Sandbar response in Marble and Grand Canyons, Arizona, following the 2008 high-flow experiment on the Colorado River

Scientific Investigations Report 2010-5015
Prepared in cooperation with Northern Arizona University and Utah State University
By: , and 



A 60-hour release of water at 1,203 cubic meters per second (m3/s) from Glen Canyon Dam in March 2008 provided an opportunity to analyze channel-margin response at discharge levels above the normal, diurnally fluctuating releases for hydropower plant operations. We compare measurements at sandbars and associated campsites along the mainstem Colorado River, downstream from Glen Canyon Dam, at 57 locations in Marble and Grand Canyons. Sandbar and main-channel response to the 2008 high-flow experiment (2008 HFE) was documented by measuring bar and bed topography at the study sites before and after the controlled flood and twice more in the following 6 months to examine the persistence of flood-formed deposits. The 2008 HFE caused widespread deposition at elevations above the stage equivalent to a flow rate of 227 m3/s and caused an increase in the area and volume of the high-elevation parts of sandbars, thereby increasing the size of campsite areas. In this study, we differentiate between four response styles, depending on how sediment was distributed throughout each study site. Then, we present the longitudinal pattern relevant to the different response styles and place the site responses in context with two previous high-release experiments conducted in 1996 and 2004. We find that (1) nearly every measured sandbar aggraded above the 227-m3/s water-surface elevation, resulting in sandbars as large or larger than occurred following previous high flows; (2) reaches closest to Glen Canyon Dam were characterized by a greater percentage of sites that incurred net erosion, although the total sand volume in all sediment-flux monitoring reaches was greater following the 2008 HFE than following previous high flows; and (3) longitudinal differences in topographic response in eddies and in the channel suggest a greater and more evenly distributed sediment supply than existed during previous controlled floods from Glen Canyon Dam.

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Sandbar response in Marble and Grand Canyons, Arizona, following the 2008 high-flow experiment on the Colorado River
Series title Scientific Investigations Report
Series number 2010-5015
DOI 10.3133/sir20105015
Year Published 2010
Language English
Publisher U.S. Geological Survey
Contributing office(s) Southwest Biological Science Center
Description vi, 52 p.
Time Range Start 2008-03-01
Time Range End 2008-03-31
Country United States
State Arizona
Other Geospatial Colorado, River, Grand Canyon, Marble Canyon
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details