Maritime USRG - University of Southampton

Maritime USRG - University of Southampton

Environment
Simulating the Bed Topography of
Submarine Meanders
Description of the
Submarine meanders scoured by turbidity
research
currents are common features of the deep ocean
floor. Hydrographic surveys have revealed
aspects of their planform morphology, but their
deep water location inhibits access, so
knowledge of their fluid mechanics, sediment
transport and bed morphology remains limited,
conceptual models having been developed
by analogy with the well understood
mechanics of fluvial meanders, due to
similarities between their planform shapes.

This research explores the implications of
this behaviour with respect to the bed
morphology of submarine channel bends.

Research results
Our model replicates the relatively flat
transverse bed profiles observed in the study
bend very well, at least in those parts of the bend
at, and downstream of, the apex (i.e., in the region
of fully developed flow)
Figures
below
indicates
that
submarine
meanders exhibit key differences in bed
morphology relative to equivalent fluvial bends:
In submarine bends the outer-bank pool is
shallower and the point-bar is less
pronounced, giving a transverse bed profile
that is much flatter

However, recent experimental investigations
[Corney et al., 2006; Keevil et al., 2006] have
In submarine bends the point-bar is located
revealed that the secondary flow structure in
further downstream of the bend apex
submarine channels with density-driven
Subaqueous Depth (m)
Subaerial Depth (m)
gravity currents is the opposite to that of
fluvial bends (Figure 1). Unlike sub-aerial
channels, in which the downstream velocity
maximum occurs near the surface, gravity
currents exhibit a near-bed maximum. This
distinction results in the occurrence of outwards
near-bed secondary flow, whereas near-bed
secondary flow is directed inwards in the case
of
Difference in Depth (m)
These data reveal a spectacular
meandering channel system
fluvial bends.
0

High : 156.0

High : 435.0

Low : 73.0

Low : 4.0

4,400

8,800

17,600 Meters

0

4,400

8,800

17,600 Meters

-325.0 to -225.0
-225.0 to -155.0

(location: ~55.5N,137.5W) at a
depth of ~3000 m, and with
dimensions (wavelength = 39.8
km; sinuosity = 1.9; width = 4.75
km, depth = 115 m) consistent
with other submarine channels

-155.0 to -95.0
-95.0 to -40.0
-40.0 to 0.0
0.0 to 55.0
55.0 to 130.0

0

4,400

8,800

Bathymetric survey data for the Gulf of Alaska
region showing the meander system and specific
bend modelled in this study. Data from:
http://www.ccom- jhc.unh.edu/

for more information please contact:
School of Geography, University of Southampton, [email protected]
Web: www.geog.soton.ac.uk
School of Earth and Environment, University of Leeds [email protected] Web:
www.see.leeds.ac.uk

17,600 Meters

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