Channel Response to High Flows

in Western Grand Canyon 

GCDAMP Annual Reporting Meeting 

January 24, 2024 

Matt Kaplinski 

U.S. Geological Survey 

Southwest Biological Science Center 

Grand Canyon Monitoring and Research Center 
 

 

 

Acknowledgments 

• This project is funded by the GCDAMP with additional support from 

BOR/USGS 

• Paul Grams, Shannon Sartain, Keith Kohl, Katie Chapman, Vincent 

Diaz, Erica Byerley, Tom Gushue, Robert Tusso 

• Corey Sannes: U.S. Geological Survey, Arizona Water Science Center 

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

Logistics Staff 

• Thanks to the Hualapai tribe and National Park Service for their support, 

cooperation, and shared interest in the sediment dynamics of the 

western Grand Canyon 
 

 

Outline 

• Objectives 

• Background - Western Grand Canyon Geomorphology 

• Study reach 

• Data Collection – Field Surveys 

• Results 

• Changes to the bed 

• Changes to the bank 

• Conclusions/Future work/Recommendations 
 

 

Objective: Understand and quantify relation between 

changes in bed configuration in Western Grand Canyon 

and dam releases. 

Do certain dam operations reduce, exacerbate or mitigate 

sediment accumulation in this reach? 
 

Glen Canyon Overview of Western Grand Canyon 

Geomorphology 

Grand Canyon 

Western 

Grand Canyon 
 

Glen Canyon Overview of Western Grand Canyon 

Geomorphology 

Grand Canyon 

Western 

Grand Canyon 
280 

260 

200 

270 

Study Reach 

210 

250 

220 240 

Spencer Creek 

(Lava Cliff Rapid) 230 

Diamond Creek 
Grand Canyon Western Grand Canyon 

Diamond Creek 

Spencer Canyon 

(Lava Cliff Rapid) Study Reach 

(RMs 273.0 to 275.5) 

Surprise Canyon 
 

Diamond Creek 

Spencer Canyon 

(Lava Cliff Rapid) 

Surprise Canyon 

Study Reach 

(RMs 273.0 to 275.5) 

Grand Canyon Western Grand Canyon 
280 

260 

200 

270 

210 

Study Reach 

250 

220 240 

Spencer Creek 

(Lava Cliff Rapid) 230 

Diamond Creek 
Pearce Ferry 

Boat Ramp 

Pearce Ferry 

Rapids 

Study Reach 
 

 

GCMRC Control Network Benchmark 

Temporary Streamflow Gage 

GCMRC River Miles 

275 

274 

273 

Flow 
Dates of Field Surveys 

Spring Disturbance Flow (SDF) HFE 

Date 

Discharge at Colorado Rivernear Diamond Creek (cfs) 

 
 

 

Temporary Gage at RM 275 

• This gage measures water surface elevation 

• It is used to calculate travel time between the Colorado River 

gage at Diamond Creek (RM 226) and the study reach 

Preliminary results, subject to review, do not cite 
Field Surveys: Data Collected 

• GPS observations of benchmarks 

• Multibeam sonar survey of riverbed 

• Boat-based lidar survey of banks 

• Ground-based RTK-GPS survey of water’s edge, topography, and 

check points 

• Time-lapse cameras to show bars during low-flow and bank erosion 

RTK-GPS collection 

of water’s edge 

 

 

 

 

 Multibeam sonar survey display showing live soundings of the bed 

GPS receivers, Multibeam 

sonar, and LiDAR mounted to 

boat 

GPS receiver on 

benchmark 
275 

274 

273 

Flow 

Dune fields 

Scour holes 

Results: Median riverbed elevation 
Median bed elevation 

 

Bed elevations in dune fields (straight reaches) 

variable but not changing systematically 

Scour during SDF and 

HFE in “holes” at bends 

Preliminary results, subject to review, do not cite 
 

 

Changes in the Riverbed 

• Scour in scour holes

• No change to slight

deposition or slight

erosion in dune fields

Bed elevation changes from 4/25 to 

5/12/2023 (pre-HFE to post-HFE) 

Preliminary results, subject to review, do not cite 
Changes in the Riverbed by Sub-reach 

Preliminary results, subject to review, do not cite 

Dune field 

Dune field 

Scour hole 
 

 

Changes in the Riverbed by Sub-reach 

Dune fields 

• No systematic change in bed 

elevation as function of 

discharge. 

• Max, min and mean bed 

elevations are similar pre- and 

post-SDF or HFE 

Scour holes 

• Scour with increasing 

discharge (fill back in when 

discharge drops) 

Preliminary results, subject to review, do not cite 
Results: Changes in the Riverbanks 

Cross Sections 
Bank retreat in the 10’s 

of meters over 2 years 

Majority of bank 

erosion NOT 

associated with high 

flows & occurred 

between 2021 and 

2023 surveys 

Preliminary results, subject to review, do not cite 

 

 

 

 

 

 
River is getting wider, 

but not incising 

vertically – at least 

between 2021 & 2023 

Preliminary results, subject to review, do not cite 

 

 
 

 

 

 

 

 

Conclusions 

• The bed in the reach is dynamic 

– 2 to 3 m of scour and fill in scour holes during high flows 

(SDF and HFE) 

– ~ 0.5 m of bed variability in dune fields across all flows 

– Slight aggradation of dunes during high flows, but followed 

by slight erosion after high flows 

– No systematic correlation between bar heights and 

discharge. 

• Mean condition of the channel is relatively stable 

– Likely controlled by downstream Pearce Ferry Rapid 

• Banks are eroding 
 

 

 

 

 

 

Future Work and Recommendations 

• Complete analysis of changes in Columbine study reach. 

Error analysis 

Segment volume/area change 

• Complete analysis of bedload sediment transport 

Repeat surveys 

• Develop Stage Discharge relationship in study reach 

• Develop sediment budget for Western Grand Canyon based on transport measurements (CR

at Diamond Creek) and estimates of sediment input from banks. 

• Develop and calibrate numerical flow model for study reach. 

• Use model to predict response to different dam operations. 

• Permanent install of streamflow gage? (currently funded through FY 2024) 
Thank You 

Questions? 

Matt Kaplinski - mkaplinski@usgs.gov 

Paul Grams - pgrams@usgs.gov 
 

Columbine Reach Bank erosion 

• Time-lapse 

cameras capture 

bank erosion 

• This bank eroded 

on July 14 and 15, 

2021