Anchor ice formation in streams: a field study

Stickler, Morten; Alfredsen, Knut

doi:10.1002/hyp.7349

Cited by 60 publications

(41 citation statements)

References 23 publications

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“…Anchor ice is usually initiated by the accumulation of tiny ice particles that have adhesive features in supercooled water and therefore attach to in-stream vegetation, coarse material and large wood (Stickler and Alfredsen 2009;Lind and others 2014a). Suspended ice is created when anchor ice dams collapse or when water recedes during winter, thereby leaving ice elevated above the water surface (Prowse 1995;Turcotte and Morse 2013).…”

Section: Ice Studiesmentioning

confidence: 99%

How Do Biota Respond to Additional Physical Restoration of Restored Streams?

et al. 2016

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Restoration of channelized streams by returning coarse sediment from stream edges to the wetted channel has become a common practice in Sweden. Yet, restoration activities do not always result in the return of desired biota. This study evaluated a restoration project in the Vindel River in northern Sweden in which practitioners further increased channel complexity of previously restored stream reaches by placing very large boulders (>1 m), trees (>8 m), and salmonid spawning gravel from adjacent upland areas into the channels. One reach restored with basic methods and another with enhanced methods were selected in each of ten different tributaries to the main channel. Geomorphic and hydraulic complexity was enhanced but the chemical composition of riparian soils and the communities of riparian plants and fish did not exhibit any clear responses to the enhanced restoration measures during the first 5 years compared to reaches restored with basic restoration methods. The variation in the collected data was among streams instead of between types of restored reaches. We conclude that restoration is a disturbance in itself, that immigration potential varies across landscapes, and that biotic recovery processes in boreal river systems are slow. We suggest that enhanced restoration has to apply a catchment-scale approach accounting for connectivity and availability of source populations, and that low-intensity monitoring has to be performed over several decades to evaluate restoration outcomes.

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Section: Ice Studiesmentioning

confidence: 99%

How Do Biota Respond to Additional Physical Restoration of Restored Streams?

et al. 2016

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“…Frazil ice may accumulate in slowflowing areas (hanging dam) or may adhere to the stream bottom, producing anchor ice ( figure 3; Stickler and Alfredsen 2009). In steeper reaches (i.e., with a gradient of more than 0.2%), anchor ice dams can temporarily block streamflow, can change riffles into a stepwise series of pools, and can finally initiate freeze-up of the entire channel.…”

Section: Subsurface Icementioning

confidence: 99%

“…In steeper reaches (i.e., with a gradient of more than 0.2%), anchor ice dams can temporarily block streamflow, can change riffles into a stepwise series of pools, and can finally initiate freeze-up of the entire channel. Subsurface ice formation is most pronounced in early winter (Stickler and Alfredsen 2009), but hanging dams may persist throughout winter (KomadinaDouthwright et al 1997).…”

Section: Subsurface Icementioning

confidence: 99%

“…The impacts often function as press disturbances of long-term persistence that influence the natural disturbance regime of a river (Lake 2000). Abundant evidence of human alterations of winter disturbances is found in ice-dominated river systems with hydropower production, in which increased and more variable winter flows due to production releases can result in recurrent breakups ), incomplete freeze-up (Stickler and Alfredsen 2009), and excessive subsurface ice formation following prolonged periods of supercooling (Alfredsen and Tesaker 2002). Repeated thawing and refreezing of border ice (box 2) can result in bottomfast freezing of shallow, slow-flowing edge waters and in the cutting off of important fish refugia (Alfredsen and Tesaker 2002).…”

Section: Human Alterations Of Winter Disturbances and Refugiamentioning

confidence: 99%

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Winter Disturbances and Riverine Fish in Temperate and Cold Regions

Weber¹,

Nilsson²,

Lind³

et al. 2013

BioScience

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“…Specifically, steep streams are subject to significant changes in their physical environment during ice formation periods despite only minimal (or no) changes in discharge. In these environments the ice regime is dominated by dynamic ice formation when the water temperature becomes supercooled (water temperature, T W , <08C) (Devik, 1944;Stickler and Alfredsen, 2009). Tiny ice particles (frazil) that form on the water surface are transported by turbulence and deposited atop the stream bed, forming ice on the stream bottom (anchor ice).…”

Section: Introductionmentioning

confidence: 99%

The influence of dynamic ice formation on hydraulic heterogeneity in steep streams

Stickler

Alfredsen

Linnansaari

et al. 2010

River Research & Apps

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During winter, different types of ice formation are commonly observed in northern boreal stream systems. Although largely overlooked today, river ice has profound effects on in-stream hydraulics and therefore ice processes should be considered in freshwater stream management and assessment. In particular, limited knowledge exists about the impacts of dynamic ice formation on stream environments. Results presented from the changes of in-stream heterogeneity in three steep stream environments caused by dynamic ice formation demonstrate that the formation of anchor ice and anchor ice dams may induce significant backwater effects by increasing wetted areas (maximum 43%) and water depths (maximum 241%) and reducing water velocities (maximum 70%); independent of minimal changes in discharge. Consequently, stream environments are transformed from fast-flow to slow-flow areas, even on a short temporal scale (<12 h). Furthermore, the anchor ice build-up initiated static (surface) ice formation due to reduced local water velocities upstream ice dams. Thus, dynamic ice formation plays a key role in the balanced ice regime in steep stream environments and contributes largely to stable static ice cover in these environments. Observations from the present study suggest that the current paradigm emphasizing the role of discharge as the main controller of in-stream heterogeneity may call for a modification in steep streams that experience seasonal ice formation. This is particularly important if future hydraulic-/habitat models and assessment tools are to be implemented in freshwater management to realistically characterize steep stream environments in cold climate regions on a seasonal scale.

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Anchor ice formation in streams: a field study

Cited by 60 publications

References 23 publications

How Do Biota Respond to Additional Physical Restoration of Restored Streams?

How Do Biota Respond to Additional Physical Restoration of Restored Streams?

Winter Disturbances and Riverine Fish in Temperate and Cold Regions

The influence of dynamic ice formation on hydraulic heterogeneity in steep streams

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