Assessing 50 years of ecological 

changes at campsites along the 

Colorado River in Grand Canyon

H.C. Fairley1, M.L. Scott2 and A.H. Fairley1

Annual Reporting Meeting, January 25, 2023

This information is preliminary and subject to revision. It is being provided to meet the need for timely science.

This information is provided on the condition that neither the US. Geological Survey nor the U.S. Government shall be

held liable for any damages resulting from the authorized or unauthorized use of this information. 

1 US Geological Survey, Southwest Biological Science 

Center, Grand Canyon Monitoring and Research Center

2Colorado State University
Project Background

• Project D, Element 2: Monitoring Landscape-Scale Ecological Change 

with Repeat Photography

• Use repeat photography methods and analysis of matched images to 

document changes in riparian cover throughout the Colorado River 

ecosystem in Glen and Grand Canyon to refine current understanding of 

how vegetation growth and expansion has evolved and affected 

availability of open sand/aeolian sand sources.

• FY2022 Budget: $35,654 ($23k salary, plus travel, ops, burden)

• Initial photo matching focused on images from the 1923 Birdseye 

Expedition (pre-dam condition)

• More recently (2021-2022) we have focused on matching photographs 

from the 1973 Borden-Weeden campsite inventory (showing early postdam condition, ~10 years after dam construction)
Summary

• ~240 photos from 1973; 

122 matched so far; 

108 analyzed here

• we precisely match the 

historical views

• photo matches provide 

unambiguous record of 

change over time

• document & categorize 

geomorphic and 

vegetation changes

• summarize categorical 

assessments [after 

R.H.Webb (1990)] 

Above North Canyon, 1973
Main Objectives

Evaluate broad-scale changes in: 

1) sand supply and exposure

2) vegetation cover

3) dominant vegetation composition

• Evaluate connectivity between river 

sediments and terrestrial ecosystems

• Document on-going vegetation 

responses to flow management

Preliminary Results – subject to revision. Not for distribution or citation.
Sand deflation

RM 20.2L

Original photo July 1973

Matched by A.H. Fairley 4/29 /2022

Preliminary Results – subject to revision. Not for distribution or citation.
RM 150.3R

Original photo July 1973

Matched by A.H. Fairley 5/18/2021

Preliminary Results – subject to revision. Not for distribution or citation.
Examples: Beach Front Erosion

RM 19.4L, top: original photo, July 1973

Bottom: match by A.H Fairley, 4/29/22 

RM 31.9R, top: original photo, July 1973

Bottom: match by A.H Fairley, 4/29/22 
Examples of Deflation

RM 44.1L, top photo: July 1973

Bottom photo: A.H Fairley, 5/8/21 

RM 37.9L, top photo: July 1973

Bottom photo: Camille Diab, 5/1/22 
Examples: Surface Deflation

RM 114.9R, top: original photo, July 1973

Bottom: match by A.H Fairley, 5/8/22 

RM 115.1R, top: original photo, July 1973

Bottom: match by A.H Fairley, 5/8/22 
Both inflation and deflation may be evident

RM 124.2L. Top photo: July 1973

Bottom photo: A.H Fairley, 5/11/22 

RM 133.7L. Top photo: July 1973

Bottom photo: A.H Fairley, 5/8/22 
More examples of inflation/deflation

RM 26.9L, Top photo: July 1973

Bottom photo: A.H Fairley, 5/7/21 

RM 119.5L. Top photo: July 1973

Bottom photo: A.H Fairley, 5/15/21
Preliminary Results

• Shoreline erosion/bank steepening at 

>50% sites

• Sand deflation at 56% of sites examined

• Sand inflation at 37% of sites examined

• Sand surfaces generally less active due 

to reduction in sand deposition, soil 

crust development, vegetation increase 

Preliminary Results – subject to revision. Not for distribution or citation.
Preliminary Results – subject to revision. Not for distribution or citation.

RM 219, RB, original photo July 1973

Photo match by A.H. Fairley, 05/21/2021
Vegetation encroachment is prevalent.

Density varies by substrate and use 

Examples of two popular camps with light vegetation encroachment

Nautiloid, RM 35.1L. Top: July 1973; 

Bottom photo: A.H. Fairley 5/1/22

Lower Fossil, RM 126.1L. Top: July 1973; 

Bottom photo: A.H. Fairley 5/1/22
Examples of camps with medium 

vegetation encroachment

RM 136.8L. Top photo: July 1973

Bottom photo: A.H. Fairley, 5/12/22 

RM 37.7R. Top photo: July 1973

Bottom photo: A.H Fairley, 5/1/22 
Examples of heavy vegetation encroachment

RM 170.5L. Top photo: July 1973

Bottom photo: A.H Fairley, 5/12/22 

RM 122.9L. Top photo: July 1973

Bottom photo: A.H Fairley, 5/10/22 
Results

• Vegetation cover > at 98% of sites

• Density of total cover varied Percentage of sites (%)

Density of cover

Preliminary Results – subject to revision. Not for distribution or citation.
More Results

Medium to dense 

nearshore

vegetation cover 

present 

at 92% of sites

Photograph by M. Scott, May 15, 2019

Preliminary Results – subject to revision. Not for distribution or citation.
Nearshore vegetation encroachment 

contributes to bank steepening/retreat

RM 199.2L, Top photo: E.C. LaRue 9/18/1923 

Bottom photo: A.H. Fairley, 5/19/2021 

Zone 1* vegetation

Photograph by M. Scott, April 30, 2018

• discharge range: 226-708 m3/s (8,000-25,000 cfs)

(post-dam modified low fluctuating flow regime)

• obligate riparian shrubs

(Baccharis spp, Salix exigua, Pluchea sericea)

• + herbaceous species are armoring banks

* Defined by Sankey et al 2015 

Preliminary Results – subject to revision. Not for distribution or citation.
ANOSIM: R=0.494, p=0.01

Species presence

Results: Zone 1 NMDS ordination, Bray-Curtis dissimilarity

Preliminary Results – subject to revision. Not for distribution or citation.
Results: Zone 1

• Out of 139 species, 26 unique to Zone 1 

• 6 of 10 most abundant species: 

non-natives

• 6 of 10 most abundant species: facultative 

or obligate wetland species 

• Species of note....

Preliminary Results – subject to revision. No for distribution or citation.
Schedonorus arundinaceus (tall fescue)

• Present at 80% of 

sites

• Robust, non-native 

perennial; invasive

• Participating in bank 

armoring

• Similar to other flowregulated rivers

Preliminary Results – subject to revision. Not for distribution or citation.

Photograph from https://soilcropandmore.info/crops/Grasses/Tall_fescue/086.jpg.
Conclusions

• Sand deflation at 56% of sites examined

• Sand inflation at 37% of sites examined

• Shoreline erosion/steepening at >50% sites

• Sand flux variable across sites

• Vegetation cover ↑ at 98% of sites

• Zone 1 vegetation present at 92% of sites

• Compositionally distinct (exotic & wetland)

• Tall, rhizomatous, perennial herbs favored 

by reduced flow variability

Preliminary Results – subject to revision. Not for distribution or citation.
Future Steps

• Complete matching the remaining 1973 photos

• Further analysis of categorical ecological changes

• Link 1973 campsites to bar types per Mueller et al. 2018

• Use 1973 photos to “ground truth” open sand area in 1973 aerial images

• Publish 1923 and 1973 matched images with 

interpretation of ecological changes

• Serve matched images via GCMRC website

•Match additional photo sets:

• 1940 Goldwater photos

• 1963 Low Water photos
Many thanks to our dedicated volunteers!

Questions?