Channel units in small, high gradient streams on Vancouver Island, British Columbia

Halwas, Karen L.; Church, Michael

doi:10.1016/s0169-555x(01)00136-2

Cited by 74 publications

(47 citation statements)

References 31 publications

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“…Boulders and cobbles are typically the major structural elements in steep gradient upper streams, whereas sand and smaller sediments predominate in the lower reaches [55]. There have been a large number of studies on the macroinvertebrate-substrate relationship, most of which have revealed that macroinvertebrate diversity and density increase with higher heterogeneity due to the available stable and diverse microhabitats (e.g., [10,43]).…”

Section: Environmental Relationships With Macroinvertebrate Distributionmentioning

confidence: 99%

Spatial Distribution of Benthic Macroinvertebrate Assemblages in Relation to Environmental Variables in Korean Nationwide Streams

Jun

Kim

et al. 2016

Water

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Conserving and enhancing freshwater biodiversity are global issues to ensure ecosystem integrity and sustainability. To meet this, it is critical to understand how the biological assemblages are determined by environmental gradients in different spatial scales. Nevertheless, information on their large-scale environmental relationships remains scarce in Korea. We aimed to understand nationwide spatial distribution patterns of benthic macroinvertebrates and important environmental factors affecting their distribution in 388 streams and rivers across Korea. A total of 340 taxa, belonging to 113 families in 23 orders of five phyla, were identified. Assemblage composition in most Korean streams included a few predominant colonizers and a majority of rare taxa. Cluster analysis based on benthic macroinvertebrates classified a total of 720 sampling sites into five clusters according to the pollution levels from fast-flowing less polluted streams with low electrical conductivity to moderately or severely polluted streams with high electrical conductivity and slow water velocity. Canonical correspondence analysis revealed that altitude, water velocity and streambed composition were the most important determinants, rather than watershed and water chemistry variables, for explaining the variation in macroinvertebrate assemblage patterns. The results provide basic information for establishing the conservation and restoration strategies of macroinvertebrate biodiversity against anthropogenic disturbances and developing more confident bio-assessment tools for diagnosing stream ecosystem integrity.

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Section: Environmental Relationships With Macroinvertebrate Distributionmentioning

confidence: 99%

Spatial Distribution of Benthic Macroinvertebrate Assemblages in Relation to Environmental Variables in Korean Nationwide Streams

Jun

Kim

et al. 2016

Water

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“…The twenty-three river types were developed from previous geomorphological research (e.g. Schumm, 1985;Knighton and Nanson, 1993;Rosgen, 1994;Nanson and Knighton, 1996;Montgomery and Buffington, 1997;Church, 2006;Fuller et al, 2013;Nanson, 2013) with additional information on geomorphic units in confined and bedrock river reaches obtained from Grant et al (1990) and Halwas and Church (2002).…”

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confidence: 99%

A multi-scale hierarchical framework for developing understanding of river behaviour to support river management

et al. 2015

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Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. 1The following paper is the final version prior to publication on 22 September 2015. are proposed, the way in which indicators could contribute to classification is discussed. All of the methods described in Table 1 consider a hierarchy of spatial units, but the degree to which they develop the other aspects of the conceptual approach proposed by Frissell et al.(1986) varies widely.2. Many of the frameworks focus entirely on hydromorphological processes and forms that are either directly measured or inferred. This is because interactions between processes and forms control the dynamic morphology or behaviour of rivers and their mosaics of habitats.Hydromorphological processes drive longitudinal and lateral connectivity within river networks and corridors, the assemblage and turnover of physical habitats, and the sedimentary and vegetation structures associated with those habitats.3. Some frameworks are conceptual, providing a way of thinking about or structuring analyses of river systems, and interpreting their processes, morphology and function (e.g. Frissell et al., 1986;Habersack, 2000;Fausch et al., 2002;Thorp et al., 2006;Beechie et al., 2010;McCluney et al., 2014). Some frameworks are more quantitative, generating one or more indices or classifications of spatial units that support assessment of river systems (e.g. Rosgen, 1994;González del Tánago and García de Jalón, 2004;Merovich et al., 2013;Rinaldi et al., 2013Rinaldi et al., , 2015a MacDonald, 2002;Brierley and Fryirs, 2005;Beechie et al., 2010; Rinaldi et al., 2013a Rinaldi et al., , 2015.In some cases, theoretical or historical analyses or consideration of specific future scenarios are used to develop space-time understanding that can support management decisionmaking (e.g. Buffington, 1997, 1998;Montgomery and MacDonald, 2002;Benda et al., 2004;Brierley and Fryirs, 2005;McCluney et al., 2014 , 1997, 1998Montgomery and MacDonald, 2002;Benda et al., 2004;Brierley and Fryirs, 2005;Merovich et al., 2013;Rinaldi et al., 2013Rinaldi et al., , 2015a. Furthermore, some of the frameworks include indicators of human pressures and their impacts (e.g. Merovich et al., 2013;McCluney et al., 2014;Rinaldi et al., 2013Rinaldi et al., , 2015a.6. Finally, although most frameworks could be described as incorporating processes to some degree, some methods are particularly process-based, even when processes are inferred from forms and associations rather than being quantified by direct measurements.Frameworks that consider temporal dynamics and trajectories of historical change (see point 4, above) are particularly effective in developing understanding of processes and the impacts of changed processes cascading through time and across spatial scales.Although the list of frameworks presented in Table 1 is far from comprehensive, ...

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“…Bedrock or semi-alluvial channels (see Meshkova et al, 2012) received little attention in the literature for much of the 20th century due to the concentration of human interests in lowland alluvial valleys (Halwas and Church, 2002;Toone et al, 2014). The relatively recent recognition of steep headwater channels as critical habitats and sediment sources, as well as their role in landscape evolution, has encouraged research in recent decades, with a particular focus on process-based morphology (Montgomery and Buffington, 1997), the nature and rates of bedrock incision (Sklar and Dietrich, 1998;Tinkler and Wohl, 1998), and the numerical modelling of sediment transport and bedrock incision (see Turowski et al, 2007Turowski et al, , 2009Lague, 2010).…”

Section: Importance Of Bedrock Channel Morphology and Processesmentioning

confidence: 99%

“…Recent interest in the process-based morphology of bedrock channels has led to the creation of a number of morphological classification models for steep mountain streams (Wohl and Merritt, 2001). An important contribution by Montgomery and Buffington (1997) outlined a framework for reach-scale classification of mountain streams into visually identifiable and physically distinct categories which has been applied and adapted by a number of subsequent researchers to describe bedrock channels in specific catchments (Halwas and Church, 2002;Golden and Springer, 2006;Thompson et al, 2006;Wohl and Merritt, 2008). The Montgomery and Buffington (1997) classification includes an idealised downstream progression from bedrock and colluvial zones into fluvial-dominated zones with a progression from cascade, step-pool, plane-bed, pool-riffle and into duneripple reach morphologies (Fig.…”

Section: Importance Of Bedrock Channel Morphology and Processesmentioning

confidence: 99%

Hitting rock bottom: morphological responses of bedrock-confined streams to a catastrophic flood

et al. 2015

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Abstract. The role of extreme events in shaping the Earth's surface is one that has held the interests of Earth scientists for centuries. A catastrophic flood in a tectonically quiescent setting in eastern Australia in 2011 provides valuable insight into how semi-alluvial channels respond to such events. Field survey data (3 reaches) and desktop analyses (10 reaches) with catchment areas ranging from 0.5 to 168 km 2 show that the predicted discharge for the 2011 event ranged from 415 to 933 m 3 s −1 , with unit stream power estimates of up to 1077 W m −2 . Estimated entrainment relationships predict the mobility of the entire grain-size population, and field data suggest the localised mobility of boulders up to 4.8 m in diameter. Analysis of repeat lidar data demonstrates that all reaches (field and desktop) were areas of net degradation via extensive scouring of coarse-grained alluvium with a strong positive relationship between catchment area and normalised erosion (R 2 = 0.72-0.74). The extensive scouring in the 2011 flood decreased thalweg variance significantly removing previous step pools and other coarse-grained in-channel units, forming lengths of plane-bed (cobble) reach morphology. This was also accompanied by the exposure of planar bedrock surfaces, marginal bedrock straths and bedrock steps. Post-flood field data indicate a slight increase in thalweg variance as a result of the smaller 2013 flood rebuilding the alluvial overprint with pool-riffle formation. However, the current form and distribution of channel morphological units does not conform to previous classifications of bedrock or headwater river systems. This variation in postflood form indicates that in semi-alluvial systems extreme events are significant for re-setting the morphology of in-channel units and for exposing the underlying lithology to ongoing erosion.

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Channel units in small, high gradient streams on Vancouver Island, British Columbia

Cited by 74 publications

References 31 publications

Spatial Distribution of Benthic Macroinvertebrate Assemblages in Relation to Environmental Variables in Korean Nationwide Streams

Spatial Distribution of Benthic Macroinvertebrate Assemblages in Relation to Environmental Variables in Korean Nationwide Streams

A multi-scale hierarchical framework for developing understanding of river behaviour to support river management

Hitting rock bottom: morphological responses of bedrock-confined streams to a catastrophic flood

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