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Abstract

Longitudinal profiles of water surface and riverbed elevations capture key geomorphic characteristics that can be affected by water infrastructure and natural processes. Continuous water surface profiles of the Colorado River in Grand Canyon, a river influenced by two of the largest dams in the United States, have been measured infrequently. The water surface profile was first measured in 1923, 13 years before the completion of Hoover Dam, which impounded water into western Grand Canyon, and 40 years before the completion of Glen Canyon Dam, which affected streamflow and sediment supply for all of Grand Canyon. The water surface profile was next measured in 2000, 37 years after the completion of Glen Canyon Dam, although this profile did not include the segment affected by Hoover Dam. A continuous profile of riverbed elevations has never been published. Here, we present the first complete, coupled water surface and riverbed elevation profiles, collected in 2021 during a period of steady releases from Glen Canyon Dam. The profiles were constructed from positions and elevations measured by boat-based global navigation satellite systems and from bathymetry collected by multibeam sonar. Data collected by boat were supplemented by data from a photogrammetry-derived digital surface model that was created from concurrently collected aerial images. Independent measurements made by conventional total stations referenced to a common geodetic control network were used to evaluate accuracy of all measurements. The final water surface and riverbed elevation profiles improved the accuracy and precision reported for previous profiles. In this study, the mean absolute vertical accuracy of water surface elevations was 0.07 meter for 85 percent of river miles and 0.19 meter for 11 percent of river miles. For the remaining 4 percent of river miles, water surface elevations were interpolated between measured values. The profiles reported herein can be used for current assessment of Colorado River geomorphic conditions, quantification of changes in the river over time, and predictive modeling of river resources for potential future management scenarios.quantification of changes in the river over time, and predictive modeling of river resources for potential future management scenarios.

Plain Language Summary

We measured the elevation of 282 miles of the water surface and riverbed of the Colorado River in Grand Canyon, from Lees Ferry, Arizona, to Pearce Ferry, Ariz. We collected water surface and riverbed elevations during a period of steady releases from Glen Canyon Dam in 2021. We used multiple, concurrent methods to measure the elevation of the water surface and assessed error for each measurement method to use the most accurate data possible in the final elevation profile. The final water surface profile is measured to the centimeter every river hundredth mile, with vertical uncertainty less than or equal to 0.07 meter for 85 percent of the river and less than or equal to 0.19 meter for the remainder of the river. We collected bathymetry of the river centerline everywhere possible, which did not include rapids and shallow areas. This study is the third measurement of a complete water surface profile; the first was collected in 1923, 40 years before Glen Canyon Dam was completed, and the second was collected in 2000, 37 years after Glen Canyon Dam was completed. A continuous riverbed profile had not been collected previously.

Suggested Citation

Sartain, S.L., Kaplinski, M.A., Kohl, K., Chapman, K.A., Bransky, N.D., Sankey, J.B., and Grams, P.E., 2026, Continuous and high-resolution longitudinal profiles of the water surface and riverbed elevation for 282 miles of the Colorado River from Lees Ferry to Pearce Ferry, Arizona, 2021: U.S. Geological Survey Scientific Investigations Report 2026–5010, 40 p., https://doi.org/10.3133/sir20265010.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Plain Language Summary
  • Introduction
  • Data Collection
  • Data Processing and Accuracy Analysis
  • Results
  • Conclusions
  • References Cited
  • Appendix 1. Profiles of Colorado River Water Surface and Thalweg Elevation, From Lees Ferry To Pearce Ferry, Arizona, 2021
Publication type Report
Publication Subtype USGS Numbered Series
Title Continuous and high-resolution longitudinal profiles of the water surface and riverbed elevation for 282 miles of the Colorado River from Lees Ferry to Pearce Ferry, Arizona, 2021
Series title Scientific Investigations Report
Series number 2026-5010
DOI 10.3133/sir20265010
Publication Date May 26, 2026
Year Published 2026
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Southwest Biological Science Center
Description Report: vii, 40 p.; Data Release
Country United States
State Arizona
Other Geospatial Colorado River
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Additional publication details