2008 High-flow experiment at Glen Canyon Dam: Morphologic response of eddy-deposited sandbars and associated aquatic backwater habitats along the Colorado River in Grand Canyon National Park

Grams, Paul E.; Schmidt, John C.; Andersen, Matthew E.

doi:10.3133/ofr20101032

Cited by 12 publications

(13 citation statements)

References 2 publications

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“…Since 1996, a series of experimental high‐flow events from GCD have been conducted to mimic elements of the natural hydrograph and create historic geomorphic features, such as backwaters. Our combined habitat and fish data come from 1–3 years after the March 2008 high‐flow experiment; however, it is known that sandbars, and associated backwaters, are most prevalent directly after high‐flow experiments and disappear over time because of erosion (Grams et al ., ). In addition, we did not know whether the prevalence of backwaters in our study area was representative of conditions within the LCR aggregation (Figure ).…”

Section: Methodsmentioning

confidence: 97%

“…Juvenile native fish including Colorado pikeminnow, humpback chub, bluehead sucker Catostomus discobolus, flannelmouth sucker Catostomus latipinnis and speckled dace Rhinichthys osculus use backwaters in both the upper and lower Colorado River basins (Bestgen et al, 2006;Grams et al, 2010). Backwater habitats can be created and modified by management actions such as experimental flows from GCD (Grams et al, 2010). However, fundamental questions remain related to the role backwaters play in native fish ecology.…”

Section: Introductionmentioning

confidence: 99%

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Do Management Actions to Restore Rare Habitat Benefit Native Fish Conservation? Distribution of Juvenile Native Fish Among Shoreline Habitats of the Colorado River

Dodrill

Yackulic

Gerig

et al. 2014

River Research & Apps

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Many management actions in aquatic ecosystems are directed at restoring or improving specific habitats to benefit fish populations. In the Grand Canyon reach of the Colorado River, experimental flow operations as part of the Glen Canyon Dam Adaptive Management Program have been designed to restore sandbars and associated backwater habitats. Backwaters can have warmer water temperatures than other habitats, and native fish, including the federally endangered humpback chub Gila cypha, are frequently observed in backwaters, leading to a common perception that this habitat is critical for juvenile native fish conservation. However, it is unknown how fish densities in backwaters compare with that in other habitats or what proportion of juvenile fish populations reside in backwaters. Here, we develop and fit multispecies hierarchical models to estimate habitat-specific abundances and densities of juvenile humpback chub, bluehead sucker Catostomus discobolus, flannelmouth sucker Catostomus latipinnis and speckled dace Rhinichthys osculus in a portion of the Colorado River. Densities of all four native fish were greatest in backwater habitats in 2009 and 2010. However, backwaters are rare and ephemeral habitats, so they contain only a small portion of the overall population. For example, the total abundance of juvenile humpback chub in this study was much higher in talus than in backwater habitats. Moreover, when we extrapolated relative densities based on estimates of backwater prevalence directly after a controlled flood, the majority of juvenile humpback chub were still found outside of backwaters. This suggests that the role of controlled floods in influencing native fish population trends may be limited in this section of the Colorado River.

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Section: Methodsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Do Management Actions to Restore Rare Habitat Benefit Native Fish Conservation? Distribution of Juvenile Native Fish Among Shoreline Habitats of the Colorado River

Dodrill

Yackulic

Gerig

et al. 2014

River Research & Apps

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“…These lateral habitats included braided channel systems in unconstrained valleys such as the Missouri River below the current location of Garrison Dam. Even in canyon‐bound systems, lateral habitats such as backwaters may be important rearing habitats for juvenile native fishes 58 and are maintained by upstream sediment sources 59 . These lateral habitats are maintained by upstream channel adjustments and bank erosion from the mainstem in large unconfined river systems, whereas they are maintained by tributary inputs in confined systems.…”

Section: Discussionmentioning

confidence: 99%

“…Even in canyon-bound systems, lateral habitats such as backwaters may be important rearing habitats for juvenile native fishes 58 and are maintained by upstream sediment sources. 59 These lateral habitats are maintained by upstream channel adjustments and bank erosion from the mainstem in large unconfined river systems, whereas they are maintained by tributary inputs in confined systems. Moreover, these habitats are increasingly rare given reduced sediment input from upstream sources.…”

Section: Discussionmentioning

confidence: 99%

Dams in the Cadillac Desert: downstream effects in a geomorphic context

Sabo

Bestgen

Graf

et al. 2012

Annals of the New York Academy of Sciences

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This paper was motivated by the 25th anniversary of the publication of Marc Reisner's book, Cadillac Desert: The American West and its Disappearing Water. Dams are ubiquitous on rivers in the United States, and large dams and storage reservoirs are the hallmark of western U.S. riverscapes. The effects of dams on downstream river ecosystems have attracted much attention and are encapsulated in the serial discontinuity concept (SDC). In the SDC, dams create abrupt shifts in continua of downstream changes in physical and biotic properties. In this paper, we develop a framework for understanding how channel geometry and network structure influence how the physical components of habitat and the biota rebound from discontinuities set up by large dams. We apply this framework to data describing the flow regime, temperature, sediment flux, and fish community composition below Garrison Dam on the Missouri River, Glen Canyon Dam on the Colorado River, and Flaming Gorge Dam on the Green River. Sediment flux in dam tailwaters is under strong control by channel geometry. By contrast, dam-related changes in temperature and flow variation are not significantly modulated by channel geometry or tributary inputs if flow volumes are small (Missouri and Colorado River tributaries). Instead, small tributaries provide near-native conditions (flow and temperature variation) and, as such, provide key refuges for biota from novel habitats in mainstem rivers below large dams. Unregulated tributaries that are large relative to their respective mainstem (e.g., Yampa River) provide refuges as well as significant amelioration of flow and temperature effects from upstream dams. Finally, the proportion of native fish increases with distance from dam and exhibits sharp increases near tributary junctions. These results suggest that tributaries-even minor ones in terms of relative discharge-act as key refugia for native species in regulated river networks. Moreover, large, unregulated tributaries are key to restoring continuity in physical habitat and the biota in large regulated rivers.

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“…Current available ecosystem restoration strategies include targeting and managing specific components such as flood restoration or modification of structures to pass sediment or allow fish passage (Richter and Thomas, 2007). For example, the Grand Canyon Monitoring Research Center has conducted high flow experiments to correspond with seasons of peak tributary sediment loads to maximize downstream delivery of sediment to replenish sandbars (Grams et al, 2010). Wohl et al (2015) hypothesized that the restoration of the 'natural flow regime' (Poff et al, 1997) will likely only be successful with inclusion of the 'natural sediment regime'.…”

Section: Introductionmentioning

confidence: 99%

Flood Effects Provide Evidence of an Alternate Stable State from Dam Management on the Upper Missouri River

Skalak¹,

Benthem²,

Hupp³

et al. 2016

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We examine how historic flooding in 2011 affected the geomorphic adjustments created by dam regulation along the approximately 120 km free flowing reach of the Upper Missouri River bounded upstream by the Garrison Dam (1953) and downstream by Lake Oahe Reservoir (1959) near the City of Bismarck, ND, USA. The largest flood since dam regulation occurred in 2011. Flood releases from the Garrison Dam began in May 2011 and lasted until October, peaking with a flow of more than 4200 m 3 s À1 . Channel cross-section data and aerial imagery before and after the flood were compared with historic rates of channel change to assess the relative impact of the flood on the river morphology. Results indicate that the 2011 flood maintained trends in island area with the loss of islands in the reach just below the dam and an increase in island area downstream. Channel capacity changes varied along the Garrison Segment as a result of the flood. The thalweg, which has been stable since the mid-1970s, did not migrate. And channel morphology, as defined by a newly developed shoaling metric, which quantifies the degree of channel braiding, indicates significant longitudinal variability in response to the flood. These results show that the 2011 flood exacerbates some geomorphic trends caused by the dam while reversing others. We conclude that the presence of dams has created an alternate geomorphic and related ecological stable state, which does not revert towards pre-dam conditions in response to the flood of record. This suggests that management of sediment transport dynamics as well as flow modification is necessary to restore the Garrison Segment of the Upper Missouri River towards pre-dam conditions and help create or maintain habitat for endangered species. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

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2008 High-flow experiment at Glen Canyon Dam: Morphologic response of eddy-deposited sandbars and associated aquatic backwater habitats along the Colorado River in Grand Canyon National Park

Cited by 12 publications

References 2 publications

Do Management Actions to Restore Rare Habitat Benefit Native Fish Conservation? Distribution of Juvenile Native Fish Among Shoreline Habitats of the Colorado River

Do Management Actions to Restore Rare Habitat Benefit Native Fish Conservation? Distribution of Juvenile Native Fish Among Shoreline Habitats of the Colorado River

Dams in the Cadillac Desert: downstream effects in a geomorphic context

Flood Effects Provide Evidence of an Alternate Stable State from Dam Management on the Upper Missouri River

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