Optimal timing of high-flow experiments for sandbar deposition

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Abstract

Sediment-transport theory and field measurements indicate that the greatest or most efficient deposition of sand in eddies occurs during controlled floods (a.k.a. High-Flow Experiments or HFEs) when the greatest amount of the finest sand is available on the bed of the Colorado River (Topping and others, 2010). Conducting HFEs when the sand on the bed of the Colorado River is depleted and coarse can result in relatively widespread erosion of sandbars during HFEs (Hazel and others, 1999; Schmidt, 1999, Rubin and others, 2002). Here we show that sandbar building during HFEs is maximized during periods following tributary floods that resupply the river with large amounts of very fine sand. Conversely, sandbars erode during HFEs when the antecedent sand supply is depleted and coarse. HFEs should be conducted during the fall-winter months of October through January to take advantage of having the greatest amount of very fine sand available on the bed of the Colorado River in Marble Canyon. Conducting HFEs in the spring would necessitate lowering dam operations over the winter months in order to retain the very fine sand supplied during the previous summer.

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Additional publication details

Publication type Conference Paper
Title Optimal timing of high-flow experiments for sandbar deposition
Year Published 2019
Language English
Publisher US Bureau of Reclamation Glen Canyon Dam Adaptive Management Program
Contributing office(s) Southwest Biological Science Center
Description 7 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title High-Flow Experiments Assessment Extended Abstracts
First page 3
Last page 9
Conference Title Adaptive Management Work Group Meeting
Conference Location Tempe, AZ
Conference Date March 6-7, 2019
Country United States
State Arizona
Other Geospatial Colorado River, Eastern Grand Canyon, Lower Marble Canyon, Upper Marble Canyon