evenings of angling. Turbidity during the spring trip was high downstream of the Little Colorado 

River, so we reduced the number of electrofishing sites and increased the number of hoop nets 

set downstream of the Little Colorado River. During the autumn sampling trip (Nov 1-4) we 

sampled upstream of Pearce Ferry Rapid (RM 271 - 281.5). Due to the low water, shifting 

sandbars, and turbidity, electrofishing at night was deemed too dangerous during our autumn 

trip, thus we only electrofished one night. We captured 13 fish at 14 electrofishing sites, 483 

fish in 56 hoop net sets, and no fish at three angling sites.

Over the 23 years of AZGFD monitoring, relative abundance of most nonnative species has 

decreased, and abundance of most native species has increased. This year, we observed similar 

fish distribution patterns to recent years (e.g., 2016-present), with nonnative rainbow trout 

comprising most (89.4%) of the electrofishing catch in Marble Canyon, and native fish 

comprising most of the catch (98.7%) downstream of the Little Colorado River confluence. 

Rainbow trout (Oncorhynchus mykiss) and flannelmouth sucker (Catostomous latippinis) were 

the most captured species during our spring monitoring this year (44.9 and 43.8% of 

electrofishing catch, respectively). Rainbow trout appeared to compromise a greater 

percentage of the fish assemblage captured by electrofishing this year because of reduced 

electrofishing downstream of the Little Colorado River in response to high turbidity. 

Results from hoop nets sampling in 2023 reveal a similar number of fish over the past three 

years (Figure 1). Flannelmouth sucker were the most common species (85.9%) captured in hoop 

nets in spring of 2022, and the only native fish captured throughout the entire canyon. This 

year (2022), we observed a higher CPUE of flannelmouth sucker in reaches of Marble Canyon as 

well as in Glen Canyon than in previous years. In our autumn sampling for the first time, 

humpback chub were the most common species captured in hoop nets, comprising 62.1% of 

our catch. Only 20% of humpback chub captured in the autumn were previously tagged, 

compared to 34% during our spring monitoring. 

Each gear type has certain biases and targets different species. Angling targets channel catfish, 

and in the past has been a productive method of capturing numerous channel catfish. In recent 

years we rarely captured channel catfish angling (0-1), and this year was no exception; we 

didn’t catch any. This year humpback chub were the most common species captured angling 

(n=17). We also captured four rainbow trout, and one common carp. 
96

Figure 1. Catch-per-unit effort (fish/net night) with 95% CI of native fish from baited hoop nets from AZGFD spring long-term 

monitoring of the Colorado River.

Rare nonnatives captured in the spring sampling included brown trout (n=17 fish captured), 

common carp (n=4), fathead minnow (n=5), yellow bullhead (n=4), green sunfish (n=1), red 

shiner (n=1), and striped bass (n=1). During autumn monitoring we captured four crayfish and 

one fathead minnow. 

An additional question of interest in recent years has been “Is Pearce Ferry Rapid an 

impediment to fish movement?” Catch data suggest that this rapid became much larger and 

changed hydraulically in approximately 2008 and continues to be dynamic. It may limit 

movement of nonnative fish (e.g., common carp, channel catfish) between Lake Mead and the 

Colorado River in Grand Canyon but could also impede native fish movement. To investigate 

this question, AZGFD installed Passive Integrated Transponder (PIT) tag antennas at the rapid 

and samples fish both upstream and downstream of the rapid (work at rapid and downstream 

of rapid is not funded by GCDAMP). On our Grand Canyon trips, we tagged all flannelmouth 

sucker > 150 mm TL caught downstream of RM 270 to have more tagged fish near the Pearce 

Ferry Rapid PIT antenna array and gain a better understanding of how this rapid affects fish 

movement. Preliminary data, based on the differences in fish assemblage upstream and 

downstream of the rapid, and PIT tag antenna data suggest that the rapid is a hindrance to fish 

movement upstream. 
97

Element I.2. Improve Early Detection of Warm-Water Invasive Fish

Science Questions 

• What warm-water nonnative fish are present in the CRe and how can we improve our

ability to detect new invasions of warm-water nonnative fish before they become

established? 

• Can new eDNA tools be used to effectively collect this information? 

Results

AZGFD conducted spring (March 17-18) and summer (July 14-15) targeted monitoring of 

invasive warm-water species in Glen Canyon in areas where rare nonnatives have been caught 

before. These areas include right up next to the dam, and in warmer water areas such as spring 

inflows, sloughs, and backwaters. In the fall of 2022, these efforts captured 75 bluegills

(Lepomis macrochirus), 15 green sunfish, two green sunfish/bluegill hybrids, 2 common carp, 

and 11 smallmouth bass. The largest smallmouth bass captured was 205 mm TL; all the rest 

were YOY and less than 116 mm TL. Smallmouth bass were also captured in eight of the 40 

standardized monitoring sites along with black crappies (Pomoxis nigromaculatus; 90, 91, 99 

mm TL), which were also captured at standardized monitoring sites (-12.55L, -7.93R, -5.07L, 

respectively). More smallmouth bass were caught in normal standardized monitoring (14) than 

in focused sampling (11), indicating that AZGFD standardized monitoring is sufficient to detect 

this species at current abundances within Glen Canyon.

Two environmental DNA sampling trips were conducted in 2022, with one occurring upstream 

from Lees Ferry on July 15 and one occurring downstream of Lees Ferry from June 1-9 (See FY 

2021-23 work plan for detailed sampling methods). High turbidity during much of the trip made 

filtering water very time consuming. Samples have all been sent to the USDA Forest Service 

Rocky Mountain Research Station for processing and analysis. 

Element I.3. Assess the Risks Warm-Water Nonnative Fish Pose to Native Fish

Science Question

• What are the current impacts of the existing population of introduced channel catfish 

on juvenile humpback chub in the Little Colorado River and are those impacts more or

less of a threat than predation by other introduced fish? 

Results

In 2022, field efforts continued to focus on marking channel catfish within the Little Colorado 

River. We completed five angling trips within the lower 13 km of the Little Colorado River (May 

- June). Only 22 channel catfish were caught and tagged with Passive Integrated Transponder 

(PIT) tags in 171 hours of angling effort (0.13 fish/hour). This represents a four-fold decline in 

catch rates compared to the previous two years of effort. Channel catfish were widely 

distributed throughout the lower 13 km of the Little Colorado River and typically aggregated in 

deeper pools with large boulders. This year the population was dominated by large adult, male 

catfish with the average size being 516 mm TL (range = 335-710 mm Total Length [TL], Figure 2). 
98

Although rarely caught with other sampling methods, adult channel catfish are very susceptible 

to angling with earthworms. Only 3 catfish which were tagged in previous years were 

recaptured. The lack of females, and the few large males that were caught may indicate that 

smaller female channel catfish exited the Little Colorado River or died between 2021 and 2022. 

Movement information from the three recaptured fish this year indicates they are resident fish 

with most recaptures occurring within the same pool complex. No mark-recapture population 

estimate (Lincoln-Petersen method) was able to be calculated in 2022 because of the low 

number of recaptures and the apparent exit of catfish from the Little Colorado River, which 

violates closure assumptions. Warmer mainstem water temperatures may have resulted in 

channel catfish remaining in or moving into the mainstem Colorado River. Incidence of 

piscivory, based on gastric lavage, continues to be relatively high. In 2021, 14.5% of catfish had 

eaten fish within the 24-hour period prior to being caught. In 2022, 27.3% (6 out of 22 fish) of 

catfish had eaten fish within the 24-hour period prior to being caught. This relatively high 

incidence of piscivory may indicate the potential for large negative impacts on all of the native 

fish through predation.

Figure 2. Length frequency histogram for channel catfish angled from the Little Colorado River in 2021 and 2022 (with similar 

effort) indicating reduced numbers and fewer smaller sized fish are present in the Little Colorado River. Preliminary results, do 

not cite.

In 2022, laboratory evaluations of predation risk were focused on the potential impacts of 

channel catfish on juvenile humpback chub and the risks that common carp pose to survival of 

humpback chub eggs. For channel catfish, laboratory predation trials focused on the effects of 

turbidity on predation vulnerability of native fish. In replicated laboratory trials conducted in 

clear water, flannelmouth and razorback sucker (Xyrauchen texanus) were found to be 50-90% 

more vulnerable to channel catfish predation than humpback chub or bonytail chub (Gila 

elegans). When turbidity was increased (250-500 nephelometric turbidity units, NTU) predation 

vulnerability to channel catfish also increased, and species-specific differences in predation 

vulnerability became less apparent, indicating that periods of high turbidity are likely when 

channel catfish are the most detrimental to native fish within the Little Colorado River. 
99

To evaluate the effects of common carp on humpback chub eggs and larvae, seven additional 

replicate trials were conducted with common carp in larger 1,000-gallon tanks with cobble 

substrates (tank size increased by a factor of 5, compared to trials conducted in 2020). Tank size 

was increased to verify that results obtained in 2020 were not just related to small tank size. 

Two common carp adults were allowed access to newly fertilized humpback chub eggs for a 24-

hr period in these larger tanks. Carp predation on eggs resulted in an average 90% decrease in 

humpback chub eggs that survived to swim-up, compared to control tanks with no carp 

present. This effect size is similar to a 2020 experiment, which showed a 96% decrease in egg 

survival in common carp tanks, and demonstrates that common carp are likely to pose a 

significant risk to the survival of humpback chub eggs through predation in the Little Colorado 

River. Adult common carp were also found to be effective predators on juvenile chub and 

suckers. Additional 24-hr laboratory predation trials were conducted using captive reared 

juvenile bonytail (22-70 mm TL), humpback chub (21-49 mm TL), and razorback sucker (47-98 

mm TL) as prey. Chubs and suckers both experienced unexpectedly high predation mortality, 

with the smallest sizes (fish < 80 mm TL) being most vulnerable with up to 50% predation 

mortality occurring in overnight trials conducted in turbid water (500 NTU, figure 3). These 

results demonstrate that common carp are not just a threat to eggs and larval native fish, but 

also to juveniles. This information gives context about potential management actions designed 

to conserve Colorado River native fish. Additional carp-focused management actions within the 

Little Colorado River may be warranted to conserve imperiled native fish.

Figure 3. Probability that juvenile razorback sucker and humpback chub will survive predation by adult common carp in turbid 

water (500 NTU) in replicate overnight trials conducted in the laboratory. Preliminary results, do not cite. 
100

References

Erős, T., Comte, L., Filipe, A.F., Ruhi, A., Tedesco, P.A., Brose, U., Fortin, M.J., Giam, X., Irving, K., 

Jacquet, C., Larsen, S., Sharma, S., and Olden, J.D., 2020, Effects of nonnative species on the 

stability of riverine fish communities: Ecography, v. 43, no. 8, p. 1156-1166, 

https://doi.org/10.1111/ecog.04985. 

Klymus, K.E., Richter, C.A., Chapman, D.C., and Paukert, C., 2015, Quantification of eDNA 

shedding rates from invasive bighead carp Hypophthalmichthys nobilis and silver carp 

Hypophthalmichthys molitrix: Biological Conservation, v. 183, p. 77-84, 

https://doi.org/10.1016/j.biocon.2014.11.020. 

Marsh, P.C., and Pacey, C.A., 2005, Immiscibility of native and non-native fishes, in Brouder, 

M.J., Springer, C.L., and Leon, C.S., eds., Restoring natural function within a modified 

riverine environment—The lower Colorado River, Albuquerque, N.Mex., July 8-9, 1998 and 

in Restoring native fish to the lower Colorado River—Interactions of native and non-native 

fishes, Las Vegas, Nev., July 13-14, 1999, Proceedings of two symposia: p. 59-63, 

http://www.nativefishlab.net/publications/Symp_Marsh&Pacey.pdf. 

Martinez, P., Wilson, K., Cavalli, P., Crockett, H., Speas, D.W., Trammell, M., Albrecht, B., and 

Ryden, D., 2014, Upper Colorado River Basin nonnative and invasive aquatic species 

prevention and control strategy—final report: Lakewood, Colo., U.S. Fish and Wildlife 

Service Upper Colorado River Endangered Fish Recovery Program, 125 p., 

http://www.coloradoriverrecovery.org/general-information/programelements/nna/BASINWIDENNFSTRATEGYFeb2014.pdf. 

Rogowski, D.L., Osterhoudt, R.J., Mohn, H.E., and Boyer, J.K., 2018, Humpback chub (Gila cypha) 

range expansion in the western Grand Canyon: Western North American Naturalist, v. 78, 

no. 1, article 4, https://scholarsarchive.byu.edu/wnan/vol78/iss1/4. 

Ward, D.L., and Morton-Starner, R., 2015, Effects of water temperature and fish size on 

predation vulnerability of juvenile humpback chub to rainbow trout and brown trout: 

Transactions of the American Fisheries Society, v. 144, no. 6, p. 1184-1191, 

https://doi.org/10.1080/00028487.2015.1077160. 

Ward, D.L., 2007, Removal and quantification of Asian tapeworm from bonytail chub using 

Praziquantel: North American Journal of Aquaculture, v. 69, no. 3, p. 207-210, 

https://doi.org/10.1577/A06-054.1. 
101

Project I Budget

Project I Deliverables: Warm-Water Native and Nonnative Fish Research and 

Monitoring 

Presentations:

Frye, E., and Ward D., 2022, Common carp, uncommon predator—presentation: Desert Fishes 

Council 2022 Annual Meeting, November 16-18, 2022, Saint George, Utah.

Frye, E., and Ward D., 2022, Green sunfish, aquatic gremlins of the southwest—poster 

presentation: Desert Fishes Council 2022 Annual Meeting, November 16-18, 2022, Saint 

George, Utah.

Rogowski, R., 2022, Back to the future, warm-water fish in the Grand Canyon—presentation: 

Desert Fishes Council 2022 Annual Meeting, November 16-18, 2022, Saint George, Utah.

Ward D., and Frye, E., 2022, Oxygen manipulation for fisheries management—presentation: 

Desert Fishes Council 2022 Annual Meeting, November 16-18, 2022, Saint George, Utah.

Burden

12.326%

Budgeted

Amount $233,790 $0 $12,100 $273,110 $0 $38,502 $557,502 

Actual

Spent $272,402 $1,724 $18,141 $273,110 $0 $44,218 $609,595 

(Over)/Under

Budget ($38,612) ($1,724) ($6,041) $0 $0 ($5,716) ($52,093)

FY21 Unspent Funds $0 FY22 Unspent Funds ($52,093)

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

-Overspent Salaries is due to assignment of project staff reassigned back to the project to ensure completion of all project tasks 

outlined in the workplan. 

-Overspent funds in travel and training is due to travel and training completed in FY22 that was rescheduled from FY21.

-Overspent funds in Operating Expenses is for purchases of necessary lab equipment and field supplies.

Project I Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total
102

Project J: Socioeconomic Research in the Colorado River 

Ecosystem

Goals and Objectives

In the GCDAMP TWP FY 2021-23 (U.S. Department of the Interior, 2020), Project J is integrating 

economic information with data from long-term and ongoing physical and biological monitoring 

and research studies led by GCMRC. This integration will lead to the development of tools for 

scenario analysis that improve the ability of the GCDAMP to evaluate and prioritize 

management actions, monitoring, and research. In addition, Project J includes monitoring and 

research efforts to better understand recreational behavior related to the brown trout 

incentivized harvest program and recreational preferences for trip attributes (e.g., flows) that 

allow for inference into how recreational economic values are influenced by GCD operations. 

Project J’s primary goal in the GCDAMP TWP FY 2021-23 is to address the humpback chub (Gila 

cypha), hydropower and energy, and sediment or recreational experience LTEMP FEIS resource 

goals. This goal is accomplished by addressing the LTEMP Record Of Decision (U.S. Department 

of Interior, 2016a; U.S. Department of Interior, 2016b) objective to “determine the appropriate 

experimental framework that allows for a range of programs and actions, including ongoing and 

necessary research, monitoring, studies, and management actions in keeping with the adaptive 

management process.” 

Project Elements

Element J.1. Predictive Models for Adaptive Management 

Science Questions

• What is the optimal combination of flow (e.g., Trout Management Flows, TMFs) and 

non-flow actions that improve and support the long-term stability of downstream 

resources (e.g., humpback chub, sediment) and are also able to maintain or improve the 

value of hydropower generation at GCD? 

Results

• Preliminary results indicate that TMFs are viable (effective and economically efficient) 

rainbow trout control measures to achieve humpback chub abundance goals only when

rainbow trout recruitment in Lees Ferry is high, humpback chub aggregation abundance 

Project Lead Lucas Bair

Principal 

Investigator(s) (PI)

Lucas Bair, USGS, GCMRC

Joshua Abbott, ASU

Erich Mueller, SUU

Email lbair@usgs.gov

Telephone (928) 556-7362
103

is low, and rainbow trout abundance in Marble Canyon and the Juvenile Chub 

Monitoring (JCM) reach is high. This baseline result is based on the estimated economic

cost of TMFs (see Project N) relative to rainbow trout removal cost and the effectiveness

of TMFs specified in the LTMEP EIS (U.S. Department of Interior, 2016b). See the FY

2021 GCMRC Annual Report (U.S. Geological Survey, 2021) for additional details related

to preliminary results.

 

In FY 2022, GCMRC and cooperators began the development of a sediment-hydropower 

predictive model that addresses the sediment, hydropower and energy, and recreational 

experience goals. This model uses a sandbar model developed by Mueller and Grams (2021) 

and a sand transport model developed by Wright and others (2010), the hydropower 

optimization model in Project N, and the ongoing research related to recreational boating in 

Grand Canyon (Neher and others, 2019). The model will assist in the identification of optimal 

monthly release volumes with respect to the sediment and hydropower goals. This is important 

given current low water conditions, where the monthly allocation of volume and timing of highflow events maybe more critical to balance resource tradeoffs. 

This project subcomponent aligns with the August 2022 AMWG directive to evaluate high-flow 

experiments under low-elevations in Lake Powell and subsequent annual low flows. The model 

will allow for the evaluation of the frequency, flow, and duration of HFEs that would be 

effective while also considering other objectives such as hydropower. See the GCDAMP TWP FY

2021-23 for additional detail. 

Element J.2.

Science Questions

• How does brown trout monetary harvest incentives impact the number of angler trips, 

targeting behavior, and retention rates at Lees Ferry? 

Results

• We find evidence that this particular program was unsuccessful at drawing additional 

fishing effort (in daily trips) into the fishery, and had mixed results on the number of

brown trout that anglers caught and retained.

The primary objective of Project Element J.2 is to evaluate how structure of monetary payout

from the incentivized harvest program influences participation, harvest, and retention rates 

within the brown trout fishery at Lees Ferry. Understanding these program outcomes and 

underlying behavioral factors will inform approaches to meet removal objectives. In FY 2022, 

GCRMC and Arizona State University (ASU) collaborators closely coordinated with the NPS on 

incentive design for the program. 

GCMRC and ASU will continue to advise the NPS on incentive structure and program design in 

FY 2023. In cooperation with AZGFD (see Project H), in FY 2022 GCMRC also led approximately 

50 days of angler surveys at Lees Ferry. 
104

These angler surveys provide detailed information related to the brown trout incentivized 

harvest program that is important in the first year of the program to determine participation 

rates under various incentive structures. The angler surveys also allowed GCMRC and ASU 

researchers to obtain name and address information of anglers to utilize in a follow-up mail 

survey. The follow-up mail survey will provide a more in-depth evaluation of the incentive 

structure and angler participation of the brown trout incentive program. GCMRC and ASU 

researchers initiated the required Office of Management and Budget review as part of the 

Paperwork Reduction Act in early calendar year 2022. It is anticipated that the survey will be 

approved in early calendar year 2023 and implemented in the same year. 

Potential Lees Ferry anglers face a certain number of choices per-year in which they can decide 

either to take a Lees Ferry fishing trip or to do something else. Conditional on choosing to take 

the trip, anglers can choose how long to fish, where to fish, and what gear to use—all of which 

impact the number of rainbow or brown trout that they catch on that trip. Finally, the angler 

chooses the percent of rainbow and brown trout caught to retain rather than releasing. The 

product of these three decision variables — trips-taken, catch per trip, and retention rate — is 

the total number of rainbow or brown trout that an angler lands, or harvests, in a year (see 

Figure 1).

Figure 1. The factors over which a program incentive may increase brown trout harvests. 

We use daily, angler-level data on fishing behavior and outcomes from the Arizona Game and 

Fish Department Lees Ferry creel survey (January 2016 - May 2022) to estimate the impact of 

the program on brown trout landings, as well as the three behavioral variables (trips, catch-pertrip, and retention rate) that comprise landings (Figure 1). We use these data to investigate any 

potential program-induced changes in trip counts, catch rates (number of rainbow or brown 

trout caught by an angler on a given day), and retention rates (percent of caught rainbow or 

brown trout that each angler retained). The creel technician also records each angler’s gender, 

age, and home zip codes, the number of fishing trips they have taken to Lees Ferry that year, 

how many hours they spent fishing that day, the type(s) of fishing gear they used (fly, spin, or 

both), and which species (rainbow trout, brown trout, or both) they were targeting. 
105

We use this information, including hours fished and gear use, to help explain how and why 

catch rates changed after the program was implemented. We estimate five separate models in 

order to investigate the direct impact of the program on brown trout harvest, as well as any 

indirect effects of the program on rainbow trout harvest. Our models estimate the program’s 

impact on trip-taking as well as on brown trout and rainbow trout catch-per-trip and retention 

rates amongst unguided boat anglers. Because guided anglers largely do not participate in the 

program, we assume they are untreated and drop their data from our estimations to avoid 

biasing our results. The models control for season, hydrology, weather, and COVID-19 impacts. 

Our preliminary results suggest that the Lees Ferry Incentivized Harvest Program failed to bring 

additional angling effort (i.e., daily trips) into the fishery, likely due to how remote and costly it 

is to access the fishery. Interestingly, the program seems to have had an unambiguously 

negative impact on catch per trip for both rainbow and brown trout. With no increase in trips 

due to the program, this suggests that anglers changed their targeting behavior (i.e., where 

they fished, what gear they used, etc.) in response to the program treatment, but either 

crowded out each other’s efforts or lacked Lees Ferry-specific knowledge on where and how 

best to target brown trout. We plan to further investigate this hypothesis by assessing how 

catch-contributing behaviors (i.e., gear use, hours fished) changed post-treatment to look for 

possible mechanisms to explain this post-treatment drop-in catch rates. We also find mixed 

results on whether or not the program had a positive or negative effect on brown trout 

retention rates. Because retention rates are a fraction, and thus bounded at one, it may be the 

case that these ambiguous results reflect minimal ability for the program to increase retention 

rates in the participating population. We plan to explore this hypothesis further and also assess 

how retention rates may have changed according to angler type to identify potential 

mechanisms driving these results.

Element J.3. Recreation Monitoring and Research

The objective of Project Element J.3 is to further refine our understanding of recreational 

preferences for specific flow attributes as controlled by operations at GCD and within the flow 

parameters of the LTEMP ROD (U.S. Department of Interior, 2016b). No funded research was 

conducted in FY 2022. 

References

Bair, L.S., Rogowski, D.L., Neher, C., 2016, Economic value of angling on the Colorado River at 

Lees Ferry—Using secondary data to estimate the influence of seasonality: North American 

Journal of Fisheries Management, v. 36, no. 6, p. 1229-1239, 

https://doi.org/10.1080/02755947.2016.12043888. 

Bair, L.S., Yackulic, C.B., Springborn, M.R., Reimer, M.N., Bond, C.A., and Coggins, L.G., 2018, 

Identifying cost-effective invasive species control to enhance endangered species 

populations in the Grand Canyon, USA: Biological Conservation, v. 220, p. 12-20, 

https://doi.org/10.1016/j.biocon.2018.01.032. 
106

Donovan, P., Bair, L.S., Yackulic, C.B., and Springborn, M.R., 2019, Safety in numbers—Costeffective endangered species management for viable populations: Land Economics, v. 95, 

no. 3, p. 435-453, https://doi.org/10.3368/le.95.3.435. 

Mueller, E.R., Grams, P.E., 2021, A morphodynamic model to evaluate long-term sandbar 

rebuilding using controlled floods in the Grand Canyon: Geophysical Research Letters, v. 48, 

no. 9, e2021GL093007, https://doi.org/10.1029/2021GL093007. 

Neher, C., Duffield, J., Bair, L., Patterson, D., Neher, K., 2017, Testing the limits of temporal 

stability—Willingness to pay values among grand canyon whitewater boaters across 

decades: Water Resources Research, v. 53, no. 12, p. 10108-10120, 

https://doi.org/10.1002/2017WR020729. 

Neher, C., Bair, L., Duffield, J., Patterson, D., Neher, K., 2019, Convergent validity between 

willingness to pay elicitation methods—An application to Grand Canyon whitewater 

boaters: Journal of Environmental Planning and Management: v. 62, no. 4, p. 611-625, 

https://doi.org/10.1080/09640568.2018.1435411. 

U.S. Department of Interior, 2016a, Record of Decision for the Glen Canyon Dam Long-Term 

Experimental and Management Plan final Environmental Impact Statement (LTEMP ROD): 

Salt Lake City, Utah, U.S. Department of the Interior, Bureau of Reclamation, Upper 

Colorado Region, National Park Service, Intermountain Region, 22 p. plus appendices, 

http://ltempeis.anl.gov/documents/docs/LTEMP_ROD.pdf. 

U.S. Department of Interior, 2016b, Glen Canyon Dam Long-term Experimental and 

Management Plan final Environmental Impact Statement (LTEMP FEIS): U.S. Department of 

the Interior, Bureau of Reclamation, Upper Colorado Region, National Park Service, 

Intermountain Region, online, http://ltempeis.anl.gov/documents/final-eis/. 

U.S. Department of the Interior, 2020, Glen Canyon Dam Adaptive Management Program 

Triennial Budget and Work Plan—Fiscal years 2021-2023—Final approved by the Secretary 

of the Interior—December 2, 2020: Flagstaff, Ariz., U.S. Geological Survey, Grand Canyon 

Monitoring and Research Center, and Salt Lake City, Utah, Bureau of Reclamation, Upper 

Colorado Region, 384 p., 

http://gcdamp.com/images_gcdamp_com/5/5d/GCMRC_TWP2021-

23_December2_2020_ApprovedBySecretary.pdf. 

U.S. Geological Survey Grand Canyon Monitoring and Research Center, 2021, Fiscal Year 2021 

Annual Project Report to the Glen Canyon Dam Adaptive Management Program: Flagstaff, 

Ariz., prepared by the U.S. Geological Survey, Southwest Biological Science Center, Grand 

Canyon Monitoring and Research Center, December 16, 2021, 251 p.

Wright, S.A., Topping, D.J., Rubin, D.M., Melis, T.S., 2010, An approach for modeling sediment 

budgets in supply-limited rivers: Water Resources Research, v. 46, no. 10, 

https://doi.org/10.1029/2009WR008600. 
107

Project J Budget

Project J Deliverables: Socioeconomic Research in the Colorado River Ecosystem

Presentations:

Bair, L.S., and Bain, D.M., 2021, Identifying the total economic value of hydropower and 

implications for adaptive management of rivers—Operating restrictions of hydroelectric 

plants and their impacts on the operation of the Brazilian electric system—virtual 

presentation: XXIV Brazilian Symposium on Water Resources, November 2022.

Bair, L.S., 2021, Adaptive management and cultural ecosystem services—virtual presentation:

ACES: A Community on Ecosystem Services conference, December 2022.

Bair, L.S. and Neher, C., 2022, Recreational anglers’ preferences for flow attributes—Taking 

advantage of a designer flow to validate novel scenarios—virtual presentation: The 

International Institute of Fisheries Economics and Trade, July 18-22, Vigo, Spain.

Bair, L.S., 2022, Consideration of plural values in integrated assessments—presentation: AGU 

Chapman Conference on Solving Water Availability Challenges through an Interdisciplinary 

Framework, September 12-16, Golden, Colorado. 

Journal Articles:

Donovan, P., Reimer, M.N., Springborn, M.R., Yackulic, C.B., Bain, D.M., Bair. L.S., in prep, The 

economic cost of designer flows in river conservation.

Hoelting, K., Morse, J.M., Gould, R., Martinez, D.E., Hauptfeld, R.S., Cravens, A.E., Breslow, S., 

Bair, L.S., Schuster, R.M., and Gavin, M.C., 2022, Opportunities for improved consideration 

of cultural benefits in environmental decision-making: SocArXiv, p. 1-42, 

https://doi.org/10.31235/osf.io/dpbe3. 

Jungers, B., Abbott, J.K., Bair, L.S., in prep, Program evaluation of the Lees Ferry brown trout 

incentivized harvest program. 

Burden

12.326%

Budgeted

Amount $124,588 $3,000 $1,500 $45,500 $0 $17,276 $191,864 

Actual

Spent $95,952 $5,874 $9,782 $69,000 $0 $15,827 $196,435 

(Over)/Under

Budget $28,636 ($2,874) ($8,282) ($23,500) $0 $1,449 ($4,571)

FY21 Unspent Funds $0 FY22 Unspent Funds ($4,571)

To other

USGS Centers Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

- Underspent Salaries is due to change in mechanism for completing work with cooperators and contractors instead of salaried 

employees. 

- Overspent Travel & Training is due to an international workshop organized by The Amazon Dams Network in Brazil.

- Overspent funds in Cooperative Agreement is due to change in mechanism for completing work with cooperators and 

contractors.

Project J Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements
108

Project K: Geospatial Science and Technology

Goals and Objectives

The Geospatial Science and Technology project (Project K) provides support to USGS Grand 

Canyon Monitoring and Research Center (GCMRC) science projects in the areas of Geographic 

Information Systems (GIS) expertise, database development and operation, programming and 

source control for code development, web application development, and other tasks for 

producing online data resources. The scope of support provided by this project now 

encompasses application of enterprise-scale relational databases, use of standard source 

control platforms for managing programming code and software/application development, 

migration of project data away from flat files and into enterprise database systems, and 

providing consultation for projects on possible migration of data resources into the USGS’ Cloud 

Hosting Solutions (CHS) environment within Amazon Web Services (AWS) cloud platform, or 

other suitable endpoints. 

Most work performed within Project K falls within one of three main categories, presented as 

Project Elements in the FY 2021-2023 Triennial Work Plan (TWP) —Geospatial Data Analysis, 

Geospatial Data Management, and Access to Geospatial Data Holdings and Online Data 

Resources. Many aspects of the efforts put forth through this project often overlap from one 

element to another and can be discussed in all three of these elements. The approach Project K 

has employed for these project elements has had two underlying threads – 1) support the 

overall GCMRC needs through the development of systems and resources, building capacity and 

expertise along the way, and 2) support science projects with specific tasks that align with 

modernizing and improving upon each project’s data management, analysis, and data access 

strategies, usually by leveraging newer technologies to achieve these goals.

Project Elements

Element K.1. Geospatial Data Analysis: Support to Science Projects 

GIS Administration

Work performed for Project Element K.1 is designed to support research and monitoring 

projects from the FY 2021-2023 TWP by providing geospatial expertise to most projects on field 
109

mapping methods, development of customized maps, sample site unit definition and selection, 

GIS layer development, and GIS tool development and support. 

Often this work involved the oversight and supervision of science project staff with various GISrelated tasks including spatial analysis in support of projects, training for staff and cooperators 

in GIS data entry and database management concepts, data processing techniques, production 

of printed maps and online map products, error troubleshooting, and other basic GIS methods 

and techniques. GIS Administration tasks related to GCMRC-wide support included the testing 

and migration of systems to newer versions of the most commonly used GIS/Remote Sensing 

software, maintaining licensing information and working with SBSC IT staff to ensure all 

licenses, software, extensions, add-ons, and custom applications work properly. 

This work includes the installation, configuration, and administration of ESRI Desktop ArcGIS 

and Enterprise GIS software for GCMRC (ESRI, 2020). Additionally, this project is responsible for 

handling data calls pertaining to a wide array of GCMRC’s data resources every year. In FY 2022, 

Project K expanded on its use of the open-source PostgreSQL relational database platform for 

storing, maintaining, and serving GCMRC’s enterprise geospatial data sets. Data sets currently 

hosted include past and recent remote sensing overflight imagery, topography and bathymetry 

of the Colorado River corridor, commonly used canyon-wide locational and thematic data sets, 

and project-specific geospatial data. Additional relational database work is also addressed 

under Project Element K.2.

Advances in Data Science Support

Project K has continued to lead GCMRC in the use of Tableau data visualization for developing 

compelling views of some of GCMRC’s most critical data assets. In the background, Project K 

continues to manage the licenses for this software in coordination with the USGS’ Cloud 

Hosting Solutions team and has expanded on the capacity needed for creating compelling, 

database-driven analytical capabilities through additional licenses for staff. Additional 

accomplishments this year included building proficiencies in connecting different data sources 

in Tableau, filtering data down to appropriate levels, and developing novel techniques for 

linking cloud-based databases to Tableau Server and publishing those data sources. Much work 

still remains to expand the use of this software to support other science projects and improve 

upon ways that managers and stakeholders within the GCDAMP can access scientific data. 

More on the online availability of Tableau data visualizations is discussed in Project Element 

K.3.

Element K.2. Geospatial Data Management, Processing, and Documentation 

Geospatial data management tasks included making updates to server hardware and software, 

updating existing applications to comply with new security measures, and testing and 

troubleshooting connectivity to internal systems – such as existing relational databases 

(PostgreSQL, Microsoft SQL Server) – as well as external clients that range from desktop 

applications (ArcGIS ArcMap and Pro, QGIS) to web-based endpoints (REST services, online 

applications, ArcGIS Online content, see Project Element K.3. and Products sections). 
110

Work performed within this project also includes collaboration, coordination, and occasionally 

oversight of SBSC Information Technology staff and initiatives as they relate to GCMRC science. 

This oversight and coordination has benefitted GCMRC by ensuring that proper IT infrastructure 

and computing resources are made available to GCMRC science staff. 

Enterprise Database Management

Project K staff continued to lead the GCMRC in the maintenance and further development of 

open-source databases, specifically building upon the work in fiscal year 2021 to migrate to the 

PostgreSQL relational database management system (RDBMS). We have expanded the 

collection of databases now hosted in our Linux-based Postgres environment to seven database 

endpoints, each uniquely configured to optimize storage and retrieval of either tabular-centric 

or geospatial-centric data resources for GCMRC. Most notably is GCMRC’s Fish Monitoring 

Database, which has received a great deal of attention toward improving both how the 

database functions to the workflows employed to import field collected data to how the data 

are accessed for reporting and analysis. This effort began with improving the communication 

between Project K staff and fish biologists who are the data stewards of this information. 

Through improved coordination efforts to communicate new processes and workflows, Project 

K has greatly improved on the entire approach for data entry, quality assurance and quality 

control (QA/QC) procedures, and reporting out on the status of the fish monitoring database. 

We now can now view, in real-time, the Fish Monitoring Database trip status through a widely 

available data visualization (Figure 1) that shows the Month, Trip ID, Total Samples per trip, and 

Total Specimens per trip. This is a draft visualization shared with all fish cooperators via a 

dedicated Microsoft Teams channel for fish monitoring. Future plans include making this and 

similar data visualizations available to the larger GCDAMP community.

Also in FY 2022, a large amount of effort was put toward finalizing the Lake Powell WaterQuality database. This effort involved close coordination with the Lake Powell water-quality 

principal investigator (Deemer) and a significant amount of time to fix issues with the data 

entry of certain water-quality parameters and refine the QA/QC process for sampling data. This 

work has led to a data release and a peer-reviewed journal article on the Lake Powell WaterQuality database and established workflows that are now being used (Deemer and others, 

2023). 
111

Figure 1. View of Tableau data visualization of fish monitoring database showing the trip data entry status along with number of 

total samples and total specimens by species collected for each trip.

Management of Cloud Environment Usage for Science Project Support

Project K has led GCMRC in expanding the role of data management to include a hybird-cloud 

approach for future data needs and, more specifically, project staff actively maintain GCMRC’s 

resources in the Amazon Web Services (AWS) cloud environment. This work continues to 

require coordination at a high-level with GIS and IT staff at the USGS Southwest Biological 

Science Center (SBSC), USGS CHS team members across the country, USGS project leads from 

other science centers, and contractual partners from the private sector. There were several 

goals outlined for this past year, with the most notable as follows:

1. Further develop the GCMRC’s capacity for working in and building applications in

AWS. 

2. Coordinate with SBSC IT staff to analyze and refine both on-premises data 

management operations and utilization of cloud storage and computing resources to 

better support science projects. 
112

3. Build more proficiency among science project staff and Project K staff to work with 

relational databases and online data services, and develop new or novel data 

visualizations that leverage newer technologies and highlights GCMRC science.

Expanding Use of Source Control

Project K has continued to the lead GCMRC in developing and managing geoprocessing scripts, 

web applications, and other work involving programming through online source control and 

versioning platforms. Leveraging these source control platforms has led to greater efficiency in 

code development and faster development of new web applications than previously possible. It 

also has led to greater collaboration between code development for different GCMRC science 

projects. By continuing to promote and use source control for GCMRC, the Geospatial team can 

better serve in an advisory role for GCMRC scientists and technical staff and allow for greater 

collaboration with cooperators and other external entities.

Element K.3. Access to Geospatial Data and Online Data Resources 

Project Element K.3 often is the culmination of efforts described in the previous two elements. 

Without having properly identified data need requirements for other GCMRC science projects 

and then having those data properly managed, often through the use of enterprise relational 

database management systems, being able to serve GCMRC’s data resources online becomes 

more difficult. Project Elements K.1. and K.2. are building blocks for improving the access to 

GCMRC’s data resources, including through online applications. Described here are three 

components of this element: 1) continued maintenance and improvements to GCMRC’s online 

geospatial data, 2) an increase in the use of online data visualizations to support science 

projects, and 3) the continued emergence of GCMRC’s Internet of Things (IoT) data telemetry 

efforts. 

Project K continued to perform all the administration, installation, system upgrades, and 

content expansion made available through an online portal (Grand Canyon Geospatial Portal, 

https://grandcanyon.usgs.gov/portal/home/) as well as sharing many of these data services 

through the ESRI ArcGIS Online (https://www.arcgis.com/) cloud platform. This work also 

involved configuring, testing, and publishing new geospatial data sets to the Grand Canyon 

Geospatial Portal that directly support GCMRC science projects. Often, administration tasks 

required close coordination with other USGS IT entities to resolve web-based application and 

other online content issues, as well as working to improve performance in delivering GCMRC 

geospatial content online. 

Internet of Things (IoT) Sensor-to-Cloud Data Transmission

We have expanded GCMRC’s use of the USGS’ Cloud Hosting Solutions (CHS) Sensor Processing 

Framework and provided unparalleled opportunities for accessing important GCMRC data 

resources. In FY 2022, Project K work focused on improving the stability of the existing IoT study 

sites. This work involved a considerable amount of re-engineering both physically and in system 

configurations and programming code used to perform the data telemetry tasks at our 

established sites. 
113

Additionally, this work involved site visits for performing maintenance of our IoT systems; 

however, with the improvements added over the past year, it is expected that the number of 

site visits and the amount of system downtime will be greatly reduced. It is important to 

underline that GCMRC’s telemetry sites are not any different than the more traditional field 

data collection in that these systems have been established and are operating in very remote 

locations, characterized by extreme conditions and terrain – these characteristics add 

challenges to performing this type of work.

Figure 2. Slide from a presentation given on the advances made in GCMRC’s data telemetry using modern Internet of Things 

technologies. The schematic illustrates the technological stack employed and the workflow used to make the data available 

online in near real-time. 

Continued coordination led by Project K has allowed GCMRC to leverage USGS resources, 

including continued involvement with Cloud Hosting Solutions and the CHS Sensor Cloud 

Processing Framework, the Center for Data Integration, and the Actionable and Strategic 

Integrated Science and Technology (ASIST) project. The ASIST project is the next generation of 

the previous Earth Monitoring, Analysis, and Prediction (EarthMAP) initiative and associated 

Colorado River Basin pilot project that was instituted to improve data workflows, modeling, and 

prediction for the Colorado River Basin. In FY 2022, Project K staff presented on the efforts to 

modernize data collection along the Colorado River as a part of the ASIST session at the 

Colorado Plateau Biennial Conference (Figure 2). The list of data telemetry sites includes waterquality monitoring at Glen Canyon Dam and the Lees Ferry gaging station, suspended-sediment 

monitoring at five locations along the Colorado River, and fish antenna array pit-tag data from 

the Little Colorado River. 
114

For the water-quality IoT sites, data sent to the AWS cloud via cellular signal are used as the 

source for displaying certain water-quality parameters in near real-time using the Tableau 

Server software and online data visualization application (Figure 3). 

By leveraging the power of cloud computing, we are able to view and share these important 

data almost instantaneously, improving on a process that would take from days to weeks to do 

previously. Now, GCMRC researchers and other DOI entities are able to view these data 

through a series of dashboard tools, share the data visualizations with other researchers and 

stakeholders, and download the data for further consumption. 

Figure 3. Viewing of online data visualization of Glen Canyon Dam water-quality information.These data have been published as 

a versioned data release (Andrews and Deemer, 2022) and available to GCMRC and the Bureau of Reclamation since 2022. 

The data visualization will be made publicly available in 2023. Preliminary, do not cite.

References

Andrews, C.M., and Deemer, B.R., 2022, Limnology data from Lake Powell, desert southwest 

USA: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZIKVYW. 

Deemer, B.R., Andrews, C.M., Strock, K.E., Voichick, N., Hensleigh, J., Beaver, J.R., and Radtke, 

R., 2023, Over half a century record of limnology data from Lake Powell, desert southwest 

United States: From reservoir filling to present day (1964–2021): Limnology and 

Oceanography Letters, online, https://doi.org/10.1002/lol2.10310. 

ESRI, 2020, ArcGIS Enterprise software—copyright 1995–2020: Redlands, Calif., Environmental 

Systems Research Institute, accessed May 14, 2020, https://www.esri.com/en-us/legal/copyrighttrademarks/. 
115

Project K Budget

Project K Deliverables: Geospatial Science and Technology

Note: listed here are products that include Project K staff as authors; however, the work plan 

and budget for some products reside in other science projects.

Presentations:

Gushue, T.M., Andrews, C.M., and Thomas, J.E., 2022, Modernizing sensor data workflows to 

leverage Internet of Things (IoT) and cloud-based technologies—presentation: USGS 

Community for Data Integration monthly meeting, May 2022.

Gushue, T.M., Thomas, J.E., 2022, Modernizing sensor data workflows to leverage Internet of 

Things (IoT) and cloud-based technologies—presentation: USGS Cloud Hosting Solutions 

customer user group meeting, August 2022.

Gushue, T.M., Thomas, J.E., and Andrews, C.M., 2022, Modernizing data telemetry efforts for 

important riparian resources in the Grand Canyon—abstract for 16th Biennial Conference 

for Science and Management on the Colorado Plateau and Southwest Region, September 

12-15, 2022: Flagstaff, Ariz., U.S. Geological Survey, Southwest Biological Science Center, 

Grand Canyon Monitoring and Research Center, Flagstaff, Ariz. 

Thomas, J.E., Gushue, T.M., Andrews, C.M., and Unema, J., 2022, Using NWIS data from 

multiple gauging stations to capture event based video—presentation: USGS Community for 

Data Integration 2023 Request for Proposals Lightning Presentations.

Journal Articles:

Deemer, B.R., Andrews, C.M., Strock, K.E., Voichick, N., Hensleigh, J., Beaver, J.R., and Radtke, 

R., 2023, Over half a century record of limnology data from Lake Powell, desert southwest 

United States: From reservoir filling to present day (1964–2021): Limnology and 

Oceanography Letters, online, https://doi.org/10.1002/lol2.10310. 

Burden

12.326%

Budgeted

Amount $372,175 $4,970 $3,400 $0 $0 $46,906 $427,451 

Actual

Spent $275,035 $0 $11,342 $0 $0 $35,299 $321,676 

(Over)/Under

Budget $97,140 $4,970 ($7,942) $0 $0 $11,607 $105,775 

FY21 Unspent Funds $0 FY22 Unspent Funds $105,775

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

- Unspent Salaries is due to staff turnover in FY22 and HR-delays in hiring of a Database Administrator and a Geographer which 

will occur in FY23. 

- Unspent Travel & Training money due to travel restrictions imposed by COVID-19 pandemic.

-Overspent funds in Operating Expenses is for purchases of necessary information technology hardware and equipment for 

remote data collection and transmission.

Project K Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total
116

USGS Reports:

Kaplinski, M., Hazel, J.E., Jr., Grams, P.E., Gushue, T.M., Buscombe, D., and Kohl, K., 2022, 

Channel mapping of the Colorado River from Glen Canyon Dam to Lees Ferry in Glen Canyon 

National Recreation Area, Arizona: U.S. Geological Survey Open-File Report 2022-1057, 20 

p., https://doi.org/10.3133/ofr20221057. 

USGS Data Releases:

Andrews, C.M., and Deemer, B.R., 2022, Limnology data from Lake Powell, desert southwest 

USA: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZIKVYW. 

Kaplinski, M., Hazel, J.E. Jr, Grams, P.E., Gushue, T.M., Buscombe, D.D., and Kohl, K., 2022, 

Channel mapping Glen Canyon Dam to Lees Ferry in Glen Canyon National Recreation Area, 

Arizona - Data: U.S. Geological Survey data release, https://doi.org/10.5066/P98GFP93. 

Manuals:

Thomas, J.E., 2022, Little Colorado River humpback chub Pit Tag master controller IoT system—

User and maintenance manual: Flagstaff, Ariz., U.S. Geological Survey, Southwest Biological

Science Center, Grand Canyon Monitoring and Research Center, SBSC-GCMRC-IoT Gitlab 

repository, https://code.usgs.gov/sbsc/sbsc-gcmrc-iot/little-colorado-river-mux-antenna/-

/blob/main/Little_Colorado_River_Pit_Tag_Master_Controller_Manual_V1.pdf. 

Thomas, J.E., 2022, Satellite remote relay design—User and maintenance manual, Flagstaff, 

Ariz., U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon

Monitoring and Research Center, SBSC-GCMRC-IoT Gitlab repository, 

https://code.usgs.gov/sbsc/sbsc-gcmrc-iot/iot-utilities/-

/blob/main/Satellite%20Relay%20System/Satellite_Remote_Reboot_Manual_V1.pdf. 

Thomas, J.E., 2022, Taylor Woods IoT Datalogger—User and maintenance manual: Flagstaff, 

Ariz., U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon

Monitoring and Research Center, SBSC-GCMRC-IoT Gitlab repository, 

https://code.usgs.gov/sbsc/sbsc-gcmrc-iot/taylor-woods-iot-data-loggers/-

/blob/main/Taylor_Woods_IoT_Datalogger_Manual_V2.pdf. 

Websites & Web Applications:

• Updated Sandbar Monitoring Data website: https://www.usgs.gov/apps/sandbar/

• Sandbar Monitoring Photo Viewer: 

https://grandcanyon.usgs.gov/gisapps/sandbarphotoviewer/RemoteCameraTimeSeries.

html

• Adopt-A-Beach Sites Photo Viewer: https://grandcanyon.usgs.gov/gisapps/adopt-abeach/index.html

• Grand Canyon Geospatial Portal: 

https://grandcanyon.usgs.gov/portal/home/index.html

• Geospatial Services page (for advanced GIS users and developers):

https://grandcanyon.usgs.gov/gisapps/restservices/index_wret.html
117

Web Content on ESRI ArcGIS Online: 

• Predicted Shorelines for High Flows on the Colorado River Application:

https://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=721001c63d9145888

3340f05c68c55f4 

• River Campsite Web Application: 

https://usgs.maps.arcgis.com/home/item.html?id=0f9f6575bfee406cac6593b29388366

5

• Access to Geospatial Data Holdings – ESRI’s ArcGIS Online (note: some content not

shared to the public): 

http://usgs.maps.arcgis.com/home/search.html?q=GCMRC&t=content

Online Data Visualizations: 

Gushue, T.M, and Thomas, J.E., 2021, Daily Water-Quality Data at Glen Canyon Dam—online 

data visualization: Flagstaff, Ariz., U.S. Geological Survey, Southwest Biological Science

Center, Grand Canyon Monitoring and Research Center,

https://tableau.usgs.gov/t/InternalGuestAccess/views/WaterQualityatGlenCanyonDam/Dail

yWaterQualityDataatGlenCanyonDam?%3Aembed=y&%3AisGuestRedirectFromVizportal=y

#1. 

Hensleigh, J., Andrews, C.M., Voichick, N., and Deemer, B., 2022, Lake Powell vertical waterquality profiles—online data visualization: Flagstaff, Ariz., U.S. Geological Survey, Southwest 

Biological Science Center, Grand Canyon Monitoring and Research Center,

https://tableau.usgs.gov/views/view-profiles-by-station-collectiondate/ProfileByStationVisitDateDashboard.
118

Project L: Remote Sensing Overflight in Support of Long-Term 

Monitoring and LTEMP

Goals and Objectives

This project seeks to acquire high-resolution multispectral imagery, a digital elevation model 

(DEM), and a Digital Surface Model (DSM) of the Colorado River and riparian area from the 

forebay of Glen Canyon Dam downstream to Lake Mead, and along the major tributaries to the 

Colorado River. The data collection mission occurred in 2021. During 2022 the data were 

processed in order to prepare them for publication in 2023. 

The data sets derived from remote sensing overflights have proven to be extremely valuable to 

all the research projects conducted by GCMRC over the past two decades. Importantly, 

scientific research which relied heavily on these data were the basis for the 2016 Long-term 

Experimental and Management Plan (LTEMP) (U.S. Department of Interior, 2016a). Given that 

the last overflight was conducted in 2013, and given the physical, geographic and logistical 

constraints of the Colorado River in Grand Canyon, system-wide remotely-sensed data were 

deemed necessary in 2021 to complement ground-based data collection and assist with the 

GCMRC’s efforts to effectively assess these impacts for the entire river ecosystem over decadal 

time frames. The imagery and derivative data products from overflight remote sensing are used 

either directly or indirectly by every science project reporting herein to address every resource 

goal of the LTEMP.

While this work is discussed within the context of FY 2022 of the FY 2021-2023 Triennial Work 

Plan (TWP), the nature and justifications for conducting the overflight are directed at the 

GCMRC’s ability to respond to and deliver information for the LTEMP implementation process 

that tracks decadal-scale changes to resources system-wide. As such, the overflight is a 

scientific effort that has both an immediate and a longer-term payoff; future LTEMP studies will 

require similar information that can be effectively derived from remotely-sensed data acquired 

over coming decades. For these reasons, this project is mission critical to successfully inform 

the GCDAMP on performance of the LTEMP ROD (U.S. Department of Interior, 2016b).

Project Lead Joel Sankey

Principal 

Investigator(s) (PI)

Joel Sankey, USGS, GCMRC

Thomas Gushue, USGS, GCMRC

Keith Kohl, USGS, GCMRC

Email jsankey@usgs.gov

Telephone (928) 556-7289
119

Project Elements

Element L.1.

Science Questions/Hypotheses Addressed

Science Question 1

• How has landcover changed in the Colorado River Ecosystem (CRe) in 2021 relative to 

preceding decades?

Science Question 2 

• How are observed landcover changes related to dam operations, other land use, and 

management activities, as well as climate and other environmental factors in the 

ecosystem?

Results

To address the defined Science Questions for Project L the FY 2022 focus was to (Table 1): 1) 

conduct QA/QC of the data sets acquired by the contractor Fugro Geospatial, Inc. (Fugro) during 

the 2021 overflight, 2) implement final modifications to data, and 3) begin the USGS publication 

process for finalized data sets of the high-resolution multispectral image orthomosaic and a 

digital surface model for the Colorado River riparian ecosystem from Glen Canyon Dam to Lake 

Mead. 

Fugro delivered draft image mosaic and DSM data sets to GCMRC during the first quarter (Q1) 

of FY 2022. GCMRC reviewed those data, requested revisions, and then during Q2 worked in 

coordination with the contractor to review and request further revisions to the data sets. In Q3, 

the contractor delivered the final revised data sets and GCMRC accepted the data sets and 

closed the contract with Fugro for the 2021 overflight data acquisition and delivery.

The contractor was responsible for initial data processing including mosaicking of a DSM (digital 

surface model) and interpolation to develop a DEM (digital elevation model), as well as creating 

orthorectified images of the individual flightlines to build a complete image orthomosaic for the 

collection area. The processes of developing the image mosaic, and of developing a DEM from 

the DSM were new contractor deliverables for the 2021 image collection; in 2009 and 2013, for 

example, GCMRC scientists were responsible for creating this data product. Including the 

mosaic and DEM as deliverables in the contract was intended to reduce project costs and make 

it possible for GCMRC scientists to work on derivative data products and related science more 

quickly after the overflight than from previous missions. 

Data sets Delivered by Contractor 

• DEM (digital elevation model) and DSM (digital surface model); 1-meter pixel resolution

• L2 (orthos): individual flightlines collected from the airborne sensor. This includes all

Nadir look lines as well as supplemental Backward and Forward look strips to 

compensate for “Hot-Spots” and “Glint” present in Nadir channels.
120

• Ortho Mosaic: Complete mosaic using error free flightlines; 20cm pixel resolution with

four bands (Blue, Green, Red, Near-infrared). These data are sectioned based on USGS

7.5 quadrangle maps.

The project focus for FY 2022 was to conduct the quality assurance and quality control (QA/QC) 

at GCMRC. GCMRC reviewed each iteration of draft data sets for completion and requested 

edits to assure they meet the standards defined in the contract. We will extensively review the 

mosaic as this is a new deliverable from the contractor. When the project was initially 

developed, GCMRC project staff anticipated they would need to conduct image processing 

steps to fix issues associated with shadowing and topographic distortion in discrete locations 

throughout the data sets to prepare them for publication as USGS data sets. Project staff are 

currently working on this phase of the project, using flightlines from the L2 (orthos) deliverable, 

to modify the mosaic and remove errors as necessary to prepare the data for publication. We 

also withheld ground control locations to complete an internal accuracy assessment of the 

registration of the image data and the vertical accuracy of the DSM and DEM data sets. 

At the time of writing this report, the DSM and DEM data are in review for publication, and 

progress on the image mosaic data set is on track and those data are expected to be published 

in 2023 as planned. In 2023, final checks will be to compare the mosaic to past mosaic data sets 

(years 2002, 2009, 2013) to make sure that the data are acceptable to evaluating decadal 

trends in the Colorado River ecosystem. Once the checks for QA/QC and accuracy are 

completed GCRMC, scientists will begin working on derivative data products. These include 

water, sand, and vegetation maps.
121

Table 2. Timeline of major activities and work effort for the overflight mission and remote sensing data 

analysis in Project L during the FY 2021-23 Triennial Work Plan.

Fiscal 

Year Quarter(s) Activities

2021

1st

Write Task Order and negotiate contract with GPSC 

(USGS Geospatial Products and Services Contracts) 

and contractor for overflight mission consisting of 

imagery and digital topographic data acquisition

2nd

Contract awarded to Fugro Geospatial Earth Data

Coordinate logistics for the overflight mission with 

GCDAMP agencies and stakeholders.

Plan GCMRC logistics, including the rim- and riverlevel operations to be conducted by GCMRC in 

coordination with the contractor.

3rd

Overflight mission

Rim-level GPS base station operations

River-level accuracy assessment and groundtruthing operations.

4th Monitor image processing performed by Fugro 

(contractor)

2022

1st

Data delivered to GCMRC

QA/QC performed by GCMRC in coordination with 

vendor

2nd Final modifications to mosaic performed by GCMRC

3rd & 4th Begin publication process at GCMRC for finalized 

mosaic

2023 All

Image mosaic published by GCMRC

Landcover classification maps produced by GCMRC 

remote sensing staff 
122

Project L Budget

References

U.S. Department of Interior, 2016a, Glen Canyon Dam Long-Term Experimental and 

Management Plan final Environmental Impact Statement (LTEMP FEIS): U.S. Department of 

the Interior, Bureau of Reclamation, Upper Colorado Region, National Park Service, 

Intermountain Region, online, http://ltempeis.anl.gov/documents/final-eis/. 

U.S. Department of Interior, 2016b, Record of Decision for the Glen Canyon Dam Long-Term 

Experimental and Management Plan final Environmental Impact Statement (LTEMP ROD): 

Salt Lake City, Utah, U.S. Department of the Interior, Bureau of Reclamation, Upper 

Colorado Region, National Park Service, Intermountain Region, 196 p., 

http://ltempeis.anl.gov/documents/docs/LTEMP_ROD.pdf. 

VanderKooi, S.P., Kennedy, T.A., Topping, D.J., Grams, P.E., Ward, D.L., Fairley, H.C., Bair, L.S., 

Sankey, J.B., Yackulic, C.B., and Schmidt, J.C., 2017, Scientific monitoring plan in support of 

the selected alternative of the Glen Canyon Dam Long-Term Experimental and Management 

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

Geological Survey Open-File Report 2017-1006, 18 p., 

https://doi.org/10.3133/ofr20171006. 

Burden

12.326%

Budgeted

Amount $164,641 $0 $0 $80,596 $0 $22,712 $267,949 

Actual

Spent $153,144 $2,286 $11,482 $80,596 $0 $22,992 $270,501 

(Over)/Under

Budget $11,497 ($2,286) ($11,482) $0 $0 ($280) ($2,552)

FY21 Unspent Funds $0 FY22 Unspent Funds ($2,552)

To other

USGS Centers Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

-Underspent Salaries is due to staff turnover at the end of the fiscal year and change in mechanism for completing work.

-Overspent Travel & Training was for travel for a cooperator to the bi-ennial conference. 

-Overspent in Operating Expenses is due to compensating contractors for data analysis.

Project L Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements
123

Project M: Leadership, Management, and Support

Goals and Objectives

During FY 2022, the budget for Project M included funding for leadership personnel including 

salaries, travel, and training for the Chief and Deputy Chief, part of the salary and travel for one 

program manager, and part of the salary for a data steward. The budget also included part of 

the salaries for a technical information specialist and a budget analyst. The vehicle section of 

the budget covers the costs associated with Department of Interior (DOI)-owned and GSAleased vehicles that USGS Grand Canyon Monitoring and Research Center (GCMRC) uses for 

travel and field work. Costs include fuel, maintenance, and repairs for DOI-owned vehicles and 

monthly lease fees, mileage costs, and repair costs for accidents and damages for GSA-leased 

vehicles. This project also includes the costs of Information Technology (IT) equipment for 

GCMRC. Salaries, travel, and training for all logistics staff are also included in this project’s 

budget. 

In addition, funding from Project M helped support the Partners in Science program with Grand 

Canyon Youth, a nonprofit organization that provides youth (ages 10-19) with educational 

experiences along the rivers and canyons of the Southwest, including the Grand Canyon. 

GCMRC scientists participated in the three Partners in Science river trips conducted in FY 2022 

during which they helped train the next generation in the scientific process, described the 

importance of science to DOI’s adaptive management efforts on the Colorado River, and 

trained them in data collection efforts in support of the FY 2021-23 Triennial Work Plan. Data 

were collected in support of understanding nutrient dynamics (Project E), aquatic algae and 

invertebrate ecology (Project F), the biology and ecology of native and nonnative fish including 

humpback chub (Projects G and I), and rainbow trout (Projects H).

Project Lead Mike Moran, Acting Chief

Principal 

Investigator(s) (PI)

Mike Moran, USGS, GCMRC

(retired)

Scott VanderKooi, USGS, SBSC

Email mjmoran@usgs.gov

Office 928-556-7289
124

Project M Budget

Logistics Budget

Burden

12.326%

Budgeted

Amount $690,221 $20,000 $178,000 $0 $0 $109,482 $997,703 

Actual

Spent $535,988 $0 $194,321 $0 $0 $90,018 $820,327 

(Over)/Under

Budget $154,233 $20,000 ($16,321) $0 $0 $19,464 $177,376 

FY21 Unspent Funds $0 FY22 Unspent Funds $177,376

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Underspent Salaries is due to staff turnover and HR delays in hiring the new GCMRC Chief.

- Underspent Travel & Training was due to travel restrictions and cancellations associated with COVID-19.

- Overspent funds in Operating Expenses is due to providing funds for shortfalls for project A and rising costs for vehicle 

maintenance and fuel.

Project M Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total

Burden

12.326%

Budgeted

Amount $269,502 $3,000 $1,074,767 $11,000 $0 $166,394 $1,524,663 

Actual

Spent $216,046 $102 $1,237,597 $18,000 $0 $179,729 $1,651,474 

(Over)/Under

Budget $53,456 $2,898 ($162,830) ($7,000) $0 ($13,335) ($126,811)

FY21 Unspent Funds $131,070 FY22 Unspent Funds $4,259

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Underspent Salaries is due to change in staff and crediting warehouse staff hours for tribal and stakeholder river trips.

- Underspent funds for Travel & Training were due to travel restrictions associated with COVID-19.

- Overspent funds in Operating Expenses is due to the rescheduled Channel Mapping river trip from project B from FY21 that 

was completed in FY22. 

- Overspent funds in Cooperative Agreements is due to the Grand Canyon Youth cooperative agreement adding an annual trip 

for tribal youth.

Logistics Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total
125

Project N: Hydropower Monitoring and Research

Goals and Objectives

The overall objective of Project N is to identify, coordinate, and collaborate with external 

partners on monitoring and research opportunities associated with operational experiments at 

Glen Canyon Dam designed to meet hydropower and energy resource objectives, as stated in 

the LTEMP Environmental Impact Statement (EIS) and its Record of Decision (ROD; U.S. 

Department of the Interior, 2016a), and the Guidance Memo (Petty, 2019). 

Operational experiments include proposed experiments in the LTEMP EIS (U.S. Department of 

Interior, 2016b) and other identified operational scenarios at Glen Canyon Dam to improve 

hydropower and energy resources, while consistent with improvement and long-term 

sustainability of other downstream resources. Project N will prioritize monitoring and research 

of proposed experiments in the LTEMP EIS and consider impacts of other proposed experiments 

on hydropower and energy as part of the experimental design. Coordinated project 

implementation and development will occur between Reclamation, Western Area Power 

Administration (WAPA), and other collaborators to utilize and build on existing hydropower and 

energy models and data, specifically from Appendix K in the LTEMP EIS (U.S. Department of 

Interior, 2016b).

Science Questions Addressed & Results

In 2021, Lucas Bair collaborated with researchers from the University of California at Davis to 

develop a quadratic programming model to optimize the production of hydropower at Glen 

Canyon Dam (GCD). The hydropower optimization model closely follows Harpman (1999). The 

hydropower operator's objective is to identify the load following path that maximizes the 

economic value (minimizes costs) in the electricity sector. This model allows researchers to 

estimate the costs of experimental flows at GCD to manage downstream physical and biological 

recourses, including under different future power system scenarios. This model will be 

published as part of the research in Project J.1. 

We assume that hydropower generated from the GCD constitutes only a small portion of the 

electricity in the Southwest region (its sole market); thus, the operator is a price-taker and 

considers prices to be exogenous and known (U.S Department of Interior, 2016b). 

Project Lead Lucas Bair

Principal 

Investigator(s) (PI) Email lbair@usgs.gov Lucas Bair, USGS, GCMRC

Telephone 928-556-7362
126

Similarly, the hourly flow through GCD is assumed to have negligible impact on reservoir 

elevation within a month. The economic cost of all near-term experimental flows are short-run 

costs. In other words, power system capacity replacement costs are not incurred because no 

reallocation of water release volumes occurs in August, when capacity is assessed (U.S 

Department of Interior, 2016b). 

Hydropower production (MW) generated at the GCD energy is a function of flow through the 

turbines and reservoir elevation, both of which are assumed to be constant over an hour time 

step. Hydropower production is subject to several operational constraints, such as the amount

of water available for release, maximum and minimum flow constraints, and ramp constraints

(see U.S. Department of Interior, 2016b for a full list of the operational constraints). 

Here we provide an example of the hydrograph that the hydropower optimization model 

generates with and without a TMF. The baseline prices used to estimate the optimal TMF 

implementation are from PLEXOS (Bain and Aker, 2019) and Aurora (U.S. Department of 

Interior, 2016b) cost production model runs for 2024. Using production cost models to estimate 

prices allows for evaluation under a variety of future fuel costs and renewable energy capacity 

expansions scenarios. These results from the hydropower optimization models (Figure 1) are 

consistent with past analysis (U.S. Department of Interior, 2016b) and can be used to identify 

the optimal (minimum costs) implementation of experiential flows that are consistent with 

achieving downstream physical and biological resource goals. 

This short-run hydropower optimization allows for an estimation of economic costs of 

experimental flows and integration of hydropower costs with predictive models of other 

resources (Project J.1). This integration is important in the assessment of cost-effective 

approaches to meet downstream resource goals and will assist in the prioritization of 

monitoring and research related to downstream resource goals. 

For a detailed description of power system modeling of hydropower in the Colorado River 

Basin, see U.S. Department of Interior, Glen Canyon Dam Long-Term Experimental and 

Management Plan Final Environmental Impact Statement, Appendix K: Hydropower systems 

technical information and analysis (U.S. Department of Interior, 2016b).

In FY 2023, GCMRC will continue to coordinate with internal and external partners, including 

Western Area Power Administration and the U.S. Department of Energy, to investigate how the 

management of GCD and the maintenance and improvement of downstream resources may 

provide opportunities to improve hydropower and energy resources. This coordination includes 

model development and application to different proposed TMF hydrographs (Giardina and 

others, in final edit with USGS Science Publishing Network) and the integration of hydropower 

costs associated with high-flow experiments and sediment resources (Mueller and Grams, 

2021; Project J.1). 
127

Figure 1. Optimal dispatch for hydropower production. Preliminary, do not cite.

References

Bain, D.M., and Acker, T.L., 2018, Hydropower impacts on electrical system production costs in 

the southwest United States: Energies, v. 11, no. 2, article 368, p. 1-21, 

https://doi.org/10.3390/en11020368. 

Bair, L.S. and Bain, D.M., 2019, Identifying the total economic value of hydropower at Glen 

Canyon Dam and implications for adaptive management, Glen Canyon Dam Adaptive 

Management Program Annual Reporting Meeting, January 13, Phoenix, AZ. 

https://www.usbr.gov/uc/progact/amp/twg/2020-01-13-twg-meeting/20200113-

AnnualReprotingMeeting-IdentifyingTotalEconomicValueHydropowerGlenCanyonDamPresentation-508-UCRO.pdf

Giardina, M.A., Korman, J., Yard, M., Wright, S., Kaplinski, M., and Bennett, G., in final edits with 

the USGS Science Publishing Network, A literature review and hypsometric analysis to 

support decisions on trout management flows on the Colorado River downstream from 

Glen Canyon Dam: U.S. Geological Survey Open-File Report.

Harpman, D.A., 1999, Assessing the short-run economic cost of environmental constraints on 

hydropower operations at Glen Canyon Dam: Land Economics, v. 75, no. 3, p. 390-401, 

https://doi.org/10.2307/3147185. 

Mueller, E.R., and Grams, P.E., 2021, A morphodynamic model to evaluate long-term sandbar 

rebuilding using controlled floods in the Grand Canyon: Geophysical Research Letters, v. 48, 

no. 9, e2021GL093007, https://doi.org/10.1029/2021GL093007. 

Petty, T.R., Secretary's Designee, Assistant Secretary for Water and Science, 2019, Glen Canyon 

Dam Adaptive Management Program guidance—August 14, 2019, memorandum: 

Washington, D.C., U.S. Department of the Interior, Office of the Secretary, 4 p. 

U.S. Department of Interior, 2016a, Record of decision for the Glen Canyon Dam long-term 

experimental and management plan final environmental impact statement (LTEMP ROD): 

Salt Lake City, Utah, U.S. Department of the Interior, Bureau of Reclamation, Upper 

Colorado Region, National Park Service, Intermountain Region, 

http://ltempeis.anl.gov/documents/docs/LTEMP_ROD.pdf. 

Date (May – July 2024)

Volume (ft3/s)

Price (USD)
128

U.S. Department of Interior, 2016b, Glen Canyon Dam Long-term Experimental and 

Management Plan final Environmental Impact Statement (LTEMP FEIS): U.S. Department of 

the Interior, Bureau of Reclamation, Upper Colorado Region, National Park Service, 

Intermountain Region, 8 chapters plus 17 appendices, 

http://ltempeis.anl.gov/documents/final-eis/. 

Waldo, S., Deemer, B.R., Bair, L.S., and Beaulieu, J.J., 2021, Greenhouse gas emissions from an 

arid-zone reservoir and their environmental policy significance—Results from existing global 

models and an exploratory dataset: Environmental Science and Policy, v. 120, p. 53-62, 

https://doi.org/10.1016/j.envsci.2021.02.006. 

Project N Budget

Project N Deliverables: Hydropower Monitoring and Research

Presentations:

Bair, L.S., and Bain, D.M., 2021, Identifying the total economic value of hydropower and 

implications for adaptive management of rivers—Operating restrictions of hydroelectric 

plants and their impacts on the operation of the Brazilian electric system—virtual 

presentation: XXIV Brazilian Symposium on Water Resources, November 2021.

Journal Articles:

Donovan, P., Reimer, M.N., Springborn, M.R., Yackulic, C.B., Bain, D.M., Bair. L.S., in prep, The 

economic cost of designer flows in river conservation.

Burden

12.326%

Budgeted

Amount $16,180 $1,500 $2,500 $0 $0 $2,487 $22,667 

Actual

Spent $18,314 $0 $0 $0 $0 $2,257 $20,571 

(Over)/Under

Budget ($2,134) $1,500 $2,500 $0 $0 $230 $2,096 

FY21 Unspent Funds $0 FY22 Unspent Funds $2,096

To other

USGS Centers Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

-Overspending Salaries is due to higher employee salary costs.

-Underspent Travel & Training is due to cancellations assocaited with COVID-19.

-Underspent funds in Operating Expenses was for software that was provided by USGS licensing at no cost to the project. 

Project N Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements
129

Project O: Is Timing Really Everything? Evaluating Resource 

Response to Spring Disturbance Flows

 Goals and Objectives

Disturbance is a critical natural process for many physical and biological resources in streams 

and rivers. High-Flow Experiments (HFEs) are the principal type of flood disturbance described 

in the Long-Term Experimental and Management Plan EIS (U.S. Department of Interior, 2016a) 

and the only approved tool for rebuilding sandbar habitats that are eroded by dam operations 

and diminished sediment supply.

For many resources, spring-timed HFEs would be ideal: the pre-dam hydrograph had snowmeltdriven spring peaks, native fish, insect, and plants have life cycles that are adapted to spring 

high flows, the main recreational boating season that drives use of sandbars for camping occurs 

in spring-summer, and strong winds that drive aeolian sand transport processes to preserve 

archaeological sites occur in spring. Yet High-Flow Experiments most often occur in fall because 

the HFE protocol in the LTEMP has narrowly defined implementation windows that do not 

allow an HFE to be triggered in the spring based on sediment inputs from the preceding year. 

The objective of Project O was to identify whether a Spring Disturbance Flow within the 

constraints of the LTEMP ROD (U.S. Department of Interior, 2016b) is a useful tool for 

enhancing LTEMP resource goals.
130

Project Elements

Element O.1. Does Disturbance Timing Affect Food Base Response?

Matrix Population Models

Damming changes the physical and chemical characteristics of a river and often eliminates 

flood disturbance, which allows invasive species that are adapted to constant flow 

environments to colonize impacted river reaches. Field experiments that test how the 

frequency and intensity of flood or low flow events affect invasive species have shown 

reductions in invasive species abundances following these disturbances. However, these studies 

are difficult to perform at ecological meaningful scales and often not replicated. Mathematical 

models offer a solution because they can predict the outcomes of various flows on invertebrate 

communities to inform management decisions. Collaborators at Oregon State University have 

developed a framework for a coupled, multi-species stage-structured model that can forecast 

how the timing, frequency, and magnitudes of flow events (i.e., extreme high and low flows 

such as occurred during the spring disturbance flow), water temperatures, and routine 

hydropower operations interact to impact native and invasive aquatic invertebrate populations 

in the Colorado River below Glen Canyon Dam. 

Model outputs can be used to extract sensitivity networks that allow further understanding of 

the specific interactions between species and the relative strengths of these interactions within 

the aquatic invertebrate assemblage. The framework will be useful for identifying flow 

management scenarios that will, for example, optimize important prey items for desired fish, 

optimize native invertebrate species’ populations, and generally characterize interspecific 

interactions between aquatic invertebrates in Grand Canyon. Of the species included in the 

model, three are invasive (Potamopyrgus antipodarum, New Zealand mud snail; Gammarus 

lacustris, amphipod; Dreissena bugensis, quagga mussel) while the other four are native taxa 

(Hydropsyche osleria, net-spinning caddisfly; Chironomidae, midges; Simuliidae, blackflies; 

Baetidae, Baetid mayflies). This multispecies mechanistic model will inform management 

discussions about invertebrate community response to novel flows caused by experimental 

flows, ongoing drought, and other flow regime shifts.

Water-Quality Monitoring at Lees Ferry

The Lees Ferry gage house is in stagnant water at flows less than 11,000 ft/s, and biological 

oxygen demand in the area is high owing to abundant submerged vegetation upstream. 

Resulting nighttime sags in dissolved oxygen at the gage are severe, such as nighttime readings 

in 2022 of < 0.5mg/L at the gage when, in reality, the main channel was 3-4mg/L dissolved 

oxygen. USGS has tried repeatedly to move sondes that are hardwired to the gage progressively 

farther into the channel to get accurate dissolved oxygen readings, but the local 

geomorphology prevents meters from being deployed in the main current. GMCRC maintains a 

sonde that is deployed from a buoy at Lees Ferry to ensure an accurate dissolved oxygen 

record, but this cannot be wirelessly connected to the gage to allow public access to the data in 

real time. 
131

To support accurate water-quality monitoring during low flows, in FY 2022 GCMRC purchased a 

new buoy and water-quality monitor that will be deployed at Lees Ferry and wirelessly 

connected to the gage house to provide real-time and publicly accessible data on dissolved 

oxygen and other parameters of interest. This equipment was not in the original proposal for 

Project O.1, but it relates to the objectives and focus of Project O, i.e., predicting and 

monitoring ecosystem response to low flows. 

Element O.2. Bank Erosion, Bed Sedimentation, and Channel Change in Western Grand Canyon

For Project O.2, Bank Erosion, Bed Sedimentation, and Channel Change in Western Grand 

Canyon, we completed processing of the channel bathymetric and lidar data that were 

collected in 2021. These data consist of five repeat surveys of the riverbed and the banks for a 

3.2 km reach beginning at RM 273. The surveys were completed in March, June, and September 

2021 and include measurements made before, during, and immediately following the high flow 

pulse of the Spring Disturbance Flow. We presented preliminary analyses showing areas of 

erosion and deposition at the January 2021 Glen Canyon Dam Adaptive Management Program 

(GCAMP) Annual Reporting Meeting. In FY 2023, we will complete analyses of these data sets 

and prepare a final report for the project.

Element O.3 Aeolian Response to a Spring Pulse Flow 

Along the Colorado River in Grand Canyon National Park, windblown river sand provides 

important wildlife habitat, sandy areas for camping, and a protective cover for archaeological 

sites but has decreased since construction of the upstream Glen Canyon Dam. One river 

management tool for increasing windblown sand is to release artificial "floods" from the dam to 

deposit sand above the level of typical river flows so it can be redistributed by wind. An 

alternative approach could be to lower river flows and expose sand that is usually underwater, 

allowing it to dry sufficiently to be moved by wind. During the 2021 spring disturbance flow we

examined whether reducing flows to a low level (stage) for five days increases windblown sand. 

We learned that 48 hours after water stage dropped, a formerly wet sandbar had dried 

sufficiently so that wind speed, rather than dry sand abundance, had become the main factor 

limiting the amount of windblown sand. After 72 hours, the ability of wind to transport sand 

from the previously submerged sandbar was equivalent to an adjacent sand dune that was 

never inundated. These results show that low steady flows combined with wind offer an 

alternative to flooding for maintaining sandy landscapes in river valleys (Sankey and others, 

2022). 

Element O.11. Decision Analysis 

Low Lake Powell levels and anticipated low flows in the Colorado River below Glen Canyon Dam 

are creating unique resource management challenges. There is a significant amount of 

uncertainty related to these conditions and impacts to downstream resources. Understanding 

the impacts to resources downstream of Glen Canyon Dam with low surface elevation at Lake 

Powell, potentially dropping below power or dead pool, and the resource trade-offs required to 

avoid dropping below these elevations is of high priority. 
132

The original FLAHG charge, and the research proposed in Project O, was to ‘evaluate 

opportunities for conducting higher spring releases that may benefit high value resources of 

concern, fill critical data gaps, and reduce scientific uncertainties.’ The low Lake Powell 

elevation has created additional challenges related to spring disturbance flows including 

moving water supply from the Upper to Lower Colorado River Basins, maintaining hydropower 

production, and minimizing the threat from warm-water invasive species. 

The objective of project O.11 is to develop modeling tools and analytical approaches to 

evaluate resource outcomes related to spring disturbance. However, the low reservoir 

elevation and possibility of sequential years of low flows in the Colorado River, along with the 

directive by the Secretaries’ designee to better understand resource management in these 

conditions, has led us to not only evaluate spring disturbance based on historical conditions, 

but also frame the decision problem to understand the dynamics between disturbance, 

resources trade-offs, and low reservoir elevations and low flows. These steps will allow the 

GCDAMP to evaluate the trade-offs that occur between resources of concern, operational 

constraints under these conditions, and the importance of monthly volumes with respect to 

spring disturbance flows. Funding was provided to GCMRC to undertake Project O.11 late in FY

2022. The funding will be used to support the objective, including collaborations with 

researchers at Utah State University who are modeling hydrology, operational alternatives, and 

future scenarios.

References

Sankey, J.B., Caster, J., Kasprak, A., and Fairley, H., 2022, The influence of drying on the aeolian 

transport of river-sourced sand: JGR Earth Surface, v. 127, no. 12, e2022JF006816, p. 1-24, 

https://doi.org/10.1029/2022JF006816. 

U.S. Department of Interior, 2016a, Glen Canyon Dam Long-term Experimental and 

Management Plan final Environmental Impact Statement (LTEMP FEIS): U.S. Department of 

the Interior, Bureau of Reclamation, Upper Colorado Region, National Park Service, 

Intermountain Region, online, http://ltempeis.anl.gov/documents/final-eis/.

U.S. Department of Interior, 2016b, Record of decision for the Glen Canyon Dam long-term 

experimental and management plan final environmental impact statement (LTEMP ROD): 

Salt Lake City, Utah, U.S. Department of the Interior, Bureau of Reclamation, Upper 

Colorado Region, National Park Service, Intermountain Region, 

http://ltempeis.anl.gov/documents/docs/LTEMP_ROD.pdf. 
133

Project O Budget

Project O Deliverables: Is Timing Really Everything? Evaluating Resource Response 

to Spring Disturbance Flows 

Presentations:

Bair, L.S. and Neher, C., 2022, Recreational anglers’ preferences for flow attributes—Taking 

advantage of a designer flow to validate novel scenarios—virtual presentation: The 

International Institute of Fisheries Economics & Trade, Vigo, Spain, July 18-22, 2022.

Kennedy, T., Deemer, B., Lytle, D., Grams, P., Sankey, J., Butterfield, B., Dibble, K., Tusso, R., and 

Bair, L., 2022, Spring disturbance flow update—virtual presentation: Glen Canyon Dam 

Adaptive Management Program Annual Reporting Meeting, January 2022. 

Kennedy, T., Deemer, B., Lytle, D., Grams, P., Sankey, J., Butterfield, B., Dibble, K., Tusso, R., and 

Bair, L., 2022, Spring disturbance flow update—virtual presentation: Glen Canyon Dam 

Adaptive Management Program Adaptive Management Work Group Meeting, February 

2022.

Kurthen, A.L, Lytle, D.A., and Kennedy, T.A., 2022, Developing a mechanistic modeling 

framework for aquatic invertebrate communities in dammed rivers: Joint Aquatic Sciences 

Meeting (JASM 2022), Grand Rapids, MI, May 2022. 

Journal Articles:

Butterfield, B.J. and Palmquist, E.C., in review, Divergent physiological responses of hydric and 

mesic riparian plant species to a Colorado River experimental flow: Plant Ecology.

Sankey, J.B., Caster, J., Kasprak, A., and Fairley, H., 2022, The influence of drying on the aeolian 

transport of river-sourced sand: JGR Earth Surface, v. 127, no. 12, e2022JF006816, p. 1-24, 

https://doi.org/10.1029/2022JF006816. 

Burden

12.326%

Budgeted

Amount $230,993 $12,000 $5,000 $25,885 $40,667 $31,344 $345,889 

Actual

Spent $50,443 $1,411 $25,047 $168,500 $0 $14,534 $259,935 

(Over)/Under

Budget $180,550 $10,589 ($20,047) ($142,615) $40,667 $16,810 $85,954 

FY21 Unspent Funds $0 FY22 Unspent Funds $85,954

Project O Salaries Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Project O is entirely funded through FY21 unspent funds.

- Underspent Salaries were covered by USGS employees as well as through CESU cooperative agreements with Oregan State 

University and Utah State University.

-Overspent Operating Expenses is a contract with Marda Science for Riverbed Vegetation mapping awarded in FY22 instead of 

FY21.

-Overspent amount in Cooperative Agreement is due to change in mechanism for completing work through CESU cooperative 

agreements.
134

Appendix 1: Lake Powell Water-Quality Monitoring

Lake Powell received 6.1 million acre feet (maf, 64% of the 1991-2021 average) of unregulated 

inflow in water year (WY) 2022. This included approximately 500 thousand acre-feet (kaf) of 

water from Flaming Gorge Reservoir under the Drought Contingency Plan. In comparison, 

inflow observed in WY 2021 was 3.5 maf (36% of the 1991-2021 average), the second driest 

year on record after 2002. At the end of WY 2022, Lake Powell’s surface elevation was 3529.33 

feet (171 feet from full pool) with a storage of 5.80 maf, or 25% of live capacity. This is down 

from the end of WY 2021 when surface elevation was 3545.98 ft and storage was 7.27 maf. 

Releases for WY 2022 totaled 7 maf (as compared to 8.23 in WY 2021) consistent with 

operations under the 2007 Interim Guidelines. Operations for WY 2023 will fall under the Lower 

Elevation Balancing Tier, where Lake Powell and Lake Mead will balance contents with Glen 

Canyon Dam (GCD) release volumes no less than 7.0 maf and no more than 9.5 maf. The total 

projected annual release volume is currently 7.0 maf, with the October most probable (median) 

forecast projecting 8.1 maf of annual inflow to Lake Powell in WY 2023 (84% of average). 

Reclamation will evaluate hydrologic conditions in April 2023 to determine if balancing releases 

may be appropriate under the conditions established in the 2007 Interim Guidelines. 

Glen Canyon Dam releases temperatures reached a record maximum of 21.1 °C on September 

22, 2022 (Figure 2), which is markedly warmer than the peak of 16.8 °C on September 22, 2021, 

and unprecedented in the last 50 years (Figure 1). Prior to 2022, the peak instantaneous water 

temperature measured at Lees Ferry had not exceeded 17.2°C in over 50 years. This year the 

peak Lees Ferry water temperature measured was 21.4°C. These high temperatures are 

consistent with a recent trend wherein peak temperatures in GCD releases have exceeded 15 °C 

in 5 of the 8 previous years. Still, the Glen Canyon release temperatures in 2022 are 

unprecedented. Specifically, the 122 daily average water temperatures recorded at Lees Ferry 

between June 23 and October 22, 2022, were the warmest 122 water temperatures recorded in 

the preceding 50 years. These historically warm water temperatures, combined with relatively 

low soluble reactive phosphorus concentrations, are projected to cause a collapse in the 

rainbow trout fishery as soon as next year if low water levels continue (Korman and others,

2022). The warm waters also increase the likelihood of establishment of nonnative smallmouth 

bass and other warm-water nonnative fish below Glen Canyon Dam, which poses a serious 

threat to conservation of native fish (Bruckerhoff and others, 2022).

Program Manager (PM) Bridget Deemer

Principal 

Investigator(s) (PI)

Bridget Deemer, USGS, GCMRC

Nick Voichick, USGS, GCMRC

Tom Sabol, USGS, GCMRC

Caitlin Andrews, USGS, GCMRC

Bryce Mihalevich, USGS, 

GCMRC

Email bdeemer@usgs.gov

Telephone 360-606-4353
135

In the summer of 2022, layers of low dissolved oxygen water developed in all three major 

tributary arms of Lake Powell (Colorado, the San Juan, and Escalante Rivers). Similar low 

dissolved oxygen events have developed in the past (namely in 2005, 2014, 2019, and 2021). 

This low dissolved oxygen was advected toward the forebay, with a minimum dissolved oxygen 

concentration of about 0.4 mg/L at 20 m depth in October 2022. This advection resulted in 

record low concentrations of DO in the GCD tailwaters (minimum DO of 2.5 mg/L in September 

of 2022 as compared with 4.0 mg/L in Octobers of 2019 and 2021, 4.4 mg/L in October 2014, 

and 3.5 mg/L in 2005; Figure 1). The 2005 low dissolved oxygen event coincided with much 

lower recruitment and growth in the Glen Canyon rainbow trout fishery (Korman and others, 

2012), so the low dissolved oxygen observed in Glen Canyon is of concern. The National Park 

Service continues to track and monitor the quagga mussel population throughout Lake Powell, 

mainly by estimating veliger densities in zooplankton tows. 

Summary of FY 2022 Accomplishments

In fiscal year (FY) 2022, the GCMRC collected physical, biological, and chemical data and 

samples from Lake Powell, GCD, and Lees Ferry. This included four reservoir-wide surveys in 

collaboration with Reclamation as well as nine complete forebay surveys (Table 1). GCMRC also 

checked, reprogrammed, and replaced temperature and conductivity loggers on a thermistor 

string that is deployed off the buoy line near GCD in March of 2022 (and again in October of 

2022). 

GCMRC continued development of a Microsoft SQL Server database and a linked custom 

application that allows for streamlined data import, export, and online data visualization. In 

August of 2021, USGS submitted a U.S. Geological Survey ScienceBase data release (Andrews 

and Deemer, 2022) and an associated data paper (Deemer and others, 2023) describing the 

long-term water-quality monitoring data set (Deemer and others, 2023). The ScienceBase data

set is a dynamic data release containing 8 flat files (Figure 2) that is structured so that it can be 

regularly updated with new data as it becomes available and undergoes QA/QC and 

normalization procedures (Andrews and Deemer, 2022). USGS plans to update this repository 

annually. The database is also linked to Tableau and USGS scientists are currently developing 

data visualizations to share with their colleagues at Reclamation (Hensleigh and others, 2022), 

with the eventual intention to make some visualizations public with the data release. 

In FY 2022, GCMRC also continued to maintain the sonde directly below GCD for near-real-time 

data transmission to USGS GCMRC’s Amazon Web Services platform. These data are then linked 

to Tableau, an online data visualization platform, which is currently being shared with colleagues 

at Reclamation as well as several interested stakeholders (see Project K for more information). 

Efforts are underway to make this visualization public (Gushue and Thomas, 2021).

Postdoctoral researcher, Bryce Mihalevich, began working for GCMRC in June of 2022 with the 

goal of improving the Lake Powell CE-QUAL-W2 model. Mihalevich and Deemer attended a CEQUAL-W2 workshop held at Portland State University from June 20-24, 2022. 
136

As of October 2022, a new grid structure has been developed that reflects a new bathymetric 

data set for Lake Powell (Jones and Root, 2021) and that performs under low reservoir water 

levels. Mihalevich is currently continuing to develop the CE-QUAL-W2 model to improve 

meteorological inputs and to incorporate long-term water-quality data. Deemer also conducted 

water and sediment incubations with dry deltaic sediments in FY 2022 to examine controls on 

oxygen consumption and phosphorus release with funding from outside the Lake Powell 

program. These findings will be used to inform the dissolved oxygen module of the CE-QUAL-W2 

model.

During FY 2022, PI Deemer worked with Technical Information Specialist, Meredith Hartwell, to 

develop a website for the Lake Powell Water-Quality Monitoring Program 

(https://www.usgs.gov/centers/southwest-biological-science-center/science/lake-powellresearch). The page provides some basic facts about Lake Powell, describes the ongoing waterquality monitoring program, and describes some active areas of current research. We plan to 

use this page as a launching point for publicly available data visualizations once the data release 

is finalized. 

Funding Note

The Lake Powell monitoring program was designed to determine status and trends of the 

water-quality of Lake Powell and GCD releases, determine the effect of climate patterns, 

hydrology, and dam operations on reservoir hydrodynamics and the water-quality of GCD 

releases, and provide predictions of future conditions. Since 1997, GCMRC has conducted a 

long-term water-quality monitoring program of Lake Powell and Glen Canyon Dam releases in 

collaboration with the Bureau of Reclamation (Reclamation) and National Park Service (NPS). 

This project has been funded entirely by Reclamation from power revenues and receives no 

monetary support from the Glen Canyon Dam Adaptive Management Program (GCDAMP). In 

addition to direct funding of the program, Reclamation also provides support for laboratory 

analyses. 

An interagency agreement was signed in FY 2018, which has supported GCMRC involvement in 

the Lake Powell Water-Quality Monitoring program over the past five years. A scope of work 

and budget is currently drafted toward the development of a new interagency agreement. In 

addition, in FY 2022 a separate scope of work was funded by Reclamation under the oversight 

of Clarence Fullard, titled Leveraging Existing Data and Improving Existing Models to Better 

Bound Possible Water-Quality Futures for Lake Powell and Its Tailwater. Funding for FY 2022 

was appended to the original Interagency Agreement and additional funding for FY 2023 is 

planned.
137

Table 1. Beginning dates and sampling activity for the Lake Powell water-quality monitoring for FY 2022. 

Date Sampling Activity

10/20/21 Forebay, draft tubes, Lees Ferry

11/17/21 Forebay, draft tubes, Lees Ferry

12/13/21 Quarterly Survey

1/12/22 Forebay, draft tubes, Lees Ferry

2/9/22 Forebay, draft tubes, and Lees Ferry

3/7/22 Quarterly Survey

4/19/22 Forebay, draft tubes, and Lees Ferry

5/16/22 Forebay, draft tubes, and Lees Ferry

06/13/22 Quarterly survey

7/26/22 Forebay, draft tubes, and Lees Ferry

8/26/22 Forebay, draft tubes, and Lees Ferry

9/19/22 Quarterly survey
138

Figure 1. Water-quality record from Glen Canyon Dam near Page, AZ (gage #09379901; U.S. Geological Survey, 2022), for

temperature (A) and dissolved oxygen (B) as well as conductivity data from the Colorado River at Lees Ferry (gage # 09380000;

panel C). Black points show daily median values from 2022 and black bars show minimum and maximum values for each day in 

2022 from the continuous data record (logging at 15-minute increments). Lines and bands show the 13-year median value for 

each parameter and the red, blue, and gray color bands represent the daily 10th and 90th quantiles of 13-year temperature, 

dissolved oxygen, and conductivity, respectively.
139

Figure 2. Schema diagram showing the eight flat files that comprise the Lake Powell data set being released (Andrews and 

Deemer 2022; Deemer and others, 2023).

References

Andrews, C.M., and Deemer, B.R., 2022, Limnology data from Lake Powell, desert southwest 

USA: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZIKVYW. 

Bruckerhoff, L.A., Wheeler, K., Dibble, K.L., Mihalevich, B.A., Neilson, B.T., Wang, J., Yackulic, 

C.B., and Schmidt, J.C., 2022, Water storage decisions and consumptive use may constrain 

ecosystem management under severe sustained drought: Journal of American Water 

Resources Association, v. 58, no. 5, p. 654-672, https://doi.org/10.1111/1752-1688.13020. 

Deemer, B.R., Andrews, C.M., Strock, K.E., Voichick, N., Hensleigh, J., Beaver, J.R., and Radtke, 

R., 2023, Over half a century record of limnology data from Lake Powell, desert southwest 

United States: From reservoir filling to present day (1964–2021): Limnology and 

Oceanography Letters, online, https://doi.org/10.1002/lol2.10310. 
140

Gushue, T.M, Thomas, J.E., 2021, Daily water-quality data at Glen Canyon Dam—online data 

visualization: U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon

Monitoring and Research Center,

https://tableau.usgs.gov/t/InternalGuestAccess/views/WaterQualityatGlenCanyonDam/Dail

yWaterQualityDataatGlenCanyonDam?%3Aembed=y&%3AisGuestRedirectFromVizportal=y

#1. 

Hensleigh, J., Andrews, C.M., Voichick, N., and Deemer, B., 2022, Lake Powell vertical waterquality profiles— online data visualization: U.S. Geological Survey, Southwest Biological 

Science Center, Grand Canyon Monitoring and Research Center, 

https://tableau.usgs.gov/views/view-profiles-by-station-collectiondate/ProfileByStationVisitDateDashboard?%3Aembed=y&%3AisGuestRedirectFromVizporta

l=y

Jones, D.K., and Root, J.C., 2021, Modified topobathymetric elevation data for Lake Powell: U.S. 

Geological Survey data release, https://doi.org/10.5066/P9H60YCF. 

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related 

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Korman, J., Martell, S.J.D., Walters, C.J., Makinster, A.S., Coggins, L.G., Yard, M.D., and Person, 

W.R., 2012, Estimating recruitment dynamics and movement of rainbow trout 

(Oncorhynchus mykiss) in the Colorado River in Grand Canyon using an integrated 

assessment model: Canadian Journal of Fisheries and Aquatic Sciences, v. 69, no. 11, p. 

1827-1849, http://doi.org/10.1139/f2012-097. 

U.S. Geological Survey, 2022, National Water Information System: U.S. Geological Survey web 

interface, https://doi.org/10.5066/F7P55KJN. Cited November 2022 at 

https://waterdata.usgs.gov/nwis. 
141

Appendix 1 Budget

Appendix 1 Deliverables: Lake Powell Water-Quality Monitoring

Presentations:

Deemer, B.R., 2022, Beyond eco-flows—Understanding biogeochemical links between 

limnology and management in human-made reservoirs—presentation: Joint Aquatic Science 

Meeting (JASM 2022), Grand Rapids, MI, USA.

Journal Articles:

Deemer, B.R., Andrews, C.M., Strock, K.E., Voichick, N., Hensleigh, J., Beaver, J.R., and Radtke, 

R., 2023, Over half a century record of limnology data from Lake Powell, desert southwest 

United States: From reservoir filling to present day (1964–2021): Limnology and 

Oceanography Letters, online, https://doi.org/10.1002/lol2.10310. 

USGS Data Releases:

Andrews, C.M., and Deemer, B.R., 2022, Limnology data from Lake Powell, desert southwest 

USA: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZIKVYW. 

Web Content and Applications:

Deemer, B.R., 2022, Lake Powell research—webpage: U.S. Geological Survey Southwest 

Biological Science Center, Grand Canyon Monitoring and Research 

Center, https://www.usgs.gov/centers/southwest-biological-science-center/science/lakepowell-research. 

Burden

20.163%

Budgeted

Amount $145,065 $8,814 $11,968 $0 $0 $33,440 $199,287 

Actual

Spent $188,290 $5,699 $24,507 $0 $0 $44,055 $262,551 

(Over)/Under

Budget ($43,225) $3,115 ($12,539) $0 $0 ($10,615) ($63,264)

 Unspent Funds $63,264 2022 Unspent Funds $0

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- This project is funded entirely by Reclamation with non-GCDAMP funding.

- This agreeemnt period of performance ended 12/31/2022 and shows all funding expended through the calendar year. 

- Overspent Salaries is due to this agreement being on the calendar year rather than the fiscal year and actual salary 

overspending is between 9/30/22 and 12/31/2022 when the agreement ended. 

- Underspent Travel & Training were due to travel restrictions associated with COVID-19.

-Overspent Operating Expenses is for a Sonde and equipment purchase that was made after the fiscal year. 

-All funds have been expended at the end of the calendar year and a new 5 year agreeement start date is 1/1/2023-12/31/2027

Lake Powell (NOT GCDAMP funded)

Salaries Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers

Total
142

Gushue, T.M, Thomas, J.E., 2021, Daily water-quality data at Glen Canyon Dam—online data 

visualization: U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon

Monitoring and Research Center,

https://tableau.usgs.gov/t/InternalGuestAccess/views/WaterQualityatGlenCanyonDam/Dail

yWaterQualityDataatGlenCanyonDam?%3Aembed=y&%3AisGuestRedirectFromVizportal=y

#1. 

Hensleigh, J., Andrews, C.M., Voichick, N., and Deemer, B., 2022, Lake Powell vertical waterquality profiles— online data visualization: U.S. Geological Survey, Southwest Biological 

Science Center, Grand Canyon Monitoring and Research Center, 

https://tableau.usgs.gov/views/view-profiles-by-station-collectiondate/ProfileByStationVisitDateDashboard?%3Aembed=y&%3AisGuestRedirectFromVizporta

l=y.
143

Appendix 2: Deliverables (Products), All Projects

Project A Deliverables: Streamflow, Water Quality, and Sediment Transport and 

Budgeting in the Colorado River Ecosystem

Presentations:

Because the COVID-19 pandemic is only now ending, no presentations were made at 

professional scientific meetings during FY 2022. One presentation was made to the GCDAMP at 

the January 2022 Annual Reporting Meeting.

Journal Articles:

Deemer, B.R., Yackulic, C.B., Hall, R.O., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J., Topping, 

D.J., Voichick, N., and Yard, M., 2022, Daily flow fluctuations associated with hydropower 

generation reduce gross primary productivity up to 400 kilometers downstream in a 

regulated river: Proceedings of the National Academy of Sciences NEXUS, v. 1, p. 1–12, 

https://doi.org/10.1093/pnasnexus/pgac094.

LeCoz, J., Perret, E., Camenen, B., Topping, D.J., Buscombe, D.D., Leary, K.C.P, Dramais, G., and 

Grams, P.E., in press, Mapping 2-D bedload rates throughout a sand-bed river reach from 

high-resolution acoustical surveys of migrating bedforms: Water Resources Research, 

https://doi.org/10.1029/2022WR032434.

USGS Reports:

Griffiths, R.E., Topping, D.J., and Unema, J.A., in review, Changes in sand storage in the Colorado 

River in Grand Canyon National Park from July 2017 through June 2020: U.S. Geological 

Survey Open-File Report.

Sabol, T.A., Topping, D.J., Griffiths, R.E., and Dramais, G., 2022, Field investigation of subisokinetic sampling by the US D-96-type suspended-sediment sampler and its effect on 

suspended-sediment measurements: U.S. Geological Survey Open-File Report 2022-1077, 

14 p., https://doi.org/10.3133/ofr20221077.

Topping, D.J., Hazel, J.E., Jr., Kaplinski, M., and Grams, P.E., in press at the USGS Science 

Publishing Network, Resurvey of the Marble Canyon and Bridge Canyon dam sites in Grand 

Canyon National Park—Dam-induced changes in sediment storage and evidence supporting 

recent pre-dam bedrock incision: U.S. Geological Survey Professional Paper.

Web Applications:

• https://www.gcmrc.gov/discharge_qw_sediment/ - Stage, discharge, sediment 

transport, water-quality, and sand-budget data are served through the USGS-GCMRC

website. The database associated with this website is updated every day to month, 

depending on data type. This web-based application has been maintained to provide 

stakeholders, scientists, and the public with the ability to perform interactive online

data visualization and analysis, including the on-demand construction of sand budgets 

and duration curves. These capabilities are unique in the world. 
144

• https://waterdata.usgs.gov/nwis - Stage, discharge, and water-quality data collected at

9 gaging stations by the USGS Utah and Arizona Water Science Centers are posted to

this website every hour.

Project B Deliverables: Sandbar and Sediment Storage Monitoring and Research

Presentations:

Grams, P.E., 2022, The effects of high-flow experiments and dam releases on sandbar erosion 

and deposition in Marble and Grand canyons: Glen Canyon Dam Adaptive Management 

Program Annual Reporting Meeting, January 2022.

Grams, P.E., 2022, Sediment dynamics in western Grand Canyon during 2021 Spring disturbance 

flow: Glen Canyon Dam Adaptive Management Program Annual Reporting Meeting, January 

2022.

Grams, P.E., 2022, Summary of sediment and sandbar projects—GCMRC Projects A and B, 

LTEMP Goal 7: Glen Canyon Dam Adaptive Management Program Adaptive Management 

Work Group Meeting, February 2022.

Grams, P.E. and Mueller, E.R., 2022, Predicted effects of alternative summer 2022 release 

scenarios on sediment and sandbars: Glen Canyon Dam Adaptive Management Program

Webinar on Glen Canyon Dam Summer 2022 Release Pattern, March 2022.

Grams, P.E., 2022, Multi-decadal sandbar response to flow management downstream from a 

large dam—The Colorado River in Marble and Grand canyons, Arizona: Glen Canyon Dam 

Adaptive Management Program Adaptive Management Work Group Meeting, August 2022.

Mueller, E.R., and Grams P.E., 2021, A morphodynamic model to evaluate long-term sandbar 

rebuilding using controlled floods: Glen Canyon Dam Adaptive Management Program

Technical Work Group Meeting, October 2021.

USGS Reports:

Hazel, J.E., Kaplinski, M.A., Hamill, D., Buscombe, D., Mueller, E.R., Ross, R.P., Kohl, K., and 

Grams, P.E., 2022, Multi-decadal sandbar response to flow management downstream from 

a large dam—The Glen Canyon Dam on the Colorado River in Marble and Grand Canyons, 

Arizona: U.S. Geological Survey Professional Paper 1873, prepared in cooperation with 

Northern Arizona University, 104 p., https://doi.org/10.3133/pp1873. 

Kaplinski, M., Hazel, J.E., Jr., Grams, P.E., Gushue, T.M., Buscombe, D., and Kohl, K., 2022, 

Channel mapping of the Colorado River from Glen Canyon Dam to Lees Ferry in Glen Canyon 

National Recreation Area, Arizona: U.S. Geological Survey Open-File Report 2022-1057, 20 

p., https://doi.org/10.3133/ofr20221057. 

USGS Data Releases:

Kaplinski, M., Hazel, J.E. Jr, Grams, P.E., Gushue, T., Buscombe, D.D., and Kohl, K., 2022, Channel 

mapping Glen Canyon Dam to Lees Ferry in Glen Canyon National Recreation Area, Arizona - 

Data: U.S. Geological Survey data release, https://doi.org/10.5066/P98GFP93. 
145

Web Applications:

Sandbar Monitoring Data: http://www.gcmrc.gov/sandbar

(https://www.usgs.gov/apps/sandbar/) 

Remote Camera Sandbar Photographs: http://www.gcmrc.gov/sandbar

(https://grandcanyon.usgs.gov/gisapps/sandbarphotoviewer/RemoteCameraTimeSeries.ht

ml) 

Grand Canyon River Guides Adopt-a-Beach Photographs: http://www.gcmrc.gov/sandbar

(https://grandcanyon.usgs.gov/gisapps/adopt-a-beach/index.html) 

Project C Deliverables: Riparian Vegetation Monitoring and Research

Presentations:

Butterfield, B.J. and Palmquist, E.C., 2022, Riparian vegetation monitoring and modeling—

presentation: Glen Canyon Dam Adaptive Management Program Annual Reporting Meeting, 

January 12, 2022.

Butterfield, B.J., Palmquist, E.C., and Yackulic, C.B., 2022, The hydroclimatic niche—A tool for 

predicting and managing riparian plant community responses to streamflow seasonality—

presentation: 16th Biennial Conference of Science & Management on the Colorado Plateau 

& Southwest Region, September 12-15, 2022, Flagstaff, AZ.

Kennedy, T., Deemer, B., Lytle, D., Grams, P., Sankey, J., Butterfield, B.J., Dibble, K., Bair, L., and 

Tusso, R., 2022, Disturbance Flow Panel Session—presentation: Glen Canyon Dam Adaptive 

Management Program Annual Reporting Meeting, January 12, 2022.

Palmquist, E., Ogle, K., Butterfield, B.J., Whitham, T., Shafroth, P., and Allan, G., Provenance of a 

riparian shrub changes traits but not flood response under a common climatic setting:

River's Edge West 20th Anniversary Riparian Restoration Conference, February 23-25, 2022, 

Grand Junction, CO.

Palmquist, E.C., 2022, Goal 11: Riparian Vegetation Draft Metrics—presentation: Glen Canyon 

Dam Adaptive Management Program Technical Work Group Meeting, April 13, 2022.

Palmquist, E.C., Ogle, K., and Butterfield, B.J., Riparian plant presence and abundance are 

differentially controlled by hydrology and temperature along a regulated, dryland river—

presentation: 16th Biennial Conference of Science & Management on the Colorado Plateau 

& Southwest Region, September 12-15, 2022, Flagstaff, AZ.

Pilkington, L., Stevens, L., Burke, K., Butterfield, B.J., Palmquist, E., and Sankey, J., 2022, Riparian 

vegetation science & management—webinar presentation: Glen Canyon Dam Adaptive 

Management Program Adaptive Management Work Group Meeting, February 9-10, 2022, 

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

Research Center, https://www.usbr.gov/uc/progact/amp/amwg.html. 

Journal Articles:

Butterfield, B.J., Palmquist, E.C., and Yackulic, C.B., 2022, The hydroclimate niche—A tool for 

predicting and managing riparian plant community responses to streamflow seasonality: 

River Research and Applications, v. 39, no. 1, p. 84-94, https://doi.org/10.1002/rra.4067. 
146

Samuels-Crow, K., Ogle, K., and Palmquist, E.C., 2022, What drought means for southwestern 

landscapes: Boatman's Quarterly Review, v. 35, no. 1, p. 16-19. (Article not available online)

USGS Data Releases:

Palmquist, E.C., Ralston, B.E., Sarr, D., Merritt, D.M., Shafroth, P.B., Scott, J.A., 2017, 

Southwestern riparian plant trait matrix, Colorado River, Grand Canyon, Arizona (ver. 2.0, 

January 2022): U.S. Geological Survey data release, https://doi.org/10.5066/P974VCDK. 

Palmquist, E.C., Butterfield, B.J., and Ralston, B.E., 2022, Riparian vegetation data downstream 

of Glen Canyon Dam in Glen Canyon National Recreation Area and Grand Canyon National 

Park, AZ, from 2014 to 2019: U.S. Geological Survey data release, 

https://doi.org/10.5066/P9KEHY2S. 

Project D Deliverables: Geomorphic Effects of Dam Operations and Vegetation 

Management for Archaeological Sites 

Presentations:

Fairley, H.C., Scott, M., and Fairley, A.H., 2022, Assessing 50 years of change in riparian 

condition along the Colorado River in Grand Canyon, Arizona—presentation: 16th Biennial 

Conference on Science and Management, Flagstaff, AZ, September 15, 2022. 

Sankey, J.B., East, A., Fairley, H.C., Dierker, J., Brennan, E., Bransky, N., 2022, Risk of erosion of 

archaeological sites along the Colorado River in Grand Canyon owing to long term 

operations of Glen Canyon Dam—presentation: 16th Biennial Conference on Science and 

Management, Flagstaff, AZ, September 15, 2022. 

Papers and Reports:

Caster, J., Sankey, J.B., Fairley, H., and Kasprak, A., 2022, Terrestrial lidar monitoring of the 

effects of Glen Canyon Dam operations on the geomorphic condition of archaeological sites 

in Grand Canyon National Park, 2010–2020: U.S. Geological Survey Open-File Report 2022–

1097, 100 p., https://doi.org/10.3133/ofr20221097. 

Pilkington, L., Sankey, J.B., Boughter, D., Preston, T., Prophet, C.C., 2022, Parks look for ways to 

alleviate Glen Canyon Dam’s dramatic downstream impacts: Park Science Magazine, 

National Park Service, Glen Canyon National Recreation Area, Grand Canyon National Park, 

v. 36, no. 1, Summer 2022, https://www.nps.gov/articles/000/parks-look-for-ways-toalleviate-glen-canyon-dams-downstream-impacts.htm. 

Sankey, J.B., Caster, J., Kasprak, A. and Fairley, H., 2022, The influence of drying on the aeolian 

transport of river-sourced sand: Journal of Geophysical Research: Earth Surface, v. 127, no. 

12, e2022JF006816, p. 1-24, https://doi.org/10.1029/2022JF006816. 
147

Project E Deliverables: Controls on Ecosystem Productivity: Nutrients, Flow and 

Temperature

Presentations:

Bruckerhoff, L., Wheeler, K., Dibble, K., Mihalevich, B., Neilson, B., Wang, J., Yackulic, C., and 

Schmidt, J., 2022, Water storage decisions and consumptive use constrain ecosystem 

management under severe sustained drought—virtual presentation: Desert Fishes Council 

2022 Annual Meeting, St. George, Utah.

Deemer, B.R., 2022, Beyond eco-flow—Understanding biogeochemical links between limnology 

and management in human-made reservoirs—presentation: Joint Aquatic Science Meeting

(JASM 2002), Grand Rapids, MI.

Deemer, B.R., Reibold, R., Fatta, A., Corman, J., Yackulic, C.B., and Reed, S., 2022, Links between 

drought and river nutrition—Phosphorus export from Glen Canyon Dam under declining 

reservoir elevations—presentation: 16th Biennial Conference of Science and Management 

on the Colorado Plateau and Southwest Region, Flagstaff, AZ.

Deemer, B., Yackulic, C., Hall, R., Dodrill, M., Kennedy, T., Muehlbauer, J., Topping, D., Voichick, 

N., and Yard, M., 2022, Turning the red river green: An experimental flow increases primary

production in the Colorado River—presentation for Friday’s Findings webinar, U.S. 

Geological Survey Ecosystems Mission Area, Reston, Va., January 14, 2022, U.S. Geological 

Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research 

Center.

Dibble, K.L., 2022, Aquatic plants, food webs, and fish populations in the Colorado River in Glen 

Canyon Dam National Recreation Area—Outreach river trip and science presentation to the 

2022 Native Youth Science Camp, Flagstaff, AZ.

Dibble, K.L., Bruckerhoff, L.A., Yackulic, C.B., Schmidt, J.C., Bestegen, K.R., Kennedy, T.A., 

Mihalevich, B.A., Neilson, B.T., Wang, J., and Wheeler, K., 2022, Forecasting the influence of 

climate change, water storage decisions, and consumptive use on fishes of the Colorado 

River basin—Oral presentation and virtual panel for the Department of Interior’s Turbine 

Talk Webinar Series focused on ‘USGS Science on Climate Impacts on Hydropower’. 

Dibble, K.L., Yard, M., Tusso, R., and Buscombe, D., 2022, Aquatic vegetation in Glen Canyon—

Observations following a spring disturbance flow—presentation: Glen Canyon Dam 

Adaptive Management Program Annual Reporting Meeting, January 11-12, 2022, Southwest 

Biological Science Center, Grand Canyon Monitoring and Research Center. 

Hansen, L.E., and Yackulic, C.B., 2022, Linking ecosystem processes to consumer growth rates—

Gross primary productivity and temperature drive fish growth—presentation: Joint Aquatic 

Science Meeting (JASM 2002), Grand Rapids, MI.

Journal Articles:

Deemer, B.R., Reibold, R., Fatta, A., Corman, J.R., Yackulic, C.B., and Reed, S.C., submitted, pH of 

dam releases affects downstream phosphorus cycling in an arid regulated river: Ecological 

Applications. 
148

Deemer, B.R., Yackulic, C.B., Hall, R.O., Jr., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J.D., 

Topping, D.J., Voichick, N., and Yard, M.D., 2022, Experimental reductions in sub-daily flow 

fluctuations increased gross primary productivity for 425 river kilometers downstream: 

PNAS Nexus, v. 1, no. 3, pgac094, https://doi.org/10.1093/pnasnexus/pgac094.

Hansen, L.E., Yackulic, C.B., Dickson, B.G., Deemer, B.R., and Best, R.J., submitted, Linking 

ecosystem processes to consumer growth rates—Gross primary productivity as a driver of 

freshwater fish somatic growth in a resource-limited river: Canadian Journal of Fisheries and 

Aquatic Sciences.

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related 

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Yard, M.D., Yackulic, C.B., Korman, J., Dodrill, M.J., and Deemer, B.R., 2023, Declines in prey 

production during the collapse of a tailwater rainbow trout population are associated with 

changing reservoir conditions: Transactions of the American Fisheries Society, v. 152, no. 1, 

p. 35-50, https://doi.org/10.1002/tafs.10381. 

USGS Data Releases:

Deemer, B.R., Yard, M.D., Voichick, N., Goodenough, D.C., Bennett, G.E., Hall Jr., R.O., Dodrill, 

M.J., Topping, D.J., Gushue, T., Muehlbauer, J.D, Kennedy, T.A., and Yackulic, C.B., 2022, 

Gross primary production estimates and associated light, sediment, and water quality data 

from the Colorado River below Glen Canyon Dam: U.S. Geological Survey data release, 

https://doi.org/10.5066/P9ZS6YLV. 

Hansen, L.E., and Yackulic, C.B., 2022, Mark-recapture and environmental data used to predict 

flannelmouth sucker (Catostomous latippinis) growth rates within the Colorado River in the 

Grand Canyon from April 2012 to October 2018: U.S. Geological Survey data release, 

https://doi.org/10.5066/P9852I1G. 

Yackulic, C. B., M. D. Yard, J. Korman, M. J. Dodrill, and B. R. Deemer. 2022. Proximal and distal 

factors associated with the decline in secondary invertebrate prey production in the 

Colorado River, Glen Canyon, Arizona: U.S. Geological Survey data release, 

https://doi.org/10.5066/P9UZTYPV. 

Project F Deliverables: Aquatic Invertebrate Ecology

Presentations:

Kennedy, T., 2022, Background and design of the Bug Flows hydrograph—virtual presentation: 

Science Advisor review of the Bug Flow experiment, Day 1, October 2022.

Kennedy, T., 2022, Bug Flows and the rainbow trout fishery—virtual presentation: Science 

Advisor review of the Bug Flow Experiment, Day 1, October 2022. 
149

Kennedy, T., 2022, Discussion of the Bug Flow synthesis and review and opportunities for Spring 

and Summer Flow Experiments—virtual presentation: Glen Canyon Dam Adaptive 

Management Program Technical Work Group Meeting, January 2022, Southwest Biological 

Science Center, Grand Canyon Monitoring and Research Center. 

Kennedy, T., 2022, Potential next steps in flow experimentation—virtual presentation: Science 

Advisor review of the Bug Flow Experiment, Day 2, November 2022. 

Kennedy, T., and Muehlbauer, J., 2022, Project F—Aquatic ecology and food base monitoring—

virtual presentation: Glen Canyon Dam Adaptive Management Program Annual Reporting 

Meeting, January 11-12, 2022, Southwest Biological Science Center, Grand Canyon 

Monitoring and Research Center. 

Kennedy, T. and Muehlbauer, J., 2022, Project F—Aquatic ecology and food base monitoring—

virtual presentation: Glen Canyon Dam Adaptive Management Program Adaptive 

Management Work Group Meeting, February 2022, Southwest Biological Science Center, 

Grand Canyon Monitoring and Research Center. 

Kennedy, T.A., Muehlbauer, J.D., Deemer, B.R., Yackulic, C.B., Ford, M.A., Szydlo, C., Metcalfe, 

A.N., and Lytle, D.A., 2022, Experimental Bug Flows increase algae production and insect 

diversity in the Colorado River, Grand Canyon—presentation: Joint Aquatic Sciences 

Meeting (JASM 2022), Grand Rapids, MI, May 2022.

Kennedy, T.A., Muehlbauer, J.D., Deemer, B.R., Yackulic, C.B., Ford, M.A., Szydlo, C., and 

Metcalfe, A.N., 2022, Experimental ‘Bug Flows’ increased algae production and insect 

diversity in the Colorado River, Grand Canyon: 16th Biennial Conference of Science and 

Management for the Colorado Plateau, Flagstaff, AZ, September 2022.

Freedman, J.W., Burke, M.K., Kennedy, T.A., and Lytle, D.A., 2022, Environmental DNA 

metabarcoding reveals aquatic invertebrate community diversity in the Grand Canyon—

presentation: Joint Aquatic Sciences Meeting (JASM 2022), Grand Rapids, MI, May 2022.

Metcalfe, A.N., Fritzinger, C.A., Kennedy, T.A., Dodrill, M.J., Muehlbauer, J.D., Holton, B., 

Durning, L.E., Sankey, J.B., and Weller, T., 2022, Bats, bugs, and boaters—Insectivorous bat 

foraging along the Colorado River in Grand Canyon is determined by the availability of 

aquatic flies: 16th Biennial Conference of Science and Management for the Colorado 

Plateau, Flagstaff, AZ, September 2022.

Metcalfe, A., Kennedy, T., Muehlbauer, J., Dodrill, M., Durning, L., Sankey, J., and Fritzinger C., 

2022, The role of insect abundance and riparian vegetation in driving bat foraging activity in 

Grand Canyon—Insights from a community science project—virtual presentation: Glen 

Canyon Dam Adaptive Management Program Annual Reporting Meeting, January 11-12, 

2022, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center. 

Metcalfe, A.N., Kennedy, T., Muehlbauer, J.D., Dodrill, M.J., Weller, T., Durning, L., Sankey, J.B., 

and C.A. Fritzinger, 2022, Insectivorous bat foraging along the Colorado River in Grand 

Canyon is determined by aquatic prey availability and tall vegetation density—presentation: 

Joint Aquatic Sciences Meeting (JASM 2022), Grand Rapids, MI, May 2022.

Muehlbauer, J., 2022, Bug Flows—Invertebrate response—virtual presentation: Science Advisor 

review of the Bug Flow Experiment, Day 1, October 2022. 
150

Traynham, L. and Kennedy, K., 2022, “Potential LTEMP experiments Spring/Summer 2022—

virtual presentation: Glen Canyon Dam Adaptive Management Program Technical Work 

Group Meeting, April 2022, Southwest Biological Science Center, Grand Canyon Monitoring 

and Research Center. 

Journal Articles:

Deemer, B.R., Yackulic, C.B., Hall, R.O., Jr., Dodrill, M.J., Kennedy, T.A., Muehlbauer, J.D.,

Topping, D.J., Voichick, N., and Yard, M.D., 2022, Experimental reductions in sub-daily flow 

fluctuations increased gross primary productivity for 425 river kilometers downstream: 

PNAS Nexus, v. 1, no. 3, pgac094, https://doi.org/10.1093/pnasnexus/pgac094. 

Kennedy, T.A., Metcalfe, A.N., Deemer, B.R., Ford, M.A., Szydlo, C.M., Yackulic, C.B., and 

Muehlbauer, J.D., 2022, Little bugs, big data, and Colorado River adaptive management—

Preliminary findings from the ongoing bug flow experiment at Glen Canyon Dam: Boatman's

Quarterly Review, v. 35, no. 3, p. 26-31. (Not available online)

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Metcalfe, A., Kennedy, T., Fritzinger, C., Dodrill, M.J., Szydlo, C.M., Muehlbauer, J.D., Yackulic, 

C.B., Holton, B.P., Durning, L.E., Sankey, J.B., and Weller, T.J., submitted, Insectivorous bat 

foraging tracks the availability of aquatic flies (Diptera): Journal of Wildlife Management. 

Project G Deliverables: Humpback Chub Population Dynamics throughout the 

Colorado River Ecosystem

Presentations:

Bair, L.S., 2022, Adaptive management and cultural ecosystem services—virtual presentation: 

ACES, A Community on Ecosystem Services Conference, December 2022.

Bair, L.S., 2022, Consideration of plural values in integrated assessments—presentation: AGU 

Chapman Conference, on ‘Solving Water Availability Challenges through an Interdisciplinary 

Framework’, September 12-16, 2022.

Dzul, M.C., and Yackulic, C.B., 2022, Effects of flow, sediment, and nonnative fishes on age-0 

population dynamics of humpback chub in the lower Little Colorado River—presentation: 

16th Biennial Conference of Science and Management for the Colorado Plateau and 

Southwest Region, September 12-15, 2022, Flagstaff, AZ.

Journal Articles:

Donovan, P., Reimer, M.N., Springborn, M.R., Yackulic, C.B., Bain, D.M., Bair. L.S., in prep, The 

economic cost of designer flows in river conservation. 

Dzul, M.C., Yackulic, C.B., Giardina, M., Yard, M., Van Haverbeke, D.R., in prep, Vital rates of a 

burgeoning population of humpback chub in western Grand Canyon.

Van Haverbeke, D.R., Dzul, M.C., Yackulic, C.B., Young, K.L., in prep, Abundance estimation of a 

recent prodigious humpback chub population in western Grand Canyon.
151

USFWS Reports:

Van Haverbeke, D.R., Young, K.L., Pillow, M.J., and Rinker, P.N., 2022, Mark-recapture and fish 

monitoring activities in the Little Colorado River in Grand Canyon from 2000 to 2021: 

Flagstaff, Ariz., U.S. Fish and Wildlife Service, submitted to U.S. Geological Survey Grand 

Canyon Monitoring and Research Center, 49 p. 

Van Haverbeke, D.R., K.L. Young, M.J. Pillow, and Rinker, P.N., 2022, Monitoring humpback 

chub in the Colorado River, Grand Canyon during fall 2021: Flagstaff, Ariz., U.S. Fish and 

Wildlife Service, USFWS Document no. USFWS-AZFWCO-22-04, 41 p.

Project H Deliverables: Salmonid Research and Monitoring

Journal Articles: 

Crossman, J.A., Webb, M.A.H., Korman, J., and Yard, M.D., 2022, Population reproductive 

structure of rainbow trout determined by histology and advancing methods to assign sex 

and assess spawning capability: Transactions of the American Fisheries Society, v. 151, no. 

4, p. 422-440, https://doi.org/10.1002/tafs.10356. 

Healy, B., Budy, P., Yackulic, C., Murphy, B.P., Schelly, R.C., and McKinstry, M.C., 2022, Exploring 

metapopulation-scale suppression alternatives for a global invader in a river network 

experiencing climate change: Conservation Biology, v. 37, no. 1, e13993, p. 1-18, 

https://doi.org/10.1111/cobi.13993. 

Healy, B.D., Yackulic, C.B., and Schelly, R.C., 2022, Impeding access to tributary spawning 

habitat and releasing experimental fall-timed floods increases brown trout immigration into 

a dam's tailwater: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0231. 

Korman, J., Deemer, B., Yackulic, C.B., Kennedy, T.A., and Giardina, M., 2022, Drought related 

changes in water quality surpass effects of experimental flows on trout growth downstream 

of Lake Powell reservoir: Canadian Journal of Fisheries and Aquatic Sciences, online, 

https://doi.org/10.1139/cjfas-2022-0142. 

Yard, M.D., Yackulic, C.B., Korman, J., Dodrill, M.J., and Deemer, B.R., 2023, Declines in prey 

production during the collapse of a tailwater rainbow trout population are associated with 

changing reservoir conditions: Transactions of the American Fisheries Society, v. 152, no. 1, 

p. 35-50, https://doi.org/10.1002/tafs.10381. 

USGS Reports: 

Giardina, M.A., Korman, J., Yard, M., Wright, S., Kaplinski, M., and Bennett, G., in final edits with 

the USGS Science Publishing Network, A literature review and hypsometric analysis to 

support decisions on trout management flows on the Colorado River downstream from 

Glen Canyon Dam: U.S. Geological Survey Open-File Report.

USGS Data Releases: 

Yackulic, C.B., Yard, M., Korman, J., Rogowski, D., Healy, B.D., Schelly, R.C., Omana-Smith, E., 

and Nelson, C., 2022, Brown trout movement data in Glen and Grand canyons, Arizona, 

USA: U.S. Geological Survey data release, https://doi.org/10.5066/P96NII4B. 
152

Project I Deliverables: Warm-Water Native and Nonnative Fish Research and 

Monitoring 

Presentations:

Frye, E., and Ward D., 2022, Common carp, uncommon predator—presentation: Desert Fishes 

Council 2022 Annual Meeting, November 16-18, 2022, Saint George, Utah.

Frye, E., and Ward D., 2022, Green sunfish, aquatic gremlins of the southwest—poster 

presentation: Desert Fishes Council 2022 Annual Meeting, November 16-18, 2022, Saint 

George, Utah.

Rogowski, R., 2022, Back to the future, warm-water fish in the Grand Canyon—presentation: 

Desert Fishes Council 2022 Annual Meeting, November 16-18, 2022, Saint George, Utah.

Ward D., and Frye, E., 2022, Oxygen manipulation for fisheries management—presentation: 

Desert Fishes Council 2022 Annual Meeting, November 16-18, 2022, Saint George, Utah.

Project J Deliverables: Socioeconomic Research in the Colorado River Ecosystem

Presentations:

Bair, L.S., and Bain, D.M., 2021, Identifying the total economic value of hydropower and 

implications for adaptive management of rivers—Operating restrictions of hydroelectric 

plants and their impacts on the operation of the Brazilian electric system—virtual 

presentation: XXIV Brazilian Symposium on Water Resources, November 2022.

Bair, L.S., 2021, Adaptive management and cultural ecosystem services—virtual presentation: 

ACES: A Community on Ecosystem Services conference, December 2022.

Bair, L.S. and Neher, C., 2022, Recreational anglers’ preferences for flow attributes—Taking 

advantage of a designer flow to validate novel scenarios—virtual presentation: The 

International Institute of Fisheries Economics and Trade, July 18-22, Vigo, Spain.

Bair, L.S., 2022, Consideration of plural values in integrated assessments—presentation: AGU 

Chapman Conference on Solving Water Availability Challenges through an Interdisciplinary 

Framework, September 12-16, Golden, Colorado. 

Journal Articles:

Donovan, P., Reimer, M.N., Springborn, M.R., Yackulic, C.B., Bain, D.M., Bair. L.S., in prep, The 

economic cost of designer flows in river conservation.

Hoelting, K., Morse, J.M., Gould, R., Martinez, D.E., Hauptfeld, R.S., Cravens, A.E., Breslow, S., 

Bair, L.S., Schuster, R.M., and Gavin, M.C., 2022, Opportunities for improved consideration 

of cultural benefits in environmental decision-making: SocArXiv, p. 1-42, 

https://doi.org/10.31235/osf.io/dpbe3. 

Jungers, B., Abbott, J.K., Bair, L.S., in prep: Program evaluation of the Lees Ferry brown trout 

incentivized harvest program. 
153

Project K Deliverables: Geospatial Science and Technology

Note: listed here are products that include Project K staff as authors; however, the work plan 

and budget for some products reside in other science projects.

Presentations:

Gushue, T.M., Andrews, C.M., and Thomas, J.E., 2022, Modernizing sensor data workflows to 

leverage Internet of Things (IoT) and cloud-based technologies—presentation: USGS 

Community for Data Integration monthly meeting, May 2022.

Gushue, T.M., Thomas, J.E., 2022, Modernizing sensor data workflows to leverage Internet of 

Things (IoT) and cloud-based technologies—presentation: USGS Cloud Hosting Solutions 

customer user group meeting, August 2022.

Gushue, T.M., Thomas, J.E., and Andrews, C.M., 2022, Modernizing data telemetry efforts for 

important riparian resources in the Grand Canyon—abstract for 16th Biennial Conference 

for Science and Management on the Colorado Plateau and Southwest Region, September 

12-15, 2022: Flagstaff, Ariz., U.S. Geological Survey, Southwest Biological Science Center, 

Grand Canyon Monitoring and Research Center, Flagstaff, Ariz. 

Thomas, J.E., Gushue, T.M., Andrews, C.M., and Unema, J., 2022, Using NWIS data from 

multiple gauging stations to capture event based video—presentation: USGS Community for 

Data Integration 2023 Request for Proposals Lightning Presentations.

Journal Articles:

Deemer, B.R., Andrews, C.M., Strock, K.E., Voichick, N., Hensleigh, J., Beaver, J.R., and Radtke, 

R., 2023, Over half a century record of limnology data from Lake Powell, desert southwest 

United States: From reservoir filling to present day (1964–2021): Limnology and 

Oceanography Letters, online, https://doi.org/10.1002/lol2.10310. 

USGS Reports:

Kaplinski, M., Hazel, J.E., Jr., Grams, P.E., Gushue, T.M., Buscombe, D., and Kohl, K., 2022, 

Channel mapping of the Colorado River from Glen Canyon Dam to Lees Ferry in Glen Canyon 

National Recreation Area, Arizona: U.S. Geological Survey Open-File Report 2022-1057, 20 

p., https://doi.org/10.3133/ofr20221057. 

USGS Data Releases:

Andrews, C.M., and Deemer, B.R., 2022, Limnology data from Lake Powell, desert southwest 

USA: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZIKVYW. 

Kaplinski, M., Hazel, J.E. Jr, Grams, P.E., Gushue, T.M., Buscombe, D.D., and Kohl, K., 2022, 

Channel mapping Glen Canyon Dam to Lees Ferry in Glen Canyon National Recreation Area, 

Arizona - Data: U.S. Geological Survey data release, https://doi.org/10.5066/P98GFP93. 

Manuals:

Thomas, J.E., 2022, Little Colorado River humpback chub Pit Tag master controller IoT system—

User and maintenance manual: Flagstaff, Ariz., U.S. Geological Survey, Southwest Biological

Science Center, Grand Canyon Monitoring and Research Center, SBSC-GCMRC-IoT Gitlab 

repository, https://code.usgs.gov/sbsc/sbsc-gcmrc-iot/little-colorado-river-mux-antenna/-
154

/blob/main/Little_Colorado_River_Pit_Tag_Master_Controller_Manual_V1.pdf. 

Thomas, J.E., 2022, Satellite remote relay design—User and maintenance manual, Flagstaff, 

Ariz., U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon

Monitoring and Research Center, SBSC-GCMRC-IoT Gitlab repository, 

https://code.usgs.gov/sbsc/sbsc-gcmrc-iot/iot-utilities/-

/blob/main/Satellite%20Relay%20System/Satellite_Remote_Reboot_Manual_V1.pdf. 

Thomas, J.E., 2022, Taylor Woods IoT Datalogger—User and maintenance manual: Flagstaff, 

Ariz., U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon

Monitoring and Research Center, SBSC-GCMRC-IoT Gitlab repository, 

https://code.usgs.gov/sbsc/sbsc-gcmrc-iot/taylor-woods-iot-data-loggers/-

/blob/main/Taylor_Woods_IoT_Datalogger_Manual_V2.pdf. 

Websites & Web Applications:

• Updated Sandbar Monitoring Data website: https://www.usgs.gov/apps/sandbar/

• Sandbar Monitoring Photo Viewer: 

https://grandcanyon.usgs.gov/gisapps/sandbarphotoviewer/RemoteCameraTimeSeries.

html

• Adopt-A-Beach Sites Photo Viewer: https://grandcanyon.usgs.gov/gisapps/adopt-abeach/index.html

• Grand Canyon Geospatial Portal: 

https://grandcanyon.usgs.gov/portal/home/index.html

• Geospatial Services page (for advanced GIS users and developers):

https://grandcanyon.usgs.gov/gisapps/restservices/index_wret.html

Web Content on ESRI ArcGIS Online: 

• Predicted Shorelines for High Flows on the Colorado River Application:

https://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=721001c63d9145888

3340f05c68c55f4 

• River Campsite Web Application: 

https://usgs.maps.arcgis.com/home/item.html?id=0f9f6575bfee406cac6593b29388366

5

• Access to Geospatial Data Holdings – ESRI’s ArcGIS Online (note: some content not

shared to the public): 

http://usgs.maps.arcgis.com/home/search.html?q=GCMRC&t=content

Online Data Visualizations: 

Gushue, T.M, and Thomas, J.E., 2021, Daily Water-Quality Data at Glen Canyon Dam—online 

data visualization: Flagstaff, Ariz., U.S. Geological Survey, Southwest Biological Science

Center, Grand Canyon Monitoring and Research Center,

https://tableau.usgs.gov/t/InternalGuestAccess/views/WaterQualityatGlenCanyonDam/Dail

yWaterQualityDataatGlenCanyonDam?%3Aembed=y&%3AisGuestRedirectFromVizportal=y

#1. 
155

Hensleigh, J., Andrews, C.M., Voichick, N., and Deemer, B., 2022, Lake Powell vertical waterquality profiles—online data visualization: Flagstaff, Ariz., U.S. Geological Survey, Southwest 

Biological Science Center, Grand Canyon Monitoring and Research Center,

https://tableau.usgs.gov/views/view-profiles-by-station-collectiondate/ProfileByStationVisitDateDashboard.

Project N Deliverables: Hydropower Monitoring and Research

Presentations:

Bair, L.S., and Bain, D.M., 2021, Identifying the total economic value of hydropower and 

implications for adaptive management of rivers—Operating restrictions of hydroelectric 

plants and their impacts on the operation of the Brazilian electric system—virtual 

presentation: XXIV Brazilian Symposium on Water Resources, November 2021.

Journal Articles:

Donovan, P., Reimer, M.N., Springborn, M.R., Yackulic, C.B., Bain, D.M., Bair. L.S., in prep, The 

economic cost of designer flows in river conservation.

Project O Deliverables: Is Timing Really Everything? Evaluating Resource Response 

to Spring Disturbance Flows 

Presentations:

Bair, L.S. and Neher, C., 2022, Recreational anglers’ preferences for flow attributes—Taking 

advantage of a designer flow to validate novel scenarios—virtual presentation: The 

International Institute of Fisheries Economics & Trade, Vigo, Spain, July 18-22, 2022.

Kennedy, T., Deemer, B., Lytle, D., Grams, P., Sankey, J., Butterfield, B., Dibble, K., Tusso, R., and 

Bair, L., 2022, Spring disturbance flow update—virtual presentation: Glen Canyon Dam 

Adaptive Management Program Annual Reporting Meeting, January 2022. 

Kennedy, T., Deemer, B., Lytle, D., Grams, P., Sankey, J., Butterfield, B., Dibble, K., Tusso, R., and 

Bair, L., 2022, Spring disturbance flow update—virtual presentation: Glen Canyon Dam 

Adaptive Management Program Adaptive Management Work Group Meeting, February 

2022.

Kurthen, A.L, Lytle, D.A., and Kennedy, T.A., 2022, Developing a mechanistic modeling 

framework for aquatic invertebrate communities in dammed rivers: Joint Aquatic Sciences 

Meeting (JASM 2022), Grand Rapids, MI, May 2022. 

Journal Articles:

Butterfield, B.J. and Palmquist, E.C., in review, Divergent physiological responses of hydric and 

mesic riparian plant species to a Colorado River experimental flow: Plant Ecology.

Sankey, J.B., Caster, J., Kasprak, A., and Fairley, H., 2022, The influence of drying on the aeolian 

transport of river-sourced sand: JGR Earth Surface, v. 127, no. 12, e2022JF006816, p. 1-24, 

https://doi.org/10.1029/2022JF006816.
156

Appendix 3: Budgets, All Projects

Project A Budget

Project B Budget

Burden

12.326%

Budgeted

Amount $485,907 $10,000 $58,500 $0 $392,587 $68,336 $1,015,330 

Actual

Spent $497,227 $2,431 $83,030 $0 $459,407 $71,822 $1,113,917 

(Over)/Under

Budget ($11,320) $7,569 ($24,530) $0 ($66,820) ($3,486) ($98,587)

FY21 Unspent Funds $135,000 FY22 Unspent Funds $36,413

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated unspent funds; etc.)

FY22 Comments:

-Overspent Salaries during FY22 is due to shortfall in the budget for essential project staff.

-Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

-Overspent Operating Expenses was for instrument repairs and replacements initiated in Q4 FY22 that will be completed in 

FY23.

-Overspending To other USGS Centers is due to rising costs for database/website design at Fort Collins and and EROS Scienece 

centers.

Project A Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers

Burden

12.326%

Budgeted

Amount $382,144 $5,000 $32,000 $353,293 $0 $62,262 $834,699 

Actual

Spent $436,289 $7,555 $48,891 $8,000 $0 $60,974 $561,709 

(Over)/Under

Budget ($54,145) ($2,555) ($16,891) $345,293 $0 $1,288 $272,990 

FY21 Unspent Funds $0 FY22 Unspent Funds $272,990

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated unspent; etc.)

FY22 Comments:

-Overspent Salaries is due to bringing staff from other USGS centers and overtime associated with the Channel Mapping river 

trip that was rescheduled from FY21.

-Overspent Travel & Training is due to field work and the Channel Mapping river trip that was moved from FY21 to FY22 due to 

Covid-19.

-Overspent Operating Expenses is due to necessary Inertial Navigation System equipment rental for the Channel Mapping river 

trip. 

-Underspent funds in Cooperative Agreements is due to personnel working on this project left Northern Arizona University and 

the agreement will not be continued. The work will be accomplished by increasing staff at GCMRC. 

Project B Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
157

Project C Budget

Project D Budget

Burden

12.326%

Budgeted

Amount $134,307 $3,940 $1,565 $107,337 $0 $20,453 $267,602 

Actual

Spent $133,693 $2,129 $1,102 $109,097 $0 $20,150 $266,170 

(Over)/Under

Budget $614 $1,811 $464 ($1,760) $0 $303 $1,432 

FY21 Unspent Funds $0 FY22 Unspent Funds $1,432

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated unspent; etc.)

FY22 Comments:

-Underspent Salaries is due to technician turnover on this project.

-Underspent Travel & Training were to compensate for increased botanist costs. A local conference was attended instead of a 

national conference.

-Overspent funds in Cooperative Agreements was due to increased costs for hiring botanists through NPS.

Project C Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers

Burden

12.326%

Budgeted

Amount $214,084 $10,600 $2,806 $0 $0 $28,040 $255,530 

Actual

Spent $208,980 $4,351 $14,417 $0 $0 $28,072 $255,820 

(Over)/Under

Budget $5,104 $6,249 ($11,611) $0 $0 ($32) ($290)

FY21 Unspent Funds $0 FY22 Unspent Funds ($290)

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

- Underspent Salaries is due to staff turnover at the end of the FY.

- Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Overspent amount in Operating Expenses was to cover required instrument calibration. 

Project D Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
158

Project E Budget

Project F Budget

Burden

12.326%

Budgeted

Amount $200,851 $10,500 $17,272 $14,500 $0 $28,615 $271,738 

Actual

Spent $178,114 $3,893 $21,314 $5,000 $0 $25,211 $233,532 

(Over)/Under

Budget $22,737 $6,607 ($4,042) $9,500 $0 $3,404 $38,206 

FY21 Unspent Funds $0 FY22 Unspent Funds $38,206

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Underspent Salaries is due to HR-delays in hiring and staff turnover.

- Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Overspent in Operating Expenses is for purchases of necessary lab equipment.

- Underspent funds in Cooperative Agreements is due to funds obligated in FY22 that will be expended in FY23. 

Project E Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers

Burden

12.326%

Budgeted

Amount $503,666 $15,283 $37,810 $0 $0 $68,626 $625,385 

Actual

Spent $537,820 $13,728 $42,304 $0 $0 $73,198 $667,051 

(Over)/Under

Budget ($34,154) $1,555 ($4,494) $0 $0 ($4,572) ($41,666)

FY21 Unspent Funds $17,816 FY22 Unspent Funds ($23,850)

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Overspent Salaries is due to promotions among staff and overtime associated with Bug Flow field studies and fall seining trip.

- Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Overspent in Operating Expenses is for payments to community science participants and purchase of additional drift sampling 

equipment needed to provide JCM trips with their own gear for collection on trips.

Project F Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
159

Project G Budget

Project H Budget

Burden

12.326%

Budgeted

Amount $343,451 $4,000 $79,500 $520,766 $0 $68,249 $1,015,966 

Actual

Spent $316,378 $1,731 $75,153 $520,766 $0 $64,097 $978,126 

(Over)/Under

Budget $27,073 $2,269 $4,347 $0 $0 $4,152 $37,840 

FY21 Unspent Funds $0 FY22 Unspent Funds $37,840

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

- Underspent Salaries is due to HR-delays in filling positions and staff turnover. 

- Underspent Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Underspent in Operating Expenses due to Pit Tags being purchased through BOR instead of the project.

Project G Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers

Burden

12.326%

Budgeted

Amount $181,222 $11,700 $25,566 $148,000 $0 $31,371 $397,859 

Actual

Spent $123,423 $5,874 $68,077 $152,685 $0 $28,909 $378,968 

(Over)/Under

Budget $57,799 $5,826 ($42,511) ($4,685) $0 $2,462 $18,891 

FY21 Unspent Funds $0 FY22 Unspent Funds $18,891

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

-Underspent Salaries is due to HR-delays in filling positions and staff turnover. 

- Underspent in Travel & Training is due to Covid 19 impacts that limited or cancelled in person conferences.

- Overspent in Operating Expenses is due to change in funding mechanism for a cooperator from a Cooperative Agreement to a 

contract. 

-Overspent amount in Cooperative Agreement is additional funds sent to USFWS for eDNA analysis. 

Project H Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers
160

Project I Budget

Project J Budget

Burden

12.326%

Budgeted

Amount $233,790 $0 $12,100 $273,110 $0 $38,502 $557,502 

Actual

Spent $272,402 $1,724 $18,141 $273,110 $0 $44,218 $609,595 

(Over)/Under

Budget ($38,612) ($1,724) ($6,041) $0 $0 ($5,716) ($52,093)

FY21 Unspent Funds $0 FY22 Unspent Funds ($52,093)

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

-Overspent Salaries is due to assignment of project staff reassigned back to the project to ensure completion of all project tasks 

outlined in the workplan. 

-Overspent funds in travel and training is due to travel and training completed in FY22 that was rescheduled from FY21.

-Overspent funds in Operating Expenses is for purchases of necessary lab equipment and field supplies.

Project I Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total

Burden

12.326%

Budgeted

Amount $124,588 $3,000 $1,500 $45,500 $0 $17,276 $191,864 

Actual

Spent $95,952 $5,874 $9,782 $69,000 $0 $15,827 $196,435 

(Over)/Under

Budget $28,636 ($2,874) ($8,282) ($23,500) $0 $1,449 ($4,571)

FY21 Unspent Funds $0 FY22 Unspent Funds ($4,571)

To other

USGS Centers Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

- Underspent Salaries is due to change in mechanism for completing work with cooperators and contractors instead of salaried 

employees. 

- Overspent Travel & Training is due to an international workshop organized by The Amazon Dams Network in Brazil.

- Overspent funds in Cooperative Agreement is due to change in mechanism for completing work with cooperators and 

contractors.

Project J Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements
161

Project K Budget

Project L Budget

Burden

12.326%

Budgeted

Amount $372,175 $4,970 $3,400 $0 $0 $46,906 $427,451 

Actual

Spent $275,035 $0 $11,342 $0 $0 $35,299 $321,676 

(Over)/Under

Budget $97,140 $4,970 ($7,942) $0 $0 $11,607 $105,775 

FY21 Unspent Funds $0 FY22 Unspent Funds $105,775

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

- Unspent Salaries is due to staff turnover in FY22 and HR-delays in hiring of a Database Administrator and a Geographer which 

will occur in FY23. 

- Unspent Travel & Training money due to travel restrictions imposed by COVID-19 pandemic.

-Overspent funds in Operating Expenses is for purchases of necessary information technology hardware and equipment for 

remote data collection and transmission.

Project K Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total

Burden

12.326%

Budgeted

Amount $164,641 $0 $0 $80,596 $0 $22,712 $267,949 

Actual

Spent $153,144 $2,286 $11,482 $80,596 $0 $22,992 $270,501 

(Over)/Under

Budget $11,497 ($2,286) ($11,482) $0 $0 ($280) ($2,552)

FY21 Unspent Funds $0 FY22 Unspent Funds ($2,552)

To other

USGS Centers Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

-Underspent Salaries is due to staff turnover at the end of the fiscal year and change in mechanism for completing work.

-Overspent Travel & Training was for travel for a cooperator to the bi-ennial conference. 

-Overspent in Operating Expenses is due to compensating contractors for data analysis.

Project L Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements
162

Project M Budget

Logistics Budget

Burden

12.326%

Budgeted

Amount $690,221 $20,000 $178,000 $0 $0 $109,482 $997,703 

Actual

Spent $535,988 $0 $194,321 $0 $0 $90,018 $820,327 

(Over)/Under

Budget $154,233 $20,000 ($16,321) $0 $0 $19,464 $177,376 

FY21 Unspent Funds $0 FY22 Unspent Funds $177,376

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Underspent Salaries is due to staff turnover and HR delays in hiring the new GCMRC Chief.

- Underspent Travel & Training was due to travel restrictions and cancellations associated with COVID-19.

- Overspent funds in Operating Expenses is due to providing funds for shortfalls for project A and rising costs for vehicle 

maintenance and fuel.

Project M Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total

Burden

12.326%

Budgeted

Amount $269,502 $3,000 $1,074,767 $11,000 $0 $166,394 $1,524,663 

Actual

Spent $216,046 $102 $1,237,597 $18,000 $0 $179,729 $1,651,474 

(Over)/Under

Budget $53,456 $2,898 ($162,830) ($7,000) $0 ($13,335) ($126,811)

FY21 Unspent Funds $131,070 FY22 Unspent Funds $4,259

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Underspent Salaries is due to change in staff and crediting warehouse staff hours for tribal and stakeholder river trips.

- Underspent funds for Travel & Training were due to travel restrictions associated with COVID-19.

- Overspent funds in Operating Expenses is due to the rescheduled Channel Mapping river trip from project B from FY21 that 

was completed in FY22. 

- Overspent funds in Cooperative Agreements is due to the Grand Canyon Youth cooperative agreement adding an annual trip 

for tribal youth.

Logistics Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total
163

Project N Budget

Project O Budget

Burden

12.326%

Budgeted

Amount $16,180 $1,500 $2,500 $0 $0 $2,487 $22,667 

Actual

Spent $18,314 $0 $0 $0 $0 $2,257 $20,571 

(Over)/Under

Budget ($2,134) $1,500 $2,500 $0 $0 $230 $2,096 

FY21 Unspent Funds $0 FY22 Unspent Funds $2,096

To other

USGS Centers Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments: 

-Overspending Salaries is due to higher employee salary costs.

-Underspent Travel & Training is due to cancellations assocaited with COVID-19.

-Underspent funds in Operating Expenses was for software that was provided by USGS licensing at no cost to the project. 

Project N Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

Burden

12.326%

Budgeted

Amount $230,993 $12,000 $5,000 $25,885 $40,667 $31,344 $345,889 

Actual

Spent $50,443 $1,411 $25,047 $168,500 $0 $14,534 $259,935 

(Over)/Under

Budget $180,550 $10,589 ($20,047) ($142,615) $40,667 $16,810 $85,954 

FY21 Unspent Funds $0 FY22 Unspent Funds $85,954

Project O Salaries Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers

Total

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Project O is entirely funded through FY21 unspent funds.

- Underspent Salaries were covered by USGS employees as well as through CESU cooperative agreements with Oregan State 

University and Utah State University.

-Overspent Operating Expenses is a contract with Marda Science for Riverbed Vegetation mapping awarded in FY22 instead of 

FY21.

-Overspent amount in Cooperative Agreement is due to change in mechanism for completing work through CESU cooperative 

agreements.
164

Budget Summary – Adaptive Management Program Total (without Lake Powell 

Agreement and without Project O) 

Appendix 1 Budget

Burden

12.326%

Budgeted

Amount $4,316,729 $103,493 $1,527,286 $1,554,102 $392,587 $779,713 $8,673,910 

Actual

Spent $3,998,805 $51,678 $1,836,953 $1,236,254 $459,407 $762,773 $8,345,871 

(Over)/Under

Budget $317,924 $51,815 ($309,667) $317,848 ($66,820) $16,940 $328,039 

FY21 Unspent Funds $0 FY22 Unspent Funds $611,924

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- Actual unspent total balance will be used to cover planned budget shortfalls and unfunded work in FY23 and FY24.

Budget Summary Adaptive Management Program Total (without Lake Powell agreement)

Total Salaries

Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers Total

Burden

20.163%

Budgeted

Amount $145,065 $8,814 $11,968 $0 $0 $33,440 $199,287 

Actual

Spent $188,290 $5,699 $24,507 $0 $0 $44,055 $262,551 

(Over)/Under

Budget ($43,225) $3,115 ($12,539) $0 $0 ($10,615) ($63,264)

 Unspent Funds $63,264 2022 Unspent Funds $0

COMMENTS (Discuss anomalies in the budget; expected changes; anticipated carryover; etc.)

FY22 Comments:

- This project is funded entirely by Reclamation with non-GCDAMP funding.

- This agreeemnt period of performance ended 12/31/2022 and shows all funding expended through the calendar year. 

- Overspent Salaries is due to this agreement being on the calendar year rather than the fiscal year and actual salary 

overspending is between 9/30/22 and 12/31/2022 when the agreement ended. 

- Underspent Travel & Training were due to travel restrictions associated with COVID-19.

-Overspent Operating Expenses is for a Sonde and equipment purchase that was made after the fiscal year. 

-All funds have been expended at the end of the calendar year and a new 5 year agreeement start date is 1/1/2023-12/31/2027

Lake Powell (NOT GCDAMP funded)

Salaries Travel & 

Training

Operating 

Expenses

Cooperative 

Agreements

To other

USGS Centers

Total