Turbid releases from Glen Canyon Dam, Arizona, following rainfall-runoff events of September 2013

Lake and Reservoir Management
By:  and 

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Abstract

Glen Canyon Dam is a large dam on the Colorado River in Arizona. In September 2013, it released turbid water following intense thunderstorms in the surrounding area. Turbidity was >15 nephelometric turbidity units (NTU) for multiple days and >30 NTU at its peak. These unprecedented turbid releases impaired downstream fishing activity and motivated a rapid-response field excursion. At 5 locations upstream from the dam, temperature, specific conductance, dissolved oxygen, chlorophyll a, and turbidity were measured in vertical profiles. Local streamflow and rainfall records were retrieved, and turbidity and specific conductance data in dam releases were evaluated. Profiling was conducted to determine possible sources of turbidity from 3 tributaries nearest the dam, Navajo, Antelope, and Wahweap creeks, which entered Lake Powell as interflows during this study. We discuss 4 key conditions that must have been met for tributaries to influence turbidity of dam releases: tributary flows must have reached the dam, tributary flows must have been laden with sediment, inflow currents must have been near the depth of dam withdrawals, and the settling velocity of particles must have been slow. We isolate 2 key uncertainties that reservoir managers should resolve in future similar studies: the reach of tributary water into the reservoir thalweg and the distribution of particle size of suspended sediment. These uncertainties leave the source of the turbidity ambiguous, although an important role for Wahweap Creek is possible. The unique combination of limnological factors we describe implies that turbid releases at Glen Canyon Dam will continue to be rare.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Turbid releases from Glen Canyon Dam, Arizona, following rainfall-runoff events of September 2013
Series title Lake and Reservoir Management
DOI 10.1080/10402381.2017.1293756
Volume 33
Issue 3
Year Published 2017
Language English
Publisher Taylor & Francis
Contributing office(s) Southwest Biological Science Center
Description 6 p.
First page 211
Last page 216
Country United States
State Arizona
Other Geospatial Glen Canyon Dam