Aquatic Food Base Response to the 1996 Test Flood Below Glen Canyon Dam, Colorado River, Arizona

Shannon, Joseph P.; Blinn, Dean W.; McKinney, T. D.; Benenati, Emma P.; Wilson, Kevin P.; O’Brien, Chris

doi:10.1890/1051-0761(2001)011[0672:afbrtt]2.0.co;2

Cited by 45 publications

(41 citation statements)

References 29 publications

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“…Results also show that high flow events can remove these populations, leaving the unimpounded reaches of the river devoid of appropriate spawning habitat for periods of at least 1 year. This scouring of macrophyte populations has been reported in other studies (Brierley et al, 1989;Shannon et al, 2001;Schaller et al, 2004) and populations may take years to return to their original levels. This loss of macrophytes has important ramifications on other components of the ecosystem, since they provide habitat for zooplankton and fish (Irvine et al, 1989;Basu et al, 2000), they filter nutrients and stabilize sediments (Kemp et al, 1984) and affect phytoplankton and filamentous algal populations (Wigand et al, 2000).…”

Section: Discussionsupporting

confidence: 77%

Effects of water level fluctuations on Vallisneria nana in the Burnett River in Southeast Queensland, Australia

Duivenvoorden

2008

River Research & Apps

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Changes in aquatic macrophyte populations in the Burnett River in southeast Queensland, Australia are described with respect to the effects of water level fluctuations and possible impact on the Queensland lungfish (Neoceratodus forsteri). This protected fish relies on macrophyte beds as spawning and nursery areas. Studies were conducted prior to, during and following construction of a new weir on the river. Comparative results of impounded and non-impounded sites were conducted to investigate seasonal and inter-annual changes in macrophytes and the effects of both a rapid rise in water level when the impoundment first filled and a decline, on new plants in shallow water. Macrophyte communities in newly inundated areas were studied to determine the time taken for seedlings to emerge and reach a cover sufficient to represent spawning habitats for the lungfish. Vallisneria nana dominated the macrophyte beds, which were scoured from the river by a large flow event in May 1998, the effects of which persisted for at least 1 year. Most newly emerging seedlings of Vallisneria perished following a small decline of 7 cm in water level. Decrease in plant biomass and death of established plants in highly turbid water resulted within 6-9 weeks following larger water level rises of 4.0-5.5 m in the new impoundment. In the period leading up to the lungfish-spawning season at least 5 months is required for submerged plants to reach the 90% cover preferred for spawning. Implications of the results for water level management and lungfish populations are discussed.

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Section: Discussionsupporting

confidence: 77%

Effects of water level fluctuations on Vallisneria nana in the Burnett River in Southeast Queensland, Australia

Duivenvoorden

2008

River Research & Apps

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“…If control points are upstream of losing river reaches, downstream flows are likely to fall below the acceptable level. Comparable problems due to longitudinal variation apply to 'channel maintenance flows', 'flushing flows', 'flow pulses' or any other hydrological index or flow regime component that is considered ecologically valuable (Tockner et al, 2000;Shannon et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

Longitudinal river ecohydrology: flow variation down the lengths of alluvial rivers

Larned¹,

Schmidt²,

Datry³

et al. 2011

Ecohydrology

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Longitudinal flow variation is an emerging field of study in river ecohydrology. Longitudinal changes in the frequencies, magnitudes, durations and timing of floods, low-flows and intermittence create a dynamic environment for flow-dependent species and ecological processes. Analyses of flow variation and flow-ecosystem relationships in the longitudinal dimension require synoptic flow time-series at multiple sites along a river. Complex channel geomorphology and a scarcity of rivers equipped with multiple flow gauges have slowed progress in longitudinal ecohydrology. The empirical longitudinal flow model (ELFMOD) is a new statistical tool for estimating flows at multiple points along rivers; which circumvents the requirement for multiple gauges. In this study, we used ELFMOD to explore longitudinal flow variation in four alluvial rivers from different geological terrains and climate zones: the Albarine (France), Methow (USA) and Selwyn and Orari (New Zealand). Differences among rivers in longitudinal and temporal flow variation were evident on date ð location flow matrices and longitudinal profiles. There were notable differences among longitudinal gradients in flow magnitude and flow percentiles, and in the recurrence, extent, and rate of expansion and contraction of dry river reaches. There were also large differences in longitudinal flow-permanence patterns. Temporal variation in the lengths of dry channel and numbers of dry reaches was predominately seasonal in the Albarine and Methow, and interannual in the Orari and Selwyn. Broad differences among the rivers in longitudinal flow patterns correspond to differences in the configuration of hydrogeomorphic discontinuities such as tributary confluences, channel divergences and convergences, and lithological contacts.

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“…There also was a major decrease in periphyton AFDM at the Upper site after the June flood, although no effect was seen in periphyton chlorophyll concentrations. Others have noted that flood frequency is related negatively to periphyton chlorophyll abundance (Biggs, 1995), although this relationship occurs only if the algae are scoured (Shannon et al, 2001). Aquat.…”

Section: Discussionmentioning

confidence: 99%

“…For example, sediment supply and mobility may increase downstream as contributions from sideslopes and tributaries increase. Near the dam, disturbance may simply be from sheer stress associated with higher flows, whereas the effects of sediment scouring probably increases further downstream (Shannon et al, 2001). For instance, the first lateral debris flow into the Spöl River occurs around 250 m below the dam, thus disturbance by sediment scouring is probably minimal upstream of this debris flow.…”

Section: Introductionmentioning

confidence: 99%

“…However, there have been only a handful of studies addressing the use of sequential floods (intra-annual and annual) for river restoration (Rulifson and Manooch, 1993;Molles et al, 1998;Robinson et al, 2003). Although incorporated into the Glen Canyon flood study (Shannon et al, 2001;Valdez et al, 2001), few other studies have examined the longitudinal effects of experimental floods below large dams. Here we report on the longitudinal effects of three floods on stream benthos in the River Spöl downstream from the Livigno Reservoir.…”

Section: Introductionmentioning

confidence: 99%

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Longitudinal effects of experimental floods on stream benthos downstream from a large dam

Jakob

Robinson

Uehlinger

2003

Aquatic Sciences - Research Across Boundaries

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Abstract.We examined the longitudinal effects of 3 experimental floods on seston, periphyton, and macroinvertebrates in a regulated river downstream from a large reservoir in the Swiss Alps. In addition, suspended organic sediments, in conjunction with conductivity and turbidity, were measured during each flood. Three study reaches were selected downstream from the reservoir: an Upper site ca 150 m, a Middle site at 1.2 km, and a Lower site at 2.3 km from the dam. The Upper site was located upstream of any significant source of sediments. No flood effect was observed on water temperature, although river temperatures and diel amplitudes increased progressively downstream from the dam. Most organic sediments were mobilized and transported within the first few hours of each flood, with the pulse in sediments typically occuring later (after peak discharge) and being more prolonged at the Lower site. Turbidity generally decreased Aquat. Sci. 65 (2003) Dübendorf, 2003 Aquatic Sciences during the flood season, perhaps in response to lower amounts of fines and reductions in periphyton biomass. Seston concentrations (as chlorophyll a and AFDM) were lowest at the Upper site, and typically decreased following each flood. The flood response in seston was lowest at the Upper site and more pronounced at the Middle and Lower sites. Periphyton biomass also was lowest at the Upper site, and the flood effects were significant only in the Middle and Lower sites. In contrast, macroinvertebrate densities were similar between the Upper and Lower sites, and both sites exhibited a similar response to the floods. These results indicate a longitudinal response of river benthos to flooding below the reservoir that partly reflects the examined benthic constituent (periphyton or zoobenthos) and the longitudinal differences in the degree and type (e. g., flow in combination with sediment mobility and scouring) of disturbance.223 -231 1015-1621/03/030223-09 DOI 10.1007/s00027-003-0662-9 © EAWAG,

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Aquatic Food Base Response to the 1996 Test Flood Below Glen Canyon Dam, Colorado River, Arizona

Cited by 45 publications

References 29 publications

Effects of water level fluctuations on Vallisneria nana in the Burnett River in Southeast Queensland, Australia

Effects of water level fluctuations on Vallisneria nana in the Burnett River in Southeast Queensland, Australia

Longitudinal river ecohydrology: flow variation down the lengths of alluvial rivers

Longitudinal effects of experimental floods on stream benthos downstream from a large dam

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