INVESTIGADORES
ORFEO Oscar
capítulos de libros
Título:
Large river channel confluences
Autor/es:
PARSONS, D., BEST, J., LANE, S., KOSTASCHUK, R., HARDY, R., ORFEO, O., AMSLER, M., AND SZUPIANY, R.
Libro:
River Confluences, Tributaries and the Fluvial Network
Editorial:
John Wiley & Sons
Referencias:
Lugar: West Sussex; Año: 2008; p. 73 - 91
Resumen:
River channel confluences are a fundamental component of fluvial systems and are
ubiquitous within both dendritic drainage networks and most channel planforms. Despite
the clear importance of fully understanding the processes and dynamics of river
channel confluences, our current understanding is based largely on laboratory experiments
(e.g. Mosley, 1976; Best, 1988; Best and Roy, 1991) and on the observations,
measurements and numerical modelling of small-scale natural junctions, which are
often less than tens of metres wide (Rhoads and Kenworthy, 1998; Bradbrook et al.,et al.,
River Confluences, Tributaries and the Fluvial Network Edited by Stephen P. Rice, Andr´e G. Roy
and Bruce L. Rhoads C 2008 JohnWiley & Sons, Ltd
PIC OTE/SPH
PIC OTE/SPH
and Bruce L. Rhoads C 2008 JohnWiley & Sons, Ltd
PIC OTE/SPH
PIC OTE/SPH
Edited by Stephen P. Rice, Andr´e G. Roy
and Bruce L. Rhoads C 2008 JohnWiley & Sons, Ltd
PIC OTE/SPH
PIC OTE/SPH
C 2008 JohnWiley & Sons, Ltd
PIC OTE/SPH
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JWBK179-05 February 26, 2008 17:15 Char Count= 0
74 CH 5 LARGE RIVER CHANNEL CONFLUENCESCH 5 LARGE RIVER CHANNEL CONFLUENCES
1998; Lane et al., 2000; Rhoads and Sukhodolov, 2004). Although investigations of
channel junctions have become increasingly sophisticated, allowing for the identification
of some of the key variables that control confluencemorphodynamics, this advance
has largely focused on small-scale confluences. Until recently, there have been almost
no detailed studies of flow, sediment transport and bed morphology at larger scales,
and it is reasonable to question whether or not current conceptual models of confluence
dynamics are valid for larger rivers (channels ∼>100m wide). This question is
significant as the junctions of smaller channels can be expected to differ considerably
from the junctions of channels several orders of magnitude larger. For example, smaller
channels are usually characterized by relatively low channel widthdepth ratios, whilst
larger channels are usually wider and shallower. Moreover, the junction of two larger
channels may drain significantly different areas in terms of geology and climate, and
can thus have a greater range of inflow conditions at the confluence as compared to
smaller junctions, which more frequently drain areas with similar catchment characteristics.
Understanding the influence of such scale effects on the process dynamics
of large river confluences is vital since they adopt a pivotal role in controlling, and
regulating, the passage of colossal volumes of water and sediment, and determine the
delivery and timing of fluid and sediment discharge to downstream coastal zones and
oceans. Such influences can thus have a wide range of impacts at both the regional and
global scale.
Recent developments in technology, and in particular advances in global positioning
systems and the advent of acoustic Doppler current profiling and multibeam echo
sounding, have begun to facilitate investigations of large river morphodynamics (e.g.
Richardson and Thorne, 2001; McLelland et al., 1999; Ashworth et al., 2000; Parsons
significant as the junctions of smaller channels can be expected to differ considerably
from the junctions of channels several orders of magnitude larger. For example, smaller
channels are usually characterized by relatively low channel widthdepth ratios, whilst
larger channels are usually wider and shallower. Moreover, the junction of two larger
channels may drain significantly different areas in terms of geology and climate, and
can thus have a greater range of inflow conditions at the confluence as compared to
smaller junctions, which more frequently drain areas with similar catchment characteristics.
Understanding the influence of such scale effects on the process dynamics
of large river confluences is vital since they adopt a pivotal role in controlling, and
regulating, the passage of colossal volumes of water and sediment, and determine the
delivery and timing of fluid and sediment discharge to downstream coastal zones and
oceans. Such influences can thus have a wide range of impacts at both the regional and
global scale.
Recent developments in technology, and in particular advances in global positioning
systems and the advent of acoustic Doppler current profiling and multibeam echo
sounding, have begun to facilitate investigations of large river morphodynamics (e.g.
Richardson and Thorne, 2001; McLelland et al., 1999; Ashworth et al., 2000; Parsons
channel junctions have become increasingly sophisticated, allowing for the identification
of some of the key variables that control confluencemorphodynamics, this advance
has largely focused on small-scale confluences. Until recently, there have been almost
no detailed studies of flow, sediment transport and bed morphology at larger scales,
and it is reasonable to question whether or not current conceptual models of confluence
dynamics are valid for larger rivers (channels ∼>100m wide). This question is
significant as the junctions of smaller channels can be expected to differ considerably
from the junctions of channels several orders of magnitude larger. For example, smaller
channels are usually characterized by relatively low channel widthdepth ratios, whilst
larger channels are usually wider and shallower. Moreover, the junction of two larger
channels may drain significantly different areas in terms of geology and climate, and
can thus have a greater range of inflow conditions at the confluence as compared to
smaller junctions, which more frequently drain areas with similar catchment characteristics.
Understanding the influence of such scale effects on the process dynamics
of large river confluences is vital since they adopt a pivotal role in controlling, and
regulating, the passage of colossal volumes of water and sediment, and determine the
delivery and timing of fluid and sediment discharge to downstream coastal zones and
oceans. Such influences can thus have a wide range of impacts at both the regional and
global scale.
Recent developments in technology, and in particular advances in global positioning
systems and the advent of acoustic Doppler current profiling and multibeam echo
sounding, have begun to facilitate investigations of large river morphodynamics (e.g.
Richardson and Thorne, 2001; McLelland et al., 1999; Ashworth et al., 2000; Parsons
significant as the junctions of smaller channels can be expected to differ considerably
from the junctions of channels several orders of magnitude larger. For example, smaller
channels are usually characterized by relatively low channel widthdepth ratios, whilst
larger channels are usually wider and shallower. Moreover, the junction of two larger
channels may drain significantly different areas in terms of geology and climate, and
can thus have a greater range of inflow conditions at the confluence as compared to
smaller junctions, which more frequently drain areas with similar catchment characteristics.
Understanding the influence of such scale effects on the process dynamics
of large river confluences is vital since they adopt a pivotal role in controlling, and
regulating, the passage of colossal volumes of water and sediment, and determine the
delivery and timing of fluid and sediment discharge to downstream coastal zones and
oceans. Such influences can thus have a wide range of impacts at both the regional and
global scale.
Recent developments in technology, and in particular advances in global positioning
systems and the advent of acoustic Doppler current profiling and multibeam echo
sounding, have begun to facilitate investigations of large river morphodynamics (e.g.
Richardson and Thorne, 2001; McLelland et al., 1999; Ashworth et al., 2000; Parsons
et al., 2000; Rhoads and Sukhodolov, 2004). Although investigations of
channel junctions have become increasingly sophisticated, allowing for the identification
of some of the key variables that control confluencemorphodynamics, this advance
has largely focused on small-scale confluences. Until recently, there have been almost
no detailed studies of flow, sediment transport and bed morphology at larger scales,
and it is reasonable to question whether or not current conceptual models of confluence
dynamics are valid for larger rivers (channels ∼>100m wide). This question is
significant as the junctions of smaller channels can be expected to differ considerably
from the junctions of channels several orders of magnitude larger. For example, smaller
channels are usually characterized by relatively low channel widthdepth ratios, whilst
larger channels are usually wider and shallower. Moreover, the junction of two larger
channels may drain significantly different areas in terms of geology and climate, and
can thus have a greater range of inflow conditions at the confluence as compared to
smaller junctions, which more frequently drain areas with similar catchment characteristics.
Understanding the influence of such scale effects on the process dynamics
of large river confluences is vital since they adopt a pivotal role in controlling, and
regulating, the passage of colossal volumes of water and sediment, and determine the
delivery and timing of fluid and sediment discharge to downstream coastal zones and
oceans. Such influences can thus have a wide range of impacts at both the regional and
global scale.
Recent developments in technology, and in particular advances in global positioning
systems and the advent of acoustic Doppler current profiling and multibeam echo
sounding, have begun to facilitate investigations of large river morphodynamics (e.g.
Richardson and Thorne, 2001; McLelland et al., 1999; Ashworth et al., 2000; Parsons
significant as the junctions of smaller channels can be expected to differ considerably
from the junctions of channels several orders of magnitude larger. For example, smaller
channels are usually characterized by relatively low channel widthdepth ratios, whilst
larger channels are usually wider and shallower. Moreover, the junction of two larger
channels may drain significantly different areas in terms of geology and climate, and
can thus have a greater range of inflow conditions at the confluence as compared to
smaller junctions, which more frequently drain areas with similar catchment characteristics.
Understanding the influence of such scale effects on the process dynamics
of large river confluences is vital since they adopt a pivotal role in controlling, and
regulating, the passage of colossal volumes of water and sediment, and determine the
delivery and timing of fluid and sediment discharge to downstream coastal zones and
oceans. Such influences can thus have a wide range of impacts at both the regional and
global scale.
Recent developments in technology, and in particular advances in global positioning
systems and the advent of acoustic Doppler current profiling and multibeam echo
sounding, have begun to facilitate investigations of large river morphodynamics (e.g.
Richardson and Thorne, 2001; McLelland et al., 1999; Ashworth et al., 2000; Parsons
∼>100m wide). This question is
significant as the junctions of smaller channels can be expected to differ considerably
from the junctions of channels several orders of magnitude larger. For example, smaller
channels are usually characterized by relatively low channel widthdepth ratios, whilst
larger channels are usually wider and shallower. Moreover, the junction of two larger
channels may drain significantly different areas in terms of geology and climate, and
can thus have a greater range of inflow conditions at the confluence as compared to
smaller junctions, which more frequently drain areas with similar catchment characteristics.
Understanding the influence of such scale effects on the process dynamics
of large river confluences is vital since they adopt a pivotal role in controlling, and
regulating, the passage of colossal volumes of water and sediment, and determine the
delivery and timing of fluid and sediment discharge to downstream coastal zones and
oceans. Such influences can thus have a wide range of impacts at both the regional and
global scale.
Recent developments in technology, and in particular advances in global positioning
systems and the advent of acoustic Doppler current profiling and multibeam echo
sounding, have begun to facilitate investigations of large river morphodynamics (e.g.
Richardson and Thorne, 2001; McLelland et al., 1999; Ashworth et al., 2000; Parsonset al., 1999; Ashworth et al., 2000; Parsons
et al., 2004, 2005, 2007; Szupiany et al., 2005; Lane et al., inpress). Thesenewinstruments
enable the rapid and precise mapping of flow fields and bed morphology from such
large channels, and the initial results from these investigations (e.g. McLelland et al.,
1999; Parsons et al., 2007) question whether large-scale secondary flows are present at
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
1999; Parsons et al., 2007) question whether large-scale secondary flows are present at
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
enable the rapid and precise mapping of flow fields and bed morphology from such
large channels, and the initial results from these investigations (e.g. McLelland et al.,
1999; Parsons et al., 2007) question whether large-scale secondary flows are present at
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
1999; Parsons et al., 2007) question whether large-scale secondary flows are present at
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
, 2004, 2005, 2007; Szupiany et al., 2005; Lane et al., inpress). Thesenewinstruments
enable the rapid and precise mapping of flow fields and bed morphology from such
large channels, and the initial results from these investigations (e.g. McLelland et al.,
1999; Parsons et al., 2007) question whether large-scale secondary flows are present at
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
1999; Parsons et al., 2007) question whether large-scale secondary flows are present at
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
et al.,
1999; Parsons et al., 2007) question whether large-scale secondary flows are present at
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.
et al., 2007) question whether large-scale secondary flows are present at
large river channel confluences and suggest that boundary-layer effects at higherwidth
depth ratios and the impacts of high form roughness might suppress the development
of such flow structures.
This chapter will examine the influence of scale on junction morphodynamics and
highlight the similarities and differences between large and small confluences. The flow
structure present at larger river confluences will be compared with models developed
for smaller junctions, allowing discussion and speculation on the influence of these
processes on the dynamics of fluid mixing at large river channel confluences. This
chapter presents details from relatively new material, as data on large-scale confluences
are only now becoming available, and highlights some of the challenges that such new
information is raising.